[Xen-devel] [PATCH V2 2/6] mini-os/x86-64 entry: define macros for registers partial save and restore; no functional changes

[Xu Zhang <xzhang@xxxxxxxxxx>]

For saving and restoring registers rbx, rbp, and r12-r15,
define and use macros SAVE_REST and RESTORE_REST respectively.

Signed-off-by: Xu Zhang <xzhang@xxxxxxxxxx>
---
 extras/mini-os/arch/x86/x86_64.S |   37 ++++++++++++++++++++++---------------
 1 files changed, 22 insertions(+), 15 deletions(-)

diff --git a/extras/mini-os/arch/x86/x86_64.S b/extras/mini-os/arch/x86/x86_64.S
index 79099f1..24f35cd 100644
--- a/extras/mini-os/arch/x86/x86_64.S
+++ b/extras/mini-os/arch/x86/x86_64.S
@@ -59,6 +59,25 @@ NMI_MASK = 0x80000000
        addq $9*8+8,%rsp
 .endm  
 
+.macro RESTORE_REST
+       movq (%rsp),%r15
+       movq 1*8(%rsp),%r14
+       movq 2*8(%rsp),%r13
+       movq 3*8(%rsp),%r12
+       movq 4*8(%rsp),%rbp
+       movq 5*8(%rsp),%rbx
+       addq $6*8,%rsp
+.endm
+
+.macro SAVE_REST
+       subq $6*8,%rsp
+       movq %rbx,5*8(%rsp)
+       movq %rbp,4*8(%rsp)
+       movq %r12,3*8(%rsp)
+       movq %r13,2*8(%rsp)
+       movq %r14,1*8(%rsp)
+       movq %r15,(%rsp)
+.endm
 
 .macro HYPERVISOR_IRET flag
        testl $NMI_MASK,2*8(%rsp)
@@ -173,13 +192,7 @@ scrit:     /**** START OF CRITICAL REGION ****/
 
 14:    XEN_LOCKED_BLOCK_EVENTS(%rsi)
        XEN_PUT_VCPU_INFO(%rsi)
-       subq $6*8,%rsp
-       movq %rbx,5*8(%rsp)
-       movq %rbp,4*8(%rsp)
-       movq %r12,3*8(%rsp)
-       movq %r13,2*8(%rsp)
-       movq %r14,1*8(%rsp)
-       movq %r15,(%rsp)
+       SAVE_REST
        movq %rsp,%rdi                  # set the argument again
        jmp  11b
 ecrit:  /**** END OF CRITICAL REGION ****/
@@ -199,14 +212,8 @@ retint_restore_args:
        HYPERVISOR_IRET 0
 
 
-error_exit:            
-       movq (%rsp),%r15
-       movq 1*8(%rsp),%r14
-       movq 2*8(%rsp),%r13
-       movq 3*8(%rsp),%r12
-       movq 4*8(%rsp),%rbp
-       movq 5*8(%rsp),%rbx
-       addq $6*8,%rsp
+error_exit:
+       RESTORE_REST
        XEN_BLOCK_EVENTS(%rsi)          
        jmp retint_kernel
 
-- 
1.7.7.6


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