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/thread_info.h>
13 #include <asm/ptrace.h>
14 #include <asm/unistd.h>
16 #include "entry-header.S"
21 * This is the fast syscall return path. We do as little as
22 * possible here, and this includes saving r0 back into the SVC
26 disable_irq @ disable interrupts
27 ldr r1, [tsk, #TI_FLAGS]
28 tst r1, #_TIF_WORK_MASK
30 fast_restore_user_regs
33 * Ok, we need to do extra processing, enter the slow path.
36 str r0, [sp, #S_R0+S_OFF]! @ returned r0
38 tst r1, #_TIF_NEED_RESCHED
40 tst r1, #_TIF_NOTIFY_RESUME | _TIF_SIGPENDING
43 mov r2, why @ 'syscall'
45 disable_irq @ disable interrupts
51 * "slow" syscall return path. "why" tells us if this was a real syscall.
55 disable_irq @ disable interrupts
56 ldr r1, [tsk, #TI_FLAGS]
57 tst r1, #_TIF_WORK_MASK
60 slow_restore_user_regs
63 * This is how we return from a fork.
68 ldr r1, [tsk, #TI_FLAGS] @ check for syscall tracing
70 tst r1, #_TIF_SYSCALL_TRACE @ are we tracing syscalls?
73 mov r0, #1 @ trace exit [IP = 1]
80 /*=============================================================================
82 *-----------------------------------------------------------------------------
85 /* If we're optimising for StrongARM the resulting code won't
86 run on an ARM7 and we can save a couple of instructions.
88 #ifdef CONFIG_CPU_ARM710
89 .macro arm710_bug_check, instr, temp
90 and \temp, \instr, #0x0f000000 @ check for SWI
91 teq \temp, #0x0f000000
96 ldr r0, [sp, #S_PSR] @ Get calling cpsr
100 ldmia sp, {r0 - lr}^ @ Get calling r0 - lr
102 ldr lr, [sp, #S_PC] @ Get PC
103 add sp, sp, #S_FRAME_SIZE
106 .macro arm710_bug_check, instr, temp
115 arm710_bug_check scno, ip
117 #ifdef CONFIG_ALIGNMENT_TRAP
118 ldr ip, __cr_alignment
120 mcr p15, 0, ip, c1, c0 @ update control register
124 str r4, [sp, #-S_OFF]! @ push fifth arg
127 ldr ip, [tsk, #TI_FLAGS] @ check for syscall tracing
128 bic scno, scno, #0xff000000 @ mask off SWI op-code
129 eor scno, scno, #OS_NUMBER << 20 @ check OS number
130 adr tbl, sys_call_table @ load syscall table pointer
131 tst ip, #_TIF_SYSCALL_TRACE @ are we tracing syscalls?
134 adr lr, ret_fast_syscall @ return address
135 cmp scno, #NR_syscalls @ check upper syscall limit
136 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
139 2: mov why, #0 @ no longer a real syscall
140 cmp scno, #ARMSWI_OFFSET
141 eor r0, scno, #OS_NUMBER << 20 @ put OS number back
143 b sys_ni_syscall @ not private func
146 * This is the really slow path. We're going to be doing
147 * context switches, and waiting for our parent to respond.
151 mov r0, #0 @ trace entry [IP = 0]
154 adr lr, __sys_trace_return @ return address
155 add r1, sp, #S_R0 + S_OFF @ pointer to regs
156 cmp scno, #NR_syscalls @ check upper syscall limit
157 ldmccia r1, {r0 - r3} @ have to reload r0 - r3
158 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
162 str r0, [sp, #S_R0 + S_OFF]! @ save returned r0
164 mov r0, #1 @ trace exit [IP = 1]
169 #ifdef CONFIG_ALIGNMENT_TRAP
170 .type __cr_alignment, #object
175 .type sys_call_table, #object
176 ENTRY(sys_call_table)
179 /*============================================================================
180 * Special system call wrappers
182 @ r0 = syscall number
184 .type sys_syscall, #function
186 eor scno, r0, #OS_NUMBER << 20
187 cmp scno, #__NR_syscall - __NR_SYSCALL_BASE
188 cmpne scno, #NR_syscalls @ check range
189 stmloia sp, {r5, r6} @ shuffle args
194 ldrlo pc, [tbl, scno, lsl #2]
214 sys_sigsuspend_wrapper:
218 sys_rt_sigsuspend_wrapper:
222 sys_sigreturn_wrapper:
226 sys_rt_sigreturn_wrapper:
230 sys_sigaltstack_wrapper:
231 ldr r2, [sp, #S_OFF + S_SP]
235 str r5, [sp, #4] @ push sixth arg
239 * Note: off_4k (r5) is always units of 4K. If we can't do the requested
240 * offset, we return EINVAL.
245 moveq r5, r5, lsr #PAGE_SHIFT - 12