xref: /linux/arch/arm/kernel/entry-header.S (revision de2fe5e07d58424bc286fff3fd3c1b0bf933cd58)
1#include <linux/config.h>
2#include <linux/init.h>
3#include <linux/linkage.h>
4
5#include <asm/assembler.h>
6#include <asm/asm-offsets.h>
7#include <asm/errno.h>
8#include <asm/thread_info.h>
9
10@ Bad Abort numbers
11@ -----------------
12@
13#define BAD_PREFETCH	0
14#define BAD_DATA	1
15#define BAD_ADDREXCPTN	2
16#define BAD_IRQ		3
17#define BAD_UNDEFINSTR	4
18
19@
20@ Most of the stack format comes from struct pt_regs, but with
21@ the addition of 8 bytes for storing syscall args 5 and 6.
22@ This _must_ remain a multiple of 8 for EABI.
23@
24#define S_OFF		8
25
26/*
27 * The SWI code relies on the fact that R0 is at the bottom of the stack
28 * (due to slow/fast restore user regs).
29 */
30#if S_R0 != 0
31#error "Please fix"
32#endif
33
34	.macro	zero_fp
35#ifdef CONFIG_FRAME_POINTER
36	mov	fp, #0
37#endif
38	.endm
39
40	.macro	get_thread_info, rd
41	mov	\rd, sp, lsr #13
42	mov	\rd, \rd, lsl #13
43	.endm
44
45	.macro	alignment_trap, rtemp
46#ifdef CONFIG_ALIGNMENT_TRAP
47	ldr	\rtemp, .LCcralign
48	ldr	\rtemp, [\rtemp]
49	mcr	p15, 0, \rtemp, c1, c0
50#endif
51	.endm
52
53
54/*
55 * These are the registers used in the syscall handler, and allow us to
56 * have in theory up to 7 arguments to a function - r0 to r6.
57 *
58 * r7 is reserved for the system call number for thumb mode.
59 *
60 * Note that tbl == why is intentional.
61 *
62 * We must set at least "tsk" and "why" when calling ret_with_reschedule.
63 */
64scno	.req	r7		@ syscall number
65tbl	.req	r8		@ syscall table pointer
66why	.req	r8		@ Linux syscall (!= 0)
67tsk	.req	r9		@ current thread_info
68