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 .equ NR_syscalls,0 91#define CALL(x) .equ NR_syscalls,NR_syscalls+1 92#include "calls.S" 93#undef CALL 94#define CALL(x) .long x 95 96/*============================================================================= 97 * SWI handler 98 *----------------------------------------------------------------------------- 99 */ 100 101 /* If we're optimising for StrongARM the resulting code won't 102 run on an ARM7 and we can save a couple of instructions. 103 --pb */ 104#ifdef CONFIG_CPU_ARM710 105#define A710(code...) code 106.Larm710bug: 107 ldmia sp, {r0 - lr}^ @ Get calling r0 - lr 108 mov r0, r0 109 add sp, sp, #S_FRAME_SIZE 110 subs pc, lr, #4 111#else 112#define A710(code...) 113#endif 114 115 .align 5 116ENTRY(vector_swi) 117 sub sp, sp, #S_FRAME_SIZE 118 stmia sp, {r0 - r12} @ Calling r0 - r12 119 add r8, sp, #S_PC 120 stmdb r8, {sp, lr}^ @ Calling sp, lr 121 mrs r8, spsr @ called from non-FIQ mode, so ok. 122 str lr, [sp, #S_PC] @ Save calling PC 123 str r8, [sp, #S_PSR] @ Save CPSR 124 str r0, [sp, #S_OLD_R0] @ Save OLD_R0 125 zero_fp 126 127 /* 128 * Get the system call number. 129 */ 130 131#if defined(CONFIG_OABI_COMPAT) 132 133 /* 134 * If we have CONFIG_OABI_COMPAT then we need to look at the swi 135 * value to determine if it is an EABI or an old ABI call. 136 */ 137#ifdef CONFIG_ARM_THUMB 138 tst r8, #PSR_T_BIT 139 movne r10, #0 @ no thumb OABI emulation 140 ldreq r10, [lr, #-4] @ get SWI instruction 141#else 142 ldr r10, [lr, #-4] @ get SWI instruction 143 A710( and ip, r10, #0x0f000000 @ check for SWI ) 144 A710( teq ip, #0x0f000000 ) 145 A710( bne .Larm710bug ) 146#endif 147 148#elif defined(CONFIG_AEABI) 149 150 /* 151 * Pure EABI user space always put syscall number into scno (r7). 152 */ 153 A710( ldr ip, [lr, #-4] @ get SWI instruction ) 154 A710( and ip, ip, #0x0f000000 @ check for SWI ) 155 A710( teq ip, #0x0f000000 ) 156 A710( bne .Larm710bug ) 157 158#elif defined(CONFIG_ARM_THUMB) 159 160 /* Legacy ABI only, possibly thumb mode. */ 161 tst r8, #PSR_T_BIT @ this is SPSR from save_user_regs 162 addne scno, r7, #__NR_SYSCALL_BASE @ put OS number in 163 ldreq scno, [lr, #-4] 164 165#else 166 167 /* Legacy ABI only. */ 168 ldr scno, [lr, #-4] @ get SWI instruction 169 A710( and ip, scno, #0x0f000000 @ check for SWI ) 170 A710( teq ip, #0x0f000000 ) 171 A710( bne .Larm710bug ) 172 173#endif 174 175#ifdef CONFIG_ALIGNMENT_TRAP 176 ldr ip, __cr_alignment 177 ldr ip, [ip] 178 mcr p15, 0, ip, c1, c0 @ update control register 179#endif 180 enable_irq 181 182 get_thread_info tsk 183 adr tbl, sys_call_table @ load syscall table pointer 184 ldr ip, [tsk, #TI_FLAGS] @ check for syscall tracing 185 186#if defined(CONFIG_OABI_COMPAT) 187 /* 188 * If the swi argument is zero, this is an EABI call and we do nothing. 189 * 190 * If this is an old ABI call, get the syscall number into scno and 191 * get the old ABI syscall table address. 192 */ 193 bics r10, r10, #0xff000000 194 eorne scno, r10, #__NR_OABI_SYSCALL_BASE 195 ldrne tbl, =sys_oabi_call_table 196#elif !defined(CONFIG_AEABI) 197 bic scno, scno, #0xff000000 @ mask off SWI op-code 198 eor scno, scno, #__NR_SYSCALL_BASE @ check OS number 199#endif 200 201 stmdb sp!, {r4, r5} @ push fifth and sixth args 202 tst ip, #_TIF_SYSCALL_TRACE @ are we tracing syscalls? 203 bne __sys_trace 204 205 cmp scno, #NR_syscalls @ check upper syscall limit 206 adr lr, ret_fast_syscall @ return address 207 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine 208 209 add r1, sp, #S_OFF 2102: mov why, #0 @ no longer a real syscall 211 cmp scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE) 212 eor r0, scno, #__NR_SYSCALL_BASE @ put OS number back 213 bcs arm_syscall 214 b sys_ni_syscall @ not private func 215 216 /* 217 * This is the really slow path. We're going to be doing 218 * context switches, and waiting for our parent to respond. 219 */ 220__sys_trace: 221 mov r2, scno 222 add r1, sp, #S_OFF 223 mov r0, #0 @ trace entry [IP = 0] 224 bl syscall_trace 225 226 adr lr, __sys_trace_return @ return address 227 mov scno, r0 @ syscall number (possibly new) 228 add r1, sp, #S_R0 + S_OFF @ pointer to regs 229 cmp scno, #NR_syscalls @ check upper syscall limit 230 ldmccia r1, {r0 - r3} @ have to reload r0 - r3 231 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine 232 b 2b 233 234__sys_trace_return: 235 str r0, [sp, #S_R0 + S_OFF]! @ save returned r0 236 mov r2, scno 237 mov r1, sp 238 mov r0, #1 @ trace exit [IP = 1] 239 bl syscall_trace 240 b ret_slow_syscall 241 242 .align 5 243#ifdef CONFIG_ALIGNMENT_TRAP 244 .type __cr_alignment, #object 245__cr_alignment: 246 .word cr_alignment 247#endif 248 .ltorg 249 250/* 251 * This is the syscall table declaration for native ABI syscalls. 252 * With EABI a couple syscalls are obsolete and defined as sys_ni_syscall. 253 */ 254#define ABI(native, compat) native 255#ifdef CONFIG_AEABI 256#define OBSOLETE(syscall) sys_ni_syscall 257#else 258#define OBSOLETE(syscall) syscall 259#endif 260 261 .type sys_call_table, #object 262ENTRY(sys_call_table) 263#include "calls.S" 264#undef ABI 265#undef OBSOLETE 266 267/*============================================================================ 268 * Special system call wrappers 269 */ 270@ r0 = syscall number 271@ r8 = syscall table 272 .type sys_syscall, #function 273sys_syscall: 274 eor scno, r0, #__NR_OABI_SYSCALL_BASE 275 cmp scno, #__NR_syscall - __NR_SYSCALL_BASE 276 cmpne scno, #NR_syscalls @ check range 277 stmloia sp, {r5, r6} @ shuffle args 278 movlo r0, r1 279 movlo r1, r2 280 movlo r2, r3 281 movlo r3, r4 282 ldrlo pc, [tbl, scno, lsl #2] 283 b sys_ni_syscall 284 285sys_fork_wrapper: 286 add r0, sp, #S_OFF 287 b sys_fork 288 289sys_vfork_wrapper: 290 add r0, sp, #S_OFF 291 b sys_vfork 292 293sys_execve_wrapper: 294 add r3, sp, #S_OFF 295 b sys_execve 296 297sys_clone_wrapper: 298 add ip, sp, #S_OFF 299 str ip, [sp, #4] 300 b sys_clone 301 302sys_sigsuspend_wrapper: 303 add r3, sp, #S_OFF 304 b sys_sigsuspend 305 306sys_rt_sigsuspend_wrapper: 307 add r2, sp, #S_OFF 308 b sys_rt_sigsuspend 309 310sys_sigreturn_wrapper: 311 add r0, sp, #S_OFF 312 b sys_sigreturn 313 314sys_rt_sigreturn_wrapper: 315 add r0, sp, #S_OFF 316 b sys_rt_sigreturn 317 318sys_sigaltstack_wrapper: 319 ldr r2, [sp, #S_OFF + S_SP] 320 b do_sigaltstack 321 322sys_statfs64_wrapper: 323 teq r1, #88 324 moveq r1, #84 325 b sys_statfs64 326 327sys_fstatfs64_wrapper: 328 teq r1, #88 329 moveq r1, #84 330 b sys_fstatfs64 331 332/* 333 * Note: off_4k (r5) is always units of 4K. If we can't do the requested 334 * offset, we return EINVAL. 335 */ 336sys_mmap2: 337#if PAGE_SHIFT > 12 338 tst r5, #PGOFF_MASK 339 moveq r5, r5, lsr #PAGE_SHIFT - 12 340 streq r5, [sp, #4] 341 beq do_mmap2 342 mov r0, #-EINVAL 343 RETINSTR(mov,pc, lr) 344#else 345 str r5, [sp, #4] 346 b do_mmap2 347#endif 348 349#ifdef CONFIG_OABI_COMPAT 350 351/* 352 * These are syscalls with argument register differences 353 */ 354 355sys_oabi_pread64: 356 stmia sp, {r3, r4} 357 b sys_pread64 358 359sys_oabi_pwrite64: 360 stmia sp, {r3, r4} 361 b sys_pwrite64 362 363sys_oabi_truncate64: 364 mov r3, r2 365 mov r2, r1 366 b sys_truncate64 367 368sys_oabi_ftruncate64: 369 mov r3, r2 370 mov r2, r1 371 b sys_ftruncate64 372 373sys_oabi_readahead: 374 str r3, [sp] 375 mov r3, r2 376 mov r2, r1 377 b sys_readahead 378 379/* 380 * Let's declare a second syscall table for old ABI binaries 381 * using the compatibility syscall entries. 382 */ 383#define ABI(native, compat) compat 384#define OBSOLETE(syscall) syscall 385 386 .type sys_oabi_call_table, #object 387ENTRY(sys_oabi_call_table) 388#include "calls.S" 389#undef ABI 390#undef OBSOLETE 391 392#endif 393 394