x86, asmlinkage: Make kprobes code visible and fix assembler code

- 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 N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1375740170-7446-8-git-send-email-andi@firstfloor.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

3 files changed, 7 insertions, 10 deletions

diff --git a/arch/x86/include/asm/kprobes.h b/arch/x86/include/asm/kprobes.h
index 5a6d2873f80e..9454c167629f 100644
--- a/arch/x86/include/asm/kprobes.h
+++ b/arch/x86/include/asm/kprobes.h
@@ -49,10 +49,10 @@ 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 -       \
@@ -62,7 +62,7 @@ extern kprobe_opcode_t optprobe_template_end;
 extern const int kretprobe_blacklist_size;
 
 void arch_remove_kprobe(struct kprobe *p);
-void kretprobe_trampoline(void);
+asmlinkage void kretprobe_trampoline(void);
 
 /* Architecture specific copy of original instruction*/
 struct arch_specific_insn {
diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index 211bce445522..048852d06447 100644
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -661,7 +661,7 @@ static void __used __kprobes kretprobe_trampoline_holder(void)
 /*
  * Called from kretprobe_trampoline
  */
-static __used __kprobes void *trampoline_handler(struct pt_regs *regs)
+__visible __used __kprobes void *trampoline_handler(struct pt_regs *regs)
 {
         struct kretprobe_instance *ri = NULL;
         struct hlist_head *head, empty_rp;
diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c
index 76dc6f095724..2c1ac2893365 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)