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authorPeter Zijlstra <peterz@infradead.org>2021-10-30 09:47:58 +0200
committerPeter Zijlstra <peterz@infradead.org>2021-11-11 13:09:31 +0100
commit2105a92748e83e2e3ee6be539da959706bbb3898 (patch)
tree04dd3c3a9a55be81189d30054b015b2587dc5968 /tools
parentdebe436e77c72fcee804fb867f275e6d31aa999c (diff)
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static_call,x86: Robustify trampoline patching
Add a few signature bytes after the static call trampoline and verify those bytes match before patching the trampoline. This avoids patching random other JMPs (such as CFI jump-table entries) instead. These bytes decode as: d: 53 push %rbx e: 43 54 rex.XB push %r12 And happen to spell "SCT". Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20211030074758.GT174703@worktop.programming.kicks-ass.net
Diffstat (limited to 'tools')
-rw-r--r--tools/objtool/check.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/tools/objtool/check.c b/tools/objtool/check.c
index add39902166d..21735829b860 100644
--- a/tools/objtool/check.c
+++ b/tools/objtool/check.c
@@ -3310,6 +3310,9 @@ static bool ignore_unreachable_insn(struct objtool_file *file, struct instructio
if (!insn->func)
return false;
+ if (insn->func->static_call_tramp)
+ return true;
+
/*
* CONFIG_UBSAN_TRAP inserts a UD2 when it sees
* __builtin_unreachable(). The BUG() macro has an unreachable() after