* [PATCH] objtool: ignore INT3 padding
@ 2018-05-14 22:35 Alexey Dobriyan
2018-05-15 8:02 ` Peter Zijlstra
0 siblings, 1 reply; 2+ messages in thread
From: Alexey Dobriyan @ 2018-05-14 22:35 UTC (permalink / raw)
To: jpoimboe, peterz, mingo; +Cc: linux-kernel
NOP padding doesn't count as unreachable instruction
neither should INT3.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
---
tools/objtool/arch.h | 3 ++-
tools/objtool/arch/x86/decode.c | 4 ++++
tools/objtool/check.c | 3 +++
3 files changed, 9 insertions(+), 1 deletion(-)
--- a/tools/objtool/arch.h
+++ b/tools/objtool/arch.h
@@ -34,7 +34,8 @@
#define INSN_BUG 9
#define INSN_NOP 10
#define INSN_OTHER 11
-#define INSN_LAST INSN_OTHER
+#define INSN_INT3 12
+#define INSN_LAST INSN_INT3
enum op_dest_type {
OP_DEST_REG,
--- a/tools/objtool/arch/x86/decode.c
+++ b/tools/objtool/arch/x86/decode.c
@@ -440,6 +440,10 @@ int arch_decode_instruction(struct elf *elf, struct section *sec,
*type = INSN_CONTEXT_SWITCH;
break;
+ case 0xcc:
+ *type = INSN_INT3;
+ break;
+
case 0xe8:
*type = INSN_CALL;
break;
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -1998,6 +1998,9 @@ static bool ignore_unreachable_insn(struct instruction *insn)
if (insn->ignore || insn->type == INSN_NOP)
return true;
+ /* Inter-function padding. */
+ if (insn->type == INSN_INT3)
+ return true;
/*
* Ignore any unused exceptions. This can happen when a whitelisted
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH] objtool: ignore INT3 padding
2018-05-14 22:35 [PATCH] objtool: ignore INT3 padding Alexey Dobriyan
@ 2018-05-15 8:02 ` Peter Zijlstra
0 siblings, 0 replies; 2+ messages in thread
From: Peter Zijlstra @ 2018-05-15 8:02 UTC (permalink / raw)
To: Alexey Dobriyan; +Cc: jpoimboe, mingo, linux-kernel
On Tue, May 15, 2018 at 01:35:04AM +0300, Alexey Dobriyan wrote:
> NOP padding doesn't count as unreachable instruction
> neither should INT3.
Josh already did a patch for that, but I now realize that never hit
lkml.
https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?id=158754d60cdb824383c44a79d2166d5344c7a395
^ permalink raw reply [flat|nested] 2+ messages in thread
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