[tip:x86/asmlinkage] x86, asmlinkage: Make kprobes code visible and fix assembler code

From: tip-bot for Andi Kleen
Date: Tue Aug 06 2013 - 17:47:39 EST


Commit-ID: 04bb591ca74fb8ea06d5ab7fadfb7bf5b11fb28e
Gitweb: http://git.kernel.org/tip/04bb591ca74fb8ea06d5ab7fadfb7bf5b11fb28e
Author: Andi Kleen <ak@xxxxxxxxxxxxxxx>
AuthorDate: Mon, 5 Aug 2013 15:02:41 -0700
Committer: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
CommitDate: Tue, 6 Aug 2013 14:19:48 -0700

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@xxxxxxxxxx>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@xxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1375740170-7446-8-git-send-email-andi@xxxxxxxxxxxxxx
Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxxxxxxxx>
---
arch/x86/include/asm/kprobes.h | 10 +++++-----
arch/x86/kernel/kprobes/core.c | 2 +-
arch/x86/kernel/kprobes/opt.c | 5 +----
3 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/arch/x86/include/asm/kprobes.h b/arch/x86/include/asm/kprobes.h
index 5a6d287..9454c16 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 211bce4..048852d 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 76dc6f0..2c1ac28 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)
--
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