diff options
| author | Naveen N Rao <naveen@kernel.org> | 2024-10-30 12:38:35 +0530 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2024-10-31 11:00:52 +1100 |
| commit | be87d713eaddf0421ccd61cc060c4c29bc36fc9b (patch) | |
| tree | 7328fca22cf32ab040555d974968a79f6465f7d9 /arch/powerpc | |
| parent | 0b9846529e29ba988ce88b98df633de79675fcb3 (diff) | |
powerpc/kprobes: Use ftrace to determine if a probe is at function entry
Rather than hard-coding the offset into a function to be used to
determine if a kprobe is at function entry, use ftrace_location() to
determine the ftrace location within the function and categorize all
instructions till that offset to be function entry.
For functions that cannot be traced, we fall back to using a fixed
offset of 8 (two instructions) to categorize a probe as being at
function entry for 64-bit elfv2, unless we are using pcrel.
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Naveen N Rao <naveen@kernel.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://patch.msgid.link/20241030070850.1361304-3-hbathini@linux.ibm.com
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/kernel/kprobes.c | 18 |
1 files changed, 8 insertions, 10 deletions
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c index f8aa91bc3b17..bf382c459e1f 100644 --- a/arch/powerpc/kernel/kprobes.c +++ b/arch/powerpc/kernel/kprobes.c @@ -105,24 +105,22 @@ kprobe_opcode_t *kprobe_lookup_name(const char *name, unsigned int offset) return addr; } -static bool arch_kprobe_on_func_entry(unsigned long offset) +static bool arch_kprobe_on_func_entry(unsigned long addr, unsigned long offset) { -#ifdef CONFIG_PPC64_ELF_ABI_V2 -#ifdef CONFIG_KPROBES_ON_FTRACE - return offset <= 16; -#else - return offset <= 8; -#endif -#else + unsigned long ip = ftrace_location(addr); + + if (ip) + return offset <= (ip - addr); + if (IS_ENABLED(CONFIG_PPC64_ELF_ABI_V2) && !IS_ENABLED(CONFIG_PPC_KERNEL_PCREL)) + return offset <= 8; return !offset; -#endif } /* XXX try and fold the magic of kprobe_lookup_name() in this */ kprobe_opcode_t *arch_adjust_kprobe_addr(unsigned long addr, unsigned long offset, bool *on_func_entry) { - *on_func_entry = arch_kprobe_on_func_entry(offset); + *on_func_entry = arch_kprobe_on_func_entry(addr, offset); return (kprobe_opcode_t *)(addr + offset); } |