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Subject[PATCH 47/74] x86, lto: Fix kprobes for LTO
Date
From: Andi Kleen <ak@linux.intel.com>

- Make all the external assembler template symbols __visible
- Move the templates inline assembler code into a top level
assembler statement, not inside a function. This avoids it being
optimized away or cloned.

Cc: ananth@in.ibm.com
Signed-off-by: Andi Kleen <ak@linux.intel.com>
---
arch/x86/include/asm/kprobes.h | 8 ++++----
arch/x86/kernel/kprobes-opt.c | 5 +----
2 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/arch/x86/include/asm/kprobes.h b/arch/x86/include/asm/kprobes.h
index a967173..fa2d12e 100644
--- a/arch/x86/include/asm/kprobes.h
+++ b/arch/x86/include/asm/kprobes.h
@@ -48,10 +48,10 @@ typedef u8 kprobe_opcode_t;
#define flush_insn_slot(p) do { } while (0)

/* optinsn template addresses */
-extern kprobe_opcode_t optprobe_template_entry;
-extern kprobe_opcode_t optprobe_template_val;
-extern kprobe_opcode_t optprobe_template_call;
-extern kprobe_opcode_t optprobe_template_end;
+extern __visible kprobe_opcode_t optprobe_template_entry;
+extern __visible kprobe_opcode_t optprobe_template_val;
+extern __visible kprobe_opcode_t optprobe_template_call;
+extern __visible kprobe_opcode_t optprobe_template_end;
#define MAX_OPTIMIZED_LENGTH (MAX_INSN_SIZE + RELATIVE_ADDR_SIZE)
#define MAX_OPTINSN_SIZE \
(((unsigned long)&optprobe_template_end - \
diff --git a/arch/x86/kernel/kprobes-opt.c b/arch/x86/kernel/kprobes-opt.c
index c5e410e..43c34e8 100644
--- a/arch/x86/kernel/kprobes-opt.c
+++ b/arch/x86/kernel/kprobes-opt.c
@@ -88,9 +88,7 @@ static void __kprobes synthesize_set_arg1(kprobe_opcode_t *addr, unsigned long v
*(unsigned long *)addr = val;
}

-static void __used __kprobes kprobes_optinsn_template_holder(void)
-{
- asm volatile (
+asm (
".global optprobe_template_entry\n"
"optprobe_template_entry:\n"
#ifdef CONFIG_X86_64
@@ -129,7 +127,6 @@ static void __used __kprobes kprobes_optinsn_template_holder(void)
#endif
".global optprobe_template_end\n"
"optprobe_template_end:\n");
-}

#define TMPL_MOVE_IDX \
((long)&optprobe_template_val - (long)&optprobe_template_entry)
--
1.7.7.6


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