From: Kees Cook <keesc...@chromium.org>
Instead of using inline asm for the int3 selftest (which confuses the
Clang's ThinLTO pass), this restores the C function but disables KASAN
(and tracing for good measure) to keep the things simple and avoid
unexpected side-effects. This attempts to keep the fix from commit
ecc606103837 ("x86/alternatives: Fix int3_emulate_call() selftest stack
corruption") without using inline asm.
Signed-off-by: Kees Cook <keesc...@chromium.org>
Signed-off-by: Sami Tolvanen <samitolva...@google.com>
---
arch/x86/kernel/alternative.c | 21 ++++-----------------
1 file changed, 4 insertions(+), 17 deletions(-)
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 6974b5174495..669a23454c09 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -496,23 +496,10 @@ extern struct paravirt_patch_site
__start_parainstructions[],
*
* See entry_{32,64}.S for more details.
*/
-
-/*
- * We define the int3_magic() function in assembly to control the calling
- * convention such that we can 'call' it from assembly.
- */
-
-extern void int3_magic(unsigned int *ptr); /* defined in asm */
-
-asm (
-" .pushsection .init.text, \"ax\", @progbits\n"
-" .type int3_magic, @function\n"
-"int3_magic:\n"
-" movl $1, (%" _ASM_ARG1 ")\n"
-" ret\n"
-" .size int3_magic, .-int3_magic\n"
-" .popsection\n"
-);
+static void __init __no_sanitize_address notrace int3_magic(unsigned int *ptr)
+{
+ *ptr = 1;
+}
extern __initdata unsigned long int3_selftest_ip; /* defined in asm below */
--
2.31.1.368.gbe11c130af-goog
