| /* SPDX-License-Identifier: GPL-2.0-only */ |
| /* |
| * linux/arch/arm/kernel/entry-common.S |
| * |
| * Copyright (C) 2000 Russell King |
| */ |
| |
| #include <asm/assembler.h> |
| #include <asm/unistd.h> |
| #include <asm/ftrace.h> |
| #include <asm/unwind.h> |
| #include <asm/memory.h> |
| #ifdef CONFIG_AEABI |
| #include <asm/unistd-oabi.h> |
| #endif |
| |
| .equ NR_syscalls, __NR_syscalls |
| |
| .macro arch_ret_to_user, tmp |
| #ifdef CONFIG_ARCH_IOP32X |
| mrc p15, 0, \tmp, c15, c1, 0 |
| tst \tmp, #(1 << 6) |
| bicne \tmp, \tmp, #(1 << 6) |
| mcrne p15, 0, \tmp, c15, c1, 0 @ Disable cp6 access |
| #endif |
| .endm |
| |
| #include "entry-header.S" |
| |
| saved_psr .req r8 |
| #if defined(CONFIG_TRACE_IRQFLAGS) || defined(CONFIG_CONTEXT_TRACKING) |
| saved_pc .req r9 |
| #define TRACE(x...) x |
| #else |
| saved_pc .req lr |
| #define TRACE(x...) |
| #endif |
| |
| .section .entry.text,"ax",%progbits |
| .align 5 |
| #if !(IS_ENABLED(CONFIG_TRACE_IRQFLAGS) || IS_ENABLED(CONFIG_CONTEXT_TRACKING) || \ |
| IS_ENABLED(CONFIG_DEBUG_RSEQ)) |
| /* |
| * This is the fast syscall return path. We do as little as possible here, |
| * such as avoiding writing r0 to the stack. We only use this path if we |
| * have tracing, context tracking and rseq debug disabled - the overheads |
| * from those features make this path too inefficient. |
| */ |
| ret_fast_syscall: |
| __ret_fast_syscall: |
| UNWIND(.fnstart ) |
| UNWIND(.cantunwind ) |
| disable_irq_notrace @ disable interrupts |
| ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing |
| movs r1, r1, lsl #16 |
| bne fast_work_pending |
| |
| |
| /* perform architecture specific actions before user return */ |
| arch_ret_to_user r1 |
| |
| restore_user_regs fast = 1, offset = S_OFF |
| UNWIND(.fnend ) |
| ENDPROC(ret_fast_syscall) |
| |
| /* Ok, we need to do extra processing, enter the slow path. */ |
| fast_work_pending: |
| str r0, [sp, #S_R0+S_OFF]! @ returned r0 |
| /* fall through to work_pending */ |
| #else |
| /* |
| * The "replacement" ret_fast_syscall for when tracing, context tracking, |
| * or rseq debug is enabled. As we will need to call out to some C functions, |
| * we save r0 first to avoid needing to save registers around each C function |
| * call. |
| */ |
| ret_fast_syscall: |
| __ret_fast_syscall: |
| UNWIND(.fnstart ) |
| UNWIND(.cantunwind ) |
| str r0, [sp, #S_R0 + S_OFF]! @ save returned r0 |
| #if IS_ENABLED(CONFIG_DEBUG_RSEQ) |
| /* do_rseq_syscall needs interrupts enabled. */ |
| mov r0, sp @ 'regs' |
| bl do_rseq_syscall |
| #endif |
| disable_irq_notrace @ disable interrupts |
| ldr r1, [tsk, #TI_FLAGS] @ re-check for syscall tracing |
| movs r1, r1, lsl #16 |
| beq no_work_pending |
| UNWIND(.fnend ) |
| ENDPROC(ret_fast_syscall) |
| |
| /* Slower path - fall through to work_pending */ |
| #endif |
| |
| tst r1, #_TIF_SYSCALL_WORK |
| bne __sys_trace_return_nosave |
| slow_work_pending: |
| mov r0, sp @ 'regs' |
| mov r2, why @ 'syscall' |
| bl do_work_pending |
| cmp r0, #0 |
| beq no_work_pending |
| movlt scno, #(__NR_restart_syscall - __NR_SYSCALL_BASE) |
| ldmia sp, {r0 - r6} @ have to reload r0 - r6 |
| b local_restart @ ... and off we go |
| ENDPROC(ret_fast_syscall) |
| |
| /* |
| * "slow" syscall return path. "why" tells us if this was a real syscall. |
| * IRQs may be enabled here, so always disable them. Note that we use the |
| * "notrace" version to avoid calling into the tracing code unnecessarily. |
| * do_work_pending() will update this state if necessary. |
| */ |
| ENTRY(ret_to_user) |
| ret_slow_syscall: |
| #if IS_ENABLED(CONFIG_DEBUG_RSEQ) |
| /* do_rseq_syscall needs interrupts enabled. */ |
| enable_irq_notrace @ enable interrupts |
| mov r0, sp @ 'regs' |
| bl do_rseq_syscall |
| #endif |
| disable_irq_notrace @ disable interrupts |
| ENTRY(ret_to_user_from_irq) |
| ldr r1, [tsk, #TI_FLAGS] |
| movs r1, r1, lsl #16 |
| bne slow_work_pending |
| no_work_pending: |
| asm_trace_hardirqs_on save = 0 |
| |
| /* perform architecture specific actions before user return */ |
| arch_ret_to_user r1 |
| ct_user_enter save = 0 |
| |
| restore_user_regs fast = 0, offset = 0 |
| ENDPROC(ret_to_user_from_irq) |
| ENDPROC(ret_to_user) |
| |
| /* |
| * This is how we return from a fork. |
| */ |
| ENTRY(ret_from_fork) |
| bl schedule_tail |
| cmp r5, #0 |
| movne r0, r4 |
| badrne lr, 1f |
| retne r5 |
| 1: get_thread_info tsk |
| b ret_slow_syscall |
| ENDPROC(ret_from_fork) |
| |
| /*============================================================================= |
| * SWI handler |
| *----------------------------------------------------------------------------- |
| */ |
| |
| .align 5 |
| #ifdef CONFIG_HARDEN_BRANCH_HISTORY |
| ENTRY(vector_bhb_loop8_swi) |
| sub sp, sp, #PT_REGS_SIZE |
| stmia sp, {r0 - r12} |
| mov r8, #8 |
| 1: b 2f |
| 2: subs r8, r8, #1 |
| bne 1b |
| dsb nsh |
| isb |
| b 3f |
| ENDPROC(vector_bhb_loop8_swi) |
| |
| .align 5 |
| ENTRY(vector_bhb_bpiall_swi) |
| sub sp, sp, #PT_REGS_SIZE |
| stmia sp, {r0 - r12} |
| mcr p15, 0, r8, c7, c5, 6 @ BPIALL |
| isb |
| b 3f |
| ENDPROC(vector_bhb_bpiall_swi) |
| #endif |
| .align 5 |
| ENTRY(vector_swi) |
| #ifdef CONFIG_CPU_V7M |
| v7m_exception_entry |
| #else |
| sub sp, sp, #PT_REGS_SIZE |
| stmia sp, {r0 - r12} @ Calling r0 - r12 |
| 3: |
| ARM( add r8, sp, #S_PC ) |
| ARM( stmdb r8, {sp, lr}^ ) @ Calling sp, lr |
| THUMB( mov r8, sp ) |
| THUMB( store_user_sp_lr r8, r10, S_SP ) @ calling sp, lr |
| mrs saved_psr, spsr @ called from non-FIQ mode, so ok. |
| TRACE( mov saved_pc, lr ) |
| str saved_pc, [sp, #S_PC] @ Save calling PC |
| str saved_psr, [sp, #S_PSR] @ Save CPSR |
| str r0, [sp, #S_OLD_R0] @ Save OLD_R0 |
| #endif |
| reload_current r10, ip |
| zero_fp |
| alignment_trap r10, ip, cr_alignment |
| asm_trace_hardirqs_on save=0 |
| enable_irq_notrace |
| ct_user_exit save=0 |
| |
| /* |
| * 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 saved_psr, #PSR_T_BIT |
| movne r10, #0 @ no thumb OABI emulation |
| USER( ldreq r10, [saved_pc, #-4] ) @ get SWI instruction |
| #else |
| USER( ldr r10, [saved_pc, #-4] ) @ get SWI instruction |
| #endif |
| ARM_BE8(rev r10, r10) @ little endian instruction |
| |
| #elif defined(CONFIG_AEABI) |
| |
| /* |
| * Pure EABI user space always put syscall number into scno (r7). |
| */ |
| #elif defined(CONFIG_ARM_THUMB) |
| /* Legacy ABI only, possibly thumb mode. */ |
| tst saved_psr, #PSR_T_BIT @ this is SPSR from save_user_regs |
| addne scno, r7, #__NR_SYSCALL_BASE @ put OS number in |
| USER( ldreq scno, [saved_pc, #-4] ) |
| |
| #else |
| /* Legacy ABI only. */ |
| USER( ldr scno, [saved_pc, #-4] ) @ get SWI instruction |
| #endif |
| |
| /* saved_psr and saved_pc are now dead */ |
| |
| uaccess_disable tbl |
| get_thread_info tsk |
| |
| adr tbl, sys_call_table @ load syscall table pointer |
| |
| #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 |
| strne r10, [tsk, #TI_ABI_SYSCALL] |
| streq scno, [tsk, #TI_ABI_SYSCALL] |
| 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 |
| str scno, [tsk, #TI_ABI_SYSCALL] |
| eor scno, scno, #__NR_SYSCALL_BASE @ check OS number |
| #else |
| str scno, [tsk, #TI_ABI_SYSCALL] |
| #endif |
| /* |
| * Reload the registers that may have been corrupted on entry to |
| * the syscall assembly (by tracing or context tracking.) |
| */ |
| TRACE( ldmia sp, {r0 - r3} ) |
| |
| local_restart: |
| ldr r10, [tsk, #TI_FLAGS] @ check for syscall tracing |
| stmdb sp!, {r4, r5} @ push fifth and sixth args |
| |
| tst r10, #_TIF_SYSCALL_WORK @ are we tracing syscalls? |
| bne __sys_trace |
| |
| invoke_syscall tbl, scno, r10, __ret_fast_syscall |
| |
| add r1, sp, #S_OFF |
| 2: cmp scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE) |
| eor r0, scno, #__NR_SYSCALL_BASE @ put OS number back |
| bcs arm_syscall |
| mov why, #0 @ no longer a real syscall |
| b sys_ni_syscall @ not private func |
| |
| #if defined(CONFIG_OABI_COMPAT) || !defined(CONFIG_AEABI) |
| /* |
| * We failed to handle a fault trying to access the page |
| * containing the swi instruction, but we're not really in a |
| * position to return -EFAULT. Instead, return back to the |
| * instruction and re-enter the user fault handling path trying |
| * to page it in. This will likely result in sending SEGV to the |
| * current task. |
| */ |
| 9001: |
| sub lr, saved_pc, #4 |
| str lr, [sp, #S_PC] |
| get_thread_info tsk |
| b ret_fast_syscall |
| #endif |
| ENDPROC(vector_swi) |
| |
| /* |
| * This is the really slow path. We're going to be doing |
| * context switches, and waiting for our parent to respond. |
| */ |
| __sys_trace: |
| add r0, sp, #S_OFF |
| bl syscall_trace_enter |
| mov scno, r0 |
| invoke_syscall tbl, scno, r10, __sys_trace_return, reload=1 |
| cmp scno, #-1 @ skip the syscall? |
| bne 2b |
| add sp, sp, #S_OFF @ restore stack |
| |
| __sys_trace_return_nosave: |
| enable_irq_notrace |
| mov r0, sp |
| bl syscall_trace_exit |
| b ret_slow_syscall |
| |
| __sys_trace_return: |
| str r0, [sp, #S_R0 + S_OFF]! @ save returned r0 |
| mov r0, sp |
| bl syscall_trace_exit |
| b ret_slow_syscall |
| |
| .macro syscall_table_start, sym |
| .equ __sys_nr, 0 |
| .type \sym, #object |
| ENTRY(\sym) |
| .endm |
| |
| .macro syscall, nr, func |
| .ifgt __sys_nr - \nr |
| .error "Duplicated/unorded system call entry" |
| .endif |
| .rept \nr - __sys_nr |
| .long sys_ni_syscall |
| .endr |
| .long \func |
| .equ __sys_nr, \nr + 1 |
| .endm |
| |
| .macro syscall_table_end, sym |
| .ifgt __sys_nr - __NR_syscalls |
| .error "System call table too big" |
| .endif |
| .rept __NR_syscalls - __sys_nr |
| .long sys_ni_syscall |
| .endr |
| .size \sym, . - \sym |
| .endm |
| |
| #define __SYSCALL_WITH_COMPAT(nr, native, compat) __SYSCALL(nr, native) |
| #define __SYSCALL(nr, func) syscall nr, func |
| |
| /* |
| * This is the syscall table declaration for native ABI syscalls. |
| * With EABI a couple syscalls are obsolete and defined as sys_ni_syscall. |
| */ |
| syscall_table_start sys_call_table |
| #ifdef CONFIG_AEABI |
| #include <calls-eabi.S> |
| #else |
| #include <calls-oabi.S> |
| #endif |
| syscall_table_end sys_call_table |
| |
| /*============================================================================ |
| * Special system call wrappers |
| */ |
| @ r0 = syscall number |
| @ r8 = syscall table |
| sys_syscall: |
| bic scno, r0, #__NR_OABI_SYSCALL_BASE |
| cmp scno, #__NR_syscall - __NR_SYSCALL_BASE |
| cmpne scno, #NR_syscalls @ check range |
| #ifdef CONFIG_CPU_SPECTRE |
| movhs scno, #0 |
| csdb |
| #endif |
| stmialo 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 |
| ENDPROC(sys_syscall) |
| |
| sys_sigreturn_wrapper: |
| add r0, sp, #S_OFF |
| mov why, #0 @ prevent syscall restart handling |
| b sys_sigreturn |
| ENDPROC(sys_sigreturn_wrapper) |
| |
| sys_rt_sigreturn_wrapper: |
| add r0, sp, #S_OFF |
| mov why, #0 @ prevent syscall restart handling |
| b sys_rt_sigreturn |
| ENDPROC(sys_rt_sigreturn_wrapper) |
| |
| sys_statfs64_wrapper: |
| teq r1, #88 |
| moveq r1, #84 |
| b sys_statfs64 |
| ENDPROC(sys_statfs64_wrapper) |
| |
| sys_fstatfs64_wrapper: |
| teq r1, #88 |
| moveq r1, #84 |
| b sys_fstatfs64 |
| ENDPROC(sys_fstatfs64_wrapper) |
| |
| /* |
| * Note: off_4k (r5) is always units of 4K. If we can't do the requested |
| * offset, we return EINVAL. |
| */ |
| sys_mmap2: |
| str r5, [sp, #4] |
| b sys_mmap_pgoff |
| ENDPROC(sys_mmap2) |
| |
| #ifdef CONFIG_OABI_COMPAT |
| |
| /* |
| * These are syscalls with argument register differences |
| */ |
| |
| sys_oabi_pread64: |
| stmia sp, {r3, r4} |
| b sys_pread64 |
| ENDPROC(sys_oabi_pread64) |
| |
| sys_oabi_pwrite64: |
| stmia sp, {r3, r4} |
| b sys_pwrite64 |
| ENDPROC(sys_oabi_pwrite64) |
| |
| sys_oabi_truncate64: |
| mov r3, r2 |
| mov r2, r1 |
| b sys_truncate64 |
| ENDPROC(sys_oabi_truncate64) |
| |
| sys_oabi_ftruncate64: |
| mov r3, r2 |
| mov r2, r1 |
| b sys_ftruncate64 |
| ENDPROC(sys_oabi_ftruncate64) |
| |
| sys_oabi_readahead: |
| str r3, [sp] |
| mov r3, r2 |
| mov r2, r1 |
| b sys_readahead |
| ENDPROC(sys_oabi_readahead) |
| |
| /* |
| * Let's declare a second syscall table for old ABI binaries |
| * using the compatibility syscall entries. |
| */ |
| syscall_table_start sys_oabi_call_table |
| #undef __SYSCALL_WITH_COMPAT |
| #define __SYSCALL_WITH_COMPAT(nr, native, compat) __SYSCALL(nr, compat) |
| #include <calls-oabi.S> |
| syscall_table_end sys_oabi_call_table |
| |
| #endif |
| |