[RFC,-tip,1/3] x86/kprobes: Add ORC information to optprobe template

Commit Message

Masami Hiramatsu (Google) March 31, 2021, 5:44 a.m. UTC

As same as kretprobe_trampoline, move the optprobe template
code in the text for making ORC information on that.

Signed-off-by: Masami Hiramatsu <[e-mail]>
---
 arch/x86/kernel/kprobes/opt.c |   18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

Patch

diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c
index 4299fc865732..6d26e5cf2ba2 100644
--- a/arch/x86/kernel/kprobes/opt.c
+++ b/arch/x86/kernel/kprobes/opt.c
@@ -100,9 +100,13 @@  static void synthesize_set_arg1(kprobe_opcode_t *addr, unsigned long val)
 	*(unsigned long *)addr = val;
 }
 
+static void
+optimized_callback(struct optimized_kprobe *op, struct pt_regs *regs);
+
 asm (
-			".pushsection .rodata\n"
+			".text\n"
 			"optprobe_template_func:\n"
+			".type optprobe_template_func, @function\n"
 			".global optprobe_template_entry\n"
 			"optprobe_template_entry:\n"
 #ifdef CONFIG_X86_64
@@ -120,7 +124,8 @@  asm (
 			ASM_NOP5
 			".global optprobe_template_call\n"
 			"optprobe_template_call:\n"
-			ASM_NOP5
+			/* Dummy call for ORC */
+			"	callq optimized_callback\n"
 			/* Move flags to rsp */
 			"	movq 18*8(%rsp), %rdx\n"
 			"	movq %rdx, 19*8(%rsp)\n"
@@ -141,7 +146,8 @@  asm (
 			ASM_NOP5
 			".global optprobe_template_call\n"
 			"optprobe_template_call:\n"
-			ASM_NOP5
+			/* Dummy call for ORC */
+			"	call optimized_callback\n"
 			/* Move flags into esp */
 			"	movl 14*4(%esp), %edx\n"
 			"	movl %edx, 15*4(%esp)\n"
@@ -152,10 +158,12 @@  asm (
 #endif
 			".global optprobe_template_end\n"
 			"optprobe_template_end:\n"
-			".popsection\n");
+			/* Dummy return for objtool */
+			"	ret\n"
+			".size optprobe_template_func, .-optprobe_template_func\n"
+);
 
 void optprobe_template_func(void);
-STACK_FRAME_NON_STANDARD(optprobe_template_func);
 
 #define TMPL_CLAC_IDX \
 	((long)optprobe_template_clac - (long)optprobe_template_entry)