Add a testcase for probe event argument syntax which ensures the kprobe_events interface correctly parses given event arguments.

Signed-off-by: Masami Hiramatsu mhiramat@kernel.org --- .../ftrace/test.d/kprobe/kprobe_args_syntax.tc | 97 ++++++++++++++++++++ 1 file changed, 97 insertions(+) create mode 100644 tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_syntax.tc

diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_syntax.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_syntax.tc new file mode 100644 index 000000000000..231bcd2c4eb5 --- /dev/null +++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_syntax.tc @@ -0,0 +1,97 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 +# description: Kprobe event argument syntax + +[ -f kprobe_events ] || exit_unsupported # this is configurable + +grep "x8/16/32/64" README > /dev/null || exit_unsupported # version issue + +echo 0 > events/enable +echo > kprobe_events + +PROBEFUNC="vfs_read" +GOODREG= +BADREG= +GOODSYM="_sdata" +if ! grep -qw ${GOODSYM} /proc/kallsyms ; then + GOODSYM=$PROBEFUNC +fi +BADSYM="deaqswdefr" +SYMADDR=0x`grep -w ${GOODSYM} /proc/kallsyms | cut -f 1 -d " "` +GOODTYPE="x16" +BADTYPE="y16" + +case `uname -m` in +x86_64|i[3456]86) + GOODREG=%ax + BADREG=%ex +;; +aarch64) + GOODREG=%x0 + BADREG=%ax +;; +arm*) + GOODREG=%r0 + BADREG=%ax +;; +esac + +test_goodarg() # Good-args +{ + while [ "$1" ]; do + echo "p ${PROBEFUNC} $1" > kprobe_events + shift 1 + done; +} + +test_badarg() # Bad-args +{ + while [ "$1" ]; do + ! echo "p ${PROBEFUNC} $1" > kprobe_events + shift 1 + done; +} + +echo > kprobe_events + +: "Register access" +test_goodarg ${GOODREG} +test_badarg ${BADREG} + +: "Symbol access" +test_goodarg "@${GOODSYM}" "@${SYMADDR}" "@${GOODSYM}+10" "@${GOODSYM}-10" +test_badarg "@" "@${BADSYM}" "@${GOODSYM}*10" "@${GOODSYM}/10" \ + "@${GOODSYM}%10" "@${GOODSYM}&10" "@${GOODSYM}|10" + +: "Stack access" +test_goodarg "$stack" "$stack0" "$stack1" +test_badarg "$stackp" "$stack0+10" "$stack1-10" + +: "Retval access" +echo "r ${PROBEFUNC} $retval" > kprobe_events +! echo "p ${PROBEFUNC} $retval" > kprobe_events + +: "Comm access" +test_goodarg "$comm" + +: "Indirect memory access" +test_goodarg "+0(${GOODREG})" "-0(${GOODREG})" "+10($stack)" \ + "+0($stack1)" "+10(@${GOODSYM}-10)" "+0(+10(+20($stack)))" +test_badarg "+(${GOODREG})" "(${GOODREG}+10)" "-(${GOODREG})" "(${GOODREG})" \ + "+10($comm)" "+0(${GOODREG})+10" + +: "Name assignment" +test_goodarg "varname=${GOODREG}" +test_badarg "varname=varname2=${GOODREG}" + +: "Type syntax" +test_goodarg "${GOODREG}:${GOODTYPE}" +test_badarg "${GOODREG}::${GOODTYPE}" "${GOODREG}:${BADTYPE}" \ + "${GOODTYPE}:${GOODREG}" + +: "Combination check" + +test_goodarg "$comm:string" "+0($stack):string" +test_badarg "$comm:x64" "$stack:string" "${GOODREG}:string" + +echo > kprobe_events

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Add a testcase for probe point definition. This tests symbol, address and symbol+offset syntax. The offset must be positive and smaller than UINT_MAX.

Signed-off-by: Masami Hiramatsu mhiramat@kernel.org --- .../selftests/ftrace/test.d/kprobe/probepoint.tc | 43 ++++++++++++++++++++ 1 file changed, 43 insertions(+) create mode 100644 tools/testing/selftests/ftrace/test.d/kprobe/probepoint.tc

diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/probepoint.tc b/tools/testing/selftests/ftrace/test.d/kprobe/probepoint.tc new file mode 100644 index 000000000000..4fda01a08da4 --- /dev/null +++ b/tools/testing/selftests/ftrace/test.d/kprobe/probepoint.tc @@ -0,0 +1,43 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 +# description: Kprobe events - probe points + +[ -f kprobe_events ] || exit_unsupported # this is configurable + +TARGET_FUNC=create_trace_kprobe + +dec_addr() { # hexaddr + printf "%d" "0x"`echo $1 | tail -c 8` +} + +set_offs() { # prev target next + A1=`dec_addr $1` + A2=`dec_addr $2` + A3=`dec_addr $3` + TARGET="0x$2" # an address + PREV=`expr $A1 - $A2` # offset to previous symbol + NEXT=+`expr $A3 - $A2` # offset to next symbol + OVERFLOW=+`printf "0x%x" ${PREV}` # overflow offset to previous symbol +} + +# We have to decode symbol addresses to get correct offsets. +# If the offset is not an instruction boundary, it cause -EILSEQ. +set_offs `grep -A1 -B1 ${TARGET_FUNC} /proc/kallsyms | cut -f 1 -d " " | xargs` + +UINT_TEST=no +# printf "%x" -1 returns (unsigned long)-1. +if [ `printf "%x" -1 | wc -c` != 9 ]; then + UINT_TEST=yes +fi + +echo 0 > events/enable +echo > kprobe_events +echo "p:testprobe ${TARGET_FUNC}" > kprobe_events +echo "p:testprobe ${TARGET}" > kprobe_events +echo "p:testprobe ${TARGET_FUNC}${NEXT}" > kprobe_events +! echo "p:testprobe ${TARGET_FUNC}${PREV}" > kprobe_events +if [ "${UINT_TEST}" = yes ]; then +! echo "p:testprobe ${TARGET_FUNC}${OVERFLOW}" > kprobe_events +fi +echo > kprobe_events +clear_trace

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Cleanup event argument definition code in one place for maintenancability.

Signed-off-by: Masami Hiramatsu mhiramat@kernel.org --- kernel/trace/trace_kprobe.c | 32 ++++---------------------------- kernel/trace/trace_probe.c | 21 +++++++++++++++++++++ kernel/trace/trace_probe.h | 2 ++ kernel/trace/trace_uprobe.c | 15 ++------------- 4 files changed, 29 insertions(+), 41 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 81e2eb5a1566..a8f8cce066a9 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -1146,49 +1146,25 @@ print_kretprobe_event(struct trace_iterator *iter, int flags,

static int kprobe_event_define_fields(struct trace_event_call *event_call) { - int ret, i; + int ret; struct kprobe_trace_entry_head field; struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;

DEFINE_FIELD(unsigned long, ip, FIELD_STRING_IP, 0); - /* Set argument names as fields */ - for (i = 0; i < tk->tp.nr_args; i++) { - struct probe_arg *parg = &tk->tp.args[i];

- ret = trace_define_field(event_call, parg->type->fmttype, - parg->name, - sizeof(field) + parg->offset, - parg->type->size, - parg->type->is_signed, - FILTER_OTHER); - if (ret) - return ret; - } - return 0; + return traceprobe_define_arg_fields(event_call, sizeof(field), &tk->tp); }

static int kretprobe_event_define_fields(struct trace_event_call *event_call) { - int ret, i; + int ret; struct kretprobe_trace_entry_head field; struct trace_kprobe *tk = (struct trace_kprobe *)event_call->data;

DEFINE_FIELD(unsigned long, func, FIELD_STRING_FUNC, 0); DEFINE_FIELD(unsigned long, ret_ip, FIELD_STRING_RETIP, 0); - /* Set argument names as fields */ - for (i = 0; i < tk->tp.nr_args; i++) { - struct probe_arg *parg = &tk->tp.args[i];

- ret = trace_define_field(event_call, parg->type->fmttype, - parg->name, - sizeof(field) + parg->offset, - parg->type->size, - parg->type->is_signed, - FILTER_OTHER); - if (ret) - return ret; - } - return 0; + return traceprobe_define_arg_fields(event_call, sizeof(field), &tk->tp); }

#ifdef CONFIG_PERF_EVENTS diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c index 8894b81e29b0..049e8531fdf8 100644 --- a/kernel/trace/trace_probe.c +++ b/kernel/trace/trace_probe.c @@ -680,3 +680,24 @@ int set_print_fmt(struct trace_probe *tp, bool is_return)

return 0; } + +int traceprobe_define_arg_fields(struct trace_event_call *event_call, + size_t offset, struct trace_probe *tp) +{ + int ret, i; + + /* Set argument names as fields */ + for (i = 0; i < tp->nr_args; i++) { + struct probe_arg *parg = &tp->args[i]; + + ret = trace_define_field(event_call, parg->type->fmttype, + parg->name, + offset + parg->offset, + parg->type->size, + parg->type->is_signed, + FILTER_OTHER); + if (ret) + return ret; + } + return 0; +} diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h index 0c8e66f9c855..de928052926b 100644 --- a/kernel/trace/trace_probe.h +++ b/kernel/trace/trace_probe.h @@ -440,3 +440,5 @@ extern struct trace_event_call * create_local_trace_uprobe(char *name, unsigned long offs, bool is_return); extern void destroy_local_trace_uprobe(struct trace_event_call *event_call); #endif +extern int traceprobe_define_arg_fields(struct trace_event_call *event_call, + size_t offset, struct trace_probe *tp); diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c index 4c006a693663..887da2bb63aa 100644 --- a/kernel/trace/trace_uprobe.c +++ b/kernel/trace/trace_uprobe.c @@ -982,7 +982,7 @@ probe_event_disable(struct trace_uprobe *tu, struct trace_event_file *file)

static int uprobe_event_define_fields(struct trace_event_call *event_call) { - int ret, i, size; + int ret, size; struct uprobe_trace_entry_head field; struct trace_uprobe *tu = event_call->data;

@@ -994,19 +994,8 @@ static int uprobe_event_define_fields(struct trace_event_call *event_call) DEFINE_FIELD(unsigned long, vaddr[0], FIELD_STRING_IP, 0); size = SIZEOF_TRACE_ENTRY(false); } - /* Set argument names as fields */ - for (i = 0; i < tu->tp.nr_args; i++) { - struct probe_arg *parg = &tu->tp.args[i]; - - ret = trace_define_field(event_call, parg->type->fmttype, - parg->name, size + parg->offset, - parg->type->size, parg->type->is_signed, - FILTER_OTHER);

- if (ret) - return ret; - } - return 0; + return traceprobe_define_arg_fields(event_call, size, &tu->tp); }

#ifdef CONFIG_PERF_EVENTS

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Replace {k,u}probe event argument fetching framework with switch-case based. Currently that is implemented with structures, macros and chain of function-pointers, which is more complicated than necessary and may get a performance penalty by retpoline.

This simplify that with an array of "fetch_insn" (opcode and oprands), and make process_fetch_insn() just interprets it. No function pointers are used.

Signed-off-by: Masami Hiramatsu mhiramat@kernel.org --- Changes in v3: - Split out probe type table unification. --- kernel/trace/trace_kprobe.c | 291 +++++++++++++--------------- kernel/trace/trace_probe.c | 401 +++++++++++---------------------------- kernel/trace/trace_probe.h | 230 ++++------------------ kernel/trace/trace_probe_tmpl.h | 120 ++++++++++++ kernel/trace/trace_uprobe.c | 127 ++++++++---- 5 files changed, 491 insertions(+), 678 deletions(-) create mode 100644 kernel/trace/trace_probe_tmpl.h

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index a8f8cce066a9..1d1e37058f8a 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -24,6 +24,7 @@ #include <linux/error-injection.h>

#include "trace_probe.h" +#include "trace_probe_tmpl.h"

#define KPROBE_EVENT_SYSTEM "kprobes" #define KRETPROBE_MAXACTIVE_MAX 4096 @@ -121,160 +122,6 @@ static int kprobe_dispatcher(struct kprobe *kp, struct pt_regs *regs); static int kretprobe_dispatcher(struct kretprobe_instance *ri, struct pt_regs *regs);

-/* Memory fetching by symbol */ -struct symbol_cache { - char *symbol; - long offset; - unsigned long addr; -}; - -unsigned long update_symbol_cache(struct symbol_cache *sc) -{ - sc->addr = (unsigned long)kallsyms_lookup_name(sc->symbol); - - if (sc->addr) - sc->addr += sc->offset; - - return sc->addr; -} - -void free_symbol_cache(struct symbol_cache *sc) -{ - kfree(sc->symbol); - kfree(sc); -} - -struct symbol_cache *alloc_symbol_cache(const char *sym, long offset) -{ - struct symbol_cache *sc; - - if (!sym || strlen(sym) == 0) - return NULL; - - sc = kzalloc(sizeof(struct symbol_cache), GFP_KERNEL); - if (!sc) - return NULL; - - sc->symbol = kstrdup(sym, GFP_KERNEL); - if (!sc->symbol) { - kfree(sc); - return NULL; - } - sc->offset = offset; - update_symbol_cache(sc); - - return sc; -} - -/* - * Kprobes-specific fetch functions - */ -#define DEFINE_FETCH_stack(type) \ -static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs, \ - void *offset, void *dest) \ -{ \ - *(type *)dest = (type)regs_get_kernel_stack_nth(regs, \ - (unsigned int)((unsigned long)offset)); \ -} \ -NOKPROBE_SYMBOL(FETCH_FUNC_NAME(stack, type)); - -DEFINE_BASIC_FETCH_FUNCS(stack) -/* No string on the stack entry */ -#define fetch_stack_string NULL -#define fetch_stack_string_size NULL - -#define DEFINE_FETCH_memory(type) \ -static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs, \ - void *addr, void *dest) \ -{ \ - type retval; \ - if (probe_kernel_address(addr, retval)) \ - *(type *)dest = 0; \ - else \ - *(type *)dest = retval; \ -} \ -NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, type)); - -DEFINE_BASIC_FETCH_FUNCS(memory) -/* - * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max - * length and relative data location. - */ -static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs, - void *addr, void *dest) -{ - int maxlen = get_rloc_len(*(u32 *)dest); - u8 *dst = get_rloc_data(dest); - long ret; - - if (!maxlen) - return; - - /* - * Try to get string again, since the string can be changed while - * probing. - */ - ret = strncpy_from_unsafe(dst, addr, maxlen); - - if (ret < 0) { /* Failed to fetch string */ - dst[0] = '\0'; - *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest)); - } else { - *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest)); - } -} -NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string)); - -/* Return the length of string -- including null terminal byte */ -static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs, - void *addr, void *dest) -{ - mm_segment_t old_fs; - int ret, len = 0; - u8 c; - - old_fs = get_fs(); - set_fs(KERNEL_DS); - pagefault_disable(); - - do { - ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1); - len++; - } while (c && ret == 0 && len < MAX_STRING_SIZE); - - pagefault_enable(); - set_fs(old_fs); - - if (ret < 0) /* Failed to check the length */ - *(u32 *)dest = 0; - else - *(u32 *)dest = len; -} -NOKPROBE_SYMBOL(FETCH_FUNC_NAME(memory, string_size)); - -#define DEFINE_FETCH_symbol(type) \ -void FETCH_FUNC_NAME(symbol, type)(struct pt_regs *regs, void *data, void *dest)\ -{ \ - struct symbol_cache *sc = data; \ - if (sc->addr) \ - fetch_memory_##type(regs, (void *)sc->addr, dest); \ - else \ - *(type *)dest = 0; \ -} \ -NOKPROBE_SYMBOL(FETCH_FUNC_NAME(symbol, type)); - -DEFINE_BASIC_FETCH_FUNCS(symbol) -DEFINE_FETCH_symbol(string) -DEFINE_FETCH_symbol(string_size) - -/* kprobes don't support file_offset fetch methods */ -#define fetch_file_offset_u8 NULL -#define fetch_file_offset_u16 NULL -#define fetch_file_offset_u32 NULL -#define fetch_file_offset_u64 NULL -#define fetch_file_offset_string NULL -#define fetch_file_offset_string_size NULL - /* Fetch type information table */ static const struct fetch_type kprobes_fetch_type_table[] = { /* Special types */ @@ -490,14 +337,11 @@ disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file) /* Internal register function - just handle k*probes and flags */ static int __register_trace_kprobe(struct trace_kprobe *tk) { - int i, ret; + int ret;

if (trace_probe_is_registered(&tk->tp)) return -EINVAL;

- for (i = 0; i < tk->tp.nr_args; i++) - traceprobe_update_arg(&tk->tp.args[i]); - /* Set/clear disabled flag according to tp->flag */ if (trace_probe_is_enabled(&tk->tp)) tk->rp.kp.flags &= ~KPROBE_FLAG_DISABLED; @@ -830,8 +674,8 @@ static int create_trace_kprobe(int argc, char **argv)

/* Parse fetch argument */ ret = traceprobe_parse_probe_arg(arg, &tk->tp.size, parg, - is_return, true, - kprobes_fetch_type_table); + is_return, true, + kprobes_fetch_type_table); if (ret) { pr_info("Parse error at argument[%d]. (%d)\n", i, ret); goto error; @@ -985,6 +829,133 @@ static const struct file_operations kprobe_profile_ops = { .release = seq_release, };

+/* Kprobe specific fetch functions */ + +/* Return the length of string -- including null terminal byte */ +static nokprobe_inline void +fetch_store_strlen(unsigned long addr, void *dest) +{ + mm_segment_t old_fs; + int ret, len = 0; + u8 c; + + old_fs = get_fs(); + set_fs(KERNEL_DS); + pagefault_disable(); + + do { + ret = __copy_from_user_inatomic(&c, (u8 *)addr + len, 1); + len++; + } while (c && ret == 0 && len < MAX_STRING_SIZE); + + pagefault_enable(); + set_fs(old_fs); + + if (ret < 0) /* Failed to check the length */ + *(u32 *)dest = 0; + else + *(u32 *)dest = len; +} + +/* + * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max + * length and relative data location. + */ +static nokprobe_inline void +fetch_store_string(unsigned long addr, void *dest) +{ + int maxlen = get_rloc_len(*(u32 *)dest); + u8 *dst = get_rloc_data(dest); + long ret; + + if (!maxlen) + return; + + /* + * Try to get string again, since the string can be changed while + * probing. + */ + ret = strncpy_from_unsafe(dst, (void *)addr, maxlen); + + if (ret < 0) { /* Failed to fetch string */ + dst[0] = '\0'; + *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest)); + } else { + *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest)); + } +} + +/* Note that we don't verify it, since the code does not come from user space */ +static int +process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, + bool pre) +{ + unsigned long val; + int ret; + + /* 1st stage: get value from context */ + switch (code->op) { + case FETCH_OP_REG: + val = regs_get_register(regs, code->param); + break; + case FETCH_OP_STACK: + val = regs_get_kernel_stack_nth(regs, code->param); + break; + case FETCH_OP_STACKP: + val = kernel_stack_pointer(regs); + break; + case FETCH_OP_RETVAL: + val = regs_return_value(regs); + break; + case FETCH_OP_IMM: + val = code->immediate; + break; + case FETCH_OP_COMM: + val = (unsigned long)current->comm; + break; + default: + return -EILSEQ; + } + code++; + + /* 2nd stage: dereference memory if needed */ + while (code->op == FETCH_OP_DEREF) { + ret = probe_kernel_read(&val, (void *)val + code->offset, + sizeof(val)); + if (ret) + return ret; + code++; + } + + /* 3rd stage: store value to buffer */ + switch (code->op) { + case FETCH_OP_ST_RAW: + fetch_store_raw(val, code, dest); + break; + case FETCH_OP_ST_MEM: + probe_kernel_read(dest, (void *)val + code->offset, code->size); + break; + case FETCH_OP_ST_STRING: + if (pre) + fetch_store_strlen(val + code->offset, dest); + else + fetch_store_string(val + code->offset, dest); + break; + default: + return -EILSEQ; + } + code++; + + /* 4th stage: modify stored value if needed */ + if (code->op == FETCH_OP_MOD_BF) { + fetch_apply_bitfield(code, dest); + code++; + } + + return code->op == FETCH_OP_END ? 0 : -EILSEQ; +} +NOKPROBE_SYMBOL(process_fetch_insn) + /* Kprobe handler */ static nokprobe_inline void __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs, diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c index 51ca8f751332..758968ac165d 100644 --- a/kernel/trace/trace_probe.c +++ b/kernel/trace/trace_probe.c @@ -73,174 +73,6 @@ int PRINT_TYPE_FUNC_NAME(string)(struct trace_seq *s, void *data, void *ent)

const char PRINT_TYPE_FMT_NAME(string)[] = "\"%s\"";

-#define CHECK_FETCH_FUNCS(method, fn) \ - (((FETCH_FUNC_NAME(method, u8) == fn) || \ - (FETCH_FUNC_NAME(method, u16) == fn) || \ - (FETCH_FUNC_NAME(method, u32) == fn) || \ - (FETCH_FUNC_NAME(method, u64) == fn) || \ - (FETCH_FUNC_NAME(method, string) == fn) || \ - (FETCH_FUNC_NAME(method, string_size) == fn)) \ - && (fn != NULL)) - -/* Data fetch function templates */ -#define DEFINE_FETCH_reg(type) \ -void FETCH_FUNC_NAME(reg, type)(struct pt_regs *regs, void *offset, void *dest) \ -{ \ - *(type *)dest = (type)regs_get_register(regs, \ - (unsigned int)((unsigned long)offset)); \ -} \ -NOKPROBE_SYMBOL(FETCH_FUNC_NAME(reg, type)); -DEFINE_BASIC_FETCH_FUNCS(reg) -/* No string on the register */ -#define fetch_reg_string NULL -#define fetch_reg_string_size NULL - -#define DEFINE_FETCH_retval(type) \ -void FETCH_FUNC_NAME(retval, type)(struct pt_regs *regs, \ - void *dummy, void *dest) \ -{ \ - *(type *)dest = (type)regs_return_value(regs); \ -} \ -NOKPROBE_SYMBOL(FETCH_FUNC_NAME(retval, type)); -DEFINE_BASIC_FETCH_FUNCS(retval) -/* No string on the retval */ -#define fetch_retval_string NULL -#define fetch_retval_string_size NULL - -/* Dereference memory access function */ -struct deref_fetch_param { - struct fetch_param orig; - long offset; - fetch_func_t fetch; - fetch_func_t fetch_size; -}; - -#define DEFINE_FETCH_deref(type) \ -void FETCH_FUNC_NAME(deref, type)(struct pt_regs *regs, \ - void *data, void *dest) \ -{ \ - struct deref_fetch_param *dprm = data; \ - unsigned long addr; \ - call_fetch(&dprm->orig, regs, &addr); \ - if (addr) { \ - addr += dprm->offset; \ - dprm->fetch(regs, (void *)addr, dest); \ - } else \ - *(type *)dest = 0; \ -} \ -NOKPROBE_SYMBOL(FETCH_FUNC_NAME(deref, type)); -DEFINE_BASIC_FETCH_FUNCS(deref) -DEFINE_FETCH_deref(string) - -void FETCH_FUNC_NAME(deref, string_size)(struct pt_regs *regs, - void *data, void *dest) -{ - struct deref_fetch_param *dprm = data; - unsigned long addr; - - call_fetch(&dprm->orig, regs, &addr); - if (addr && dprm->fetch_size) { - addr += dprm->offset; - dprm->fetch_size(regs, (void *)addr, dest); - } else - *(string_size *)dest = 0; -} -NOKPROBE_SYMBOL(FETCH_FUNC_NAME(deref, string_size)); - -static void update_deref_fetch_param(struct deref_fetch_param *data) -{ - if (CHECK_FETCH_FUNCS(deref, data->orig.fn)) - update_deref_fetch_param(data->orig.data); - else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn)) - update_symbol_cache(data->orig.data); -} -NOKPROBE_SYMBOL(update_deref_fetch_param); - -static void free_deref_fetch_param(struct deref_fetch_param *data) -{ - if (CHECK_FETCH_FUNCS(deref, data->orig.fn)) - free_deref_fetch_param(data->orig.data); - else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn)) - free_symbol_cache(data->orig.data); - kfree(data); -} -NOKPROBE_SYMBOL(free_deref_fetch_param); - -/* Bitfield fetch function */ -struct bitfield_fetch_param { - struct fetch_param orig; - unsigned char hi_shift; - unsigned char low_shift; -}; - -#define DEFINE_FETCH_bitfield(type) \ -void FETCH_FUNC_NAME(bitfield, type)(struct pt_regs *regs, \ - void *data, void *dest) \ -{ \ - struct bitfield_fetch_param *bprm = data; \ - type buf = 0; \ - call_fetch(&bprm->orig, regs, &buf); \ - if (buf) { \ - buf <<= bprm->hi_shift; \ - buf >>= bprm->low_shift; \ - } \ - *(type *)dest = buf; \ -} \ -NOKPROBE_SYMBOL(FETCH_FUNC_NAME(bitfield, type)); -DEFINE_BASIC_FETCH_FUNCS(bitfield) -#define fetch_bitfield_string NULL -#define fetch_bitfield_string_size NULL - -static void -update_bitfield_fetch_param(struct bitfield_fetch_param *data) -{ - /* - * Don't check the bitfield itself, because this must be the - * last fetch function. - */ - if (CHECK_FETCH_FUNCS(deref, data->orig.fn)) - update_deref_fetch_param(data->orig.data); - else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn)) - update_symbol_cache(data->orig.data); -} - -static void -free_bitfield_fetch_param(struct bitfield_fetch_param *data) -{ - /* - * Don't check the bitfield itself, because this must be the - * last fetch function. - */ - if (CHECK_FETCH_FUNCS(deref, data->orig.fn)) - free_deref_fetch_param(data->orig.data); - else if (CHECK_FETCH_FUNCS(symbol, data->orig.fn)) - free_symbol_cache(data->orig.data); - - kfree(data); -} - -void FETCH_FUNC_NAME(comm, string)(struct pt_regs *regs, - void *data, void *dest) -{ - int maxlen = get_rloc_len(*(u32 *)dest); - u8 *dst = get_rloc_data(dest); - long ret; - - if (!maxlen) - return; - - ret = strlcpy(dst, current->comm, maxlen); - *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest)); -} -NOKPROBE_SYMBOL(FETCH_FUNC_NAME(comm, string)); - -void FETCH_FUNC_NAME(comm, string_size)(struct pt_regs *regs, - void *data, void *dest) -{ - *(u32 *)dest = strlen(current->comm) + 1; -} -NOKPROBE_SYMBOL(FETCH_FUNC_NAME(comm, string_size)); - static const struct fetch_type *find_fetch_type(const char *type, const struct fetch_type *ftbl) { @@ -284,37 +116,6 @@ static const struct fetch_type *find_fetch_type(const char *type, return NULL; }

-/* Special function : only accept unsigned long */ -static void fetch_kernel_stack_address(struct pt_regs *regs, void *dummy, void *dest) -{ - *(unsigned long *)dest = kernel_stack_pointer(regs); -} -NOKPROBE_SYMBOL(fetch_kernel_stack_address); - -static void fetch_user_stack_address(struct pt_regs *regs, void *dummy, void *dest) -{ - *(unsigned long *)dest = user_stack_pointer(regs); -} -NOKPROBE_SYMBOL(fetch_user_stack_address); - -static fetch_func_t get_fetch_size_function(const struct fetch_type *type, - fetch_func_t orig_fn, - const struct fetch_type *ftbl) -{ - int i; - - if (type != &ftbl[FETCH_TYPE_STRING]) - return NULL; /* Only string type needs size function */ - - for (i = 0; i < FETCH_MTD_END; i++) - if (type->fetch[i] == orig_fn) - return ftbl[FETCH_TYPE_STRSIZE].fetch[i]; - - WARN_ON(1); /* This should not happen */ - - return NULL; -} - /* Split symbol and offset. */ int traceprobe_split_symbol_offset(char *symbol, long *offset) { @@ -339,7 +140,7 @@ int traceprobe_split_symbol_offset(char *symbol, long *offset) #define PARAM_MAX_STACK (THREAD_SIZE / sizeof(unsigned long))

static int parse_probe_vars(char *arg, const struct fetch_type *t, - struct fetch_param *f, bool is_return, + struct fetch_insn *code, bool is_return, bool is_kprobe) { int ret = 0; @@ -347,33 +148,24 @@ static int parse_probe_vars(char *arg, const struct fetch_type *t,

if (strcmp(arg, "retval") == 0) { if (is_return) - f->fn = t->fetch[FETCH_MTD_retval]; + code->op = FETCH_OP_RETVAL; else ret = -EINVAL; } else if (strncmp(arg, "stack", 5) == 0) { if (arg[5] == '\0') { - if (strcmp(t->name, DEFAULT_FETCH_TYPE_STR)) - return -EINVAL; - - if (is_kprobe) - f->fn = fetch_kernel_stack_address; - else - f->fn = fetch_user_stack_address; + code->op = FETCH_OP_STACKP; } else if (isdigit(arg[5])) { ret = kstrtoul(arg + 5, 10, &param); if (ret || (is_kprobe && param > PARAM_MAX_STACK)) ret = -EINVAL; else { - f->fn = t->fetch[FETCH_MTD_stack]; - f->data = (void *)param; + code->op = FETCH_OP_STACK; + code->param = (unsigned int)param; } } else ret = -EINVAL; } else if (strcmp(arg, "comm") == 0) { - if (strcmp(t->name, "string") != 0 && - strcmp(t->name, "string_size") != 0) - return -EINVAL; - f->fn = t->fetch[FETCH_MTD_comm]; + code->op = FETCH_OP_COMM; } else ret = -EINVAL;

@@ -381,10 +173,13 @@ static int parse_probe_vars(char *arg, const struct fetch_type *t, }

/* Recursive argument parser */ -static int parse_probe_arg(char *arg, const struct fetch_type *t, - struct fetch_param *f, bool is_return, bool is_kprobe, - const struct fetch_type *ftbl) +static int +parse_probe_arg(char *arg, const struct fetch_type *type, + struct fetch_insn **pcode, struct fetch_insn *end, + bool is_return, bool is_kprobe, + const struct fetch_type *ftbl) { + struct fetch_insn *code = *pcode; unsigned long param; long offset; char *tmp; @@ -392,14 +187,15 @@ static int parse_probe_arg(char *arg, const struct fetch_type *t,

switch (arg[0]) { case '$': - ret = parse_probe_vars(arg + 1, t, f, is_return, is_kprobe); + ret = parse_probe_vars(arg + 1, type, code, + is_return, is_kprobe); break;

case '%': /* named register */ ret = regs_query_register_offset(arg + 1); if (ret >= 0) { - f->fn = t->fetch[FETCH_MTD_reg]; - f->data = (void *)(unsigned long)ret; + code->op = FETCH_OP_REG; + code->param = (unsigned int)ret; ret = 0; } break; @@ -409,9 +205,9 @@ static int parse_probe_arg(char *arg, const struct fetch_type *t, ret = kstrtoul(arg + 1, 0, &param); if (ret) break; - - f->fn = t->fetch[FETCH_MTD_memory]; - f->data = (void *)param; + /* load address */ + code->op = FETCH_OP_IMM; + code->immediate = param; } else if (arg[1] == '+') { /* kprobes don't support file offsets */ if (is_kprobe) @@ -421,8 +217,8 @@ static int parse_probe_arg(char *arg, const struct fetch_type *t, if (ret) break;

- f->fn = t->fetch[FETCH_MTD_file_offset]; - f->data = (void *)offset; + code->op = FETCH_OP_FOFFS; + code->immediate = (unsigned long)offset; // imm64? } else { /* uprobes don't support symbols */ if (!is_kprobe) @@ -432,10 +228,19 @@ static int parse_probe_arg(char *arg, const struct fetch_type *t, if (ret) break;

- f->data = alloc_symbol_cache(arg + 1, offset); - if (f->data) - f->fn = t->fetch[FETCH_MTD_symbol]; + code->op = FETCH_OP_IMM; + code->immediate = + (unsigned long)kallsyms_lookup_name(arg + 1); + if (!code->immediate) + return -ENOENT; + code->immediate += offset; } + /* These are fetching from memory */ + if (++code == end) + return -E2BIG; + *pcode = code; + code->op = FETCH_OP_DEREF; + code->offset = offset; break;

case '+': /* deref memory */ @@ -443,11 +248,10 @@ static int parse_probe_arg(char *arg, const struct fetch_type *t, case '-': tmp = strchr(arg, '('); if (!tmp) - break; + return -EINVAL;

*tmp = '\0'; ret = kstrtol(arg, 0, &offset); - if (ret) break;

@@ -455,36 +259,29 @@ static int parse_probe_arg(char *arg, const struct fetch_type *t, tmp = strrchr(arg, ')');

if (tmp) { - struct deref_fetch_param *dprm; - const struct fetch_type *t2; + const struct fetch_type *t2;

t2 = find_fetch_type(NULL, ftbl); *tmp = '\0'; - dprm = kzalloc(sizeof(struct deref_fetch_param), GFP_KERNEL); - - if (!dprm) - return -ENOMEM; - - dprm->offset = offset; - dprm->fetch = t->fetch[FETCH_MTD_memory]; - dprm->fetch_size = get_fetch_size_function(t, - dprm->fetch, ftbl); - ret = parse_probe_arg(arg, t2, &dprm->orig, is_return, - is_kprobe, ftbl); + ret = parse_probe_arg(arg, t2, &code, end, is_return, + is_kprobe, ftbl); if (ret) - kfree(dprm); - else { - f->fn = t->fetch[FETCH_MTD_deref]; - f->data = (void *)dprm; - } + break; + if (code->op == FETCH_OP_COMM) + return -EINVAL; + if (++code == end) + return -E2BIG; + *pcode = code; + + code->op = FETCH_OP_DEREF; + code->offset = offset; } break; } - if (!ret && !f->fn) { /* Parsed, but do not find fetch method */ - pr_info("%s type has no corresponding fetch method.\n", t->name); + if (!ret && code->op == FETCH_OP_NOP) { + /* Parsed, but do not find fetch method */ ret = -EINVAL; } - return ret; }

@@ -493,22 +290,15 @@ static int parse_probe_arg(char *arg, const struct fetch_type *t, /* Bitfield type needs to be parsed into a fetch function */ static int __parse_bitfield_probe_arg(const char *bf, const struct fetch_type *t, - struct fetch_param *f) + struct fetch_insn **pcode) { - struct bitfield_fetch_param *bprm; + struct fetch_insn *code = *pcode; unsigned long bw, bo; char *tail;

if (*bf != 'b') return 0;

- bprm = kzalloc(sizeof(*bprm), GFP_KERNEL); - if (!bprm) - return -ENOMEM; - - bprm->orig = *f; - f->fn = t->fetch[FETCH_MTD_bitfield]; - f->data = (void *)bprm; bw = simple_strtoul(bf + 1, &tail, 0); /* Use simple one */

if (bw == 0 || *tail != '@') @@ -519,9 +309,15 @@ static int __parse_bitfield_probe_arg(const char *bf,

if (tail == bf || *tail != '/') return -EINVAL; + code++; + if (code->op != FETCH_OP_NOP) + return -E2BIG; + *pcode = code;

- bprm->hi_shift = BYTES_TO_BITS(t->size) - (bw + bo); - bprm->low_shift = bprm->hi_shift + bo; + code->op = FETCH_OP_MOD_BF; + code->lshift = BYTES_TO_BITS(t->size) - (bw + bo); + code->rshift = BYTES_TO_BITS(t->size) - bw; + code->basesize = t->size;

return (BYTES_TO_BITS(t->size) < (bw + bo)) ? -EINVAL : 0; } @@ -531,6 +327,7 @@ int traceprobe_parse_probe_arg(char *arg, ssize_t *size, struct probe_arg *parg, bool is_return, bool is_kprobe, const struct fetch_type *ftbl) { + struct fetch_insn *code, *tmp = NULL; const char *t; int ret;

@@ -561,18 +358,60 @@ int traceprobe_parse_probe_arg(char *arg, ssize_t *size, } parg->offset = *size; *size += parg->type->size; - ret = parse_probe_arg(arg, parg->type, &parg->fetch, is_return, - is_kprobe, ftbl); - - if (ret >= 0 && t != NULL) - ret = __parse_bitfield_probe_arg(t, parg->type, &parg->fetch);

- if (ret >= 0) { - parg->fetch_size.fn = get_fetch_size_function(parg->type, - parg->fetch.fn, - ftbl); - parg->fetch_size.data = parg->fetch.data; + code = tmp = kzalloc(sizeof(*code) * FETCH_INSN_MAX, GFP_KERNEL); + if (!code) + return -ENOMEM; + code[FETCH_INSN_MAX - 1].op = FETCH_OP_END; + + ret = parse_probe_arg(arg, parg->type, &code, &code[FETCH_INSN_MAX - 1], + is_return, is_kprobe, ftbl); + if (ret) + goto fail; + + /* Store operation */ + if (!strcmp(parg->type->name, "string")) { + if (code->op != FETCH_OP_DEREF && code->op != FETCH_OP_IMM && + code->op != FETCH_OP_COMM) { + pr_info("string only accepts memory or address.\n"); + ret = -EINVAL; + goto fail; + } + /* Since IMM or COMM must be the 1st insn, this is safe */ + if (code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM) + code++; + code->op = FETCH_OP_ST_STRING; /* In DEREF case, replace it */ + parg->dynamic = true; + } else if (code->op == FETCH_OP_DEREF) { + code->op = FETCH_OP_ST_MEM; + code->size = parg->type->size; + } else { + code++; + if (code->op != FETCH_OP_NOP) { + ret = -E2BIG; + goto fail; + } + code->op = FETCH_OP_ST_RAW; + code->size = parg->type->size; + } + /* Modify operation */ + if (t != NULL) { + ret = __parse_bitfield_probe_arg(t, parg->type, &code); + if (ret) + goto fail; } + code++; + code->op = FETCH_OP_END; + + /* Shrink down the code buffer */ + parg->code = kzalloc(sizeof(*code) * (code - tmp + 1), GFP_KERNEL); + if (!parg->code) + ret = -ENOMEM; + else + memcpy(parg->code, tmp, sizeof(*code) * (code - tmp + 1)); + +fail: + kfree(tmp);

return ret; } @@ -594,25 +433,9 @@ int traceprobe_conflict_field_name(const char *name, return 0; }

-void traceprobe_update_arg(struct probe_arg *arg) -{ - if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn)) - update_bitfield_fetch_param(arg->fetch.data); - else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn)) - update_deref_fetch_param(arg->fetch.data); - else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn)) - update_symbol_cache(arg->fetch.data); -} - void traceprobe_free_probe_arg(struct probe_arg *arg) { - if (CHECK_FETCH_FUNCS(bitfield, arg->fetch.fn)) - free_bitfield_fetch_param(arg->fetch.data); - else if (CHECK_FETCH_FUNCS(deref, arg->fetch.fn)) - free_deref_fetch_param(arg->fetch.data); - else if (CHECK_FETCH_FUNCS(symbol, arg->fetch.fn)) - free_symbol_cache(arg->fetch.data); - + kfree(arg->code); kfree(arg->name); kfree(arg->comm); } diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h index de928052926b..9d9de7535d06 100644 --- a/kernel/trace/trace_probe.h +++ b/kernel/trace/trace_probe.h @@ -91,25 +91,50 @@ static nokprobe_inline void *get_loc_data(u32 *dl, void *ent) return (u8 *)ent + get_rloc_offs(*dl); }

-/* Data fetch function type */ -typedef void (*fetch_func_t)(struct pt_regs *, void *, void *); /* Printing function type */ typedef int (*print_type_func_t)(struct trace_seq *, void *, void *);

-/* Fetch types */ -enum { - FETCH_MTD_reg = 0, - FETCH_MTD_stack, - FETCH_MTD_retval, - FETCH_MTD_comm, - FETCH_MTD_memory, - FETCH_MTD_symbol, - FETCH_MTD_deref, - FETCH_MTD_bitfield, - FETCH_MTD_file_offset, - FETCH_MTD_END, +enum fetch_op { + FETCH_OP_NOP = 0, + // Stage 1 (load) ops + FETCH_OP_REG, /* Register : .param = offset */ + FETCH_OP_STACK, /* Stack : .param = index */ + FETCH_OP_STACKP, /* Stack pointer */ + FETCH_OP_RETVAL, /* Return value */ + FETCH_OP_IMM, /* Immediate : .immediate */ + FETCH_OP_COMM, /* Current comm */ + FETCH_OP_FOFFS, /* File offset: .immediate */ + // Stage 2 (dereference) op + FETCH_OP_DEREF, /* Dereference: .offset */ + // Stage 3 (store) ops + FETCH_OP_ST_RAW, /* Raw: .size */ + FETCH_OP_ST_MEM, /* Mem: .offset, .size */ + FETCH_OP_ST_STRING, /* String: .offset, .size */ + // Stage 4 (modify) op + FETCH_OP_MOD_BF, /* Bitfield: .basesize, .lshift, .rshift */ + FETCH_OP_END, };

+struct fetch_insn { + enum fetch_op op; + union { + unsigned int param; + struct { + unsigned int size; + int offset; + }; + struct { + unsigned char basesize; + unsigned char lshift; + unsigned char rshift; + }; + unsigned long immediate; + }; +}; + +/* fetch + deref*N + store + mod + end <= 16, this allows N=12, enough */ +#define FETCH_INSN_MAX 16 + /* Fetch type information table */ struct fetch_type { const char *name; /* Name of type */ @@ -118,13 +143,6 @@ struct fetch_type { print_type_func_t print; /* Print functions */ const char *fmt; /* Fromat string */ const char *fmttype; /* Name in format file */ - /* Fetch functions */ - fetch_func_t fetch[FETCH_MTD_END]; -}; - -struct fetch_param { - fetch_func_t fn; - void *data; };

/* For defining macros, define string/string_size types */ @@ -154,66 +172,12 @@ DECLARE_BASIC_PRINT_TYPE_FUNC(x64);

DECLARE_BASIC_PRINT_TYPE_FUNC(string);

-#define FETCH_FUNC_NAME(method, type) fetch_##method##_##type - -/* Declare macro for basic types */ -#define DECLARE_FETCH_FUNC(method, type) \ -extern void FETCH_FUNC_NAME(method, type)(struct pt_regs *regs, \ - void *data, void *dest) - -#define DECLARE_BASIC_FETCH_FUNCS(method) \ -DECLARE_FETCH_FUNC(method, u8); \ -DECLARE_FETCH_FUNC(method, u16); \ -DECLARE_FETCH_FUNC(method, u32); \ -DECLARE_FETCH_FUNC(method, u64) - -DECLARE_BASIC_FETCH_FUNCS(reg); -#define fetch_reg_string NULL -#define fetch_reg_string_size NULL - -DECLARE_BASIC_FETCH_FUNCS(retval); -#define fetch_retval_string NULL -#define fetch_retval_string_size NULL - -DECLARE_BASIC_FETCH_FUNCS(symbol); -DECLARE_FETCH_FUNC(symbol, string); -DECLARE_FETCH_FUNC(symbol, string_size); - -DECLARE_BASIC_FETCH_FUNCS(deref); -DECLARE_FETCH_FUNC(deref, string); -DECLARE_FETCH_FUNC(deref, string_size); - -DECLARE_BASIC_FETCH_FUNCS(bitfield); -#define fetch_bitfield_string NULL -#define fetch_bitfield_string_size NULL - -/* comm only makes sense as a string */ -#define fetch_comm_u8 NULL -#define fetch_comm_u16 NULL -#define fetch_comm_u32 NULL -#define fetch_comm_u64 NULL -DECLARE_FETCH_FUNC(comm, string); -DECLARE_FETCH_FUNC(comm, string_size); - -/* - * Define macro for basic types - we don't need to define s* types, because - * we have to care only about bitwidth at recording time. - */ -#define DEFINE_BASIC_FETCH_FUNCS(method) \ -DEFINE_FETCH_##method(u8) \ -DEFINE_FETCH_##method(u16) \ -DEFINE_FETCH_##method(u32) \ -DEFINE_FETCH_##method(u64) - /* Default (unsigned long) fetch type */ #define __DEFAULT_FETCH_TYPE(t) x##t #define _DEFAULT_FETCH_TYPE(t) __DEFAULT_FETCH_TYPE(t) #define DEFAULT_FETCH_TYPE _DEFAULT_FETCH_TYPE(BITS_PER_LONG) #define DEFAULT_FETCH_TYPE_STR __stringify(DEFAULT_FETCH_TYPE)

-#define ASSIGN_FETCH_FUNC(method, type) \ - [FETCH_MTD_##method] = FETCH_FUNC_NAME(method, type) - #define __ASSIGN_FETCH_TYPE(_name, ptype, ftype, _size, sign, _fmttype) \ {.name = _name, \ .size = _size, \ @@ -221,17 +185,6 @@ DEFINE_FETCH_##method(u64) .print = PRINT_TYPE_FUNC_NAME(ptype), \ .fmt = PRINT_TYPE_FMT_NAME(ptype), \ .fmttype = _fmttype, \ - .fetch = { \ -ASSIGN_FETCH_FUNC(reg, ftype), \ -ASSIGN_FETCH_FUNC(stack, ftype), \ -ASSIGN_FETCH_FUNC(retval, ftype), \ -ASSIGN_FETCH_FUNC(comm, ftype), \ -ASSIGN_FETCH_FUNC(memory, ftype), \ -ASSIGN_FETCH_FUNC(symbol, ftype), \ -ASSIGN_FETCH_FUNC(deref, ftype), \ -ASSIGN_FETCH_FUNC(bitfield, ftype), \ -ASSIGN_FETCH_FUNC(file_offset, ftype), \ - } \ }

#define ASSIGN_FETCH_TYPE(ptype, ftype, sign) \ @@ -243,42 +196,13 @@ ASSIGN_FETCH_FUNC(file_offset, ftype), \

#define ASSIGN_FETCH_TYPE_END {}

-#define FETCH_TYPE_STRING 0 -#define FETCH_TYPE_STRSIZE 1 +#define FETCH_TYPE_STRING 0 +#define FETCH_TYPE_STRSIZE 1

#ifdef CONFIG_KPROBE_EVENTS -struct symbol_cache; -unsigned long update_symbol_cache(struct symbol_cache *sc); -void free_symbol_cache(struct symbol_cache *sc); -struct symbol_cache *alloc_symbol_cache(const char *sym, long offset); bool trace_kprobe_on_func_entry(struct trace_event_call *call); bool trace_kprobe_error_injectable(struct trace_event_call *call); #else -/* uprobes do not support symbol fetch methods */ -#define fetch_symbol_u8 NULL -#define fetch_symbol_u16 NULL -#define fetch_symbol_u32 NULL -#define fetch_symbol_u64 NULL -#define fetch_symbol_string NULL -#define fetch_symbol_string_size NULL - -struct symbol_cache { -}; -static inline unsigned long __used update_symbol_cache(struct symbol_cache *sc) -{ - return 0; -} - -static inline void __used free_symbol_cache(struct symbol_cache *sc) -{ -} - -static inline struct symbol_cache * __used -alloc_symbol_cache(const char *sym, long offset) -{ - return NULL; -} - static inline bool trace_kprobe_on_func_entry(struct trace_event_call *call) { return false; @@ -291,8 +215,8 @@ static inline bool trace_kprobe_error_injectable(struct trace_event_call *call) #endif /* CONFIG_KPROBE_EVENTS */

struct probe_arg { - struct fetch_param fetch; - struct fetch_param fetch_size; + struct fetch_insn *code; + bool dynamic;/* Dynamic array (string) is used */ unsigned int offset; /* Offset from argument entry */ const char *name; /* Name of this argument */ const char *comm; /* Command of this argument */ @@ -324,12 +248,6 @@ static inline bool trace_probe_is_registered(struct trace_probe *tp) return !!(tp->flags & TP_FLAG_REGISTERED); }

-static nokprobe_inline void call_fetch(struct fetch_param *fprm, - struct pt_regs *regs, void *dest) -{ - return fprm->fn(regs, fprm->data, dest); -} - /* Check the name is good for event/group/fields */ static inline bool is_good_name(const char *name) { @@ -366,68 +284,6 @@ extern void traceprobe_free_probe_arg(struct probe_arg *arg);

extern int traceprobe_split_symbol_offset(char *symbol, long *offset);

-/* Sum up total data length for dynamic arraies (strings) */ -static nokprobe_inline int -__get_data_size(struct trace_probe *tp, struct pt_regs *regs) -{ - int i, ret = 0; - u32 len; - - for (i = 0; i < tp->nr_args; i++) - if (unlikely(tp->args[i].fetch_size.fn)) { - call_fetch(&tp->args[i].fetch_size, regs, &len); - ret += len; - } - - return ret; -} - -/* Store the value of each argument */ -static nokprobe_inline void -store_trace_args(int ent_size, struct trace_probe *tp, struct pt_regs *regs, - u8 *data, int maxlen) -{ - int i; - u32 end = tp->size; - u32 *dl; /* Data (relative) location */ - - for (i = 0; i < tp->nr_args; i++) { - if (unlikely(tp->args[i].fetch_size.fn)) { - /* - * First, we set the relative location and - * maximum data length to *dl - */ - dl = (u32 *)(data + tp->args[i].offset); - *dl = make_data_rloc(maxlen, end - tp->args[i].offset); - /* Then try to fetch string or dynamic array data */ - call_fetch(&tp->args[i].fetch, regs, dl); - /* Reduce maximum length */ - end += get_rloc_len(*dl); - maxlen -= get_rloc_len(*dl); - /* Trick here, convert data_rloc to data_loc */ - *dl = convert_rloc_to_loc(*dl, - ent_size + tp->args[i].offset); - } else - /* Just fetching data normally */ - call_fetch(&tp->args[i].fetch, regs, - data + tp->args[i].offset); - } -} - -static inline int -print_probe_args(struct trace_seq *s, struct probe_arg *args, int nr_args, - u8 *data, void *field) -{ - int i; - - for (i = 0; i < nr_args; i++) { - trace_seq_printf(s, " %s=", args[i].name); - if (!args[i].type->print(s, data + args[i].offset, field)) - return -ENOMEM; - } - return 0; -} - extern int set_print_fmt(struct trace_probe *tp, bool is_return);

#ifdef CONFIG_PERF_EVENTS diff --git a/kernel/trace/trace_probe_tmpl.h b/kernel/trace/trace_probe_tmpl.h new file mode 100644 index 000000000000..c8a5272abf01 --- /dev/null +++ b/kernel/trace/trace_probe_tmpl.h @@ -0,0 +1,120 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * Traceprobe fetch helper inlines + */ + +static nokprobe_inline void +fetch_store_raw(unsigned long val, struct fetch_insn *code, void *buf) +{ + switch (code->size) { + case 1: + *(u8 *)buf = (u8)val; + break; + case 2: + *(u16 *)buf = (u16)val; + break; + case 4: + *(u32 *)buf = (u32)val; + break; + case 8: + //TBD: 32bit signed + *(u64 *)buf = (u64)val; + break; + default: + *(unsigned long *)buf = val; + } +} + +static nokprobe_inline void +fetch_apply_bitfield(struct fetch_insn *code, void *buf) +{ + switch (code->basesize) { + case 1: + *(u8 *)buf <<= code->lshift; + *(u8 *)buf >>= code->rshift; + break; + case 2: + *(u16 *)buf <<= code->lshift; + *(u16 *)buf >>= code->rshift; + break; + case 4: + *(u32 *)buf <<= code->lshift; + *(u32 *)buf >>= code->rshift; + break; + case 8: + *(u64 *)buf <<= code->lshift; + *(u64 *)buf >>= code->rshift; + break; + } +} + +/* Define this for each callsite */ +static int +process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, + void *dest, bool pre); + +/* Sum up total data length for dynamic arraies (strings) */ +static nokprobe_inline int +__get_data_size(struct trace_probe *tp, struct pt_regs *regs) +{ + struct probe_arg *arg; + int i, ret = 0; + u32 len; + + for (i = 0; i < tp->nr_args; i++) { + arg = tp->args + i; + if (unlikely(arg->dynamic)) { + process_fetch_insn(arg->code, regs, &len, true); + ret += len; + } + } + + return ret; +} + +/* Store the value of each argument */ +static nokprobe_inline void +store_trace_args(int ent_size, struct trace_probe *tp, struct pt_regs *regs, + u8 *data, int maxlen) +{ + struct probe_arg *arg; + u32 end = tp->size; + u32 *dl; /* Data (relative) location */ + int i; + + for (i = 0; i < tp->nr_args; i++) { + arg = tp->args + i; + if (unlikely(arg->dynamic)) { + /* + * First, we set the relative location and + * maximum data length to *dl + */ + dl = (u32 *)(data + arg->offset); + *dl = make_data_rloc(maxlen, end - arg->offset); + /* Then try to fetch string or dynamic array data */ + process_fetch_insn(arg->code, regs, dl, false); + /* Reduce maximum length */ + end += get_rloc_len(*dl); + maxlen -= get_rloc_len(*dl); + /* Trick here, convert data_rloc to data_loc */ + *dl = convert_rloc_to_loc(*dl, ent_size + arg->offset); + } else + /* Just fetching data normally */ + process_fetch_insn(arg->code, regs, data + arg->offset, + false); + } +} + +static inline int +print_probe_args(struct trace_seq *s, struct probe_arg *args, int nr_args, + u8 *data, void *field) +{ + int i; + + for (i = 0; i < nr_args; i++) { + trace_seq_printf(s, " %s=", args[i].name); + if (!args[i].type->print(s, data + args[i].offset, field)) + return -ENOMEM; + } + return 0; +} diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c index 887da2bb63aa..e1bc33c5cd99 100644 --- a/kernel/trace/trace_uprobe.c +++ b/kernel/trace/trace_uprobe.c @@ -27,6 +27,7 @@ #include <linux/rculist.h>

#include "trace_probe.h" +#include "trace_probe_tmpl.h"

#define UPROBE_EVENT_SYSTEM "uprobes"

@@ -109,37 +110,19 @@ static unsigned long get_user_stack_nth(struct pt_regs *regs, unsigned int n) /* * Uprobes-specific fetch functions */ -#define DEFINE_FETCH_stack(type) \ -static void FETCH_FUNC_NAME(stack, type)(struct pt_regs *regs, \ - void *offset, void *dest) \ -{ \ - *(type *)dest = (type)get_user_stack_nth(regs, \ - ((unsigned long)offset)); \ -} -DEFINE_BASIC_FETCH_FUNCS(stack) -/* No string on the stack entry */ -#define fetch_stack_string NULL -#define fetch_stack_string_size NULL - -#define DEFINE_FETCH_memory(type) \ -static void FETCH_FUNC_NAME(memory, type)(struct pt_regs *regs, \ - void *addr, void *dest) \ -{ \ - type retval; \ - void __user *vaddr = (void __force __user *) addr; \ - \ - if (copy_from_user(&retval, vaddr, sizeof(type))) \ - *(type *)dest = 0; \ - else \ - *(type *) dest = retval; \ +static nokprobe_inline int +probe_user_read(void *dest, void *src, size_t size) +{ + void __user *vaddr = (void __force __user *)src; + + return copy_from_user(dest, vaddr, size); } -DEFINE_BASIC_FETCH_FUNCS(memory) /* * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max * length and relative data location. */ -static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs, - void *addr, void *dest) +static nokprobe_inline void +fetch_store_string(unsigned long addr, void *dest) { long ret; u32 rloc = *(u32 *)dest; @@ -160,8 +143,9 @@ static void FETCH_FUNC_NAME(memory, string)(struct pt_regs *regs, } }

-static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs, - void *addr, void *dest) +/* Return the length of string -- including null terminal byte */ +static nokprobe_inline void +fetch_store_strlen(unsigned long addr, void *dest) { int len; void __user *vaddr = (void __force __user *) addr; @@ -174,7 +158,7 @@ static void FETCH_FUNC_NAME(memory, string_size)(struct pt_regs *regs, *(u32 *)dest = len; }

-static unsigned long translate_user_vaddr(void *file_offset) +static unsigned long translate_user_vaddr(unsigned long file_offset) { unsigned long base_addr; struct uprobe_dispatch_data *udd; @@ -182,21 +166,9 @@ static unsigned long translate_user_vaddr(void *file_offset) udd = (void *) current->utask->vaddr;

base_addr = udd->bp_addr - udd->tu->offset; - return base_addr + (unsigned long)file_offset; + return base_addr + file_offset; }

-#define DEFINE_FETCH_file_offset(type) \ -static void FETCH_FUNC_NAME(file_offset, type)(struct pt_regs *regs, \ - void *offset, void *dest)\ -{ \ - void *vaddr = (void *)translate_user_vaddr(offset); \ - \ - FETCH_FUNC_NAME(memory, type)(regs, vaddr, dest); \ -} -DEFINE_BASIC_FETCH_FUNCS(file_offset) -DEFINE_FETCH_file_offset(string) -DEFINE_FETCH_file_offset(string_size) - /* Fetch type information table */ static const struct fetch_type uprobes_fetch_type_table[] = { /* Special types */ @@ -221,6 +193,77 @@ static const struct fetch_type uprobes_fetch_type_table[] = { ASSIGN_FETCH_TYPE_END };

+/* Note that we don't verify it, since the code does not come from user space */ +static int +process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, + bool pre) +{ + unsigned long val; + int ret; + + /* 1st stage: get value from context */ + switch (code->op) { + case FETCH_OP_REG: + val = regs_get_register(regs, code->param); + break; + case FETCH_OP_STACK: + val = get_user_stack_nth(regs, code->param); + break; + case FETCH_OP_STACKP: + val = user_stack_pointer(regs); + break; + case FETCH_OP_RETVAL: + val = regs_return_value(regs); + break; + case FETCH_OP_IMM: + val = code->immediate; + break; + case FETCH_OP_FOFFS: + val = translate_user_vaddr(code->immediate); + break; + default: + return -EILSEQ; + } + code++; + + /* 2nd stage: dereference memory if needed */ + while (code->op == FETCH_OP_DEREF) { + ret = probe_user_read(&val, (void *)val + code->offset, + sizeof(val)); + if (ret) + return ret; + code++; + } + + /* 3rd stage: store value to buffer */ + switch (code->op) { + case FETCH_OP_ST_RAW: + fetch_store_raw(val, code, dest); + break; + case FETCH_OP_ST_MEM: + probe_user_read(dest, (void *)val + code->offset, code->size); + break; + case FETCH_OP_ST_STRING: + if (pre) + fetch_store_strlen(val + code->offset, dest); + else + fetch_store_string(val + code->offset, dest); + break; + default: + return -EILSEQ; + } + code++; + + /* 4th stage: modify stored value if needed */ + if (code->op == FETCH_OP_MOD_BF) { + fetch_apply_bitfield(code, dest); + code++; + } + + return code->op == FETCH_OP_END ? 0 : -EILSEQ; +} +NOKPROBE_SYMBOL(process_fetch_insn) + static inline void init_trace_uprobe_filter(struct trace_uprobe_filter *filter) { rwlock_init(&filter->rwlock);

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Cleanup string fetching routine so that returns the consumed bytes of dynamic area and store the string information as data_loc format instead of data_rloc. This simplifies the fetcharg loop.

Signed-off-by: Masami Hiramatsu mhiramat@kernel.org --- kernel/trace/trace_kprobe.c | 51 +++++++++++++++++++------------------- kernel/trace/trace_probe.h | 26 ++++--------------- kernel/trace/trace_probe_tmpl.h | 52 +++++++++++++++++--------------------- kernel/trace/trace_uprobe.c | 53 ++++++++++++++++++++------------------- 4 files changed, 82 insertions(+), 100 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 0b73b1ee82c8..927299ff191c 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -807,8 +807,8 @@ static const struct file_operations kprobe_profile_ops = { /* Kprobe specific fetch functions */

/* Return the length of string -- including null terminal byte */ -static nokprobe_inline void -fetch_store_strlen(unsigned long addr, void *dest) +static nokprobe_inline int +fetch_store_strlen(unsigned long addr) { mm_segment_t old_fs; int ret, len = 0; @@ -826,25 +826,22 @@ fetch_store_strlen(unsigned long addr, void *dest) pagefault_enable(); set_fs(old_fs);

- if (ret < 0) /* Failed to check the length */ - *(u32 *)dest = 0; - else - *(u32 *)dest = len; + return (ret < 0) ? ret : len; }

/* * Fetch a null-terminated string. Caller MUST set *(u32 *)buf with max * length and relative data location. */ -static nokprobe_inline void -fetch_store_string(unsigned long addr, void *dest) +static nokprobe_inline int +fetch_store_string(unsigned long addr, void *dest, void *base) { - int maxlen = get_rloc_len(*(u32 *)dest); - u8 *dst = get_rloc_data(dest); + int maxlen = get_loc_len(*(u32 *)dest); + u8 *dst = get_loc_data(dest, base); long ret;

if (!maxlen) - return; + return -ENOMEM;

/* * Try to get string again, since the string can be changed while @@ -854,19 +851,19 @@ fetch_store_string(unsigned long addr, void *dest)

if (ret < 0) { /* Failed to fetch string */ dst[0] = '\0'; - *(u32 *)dest = make_data_rloc(0, get_rloc_offs(*(u32 *)dest)); - } else { - *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(*(u32 *)dest)); + ret = 0; } + *(u32 *)dest = make_data_loc(ret, (void *)dst - base); + return ret; }

/* Note that we don't verify it, since the code does not come from user space */ static int process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, - bool pre) + void *base) { unsigned long val; - int ret; + int ret = 0;

/* 1st stage: get value from context */ switch (code->op) { @@ -903,6 +900,13 @@ process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, }

/* 3rd stage: store value to buffer */ + if (unlikely(!dest)) { + if (code->op == FETCH_OP_ST_STRING) + return fetch_store_strlen(val + code->offset); + else + return -EILSEQ; + } + switch (code->op) { case FETCH_OP_ST_RAW: fetch_store_raw(val, code, dest); @@ -911,10 +915,7 @@ process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, probe_kernel_read(dest, (void *)val + code->offset, code->size); break; case FETCH_OP_ST_STRING: - if (pre) - fetch_store_strlen(val + code->offset, dest); - else - fetch_store_string(val + code->offset, dest); + ret = fetch_store_string(val + code->offset, dest, base); break; default: return -EILSEQ; @@ -927,7 +928,7 @@ process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, code++; }

- return code->op == FETCH_OP_END ? 0 : -EILSEQ; + return code->op == FETCH_OP_END ? ret : -EILSEQ; } NOKPROBE_SYMBOL(process_fetch_insn)

@@ -962,7 +963,7 @@ __kprobe_trace_func(struct trace_kprobe *tk, struct pt_regs *regs,

entry = ring_buffer_event_data(event); entry->ip = (unsigned long)tk->rp.kp.addr; - store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize); + store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);

event_trigger_unlock_commit_regs(trace_file, buffer, event, entry, irq_flags, pc, regs); @@ -1011,7 +1012,7 @@ __kretprobe_trace_func(struct trace_kprobe *tk, struct kretprobe_instance *ri, entry = ring_buffer_event_data(event); entry->func = (unsigned long)tk->rp.kp.addr; entry->ret_ip = (unsigned long)ri->ret_addr; - store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize); + store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize);

event_trigger_unlock_commit_regs(trace_file, buffer, event, entry, irq_flags, pc, regs); @@ -1162,7 +1163,7 @@ kprobe_perf_func(struct trace_kprobe *tk, struct pt_regs *regs)

entry->ip = (unsigned long)tk->rp.kp.addr; memset(&entry[1], 0, dsize); - store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize); + store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, head, NULL); return 0; @@ -1198,7 +1199,7 @@ kretprobe_perf_func(struct trace_kprobe *tk, struct kretprobe_instance *ri,

entry->func = (unsigned long)tk->rp.kp.addr; entry->ret_ip = (unsigned long)ri->ret_addr; - store_trace_args(sizeof(*entry), &tk->tp, regs, (u8 *)&entry[1], dsize); + store_trace_args(&entry[1], &tk->tp, regs, sizeof(*entry), dsize); perf_trace_buf_submit(entry, size, rctx, call->event.type, 1, regs, head, NULL); } diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h index 89d853ef5174..d1b8bd74bf56 100644 --- a/kernel/trace/trace_probe.h +++ b/kernel/trace/trace_probe.h @@ -66,29 +66,15 @@ #define TP_FLAG_PROFILE 2 #define TP_FLAG_REGISTERED 4

+/* data_loc: data location, compatible with u32 */ +#define make_data_loc(len, offs) \ + (((u32)(len) << 16) | ((u32)(offs) & 0xffff)) +#define get_loc_len(dl) ((u32)(dl) >> 16) +#define get_loc_offs(dl) ((u32)(dl) & 0xffff)

-/* data_rloc: data relative location, compatible with u32 */ -#define make_data_rloc(len, roffs) \ - (((u32)(len) << 16) | ((u32)(roffs) & 0xffff)) -#define get_rloc_len(dl) ((u32)(dl) >> 16) -#define get_rloc_offs(dl) ((u32)(dl) & 0xffff) - -/* - * Convert data_rloc to data_loc: - * data_rloc stores the offset from data_rloc itself, but data_loc - * stores the offset from event entry. - */ -#define convert_rloc_to_loc(dl, offs) ((u32)(dl) + (offs)) - -static nokprobe_inline void *get_rloc_data(u32 *dl) -{ - return (u8 *)dl + get_rloc_offs(*dl); -} - -/* For data_loc conversion */ static nokprobe_inline void *get_loc_data(u32 *dl, void *ent) { - return (u8 *)ent + get_rloc_offs(*dl); + return (u8 *)ent + get_loc_offs(*dl); }

/* Printing function type */ diff --git a/kernel/trace/trace_probe_tmpl.h b/kernel/trace/trace_probe_tmpl.h index c8a5272abf01..d9aebd395a9d 100644 --- a/kernel/trace/trace_probe_tmpl.h +++ b/kernel/trace/trace_probe_tmpl.h @@ -48,24 +48,28 @@ fetch_apply_bitfield(struct fetch_insn *code, void *buf) } }

-/* Define this for each callsite */ +/* + * This must be defined for each callsite. + * Return consumed dynamic data size (>= 0), or error (< 0). + * If dest is NULL, don't store result and return required dynamic data size. + */ static int process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, - void *dest, bool pre); + void *dest, void *base);

/* Sum up total data length for dynamic arraies (strings) */ static nokprobe_inline int __get_data_size(struct trace_probe *tp, struct pt_regs *regs) { struct probe_arg *arg; - int i, ret = 0; - u32 len; + int i, len, ret = 0;

for (i = 0; i < tp->nr_args; i++) { arg = tp->args + i; if (unlikely(arg->dynamic)) { - process_fetch_insn(arg->code, regs, &len, true); - ret += len; + len = process_fetch_insn(arg->code, regs, NULL, NULL); + if (len > 0) + ret += len; } }

@@ -74,34 +78,24 @@ __get_data_size(struct trace_probe *tp, struct pt_regs *regs)

/* Store the value of each argument */ static nokprobe_inline void -store_trace_args(int ent_size, struct trace_probe *tp, struct pt_regs *regs, - u8 *data, int maxlen) +store_trace_args(void *data, struct trace_probe *tp, struct pt_regs *regs, + int header_size, int maxlen) { struct probe_arg *arg; - u32 end = tp->size; - u32 *dl; /* Data (relative) location */ - int i; + void *base = data - header_size; + void *dyndata = data + tp->size; + u32 *dl; /* Data location */ + int ret, i;

for (i = 0; i < tp->nr_args; i++) { arg = tp->args + i; - if (unlikely(arg->dynamic)) { - /* - * First, we set the relative location and - * maximum data length to *dl - */ - dl = (u32 *)(data + arg->offset); - *dl = make_data_rloc(maxlen, end - arg->offset); - /* Then try to fetch string or dynamic array data */ - process_fetch_insn(arg->code, regs, dl, false); - /* Reduce maximum length */ - end += get_rloc_len(*dl); - maxlen -= get_rloc_len(*dl); - /* Trick here, convert data_rloc to data_loc */ - *dl = convert_rloc_to_loc(*dl, ent_size + arg->offset); - } else - /* Just fetching data normally */ - process_fetch_insn(arg->code, regs, data + arg->offset, - false); + dl = data + arg->offset; + /* Point the dynamic data area if needed */ + if (unlikely(arg->dynamic)) + *dl = make_data_loc(maxlen, dyndata - base); + ret = process_fetch_insn(arg->code, regs, dl, base); + if (ret > 0) + dyndata += ret; } }

diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c index 9fc0123c721f..de4f91bb313a 100644 --- a/kernel/trace/trace_uprobe.c +++ b/kernel/trace/trace_uprobe.c @@ -121,41 +121,38 @@ probe_user_read(void *dest, void *src, size_t size) * Fetch a null-terminated string. Caller MUST set *(u32 *)dest with max * length and relative data location. */ -static nokprobe_inline void -fetch_store_string(unsigned long addr, void *dest) +static nokprobe_inline int +fetch_store_string(unsigned long addr, void *dest, void *base) { long ret; - u32 rloc = *(u32 *)dest; - int maxlen = get_rloc_len(rloc); - u8 *dst = get_rloc_data(dest); + u32 loc = *(u32 *)dest; + int maxlen = get_loc_len(loc); + u8 *dst = get_loc_data(dest, base); void __user *src = (void __force __user *) addr;

if (!maxlen) - return; + return -ENOMEM;

ret = strncpy_from_user(dst, src, maxlen);

if (ret < 0) { /* Failed to fetch string */ - ((u8 *)get_rloc_data(dest))[0] = '\0'; - *(u32 *)dest = make_data_rloc(0, get_rloc_offs(rloc)); - } else { - *(u32 *)dest = make_data_rloc(ret, get_rloc_offs(rloc)); + dst[0] = '\0'; + ret = 0; } + *(u32 *)dest = make_data_loc(ret, (void *)dst - base); + return ret; }

/* Return the length of string -- including null terminal byte */ -static nokprobe_inline void -fetch_store_strlen(unsigned long addr, void *dest) +static nokprobe_inline int +fetch_store_strlen(unsigned long addr) { int len; void __user *vaddr = (void __force __user *) addr;

len = strnlen_user(vaddr, MAX_STRING_SIZE);

- if (len == 0 || len > MAX_STRING_SIZE) /* Failed to check length */ - *(u32 *)dest = 0; - else - *(u32 *)dest = len; + return (len > MAX_STRING_SIZE) ? 0 : len; }

static unsigned long translate_user_vaddr(unsigned long file_offset) @@ -172,10 +169,10 @@ static unsigned long translate_user_vaddr(unsigned long file_offset) /* Note that we don't verify it, since the code does not come from user space */ static int process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, - bool pre) + void *base) { unsigned long val; - int ret; + int ret = 0;

/* 1st stage: get value from context */ switch (code->op) { @@ -212,18 +209,22 @@ process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, }

/* 3rd stage: store value to buffer */ + if (unlikely(!dest)) { + if (code->op == FETCH_OP_ST_STRING) + return fetch_store_strlen(val + code->offset); + else + return -EILSEQ; + } + switch (code->op) { case FETCH_OP_ST_RAW: fetch_store_raw(val, code, dest); break; case FETCH_OP_ST_MEM: - probe_user_read(dest, (void *)val + code->offset, code->size); + probe_kernel_read(dest, (void *)val + code->offset, code->size); break; case FETCH_OP_ST_STRING: - if (pre) - fetch_store_strlen(val + code->offset, dest); - else - fetch_store_string(val + code->offset, dest); + ret = fetch_store_string(val + code->offset, dest, base); break; default: return -EILSEQ; @@ -236,7 +237,7 @@ process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, code++; }

- return code->op == FETCH_OP_END ? 0 : -EILSEQ; + return code->op == FETCH_OP_END ? ret : -EILSEQ; } NOKPROBE_SYMBOL(process_fetch_insn)

@@ -1242,7 +1243,7 @@ static int uprobe_dispatcher(struct uprobe_consumer *con, struct pt_regs *regs) esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));

ucb = uprobe_buffer_get(); - store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize); + store_trace_args(ucb->buf, &tu->tp, regs, esize, dsize);

if (tu->tp.flags & TP_FLAG_TRACE) ret |= uprobe_trace_func(tu, regs, ucb, dsize); @@ -1277,7 +1278,7 @@ static int uretprobe_dispatcher(struct uprobe_consumer *con, esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));

ucb = uprobe_buffer_get(); - store_trace_args(esize, &tu->tp, regs, ucb->buf, dsize); + store_trace_args(ucb->buf, &tu->tp, regs, esize, dsize);

if (tu->tp.flags & TP_FLAG_TRACE) uretprobe_trace_func(tu, func, regs, ucb, dsize);

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Unify the fetch_insn bottom process (from stage 2: dereference indirect data) from kprobe and uprobe events, since those are mostly same.

Signed-off-by: Masami Hiramatsu mhiramat@kernel.org --- kernel/trace/trace_kprobe.c | 47 +++++---------------------------- kernel/trace/trace_probe_tmpl.h | 55 ++++++++++++++++++++++++++++++++++++++- kernel/trace/trace_uprobe.c | 43 +----------------------------- 3 files changed, 63 insertions(+), 82 deletions(-)

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 7d48ae5f0617..b564d38810b7 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -857,13 +857,18 @@ fetch_store_string(unsigned long addr, void *dest, void *base) return ret; }

+static nokprobe_inline int +probe_mem_read(void *dest, void *src, size_t size) +{ + return probe_kernel_read(dest, src, size); +} + /* Note that we don't verify it, since the code does not come from user space */ static int process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, void *base) { unsigned long val; - int ret = 0;

/* 1st stage: get value from context */ switch (code->op) { @@ -890,45 +895,7 @@ process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, } code++;

- /* 2nd stage: dereference memory if needed */ - while (code->op == FETCH_OP_DEREF) { - ret = probe_kernel_read(&val, (void *)val + code->offset, - sizeof(val)); - if (ret) - return ret; - code++; - } - - /* 3rd stage: store value to buffer */ - if (unlikely(!dest)) { - if (code->op == FETCH_OP_ST_STRING) - return fetch_store_strlen(val + code->offset); - else - return -EILSEQ; - } - - switch (code->op) { - case FETCH_OP_ST_RAW: - fetch_store_raw(val, code, dest); - break; - case FETCH_OP_ST_MEM: - probe_kernel_read(dest, (void *)val + code->offset, code->size); - break; - case FETCH_OP_ST_STRING: - ret = fetch_store_string(val + code->offset, dest, base); - break; - default: - return -EILSEQ; - } - code++; - - /* 4th stage: modify stored value if needed */ - if (code->op == FETCH_OP_MOD_BF) { - fetch_apply_bitfield(code, dest); - code++; - } - - return code->op == FETCH_OP_END ? ret : -EILSEQ; + return process_fetch_insn_bottom(code, val, dest, base); } NOKPROBE_SYMBOL(process_fetch_insn)

diff --git a/kernel/trace/trace_probe_tmpl.h b/kernel/trace/trace_probe_tmpl.h index d9aebd395a9d..32ae2fc78190 100644 --- a/kernel/trace/trace_probe_tmpl.h +++ b/kernel/trace/trace_probe_tmpl.h @@ -49,13 +49,66 @@ fetch_apply_bitfield(struct fetch_insn *code, void *buf) }

/* - * This must be defined for each callsite. + * These functions must be defined for each callsite. * Return consumed dynamic data size (>= 0), or error (< 0). * If dest is NULL, don't store result and return required dynamic data size. */ static int process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, void *base); +static nokprobe_inline int fetch_store_strlen(unsigned long addr); +static nokprobe_inline int +fetch_store_string(unsigned long addr, void *dest, void *base); +static nokprobe_inline int +probe_mem_read(void *dest, void *src, size_t size); + +/* From the 2nd stage, routine is same */ +static nokprobe_inline int +process_fetch_insn_bottom(struct fetch_insn *code, unsigned long val, + void *dest, void *base) +{ + int ret = 0; + + /* 2nd stage: dereference memory if needed */ + while (code->op == FETCH_OP_DEREF) { + ret = probe_mem_read(&val, (void *)val + code->offset, + sizeof(val)); + if (ret) + return ret; + code++; + } + + /* 3rd stage: store value to buffer */ + if (unlikely(!dest)) { + if (code->op == FETCH_OP_ST_STRING) + return fetch_store_strlen(val + code->offset); + else + return -EILSEQ; + } + + switch (code->op) { + case FETCH_OP_ST_RAW: + fetch_store_raw(val, code, dest); + break; + case FETCH_OP_ST_MEM: + probe_mem_read(dest, (void *)val + code->offset, code->size); + break; + case FETCH_OP_ST_STRING: + ret = fetch_store_string(val + code->offset, dest, base); + break; + default: + return -EILSEQ; + } + code++; + + /* 4th stage: modify stored value if needed */ + if (code->op == FETCH_OP_MOD_BF) { + fetch_apply_bitfield(code, dest); + code++; + } + + return code->op == FETCH_OP_END ? ret : -EILSEQ; +}

/* Sum up total data length for dynamic arraies (strings) */ static nokprobe_inline int diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c index fafd48310823..64c1fbe087a1 100644 --- a/kernel/trace/trace_uprobe.c +++ b/kernel/trace/trace_uprobe.c @@ -111,7 +111,7 @@ static unsigned long get_user_stack_nth(struct pt_regs *regs, unsigned int n) * Uprobes-specific fetch functions */ static nokprobe_inline int -probe_user_read(void *dest, void *src, size_t size) +probe_mem_read(void *dest, void *src, size_t size) { void __user *vaddr = (void __force __user *)src;

@@ -172,7 +172,6 @@ process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, void *base) { unsigned long val; - int ret = 0;

/* 1st stage: get value from context */ switch (code->op) { @@ -199,45 +198,7 @@ process_fetch_insn(struct fetch_insn *code, struct pt_regs *regs, void *dest, } code++;

- /* 2nd stage: dereference memory if needed */ - while (code->op == FETCH_OP_DEREF) { - ret = probe_user_read(&val, (void *)val + code->offset, - sizeof(val)); - if (ret) - return ret; - code++; - } - - /* 3rd stage: store value to buffer */ - if (unlikely(!dest)) { - if (code->op == FETCH_OP_ST_STRING) - return fetch_store_strlen(val + code->offset); - else - return -EILSEQ; - } - - switch (code->op) { - case FETCH_OP_ST_RAW: - fetch_store_raw(val, code, dest); - break; - case FETCH_OP_ST_MEM: - probe_kernel_read(dest, (void *)val + code->offset, code->size); - break; - case FETCH_OP_ST_STRING: - ret = fetch_store_string(val + code->offset, dest, base); - break; - default: - return -EILSEQ; - } - code++; - - /* 4th stage: modify stored value if needed */ - if (code->op == FETCH_OP_MOD_BF) { - fetch_apply_bitfield(code, dest); - code++; - } - - return code->op == FETCH_OP_END ? ret : -EILSEQ; + return process_fetch_insn_bottom(code, val, dest, base); } NOKPROBE_SYMBOL(process_fetch_insn)

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Add regs_get_argument() which returns N th argument of the function call. Note that this chooses most probably assignment, in some case it can be incorrect (e.g. passing data structure or floating point etc.)

This is expected to be called from kprobes or ftrace with regs where the top of stack is the return address.

Signed-off-by: Masami Hiramatsu mhiramat@kernel.org --- arch/Kconfig | 7 +++++++ arch/x86/Kconfig | 1 + arch/x86/include/asm/ptrace.h | 38 ++++++++++++++++++++++++++++++++++++++ 3 files changed, 46 insertions(+)

diff --git a/arch/Kconfig b/arch/Kconfig index 76c0b54443b1..4126ad4b122c 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -272,6 +272,13 @@ config HAVE_REGS_AND_STACK_ACCESS_API declared in asm/ptrace.h For example the kprobes-based event tracer needs this API.

+config HAVE_FUNCTION_ARG_ACCESS_API + bool + help + This symbol should be selected by an architecure if it supports + the API needed to access function arguments from pt_regs, + declared in asm/ptrace.h + config HAVE_CLK bool help diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 18233e459bff..5dde520da3b5 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -176,6 +176,7 @@ config X86 select HAVE_PERF_USER_STACK_DUMP select HAVE_RCU_TABLE_FREE select HAVE_REGS_AND_STACK_ACCESS_API + select HAVE_FUNCTION_ARG_ACCESS_API select HAVE_RELIABLE_STACKTRACE if X86_64 && UNWINDER_FRAME_POINTER && STACK_VALIDATION select HAVE_STACK_VALIDATION if X86_64 select HAVE_SYSCALL_TRACEPOINTS diff --git a/arch/x86/include/asm/ptrace.h b/arch/x86/include/asm/ptrace.h index 6de1fd3d0097..c2304b25e2fd 100644 --- a/arch/x86/include/asm/ptrace.h +++ b/arch/x86/include/asm/ptrace.h @@ -256,6 +256,44 @@ static inline unsigned long regs_get_kernel_stack_nth(struct pt_regs *regs, return 0; }

+/** + * regs_get_kernel_argument() - get Nth function argument in kernel + * @regs: pt_regs of that context + * @n: function argument number (start from 0) + * + * regs_get_argument() returns @n th argument of the function call. + * Note that this chooses most probably assignment, in some case + * it can be incorrect. + * This is expected to be called from kprobes or ftrace with regs + * where the top of stack is the return address. + */ +static inline unsigned long regs_get_kernel_argument(struct pt_regs *regs, + unsigned int n) +{ + static const unsigned int argument_offs[] = { +#ifdef __i386__ + offsetof(struct pt_regs, ax), + offsetof(struct pt_regs, cx), + offsetof(struct pt_regs, dx), +#define NR_REG_ARGUMENTS 3 +#else + offsetof(struct pt_regs, di), + offsetof(struct pt_regs, si), + offsetof(struct pt_regs, dx), + offsetof(struct pt_regs, cx), + offsetof(struct pt_regs, r8), + offsetof(struct pt_regs, r9), +#define NR_REG_ARGUMENTS 6 +#endif + }; + + if (n >= NR_REG_ARGUMENTS) { + n -= NR_REG_ARGUMENTS - 1; + return regs_get_kernel_stack_nth(regs, n); + } else + return regs_get_register(regs, argument_offs[n]); +} + #define arch_has_single_step() (1) #ifdef CONFIG_X86_DEBUGCTLMSR #define arch_has_block_step() (1)

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Add array type support for probe events. This allows user to get arraied types from memory address. The array type syntax is

TYPE[N]

Where TYPE is one of types (u8/16/32/64,s8/16/32/64, x8/16/32/64, symbol, string) and N is a fixed value less than 64.

The string array type is a bit different from other types. For other base types, <base-type>[1] is equal to <base-type> (e.g. +0(%di):x32[1] is same as +0(%di):x32.) But string[1] is not equal to string. The string type itself represents "char array", but string array type represents "char * array". So, for example, +0(%di):string[1] is equal to +0(+0(%di)):string.

Signed-off-by: Masami Hiramatsu mhiramat@kernel.org --- Changes in v4: - Fix to use calculated size correctly for field definition. (Thank you Namhyung!) Changes in v2: - Add array description in README file - Fix to init s3 code out of loop. - Fix to proceed code when the last code is OP_ARRAY. - Add string array type and bitfield array type. --- Documentation/trace/kprobetrace.txt | 13 ++++ kernel/trace/trace.c | 3 + kernel/trace/trace_probe.c | 130 +++++++++++++++++++++++++++-------- kernel/trace/trace_probe.h | 14 ++++ kernel/trace/trace_probe_tmpl.h | 63 +++++++++++++++-- 5 files changed, 183 insertions(+), 40 deletions(-)

diff --git a/Documentation/trace/kprobetrace.txt b/Documentation/trace/kprobetrace.txt index 1d082f8ffeee..8bf752dfc072 100644 --- a/Documentation/trace/kprobetrace.txt +++ b/Documentation/trace/kprobetrace.txt @@ -65,9 +65,22 @@ in decimal ('s' and 'u') or hexadecimal ('x'). Without type casting, 'x32' or 'x64' is used depends on the architecture (e.g. x86-32 uses x32, and x86-64 uses x64).

+These value types can be an array. To record array data, you can add '[N]' +(where N is a fixed number, less than 64) to the base type. +E.g. 'x16[4]' means an array of x16 (2bytes hex) with 4 elements. +Note that the array can be applied to memory type fetchargs, you can not +apply it to registers/stack-entries etc. (for example, '$stack1:x8[8]' is +wrong, but '+8($stack):x8[8]' is OK.) + String type is a special type, which fetches a "null-terminated" string from kernel space. This means it will fail and store NULL if the string container has been paged out. +The string array type is a bit different from other types. For other base +types, <base-type>[1] is equal to <base-type> (e.g. +0(%di):x32[1] is same +as +0(%di):x32.) But string[1] is not equal to string. The string type itself +represents "char array", but string array type represents "char * array". +So, for example, +0(%di):string[1] is equal to +0(+0(%di)):string. + Bitfield is another special type, which takes 3 parameters, bit-width, bit- offset, and container-size (usually 32). The syntax is;

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index bcd1fd87082d..b7c6698265e5 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4614,7 +4614,8 @@ static const char readme_msg[] = "\t $stack<index>, $stack, $retval, $comm\n" #endif "\t type: s8/16/32/64, u8/16/32/64, x8/16/32/64, string, symbol,\n" - "\t b<bit-width>@<bit-offset>/<container-size>\n" + "\t b<bit-width>@<bit-offset>/<container-size>,\n" + "\t <type>[<array-size>]\n" #endif " events/\t\t- Directory containing all trace event subsystems:\n" " enable\t\t- Write 0/1 to enable/disable tracing of all events\n" diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c index 9458800f394a..0e185050e492 100644 --- a/kernel/trace/trace_probe.c +++ b/kernel/trace/trace_probe.c @@ -363,9 +363,9 @@ static int __parse_bitfield_probe_arg(const char *bf, int traceprobe_parse_probe_arg(char *arg, ssize_t *size, struct probe_arg *parg, unsigned int flags) { - struct fetch_insn *code, *tmp = NULL; - const char *t; - int ret; + struct fetch_insn *code, *scode, *tmp = NULL; + char *t, *t2; + int ret, len;

if (strlen(arg) > MAX_ARGSTR_LEN) { pr_info("Argument is too long.: %s\n", arg); @@ -376,24 +376,42 @@ int traceprobe_parse_probe_arg(char *arg, ssize_t *size, pr_info("Failed to allocate memory for command '%s'.\n", arg); return -ENOMEM; } - t = strchr(parg->comm, ':'); + t = strchr(arg, ':'); if (t) { - arg[t - parg->comm] = '\0'; - t++; + *t = '\0'; + t2 = strchr(++t, '['); + if (t2) { + *t2 = '\0'; + parg->count = simple_strtoul(t2 + 1, &t2, 0); + if (strcmp(t2, "]") || parg->count == 0) + return -EINVAL; + if (parg->count > MAX_ARRAY_LEN) + return -E2BIG; + } } /* * The default type of $comm should be "string", and it can't be * dereferenced. */ if (!t && strcmp(arg, "$comm") == 0) - t = "string"; - parg->type = find_fetch_type(t); + parg->type = find_fetch_type("string"); + else + parg->type = find_fetch_type(t); if (!parg->type) { pr_info("Unsupported type: %s\n", t); return -EINVAL; } parg->offset = *size; - *size += parg->type->size; + *size += parg->type->size * (parg->count ?: 1); + + if (parg->count) { + len = strlen(parg->type->fmttype) + 6; + parg->fmt = kmalloc(len, GFP_KERNEL); + if (!parg->fmt) + return -ENOMEM; + snprintf(parg->fmt, len, "%s[%d]", parg->type->fmttype, + parg->count); + }

code = tmp = kzalloc(sizeof(*code) * FETCH_INSN_MAX, GFP_KERNEL); if (!code) @@ -413,10 +431,20 @@ int traceprobe_parse_probe_arg(char *arg, ssize_t *size, ret = -EINVAL; goto fail; } - /* Since IMM or COMM must be the 1st insn, this is safe */ - if (code->op == FETCH_OP_IMM || code->op == FETCH_OP_COMM) + if (code->op != FETCH_OP_DEREF || parg->count) { + /* + * IMM and COMM is pointing actual address, those must + * be kept, and if parg->count != 0, this is an array + * of string pointers instead of string address itself. + */ code++; + if (code->op != FETCH_OP_NOP) { + ret = -E2BIG; + goto fail; + } + } code->op = FETCH_OP_ST_STRING; /* In DEREF case, replace it */ + code->size = parg->type->size; parg->dynamic = true; } else if (code->op == FETCH_OP_DEREF) { code->op = FETCH_OP_ST_MEM; @@ -430,12 +458,29 @@ int traceprobe_parse_probe_arg(char *arg, ssize_t *size, code->op = FETCH_OP_ST_RAW; code->size = parg->type->size; } + scode = code; /* Modify operation */ if (t != NULL) { ret = __parse_bitfield_probe_arg(t, parg->type, &code); if (ret) goto fail; } + /* Loop(Array) operation */ + if (parg->count) { + if (scode->op != FETCH_OP_ST_MEM && + scode->op != FETCH_OP_ST_STRING) { + pr_info("array only accepts memory or address\n"); + ret = -EINVAL; + goto fail; + } + code++; + if (code->op != FETCH_OP_NOP) { + ret = -E2BIG; + goto fail; + } + code->op = FETCH_OP_LP_ARRAY; + code->param = parg->count; + } code++; code->op = FETCH_OP_END;

@@ -474,14 +519,17 @@ void traceprobe_free_probe_arg(struct probe_arg *arg) kfree(arg->code); kfree(arg->name); kfree(arg->comm); + kfree(arg->fmt); }

+/* When len=0, we just calculate the needed length */ +#define LEN_OR_ZERO (len ? len - pos : 0) static int __set_print_fmt(struct trace_probe *tp, char *buf, int len, bool is_return) { - int i; + struct probe_arg *parg; + int i, j; int pos = 0; - const char *fmt, *arg;

if (!is_return) { @@ -492,33 +540,49 @@ static int __set_print_fmt(struct trace_probe *tp, char *buf, int len, arg = "REC->" FIELD_STRING_FUNC ", REC->" FIELD_STRING_RETIP; }

- /* When len=0, we just calculate the needed length */ -#define LEN_OR_ZERO (len ? len - pos : 0) - pos += snprintf(buf + pos, LEN_OR_ZERO, ""%s", fmt);

for (i = 0; i < tp->nr_args; i++) { - pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=%s", - tp->args[i].name, tp->args[i].type->fmt); + parg = tp->args + i; + pos += snprintf(buf + pos, LEN_OR_ZERO, " %s=", parg->name); + if (parg->count) { + pos += snprintf(buf + pos, LEN_OR_ZERO, "{%s", + parg->type->fmt); + for (j = 1; j < parg->count; j++) + pos += snprintf(buf + pos, LEN_OR_ZERO, ",%s", + parg->type->fmt); + pos += snprintf(buf + pos, LEN_OR_ZERO, "}"); + } else + pos += snprintf(buf + pos, LEN_OR_ZERO, "%s", + parg->type->fmt); }

pos += snprintf(buf + pos, LEN_OR_ZERO, "", %s", arg);

for (i = 0; i < tp->nr_args; i++) { - if (strcmp(tp->args[i].type->name, "string") == 0) + parg = tp->args + i; + if (parg->count) { + if (strcmp(parg->type->name, "string") == 0) + fmt = ", __get_str(%s[%d])"; + else + fmt = ", REC->%s[%d]"; + for (j = 0; j < parg->count; j++) + pos += snprintf(buf + pos, LEN_OR_ZERO, + fmt, parg->name, j); + } else { + if (strcmp(parg->type->name, "string") == 0) + fmt = ", __get_str(%s)"; + else + fmt = ", REC->%s"; pos += snprintf(buf + pos, LEN_OR_ZERO, - ", __get_str(%s)", - tp->args[i].name); - else - pos += snprintf(buf + pos, LEN_OR_ZERO, ", REC->%s", - tp->args[i].name); + fmt, parg->name); + } }

-#undef LEN_OR_ZERO - /* return the length of print_fmt */ return pos; } +#undef LEN_OR_ZERO

int traceprobe_set_print_fmt(struct trace_probe *tp, bool is_return) { @@ -546,11 +610,15 @@ int traceprobe_define_arg_fields(struct trace_event_call *event_call, /* Set argument names as fields */ for (i = 0; i < tp->nr_args; i++) { struct probe_arg *parg = &tp->args[i]; - - ret = trace_define_field(event_call, parg->type->fmttype, - parg->name, - offset + parg->offset, - parg->type->size, + const char *fmt = parg->type->fmttype; + int size = parg->type->size; + + if (parg->fmt) + fmt = parg->fmt; + if (parg->count) + size *= parg->count; + ret = trace_define_field(event_call, fmt, parg->name, + offset + parg->offset, size, parg->type->is_signed, FILTER_OTHER); if (ret) diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h index ff91faf70887..d256a19ee6d1 100644 --- a/kernel/trace/trace_probe.h +++ b/kernel/trace/trace_probe.h @@ -43,6 +43,7 @@

#define MAX_TRACE_ARGS 128 #define MAX_ARGSTR_LEN 63 +#define MAX_ARRAY_LEN 64 #define MAX_STRING_SIZE PATH_MAX

/* Reserved field names */ @@ -78,6 +79,14 @@ static nokprobe_inline void *get_loc_data(u32 *dl, void *ent) return (u8 *)ent + get_loc_offs(*dl); }

+static nokprobe_inline u32 update_data_loc(u32 loc, int consumed) +{ + u32 maxlen = get_loc_len(loc); + u32 offset = get_loc_offs(loc); + + return make_data_loc(maxlen - consumed, offset + consumed); +} + /* Printing function type */ typedef int (*print_type_func_t)(struct trace_seq *, void *, void *);

@@ -100,6 +109,8 @@ enum fetch_op { FETCH_OP_ST_STRING, /* String: .offset, .size */ // Stage 4 (modify) op FETCH_OP_MOD_BF, /* Bitfield: .basesize, .lshift, .rshift */ + // Stage 5 (loop) op + FETCH_OP_LP_ARRAY, /* Array: .param = loop count */ FETCH_OP_END, };

@@ -189,6 +200,7 @@ DECLARE_BASIC_PRINT_TYPE_FUNC(symbol); _ASSIGN_FETCH_TYPE(#ptype, ptype, ftype, sizeof(ftype), sign, atype)

#define ASSIGN_FETCH_TYPE_END {} +#define MAX_ARRAY_LEN 64

#ifdef CONFIG_KPROBE_EVENTS bool trace_kprobe_on_func_entry(struct trace_event_call *call); @@ -209,8 +221,10 @@ struct probe_arg { struct fetch_insn *code; bool dynamic;/* Dynamic array (string) is used */ unsigned int offset; /* Offset from argument entry */ + unsigned int count; /* Array count */ const char *name; /* Name of this argument */ const char *comm; /* Command of this argument */ + char *fmt; /* Format string if needed */ const struct fetch_type *type; /* Type of this argument */ };

diff --git a/kernel/trace/trace_probe_tmpl.h b/kernel/trace/trace_probe_tmpl.h index 32ae2fc78190..edc09f2cd6b2 100644 --- a/kernel/trace/trace_probe_tmpl.h +++ b/kernel/trace/trace_probe_tmpl.h @@ -67,10 +67,15 @@ static nokprobe_inline int process_fetch_insn_bottom(struct fetch_insn *code, unsigned long val, void *dest, void *base) { - int ret = 0; + struct fetch_insn *s3 = NULL; + int total = 0, ret = 0, i = 0; + u32 loc = 0; + unsigned long lval = val;

+stage2: /* 2nd stage: dereference memory if needed */ while (code->op == FETCH_OP_DEREF) { + lval = val; ret = probe_mem_read(&val, (void *)val + code->offset, sizeof(val)); if (ret) @@ -78,11 +83,15 @@ process_fetch_insn_bottom(struct fetch_insn *code, unsigned long val, code++; }

+ s3 = code; +stage3: /* 3rd stage: store value to buffer */ if (unlikely(!dest)) { - if (code->op == FETCH_OP_ST_STRING) - return fetch_store_strlen(val + code->offset); - else + if (code->op == FETCH_OP_ST_STRING) { + ret += fetch_store_strlen(val + code->offset); + code++; + goto array; + } else return -EILSEQ; }

@@ -94,6 +103,7 @@ process_fetch_insn_bottom(struct fetch_insn *code, unsigned long val, probe_mem_read(dest, (void *)val + code->offset, code->size); break; case FETCH_OP_ST_STRING: + loc = *(u32 *)dest; ret = fetch_store_string(val + code->offset, dest, base); break; default: @@ -107,6 +117,29 @@ process_fetch_insn_bottom(struct fetch_insn *code, unsigned long val, code++; }

+array: + /* the last stage: Loop on array */ + if (code->op == FETCH_OP_LP_ARRAY) { + total += ret; + if (++i < code->param) { + code = s3; + if (s3->op != FETCH_OP_ST_STRING) { + dest += s3->size; + val += s3->size; + goto stage3; + } + code--; + val = lval + sizeof(char *); + if (dest) { + dest += sizeof(u32); + *(u32 *)dest = update_data_loc(loc, ret); + } + goto stage2; + } + code++; + ret = total; + } + return code->op == FETCH_OP_END ? ret : -EILSEQ; }

@@ -156,12 +189,26 @@ static inline int print_probe_args(struct trace_seq *s, struct probe_arg *args, int nr_args, u8 *data, void *field) { - int i; + void *p; + int i, j;

for (i = 0; i < nr_args; i++) { - trace_seq_printf(s, " %s=", args[i].name); - if (!args[i].type->print(s, data + args[i].offset, field)) - return -ENOMEM; + struct probe_arg *a = args + i; + + trace_seq_printf(s, " %s=", a->name); + if (likely(!a->count)) { + if (!a->type->print(s, data + a->offset, field)) + return -ENOMEM; + continue; + } + trace_seq_putc(s, '{'); + p = data + a->offset; + for (j = 0; j < a->count; j++) { + if (!a->type->print(s, p, field)) + return -ENOMEM; + trace_seq_putc(s, j == a->count - 1 ? '}' : ','); + p += a->type->size; + } } return 0; }

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Add a testcase for $argN with kprobe event. This tests whether the traced data is correct or not. If the kernel doesn't support $argN (depends on arch), it skips the test as UNSUPPORTED.

Signed-off-by: Masami Hiramatsu mhiramat@kernel.org --- Changes in v5: - Fix description. --- .../ftrace/test.d/kprobe/kprobe_args_argN.tc | 25 ++++++++++++++++++++ 1 file changed, 25 insertions(+) create mode 100644 tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_argN.tc

diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_argN.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_argN.tc new file mode 100644 index 000000000000..d5c5c8c3a51e --- /dev/null +++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_args_argN.tc @@ -0,0 +1,25 @@ +#!/bin/sh +# SPDX-License-Identifier: GPL-2.0 +# description: Kprobe event argN argument + +[ -f kprobe_events ] || exit_unsupported # this is configurable + +grep -q "arg<N>" README || exit_unsupported # version issue + +echo 0 > events/enable +echo > kprobe_events + +: "Test bad pattern : arg0 is not allowed" +! echo 'p:testprobe create_trace_kprobe $arg0' > kprobe_events + +: "Test get argument" +echo 'p:testprobe create_trace_kprobe $arg1' > kprobe_events +echo 1 > events/kprobes/testprobe/enable +! echo test >> kprobe_events +tail -n 1 trace | grep -qe "testprobe.* arg1=0x1" + +! echo test test test >> kprobe_events +tail -n 1 trace | grep -qe "testprobe.* arg1=0x3" + +echo 0 > events/enable +echo > kprobe_events

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On Thu, 8 Mar 2018 17:50:51 +0900 Masami Hiramatsu mhiramat@kernel.org wrote:

Add array type support for probe events. This allows user to get arraied types from memory address. The array type syntax is

TYPE[N]

Where TYPE is one of types (u8/16/32/64,s8/16/32/64, x8/16/32/64, symbol, string) and N is a fixed value less than 64.

The string array type is a bit different from other types. For other base types, <base-type>[1] is equal to <base-type> (e.g. +0(%di):x32[1] is same as +0(%di):x32.) But string[1] is not equal to string. The string type itself represents "char array", but string array type represents "char * array". So, for example, +0(%di):string[1] is equal to +0(+0(%di)):string.

Signed-off-by: Masami Hiramatsu mhiramat@kernel.org

Changes in v4:

• Fix to use calculated size correctly for field definition. (Thank you Namhyung!)

Changes in v2:

• Add array description in README file
• Fix to init s3 code out of loop.
• Fix to proceed code when the last code is OP_ARRAY.
• Add string array type and bitfield array type.

---

Documentation/trace/kprobetrace.txt | 13 ++++ kernel/trace/trace.c | 3 + kernel/trace/trace_probe.c | 130 +++++++++++++++++++++++++++-------- kernel/trace/trace_probe.h | 14 ++++ kernel/trace/trace_probe_tmpl.h | 63 +++++++++++++++-- 5 files changed, 183 insertions(+), 40 deletions(-)

diff --git a/Documentation/trace/kprobetrace.txt b/Documentation/trace/kprobetrace.txt index 1d082f8ffeee..8bf752dfc072 100644 --- a/Documentation/trace/kprobetrace.txt +++ b/Documentation/trace/kprobetrace.txt @@ -65,9 +65,22 @@ in decimal ('s' and 'u') or hexadecimal ('x'). Without type casting, 'x32' or 'x64' is used depends on the architecture (e.g. x86-32 uses x32, and x86-64 uses x64). +These value types can be an array. To record array data, you can add '[N]' +(where N is a fixed number, less than 64) to the base type. +E.g. 'x16[4]' means an array of x16 (2bytes hex) with 4 elements. +Note that the array can be applied to memory type fetchargs, you can not +apply it to registers/stack-entries etc. (for example, '$stack1:x8[8]' is +wrong, but '+8($stack):x8[8]' is OK.)

String type is a special type, which fetches a "null-terminated" string from kernel space. This means it will fail and store NULL if the string container has been paged out. +The string array type is a bit different from other types. For other base +types, <base-type>[1] is equal to <base-type> (e.g. +0(%di):x32[1] is same +as +0(%di):x32.) But string[1] is not equal to string. The string type itself +represents "char array", but string array type represents "char * array". +So, for example, +0(%di):string[1] is equal to +0(+0(%di)):string.

Bitfield is another special type, which takes 3 parameters, bit-width, bit- offset, and container-size (usually 32). The syntax is; diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index bcd1fd87082d..b7c6698265e5 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -4614,7 +4614,8 @@ static const char readme_msg[] = "\t $stack<index>, $stack, $retval, $comm\n" #endif "\t type: s8/16/32/64, u8/16/32/64, x8/16/32/64, string, symbol,\n"

• "\t b<bit-width>@<bit-offset>/<container-size>\n"

• "\t b<bit-width>@<bit-offset>/<container-size>,\n"
• "\t <type>[<array-size>]\n"

Ah, this brace('[',']') should be escaped, like "<type>[<array-size>]", or we can not distinguish it from other braces which mean "optional" syntax. I'll update it in the next version.

Thanks,