[PATCH 6.6 389/396] Revert "x86/bugs: Use fixed addressing for VERW operand"

Greg Kroah-Hartman
2024-04-01T16:55:51Z

From: Dave Hansen <dave.hansen@linux.intel.com>

commit 532a0c57d7ff75e8f07d4e25cba4184989e2a241 upstream.

This was reverts commit 8009479ee919b9a91674f48050ccbff64eafedaa.

It was originally in x86/urgent, but was deemed wrong so got zapped.
But in the meantime, x86/urgent had been merged into x86/apic to
resolve a conflict. I didn't notice the merge so didn't zap it
from x86/apic and it managed to make it up with the x86/apic
material.

The reverted commit is known to cause some KASAN problems.

Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/nospec-branch.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -337,7 +337,7 @@
* Note: Only the memory operand variant of VERW clears the CPU buffers.
*/
.macro CLEAR_CPU_BUFFERS
- ALTERNATIVE "", __stringify(verw mds_verw_sel), X86_FEATURE_CLEAR_CPU_BUF
+ ALTERNATIVE "", __stringify(verw _ASM_RIP(mds_verw_sel)), X86_FEATURE_CLEAR_CPU_BUF
.endm

#else /* __ASSEMBLY__ */