summaryrefslogtreecommitdiff
path: root/include
diff options
context:
space:
mode:
authorPeter Zijlstra <peterz@infradead.org>2023-08-02 12:55:46 +0200
committerIngo Molnar <mingo@kernel.org>2023-09-12 17:50:53 +0200
commit25e73b7e3f72a25aa30cbb2eecb49036e0acf066 (patch)
treeec51d86d83644e810a6ea761725bd6c344654dca /include
parent5290e88ba2c742ca77c5f5b690e5af549cfd8591 (diff)
x86/ibt: Suppress spurious ENDBR
It was reported that under certain circumstances GCC emits ENDBR instructions for _THIS_IP_ usage. Specifically, when it appears at the start of a basic block -- but not elsewhere. Since _THIS_IP_ is never used for control flow, these ENDBR instructions are completely superfluous. Override the _THIS_IP_ definition for x86_64 to avoid this. Less ENDBR instructions is better. Fixes: 156ff4a544ae ("x86/ibt: Base IBT bits") Reported-by: David Kaplan <David.Kaplan@amd.com> Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lore.kernel.org/r/20230802110323.016197440@infradead.org
Diffstat (limited to 'include')
-rw-r--r--include/linux/instruction_pointer.h5
1 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/instruction_pointer.h b/include/linux/instruction_pointer.h
index cda1f706eaeb..aa0b3ffea935 100644
--- a/include/linux/instruction_pointer.h
+++ b/include/linux/instruction_pointer.h
@@ -2,7 +2,12 @@
#ifndef _LINUX_INSTRUCTION_POINTER_H
#define _LINUX_INSTRUCTION_POINTER_H
+#include <asm/linkage.h>
+
#define _RET_IP_ (unsigned long)__builtin_return_address(0)
+
+#ifndef _THIS_IP_
#define _THIS_IP_ ({ __label__ __here; __here: (unsigned long)&&__here; })
+#endif
#endif /* _LINUX_INSTRUCTION_POINTER_H */