412 строки
8.4 KiB
ArmAsm
412 строки
8.4 KiB
ArmAsm
/* $Id: entry.S,v 1.37 2004/06/11 13:02:46 doyu Exp $
|
|
*
|
|
* linux/arch/sh/entry.S
|
|
*
|
|
* Copyright (C) 1999, 2000, 2002 Niibe Yutaka
|
|
* Copyright (C) 2003 Paul Mundt
|
|
*
|
|
* This file is subject to the terms and conditions of the GNU General Public
|
|
* License. See the file "COPYING" in the main directory of this archive
|
|
* for more details.
|
|
*
|
|
*/
|
|
|
|
! NOTE:
|
|
! GNU as (as of 2.9.1) changes bf/s into bt/s and bra, when the address
|
|
! to be jumped is too far, but it causes illegal slot exception.
|
|
|
|
/*
|
|
* entry.S contains the system-call and fault low-level handling routines.
|
|
* This also contains the timer-interrupt handler, as well as all interrupts
|
|
* and faults that can result in a task-switch.
|
|
*
|
|
* NOTE: This code handles signal-recognition, which happens every time
|
|
* after a timer-interrupt and after each system call.
|
|
*
|
|
* NOTE: This code uses a convention that instructions in the delay slot
|
|
* of a transfer-control instruction are indented by an extra space, thus:
|
|
*
|
|
* jmp @k0 ! control-transfer instruction
|
|
* ldc k1, ssr ! delay slot
|
|
*
|
|
* Stack layout in 'ret_from_syscall':
|
|
* ptrace needs to have all regs on the stack.
|
|
* if the order here is changed, it needs to be
|
|
* updated in ptrace.c and ptrace.h
|
|
*
|
|
* r0
|
|
* ...
|
|
* r15 = stack pointer
|
|
* spc
|
|
* pr
|
|
* ssr
|
|
* gbr
|
|
* mach
|
|
* macl
|
|
* syscall #
|
|
*
|
|
*/
|
|
|
|
#if defined(CONFIG_PREEMPT)
|
|
# define preempt_stop() cli
|
|
#else
|
|
# define preempt_stop()
|
|
# define resume_kernel __restore_all
|
|
#endif
|
|
|
|
|
|
.align 2
|
|
ENTRY(exception_error)
|
|
!
|
|
#ifdef CONFIG_TRACE_IRQFLAGS
|
|
mov.l 2f, r0
|
|
jsr @r0
|
|
nop
|
|
#endif
|
|
sti
|
|
mov.l 1f, r0
|
|
jmp @r0
|
|
nop
|
|
|
|
.align 2
|
|
1: .long do_exception_error
|
|
#ifdef CONFIG_TRACE_IRQFLAGS
|
|
2: .long trace_hardirqs_on
|
|
#endif
|
|
|
|
.align 2
|
|
ret_from_exception:
|
|
preempt_stop()
|
|
#ifdef CONFIG_TRACE_IRQFLAGS
|
|
mov.l 4f, r0
|
|
jsr @r0
|
|
nop
|
|
#endif
|
|
ENTRY(ret_from_irq)
|
|
!
|
|
mov #OFF_SR, r0
|
|
mov.l @(r0,r15), r0 ! get status register
|
|
shll r0
|
|
shll r0 ! kernel space?
|
|
get_current_thread_info r8, r0
|
|
bt resume_kernel ! Yes, it's from kernel, go back soon
|
|
|
|
#ifdef CONFIG_PREEMPT
|
|
bra resume_userspace
|
|
nop
|
|
ENTRY(resume_kernel)
|
|
mov.l @(TI_PRE_COUNT,r8), r0 ! current_thread_info->preempt_count
|
|
tst r0, r0
|
|
bf noresched
|
|
need_resched:
|
|
mov.l @(TI_FLAGS,r8), r0 ! current_thread_info->flags
|
|
tst #_TIF_NEED_RESCHED, r0 ! need_resched set?
|
|
bt noresched
|
|
|
|
mov #OFF_SR, r0
|
|
mov.l @(r0,r15), r0 ! get status register
|
|
and #0xf0, r0 ! interrupts off (exception path)?
|
|
cmp/eq #0xf0, r0
|
|
bt noresched
|
|
|
|
mov.l 1f, r0
|
|
mov.l r0, @(TI_PRE_COUNT,r8)
|
|
|
|
#ifdef CONFIG_TRACE_IRQFLAGS
|
|
mov.l 3f, r0
|
|
jsr @r0
|
|
nop
|
|
#endif
|
|
sti
|
|
mov.l 2f, r0
|
|
jsr @r0
|
|
nop
|
|
mov #0, r0
|
|
mov.l r0, @(TI_PRE_COUNT,r8)
|
|
cli
|
|
#ifdef CONFIG_TRACE_IRQFLAGS
|
|
mov.l 4f, r0
|
|
jsr @r0
|
|
nop
|
|
#endif
|
|
|
|
bra need_resched
|
|
nop
|
|
|
|
noresched:
|
|
bra __restore_all
|
|
nop
|
|
|
|
.align 2
|
|
1: .long PREEMPT_ACTIVE
|
|
2: .long schedule
|
|
#ifdef CONFIG_TRACE_IRQFLAGS
|
|
3: .long trace_hardirqs_on
|
|
4: .long trace_hardirqs_off
|
|
#endif
|
|
#endif
|
|
|
|
ENTRY(resume_userspace)
|
|
! r8: current_thread_info
|
|
cli
|
|
#ifdef CONFIG_TRACE_IRQFLAGS
|
|
mov.l 5f, r0
|
|
jsr @r0
|
|
nop
|
|
#endif
|
|
mov.l @(TI_FLAGS,r8), r0 ! current_thread_info->flags
|
|
tst #_TIF_WORK_MASK, r0
|
|
bt/s __restore_all
|
|
tst #_TIF_NEED_RESCHED, r0
|
|
|
|
.align 2
|
|
work_pending:
|
|
! r0: current_thread_info->flags
|
|
! r8: current_thread_info
|
|
! t: result of "tst #_TIF_NEED_RESCHED, r0"
|
|
bf/s work_resched
|
|
tst #(_TIF_SIGPENDING | _TIF_RESTORE_SIGMASK), r0
|
|
work_notifysig:
|
|
bt/s __restore_all
|
|
mov r15, r4
|
|
mov r12, r5 ! set arg1(save_r0)
|
|
mov r0, r6
|
|
mov.l 2f, r1
|
|
mov.l 3f, r0
|
|
jmp @r1
|
|
lds r0, pr
|
|
work_resched:
|
|
#ifndef CONFIG_PREEMPT
|
|
! gUSA handling
|
|
mov.l @(OFF_SP,r15), r0 ! get user space stack pointer
|
|
mov r0, r1
|
|
shll r0
|
|
bf/s 1f
|
|
shll r0
|
|
bf/s 1f
|
|
mov #OFF_PC, r0
|
|
! SP >= 0xc0000000 : gUSA mark
|
|
mov.l @(r0,r15), r2 ! get user space PC (program counter)
|
|
mov.l @(OFF_R0,r15), r3 ! end point
|
|
cmp/hs r3, r2 ! r2 >= r3?
|
|
bt 1f
|
|
add r3, r1 ! rewind point #2
|
|
mov.l r1, @(r0,r15) ! reset PC to rewind point #2
|
|
!
|
|
1:
|
|
#endif
|
|
mov.l 1f, r1
|
|
jsr @r1 ! schedule
|
|
nop
|
|
cli
|
|
#ifdef CONFIG_TRACE_IRQFLAGS
|
|
mov.l 5f, r0
|
|
jsr @r0
|
|
nop
|
|
#endif
|
|
!
|
|
mov.l @(TI_FLAGS,r8), r0 ! current_thread_info->flags
|
|
tst #_TIF_WORK_MASK, r0
|
|
bt __restore_all
|
|
bra work_pending
|
|
tst #_TIF_NEED_RESCHED, r0
|
|
|
|
.align 2
|
|
1: .long schedule
|
|
2: .long do_notify_resume
|
|
3: .long restore_all
|
|
#ifdef CONFIG_TRACE_IRQFLAGS
|
|
4: .long trace_hardirqs_on
|
|
5: .long trace_hardirqs_off
|
|
#endif
|
|
|
|
.align 2
|
|
syscall_exit_work:
|
|
! r0: current_thread_info->flags
|
|
! r8: current_thread_info
|
|
tst #_TIF_SYSCALL_TRACE | _TIF_SINGLESTEP, r0
|
|
bt/s work_pending
|
|
tst #_TIF_NEED_RESCHED, r0
|
|
#ifdef CONFIG_TRACE_IRQFLAGS
|
|
mov.l 5f, r0
|
|
jsr @r0
|
|
nop
|
|
#endif
|
|
sti
|
|
! XXX setup arguments...
|
|
mov.l 4f, r0 ! do_syscall_trace
|
|
jsr @r0
|
|
nop
|
|
bra resume_userspace
|
|
nop
|
|
|
|
.align 2
|
|
syscall_trace_entry:
|
|
! Yes it is traced.
|
|
! XXX setup arguments...
|
|
mov.l 4f, r11 ! Call do_syscall_trace which notifies
|
|
jsr @r11 ! superior (will chomp R[0-7])
|
|
nop
|
|
! Reload R0-R4 from kernel stack, where the
|
|
! parent may have modified them using
|
|
! ptrace(POKEUSR). (Note that R0-R2 are
|
|
! used by the system call handler directly
|
|
! from the kernel stack anyway, so don't need
|
|
! to be reloaded here.) This allows the parent
|
|
! to rewrite system calls and args on the fly.
|
|
mov.l @(OFF_R4,r15), r4 ! arg0
|
|
mov.l @(OFF_R5,r15), r5
|
|
mov.l @(OFF_R6,r15), r6
|
|
mov.l @(OFF_R7,r15), r7 ! arg3
|
|
mov.l @(OFF_R3,r15), r3 ! syscall_nr
|
|
!
|
|
mov.l 2f, r10 ! Number of syscalls
|
|
cmp/hs r10, r3
|
|
bf syscall_call
|
|
mov #-ENOSYS, r0
|
|
bra syscall_exit
|
|
mov.l r0, @(OFF_R0,r15) ! Return value
|
|
|
|
__restore_all:
|
|
mov.l 1f, r0
|
|
jmp @r0
|
|
nop
|
|
|
|
.align 2
|
|
1: .long restore_all
|
|
|
|
.align 2
|
|
syscall_badsys: ! Bad syscall number
|
|
mov #-ENOSYS, r0
|
|
bra resume_userspace
|
|
mov.l r0, @(OFF_R0,r15) ! Return value
|
|
|
|
/*
|
|
* The main debug trap handler.
|
|
*
|
|
* r8=TRA (not the trap number!)
|
|
*
|
|
* Note: This assumes that the trapa value is left in its original
|
|
* form (without the shlr2 shift) so the calculation for the jump
|
|
* call table offset remains a simple in place mask.
|
|
*/
|
|
debug_trap:
|
|
mov r8, r0
|
|
and #(0xf << 2), r0
|
|
mov.l 1f, r8
|
|
add r0, r8
|
|
mov.l @r8, r8
|
|
jmp @r8
|
|
nop
|
|
|
|
.align 2
|
|
1: .long debug_trap_table
|
|
|
|
/*
|
|
* Syscall interface:
|
|
*
|
|
* Syscall #: R3
|
|
* Arguments #0 to #3: R4--R7
|
|
* Arguments #4 to #6: R0, R1, R2
|
|
* TRA: (number of arguments + ABI revision) x 4
|
|
*
|
|
* This code also handles delegating other traps to the BIOS/gdb stub
|
|
* according to:
|
|
*
|
|
* Trap number
|
|
* (TRA>>2) Purpose
|
|
* -------- -------
|
|
* 0x00-0x0f original SH-3/4 syscall ABI (not in general use).
|
|
* 0x10-0x1f general SH-3/4 syscall ABI.
|
|
* 0x20-0x2f syscall ABI for SH-2 parts.
|
|
* 0x30-0x3f debug traps used by the kernel.
|
|
* 0x40-0xff Not supported by all parts, so left unhandled.
|
|
*
|
|
* Note: When we're first called, the TRA value must be shifted
|
|
* right 2 bits in order to get the value that was used as the "trapa"
|
|
* argument.
|
|
*/
|
|
|
|
.align 2
|
|
.globl ret_from_fork
|
|
ret_from_fork:
|
|
mov.l 1f, r8
|
|
jsr @r8
|
|
mov r0, r4
|
|
bra syscall_exit
|
|
nop
|
|
.align 2
|
|
1: .long schedule_tail
|
|
|
|
/*
|
|
* The poorly named main trapa decode and dispatch routine, for
|
|
* system calls and debug traps through their respective jump tables.
|
|
*/
|
|
ENTRY(system_call)
|
|
#if !defined(CONFIG_CPU_SH2)
|
|
mov.l 1f, r9
|
|
mov.l @r9, r8 ! Read from TRA (Trap Address) Register
|
|
#endif
|
|
/*
|
|
* Check the trap type
|
|
*/
|
|
mov #((0x20 << 2) - 1), r9
|
|
cmp/hi r9, r8
|
|
bt/s debug_trap ! it's a debug trap..
|
|
mov #OFF_TRA, r9
|
|
add r15, r9
|
|
mov.l r8, @r9 ! set TRA value to tra
|
|
#ifdef CONFIG_TRACE_IRQFLAGS
|
|
mov.l 5f, r10
|
|
jsr @r10
|
|
nop
|
|
#endif
|
|
sti
|
|
|
|
!
|
|
get_current_thread_info r8, r10
|
|
mov.l @(TI_FLAGS,r8), r8
|
|
mov #_TIF_SYSCALL_TRACE, r10
|
|
tst r10, r8
|
|
bf syscall_trace_entry
|
|
!
|
|
mov.l 2f, r8 ! Number of syscalls
|
|
cmp/hs r8, r3
|
|
bt syscall_badsys
|
|
!
|
|
syscall_call:
|
|
shll2 r3 ! x4
|
|
mov.l 3f, r8 ! Load the address of sys_call_table
|
|
add r8, r3
|
|
mov.l @r3, r8
|
|
jsr @r8 ! jump to specific syscall handler
|
|
nop
|
|
mov.l @(OFF_R0,r15), r12 ! save r0
|
|
mov.l r0, @(OFF_R0,r15) ! save the return value
|
|
!
|
|
syscall_exit:
|
|
cli
|
|
#ifdef CONFIG_TRACE_IRQFLAGS
|
|
mov.l 6f, r0
|
|
jsr @r0
|
|
nop
|
|
#endif
|
|
!
|
|
get_current_thread_info r8, r0
|
|
mov.l @(TI_FLAGS,r8), r0 ! current_thread_info->flags
|
|
tst #_TIF_ALLWORK_MASK, r0
|
|
bf syscall_exit_work
|
|
bra __restore_all
|
|
nop
|
|
.align 2
|
|
#if !defined(CONFIG_CPU_SH2)
|
|
1: .long TRA
|
|
#endif
|
|
2: .long NR_syscalls
|
|
3: .long sys_call_table
|
|
4: .long do_syscall_trace
|
|
#ifdef CONFIG_TRACE_IRQFLAGS
|
|
5: .long trace_hardirqs_on
|
|
6: .long trace_hardirqs_off
|
|
#endif
|