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463 lines
11 KiB
463 lines
11 KiB
/* SPDX-License-Identifier: GPL-2.0-only */ |
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/* |
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* linux/arch/arm/kernel/entry-common.S |
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* |
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* Copyright (C) 2000 Russell King |
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*/ |
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#include <asm/assembler.h> |
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#include <asm/unistd.h> |
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#include <asm/ftrace.h> |
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#include <asm/unwind.h> |
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#include <asm/memory.h> |
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#ifdef CONFIG_AEABI |
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#include <asm/unistd-oabi.h> |
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#endif |
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.equ NR_syscalls, __NR_syscalls |
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#ifdef CONFIG_NEED_RET_TO_USER |
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#include <mach/entry-macro.S> |
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#else |
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.macro arch_ret_to_user, tmp1, tmp2 |
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.endm |
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#endif |
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#include "entry-header.S" |
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saved_psr .req r8 |
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#if defined(CONFIG_TRACE_IRQFLAGS) || defined(CONFIG_CONTEXT_TRACKING) |
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saved_pc .req r9 |
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#define TRACE(x...) x |
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#else |
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saved_pc .req lr |
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#define TRACE(x...) |
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#endif |
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.section .entry.text,"ax",%progbits |
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.align 5 |
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#if !(IS_ENABLED(CONFIG_TRACE_IRQFLAGS) || IS_ENABLED(CONFIG_CONTEXT_TRACKING) || \ |
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IS_ENABLED(CONFIG_DEBUG_RSEQ)) |
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/* |
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* This is the fast syscall return path. We do as little as possible here, |
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* such as avoiding writing r0 to the stack. We only use this path if we |
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* have tracing, context tracking and rseq debug disabled - the overheads |
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* from those features make this path too inefficient. |
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*/ |
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ret_fast_syscall: |
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__ret_fast_syscall: |
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UNWIND(.fnstart ) |
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UNWIND(.cantunwind ) |
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disable_irq_notrace @ disable interrupts |
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ldr r2, [tsk, #TI_ADDR_LIMIT] |
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ldr r1, =TASK_SIZE |
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cmp r2, r1 |
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blne addr_limit_check_failed |
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ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing |
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movs r1, r1, lsl #16 |
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bne fast_work_pending |
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/* perform architecture specific actions before user return */ |
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arch_ret_to_user r1, lr |
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restore_user_regs fast = 1, offset = S_OFF |
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UNWIND(.fnend ) |
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ENDPROC(ret_fast_syscall) |
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/* Ok, we need to do extra processing, enter the slow path. */ |
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fast_work_pending: |
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str r0, [sp, #S_R0+S_OFF]! @ returned r0 |
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/* fall through to work_pending */ |
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#else |
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/* |
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* The "replacement" ret_fast_syscall for when tracing, context tracking, |
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* or rseq debug is enabled. As we will need to call out to some C functions, |
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* we save r0 first to avoid needing to save registers around each C function |
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* call. |
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*/ |
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ret_fast_syscall: |
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__ret_fast_syscall: |
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UNWIND(.fnstart ) |
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UNWIND(.cantunwind ) |
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str r0, [sp, #S_R0 + S_OFF]! @ save returned r0 |
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#if IS_ENABLED(CONFIG_DEBUG_RSEQ) |
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/* do_rseq_syscall needs interrupts enabled. */ |
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mov r0, sp @ 'regs' |
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bl do_rseq_syscall |
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#endif |
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disable_irq_notrace @ disable interrupts |
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ldr r2, [tsk, #TI_ADDR_LIMIT] |
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ldr r1, =TASK_SIZE |
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cmp r2, r1 |
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blne addr_limit_check_failed |
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ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing |
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movs r1, r1, lsl #16 |
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beq no_work_pending |
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UNWIND(.fnend ) |
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ENDPROC(ret_fast_syscall) |
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/* Slower path - fall through to work_pending */ |
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#endif |
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tst r1, #_TIF_SYSCALL_WORK |
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bne __sys_trace_return_nosave |
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slow_work_pending: |
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mov r0, sp @ 'regs' |
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mov r2, why @ 'syscall' |
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bl do_work_pending |
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cmp r0, #0 |
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beq no_work_pending |
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movlt scno, #(__NR_restart_syscall - __NR_SYSCALL_BASE) |
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ldmia sp, {r0 - r6} @ have to reload r0 - r6 |
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b local_restart @ ... and off we go |
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ENDPROC(ret_fast_syscall) |
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/* |
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* "slow" syscall return path. "why" tells us if this was a real syscall. |
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* IRQs may be enabled here, so always disable them. Note that we use the |
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* "notrace" version to avoid calling into the tracing code unnecessarily. |
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* do_work_pending() will update this state if necessary. |
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*/ |
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ENTRY(ret_to_user) |
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ret_slow_syscall: |
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#if IS_ENABLED(CONFIG_DEBUG_RSEQ) |
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/* do_rseq_syscall needs interrupts enabled. */ |
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enable_irq_notrace @ enable interrupts |
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mov r0, sp @ 'regs' |
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bl do_rseq_syscall |
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#endif |
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disable_irq_notrace @ disable interrupts |
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ENTRY(ret_to_user_from_irq) |
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ldr r2, [tsk, #TI_ADDR_LIMIT] |
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ldr r1, =TASK_SIZE |
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cmp r2, r1 |
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blne addr_limit_check_failed |
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ldr r1, [tsk, #TI_FLAGS] |
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movs r1, r1, lsl #16 |
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bne slow_work_pending |
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no_work_pending: |
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asm_trace_hardirqs_on save = 0 |
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/* perform architecture specific actions before user return */ |
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arch_ret_to_user r1, lr |
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ct_user_enter save = 0 |
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restore_user_regs fast = 0, offset = 0 |
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ENDPROC(ret_to_user_from_irq) |
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ENDPROC(ret_to_user) |
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/* |
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* This is how we return from a fork. |
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*/ |
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ENTRY(ret_from_fork) |
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bl schedule_tail |
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cmp r5, #0 |
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movne r0, r4 |
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badrne lr, 1f |
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retne r5 |
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1: get_thread_info tsk |
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b ret_slow_syscall |
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ENDPROC(ret_from_fork) |
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/*============================================================================= |
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* SWI handler |
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*----------------------------------------------------------------------------- |
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*/ |
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.align 5 |
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ENTRY(vector_swi) |
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#ifdef CONFIG_CPU_V7M |
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v7m_exception_entry |
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#else |
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sub sp, sp, #PT_REGS_SIZE |
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stmia sp, {r0 - r12} @ Calling r0 - r12 |
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ARM( add r8, sp, #S_PC ) |
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ARM( stmdb r8, {sp, lr}^ ) @ Calling sp, lr |
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THUMB( mov r8, sp ) |
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THUMB( store_user_sp_lr r8, r10, S_SP ) @ calling sp, lr |
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mrs saved_psr, spsr @ called from non-FIQ mode, so ok. |
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TRACE( mov saved_pc, lr ) |
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str saved_pc, [sp, #S_PC] @ Save calling PC |
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str saved_psr, [sp, #S_PSR] @ Save CPSR |
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str r0, [sp, #S_OLD_R0] @ Save OLD_R0 |
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#endif |
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zero_fp |
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alignment_trap r10, ip, __cr_alignment |
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asm_trace_hardirqs_on save=0 |
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enable_irq_notrace |
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ct_user_exit save=0 |
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/* |
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* Get the system call number. |
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*/ |
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#if defined(CONFIG_OABI_COMPAT) |
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/* |
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* If we have CONFIG_OABI_COMPAT then we need to look at the swi |
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* value to determine if it is an EABI or an old ABI call. |
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*/ |
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#ifdef CONFIG_ARM_THUMB |
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tst saved_psr, #PSR_T_BIT |
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movne r10, #0 @ no thumb OABI emulation |
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USER( ldreq r10, [saved_pc, #-4] ) @ get SWI instruction |
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#else |
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USER( ldr r10, [saved_pc, #-4] ) @ get SWI instruction |
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#endif |
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ARM_BE8(rev r10, r10) @ little endian instruction |
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#elif defined(CONFIG_AEABI) |
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/* |
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* Pure EABI user space always put syscall number into scno (r7). |
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*/ |
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#elif defined(CONFIG_ARM_THUMB) |
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/* Legacy ABI only, possibly thumb mode. */ |
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tst saved_psr, #PSR_T_BIT @ this is SPSR from save_user_regs |
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addne scno, r7, #__NR_SYSCALL_BASE @ put OS number in |
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USER( ldreq scno, [saved_pc, #-4] ) |
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#else |
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/* Legacy ABI only. */ |
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USER( ldr scno, [saved_pc, #-4] ) @ get SWI instruction |
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#endif |
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/* saved_psr and saved_pc are now dead */ |
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uaccess_disable tbl |
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adr tbl, sys_call_table @ load syscall table pointer |
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#if defined(CONFIG_OABI_COMPAT) |
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/* |
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* If the swi argument is zero, this is an EABI call and we do nothing. |
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* |
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* If this is an old ABI call, get the syscall number into scno and |
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* get the old ABI syscall table address. |
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*/ |
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bics r10, r10, #0xff000000 |
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eorne scno, r10, #__NR_OABI_SYSCALL_BASE |
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ldrne tbl, =sys_oabi_call_table |
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#elif !defined(CONFIG_AEABI) |
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bic scno, scno, #0xff000000 @ mask off SWI op-code |
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eor scno, scno, #__NR_SYSCALL_BASE @ check OS number |
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#endif |
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get_thread_info tsk |
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/* |
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* Reload the registers that may have been corrupted on entry to |
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* the syscall assembly (by tracing or context tracking.) |
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*/ |
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TRACE( ldmia sp, {r0 - r3} ) |
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local_restart: |
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ldr r10, [tsk, #TI_FLAGS] @ check for syscall tracing |
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stmdb sp!, {r4, r5} @ push fifth and sixth args |
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tst r10, #_TIF_SYSCALL_WORK @ are we tracing syscalls? |
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bne __sys_trace |
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invoke_syscall tbl, scno, r10, __ret_fast_syscall |
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add r1, sp, #S_OFF |
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2: cmp scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE) |
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eor r0, scno, #__NR_SYSCALL_BASE @ put OS number back |
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bcs arm_syscall |
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mov why, #0 @ no longer a real syscall |
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b sys_ni_syscall @ not private func |
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#if defined(CONFIG_OABI_COMPAT) || !defined(CONFIG_AEABI) |
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/* |
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* We failed to handle a fault trying to access the page |
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* containing the swi instruction, but we're not really in a |
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* position to return -EFAULT. Instead, return back to the |
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* instruction and re-enter the user fault handling path trying |
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* to page it in. This will likely result in sending SEGV to the |
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* current task. |
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*/ |
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9001: |
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sub lr, saved_pc, #4 |
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str lr, [sp, #S_PC] |
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get_thread_info tsk |
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b ret_fast_syscall |
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#endif |
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ENDPROC(vector_swi) |
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/* |
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* This is the really slow path. We're going to be doing |
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* context switches, and waiting for our parent to respond. |
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*/ |
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__sys_trace: |
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mov r1, scno |
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add r0, sp, #S_OFF |
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bl syscall_trace_enter |
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mov scno, r0 |
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invoke_syscall tbl, scno, r10, __sys_trace_return, reload=1 |
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cmp scno, #-1 @ skip the syscall? |
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bne 2b |
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add sp, sp, #S_OFF @ restore stack |
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__sys_trace_return_nosave: |
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enable_irq_notrace |
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mov r0, sp |
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bl syscall_trace_exit |
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b ret_slow_syscall |
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__sys_trace_return: |
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str r0, [sp, #S_R0 + S_OFF]! @ save returned r0 |
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mov r0, sp |
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bl syscall_trace_exit |
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b ret_slow_syscall |
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.align 5 |
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#ifdef CONFIG_ALIGNMENT_TRAP |
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.type __cr_alignment, #object |
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__cr_alignment: |
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.word cr_alignment |
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#endif |
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.ltorg |
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.macro syscall_table_start, sym |
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.equ __sys_nr, 0 |
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.type \sym, #object |
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ENTRY(\sym) |
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.endm |
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.macro syscall, nr, func |
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.ifgt __sys_nr - \nr |
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.error "Duplicated/unorded system call entry" |
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.endif |
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.rept \nr - __sys_nr |
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.long sys_ni_syscall |
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.endr |
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.long \func |
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.equ __sys_nr, \nr + 1 |
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.endm |
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.macro syscall_table_end, sym |
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.ifgt __sys_nr - __NR_syscalls |
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.error "System call table too big" |
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.endif |
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.rept __NR_syscalls - __sys_nr |
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.long sys_ni_syscall |
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.endr |
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.size \sym, . - \sym |
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.endm |
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#define NATIVE(nr, func) syscall nr, func |
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/* |
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* This is the syscall table declaration for native ABI syscalls. |
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* With EABI a couple syscalls are obsolete and defined as sys_ni_syscall. |
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*/ |
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syscall_table_start sys_call_table |
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#define COMPAT(nr, native, compat) syscall nr, native |
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#ifdef CONFIG_AEABI |
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#include <calls-eabi.S> |
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#else |
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#include <calls-oabi.S> |
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#endif |
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#undef COMPAT |
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syscall_table_end sys_call_table |
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/*============================================================================ |
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* Special system call wrappers |
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*/ |
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@ r0 = syscall number |
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@ r8 = syscall table |
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sys_syscall: |
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bic scno, r0, #__NR_OABI_SYSCALL_BASE |
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cmp scno, #__NR_syscall - __NR_SYSCALL_BASE |
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cmpne scno, #NR_syscalls @ check range |
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#ifdef CONFIG_CPU_SPECTRE |
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movhs scno, #0 |
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csdb |
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#endif |
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stmialo sp, {r5, r6} @ shuffle args |
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movlo r0, r1 |
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movlo r1, r2 |
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movlo r2, r3 |
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movlo r3, r4 |
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ldrlo pc, [tbl, scno, lsl #2] |
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b sys_ni_syscall |
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ENDPROC(sys_syscall) |
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sys_sigreturn_wrapper: |
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add r0, sp, #S_OFF |
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mov why, #0 @ prevent syscall restart handling |
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b sys_sigreturn |
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ENDPROC(sys_sigreturn_wrapper) |
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sys_rt_sigreturn_wrapper: |
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add r0, sp, #S_OFF |
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mov why, #0 @ prevent syscall restart handling |
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b sys_rt_sigreturn |
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ENDPROC(sys_rt_sigreturn_wrapper) |
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sys_statfs64_wrapper: |
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teq r1, #88 |
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moveq r1, #84 |
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b sys_statfs64 |
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ENDPROC(sys_statfs64_wrapper) |
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sys_fstatfs64_wrapper: |
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teq r1, #88 |
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moveq r1, #84 |
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b sys_fstatfs64 |
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ENDPROC(sys_fstatfs64_wrapper) |
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/* |
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* Note: off_4k (r5) is always units of 4K. If we can't do the requested |
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* offset, we return EINVAL. |
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*/ |
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sys_mmap2: |
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str r5, [sp, #4] |
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b sys_mmap_pgoff |
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ENDPROC(sys_mmap2) |
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#ifdef CONFIG_OABI_COMPAT |
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/* |
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* These are syscalls with argument register differences |
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*/ |
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sys_oabi_pread64: |
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stmia sp, {r3, r4} |
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b sys_pread64 |
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ENDPROC(sys_oabi_pread64) |
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sys_oabi_pwrite64: |
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stmia sp, {r3, r4} |
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b sys_pwrite64 |
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ENDPROC(sys_oabi_pwrite64) |
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sys_oabi_truncate64: |
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mov r3, r2 |
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mov r2, r1 |
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b sys_truncate64 |
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ENDPROC(sys_oabi_truncate64) |
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sys_oabi_ftruncate64: |
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mov r3, r2 |
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mov r2, r1 |
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b sys_ftruncate64 |
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ENDPROC(sys_oabi_ftruncate64) |
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sys_oabi_readahead: |
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str r3, [sp] |
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mov r3, r2 |
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mov r2, r1 |
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b sys_readahead |
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ENDPROC(sys_oabi_readahead) |
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/* |
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* Let's declare a second syscall table for old ABI binaries |
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* using the compatibility syscall entries. |
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*/ |
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syscall_table_start sys_oabi_call_table |
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#define COMPAT(nr, native, compat) syscall nr, compat |
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#include <calls-oabi.S> |
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syscall_table_end sys_oabi_call_table |
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#endif |
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