On Fri, Apr 06, 2018 at 10:06:26PM +0300, Alexey Budankov wrote: > On 06.04.2018 18:31, Andi Kleen wrote: > >> diff --git a/arch/x86/kernel/perf_regs.c b/arch/x86/kernel/perf_regs.c > >> index e47b2dbbdef3..9284048cf5b0 100644 > >> --- a/arch/x86/kernel/perf_regs.c > >> +++ b/arch/x86/kernel/perf_regs.c > >> @@ -157,6 +157,15 @@ void perf_get_regs_user(struct perf_regs *regs_user, > >> */ > >> regs_user_copy->bx = -1; > >> regs_user_copy->bp = -1; > >> + if (user_64bit_mode(user_regs)) { > > > > Why is it 64bit only? Should work on 32bit too. > > bp register is a part of i386 syscall ABI > (http://man7.org/linux/man-pages/man2/syscall.2.html) > so not sure if it will make any sense for 32bit processes.
Both 32bit and 64bit use the same frame pointer, if they use frame pointer. -Andi