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authorBorislav Petkov (AMD) <bp@alien8.de>2023-05-15 17:07:26 +0300
committerBorislav Petkov (AMD) <bp@alien8.de>2023-05-17 13:14:21 +0300
commitf220125b999b2c9694149c6bda2798d8096f47ed (patch)
tree7cee09cfdcadf0a27866192d98be136f3a388130 /arch/x86/lib/retpoline.S
parent7583e8fbdc49a4dbd916d14863cf1deeddb982f9 (diff)
downloadlinux-f220125b999b2c9694149c6bda2798d8096f47ed.tar.xz
x86/retbleed: Add __x86_return_thunk alignment checks
Add a linker assertion and compute the 0xcc padding dynamically so that __x86_return_thunk is always cacheline-aligned. Leave the SYM_START() macro in as the untraining doesn't need ENDBR annotations anyway. Suggested-by: Andrew Cooper <andrew.cooper3@citrix.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com> Link: https://lore.kernel.org/r/20230515140726.28689-1-bp@alien8.de
Diffstat (limited to 'arch/x86/lib/retpoline.S')
-rw-r--r--arch/x86/lib/retpoline.S2
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/lib/retpoline.S b/arch/x86/lib/retpoline.S
index b3b1e376dce8..3fd066d42ec0 100644
--- a/arch/x86/lib/retpoline.S
+++ b/arch/x86/lib/retpoline.S
@@ -143,7 +143,7 @@ SYM_CODE_END(__x86_indirect_jump_thunk_array)
* from re-poisioning the BTB prediction.
*/
.align 64
- .skip 63, 0xcc
+ .skip 64 - (__x86_return_thunk - zen_untrain_ret), 0xcc
SYM_START(zen_untrain_ret, SYM_L_GLOBAL, SYM_A_NONE)
ANNOTATE_NOENDBR
/*