/* * 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 #include #include #include "entry-header.S" /* * We rely on the fact that R0 is at the bottom of the stack (due to * slow/fast restore user regs). */ #if S_R0 != 0 #error "Please fix" #endif .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 r1 @ disable interrupts ldr r1, [tsk, #TI_FLAGS] tst r1, #_TIF_WORK_MASK bne fast_work_pending fast_restore_user_regs /* * 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 disable_irq r1 @ disable interrupts b no_work_pending 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 r1 @ disable interrupts ldr r1, [tsk, #TI_FLAGS] tst r1, #_TIF_WORK_MASK bne work_pending no_work_pending: slow_restore_user_regs /* * 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 #include "calls.S" /*============================================================================= * 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 .macro arm710_bug_check, instr, temp and \temp, \instr, #0x0f000000 @ check for SWI teq \temp, #0x0f000000 bne .Larm700bug .endm .Larm700bug: ldr r0, [sp, #S_PSR] @ Get calling cpsr sub lr, lr, #4 str lr, [r8] msr spsr_cxsf, r0 ldmia sp, {r0 - lr}^ @ Get calling r0 - lr mov r0, r0 ldr lr, [sp, #S_PC] @ Get PC add sp, sp, #S_FRAME_SIZE movs pc, lr #else .macro arm710_bug_check, instr, temp .endm #endif .align 5 ENTRY(vector_swi) save_user_regs zero_fp get_scno arm710_bug_check scno, ip #ifdef CONFIG_ALIGNMENT_TRAP ldr ip, __cr_alignment ldr ip, [ip] mcr p15, 0, ip, c1, c0 @ update control register #endif enable_irq ip str r4, [sp, #-S_OFF]! @ push fifth arg get_thread_info tsk ldr ip, [tsk, #TI_FLAGS] @ check for syscall tracing bic scno, scno, #0xff000000 @ mask off SWI op-code eor scno, scno, #OS_NUMBER << 20 @ check OS number adr tbl, sys_call_table @ load syscall table pointer tst ip, #_TIF_SYSCALL_TRACE @ are we tracing syscalls? bne __sys_trace adrsvc al, lr, ret_fast_syscall @ return address cmp scno, #NR_syscalls @ check upper syscall limit 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, #ARMSWI_OFFSET eor r0, scno, #OS_NUMBER << 20 @ 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: add r1, sp, #S_OFF mov r0, #0 @ trace entry [IP = 0] bl syscall_trace adrsvc al, lr, __sys_trace_return @ return address 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 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 .type sys_call_table, #object ENTRY(sys_call_table) #include "calls.S" /*============================================================================ * Special system call wrappers */ @ r0 = syscall number @ r5 = syscall table .type sys_syscall, #function sys_syscall: eor scno, r0, #OS_NUMBER << 20 cmp scno, #NR_syscalls @ check range stmleia sp, {r5, r6} @ shuffle args movle r0, r1 movle r1, r2 movle r2, r3 movle r3, r4 ldrle 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_wapper: add r2, sp, #S_OFF 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 /* * 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 RETINSTR(mov,pc, lr) #else str r5, [sp, #4] b do_mmap2 #endif