From: Florent Revest revest@chromium.org

The ftrace-direct-too sample traces the handle_mm_fault function whose signature changed since the introduction of the sample. Since: commit bce617edecad ("mm: do page fault accounting in handle_mm_fault") handle_mm_fault now has 4 arguments. Therefore, the sample trampoline should save 4 argument registers.

s390 saves all argument registers already so it does not need a change but x86_64 needs an extra push and pop.

This also evolves the signature of the tracing function to make it mirror the signature of the traced function.

Link: https://lkml.kernel.org/r/20230427140700.625241-2-revest@chromium.org

Cc: stable@vger.kernel.org Fixes: bce617edecad ("mm: do page fault accounting in handle_mm_fault") Reviewed-by: Steven Rostedt (Google) rostedt@goodmis.org Reviewed-by: Mark Rutland mark.rutland@arm.com Acked-by: Catalin Marinas catalin.marinas@arm.com Signed-off-by: Florent Revest revest@chromium.org Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org --- samples/ftrace/ftrace-direct-too.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/samples/ftrace/ftrace-direct-too.c b/samples/ftrace/ftrace-direct-too.c index a05bc2cc2261..7986033887f6 100644 --- a/samples/ftrace/ftrace-direct-too.c +++ b/samples/ftrace/ftrace-direct-too.c @@ -5,14 +5,14 @@ #include <linux/ftrace.h> #include <asm/asm-offsets.h>

-extern void my_direct_func(struct vm_area_struct *vma, - unsigned long address, unsigned int flags); +extern void my_direct_func(struct vm_area_struct *vma, unsigned long address, + unsigned int flags, struct pt_regs *regs);

-void my_direct_func(struct vm_area_struct *vma, - unsigned long address, unsigned int flags) +void my_direct_func(struct vm_area_struct *vma, unsigned long address, + unsigned int flags, struct pt_regs *regs) { - trace_printk("handle mm fault vma=%p address=%lx flags=%x\n", - vma, address, flags); + trace_printk("handle mm fault vma=%p address=%lx flags=%x regs=%p\n", + vma, address, flags, regs); }

extern void my_tramp(void *); @@ -34,7 +34,9 @@ asm ( " pushq %rdi\n" " pushq %rsi\n" " pushq %rdx\n" +" pushq %rcx\n" " call my_direct_func\n" +" popq %rcx\n" " popq %rdx\n" " popq %rsi\n" " popq %rdi\n"