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Subject[PATCH 1/5] x86/entry: introduce macro idtentry_swapgs_and_switch_to_kernel_stack
Date
Move a portion of code to be a macro, and it will also be used in
next patch.

Just move around the code, no functionality changed.

Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
---
arch/x86/entry/entry_64.S | 60 ++++++++++++++++++++++++++-------------
1 file changed, 41 insertions(+), 19 deletions(-)

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index d983a0d4bc73..5e983506f82e 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -698,28 +698,22 @@ SYM_CODE_END(\asmsym)
#include <asm/idtentry.h>

/*
- * Interrupt entry helper function.
+ * IDT entry helper macro for entering from userspace.
*
* Entry runs with interrupts off. Stack layout at entry:
- * +----------------------------------------------------+
- * | regs->ss |
- * | regs->rsp |
- * | regs->eflags |
- * | regs->cs |
- * | regs->ip |
- * +----------------------------------------------------+
- * | regs->orig_ax = ~(interrupt number) |
- * +----------------------------------------------------+
- * | return address |
- * +----------------------------------------------------+
+ * +--------------------+
+ * | regs->ss |
+ * | regs->rsp |
+ * | regs->eflags |
+ * | regs->cs |
+ * | regs->ip |
+ * | regs->orig_ax |
+ * | return address |
+ * +--------------------+
+ * The macro does swapgs and switches to current kernel stack with the
+ * same stack layout copied.
*/
-SYM_CODE_START(interrupt_entry)
- UNWIND_HINT_IRET_REGS offset=16
- ASM_CLAC
- cld
-
- testb $3, CS-ORIG_RAX+8(%rsp)
- jz 1f
+.macro idtentry_swapgs_and_switch_to_kernel_stack
SWAPGS
FENCE_SWAPGS_USER_ENTRY
/*
@@ -751,6 +745,34 @@ SYM_CODE_START(interrupt_entry)
pushq 8(%rdi) /* return address */

movq (%rdi), %rdi
+.endm
+
+/*
+ * Interrupt entry helper function.
+ *
+ * Entry runs with interrupts off. Stack layout at entry:
+ * +----------------------------------------------------+
+ * | regs->ss |
+ * | regs->rsp |
+ * | regs->eflags |
+ * | regs->cs |
+ * | regs->ip |
+ * +----------------------------------------------------+
+ * | regs->orig_ax = ~(interrupt number) |
+ * +----------------------------------------------------+
+ * | return address |
+ * +----------------------------------------------------+
+ */
+SYM_CODE_START(interrupt_entry)
+ UNWIND_HINT_IRET_REGS offset=16
+ ASM_CLAC
+ cld
+
+ testb $3, CS-ORIG_RAX+8(%rsp)
+ jz 1f
+
+ idtentry_swapgs_and_switch_to_kernel_stack
+
jmp 2f
1:
FENCE_SWAPGS_KERNEL_ENTRY
--
2.20.1
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