| /* |
| * 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 <asm/ftrace.h> |
| #include <asm/unwind.h> |
| |
| #ifdef CONFIG_NEED_RET_TO_USER |
| #include <mach/entry-macro.S> |
| #else |
| .macro arch_ret_to_user, tmp1, tmp2 |
| .endm |
| #endif |
| |
| #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: |
| UNWIND(.fnstart ) |
| UNWIND(.cantunwind ) |
| disable_irq @ disable interrupts |
| ldr r1, [tsk, #TI_FLAGS] |
| tst r1, #_TIF_WORK_MASK |
| bne fast_work_pending |
| asm_trace_hardirqs_on |
| |
| /* perform architecture specific actions before user return */ |
| arch_ret_to_user r1, lr |
| ct_user_enter |
| |
| restore_user_regs fast = 1, offset = S_OFF |
| UNWIND(.fnend ) |
| |
| /* |
| * 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: |
| 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 |
| |
| /* |
| * "slow" syscall return path. "why" tells us if this was a real syscall. |
| */ |
| ENTRY(ret_to_user) |
| ret_slow_syscall: |
| disable_irq @ disable interrupts |
| ENTRY(ret_to_user_from_irq) |
| ldr r1, [tsk, #TI_FLAGS] |
| tst r1, #_TIF_WORK_MASK |
| bne work_pending |
| no_work_pending: |
| asm_trace_hardirqs_on |
| |
| /* perform architecture specific actions before user return */ |
| arch_ret_to_user r1, lr |
| 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 |
| adrne lr, BSYM(1f) |
| movne pc, r5 |
| 1: get_thread_info tsk |
| b ret_slow_syscall |
| ENDPROC(ret_from_fork) |
| |
| .equ NR_syscalls,0 |
| #define CALL(x) .equ NR_syscalls,NR_syscalls+1 |
| #include "calls.S" |
| |
| /* |
| * Ensure that the system call table is equal to __NR_syscalls, |
| * which is the value the rest of the system sees |
| */ |
| .ifne NR_syscalls - __NR_syscalls |
| .error "__NR_syscalls is not equal to the size of the syscall table" |
| .endif |
| |
| #undef CALL |
| #define CALL(x) .long x |
| |
| #ifdef CONFIG_FUNCTION_TRACER |
| /* |
| * When compiling with -pg, gcc inserts a call to the mcount routine at the |
| * start of every function. In mcount, apart from the function's address (in |
| * lr), we need to get hold of the function's caller's address. |
| * |
| * Older GCCs (pre-4.4) inserted a call to a routine called mcount like this: |
| * |
| * bl mcount |
| * |
| * These versions have the limitation that in order for the mcount routine to |
| * be able to determine the function's caller's address, an APCS-style frame |
| * pointer (which is set up with something like the code below) is required. |
| * |
| * mov ip, sp |
| * push {fp, ip, lr, pc} |
| * sub fp, ip, #4 |
| * |
| * With EABI, these frame pointers are not available unless -mapcs-frame is |
| * specified, and if building as Thumb-2, not even then. |
| * |
| * Newer GCCs (4.4+) solve this problem by introducing a new version of mcount, |
| * with call sites like: |
| * |
| * push {lr} |
| * bl __gnu_mcount_nc |
| * |
| * With these compilers, frame pointers are not necessary. |
| * |
| * mcount can be thought of as a function called in the middle of a subroutine |
| * call. As such, it needs to be transparent for both the caller and the |
| * callee: the original lr needs to be restored when leaving mcount, and no |
| * registers should be clobbered. (In the __gnu_mcount_nc implementation, we |
| * clobber the ip register. This is OK because the ARM calling convention |
| * allows it to be clobbered in subroutines and doesn't use it to hold |
| * parameters.) |
| * |
| * When using dynamic ftrace, we patch out the mcount call by a "mov r0, r0" |
| * for the mcount case, and a "pop {lr}" for the __gnu_mcount_nc case (see |
| * arch/arm/kernel/ftrace.c). |
| */ |
| |
| #ifndef CONFIG_OLD_MCOUNT |
| #if (__GNUC__ < 4 || (__GNUC__ == 4 && __GNUC_MINOR__ < 4)) |
| #error Ftrace requires CONFIG_FRAME_POINTER=y with GCC older than 4.4.0. |
| #endif |
| #endif |
| |
| .macro mcount_adjust_addr rd, rn |
| bic \rd, \rn, #1 @ clear the Thumb bit if present |
| sub \rd, \rd, #MCOUNT_INSN_SIZE |
| .endm |
| |
| .macro __mcount suffix |
| mcount_enter |
| ldr r0, =ftrace_trace_function |
| ldr r2, [r0] |
| adr r0, .Lftrace_stub |
| cmp r0, r2 |
| bne 1f |
| |
| #ifdef CONFIG_FUNCTION_GRAPH_TRACER |
| ldr r1, =ftrace_graph_return |
| ldr r2, [r1] |
| cmp r0, r2 |
| bne ftrace_graph_caller\suffix |
| |
| ldr r1, =ftrace_graph_entry |
| ldr r2, [r1] |
| ldr r0, =ftrace_graph_entry_stub |
| cmp r0, r2 |
| bne ftrace_graph_caller\suffix |
| #endif |
| |
| mcount_exit |
| |
| 1: mcount_get_lr r1 @ lr of instrumented func |
| mcount_adjust_addr r0, lr @ instrumented function |
| adr lr, BSYM(2f) |
| mov pc, r2 |
| 2: mcount_exit |
| .endm |
| |
| .macro __ftrace_caller suffix |
| mcount_enter |
| |
| mcount_get_lr r1 @ lr of instrumented func |
| mcount_adjust_addr r0, lr @ instrumented function |
| |
| .globl ftrace_call\suffix |
| ftrace_call\suffix: |
| bl ftrace_stub |
| |
| #ifdef CONFIG_FUNCTION_GRAPH_TRACER |
| .globl ftrace_graph_call\suffix |
| ftrace_graph_call\suffix: |
| mov r0, r0 |
| #endif |
| |
| mcount_exit |
| .endm |
| |
| .macro __ftrace_graph_caller |
| sub r0, fp, #4 @ &lr of instrumented routine (&parent) |
| #ifdef CONFIG_DYNAMIC_FTRACE |
| @ called from __ftrace_caller, saved in mcount_enter |
| ldr r1, [sp, #16] @ instrumented routine (func) |
| mcount_adjust_addr r1, r1 |
| #else |
| @ called from __mcount, untouched in lr |
| mcount_adjust_addr r1, lr @ instrumented routine (func) |
| #endif |
| mov r2, fp @ frame pointer |
| bl prepare_ftrace_return |
| mcount_exit |
| .endm |
| |
| #ifdef CONFIG_OLD_MCOUNT |
| /* |
| * mcount |
| */ |
| |
| .macro mcount_enter |
| stmdb sp!, {r0-r3, lr} |
| .endm |
| |
| .macro mcount_get_lr reg |
| ldr \reg, [fp, #-4] |
| .endm |
| |
| .macro mcount_exit |
| ldr lr, [fp, #-4] |
| ldmia sp!, {r0-r3, pc} |
| .endm |
| |
| ENTRY(mcount) |
| #ifdef CONFIG_DYNAMIC_FTRACE |
| stmdb sp!, {lr} |
| ldr lr, [fp, #-4] |
| ldmia sp!, {pc} |
| #else |
| __mcount _old |
| #endif |
| ENDPROC(mcount) |
| |
| #ifdef CONFIG_DYNAMIC_FTRACE |
| ENTRY(ftrace_caller_old) |
| __ftrace_caller _old |
| ENDPROC(ftrace_caller_old) |
| #endif |
| |
| #ifdef CONFIG_FUNCTION_GRAPH_TRACER |
| ENTRY(ftrace_graph_caller_old) |
| __ftrace_graph_caller |
| ENDPROC(ftrace_graph_caller_old) |
| #endif |
| |
| .purgem mcount_enter |
| .purgem mcount_get_lr |
| .purgem mcount_exit |
| #endif |
| |
| /* |
| * __gnu_mcount_nc |
| */ |
| |
| .macro mcount_enter |
| /* |
| * This pad compensates for the push {lr} at the call site. Note that we are |
| * unable to unwind through a function which does not otherwise save its lr. |
| */ |
| UNWIND(.pad #4) |
| stmdb sp!, {r0-r3, lr} |
| UNWIND(.save {r0-r3, lr}) |
| .endm |
| |
| .macro mcount_get_lr reg |
| ldr \reg, [sp, #20] |
| .endm |
| |
| .macro mcount_exit |
| ldmia sp!, {r0-r3, ip, lr} |
| mov pc, ip |
| .endm |
| |
| ENTRY(__gnu_mcount_nc) |
| UNWIND(.fnstart) |
| #ifdef CONFIG_DYNAMIC_FTRACE |
| mov ip, lr |
| ldmia sp!, {lr} |
| mov pc, ip |
| #else |
| __mcount |
| #endif |
| UNWIND(.fnend) |
| ENDPROC(__gnu_mcount_nc) |
| |
| #ifdef CONFIG_DYNAMIC_FTRACE |
| ENTRY(ftrace_caller) |
| UNWIND(.fnstart) |
| __ftrace_caller |
| UNWIND(.fnend) |
| ENDPROC(ftrace_caller) |
| #endif |
| |
| #ifdef CONFIG_FUNCTION_GRAPH_TRACER |
| ENTRY(ftrace_graph_caller) |
| UNWIND(.fnstart) |
| __ftrace_graph_caller |
| UNWIND(.fnend) |
| ENDPROC(ftrace_graph_caller) |
| #endif |
| |
| .purgem mcount_enter |
| .purgem mcount_get_lr |
| .purgem mcount_exit |
| |
| #ifdef CONFIG_FUNCTION_GRAPH_TRACER |
| .globl return_to_handler |
| return_to_handler: |
| stmdb sp!, {r0-r3} |
| mov r0, fp @ frame pointer |
| bl ftrace_return_to_handler |
| mov lr, r0 @ r0 has real ret addr |
| ldmia sp!, {r0-r3} |
| mov pc, lr |
| #endif |
| |
| ENTRY(ftrace_stub) |
| .Lftrace_stub: |
| mov pc, lr |
| ENDPROC(ftrace_stub) |
| |
| #endif /* CONFIG_FUNCTION_TRACER */ |
| |
| /*============================================================================= |
| * SWI handler |
| *----------------------------------------------------------------------------- |
| */ |
| |
| .align 5 |
| ENTRY(vector_swi) |
| #ifdef CONFIG_CPU_V7M |
| v7m_exception_entry |
| #else |
| sub sp, sp, #S_FRAME_SIZE |
| stmia sp, {r0 - r12} @ Calling r0 - r12 |
| 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 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 |
| #endif |
| zero_fp |
| |
| #ifdef CONFIG_ALIGNMENT_TRAP |
| ldr ip, __cr_alignment |
| ldr ip, [ip] |
| mcr p15, 0, ip, c1, c0 @ update control register |
| #endif |
| |
| enable_irq |
| ct_user_exit |
| get_thread_info tsk |
| |
| /* |
| * 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 |
| USER( ldreq r10, [lr, #-4] ) @ get SWI instruction |
| #else |
| USER( ldr r10, [lr, #-4] ) @ get SWI instruction |
| #endif |
| #ifdef CONFIG_CPU_ENDIAN_BE8 |
| rev r10, r10 @ little endian instruction |
| #endif |
| |
| #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 r8, #PSR_T_BIT @ this is SPSR from save_user_regs |
| addne scno, r7, #__NR_SYSCALL_BASE @ put OS number in |
| USER( ldreq scno, [lr, #-4] ) |
| |
| #else |
| /* Legacy ABI only. */ |
| USER( ldr scno, [lr, #-4] ) @ get SWI instruction |
| #endif |
| |
| 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 |
| 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 |
| |
| 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 |
| |
| cmp scno, #NR_syscalls @ check upper syscall limit |
| adr lr, BSYM(ret_fast_syscall) @ return address |
| ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine |
| |
| add r1, sp, #S_OFF |
| cmp scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE) |
| eor r0, scno, #__NR_SYSCALL_BASE @ put OS number back |
| bcs arm_syscall |
| 2: 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, lr, #4 |
| str lr, [sp, #S_PC] |
| 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: |
| mov r1, scno |
| add r0, sp, #S_OFF |
| bl syscall_trace_enter |
| |
| adr lr, BSYM(__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 - r6} @ have to reload r0 - r6 |
| stmccia sp, {r4, r5} @ and update the stack args |
| ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine |
| cmp scno, #-1 @ skip the syscall? |
| bne 2b |
| add sp, sp, #S_OFF @ restore stack |
| 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 |
| |
| .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 |
| 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 |
| 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: |
| #if PAGE_SHIFT > 12 |
| tst r5, #PGOFF_MASK |
| moveq r5, r5, lsr #PAGE_SHIFT - 12 |
| streq r5, [sp, #4] |
| beq sys_mmap_pgoff |
| mov r0, #-EINVAL |
| mov pc, lr |
| #else |
| str r5, [sp, #4] |
| b sys_mmap_pgoff |
| #endif |
| 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. |
| */ |
| #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 |
| |