| Message ID | 15f0b3a2e72326423cfb4ce4e89afff540042245.1702045299.git.naveen@kernel.org (mailing list archive) |
|---|---|
| State | RFC |
| Headers | show |
| Series | powerpc: ftrace updates | expand |
On Fri, 8 Dec 2023 22:00:44 +0530 Naveen N Rao <naveen@kernel.org> wrote: > 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. > OK, so this can cover both KPROBES_ON_FTRACE=y/n cases and the function is traced by ftrace or not. Looks good to me. Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org> Thanks, > Signed-off-by: Naveen N Rao <naveen@kernel.org> > --- > arch/powerpc/kernel/kprobes.c | 18 ++++++++---------- > 1 file changed, 8 insertions(+), 10 deletions(-) > > diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c > index b20ee72e873a..42665dfab59e 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)) > + 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); > } > > -- > 2.43.0 >
diff --git a/arch/powerpc/kernel/kprobes.c b/arch/powerpc/kernel/kprobes.c index b20ee72e873a..42665dfab59e 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)) + 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); }
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. Signed-off-by: Naveen N Rao <naveen@kernel.org> --- arch/powerpc/kernel/kprobes.c | 18 ++++++++---------- 1 file changed, 8 insertions(+), 10 deletions(-)