On Wed, May 08, 2019 at 02:04:16PM +0200, Peter Zijlstra wrote: > On Wed, May 08, 2019 at 06:54:16AM -0500, Josh Poimboeuf wrote: > > On Wed, May 08, 2019 at 09:49:03AM +0200, Peter Zijlstra wrote: > > > The kprobe trampolines have a FRAME_POINTER annotation that makes no > > > sense. It marks the frame in the middle of pt_regs, at the place of > > > saving BP. > > > > > > Change it to mark the pt_regs frame as per the ENCODE_FRAME_POINTER > > > from the respective entry_*.S. > > > > > > Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> > > > --- > > > arch/x86/kernel/kprobes/common.h | 32 +++++++++++++++++++++++--------- > > > 1 file changed, 23 insertions(+), 9 deletions(-) > > > > > > --- a/arch/x86/kernel/kprobes/common.h > > > +++ b/arch/x86/kernel/kprobes/common.h > > > @@ -6,14 +6,15 @@ > > > > > > #include <asm/asm.h> > > > > > > +#ifdef CONFIG_X86_64 > > > + > > > #ifdef CONFIG_FRAME_POINTER > > > -# define SAVE_RBP_STRING " push %" _ASM_BP "\n" \ > > > - " mov %" _ASM_SP ", %" _ASM_BP "\n" > > > +#define ENCODE_FRAME_POINTER \ > > > + " leaq 1(%rsp), %rbp\n" > > > #else > > > -# define SAVE_RBP_STRING " push %" _ASM_BP "\n" > > > +#define ENCODE_FRAME_POINTER > > > #endif > > > > > +#ifdef CONFIG_FRAME_POINTER > > > +#define ENCODE_FRAME_POINTER \ > > > + " movl %esp, %ebp\n" \ > > > + " andl $0x7fffffff, %ebp\n" > > > +#else > > > +#define ENCODE_FRAME_POINTER > > > +#endif > > > > We should put these macros in a header file somewhere (including > > stringified versions). > > Probably a good idea. I'll frob them into asm/frame.h. > > Do the x86_64 variants also want some ORC annotation? Maybe so. Though it looks like regs->ip isn't saved. The saved registers might need to be tweaked. I'll need to look into it. -- Josh
