xref: /openbmc/linux/arch/x86/um/stub_32.S (revision e40573a4)
1/* SPDX-License-Identifier: GPL-2.0 */
2#include <as-layout.h>
3
4.section .__syscall_stub, "ax"
5
6	.globl batch_syscall_stub
7batch_syscall_stub:
8	/* %esp comes in as "top of page" */
9	mov %esp, %ecx
10	/* %esp has pointer to first operation */
11	add $8, %esp
12again:
13	/* load length of additional data */
14	mov	0x0(%esp), %eax
15
16	/* if(length == 0) : end of list */
17	/* write possible 0 to header */
18	mov	%eax, 0x4(%ecx)
19	cmpl	$0, %eax
20	jz	done
21
22	/* save current pointer */
23	mov	%esp, 0x4(%ecx)
24
25	/* skip additional data */
26	add	%eax, %esp
27
28	/* load syscall-# */
29	pop	%eax
30
31	/* load syscall params */
32	pop	%ebx
33	pop	%ecx
34	pop	%edx
35	pop	%esi
36 	pop	%edi
37	pop	%ebp
38
39	/* execute syscall */
40	int	$0x80
41
42	/* restore top of page pointer in %ecx */
43	mov	%esp, %ecx
44	andl	$(~UM_KERN_PAGE_SIZE) + 1, %ecx
45
46	/* check return value */
47	pop	%ebx
48	cmp	%ebx, %eax
49	je	again
50
51done:
52	/* save return value */
53	mov	%eax, (%ecx)
54
55	/* stop */
56	int3
57