/* * linux/arch/arm/kernel/entry-common.S * * Copyright (C) 2000 Russell King * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include <asm/unistd.h> #include "entry-header.S" .align 5 /* * This is the fast syscall return path. We do as little as * possible here, and this includes saving r0 back into the SVC * stack. */ ret_fast_syscall: disable_irq @ disable interrupts ldr r1, [tsk, #TI_FLAGS] tst r1, #_TIF_WORK_MASK bne fast_work_pending @ fast_restore_user_regs ldr r1, [sp, #S_OFF + S_PSR] @ get calling cpsr ldr lr, [sp, #S_OFF + S_PC]! @ get pc msr spsr_cxsf, r1 @ save in spsr_svc ldmdb sp, {r1 - lr}^ @ get calling r1 - lr mov r0, r0 add sp, sp, #S_FRAME_SIZE - S_PC movs pc, lr @ return & move spsr_svc into cpsr /* * Ok, we need to do extra processing, enter the slow path. */ fast_work_pending: str r0, [sp, #S_R0+S_OFF]! @ returned r0 work_pending: tst r1, #_TIF_NEED_RESCHED bne work_resched tst r1, #_TIF_NOTIFY_RESUME | _TIF_SIGPENDING beq no_work_pending mov r0, sp @ 'regs' mov r2, why @ 'syscall' bl do_notify_resume b ret_slow_syscall @ Check work again work_resched: bl schedule /* * "slow" syscall return path. "why" tells us if this was a real syscall. */ ENTRY(ret_to_user) ret_slow_syscall: disable_irq @ disable interrupts ldr r1, [tsk, #TI_FLAGS] tst r1, #_TIF_WORK_MASK bne work_pending no_work_pending: @ slow_restore_user_regs ldr r1, [sp, #S_PSR] @ get calling cpsr ldr lr, [sp, #S_PC]! @ get pc msr spsr_cxsf, r1 @ save in spsr_svc ldmdb sp, {r0 - lr}^ @ get calling r1 - lr mov r0, r0 add sp, sp, #S_FRAME_SIZE - S_PC movs pc, lr @ return & move spsr_svc into cpsr /* * This is how we return from a fork. */ ENTRY(ret_from_fork) bl schedule_tail get_thread_info tsk ldr r1, [tsk, #TI_FLAGS] @ check for syscall tracing mov why, #1 tst r1, #_TIF_SYSCALL_TRACE @ are we tracing syscalls? beq ret_slow_syscall mov r1, sp mov r0, #1 @ trace exit [IP = 1] bl syscall_trace b ret_slow_syscall .equ NR_syscalls,0 #define CALL(x) .equ NR_syscalls,NR_syscalls+1 #include "calls.S" #undef CALL #define CALL(x) .long x /*============================================================================= * SWI handler *----------------------------------------------------------------------------- */ /* If we're optimising for StrongARM the resulting code won't run on an ARM7 and we can save a couple of instructions. --pb */ #ifdef CONFIG_CPU_ARM710 #define A710(code...) code .Larm710bug: ldmia sp, {r0 - lr}^ @ Get calling r0 - lr mov r0, r0 add sp, sp, #S_FRAME_SIZE subs pc, lr, #4 #else #define A710(code...) #endif .align 5 ENTRY(vector_swi) sub sp, sp, #S_FRAME_SIZE stmia sp, {r0 - r12} @ Calling r0 - r12 add r8, sp, #S_PC stmdb r8, {sp, lr}^ @ Calling sp, lr mrs r8, spsr @ called from non-FIQ mode, so ok. str lr, [sp, #S_PC] @ Save calling PC str r8, [sp, #S_PSR] @ Save CPSR str r0, [sp, #S_OLD_R0] @ Save OLD_R0 zero_fp /* * Get the system call number. */ #if defined(CONFIG_OABI_COMPAT) /* * If we have CONFIG_OABI_COMPAT then we need to look at the swi * value to determine if it is an EABI or an old ABI call. */ #ifdef CONFIG_ARM_THUMB tst r8, #PSR_T_BIT movne r10, #0 @ no thumb OABI emulation ldreq r10, [lr, #-4] @ get SWI instruction #else ldr r10, [lr, #-4] @ get SWI instruction A710( and ip, r10, #0x0f000000 @ check for SWI ) A710( teq ip, #0x0f000000 ) A710( bne .Larm710bug ) #endif #elif defined(CONFIG_AEABI) /* * Pure EABI user space always put syscall number into scno (r7). */ A710( ldr ip, [lr, #-4] @ get SWI instruction ) A710( and ip, ip, #0x0f000000 @ check for SWI ) A710( teq ip, #0x0f000000 ) A710( bne .Larm710bug ) #elif defined(CONFIG_ARM_THUMB) /* Legacy ABI only, possibly thumb mode. */ tst r8, #PSR_T_BIT @ this is SPSR from save_user_regs addne scno, r7, #__NR_SYSCALL_BASE @ put OS number in ldreq scno, [lr, #-4] #else /* Legacy ABI only. */ ldr scno, [lr, #-4] @ get SWI instruction A710( and ip, scno, #0x0f000000 @ check for SWI ) A710( teq ip, #0x0f000000 ) A710( bne .Larm710bug ) #endif #ifdef CONFIG_ALIGNMENT_TRAP ldr ip, __cr_alignment ldr ip, [ip] mcr p15, 0, ip, c1, c0 @ update control register #endif enable_irq get_thread_info tsk adr tbl, sys_call_table @ load syscall table pointer ldr ip, [tsk, #TI_FLAGS] @ check for syscall tracing #if defined(CONFIG_OABI_COMPAT) /* * If the swi argument is zero, this is an EABI call and we do nothing. * * If this is an old ABI call, get the syscall number into scno and * get the old ABI syscall table address. */ bics r10, r10, #0xff000000 eorne scno, r10, #__NR_OABI_SYSCALL_BASE ldrne tbl, =sys_oabi_call_table #elif !defined(CONFIG_AEABI) bic scno, scno, #0xff000000 @ mask off SWI op-code eor scno, scno, #__NR_SYSCALL_BASE @ check OS number #endif stmdb sp!, {r4, r5} @ push fifth and sixth args tst ip, #_TIF_SYSCALL_TRACE @ are we tracing syscalls? bne __sys_trace cmp scno, #NR_syscalls @ check upper syscall limit adr lr, ret_fast_syscall @ return address ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine add r1, sp, #S_OFF 2: mov why, #0 @ no longer a real syscall cmp scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE) eor r0, scno, #__NR_SYSCALL_BASE @ put OS number back bcs arm_syscall b sys_ni_syscall @ not private func /* * This is the really slow path. We're going to be doing * context switches, and waiting for our parent to respond. */ __sys_trace: mov r2, scno add r1, sp, #S_OFF mov r0, #0 @ trace entry [IP = 0] bl syscall_trace adr lr, __sys_trace_return @ return address mov scno, r0 @ syscall number (possibly new) add r1, sp, #S_R0 + S_OFF @ pointer to regs cmp scno, #NR_syscalls @ check upper syscall limit ldmccia r1, {r0 - r3} @ have to reload r0 - r3 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine b 2b __sys_trace_return: str r0, [sp, #S_R0 + S_OFF]! @ save returned r0 mov r2, scno mov r1, sp mov r0, #1 @ trace exit [IP = 1] bl syscall_trace b ret_slow_syscall .align 5 #ifdef CONFIG_ALIGNMENT_TRAP .type __cr_alignment, #object __cr_alignment: .word cr_alignment #endif .ltorg /* * This is the syscall table declaration for native ABI syscalls. * With EABI a couple syscalls are obsolete and defined as sys_ni_syscall. */ #define ABI(native, compat) native #ifdef CONFIG_AEABI #define OBSOLETE(syscall) sys_ni_syscall #else #define OBSOLETE(syscall) syscall #endif .type sys_call_table, #object ENTRY(sys_call_table) #include "calls.S" #undef ABI #undef OBSOLETE /*============================================================================ * Special system call wrappers */ @ r0 = syscall number @ r8 = syscall table .type sys_syscall, #function sys_syscall: bic scno, r0, #__NR_OABI_SYSCALL_BASE cmp scno, #__NR_syscall - __NR_SYSCALL_BASE cmpne scno, #NR_syscalls @ check range stmloia sp, {r5, r6} @ shuffle args movlo r0, r1 movlo r1, r2 movlo r2, r3 movlo r3, r4 ldrlo pc, [tbl, scno, lsl #2] b sys_ni_syscall sys_fork_wrapper: add r0, sp, #S_OFF b sys_fork sys_vfork_wrapper: add r0, sp, #S_OFF b sys_vfork sys_execve_wrapper: add r3, sp, #S_OFF b sys_execve sys_clone_wrapper: add ip, sp, #S_OFF str ip, [sp, #4] b sys_clone sys_sigsuspend_wrapper: add r3, sp, #S_OFF b sys_sigsuspend sys_rt_sigsuspend_wrapper: add r2, sp, #S_OFF b sys_rt_sigsuspend sys_sigreturn_wrapper: add r0, sp, #S_OFF b sys_sigreturn sys_rt_sigreturn_wrapper: add r0, sp, #S_OFF b sys_rt_sigreturn sys_sigaltstack_wrapper: ldr r2, [sp, #S_OFF + S_SP] b do_sigaltstack sys_statfs64_wrapper: teq r1, #88 moveq r1, #84 b sys_statfs64 sys_fstatfs64_wrapper: teq r1, #88 moveq r1, #84 b sys_fstatfs64 /* * Note: off_4k (r5) is always units of 4K. If we can't do the requested * offset, we return EINVAL. */ sys_mmap2: #if PAGE_SHIFT > 12 tst r5, #PGOFF_MASK moveq r5, r5, lsr #PAGE_SHIFT - 12 streq r5, [sp, #4] beq do_mmap2 mov r0, #-EINVAL mov pc, lr #else str r5, [sp, #4] b do_mmap2 #endif #ifdef CONFIG_OABI_COMPAT /* * These are syscalls with argument register differences */ sys_oabi_pread64: stmia sp, {r3, r4} b sys_pread64 sys_oabi_pwrite64: stmia sp, {r3, r4} b sys_pwrite64 sys_oabi_truncate64: mov r3, r2 mov r2, r1 b sys_truncate64 sys_oabi_ftruncate64: mov r3, r2 mov r2, r1 b sys_ftruncate64 sys_oabi_readahead: str r3, [sp] mov r3, r2 mov r2, r1 b sys_readahead /* * Let's declare a second syscall table for old ABI binaries * using the compatibility syscall entries. */ #define ABI(native, compat) compat #define OBSOLETE(syscall) syscall .type sys_oabi_call_table, #object ENTRY(sys_oabi_call_table) #include "calls.S" #undef ABI #undef OBSOLETE #endif