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-rw-r--r--arch/x86/entry/entry_64.S15
1 files changed, 15 insertions, 0 deletions
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 5422bd20bdf4..8cb3e438f21e 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -1454,6 +1454,21 @@ first_nmi:
/* Everything up to here is safe from nested NMIs */
+#ifdef CONFIG_DEBUG_ENTRY
+ /*
+ * For ease of testing, unmask NMIs right away. Disabled by
+ * default because IRET is very expensive.
+ */
+ pushq $0 /* SS */
+ pushq %rsp /* RSP (minus 8 because of the previous push) */
+ addq $8, (%rsp) /* Fix up RSP */
+ pushfq /* RFLAGS */
+ pushq $__KERNEL_CS /* CS */
+ pushq $1f /* RIP */
+ INTERRUPT_RETURN /* continues at repeat_nmi below */
+1:
+#endif
+
repeat_nmi:
/*
* If there was a nested NMI, the first NMI's iret will return