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authorBorislav Petkov (AMD) <bp@alien8.de>2023-05-13 00:12:26 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2023-05-13 01:19:53 +0300
commit9a48d604672220545d209e9996c2a1edbb5637f6 (patch)
tree8e6235d2df95972cc333f43e406f39f70d6b6f2f /arch
parent76c7f8873a7696dbd8f9cd844e30e5c84cbaba1a (diff)
downloadlinux-9a48d604672220545d209e9996c2a1edbb5637f6.tar.xz
x86/retbleed: Fix return thunk alignment
SYM_FUNC_START_LOCAL_NOALIGN() adds an endbr leading to this layout (leaving only the last 2 bytes of the address): 3bff <zen_untrain_ret>: 3bff: f3 0f 1e fa endbr64 3c03: f6 test $0xcc,%bl 3c04 <__x86_return_thunk>: 3c04: c3 ret 3c05: cc int3 3c06: 0f ae e8 lfence However, "the RET at __x86_return_thunk must be on a 64 byte boundary, for alignment within the BTB." Use SYM_START instead. Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: <stable@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/lib/retpoline.S4
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S
index 27ef53fab6bd..b3b1e376dce8 100644
--- a/arch/x86/lib/retpoline.S
+++ b/arch/x86/lib/retpoline.S
@@ -144,8 +144,8 @@ SYM_CODE_END(__x86_indirect_jump_thunk_array)
*/
.align 64
.skip 63, 0xcc
-SYM_FUNC_START_NOALIGN(zen_untrain_ret);
-
+SYM_START(zen_untrain_ret, SYM_L_GLOBAL, SYM_A_NONE)
+ ANNOTATE_NOENDBR
/*
* As executed from zen_untrain_ret, this is:
*