On Fri Jun 21, 2024 at 4:54 AM AEST, Naveen N Rao 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, unless we are using pcrel. > > Acked-by: Masami Hiramatsu (Google) <[email protected]> > Signed-off-by: Naveen N Rao <[email protected]> > --- > 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 14c5ddec3056..ca204f4f21c1 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;
If it is PCREL, why not offset == 0 as well? Thanks, Nick
