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Diffstat (limited to 'arch/arm/kernel/entry-common.S')
| -rw-r--r-- | arch/arm/kernel/entry-common.S | 647 |
1 files changed, 647 insertions, 0 deletions
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S new file mode 100644 index 00000000..b2a27b6b --- /dev/null +++ b/arch/arm/kernel/entry-common.S @@ -0,0 +1,647 @@ +/* + * 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 <mach/entry-macro.S> +#include <asm/unwind.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: + UNWIND(.fnstart ) + UNWIND(.cantunwind ) + disable_irq @ disable interrupts + ldr r1, [tsk, #TI_FLAGS] + tst r1, #_TIF_WORK_MASK + bne fast_work_pending +#if defined(CONFIG_IRQSOFF_TRACER) + asm_trace_hardirqs_on +#endif + + /* perform architecture specific actions before user return */ + arch_ret_to_user r1, lr + + 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: + tst r1, #_TIF_NEED_RESCHED + bne work_resched + tst r1, #_TIF_SIGPENDING|_TIF_NOTIFY_RESUME + beq no_work_pending + mov r0, sp @ 'regs' + mov r2, why @ 'syscall' + tst r1, #_TIF_SIGPENDING @ delivering a signal? + movne why, #0 @ prevent further restarts + 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 +ENTRY(ret_to_user_from_irq) + ldr r1, [tsk, #TI_FLAGS] + tst r1, #_TIF_WORK_MASK + bne work_pending +no_work_pending: +#if defined(CONFIG_IRQSOFF_TRACER) + asm_trace_hardirqs_on +#endif + /* perform architecture specific actions before user return */ + arch_ret_to_user r1, lr + + 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 + 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 +ENDPROC(ret_from_fork) + + .equ NR_syscalls,0 +#define CALL(x) .equ NR_syscalls,NR_syscalls+1 +#include "calls.S" +#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 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 + mov r0, lr @ instrumented function + sub r0, r0, #MCOUNT_INSN_SIZE + 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 + mov r0, lr @ instrumented function + sub r0, r0, #MCOUNT_INSN_SIZE + + .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) +#else + @ called from __mcount, untouched in lr + mov r1, lr @ instrumented routine (func) +#endif + sub r1, r1, #MCOUNT_INSN_SIZE + 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 + stmdb sp!, {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) +#ifdef CONFIG_DYNAMIC_FTRACE + mov ip, lr + ldmia sp!, {lr} + mov pc, ip +#else + __mcount +#endif +ENDPROC(__gnu_mcount_nc) + +#ifdef CONFIG_DYNAMIC_FTRACE +ENTRY(ftrace_caller) + __ftrace_caller +ENDPROC(ftrace_caller) +#endif + +#ifdef CONFIG_FUNCTION_GRAPH_TRACER +ENTRY(ftrace_graph_caller) + __ftrace_graph_caller +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 + *----------------------------------------------------------------------------- + */ + + /* 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 + 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 + 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 +#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). + */ + 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 + +#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 + + ldr r10, [tsk, #TI_FLAGS] @ check for syscall tracing + stmdb sp!, {r4, r5} @ push fifth and sixth args + +#ifdef CONFIG_SECCOMP + tst r10, #_TIF_SECCOMP + beq 1f + mov r0, scno + bl __secure_computing + add r0, sp, #S_R0 + S_OFF @ pointer to regs + ldmia r0, {r0 - r3} @ have to reload r0 - r3 +1: +#endif + + tst r10, #_TIF_SYSCALL_TRACE @ 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 +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 +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 r2, scno + add r1, sp, #S_OFF + mov r0, #0 @ trace entry [IP = 0] + bl syscall_trace + + 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 - 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 +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_fork_wrapper: + add r0, sp, #S_OFF + b sys_fork +ENDPROC(sys_fork_wrapper) + +sys_vfork_wrapper: + add r0, sp, #S_OFF + b sys_vfork +ENDPROC(sys_vfork_wrapper) + +sys_execve_wrapper: + add r3, sp, #S_OFF + b sys_execve +ENDPROC(sys_execve_wrapper) + +sys_clone_wrapper: + add ip, sp, #S_OFF + str ip, [sp, #4] + b sys_clone +ENDPROC(sys_clone_wrapper) + +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_sigaltstack_wrapper: + ldr r2, [sp, #S_OFF + S_SP] + b do_sigaltstack +ENDPROC(sys_sigaltstack_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 + |