xref: /openbmc/linux/arch/arm/kernel/entry-header.S (revision 87c2ce3b)
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@
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, rtemp
63#ifdef CONFIG_ALIGNMENT_TRAP
64	ldr	\rtemp, .LCcralign
65	ldr	\rtemp, [\rtemp]
66	mcr	p15, 0, \rtemp, c1, c0
67#endif
68	.endm
69
70
71/*
72 * These are the registers used in the syscall handler, and allow us to
73 * have in theory up to 7 arguments to a function - r0 to r6.
74 *
75 * r7 is reserved for the system call number for thumb mode.
76 *
77 * Note that tbl == why is intentional.
78 *
79 * We must set at least "tsk" and "why" when calling ret_with_reschedule.
80 */
81scno	.req	r7		@ syscall number
82tbl	.req	r8		@ syscall table pointer
83why	.req	r8		@ Linux syscall (!= 0)
84tsk	.req	r9		@ current thread_info
85