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 1018867022b6..8423815ff986 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 0a809efabeb6..a7e36606718a 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, ¶m); 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, ¶m); 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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