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-rw-r--r--arch/um/sys-x86_64/stub.S50
1 files changed, 40 insertions, 10 deletions
diff --git a/arch/um/sys-x86_64/stub.S b/arch/um/sys-x86_64/stub.S
index 957f2eff32ca..03c279735784 100644
--- a/arch/um/sys-x86_64/stub.S
+++ b/arch/um/sys-x86_64/stub.S
@@ -16,21 +16,51 @@ syscall_stub:
.globl batch_syscall_stub
batch_syscall_stub:
- movq $(UML_CONFIG_STUB_DATA >> 32), %rbx
- salq $32, %rbx
- movq $(UML_CONFIG_STUB_DATA & 0xffffffff), %rcx
- or %rcx, %rbx
- movq %rbx, %rsp
-again: pop %rax
- cmpq $0, %rax
-jz done
+ mov $(UML_CONFIG_STUB_DATA >> 32), %rbx
+ sal $32, %rbx
+ mov $(UML_CONFIG_STUB_DATA & 0xffffffff), %rax
+ or %rax, %rbx
+ /* load pointer to first operation */
+ mov %rbx, %rsp
+ add $0x10, %rsp
+again:
+ /* load length of additional data */
+ mov 0x0(%rsp), %rax
+
+ /* if(length == 0) : end of list */
+ /* write possible 0 to header */
+ mov %rax, 8(%rbx)
+ cmp $0, %rax
+ jz done
+
+ /* save current pointer */
+ mov %rsp, 8(%rbx)
+
+ /* skip additional data */
+ add %rax, %rsp
+
+ /* load syscall-# */
+ pop %rax
+
+ /* load syscall params */
pop %rdi
pop %rsi
pop %rdx
pop %r10
pop %r8
pop %r9
+
+ /* execute syscall */
syscall
+
+ /* check return value */
+ pop %rcx
+ cmp %rcx, %rax
+ je again
+
+done:
+ /* save return value */
mov %rax, (%rbx)
- jmp again
-done: int3
+
+ /* stop */
+ int3
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