Add bpf trampoline support for arm64. Most of the logic is the same as x86.
Tested on raspberry pi 4b and qemu with KASLR disabled (avoid long jump), result: #9 /1 bpf_cookie/kprobe:OK #9 /2 bpf_cookie/multi_kprobe_link_api:FAIL #9 /3 bpf_cookie/multi_kprobe_attach_api:FAIL #9 /4 bpf_cookie/uprobe:OK #9 /5 bpf_cookie/tracepoint:OK #9 /6 bpf_cookie/perf_event:OK #9 /7 bpf_cookie/trampoline:OK #9 /8 bpf_cookie/lsm:OK #9 bpf_cookie:FAIL #18 /1 bpf_tcp_ca/dctcp:OK #18 /2 bpf_tcp_ca/cubic:OK #18 /3 bpf_tcp_ca/invalid_license:OK #18 /4 bpf_tcp_ca/dctcp_fallback:OK #18 /5 bpf_tcp_ca/rel_setsockopt:OK #18 bpf_tcp_ca:OK #51 /1 dummy_st_ops/dummy_st_ops_attach:OK #51 /2 dummy_st_ops/dummy_init_ret_value:OK #51 /3 dummy_st_ops/dummy_init_ptr_arg:OK #51 /4 dummy_st_ops/dummy_multiple_args:OK #51 dummy_st_ops:OK #55 fentry_fexit:OK #56 fentry_test:OK #57 /1 fexit_bpf2bpf/target_no_callees:OK #57 /2 fexit_bpf2bpf/target_yes_callees:OK #57 /3 fexit_bpf2bpf/func_replace:OK #57 /4 fexit_bpf2bpf/func_replace_verify:OK #57 /5 fexit_bpf2bpf/func_sockmap_update:OK #57 /6 fexit_bpf2bpf/func_replace_return_code:OK #57 /7 fexit_bpf2bpf/func_map_prog_compatibility:OK #57 /8 fexit_bpf2bpf/func_replace_multi:OK #57 /9 fexit_bpf2bpf/fmod_ret_freplace:OK #57 fexit_bpf2bpf:OK #58 fexit_sleep:OK #59 fexit_stress:OK #60 fexit_test:OK #67 get_func_args_test:OK #68 get_func_ip_test:OK #104 modify_return:OK #237 xdp_bpf2bpf:OK
bpf_cookie/multi_kprobe_link_api and bpf_cookie/multi_kprobe_attach_api failed due to lack of multi_kprobe on arm64.
v4: - Run the test cases on raspberry pi 4b - Rebase and add cookie to trampoline - As Steve suggested, move trace_direct_tramp() back to entry-ftrace.S to avoid messing up generic code with architecture specific code - As Jakub suggested, merge patch 4 and patch 5 of v3 to provide full function in one patch - As Mark suggested, add a comment for the use of aarch64_insn_patch_text_nosync() - Do not generate trampoline for long jump to avoid triggering ftrace_bug - Round stack size to multiples of 16B to avoid SPAlignmentFault - Use callee saved register x20 to reduce the use of mov_i64 - Add missing BTI J instructions - Trivial spelling and code sytle fixes
v3: https://lore.kernel.org/bpf/20220424154028.1698685-1-xukuohai@huawei.com/ - Append test results for bpf_tcp_ca, dummy_st_ops, fexit_bpf2bpf, xdp_bpf2bpf - Support to poke bpf progs - Fix return value of arch_prepare_bpf_trampoline() to the total number of bytes instead of number of instructions - Do not check whether CONFIG_DYNAMIC_FTRACE_WITH_REGS is enabled in arch_prepare_bpf_trampoline, since the trampoline may be hooked to a bpf prog - Restrict bpf_arch_text_poke() to poke bpf text only, as kernel functions are poked by ftrace - Rewrite trace_direct_tramp() in inline assembly in trace_selftest.c to avoid messing entry-ftrace.S - isolate arch_ftrace_set_direct_caller() with macro CONFIG_HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS to avoid compile error when this macro is disabled - Some trivial code sytle fixes
v2: https://lore.kernel.org/bpf/20220414162220.1985095-1-xukuohai@huawei.com/ - Add Song's ACK - Change the multi-line comment in is_valid_bpf_tramp_flags() into net style (patch 3) - Fix a deadloop issue in ftrace selftest (patch 2) - Replace pt_regs->x0 with pt_regs->orig_x0 in patch 1 commit message - Replace "bpf trampoline" with "custom trampoline" in patch 1, as ftrace direct call is not only used by bpf trampoline.
v1: https://lore.kernel.org/bpf/20220413054959.1053668-1-xukuohai@huawei.com/
Xu Kuohai (6): arm64: ftrace: Add ftrace direct call support ftrace: Fix deadloop caused by direct call in ftrace selftest bpf: Move is_valid_bpf_tramp_flags() to the public trampoline code bpf, arm64: Impelment bpf_arch_text_poke() for arm64 bpf, arm64: bpf trampoline for arm64 selftests/bpf: Fix trivial typo in fentry_fexit.c
arch/arm64/Kconfig | 2 + arch/arm64/include/asm/ftrace.h | 22 + arch/arm64/kernel/asm-offsets.c | 1 + arch/arm64/kernel/entry-ftrace.S | 28 +- arch/arm64/net/bpf_jit.h | 1 + arch/arm64/net/bpf_jit_comp.c | 523 +++++++++++++++++- arch/x86/net/bpf_jit_comp.c | 20 - include/linux/bpf.h | 6 + kernel/bpf/bpf_struct_ops.c | 4 +- kernel/bpf/trampoline.c | 34 +- kernel/trace/trace_selftest.c | 2 + .../selftests/bpf/prog_tests/fentry_fexit.c | 4 +- 12 files changed, 603 insertions(+), 44 deletions(-)
Add ftrace direct support for arm64.
1. When there is custom trampoline only, replace the fentry nop to a jump instruction that jumps directly to the custom trampoline.
2. When ftrace trampoline and custom trampoline coexist, jump from fentry to ftrace trampoline first, then jump to custom trampoline when ftrace trampoline exits. The current unused register pt_regs->orig_x0 is used as an intermediary for jumping from ftrace trampoline to custom trampoline.
Signed-off-by: Xu Kuohai xukuohai@huawei.com Acked-by: Song Liu songliubraving@fb.com --- arch/arm64/Kconfig | 2 ++ arch/arm64/include/asm/ftrace.h | 12 ++++++++++++ arch/arm64/kernel/asm-offsets.c | 1 + arch/arm64/kernel/entry-ftrace.S | 18 +++++++++++++++--- 4 files changed, 30 insertions(+), 3 deletions(-)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 57c4c995965f..81cc330daafc 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -177,6 +177,8 @@ config ARM64 select HAVE_DYNAMIC_FTRACE select HAVE_DYNAMIC_FTRACE_WITH_REGS \ if $(cc-option,-fpatchable-function-entry=2) + select HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS \ + if DYNAMIC_FTRACE_WITH_REGS select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY \ if DYNAMIC_FTRACE_WITH_REGS select HAVE_EFFICIENT_UNALIGNED_ACCESS diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h index 1494cfa8639b..14a35a5df0a1 100644 --- a/arch/arm64/include/asm/ftrace.h +++ b/arch/arm64/include/asm/ftrace.h @@ -78,6 +78,18 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr) return addr; }
+#ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS +static inline void arch_ftrace_set_direct_caller(struct pt_regs *regs, + unsigned long addr) +{ + /* + * Place custom trampoline address in regs->orig_x0 to let ftrace + * trampoline jump to it. + */ + regs->orig_x0 = addr; +} +#endif /* CONFIG_HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ + #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS struct dyn_ftrace; int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec); diff --git a/arch/arm64/kernel/asm-offsets.c b/arch/arm64/kernel/asm-offsets.c index 1197e7679882..b1ed0bf01c59 100644 --- a/arch/arm64/kernel/asm-offsets.c +++ b/arch/arm64/kernel/asm-offsets.c @@ -80,6 +80,7 @@ int main(void) DEFINE(S_SDEI_TTBR1, offsetof(struct pt_regs, sdei_ttbr1)); DEFINE(S_PMR_SAVE, offsetof(struct pt_regs, pmr_save)); DEFINE(S_STACKFRAME, offsetof(struct pt_regs, stackframe)); + DEFINE(S_ORIG_X0, offsetof(struct pt_regs, orig_x0)); DEFINE(PT_REGS_SIZE, sizeof(struct pt_regs)); BLANK(); #ifdef CONFIG_COMPAT diff --git a/arch/arm64/kernel/entry-ftrace.S b/arch/arm64/kernel/entry-ftrace.S index e535480a4069..dfe62c55e3a2 100644 --- a/arch/arm64/kernel/entry-ftrace.S +++ b/arch/arm64/kernel/entry-ftrace.S @@ -60,6 +60,9 @@ str x29, [sp, #S_FP] .endif
+ /* Set orig_x0 to zero */ + str xzr, [sp, #S_ORIG_X0] + /* Save the callsite's SP and LR */ add x10, sp, #(PT_REGS_SIZE + 16) stp x9, x10, [sp, #S_LR] @@ -119,12 +122,21 @@ ftrace_common_return: /* Restore the callsite's FP, LR, PC */ ldr x29, [sp, #S_FP] ldr x30, [sp, #S_LR] - ldr x9, [sp, #S_PC] - + ldr x10, [sp, #S_PC] + + ldr x11, [sp, #S_ORIG_X0] + cbz x11, 1f + /* Set x9 to parent ip before jump to custom trampoline */ + mov x9, x30 + /* Set lr to self ip */ + ldr x30, [sp, #S_PC] + /* Set x10 (used for return address) to custom trampoline */ + mov x10, x11 +1: /* Restore the callsite's SP */ add sp, sp, #PT_REGS_SIZE + 16
- ret x9 + ret x10 SYM_CODE_END(ftrace_common)
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
After direct call is enabled for arm64, ftrace selftest enters a dead loop:
<trace_selftest_dynamic_test_func>: 00 bti c 01 mov x9, x30 <trace_direct_tramp>: 02 bl <trace_direct_tramp> ----------> ret | lr/x30 is 03, return to 03 | 03 mov w0, #0x0 <-----------------------------| | | | dead loop! | | | 04 ret ---- lr/x30 is still 03, go back to 03 ----|
The reason is that when the direct caller trace_direct_tramp() returns to the patched function trace_selftest_dynamic_test_func(), lr is still the address after the instrumented instruction in the patched function, so when the patched function exits, it returns to itself!
To fix this issue, we need to restore lr before trace_direct_tramp() exits, so rewrite a dedicated trace_direct_tramp() for arm64.
Reported-by: Li Huafei lihuafei1@huawei.com Signed-off-by: Xu Kuohai xukuohai@huawei.com --- arch/arm64/include/asm/ftrace.h | 10 ++++++++++ arch/arm64/kernel/entry-ftrace.S | 10 ++++++++++ kernel/trace/trace_selftest.c | 2 ++ 3 files changed, 22 insertions(+)
diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h index 14a35a5df0a1..6f6b184e72fb 100644 --- a/arch/arm64/include/asm/ftrace.h +++ b/arch/arm64/include/asm/ftrace.h @@ -126,6 +126,16 @@ static inline bool arch_syscall_match_sym_name(const char *sym, */ return !strcmp(sym + 8, name); } + +#ifdef CONFIG_FTRACE_SELFTEST +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS + +#define trace_direct_tramp trace_direct_tramp +extern void trace_direct_tramp(void); + +#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ +#endif /* CONFIG_FTRACE_SELFTEST */ + #endif /* ifndef __ASSEMBLY__ */
#endif /* __ASM_FTRACE_H */ diff --git a/arch/arm64/kernel/entry-ftrace.S b/arch/arm64/kernel/entry-ftrace.S index dfe62c55e3a2..a47e87d4d3dd 100644 --- a/arch/arm64/kernel/entry-ftrace.S +++ b/arch/arm64/kernel/entry-ftrace.S @@ -357,3 +357,13 @@ SYM_CODE_START(return_to_handler) ret SYM_CODE_END(return_to_handler) #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ + +#ifdef CONFIG_FTRACE_SELFTEST +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS +SYM_FUNC_START(trace_direct_tramp) + mov x10, x30 + mov x30, x9 + ret x10 +SYM_FUNC_END(trace_direct_tramp) +#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ +#endif /* CONFIG_FTRACE_SELFTEST */ diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c index abcadbe933bb..e7ccd0d10c39 100644 --- a/kernel/trace/trace_selftest.c +++ b/kernel/trace/trace_selftest.c @@ -785,8 +785,10 @@ static struct fgraph_ops fgraph_ops __initdata = { };
#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS +#ifndef trace_direct_tramp noinline __noclone static void trace_direct_tramp(void) { } #endif +#endif
/* * Pretty much the same than for the function tracer from which the selftest
On Tue, 17 May 2022 03:18:34 -0400 Xu Kuohai xukuohai@huawei.com wrote:
After direct call is enabled for arm64, ftrace selftest enters a dead loop:
<trace_selftest_dynamic_test_func>: 00 bti c 01 mov x9, x30 <trace_direct_tramp>: 02 bl <trace_direct_tramp> ----------> ret | lr/x30 is 03, return to 03 | 03 mov w0, #0x0 <-----------------------------| | | | dead loop! | | | 04 ret ---- lr/x30 is still 03, go back to 03 ----|
The reason is that when the direct caller trace_direct_tramp() returns to the patched function trace_selftest_dynamic_test_func(), lr is still the address after the instrumented instruction in the patched function, so when the patched function exits, it returns to itself!
To fix this issue, we need to restore lr before trace_direct_tramp() exits, so rewrite a dedicated trace_direct_tramp() for arm64.
Reported-by: Li Huafei lihuafei1@huawei.com Signed-off-by: Xu Kuohai xukuohai@huawei.com
Acked-by: Steven Rostedt (Google) rostedt@goodmis.org
-- Steve
is_valid_bpf_tramp_flags() is not relevant to architecture, so move it to the public trampoline code.
Signed-off-by: Xu Kuohai xukuohai@huawei.com Acked-by: Song Liu songliubraving@fb.com --- arch/x86/net/bpf_jit_comp.c | 20 -------------------- include/linux/bpf.h | 6 ++++++ kernel/bpf/bpf_struct_ops.c | 4 ++-- kernel/bpf/trampoline.c | 34 +++++++++++++++++++++++++++++++--- 4 files changed, 39 insertions(+), 25 deletions(-)
diff --git a/arch/x86/net/bpf_jit_comp.c b/arch/x86/net/bpf_jit_comp.c index a2b6d197c226..7698ef3b4821 100644 --- a/arch/x86/net/bpf_jit_comp.c +++ b/arch/x86/net/bpf_jit_comp.c @@ -1922,23 +1922,6 @@ static int invoke_bpf_mod_ret(const struct btf_func_model *m, u8 **pprog, return 0; }
-static bool is_valid_bpf_tramp_flags(unsigned int flags) -{ - if ((flags & BPF_TRAMP_F_RESTORE_REGS) && - (flags & BPF_TRAMP_F_SKIP_FRAME)) - return false; - - /* - * BPF_TRAMP_F_RET_FENTRY_RET is only used by bpf_struct_ops, - * and it must be used alone. - */ - if ((flags & BPF_TRAMP_F_RET_FENTRY_RET) && - (flags & ~BPF_TRAMP_F_RET_FENTRY_RET)) - return false; - - return true; -} - /* Example: * __be16 eth_type_trans(struct sk_buff *skb, struct net_device *dev); * its 'struct btf_func_model' will be nr_args=2 @@ -2017,9 +2000,6 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, void *i if (nr_args > 6) return -ENOTSUPP;
- if (!is_valid_bpf_tramp_flags(flags)) - return -EINVAL; - /* Generated trampoline stack layout: * * RBP + 8 [ return address ] diff --git a/include/linux/bpf.h b/include/linux/bpf.h index c107392b0ba7..5615f31b2a30 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -760,6 +760,12 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *tr, void *image, void *i const struct btf_func_model *m, u32 flags, struct bpf_tramp_links *tlinks, void *orig_call); +int bpf_prepare_trampoline(struct bpf_tramp_image *tr, void *image, void *image_end, + const struct btf_func_model *m, u32 flags, + struct bpf_tramp_links *tlinks, + void *orig_call); + + /* these two functions are called from generated trampoline */ u64 notrace __bpf_prog_enter(struct bpf_prog *prog, struct bpf_tramp_run_ctx *run_ctx); void notrace __bpf_prog_exit(struct bpf_prog *prog, u64 start, struct bpf_tramp_run_ctx *run_ctx); diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c index d9a3c9207240..4d81675e0dd5 100644 --- a/kernel/bpf/bpf_struct_ops.c +++ b/kernel/bpf/bpf_struct_ops.c @@ -342,8 +342,8 @@ int bpf_struct_ops_prepare_trampoline(struct bpf_tramp_links *tlinks, tlinks[BPF_TRAMP_FENTRY].links[0] = link; tlinks[BPF_TRAMP_FENTRY].nr_links = 1; flags = model->ret_size > 0 ? BPF_TRAMP_F_RET_FENTRY_RET : 0; - return arch_prepare_bpf_trampoline(NULL, image, image_end, - model, flags, tlinks, NULL); + return bpf_prepare_trampoline(NULL, image, image_end, model, flags, + tlinks, NULL); }
static int bpf_struct_ops_map_update_elem(struct bpf_map *map, void *key, diff --git a/kernel/bpf/trampoline.c b/kernel/bpf/trampoline.c index 93c7675f0c9e..bef786fe307d 100644 --- a/kernel/bpf/trampoline.c +++ b/kernel/bpf/trampoline.c @@ -363,9 +363,9 @@ static int bpf_trampoline_update(struct bpf_trampoline *tr) if (ip_arg) flags |= BPF_TRAMP_F_IP_ARG;
- err = arch_prepare_bpf_trampoline(im, im->image, im->image + PAGE_SIZE, - &tr->func.model, flags, tlinks, - tr->func.addr); + err = bpf_prepare_trampoline(im, im->image, im->image + PAGE_SIZE, + &tr->func.model, flags, tlinks, + tr->func.addr); if (err < 0) goto out;
@@ -671,6 +671,34 @@ arch_prepare_bpf_trampoline(struct bpf_tramp_image *tr, void *image, void *image return -ENOTSUPP; }
+static bool is_valid_bpf_tramp_flags(unsigned int flags) +{ + if ((flags & BPF_TRAMP_F_RESTORE_REGS) && + (flags & BPF_TRAMP_F_SKIP_FRAME)) + return false; + + /* BPF_TRAMP_F_RET_FENTRY_RET is only used by bpf_struct_ops, + * and it must be used alone. + */ + if ((flags & BPF_TRAMP_F_RET_FENTRY_RET) && + (flags & ~BPF_TRAMP_F_RET_FENTRY_RET)) + return false; + + return true; +} + +int bpf_prepare_trampoline(struct bpf_tramp_image *tr, void *image, + void *image_end, const struct btf_func_model *m, + u32 flags, struct bpf_tramp_links *tlinks, + void *orig_call) +{ + if (!is_valid_bpf_tramp_flags(flags)) + return -EINVAL; + + return arch_prepare_bpf_trampoline(tr, image, image_end, m, flags, + tlinks, orig_call); +} + static int __init init_trampolines(void) { int i;
On Tue, May 17, 2022 at 03:18:35AM -0400, Xu Kuohai wrote:
+static bool is_valid_bpf_tramp_flags(unsigned int flags) +{
- if ((flags & BPF_TRAMP_F_RESTORE_REGS) &&
(flags & BPF_TRAMP_F_SKIP_FRAME))return false;- /* BPF_TRAMP_F_RET_FENTRY_RET is only used by bpf_struct_ops,
* and it must be used alone.*/- if ((flags & BPF_TRAMP_F_RET_FENTRY_RET) &&
(flags & ~BPF_TRAMP_F_RET_FENTRY_RET))return false;- return true;
+}
+int bpf_prepare_trampoline(struct bpf_tramp_image *tr, void *image,
void *image_end, const struct btf_func_model *m,u32 flags, struct bpf_tramp_links *tlinks,void *orig_call)+{
- if (!is_valid_bpf_tramp_flags(flags))
return -EINVAL;- return arch_prepare_bpf_trampoline(tr, image, image_end, m, flags,
tlinks, orig_call);+}
It's an overkill to introduce a new helper function just to validate flags that almost compile time constants. The flags are not user supplied. Please move /* BPF_TRAMP_F_RET_FENTRY_RET is only used by bpf_struct_ops ... */ comment to bpf_struct_ops.c right before it calls arch_prepare_bpf_trampoline() And add a comment to trampoline.c saying that BPF_TRAMP_F_RESTORE_REGS and BPF_TRAMP_F_SKIP_FRAME should not be set together. We could add a warn_on there or in arch code, but feels like overkill.
On 5/17/2022 11:53 PM, Alexei Starovoitov wrote:
On Tue, May 17, 2022 at 03:18:35AM -0400, Xu Kuohai wrote:
+static bool is_valid_bpf_tramp_flags(unsigned int flags) +{
- if ((flags & BPF_TRAMP_F_RESTORE_REGS) &&
(flags & BPF_TRAMP_F_SKIP_FRAME))return false;- /* BPF_TRAMP_F_RET_FENTRY_RET is only used by bpf_struct_ops,
* and it must be used alone.*/- if ((flags & BPF_TRAMP_F_RET_FENTRY_RET) &&
(flags & ~BPF_TRAMP_F_RET_FENTRY_RET))return false;- return true;
+}
+int bpf_prepare_trampoline(struct bpf_tramp_image *tr, void *image,
void *image_end, const struct btf_func_model *m,u32 flags, struct bpf_tramp_links *tlinks,void *orig_call)+{
- if (!is_valid_bpf_tramp_flags(flags))
return -EINVAL;- return arch_prepare_bpf_trampoline(tr, image, image_end, m, flags,
tlinks, orig_call);+}
It's an overkill to introduce a new helper function just to validate flags that almost compile time constants. The flags are not user supplied. Please move /* BPF_TRAMP_F_RET_FENTRY_RET is only used by bpf_struct_ops ... */ comment to bpf_struct_ops.c right before it calls arch_prepare_bpf_trampoline() And add a comment to trampoline.c saying that BPF_TRAMP_F_RESTORE_REGS and BPF_TRAMP_F_SKIP_FRAME should not be set together. We could add a warn_on there or in arch code, but feels like overkill. .
OK, will fix in next version.
Impelment bpf_arch_text_poke() for arm64, so bpf trampoline code can use it to replace nop with jump, or replace jump with nop.
Signed-off-by: Xu Kuohai xukuohai@huawei.com Acked-by: Song Liu songliubraving@fb.com Reviewed-by: Jakub Sitnicki jakub@cloudflare.com --- arch/arm64/net/bpf_jit.h | 1 + arch/arm64/net/bpf_jit_comp.c | 107 +++++++++++++++++++++++++++++++--- 2 files changed, 99 insertions(+), 9 deletions(-)
diff --git a/arch/arm64/net/bpf_jit.h b/arch/arm64/net/bpf_jit.h index 194c95ccc1cf..1c4b0075a3e2 100644 --- a/arch/arm64/net/bpf_jit.h +++ b/arch/arm64/net/bpf_jit.h @@ -270,6 +270,7 @@ #define A64_BTI_C A64_HINT(AARCH64_INSN_HINT_BTIC) #define A64_BTI_J A64_HINT(AARCH64_INSN_HINT_BTIJ) #define A64_BTI_JC A64_HINT(AARCH64_INSN_HINT_BTIJC) +#define A64_NOP A64_HINT(AARCH64_INSN_HINT_NOP)
/* DMB */ #define A64_DMB_ISH aarch64_insn_gen_dmb(AARCH64_INSN_MB_ISH) diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c index 8ab4035dea27..5ce6ed5f42a1 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -9,6 +9,7 @@
#include <linux/bitfield.h> #include <linux/bpf.h> +#include <linux/memory.h> #include <linux/filter.h> #include <linux/printk.h> #include <linux/slab.h> @@ -18,6 +19,7 @@ #include <asm/cacheflush.h> #include <asm/debug-monitors.h> #include <asm/insn.h> +#include <asm/patching.h> #include <asm/set_memory.h>
#include "bpf_jit.h" @@ -235,13 +237,13 @@ static bool is_lsi_offset(int offset, int scale) return true; }
+#define BTI_INSNS (IS_ENABLED(CONFIG_ARM64_BTI_KERNEL) ? 1 : 0) +#define PAC_INSNS (IS_ENABLED(CONFIG_ARM64_PTR_AUTH_KERNEL) ? 1 : 0) + /* Tail call offset to jump into */ -#if IS_ENABLED(CONFIG_ARM64_BTI_KERNEL) || \ - IS_ENABLED(CONFIG_ARM64_PTR_AUTH_KERNEL) -#define PROLOGUE_OFFSET 9 -#else -#define PROLOGUE_OFFSET 8 -#endif +#define PROLOGUE_OFFSET (BTI_INSNS + 2 + PAC_INSNS + 8) +/* Offset of nop instruction in bpf prog entry to be poked */ +#define POKE_OFFSET (BTI_INSNS + 1)
static int build_prologue(struct jit_ctx *ctx, bool ebpf_from_cbpf) { @@ -279,12 +281,15 @@ static int build_prologue(struct jit_ctx *ctx, bool ebpf_from_cbpf) * */
+ if (IS_ENABLED(CONFIG_ARM64_BTI_KERNEL)) + emit(A64_BTI_C, ctx); + + emit(A64_MOV(1, A64_R(9), A64_LR), ctx); + emit(A64_NOP, ctx); + /* Sign lr */ if (IS_ENABLED(CONFIG_ARM64_PTR_AUTH_KERNEL)) emit(A64_PACIASP, ctx); - /* BTI landing pad */ - else if (IS_ENABLED(CONFIG_ARM64_BTI_KERNEL)) - emit(A64_BTI_C, ctx);
/* Save FP and LR registers to stay align with ARM64 AAPCS */ emit(A64_PUSH(A64_FP, A64_LR, A64_SP), ctx); @@ -1529,3 +1534,87 @@ void bpf_jit_free_exec(void *addr) { return vfree(addr); } + +static int gen_branch_or_nop(enum aarch64_insn_branch_type type, void *ip, + void *addr, u32 *insn) +{ + if (!addr) + *insn = aarch64_insn_gen_nop(); + else + *insn = aarch64_insn_gen_branch_imm((unsigned long)ip, + (unsigned long)addr, + type); + + return *insn != AARCH64_BREAK_FAULT ? 0 : -EFAULT; +} + +int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type poke_type, + void *old_addr, void *new_addr) +{ + int ret; + u32 old_insn; + u32 new_insn; + u32 replaced; + unsigned long offset = ~0UL; + enum aarch64_insn_branch_type branch_type; + char namebuf[KSYM_NAME_LEN]; + + if (!__bpf_address_lookup((unsigned long)ip, NULL, &offset, namebuf)) + /* Only poking bpf text is supported. Since kernel function + * entry is set up by ftrace, we reply on ftrace to poke kernel + * functions. + */ + return -EINVAL; + + /* bpf entry */ + if (offset == 0UL) + /* skip to the nop instruction in bpf prog entry: + * bti c // if BTI enabled + * mov x9, x30 + * nop + */ + ip = ip + POKE_OFFSET * AARCH64_INSN_SIZE; + + if (poke_type == BPF_MOD_CALL) + branch_type = AARCH64_INSN_BRANCH_LINK; + else + branch_type = AARCH64_INSN_BRANCH_NOLINK; + + if (gen_branch_or_nop(branch_type, ip, old_addr, &old_insn) < 0) + return -EFAULT; + + if (gen_branch_or_nop(branch_type, ip, new_addr, &new_insn) < 0) + return -EFAULT; + + mutex_lock(&text_mutex); + if (aarch64_insn_read(ip, &replaced)) { + ret = -EFAULT; + goto out; + } + + if (replaced != old_insn) { + ret = -EFAULT; + goto out; + } + + /* We call aarch64_insn_patch_text_nosync() to replace instruction + * atomically, so no other CPUs will fetch a half-new and half-old + * instruction. But there is chance that another CPU fetches the old + * instruction after bpf_arch_text_poke() finishes, that is, different + * CPUs may execute different versions of instructions at the same + * time before the icache is synchronized by hardware. + * + * 1. when a new trampoline is attached, it is not an issue for + * different CPUs to jump to different trampolines temporarily. + * + * 2. when an old trampoline is freed, we should wait for all other + * CPUs to exit the trampoline and make sure the trampoline is no + * longer reachable, since bpf_tramp_image_put() function already + * uses percpu_ref and rcu task to do the sync, no need to call the + * sync interface here. + */ + ret = aarch64_insn_patch_text_nosync(ip, new_insn); +out: + mutex_unlock(&text_mutex); + return ret; +}
Add bpf trampoline support for arm64. Most of the logic is the same as x86.
Tested on raspberry pi 4b and qemu with KASLR disabled (avoid long jump), result: #9 /1 bpf_cookie/kprobe:OK #9 /2 bpf_cookie/multi_kprobe_link_api:FAIL #9 /3 bpf_cookie/multi_kprobe_attach_api:FAIL #9 /4 bpf_cookie/uprobe:OK #9 /5 bpf_cookie/tracepoint:OK #9 /6 bpf_cookie/perf_event:OK #9 /7 bpf_cookie/trampoline:OK #9 /8 bpf_cookie/lsm:OK #9 bpf_cookie:FAIL #18 /1 bpf_tcp_ca/dctcp:OK #18 /2 bpf_tcp_ca/cubic:OK #18 /3 bpf_tcp_ca/invalid_license:OK #18 /4 bpf_tcp_ca/dctcp_fallback:OK #18 /5 bpf_tcp_ca/rel_setsockopt:OK #18 bpf_tcp_ca:OK #51 /1 dummy_st_ops/dummy_st_ops_attach:OK #51 /2 dummy_st_ops/dummy_init_ret_value:OK #51 /3 dummy_st_ops/dummy_init_ptr_arg:OK #51 /4 dummy_st_ops/dummy_multiple_args:OK #51 dummy_st_ops:OK #55 fentry_fexit:OK #56 fentry_test:OK #57 /1 fexit_bpf2bpf/target_no_callees:OK #57 /2 fexit_bpf2bpf/target_yes_callees:OK #57 /3 fexit_bpf2bpf/func_replace:OK #57 /4 fexit_bpf2bpf/func_replace_verify:OK #57 /5 fexit_bpf2bpf/func_sockmap_update:OK #57 /6 fexit_bpf2bpf/func_replace_return_code:OK #57 /7 fexit_bpf2bpf/func_map_prog_compatibility:OK #57 /8 fexit_bpf2bpf/func_replace_multi:OK #57 /9 fexit_bpf2bpf/fmod_ret_freplace:OK #57 fexit_bpf2bpf:OK #58 fexit_sleep:OK #59 fexit_stress:OK #60 fexit_test:OK #67 get_func_args_test:OK #68 get_func_ip_test:OK #104 modify_return:OK #237 xdp_bpf2bpf:OK
bpf_cookie/multi_kprobe_link_api and bpf_cookie/multi_kprobe_attach_api failed due to lack of multi_kprobe on arm64.
Signed-off-by: Xu Kuohai xukuohai@huawei.com Acked-by: Song Liu songliubraving@fb.com --- arch/arm64/net/bpf_jit_comp.c | 420 +++++++++++++++++++++++++++++++++- 1 file changed, 413 insertions(+), 7 deletions(-)
diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c index 5ce6ed5f42a1..59cb96dc4335 100644 --- a/arch/arm64/net/bpf_jit_comp.c +++ b/arch/arm64/net/bpf_jit_comp.c @@ -142,6 +142,12 @@ static inline void emit_a64_mov_i64(const int reg, const u64 val, } }
+static inline void emit_bti(u32 insn, struct jit_ctx *ctx) +{ + if (IS_ENABLED(CONFIG_ARM64_BTI_KERNEL)) + emit(insn, ctx); +} + /* * Kernel addresses in the vmalloc space use at most 48 bits, and the * remaining bits are guaranteed to be 0x1. So we can compose the address @@ -161,6 +167,14 @@ static inline void emit_addr_mov_i64(const int reg, const u64 val, } }
+static inline void emit_call(u64 target, struct jit_ctx *ctx) +{ + u8 tmp = bpf2a64[TMP_REG_1]; + + emit_addr_mov_i64(tmp, target, ctx); + emit(A64_BLR(tmp), ctx); +} + static inline int bpf2a64_offset(int bpf_insn, int off, const struct jit_ctx *ctx) { @@ -281,8 +295,7 @@ static int build_prologue(struct jit_ctx *ctx, bool ebpf_from_cbpf) * */
- if (IS_ENABLED(CONFIG_ARM64_BTI_KERNEL)) - emit(A64_BTI_C, ctx); + emit_bti(A64_BTI_C, ctx);
emit(A64_MOV(1, A64_R(9), A64_LR), ctx); emit(A64_NOP, ctx); @@ -316,8 +329,7 @@ static int build_prologue(struct jit_ctx *ctx, bool ebpf_from_cbpf) }
/* BTI landing pad for the tail call, done with a BR */ - if (IS_ENABLED(CONFIG_ARM64_BTI_KERNEL)) - emit(A64_BTI_J, ctx); + emit_bti(A64_BTI_J, ctx); }
emit(A64_SUB_I(1, fpb, fp, ctx->fpb_offset), ctx); @@ -995,8 +1007,7 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx, &func_addr, &func_addr_fixed); if (ret < 0) return ret; - emit_addr_mov_i64(tmp, func_addr, ctx); - emit(A64_BLR(tmp), ctx); + emit_call(func_addr, ctx); emit(A64_MOV(1, r0, A64_R(0)), ctx); break; } @@ -1340,6 +1351,13 @@ static int validate_code(struct jit_ctx *ctx) if (a64_insn == AARCH64_BREAK_FAULT) return -1; } + return 0; +} + +static int validate_ctx(struct jit_ctx *ctx) +{ + if (validate_code(ctx)) + return -1;
if (WARN_ON_ONCE(ctx->exentry_idx != ctx->prog->aux->num_exentries)) return -1; @@ -1464,7 +1482,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog) build_epilogue(&ctx);
/* 3. Extra pass to validate JITed code. */ - if (validate_code(&ctx)) { + if (validate_ctx(&ctx)) { bpf_jit_binary_free(header); prog = orig_prog; goto out_off; @@ -1535,6 +1553,394 @@ void bpf_jit_free_exec(void *addr) return vfree(addr); }
+static void invoke_bpf_prog(struct jit_ctx *ctx, struct bpf_tramp_link *l, + int args_off, int retval_off, int run_ctx_off, + bool save_ret) +{ + u32 *branch; + u64 enter_prog; + u64 exit_prog; + u8 tmp = bpf2a64[TMP_REG_1]; + u8 r0 = bpf2a64[BPF_REG_0]; + struct bpf_prog *p = l->link.prog; + int cookie_off = offsetof(struct bpf_tramp_run_ctx, bpf_cookie); + + if (p->aux->sleepable) { + enter_prog = (u64)__bpf_prog_enter_sleepable; + exit_prog = (u64)__bpf_prog_exit_sleepable; + } else { + enter_prog = (u64)__bpf_prog_enter; + exit_prog = (u64)__bpf_prog_exit; + } + + if (l->cookie == 0) { + /* if cookie is zero, one instruction is enough to store it */ + emit(A64_STR64I(A64_ZR, A64_SP, run_ctx_off + cookie_off), ctx); + } else { + emit_a64_mov_i64(tmp, l->cookie, ctx); + emit(A64_STR64I(tmp, A64_SP, run_ctx_off + cookie_off), ctx); + } + + /* save p to callee saved register x19 to avoid loading p with mov_i64 + * each time. + */ + emit_addr_mov_i64(A64_R(19), (const u64)p, ctx); + + /* arg1: prog */ + emit(A64_MOV(1, A64_R(0), A64_R(19)), ctx); + /* arg2: &run_ctx */ + emit(A64_ADD_I(1, A64_R(1), A64_SP, run_ctx_off), ctx); + + emit_call(enter_prog, ctx); + + /* if (__bpf_prog_enter(prog) == 0) + * goto skip_exec_of_prog; + */ + branch = ctx->image + ctx->idx; + emit(A64_NOP, ctx); + + /* save return value to callee saved register x20 */ + emit(A64_MOV(1, A64_R(20), r0), ctx); + + emit(A64_ADD_I(1, A64_R(0), A64_SP, args_off), ctx); + if (!p->jited) + emit_addr_mov_i64(A64_R(1), (const u64)p->insnsi, ctx); + + emit_call((const u64)p->bpf_func, ctx); + + /* store return value */ + if (save_ret) + emit(A64_STR64I(r0, A64_SP, retval_off), ctx); + + if (ctx->image) { + int offset = &ctx->image[ctx->idx] - branch; + *branch = A64_CBZ(1, A64_R(0), offset); + } + emit_bti(A64_BTI_J, ctx); + + /* arg1: prog */ + emit(A64_MOV(1, A64_R(0), A64_R(19)), ctx); + /* arg2: start time */ + emit(A64_MOV(1, A64_R(1), A64_R(20)), ctx); + /* arg3: &run_ctx */ + emit(A64_ADD_I(1, A64_R(2), A64_SP, run_ctx_off), ctx); + + emit_call(exit_prog, ctx); +} + +static void invoke_bpf_mod_ret(struct jit_ctx *ctx, struct bpf_tramp_links *tl, + int args_off, int retval_off, int run_ctx_off, + u32 **branches) +{ + int i; + + /* The first fmod_ret program will receive a garbage return value. + * Set this to 0 to avoid confusing the program. + */ + emit(A64_STR64I(A64_ZR, A64_SP, retval_off), ctx); + for (i = 0; i < tl->nr_links; i++) { + invoke_bpf_prog(ctx, tl->links[i], args_off, retval_off, + run_ctx_off, true); + /* if (*(u64 *)(sp + retval_off) != 0) + * goto do_fexit; + */ + emit(A64_LDR64I(A64_R(10), A64_SP, retval_off), ctx); + /* Save the location of branch, and generate a nop. + * This nop will be replaced with a cbnz later. + */ + branches[i] = ctx->image + ctx->idx; + emit(A64_NOP, ctx); + } +} + +static void save_args(struct jit_ctx *ctx, int args_off, int nargs) +{ + int i; + + for (i = 0; i < nargs; i++) { + emit(A64_STR64I(i, A64_SP, args_off), ctx); + args_off += 8; + } +} + +static void restore_args(struct jit_ctx *ctx, int args_off, int nargs) +{ + int i; + + for (i = 0; i < nargs; i++) { + emit(A64_LDR64I(i, A64_SP, args_off), ctx); + args_off += 8; + } +} + +/* Based on the x86's implementation of arch_prepare_bpf_trampoline(). + * + * bpf prog and function entry before bpf trampoline hooked: + * mov x9, x30 + * nop + * + * bpf prog and function entry after bpf trampoline hooked: + * mov x9, x30 + * bl <bpf_trampoline> + * + */ +static int prepare_trampoline(struct jit_ctx *ctx, struct bpf_tramp_image *im, + struct bpf_tramp_links *tlinks, void *orig_call, + int nargs, u32 flags) +{ + int i; + int stack_size; + int retaddr_off; + int regs_off; + int retval_off; + int args_off; + int nargs_off; + int ip_off; + int run_ctx_off; + struct bpf_tramp_links *fentry = &tlinks[BPF_TRAMP_FENTRY]; + struct bpf_tramp_links *fexit = &tlinks[BPF_TRAMP_FEXIT]; + struct bpf_tramp_links *fmod_ret = &tlinks[BPF_TRAMP_MODIFY_RETURN]; + bool save_ret; + u32 **branches = NULL; + + /* trampoline stack layout: + * [ parent ip ] + * [ FP ] + * SP + retaddr_off [ self ip ] + * [ FP ] + * + * [ padding ] align SP to multiples of 16 + * + * [ x20 ] callee saved reg x20 + * sp + regs_off [ x19 ] callee saved reg x19 + * + * SP + retval_off [ return value ] BPF_TRAMP_F_CALL_ORIG or + * BPF_TRAMP_F_RET_FENTRY_RET + * + * [ argN ] + * [ ... ] + * sp + args_off [ arg1 ] + * + * SP + nargs_off [ args count ] + * + * SP + ip_off [ traced function ] BPF_TRAMP_F_IP_ARG flag + * + * SP + run_ctx_off [ bpf_tramp_run_ctx ] + */ + + stack_size = 0; + run_ctx_off = stack_size; + /* room for bpf_tramp_run_ctx */ + stack_size += round_up(sizeof(struct bpf_tramp_run_ctx), 8); + + ip_off = stack_size; + /* room for IP address argument */ + if (flags & BPF_TRAMP_F_IP_ARG) + stack_size += 8; + + nargs_off = stack_size; + /* room for args count */ + stack_size += 8; + + args_off = stack_size; + /* room for args */ + stack_size += nargs * 8; + + /* room for return value */ + retval_off = stack_size; + save_ret = flags & (BPF_TRAMP_F_CALL_ORIG | BPF_TRAMP_F_RET_FENTRY_RET); + if (save_ret) + stack_size += 8; + + /* room for callee saved registers, currently x19 and x20 are used */ + regs_off = stack_size; + stack_size += 16; + + /* round up to multiples of 16 to avoid SPAlignmentFault */ + stack_size = round_up(stack_size, 16); + + /* return address locates above FP */ + retaddr_off = stack_size + 8; + + emit_bti(A64_BTI_C, ctx); + + /* frame for parent function */ + emit(A64_PUSH(A64_FP, A64_R(9), A64_SP), ctx); + emit(A64_MOV(1, A64_FP, A64_SP), ctx); + + /* frame for patched function */ + emit(A64_PUSH(A64_FP, A64_LR, A64_SP), ctx); + emit(A64_MOV(1, A64_FP, A64_SP), ctx); + + /* allocate stack space */ + emit(A64_SUB_I(1, A64_SP, A64_SP, stack_size), ctx); + + if (flags & BPF_TRAMP_F_IP_ARG) { + /* save ip address of the traced function */ + emit_addr_mov_i64(A64_R(10), (const u64)orig_call, ctx); + emit(A64_STR64I(A64_R(10), A64_SP, ip_off), ctx); + } + + /* save args count*/ + emit(A64_MOVZ(1, A64_R(10), nargs, 0), ctx); + emit(A64_STR64I(A64_R(10), A64_SP, nargs_off), ctx); + + /* save args */ + save_args(ctx, args_off, nargs); + + /* save callee saved registers */ + emit(A64_STR64I(A64_R(19), A64_SP, regs_off), ctx); + emit(A64_STR64I(A64_R(20), A64_SP, regs_off + 8), ctx); + + if (flags & BPF_TRAMP_F_CALL_ORIG) { + emit_addr_mov_i64(A64_R(0), (const u64)im, ctx); + emit_call((const u64)__bpf_tramp_enter, ctx); + } + + for (i = 0; i < fentry->nr_links; i++) + invoke_bpf_prog(ctx, fentry->links[i], args_off, + retval_off, run_ctx_off, + flags & BPF_TRAMP_F_RET_FENTRY_RET); + + if (fmod_ret->nr_links) { + branches = kcalloc(fmod_ret->nr_links, sizeof(u32 *), + GFP_KERNEL); + if (!branches) + return -ENOMEM; + + invoke_bpf_mod_ret(ctx, fmod_ret, args_off, retval_off, + run_ctx_off, branches); + } + + if (flags & BPF_TRAMP_F_CALL_ORIG) { + restore_args(ctx, args_off, nargs); + /* call original func */ + emit(A64_LDR64I(A64_R(10), A64_SP, retaddr_off), ctx); + emit(A64_BLR(A64_R(10)), ctx); + /* store return value */ + emit(A64_STR64I(A64_R(0), A64_SP, retval_off), ctx); + /* reserve a nop for bpf_tramp_image_put */ + im->ip_after_call = ctx->image + ctx->idx; + emit(A64_NOP, ctx); + } + + /* update the branches saved in invoke_bpf_mod_ret with cbnz */ + for (i = 0; i < fmod_ret->nr_links && ctx->image != NULL; i++) { + int offset = &ctx->image[ctx->idx] - branches[i]; + *branches[i] = A64_CBNZ(1, A64_R(10), offset); + } + + if (fmod_ret->nr_links) + emit_bti(A64_BTI_J, ctx); + + for (i = 0; i < fexit->nr_links; i++) + invoke_bpf_prog(ctx, fexit->links[i], args_off, retval_off, + run_ctx_off, false); + + if (flags & BPF_TRAMP_F_RESTORE_REGS) + restore_args(ctx, args_off, nargs); + + if (flags & BPF_TRAMP_F_CALL_ORIG) { + im->ip_epilogue = ctx->image + ctx->idx; + emit_bti(A64_BTI_J, ctx); + emit_addr_mov_i64(A64_R(0), (const u64)im, ctx); + emit_call((const u64)__bpf_tramp_exit, ctx); + } + + /* restore callee saved register x19 and x20 */ + emit(A64_LDR64I(A64_R(19), A64_SP, regs_off), ctx); + emit(A64_LDR64I(A64_R(20), A64_SP, regs_off + 8), ctx); + + if (save_ret) + emit(A64_LDR64I(A64_R(0), A64_SP, retval_off), ctx); + + /* reset SP */ + emit(A64_MOV(1, A64_SP, A64_FP), ctx); + + /* pop frames */ + emit(A64_POP(A64_FP, A64_LR, A64_SP), ctx); + emit(A64_POP(A64_FP, A64_R(9), A64_SP), ctx); + + if (flags & BPF_TRAMP_F_SKIP_FRAME) { + /* skip patched function, return to parent */ + emit(A64_MOV(1, A64_LR, A64_R(9)), ctx); + emit(A64_RET(A64_R(9)), ctx); + } else { + /* return to patched function */ + emit(A64_MOV(1, A64_R(10), A64_LR), ctx); + emit(A64_MOV(1, A64_LR, A64_R(9)), ctx); + emit(A64_RET(A64_R(10)), ctx); + } + + if (ctx->image) + bpf_flush_icache(ctx->image, ctx->image + ctx->idx); + + kfree(branches); + + return ctx->idx; +} + +static inline bool is_long_jump(void *ip, void *target) +{ + long offset; + + /* when ip == NULL, the trampoline address is used by bpf_struct_ops + * as a normal kernel function pointer, which can be always jumped to, + * so don't treat it as a long jump. + */ + if (ip == NULL) + return false; + + offset = (long)target - (long)ip; + return offset < -SZ_128M || offset >= SZ_128M; +} + +int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image, + void *image_end, const struct btf_func_model *m, + u32 flags, struct bpf_tramp_links *tlinks, + void *orig_call) +{ + int ret; + int nargs = m->nr_args; + int max_insns = ((long)image_end - (long)image) / AARCH64_INSN_SIZE; + struct jit_ctx ctx = { + .image = NULL, + .idx = 0 + }; + + /* Return error since the long jump is not implemented. Otherwise, + * ftrace_bug will be triggered when the fentry is patched by ftrace, + * making ftrace no longer work properly. + */ + if (is_long_jump(orig_call, image)) + return -ENOTSUPP; + + /* the first 8 arguments are passed by registers */ + if (nargs > 8) + return -ENOTSUPP; + + ret = prepare_trampoline(&ctx, im, tlinks, orig_call, nargs, flags); + if (ret < 0) + return ret; + + if (ret > max_insns) + return -EFBIG; + + ctx.image = image; + ctx.idx = 0; + + jit_fill_hole(image, (unsigned int)(image_end - image)); + ret = prepare_trampoline(&ctx, im, tlinks, orig_call, nargs, flags); + + if (ret > 0 && validate_code(&ctx) < 0) + ret = -EINVAL; + + if (ret > 0) + ret *= AARCH64_INSN_SIZE; + + return ret; +} + static int gen_branch_or_nop(enum aarch64_insn_branch_type type, void *ip, void *addr, u32 *insn) {
The "ipv6" word in assertion message should be "fentry_fexit".
Signed-off-by: Xu Kuohai xukuohai@huawei.com Acked-by: Song Liu songliubraving@fb.com --- tools/testing/selftests/bpf/prog_tests/fentry_fexit.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/fentry_fexit.c b/tools/testing/selftests/bpf/prog_tests/fentry_fexit.c index 130f5b82d2e6..e3c139bde46e 100644 --- a/tools/testing/selftests/bpf/prog_tests/fentry_fexit.c +++ b/tools/testing/selftests/bpf/prog_tests/fentry_fexit.c @@ -28,8 +28,8 @@ void test_fentry_fexit(void)
prog_fd = fexit_skel->progs.test1.prog_fd; err = bpf_prog_test_run_opts(prog_fd, &topts); - ASSERT_OK(err, "ipv6 test_run"); - ASSERT_OK(topts.retval, "ipv6 test retval"); + ASSERT_OK(err, "fentry_fexit test_run"); + ASSERT_OK(topts.retval, "fentry_fexit test retval");
fentry_res = (__u64 *)fentry_skel->bss; fexit_res = (__u64 *)fexit_skel->bss;
linux-kselftest-mirror@lists.linaro.org
-
Alexei Starovoitov -
Steven Rostedt -
Xu Kuohai