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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /arch/arm/kernel/entry-common.S
Initial import
Diffstat (limited to 'arch/arm/kernel/entry-common.S')
-rw-r--r--arch/arm/kernel/entry-common.S388
1 files changed, 388 insertions, 0 deletions
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
new file mode 100644
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+/*
+ * 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/assembler.h>
+#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] @ re-check for syscall tracing
+ tst r1, #_TIF_SYSCALL_WORK
+ bne __sys_trace_return
+ 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)
+ retne 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
+
+/*=============================================================================
+ * 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
+ alignment_trap r10, ip, __cr_alignment
+ 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
+ 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 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
+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, 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
+ ret 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
+