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 disable_irq @ disable interrupts 52 b no_work_pending 53 54work_resched: 55 bl schedule 56/* 57 * "slow" syscall return path. "why" tells us if this was a real syscall. 58 */ 59ENTRY(ret_to_user) 60ret_slow_syscall: 61 disable_irq @ disable interrupts 62 ldr r1, [tsk, #TI_FLAGS] 63 tst r1, #_TIF_WORK_MASK 64 bne work_pending 65no_work_pending: 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 71 mov r0, r0 72 add sp, sp, #S_FRAME_SIZE - S_PC 73 movs pc, lr @ return & move spsr_svc into cpsr 74 75/* 76 * This is how we return from a fork. 77 */ 78ENTRY(ret_from_fork) 79 bl schedule_tail 80 get_thread_info tsk 81 ldr r1, [tsk, #TI_FLAGS] @ check for syscall tracing 82 mov why, #1 83 tst r1, #_TIF_SYSCALL_TRACE @ are we tracing syscalls? 84 beq ret_slow_syscall 85 mov r1, sp 86 mov r0, #1 @ trace exit [IP = 1] 87 bl syscall_trace 88 b ret_slow_syscall 89 90 91#include "calls.S" 92 93/*============================================================================= 94 * SWI handler 95 *----------------------------------------------------------------------------- 96 */ 97 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. 100 --pb */ 101#ifdef CONFIG_CPU_ARM710 102 .macro arm710_bug_check, instr, temp 103 and \temp, \instr, #0x0f000000 @ check for SWI 104 teq \temp, #0x0f000000 105 bne .Larm700bug 106 .endm 107 108.Larm700bug: 109 ldmia sp, {r0 - lr}^ @ Get calling r0 - lr 110 mov r0, r0 111 add sp, sp, #S_FRAME_SIZE 112 subs pc, lr, #4 113#else 114 .macro arm710_bug_check, instr, temp 115 .endm 116#endif 117 118 .align 5 119ENTRY(vector_swi) 120 sub sp, sp, #S_FRAME_SIZE 121 stmia sp, {r0 - r12} @ Calling r0 - r12 122 add r8, sp, #S_PC 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 128 zero_fp 129 130 /* 131 * Get the system call number. 132 */ 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] 137#else 138 ldr scno, [lr, #-4] @ get SWI instruction 139#endif 140 arm710_bug_check scno, ip 141 142#ifdef CONFIG_ALIGNMENT_TRAP 143 ldr ip, __cr_alignment 144 ldr ip, [ip] 145 mcr p15, 0, ip, c1, c0 @ update control register 146#endif 147 enable_irq 148 149 str r4, [sp, #-S_OFF]! @ push fifth arg 150 151 get_thread_info tsk 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? 157 bne __sys_trace 158 159 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 162 163 add r1, sp, #S_OFF 1642: 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 167 bcs arm_syscall 168 b sys_ni_syscall @ not private func 169 170 /* 171 * This is the really slow path. We're going to be doing 172 * context switches, and waiting for our parent to respond. 173 */ 174__sys_trace: 175 add r1, sp, #S_OFF 176 mov r0, #0 @ trace entry [IP = 0] 177 bl syscall_trace 178 179 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 184 b 2b 185 186__sys_trace_return: 187 str r0, [sp, #S_R0 + S_OFF]! @ save returned r0 188 mov r1, sp 189 mov r0, #1 @ trace exit [IP = 1] 190 bl syscall_trace 191 b ret_slow_syscall 192 193 .align 5 194#ifdef CONFIG_ALIGNMENT_TRAP 195 .type __cr_alignment, #object 196__cr_alignment: 197 .word cr_alignment 198#endif 199 200 .type sys_call_table, #object 201ENTRY(sys_call_table) 202#include "calls.S" 203 204/*============================================================================ 205 * Special system call wrappers 206 */ 207@ r0 = syscall number 208@ r5 = syscall table 209 .type sys_syscall, #function 210sys_syscall: 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 215 movlo r0, r1 216 movlo r1, r2 217 movlo r2, r3 218 movlo r3, r4 219 ldrlo pc, [tbl, scno, lsl #2] 220 b sys_ni_syscall 221 222sys_fork_wrapper: 223 add r0, sp, #S_OFF 224 b sys_fork 225 226sys_vfork_wrapper: 227 add r0, sp, #S_OFF 228 b sys_vfork 229 230sys_execve_wrapper: 231 add r3, sp, #S_OFF 232 b sys_execve 233 234sys_clone_wrapper: 235 add ip, sp, #S_OFF 236 str ip, [sp, #4] 237 b sys_clone 238 239sys_sigsuspend_wrapper: 240 add r3, sp, #S_OFF 241 b sys_sigsuspend 242 243sys_rt_sigsuspend_wrapper: 244 add r2, sp, #S_OFF 245 b sys_rt_sigsuspend 246 247sys_sigreturn_wrapper: 248 add r0, sp, #S_OFF 249 b sys_sigreturn 250 251sys_rt_sigreturn_wrapper: 252 add r0, sp, #S_OFF 253 b sys_rt_sigreturn 254 255sys_sigaltstack_wrapper: 256 ldr r2, [sp, #S_OFF + S_SP] 257 b do_sigaltstack 258 259sys_futex_wrapper: 260 str r5, [sp, #4] @ push sixth arg 261 b sys_futex 262 263sys_arm_fadvise64_64_wrapper: 264 str r5, [sp, #4] @ push r5 to stack 265 b sys_arm_fadvise64_64 266 267sys_mbind_wrapper: 268 str r5, [sp, #4] 269 b sys_mbind 270 271sys_ipc_wrapper: 272 str r5, [sp, #4] @ push sixth arg 273 b sys_ipc 274 275/* 276 * Note: off_4k (r5) is always units of 4K. If we can't do the requested 277 * offset, we return EINVAL. 278 */ 279sys_mmap2: 280#if PAGE_SHIFT > 12 281 tst r5, #PGOFF_MASK 282 moveq r5, r5, lsr #PAGE_SHIFT - 12 283 streq r5, [sp, #4] 284 beq do_mmap2 285 mov r0, #-EINVAL 286 RETINSTR(mov,pc, lr) 287#else 288 str r5, [sp, #4] 289 b do_mmap2 290#endif 291