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-rw-r--r--arch/x86/um/stub_64.S66
1 files changed, 66 insertions, 0 deletions
diff --git a/arch/x86/um/stub_64.S b/arch/x86/um/stub_64.S
new file mode 100644
index 000000000000..20e4a96a6dcb
--- /dev/null
+++ b/arch/x86/um/stub_64.S
@@ -0,0 +1,66 @@
+#include "as-layout.h"
+
+ .globl syscall_stub
+.section .__syscall_stub, "ax"
+syscall_stub:
+ syscall
+ /* We don't have 64-bit constants, so this constructs the address
+ * we need.
+ */
+ movq $(STUB_DATA >> 32), %rbx
+ salq $32, %rbx
+ movq $(STUB_DATA & 0xffffffff), %rcx
+ or %rcx, %rbx
+ movq %rax, (%rbx)
+ int3
+
+ .globl batch_syscall_stub
+batch_syscall_stub:
+ mov $(STUB_DATA >> 32), %rbx
+ sal $32, %rbx
+ mov $(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)
+
+ /* stop */
+ int3