2 * linux/arch/arm/kernel/entry-common.S
4 * Copyright (C) 2000 Russell King
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
10 #include <linux/config.h>
12 #include <asm/unistd.h>
14 #include "entry-header.S"
19 * This is the fast syscall return path. We do as little as
20 * possible here, and this includes saving r0 back into the SVC
24 disable_irq @ disable interrupts
25 ldr r1, [tsk, #TI_FLAGS]
26 tst r1, #_TIF_WORK_MASK
29 @ fast_restore_user_regs
30 ldr r1, [sp, #S_OFF + S_PSR] @ get calling cpsr
31 ldr lr, [sp, #S_OFF + S_PC]! @ get pc
32 msr spsr_cxsf, r1 @ save in spsr_svc
33 ldmdb sp, {r1 - lr}^ @ get calling r1 - lr
35 add sp, sp, #S_FRAME_SIZE - S_PC
36 movs pc, lr @ return & move spsr_svc into cpsr
39 * Ok, we need to do extra processing, enter the slow path.
42 str r0, [sp, #S_R0+S_OFF]! @ returned r0
44 tst r1, #_TIF_NEED_RESCHED
46 tst r1, #_TIF_NOTIFY_RESUME | _TIF_SIGPENDING
49 mov r2, why @ 'syscall'
51 disable_irq @ disable interrupts
57 * "slow" syscall return path. "why" tells us if this was a real syscall.
61 disable_irq @ disable interrupts
62 ldr r1, [tsk, #TI_FLAGS]
63 tst r1, #_TIF_WORK_MASK
66 @ slow_restore_user_regs
67 ldr r1, [sp, #S_PSR] @ get calling cpsr
68 ldr lr, [sp, #S_PC]! @ get pc
69 msr spsr_cxsf, r1 @ save in spsr_svc
70 ldmdb sp, {r0 - lr}^ @ get calling r1 - lr
72 add sp, sp, #S_FRAME_SIZE - S_PC
73 movs pc, lr @ return & move spsr_svc into cpsr
76 * This is how we return from a fork.
81 ldr r1, [tsk, #TI_FLAGS] @ check for syscall tracing
83 tst r1, #_TIF_SYSCALL_TRACE @ are we tracing syscalls?
86 mov r0, #1 @ trace exit [IP = 1]
93 /*=============================================================================
95 *-----------------------------------------------------------------------------
98 /* If we're optimising for StrongARM the resulting code won't
99 run on an ARM7 and we can save a couple of instructions.
101 #ifdef CONFIG_CPU_ARM710
102 .macro arm710_bug_check, instr, temp
103 and \temp, \instr, #0x0f000000 @ check for SWI
104 teq \temp, #0x0f000000
109 ldmia sp, {r0 - lr}^ @ Get calling r0 - lr
111 add sp, sp, #S_FRAME_SIZE
114 .macro arm710_bug_check, instr, temp
120 sub sp, sp, #S_FRAME_SIZE
121 stmia sp, {r0 - r12} @ Calling r0 - r12
123 stmdb r8, {sp, lr}^ @ Calling sp, lr
124 mrs r8, spsr @ called from non-FIQ mode, so ok.
125 str lr, [sp, #S_PC] @ Save calling PC
126 str r8, [sp, #S_PSR] @ Save CPSR
127 str r0, [sp, #S_OLD_R0] @ Save OLD_R0
131 * Get the system call number.
133 #ifdef CONFIG_ARM_THUMB
134 tst r8, #PSR_T_BIT @ this is SPSR from save_user_regs
135 addne scno, r7, #__NR_SYSCALL_BASE @ put OS number in
136 ldreq scno, [lr, #-4]
138 ldr scno, [lr, #-4] @ get SWI instruction
140 arm710_bug_check scno, ip
142 #ifdef CONFIG_ALIGNMENT_TRAP
143 ldr ip, __cr_alignment
145 mcr p15, 0, ip, c1, c0 @ update control register
149 str r4, [sp, #-S_OFF]! @ push fifth arg
152 ldr ip, [tsk, #TI_FLAGS] @ check for syscall tracing
153 bic scno, scno, #0xff000000 @ mask off SWI op-code
154 eor scno, scno, #__NR_SYSCALL_BASE @ check OS number
155 adr tbl, sys_call_table @ load syscall table pointer
156 tst ip, #_TIF_SYSCALL_TRACE @ are we tracing syscalls?
159 adr lr, ret_fast_syscall @ return address
160 cmp scno, #NR_syscalls @ check upper syscall limit
161 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
164 2: mov why, #0 @ no longer a real syscall
165 cmp scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE)
166 eor r0, scno, #__NR_SYSCALL_BASE @ put OS number back
168 b sys_ni_syscall @ not private func
171 * This is the really slow path. We're going to be doing
172 * context switches, and waiting for our parent to respond.
176 mov r0, #0 @ trace entry [IP = 0]
179 adr lr, __sys_trace_return @ return address
180 add r1, sp, #S_R0 + S_OFF @ pointer to regs
181 cmp scno, #NR_syscalls @ check upper syscall limit
182 ldmccia r1, {r0 - r3} @ have to reload r0 - r3
183 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
187 str r0, [sp, #S_R0 + S_OFF]! @ save returned r0
189 mov r0, #1 @ trace exit [IP = 1]
194 #ifdef CONFIG_ALIGNMENT_TRAP
195 .type __cr_alignment, #object
200 .type sys_call_table, #object
201 ENTRY(sys_call_table)
204 /*============================================================================
205 * Special system call wrappers
207 @ r0 = syscall number
209 .type sys_syscall, #function
211 eor scno, r0, #__NR_SYSCALL_BASE
212 cmp scno, #__NR_syscall - __NR_SYSCALL_BASE
213 cmpne scno, #NR_syscalls @ check range
214 stmloia sp, {r5, r6} @ shuffle args
219 ldrlo pc, [tbl, scno, lsl #2]
239 sys_sigsuspend_wrapper:
243 sys_rt_sigsuspend_wrapper:
247 sys_sigreturn_wrapper:
251 sys_rt_sigreturn_wrapper:
255 sys_sigaltstack_wrapper:
256 ldr r2, [sp, #S_OFF + S_SP]
260 str r5, [sp, #4] @ push sixth arg
263 sys_arm_fadvise64_64_wrapper:
264 str r5, [sp, #4] @ push r5 to stack
265 b sys_arm_fadvise64_64
272 str r5, [sp, #4] @ push sixth arg
276 * Note: off_4k (r5) is always units of 4K. If we can't do the requested
277 * offset, we return EINVAL.
282 moveq r5, r5, lsr #PAGE_SHIFT - 12