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 11#include <asm/unistd.h> 12#include <asm/ftrace.h> 13#include <mach/entry-macro.S> 14#include <asm/unwind.h> 15 16#include "entry-header.S" 17 18 19 .align 5 20/* 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 23 * stack. 24 */ 25ret_fast_syscall: 26 UNWIND(.fnstart ) 27 UNWIND(.cantunwind ) 28 disable_irq @ disable interrupts 29 ldr r1, [tsk, #TI_FLAGS] 30 tst r1, #_TIF_WORK_MASK 31 bne fast_work_pending 32 33 /* perform architecture specific actions before user return */ 34 arch_ret_to_user r1, lr 35 36 @ fast_restore_user_regs 37 ldr r1, [sp, #S_OFF + S_PSR] @ get calling cpsr 38 ldr lr, [sp, #S_OFF + S_PC]! @ get pc 39 msr spsr_cxsf, r1 @ save in spsr_svc 40 ldmdb sp, {r1 - lr}^ @ get calling r1 - lr 41 mov r0, r0 42 add sp, sp, #S_FRAME_SIZE - S_PC 43 movs pc, lr @ return & move spsr_svc into cpsr 44 UNWIND(.fnend ) 45 46/* 47 * Ok, we need to do extra processing, enter the slow path. 48 */ 49fast_work_pending: 50 str r0, [sp, #S_R0+S_OFF]! @ returned r0 51work_pending: 52 tst r1, #_TIF_NEED_RESCHED 53 bne work_resched 54 tst r1, #_TIF_SIGPENDING 55 beq no_work_pending 56 mov r0, sp @ 'regs' 57 mov r2, why @ 'syscall' 58 bl do_notify_resume 59 b ret_slow_syscall @ Check work again 60 61work_resched: 62 bl schedule 63/* 64 * "slow" syscall return path. "why" tells us if this was a real syscall. 65 */ 66ENTRY(ret_to_user) 67ret_slow_syscall: 68 disable_irq @ disable interrupts 69 ldr r1, [tsk, #TI_FLAGS] 70 tst r1, #_TIF_WORK_MASK 71 bne work_pending 72no_work_pending: 73 /* perform architecture specific actions before user return */ 74 arch_ret_to_user r1, lr 75 76 @ slow_restore_user_regs 77 ldr r1, [sp, #S_PSR] @ get calling cpsr 78 ldr lr, [sp, #S_PC]! @ get pc 79 msr spsr_cxsf, r1 @ save in spsr_svc 80 ldmdb sp, {r0 - lr}^ @ get calling r0 - lr 81 mov r0, r0 82 add sp, sp, #S_FRAME_SIZE - S_PC 83 movs pc, lr @ return & move spsr_svc into cpsr 84ENDPROC(ret_to_user) 85 86/* 87 * This is how we return from a fork. 88 */ 89ENTRY(ret_from_fork) 90 bl schedule_tail 91 get_thread_info tsk 92 ldr r1, [tsk, #TI_FLAGS] @ check for syscall tracing 93 mov why, #1 94 tst r1, #_TIF_SYSCALL_TRACE @ are we tracing syscalls? 95 beq ret_slow_syscall 96 mov r1, sp 97 mov r0, #1 @ trace exit [IP = 1] 98 bl syscall_trace 99 b ret_slow_syscall 100ENDPROC(ret_from_fork) 101 102 .equ NR_syscalls,0 103#define CALL(x) .equ NR_syscalls,NR_syscalls+1 104#include "calls.S" 105#undef CALL 106#define CALL(x) .long x 107 108#ifdef CONFIG_FUNCTION_TRACER 109#ifdef CONFIG_DYNAMIC_FTRACE 110ENTRY(mcount) 111 stmdb sp!, {r0-r3, lr} 112 mov r0, lr 113 sub r0, r0, #MCOUNT_INSN_SIZE 114 115 .globl mcount_call 116mcount_call: 117 bl ftrace_stub 118 ldr lr, [fp, #-4] @ restore lr 119 ldmia sp!, {r0-r3, pc} 120 121ENTRY(ftrace_caller) 122 stmdb sp!, {r0-r3, lr} 123 ldr r1, [fp, #-4] 124 mov r0, lr 125 sub r0, r0, #MCOUNT_INSN_SIZE 126 127 .globl ftrace_call 128ftrace_call: 129 bl ftrace_stub 130 ldr lr, [fp, #-4] @ restore lr 131 ldmia sp!, {r0-r3, pc} 132 133#else 134 135ENTRY(mcount) 136 stmdb sp!, {r0-r3, lr} 137 ldr r0, =ftrace_trace_function 138 ldr r2, [r0] 139 adr r0, ftrace_stub 140 cmp r0, r2 141 bne trace 142 ldr lr, [fp, #-4] @ restore lr 143 ldmia sp!, {r0-r3, pc} 144 145trace: 146 ldr r1, [fp, #-4] @ lr of instrumented routine 147 mov r0, lr 148 sub r0, r0, #MCOUNT_INSN_SIZE 149 mov lr, pc 150 mov pc, r2 151 mov lr, r1 @ restore lr 152 ldmia sp!, {r0-r3, pc} 153 154#endif /* CONFIG_DYNAMIC_FTRACE */ 155 156 .globl ftrace_stub 157ftrace_stub: 158 mov pc, lr 159 160#endif /* CONFIG_FUNCTION_TRACER */ 161 162/*============================================================================= 163 * SWI handler 164 *----------------------------------------------------------------------------- 165 */ 166 167 /* If we're optimising for StrongARM the resulting code won't 168 run on an ARM7 and we can save a couple of instructions. 169 --pb */ 170#ifdef CONFIG_CPU_ARM710 171#define A710(code...) code 172.Larm710bug: 173 ldmia sp, {r0 - lr}^ @ Get calling r0 - lr 174 mov r0, r0 175 add sp, sp, #S_FRAME_SIZE 176 subs pc, lr, #4 177#else 178#define A710(code...) 179#endif 180 181 .align 5 182ENTRY(vector_swi) 183 sub sp, sp, #S_FRAME_SIZE 184 stmia sp, {r0 - r12} @ Calling r0 - r12 185 add r8, sp, #S_PC 186 stmdb r8, {sp, lr}^ @ Calling sp, lr 187 mrs r8, spsr @ called from non-FIQ mode, so ok. 188 str lr, [sp, #S_PC] @ Save calling PC 189 str r8, [sp, #S_PSR] @ Save CPSR 190 str r0, [sp, #S_OLD_R0] @ Save OLD_R0 191 zero_fp 192 193 /* 194 * Get the system call number. 195 */ 196 197#if defined(CONFIG_OABI_COMPAT) 198 199 /* 200 * If we have CONFIG_OABI_COMPAT then we need to look at the swi 201 * value to determine if it is an EABI or an old ABI call. 202 */ 203#ifdef CONFIG_ARM_THUMB 204 tst r8, #PSR_T_BIT 205 movne r10, #0 @ no thumb OABI emulation 206 ldreq r10, [lr, #-4] @ get SWI instruction 207#else 208 ldr r10, [lr, #-4] @ get SWI instruction 209 A710( and ip, r10, #0x0f000000 @ check for SWI ) 210 A710( teq ip, #0x0f000000 ) 211 A710( bne .Larm710bug ) 212#endif 213 214#elif defined(CONFIG_AEABI) 215 216 /* 217 * Pure EABI user space always put syscall number into scno (r7). 218 */ 219 A710( ldr ip, [lr, #-4] @ get SWI instruction ) 220 A710( and ip, ip, #0x0f000000 @ check for SWI ) 221 A710( teq ip, #0x0f000000 ) 222 A710( bne .Larm710bug ) 223 224#elif defined(CONFIG_ARM_THUMB) 225 226 /* Legacy ABI only, possibly thumb mode. */ 227 tst r8, #PSR_T_BIT @ this is SPSR from save_user_regs 228 addne scno, r7, #__NR_SYSCALL_BASE @ put OS number in 229 ldreq scno, [lr, #-4] 230 231#else 232 233 /* Legacy ABI only. */ 234 ldr scno, [lr, #-4] @ get SWI instruction 235 A710( and ip, scno, #0x0f000000 @ check for SWI ) 236 A710( teq ip, #0x0f000000 ) 237 A710( bne .Larm710bug ) 238 239#endif 240 241#ifdef CONFIG_ALIGNMENT_TRAP 242 ldr ip, __cr_alignment 243 ldr ip, [ip] 244 mcr p15, 0, ip, c1, c0 @ update control register 245#endif 246 enable_irq 247 248 get_thread_info tsk 249 adr tbl, sys_call_table @ load syscall table pointer 250 ldr ip, [tsk, #TI_FLAGS] @ check for syscall tracing 251 252#if defined(CONFIG_OABI_COMPAT) 253 /* 254 * If the swi argument is zero, this is an EABI call and we do nothing. 255 * 256 * If this is an old ABI call, get the syscall number into scno and 257 * get the old ABI syscall table address. 258 */ 259 bics r10, r10, #0xff000000 260 eorne scno, r10, #__NR_OABI_SYSCALL_BASE 261 ldrne tbl, =sys_oabi_call_table 262#elif !defined(CONFIG_AEABI) 263 bic scno, scno, #0xff000000 @ mask off SWI op-code 264 eor scno, scno, #__NR_SYSCALL_BASE @ check OS number 265#endif 266 267 stmdb sp!, {r4, r5} @ push fifth and sixth args 268 tst ip, #_TIF_SYSCALL_TRACE @ are we tracing syscalls? 269 bne __sys_trace 270 271 cmp scno, #NR_syscalls @ check upper syscall limit 272 adr lr, ret_fast_syscall @ return address 273 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine 274 275 add r1, sp, #S_OFF 2762: mov why, #0 @ no longer a real syscall 277 cmp scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE) 278 eor r0, scno, #__NR_SYSCALL_BASE @ put OS number back 279 bcs arm_syscall 280 b sys_ni_syscall @ not private func 281ENDPROC(vector_swi) 282 283 /* 284 * This is the really slow path. We're going to be doing 285 * context switches, and waiting for our parent to respond. 286 */ 287__sys_trace: 288 mov r2, scno 289 add r1, sp, #S_OFF 290 mov r0, #0 @ trace entry [IP = 0] 291 bl syscall_trace 292 293 adr lr, __sys_trace_return @ return address 294 mov scno, r0 @ syscall number (possibly new) 295 add r1, sp, #S_R0 + S_OFF @ pointer to regs 296 cmp scno, #NR_syscalls @ check upper syscall limit 297 ldmccia r1, {r0 - r3} @ have to reload r0 - r3 298 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine 299 b 2b 300 301__sys_trace_return: 302 str r0, [sp, #S_R0 + S_OFF]! @ save returned r0 303 mov r2, scno 304 mov r1, sp 305 mov r0, #1 @ trace exit [IP = 1] 306 bl syscall_trace 307 b ret_slow_syscall 308 309 .align 5 310#ifdef CONFIG_ALIGNMENT_TRAP 311 .type __cr_alignment, #object 312__cr_alignment: 313 .word cr_alignment 314#endif 315 .ltorg 316 317/* 318 * This is the syscall table declaration for native ABI syscalls. 319 * With EABI a couple syscalls are obsolete and defined as sys_ni_syscall. 320 */ 321#define ABI(native, compat) native 322#ifdef CONFIG_AEABI 323#define OBSOLETE(syscall) sys_ni_syscall 324#else 325#define OBSOLETE(syscall) syscall 326#endif 327 328 .type sys_call_table, #object 329ENTRY(sys_call_table) 330#include "calls.S" 331#undef ABI 332#undef OBSOLETE 333 334/*============================================================================ 335 * Special system call wrappers 336 */ 337@ r0 = syscall number 338@ r8 = syscall table 339sys_syscall: 340 bic scno, r0, #__NR_OABI_SYSCALL_BASE 341 cmp scno, #__NR_syscall - __NR_SYSCALL_BASE 342 cmpne scno, #NR_syscalls @ check range 343 stmloia sp, {r5, r6} @ shuffle args 344 movlo r0, r1 345 movlo r1, r2 346 movlo r2, r3 347 movlo r3, r4 348 ldrlo pc, [tbl, scno, lsl #2] 349 b sys_ni_syscall 350ENDPROC(sys_syscall) 351 352sys_fork_wrapper: 353 add r0, sp, #S_OFF 354 b sys_fork 355ENDPROC(sys_fork_wrapper) 356 357sys_vfork_wrapper: 358 add r0, sp, #S_OFF 359 b sys_vfork 360ENDPROC(sys_vfork_wrapper) 361 362sys_execve_wrapper: 363 add r3, sp, #S_OFF 364 b sys_execve 365ENDPROC(sys_execve_wrapper) 366 367sys_clone_wrapper: 368 add ip, sp, #S_OFF 369 str ip, [sp, #4] 370 b sys_clone 371ENDPROC(sys_clone_wrapper) 372 373sys_sigsuspend_wrapper: 374 add r3, sp, #S_OFF 375 b sys_sigsuspend 376ENDPROC(sys_sigsuspend_wrapper) 377 378sys_rt_sigsuspend_wrapper: 379 add r2, sp, #S_OFF 380 b sys_rt_sigsuspend 381ENDPROC(sys_rt_sigsuspend_wrapper) 382 383sys_sigreturn_wrapper: 384 add r0, sp, #S_OFF 385 b sys_sigreturn 386ENDPROC(sys_sigreturn_wrapper) 387 388sys_rt_sigreturn_wrapper: 389 add r0, sp, #S_OFF 390 b sys_rt_sigreturn 391ENDPROC(sys_rt_sigreturn_wrapper) 392 393sys_sigaltstack_wrapper: 394 ldr r2, [sp, #S_OFF + S_SP] 395 b do_sigaltstack 396ENDPROC(sys_sigaltstack_wrapper) 397 398sys_statfs64_wrapper: 399 teq r1, #88 400 moveq r1, #84 401 b sys_statfs64 402ENDPROC(sys_statfs64_wrapper) 403 404sys_fstatfs64_wrapper: 405 teq r1, #88 406 moveq r1, #84 407 b sys_fstatfs64 408ENDPROC(sys_fstatfs64_wrapper) 409 410/* 411 * Note: off_4k (r5) is always units of 4K. If we can't do the requested 412 * offset, we return EINVAL. 413 */ 414sys_mmap2: 415#if PAGE_SHIFT > 12 416 tst r5, #PGOFF_MASK 417 moveq r5, r5, lsr #PAGE_SHIFT - 12 418 streq r5, [sp, #4] 419 beq do_mmap2 420 mov r0, #-EINVAL 421 mov pc, lr 422#else 423 str r5, [sp, #4] 424 b do_mmap2 425#endif 426ENDPROC(sys_mmap2) 427 428ENTRY(pabort_ifar) 429 mrc p15, 0, r0, cr6, cr0, 2 430ENTRY(pabort_noifar) 431 mov pc, lr 432ENDPROC(pabort_ifar) 433ENDPROC(pabort_noifar) 434 435#ifdef CONFIG_OABI_COMPAT 436 437/* 438 * These are syscalls with argument register differences 439 */ 440 441sys_oabi_pread64: 442 stmia sp, {r3, r4} 443 b sys_pread64 444ENDPROC(sys_oabi_pread64) 445 446sys_oabi_pwrite64: 447 stmia sp, {r3, r4} 448 b sys_pwrite64 449ENDPROC(sys_oabi_pwrite64) 450 451sys_oabi_truncate64: 452 mov r3, r2 453 mov r2, r1 454 b sys_truncate64 455ENDPROC(sys_oabi_truncate64) 456 457sys_oabi_ftruncate64: 458 mov r3, r2 459 mov r2, r1 460 b sys_ftruncate64 461ENDPROC(sys_oabi_ftruncate64) 462 463sys_oabi_readahead: 464 str r3, [sp] 465 mov r3, r2 466 mov r2, r1 467 b sys_readahead 468ENDPROC(sys_oabi_readahead) 469 470/* 471 * Let's declare a second syscall table for old ABI binaries 472 * using the compatibility syscall entries. 473 */ 474#define ABI(native, compat) compat 475#define OBSOLETE(syscall) syscall 476 477 .type sys_oabi_call_table, #object 478ENTRY(sys_oabi_call_table) 479#include "calls.S" 480#undef ABI 481#undef OBSOLETE 482 483#endif 484 485