Commit-ID: deecd4d71b12626db48544faa66bb897e2cafd07
Gitweb: http://git.kernel.org/tip/deecd4d71b12626db48544faa66bb897e2cafd07
Author: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
AuthorDate: Thu, 27 Jul 2017 15:56:55 -0500
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Mon, 21 Aug 2017 16:07:27 +0200
objtool: Fix '-mtune=atom' decoding support in objtool 2.0
With '-mtune=atom', which is enabled with CONFIG_MATOM=y, GCC uses some
unusual instructions for setting up the stack.
Instead of:
mov %rsp, %rbp
it does:
lea (%rsp), %rbp
And instead of:
add imm, %rsp
it does:
lea disp(%rsp), %rsp
Add support for these instructions to the objtool decoder.
Reported-by: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Fixes: baa41469a7b9 ("objtool: Implement stack validation 2.0")
Link: http://lkml.kernel.org/r/4ea1db896e821226efe1f8e09f270771bde47e65.1501188854.git.jpoimboe@xxxxxxxxxx
[ This is a cherry-picked version of upcoming commit 5b8de48e82ba. ]
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
tools/objtool/arch/x86/decode.c | 26 +++++++++++++++++++++++++-
1 file changed, 25 insertions(+), 1 deletion(-)
diff --git a/tools/objtool/arch/x86/decode.c b/tools/objtool/arch/x86/decode.c
index a36c2eb..4559a21a 100644
--- a/tools/objtool/arch/x86/decode.c
+++ b/tools/objtool/arch/x86/decode.c
@@ -271,7 +271,7 @@ int arch_decode_instruction(struct elf *elf, struct section *sec,
case 0x8d:
if (rex == 0x48 && modrm == 0x65) {
- /* lea -disp(%rbp), %rsp */
+ /* lea disp(%rbp), %rsp */
*type = INSN_STACK;
op->src.type = OP_SRC_ADD;
op->src.reg = CFI_BP;
@@ -281,6 +281,30 @@ int arch_decode_instruction(struct elf *elf, struct section *sec,
break;
}
+ if (rex == 0x48 && (modrm == 0xa4 || modrm == 0x64) &&
+ sib == 0x24) {
+
+ /* lea disp(%rsp), %rsp */
+ *type = INSN_STACK;
+ op->src.type = OP_SRC_ADD;
+ op->src.reg = CFI_SP;
+ op->src.offset = insn.displacement.value;
+ op->dest.type = OP_DEST_REG;
+ op->dest.reg = CFI_SP;
+ break;
+ }
+
+ if (rex == 0x48 && modrm == 0x2c && sib == 0x24) {
+
+ /* lea (%rsp), %rbp */
+ *type = INSN_STACK;
+ op->src.type = OP_SRC_REG;
+ op->src.reg = CFI_SP;
+ op->dest.type = OP_DEST_REG;
+ op->dest.reg = CFI_BP;
+ break;
+ }
+
if (rex == 0x4c && modrm == 0x54 && sib == 0x24 &&
insn.displacement.value == 8) {
--
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