xref: /openbmc/linux/arch/x86/um/stub_64.S (revision 4f3db074)
1#include <as-layout.h>
2
3	.globl syscall_stub
4.section .__syscall_stub, "ax"
5syscall_stub:
6	syscall
7	/* We don't have 64-bit constants, so this constructs the address
8	 * we need.
9	 */
10	movq	$(STUB_DATA >> 32), %rbx
11	salq	$32, %rbx
12	movq	$(STUB_DATA & 0xffffffff), %rcx
13	or	%rcx, %rbx
14	movq	%rax, (%rbx)
15	int3
16
17	.globl batch_syscall_stub
18batch_syscall_stub:
19	mov	$(STUB_DATA >> 32), %rbx
20	sal	$32, %rbx
21	mov	$(STUB_DATA & 0xffffffff), %rax
22	or	%rax, %rbx
23	/* load pointer to first operation */
24	mov	%rbx, %rsp
25	add	$0x10, %rsp
26again:
27	/* load length of additional data */
28	mov	0x0(%rsp), %rax
29
30	/* if(length == 0) : end of list */
31	/* write possible 0 to header */
32	mov	%rax, 8(%rbx)
33	cmp	$0, %rax
34	jz	done
35
36	/* save current pointer */
37	mov	%rsp, 8(%rbx)
38
39	/* skip additional data */
40	add	%rax, %rsp
41
42	/* load syscall-# */
43	pop	%rax
44
45	/* load syscall params */
46	pop	%rdi
47	pop	%rsi
48	pop	%rdx
49	pop	%r10
50 	pop	%r8
51	pop	%r9
52
53	/* execute syscall */
54	syscall
55
56	/* check return value */
57	pop	%rcx
58	cmp	%rcx, %rax
59	je	again
60
61done:
62	/* save return value */
63	mov	%rax, (%rbx)
64
65	/* stop */
66	int3
67