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-rw-r--r--arch/x86/entry/entry_64.S13
1 files changed, 13 insertions, 0 deletions
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index db5009ce065a..8d7e4d48db0d 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -176,13 +176,26 @@ GLOBAL(entry_SYSCALL_64_after_swapgs)
pushq %r8 /* pt_regs->r8 */
pushq %r9 /* pt_regs->r9 */
pushq %r10 /* pt_regs->r10 */
+ /*
+ * Clear extra registers that a speculation attack might
+ * otherwise want to exploit. Interleave XOR with PUSH
+ * for better uop scheduling:
+ */
+ xorq %r10, %r10 /* nospec r10 */
pushq %r11 /* pt_regs->r11 */
+ xorq %r11, %r11 /* nospec r11 */
pushq %rbx /* pt_regs->rbx */
+ xorl %ebx, %ebx /* nospec rbx */
pushq %rbp /* pt_regs->rbp */
+ xorl %ebp, %ebp /* nospec rbp */
pushq %r12 /* pt_regs->r12 */
+ xorq %r12, %r12 /* nospec r12 */
pushq %r13 /* pt_regs->r13 */
+ xorq %r13, %r13 /* nospec r13 */
pushq %r14 /* pt_regs->r14 */
+ xorq %r14, %r14 /* nospec r14 */
pushq %r15 /* pt_regs->r15 */
+ xorq %r15, %r15 /* nospec r15 */
/* IRQs are off. */
movq %rsp, %rdi