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Subject[PATCH 2/5] x86: Add symbolic constant for exceptions with error code
Date
From: "H. Peter Anvin" <hpa@zytor.com>

Add a symbolic constant for the bitmask which states which exceptions
carry an error code.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
---
arch/x86/include/asm/segment.h | 2 ++
arch/x86/kernel/head_64.S | 2 +-
2 files changed, 3 insertions(+), 1 deletions(-)
diff --git a/arch/x86/include/asm/segment.h b/arch/x86/include/asm/segment.h
index 1654662..58c1e6c 100644
--- a/arch/x86/include/asm/segment.h
+++ b/arch/x86/include/asm/segment.h
@@ -205,6 +205,8 @@

#define IDT_ENTRIES 256
#define NUM_EXCEPTION_VECTORS 32
+/* Bitmask of exception vectors which push an error code on the stack */
+#define EXCEPTION_ERRCODE_MASK 0x00027d00
#define GDT_SIZE (GDT_ENTRIES * 8)
#define GDT_ENTRY_TLS_ENTRIES 3
#define TLS_SIZE (GDT_ENTRY_TLS_ENTRIES * 8)
diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S
index 40f4eb3..adf52e8 100644
--- a/arch/x86/kernel/head_64.S
+++ b/arch/x86/kernel/head_64.S
@@ -295,7 +295,7 @@ ENTRY(early_idt_handler)
ja 0f
movl $1,%eax
salq %cl,%rax
- testl $0x27d00,%eax
+ testl $EXCEPTION_ERRCODE_MASK,%eax
je 0f
popq %r8 # get error code
0: movq 0(%rsp),%rcx # get ip
--
1.7.6.5


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