From: Florent Revest <revest@xxxxxxxxxxxx>
commit 8564c315876ab86fcaf8e7f558d6a84cb2ce5590 upstream.
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@xxxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx
Fixes: bce617edecad ("mm: do page fault accounting in handle_mm_fault")
Reviewed-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
Reviewed-by: Mark Rutland <mark.rutland@xxxxxxx>
Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Florent Revest <revest@xxxxxxxxxxxx>
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
samples/ftrace/ftrace-direct-too.c | 14 ++++++++------
1 file changed, 8 insertions(+), 6 deletions(-)
--- a/samples/ftrace/ftrace-direct-too.c
+++ b/samples/ftrace/ftrace-direct-too.c
@@ -4,14 +4,14 @@
#include <linux/mm.h> /* for handle_mm_fault() */
#include <linux/ftrace.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 *);
@@ -26,7 +26,9 @@ 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"
