1/* 2 * linux/arch/arm/kernel/entry-common.S 3 * 4 * Copyright (C) 2000 Russell King 5 * 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. 9 */ 10#include <linux/config.h> 11 12#include <asm/unistd.h> 13 14#include "entry-header.S" 15 16 17 .align 5 18/* 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 21 * stack. 22 */ 23ret_fast_syscall: 24 disable_irq @ disable interrupts 25 ldr r1, [tsk, #TI_FLAGS] 26 tst r1, #_TIF_WORK_MASK 27 bne fast_work_pending 28 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 34 mov r0, r0 35 add sp, sp, #S_FRAME_SIZE - S_PC 36 movs pc, lr @ return & move spsr_svc into cpsr 37 38/* 39 * Ok, we need to do extra processing, enter the slow path. 40 */ 41fast_work_pending: 42 str r0, [sp, #S_R0+S_OFF]! @ returned r0 43work_pending: 44 tst r1, #_TIF_NEED_RESCHED 45 bne work_resched 46 tst r1, #_TIF_NOTIFY_RESUME | _TIF_SIGPENDING 47 beq no_work_pending 48 mov r0, sp @ 'regs' 49 mov r2, why @ 'syscall' 50 bl do_notify_resume 51 b ret_slow_syscall @ Check work again 52 53work_resched: 54 bl schedule 55/* 56 * "slow" syscall return path. "why" tells us if this was a real syscall. 57 */ 58ENTRY(ret_to_user) 59ret_slow_syscall: 60 disable_irq @ disable interrupts 61 ldr r1, [tsk, #TI_FLAGS] 62 tst r1, #_TIF_WORK_MASK 63 bne work_pending 64no_work_pending: 65 @ slow_restore_user_regs 66 ldr r1, [sp, #S_PSR] @ get calling cpsr 67 ldr lr, [sp, #S_PC]! @ get pc 68 msr spsr_cxsf, r1 @ save in spsr_svc 69 ldmdb sp, {r0 - lr}^ @ get calling r1 - lr 70 mov r0, r0 71 add sp, sp, #S_FRAME_SIZE - S_PC 72 movs pc, lr @ return & move spsr_svc into cpsr 73 74/* 75 * This is how we return from a fork. 76 */ 77ENTRY(ret_from_fork) 78 bl schedule_tail 79 get_thread_info tsk 80 ldr r1, [tsk, #TI_FLAGS] @ check for syscall tracing 81 mov why, #1 82 tst r1, #_TIF_SYSCALL_TRACE @ are we tracing syscalls? 83 beq ret_slow_syscall 84 mov r1, sp 85 mov r0, #1 @ trace exit [IP = 1] 86 bl syscall_trace 87 b ret_slow_syscall 88 89 90#include "calls.S" 91 92/*============================================================================= 93 * SWI handler 94 *----------------------------------------------------------------------------- 95 */ 96 97 /* If we're optimising for StrongARM the resulting code won't 98 run on an ARM7 and we can save a couple of instructions. 99 --pb */ 100#ifdef CONFIG_CPU_ARM710 101 .macro arm710_bug_check, instr, temp 102 and \temp, \instr, #0x0f000000 @ check for SWI 103 teq \temp, #0x0f000000 104 bne .Larm700bug 105 .endm 106 107.Larm700bug: 108 ldmia sp, {r0 - lr}^ @ Get calling r0 - lr 109 mov r0, r0 110 add sp, sp, #S_FRAME_SIZE 111 subs pc, lr, #4 112#else 113 .macro arm710_bug_check, instr, temp 114 .endm 115#endif 116 117 .align 5 118ENTRY(vector_swi) 119 sub sp, sp, #S_FRAME_SIZE 120 stmia sp, {r0 - r12} @ Calling r0 - r12 121 add r8, sp, #S_PC 122 stmdb r8, {sp, lr}^ @ Calling sp, lr 123 mrs r8, spsr @ called from non-FIQ mode, so ok. 124 str lr, [sp, #S_PC] @ Save calling PC 125 str r8, [sp, #S_PSR] @ Save CPSR 126 str r0, [sp, #S_OLD_R0] @ Save OLD_R0 127 zero_fp 128 129 /* 130 * Get the system call number. 131 */ 132#ifdef CONFIG_ARM_THUMB 133 tst r8, #PSR_T_BIT @ this is SPSR from save_user_regs 134 addne scno, r7, #__NR_SYSCALL_BASE @ put OS number in 135 ldreq scno, [lr, #-4] 136#else 137 ldr scno, [lr, #-4] @ get SWI instruction 138#endif 139 arm710_bug_check scno, ip 140 141#ifdef CONFIG_ALIGNMENT_TRAP 142 ldr ip, __cr_alignment 143 ldr ip, [ip] 144 mcr p15, 0, ip, c1, c0 @ update control register 145#endif 146 enable_irq 147 148 str r4, [sp, #-S_OFF]! @ push fifth arg 149 150 get_thread_info tsk 151 ldr ip, [tsk, #TI_FLAGS] @ check for syscall tracing 152 bic scno, scno, #0xff000000 @ mask off SWI op-code 153 eor scno, scno, #__NR_SYSCALL_BASE @ check OS number 154 adr tbl, sys_call_table @ load syscall table pointer 155 tst ip, #_TIF_SYSCALL_TRACE @ are we tracing syscalls? 156 bne __sys_trace 157 158 adr lr, ret_fast_syscall @ return address 159 cmp scno, #NR_syscalls @ check upper syscall limit 160 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine 161 162 add r1, sp, #S_OFF 1632: mov why, #0 @ no longer a real syscall 164 cmp scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE) 165 eor r0, scno, #__NR_SYSCALL_BASE @ put OS number back 166 bcs arm_syscall 167 b sys_ni_syscall @ not private func 168 169 /* 170 * This is the really slow path. We're going to be doing 171 * context switches, and waiting for our parent to respond. 172 */ 173__sys_trace: 174 add r1, sp, #S_OFF 175 mov r0, #0 @ trace entry [IP = 0] 176 bl syscall_trace 177 178 adr lr, __sys_trace_return @ return address 179 add r1, sp, #S_R0 + S_OFF @ pointer to regs 180 cmp scno, #NR_syscalls @ check upper syscall limit 181 ldmccia r1, {r0 - r3} @ have to reload r0 - r3 182 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine 183 b 2b 184 185__sys_trace_return: 186 str r0, [sp, #S_R0 + S_OFF]! @ save returned r0 187 mov r1, sp 188 mov r0, #1 @ trace exit [IP = 1] 189 bl syscall_trace 190 b ret_slow_syscall 191 192 .align 5 193#ifdef CONFIG_ALIGNMENT_TRAP 194 .type __cr_alignment, #object 195__cr_alignment: 196 .word cr_alignment 197#endif 198 199 .type sys_call_table, #object 200ENTRY(sys_call_table) 201#include "calls.S" 202 203/*============================================================================ 204 * Special system call wrappers 205 */ 206@ r0 = syscall number 207@ r5 = syscall table 208 .type sys_syscall, #function 209sys_syscall: 210 eor scno, r0, #__NR_SYSCALL_BASE 211 cmp scno, #__NR_syscall - __NR_SYSCALL_BASE 212 cmpne scno, #NR_syscalls @ check range 213 stmloia sp, {r5, r6} @ shuffle args 214 movlo r0, r1 215 movlo r1, r2 216 movlo r2, r3 217 movlo r3, r4 218 ldrlo pc, [tbl, scno, lsl #2] 219 b sys_ni_syscall 220 221sys_fork_wrapper: 222 add r0, sp, #S_OFF 223 b sys_fork 224 225sys_vfork_wrapper: 226 add r0, sp, #S_OFF 227 b sys_vfork 228 229sys_execve_wrapper: 230 add r3, sp, #S_OFF 231 b sys_execve 232 233sys_clone_wrapper: 234 add ip, sp, #S_OFF 235 str ip, [sp, #4] 236 b sys_clone 237 238sys_sigsuspend_wrapper: 239 add r3, sp, #S_OFF 240 b sys_sigsuspend 241 242sys_rt_sigsuspend_wrapper: 243 add r2, sp, #S_OFF 244 b sys_rt_sigsuspend 245 246sys_sigreturn_wrapper: 247 add r0, sp, #S_OFF 248 b sys_sigreturn 249 250sys_rt_sigreturn_wrapper: 251 add r0, sp, #S_OFF 252 b sys_rt_sigreturn 253 254sys_sigaltstack_wrapper: 255 ldr r2, [sp, #S_OFF + S_SP] 256 b do_sigaltstack 257 258sys_futex_wrapper: 259 str r5, [sp, #4] @ push sixth arg 260 b sys_futex 261 262sys_arm_fadvise64_64_wrapper: 263 str r5, [sp, #4] @ push r5 to stack 264 b sys_arm_fadvise64_64 265 266sys_mbind_wrapper: 267 str r5, [sp, #4] 268 b sys_mbind 269 270sys_ipc_wrapper: 271 str r5, [sp, #4] @ push sixth arg 272 b sys_ipc 273 274/* 275 * Note: off_4k (r5) is always units of 4K. If we can't do the requested 276 * offset, we return EINVAL. 277 */ 278sys_mmap2: 279#if PAGE_SHIFT > 12 280 tst r5, #PGOFF_MASK 281 moveq r5, r5, lsr #PAGE_SHIFT - 12 282 streq r5, [sp, #4] 283 beq do_mmap2 284 mov r0, #-EINVAL 285 RETINSTR(mov,pc, lr) 286#else 287 str r5, [sp, #4] 288 b do_mmap2 289#endif 290