xref: /linux/arch/arm/kernel/entry-header.S (revision 776cfebb430c7b22c208b1b17add97f354d97cab)
1#include <linux/config.h>
2#include <linux/init.h>
3#include <linux/linkage.h>
4
5#include <asm/assembler.h>
6#include <asm/constants.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@
23#define S_OFF		8
24
25/*
26 * The SWI code relies on the fact that R0 is at the bottom of the stack
27 * (due to slow/fast restore user regs).
28 */
29#if S_R0 != 0
30#error "Please fix"
31#endif
32
33	.macro	zero_fp
34#ifdef CONFIG_FRAME_POINTER
35	mov	fp, #0
36#endif
37	.endm
38
39#if __LINUX_ARM_ARCH__ >= 6
40	.macro	disable_irq
41	cpsid	i
42	.endm
43
44	.macro	enable_irq
45	cpsie	i
46	.endm
47#else
48	.macro	disable_irq
49	msr	cpsr_c, #PSR_I_BIT | SVC_MODE
50	.endm
51
52	.macro	enable_irq
53	msr	cpsr_c, #SVC_MODE
54	.endm
55#endif
56
57	.macro	get_thread_info, rd
58	mov	\rd, sp, lsr #13
59	mov	\rd, \rd, lsl #13
60	.endm
61
62	.macro	alignment_trap, rbase, rtemp, sym
63#ifdef CONFIG_ALIGNMENT_TRAP
64#define OFF_CR_ALIGNMENT(x)	cr_alignment - x
65
66	ldr	\rtemp, [\rbase, #OFF_CR_ALIGNMENT(\sym)]
67	mcr	p15, 0, \rtemp, c1, c0
68#endif
69	.endm
70
71
72/*
73 * These are the registers used in the syscall handler, and allow us to
74 * have in theory up to 7 arguments to a function - r0 to r6.
75 *
76 * r7 is reserved for the system call number for thumb mode.
77 *
78 * Note that tbl == why is intentional.
79 *
80 * We must set at least "tsk" and "why" when calling ret_with_reschedule.
81 */
82scno	.req	r7		@ syscall number
83tbl	.req	r8		@ syscall table pointer
84why	.req	r8		@ Linux syscall (!= 0)
85tsk	.req	r9		@ current thread_info
86