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linux/arch/arm26/kernel/entry.S
Linus Torvalds 1da177e4c3 Linux-2.6.12-rc2 
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
2005-04-16 15:20:36 -07:00

962 lines
24 KiB
ArmAsm
Raw Blame History

/* arch/arm26/kernel/entry.S
*
* Assembled from chunks of code in arch/arm
*
* Copyright (C) 2003 Ian Molton
* Based on the work of RMK.
*
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
#include <asm/asm_offsets.h>
#include <asm/errno.h>
#include <asm/hardware.h>
#include <asm/sysirq.h>
#include <asm/thread_info.h>
#include <asm/page.h>
#include <asm/ptrace.h>
.macro zero_fp
#ifndef CONFIG_NO_FRAME_POINTER
mov fp, #0
#endif
.endm
.text
@ Bad Abort numbers
@ -----------------
@
#define BAD_PREFETCH 0
#define BAD_DATA 1
#define BAD_ADDREXCPTN 2
#define BAD_IRQ 3
#define BAD_UNDEFINSTR 4
@ OS version number used in SWIs
@ RISC OS is 0
@ RISC iX is 8
@
#define OS_NUMBER 9
#define ARMSWI_OFFSET 0x000f0000
@
@ Stack format (ensured by USER_* and SVC_*)
@ PSR and PC are comined on arm26
@
#define S_OFF 8
#define S_OLD_R0 64
#define S_PC 60
#define S_LR 56
#define S_SP 52
#define S_IP 48
#define S_FP 44
#define S_R10 40
#define S_R9 36
#define S_R8 32
#define S_R7 28
#define S_R6 24
#define S_R5 20
#define S_R4 16
#define S_R3 12
#define S_R2 8
#define S_R1 4
#define S_R0 0
.macro save_user_regs
str r0, [sp, #-4]! @ Store SVC r0
str lr, [sp, #-4]! @ Store user mode PC
sub sp, sp, #15*4
stmia sp, {r0 - lr}^ @ Store the other user-mode regs
mov r0, r0
.endm
.macro slow_restore_user_regs
ldmia sp, {r0 - lr}^ @ restore the user regs not including PC
mov r0, r0
ldr lr, [sp, #15*4] @ get user PC
add sp, sp, #15*4+8 @ free stack
movs pc, lr @ return
.endm
.macro fast_restore_user_regs
add sp, sp, #S_OFF
ldmib sp, {r1 - lr}^
mov r0, r0
ldr lr, [sp, #15*4]
add sp, sp, #15*4+8
movs pc, lr
.endm
.macro save_svc_regs
str sp, [sp, #-16]!
str lr, [sp, #8]
str lr, [sp, #4]
stmfd sp!, {r0 - r12}
mov r0, #-1
str r0, [sp, #S_OLD_R0]
zero_fp
.endm
.macro save_svc_regs_irq
str sp, [sp, #-16]!
str lr, [sp, #4]
ldr lr, .LCirq
ldr lr, [lr]
str lr, [sp, #8]
stmfd sp!, {r0 - r12}
mov r0, #-1
str r0, [sp, #S_OLD_R0]
zero_fp
.endm
.macro restore_svc_regs
ldmfd sp, {r0 - pc}^
.endm
.macro mask_pc, rd, rm
bic \rd, \rm, #PCMASK
.endm
.macro disable_irqs, temp
mov \temp, pc
orr \temp, \temp, #PSR_I_BIT
teqp \temp, #0
.endm
.macro enable_irqs, temp
mov \temp, pc
and \temp, \temp, #~PSR_I_BIT
teqp \temp, #0
.endm
.macro initialise_traps_extra
.endm
.macro get_thread_info, rd
mov \rd, sp, lsr #13
mov \rd, \rd, lsl #13
.endm
/*
* These are the registers used in the syscall handler, and allow us to
* have in theory up to 7 arguments to a function - r0 to r6.
*
* Note that tbl == why is intentional.
*
* We must set at least "tsk" and "why" when calling ret_with_reschedule.
*/
scno .req r7 @ syscall number
tbl .req r8 @ syscall table pointer
why .req r8 @ Linux syscall (!= 0)
tsk .req r9 @ current thread_info
/*
* Get the system call number.
*/
.macro get_scno
mask_pc lr, lr
ldr scno, [lr, #-4] @ get SWI instruction
.endm
/*
* -----------------------------------------------------------------------
*/
/*
* We rely on the fact that R0 is at the bottom of the stack (due to
* slow/fast restore user regs).
*/
#if S_R0 != 0
#error "Please fix"
#endif
/*
* 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:
disable_irqs r1 @ disable interrupts
ldr r1, [tsk, #TI_FLAGS]
tst r1, #_TIF_WORK_MASK
bne fast_work_pending
fast_restore_user_regs
/*
* 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_NOTIFY_RESUME | _TIF_SIGPENDING
beq no_work_pending
mov r0, sp @ 'regs'
mov r2, why @ 'syscall'
bl do_notify_resume
disable_irqs r1 @ disable interrupts
b no_work_pending
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_irqs r1 @ disable interrupts
ldr r1, [tsk, #TI_FLAGS]
tst r1, #_TIF_WORK_MASK
bne work_pending
no_work_pending:
slow_restore_user_regs
/*
* 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
// FIXME - is this strictly necessary?
#include "calls.S"
/*=============================================================================
* SWI handler
*-----------------------------------------------------------------------------
*/
.align 5
ENTRY(vector_swi)
save_user_regs
zero_fp
get_scno
#ifdef CONFIG_ALIGNMENT_TRAP
ldr ip, __cr_alignment
ldr ip, [ip]
mcr p15, 0, ip, c1, c0 @ update control register
#endif
enable_irqs ip
str r4, [sp, #-S_OFF]! @ push fifth arg
get_thread_info tsk
ldr ip, [tsk, #TI_FLAGS] @ check for syscall tracing
bic scno, scno, #0xff000000 @ mask off SWI op-code
eor scno, scno, #OS_NUMBER << 20 @ check OS number
adr tbl, sys_call_table @ load syscall table pointer
tst ip, #_TIF_SYSCALL_TRACE @ are we tracing syscalls?
bne __sys_trace
adral lr, ret_fast_syscall @ set return address
orral lr, lr, #PSR_I_BIT | MODE_SVC26 @ Force SVC mode on return
cmp scno, #NR_syscalls @ check upper syscall limit
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, #ARMSWI_OFFSET
eor r0, scno, #OS_NUMBER << 20 @ put OS number back
bcs arm_syscall
b sys_ni_syscall @ not private func
/*
* This is the really slow path. We're going to be doing
* context switches, and waiting for our parent to respond.
*/
__sys_trace:
add r1, sp, #S_OFF
mov r0, #0 @ trace entry [IP = 0]
bl syscall_trace
adral lr, __sys_trace_return @ set return address
orral lr, lr, #PSR_I_BIT | MODE_SVC26 @ Force SVC mode on return
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 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
.type sys_call_table, #object
ENTRY(sys_call_table)
#include "calls.S"
/*============================================================================
* Special system call wrappers
*/
@ r0 = syscall number
@ r5 = syscall table
.type sys_syscall, #function
sys_syscall:
eor scno, r0, #OS_NUMBER << 20
cmp scno, #NR_syscalls @ check range
stmleia sp, {r5, r6} @ shuffle args
movle r0, r1
movle r1, r2
movle r2, r3
movle r3, r4
ldrle pc, [tbl, scno, lsl #2]
b sys_ni_syscall
sys_fork_wrapper:
add r0, sp, #S_OFF
b sys_fork
sys_vfork_wrapper:
add r0, sp, #S_OFF
b sys_vfork
sys_execve_wrapper:
add r3, sp, #S_OFF
b sys_execve
sys_clone_wapper:
add r2, sp, #S_OFF
b sys_clone
sys_sigsuspend_wrapper:
add r3, sp, #S_OFF
b sys_sigsuspend
sys_rt_sigsuspend_wrapper:
add r2, sp, #S_OFF
b sys_rt_sigsuspend
sys_sigreturn_wrapper:
add r0, sp, #S_OFF
b sys_sigreturn
sys_rt_sigreturn_wrapper:
add r0, sp, #S_OFF
b sys_rt_sigreturn
sys_sigaltstack_wrapper:
ldr r2, [sp, #S_OFF + S_SP]
b do_sigaltstack
/*
* Note: off_4k (r5) is always units of 4K. If we can't do the requested
* offset, we return EINVAL. FIXME - this lost some stuff from arm32 to
* ifdefs. check it out.
*/
sys_mmap2:
tst r5, #((1 << (PAGE_SHIFT - 12)) - 1)
moveq r5, r5, lsr #PAGE_SHIFT - 12
streq r5, [sp, #4]
beq do_mmap2
mov r0, #-EINVAL
RETINSTR(mov,pc, lr)
/*
* Design issues:
* - We have several modes that each vector can be called from,
* each with its own set of registers. On entry to any vector,
* we *must* save the registers used in *that* mode.
*
* - This code must be as fast as possible.
*
* There are a few restrictions on the vectors:
* - the SWI vector cannot be called from *any* non-user mode
*
* - the FP emulator is *never* called from *any* non-user mode undefined
* instruction.
*
*/
.text
.macro handle_irq
1: mov r4, #IOC_BASE
ldrb r6, [r4, #0x24] @ get high priority first
adr r5, irq_prio_h
teq r6, #0
ldreqb r6, [r4, #0x14] @ get low priority
adreq r5, irq_prio_l
teq r6, #0 @ If an IRQ happened...
ldrneb r0, [r5, r6] @ get IRQ number
movne r1, sp @ get struct pt_regs
adrne lr, 1b @ Set return address to 1b
orrne lr, lr, #PSR_I_BIT | MODE_SVC26 @ (and force SVC mode)
bne asm_do_IRQ @ process IRQ (if asserted)
.endm
/*
* Interrupt table (incorporates priority)
*/
.macro irq_prio_table
irq_prio_l: .byte 0, 0, 1, 0, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3
.byte 4, 0, 1, 0, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3
.byte 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5
.byte 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5
.byte 6, 6, 6, 6, 6, 6, 6, 6, 3, 3, 3, 3, 3, 3, 3, 3
.byte 6, 6, 6, 6, 6, 6, 6, 6, 3, 3, 3, 3, 3, 3, 3, 3
.byte 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5
.byte 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5
.byte 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7
.byte 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7
.byte 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7
.byte 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7
.byte 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7
.byte 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7
.byte 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7
.byte 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7
irq_prio_h: .byte 0, 8, 9, 8,10,10,10,10,11,11,11,11,10,10,10,10
.byte 12, 8, 9, 8,10,10,10,10,11,11,11,11,10,10,10,10
.byte 13,13,13,13,10,10,10,10,11,11,11,11,10,10,10,10
.byte 13,13,13,13,10,10,10,10,11,11,11,11,10,10,10,10
.byte 14,14,14,14,10,10,10,10,11,11,11,11,10,10,10,10
.byte 14,14,14,14,10,10,10,10,11,11,11,11,10,10,10,10
.byte 13,13,13,13,10,10,10,10,11,11,11,11,10,10,10,10
.byte 13,13,13,13,10,10,10,10,11,11,11,11,10,10,10,10
.byte 15,15,15,15,10,10,10,10,11,11,11,11,10,10,10,10
.byte 15,15,15,15,10,10,10,10,11,11,11,11,10,10,10,10
.byte 13,13,13,13,10,10,10,10,11,11,11,11,10,10,10,10
.byte 13,13,13,13,10,10,10,10,11,11,11,11,10,10,10,10
.byte 15,15,15,15,10,10,10,10,11,11,11,11,10,10,10,10
.byte 15,15,15,15,10,10,10,10,11,11,11,11,10,10,10,10
.byte 13,13,13,13,10,10,10,10,11,11,11,11,10,10,10,10
.byte 13,13,13,13,10,10,10,10,11,11,11,11,10,10,10,10
.endm
#if 1
/*
* Uncomment these if you wish to get more debugging into about data aborts.
* FIXME - I bet we can find a way to encode these and keep performance.
*/
#define FAULT_CODE_LDRSTRPOST 0x80
#define FAULT_CODE_LDRSTRPRE 0x40
#define FAULT_CODE_LDRSTRREG 0x20
#define FAULT_CODE_LDMSTM 0x10
#define FAULT_CODE_LDCSTC 0x08
#endif
#define FAULT_CODE_PREFETCH 0x04
#define FAULT_CODE_WRITE 0x02
#define FAULT_CODE_FORCECOW 0x01
/*=============================================================================
* Undefined FIQs
*-----------------------------------------------------------------------------
*/
_unexp_fiq: ldr sp, .LCfiq
mov r12, #IOC_BASE
strb r12, [r12, #0x38] @ Disable FIQ register
teqp pc, #PSR_I_BIT | PSR_F_BIT | MODE_SVC26
mov r0, r0
stmfd sp!, {r0 - r3, ip, lr}
adr r0, Lfiqmsg
bl printk
ldmfd sp!, {r0 - r3, ip, lr}
teqp pc, #PSR_I_BIT | PSR_F_BIT | MODE_FIQ26
mov r0, r0
movs pc, lr
Lfiqmsg: .ascii "*** Unexpected FIQ\n\0"
.align
.LCfiq: .word __temp_fiq
.LCirq: .word __temp_irq
/*=============================================================================
* Undefined instruction handler
*-----------------------------------------------------------------------------
* Handles floating point instructions
*/
vector_undefinstr:
tst lr, #MODE_SVC26 @ did we come from a non-user mode?
bne __und_svc @ yes - deal with it.
/* Otherwise, fall through for the user-space (common) case. */
save_user_regs
zero_fp @ zero frame pointer
teqp pc, #PSR_I_BIT | MODE_SVC26 @ disable IRQs
.Lbug_undef:
ldr r4, .LC2
ldr pc, [r4] @ Call FP module entry point
/* FIXME - should we trap for a null pointer here? */
/* The SVC mode case */
__und_svc: save_svc_regs @ Non-user mode
mask_pc r0, lr
and r2, lr, #3
sub r0, r0, #4
mov r1, sp
bl do_undefinstr
restore_svc_regs
/* We get here if the FP emulator doesnt handle the undef instr.
* If the insn WAS handled, the emulator jumps to ret_from_exception by itself/
*/
.globl fpundefinstr
fpundefinstr:
mov r0, lr
mov r1, sp
teqp pc, #MODE_SVC26
bl do_undefinstr
b ret_from_exception @ Normal FP exit
#if defined CONFIG_FPE_NWFPE || defined CONFIG_FPE_FASTFPE
/* The FPE is always present */
.equ fpe_not_present, 0
#else
/* We get here if an undefined instruction happens and the floating
* point emulator is not present. If the offending instruction was
* a WFS, we just perform a normal return as if we had emulated the
* operation. This is a hack to allow some basic userland binaries
* to run so that the emulator module proper can be loaded. --philb
* FIXME - probably a broken useless hack...
*/
fpe_not_present:
adr r10, wfs_mask_data
ldmia r10, {r4, r5, r6, r7, r8}
ldr r10, [sp, #S_PC] @ Load PC
sub r10, r10, #4
mask_pc r10, r10
ldrt r10, [r10] @ get instruction
and r5, r10, r5
teq r5, r4 @ Is it WFS?
beq ret_from_exception
and r5, r10, r8
teq r5, r6 @ Is it LDF/STF on sp or fp?
teqne r5, r7
bne fpundefinstr
tst r10, #0x00200000 @ Does it have WB
beq ret_from_exception
and r4, r10, #255 @ get offset
and r6, r10, #0x000f0000
tst r10, #0x00800000 @ +/-
ldr r5, [sp, r6, lsr #14] @ Load reg
rsbeq r4, r4, #0
add r5, r5, r4, lsl #2
str r5, [sp, r6, lsr #14] @ Save reg
b ret_from_exception
wfs_mask_data: .word 0x0e200110 @ WFS/RFS
.word 0x0fef0fff
.word 0x0d0d0100 @ LDF [sp]/STF [sp]
.word 0x0d0b0100 @ LDF [fp]/STF [fp]
.word 0x0f0f0f00
#endif
.LC2: .word fp_enter
/*=============================================================================
* Prefetch abort handler
*-----------------------------------------------------------------------------
*/
#define DEBUG_UNDEF
/* remember: lr = USR pc */
vector_prefetch:
sub lr, lr, #4
tst lr, #MODE_SVC26
bne __pabt_invalid
save_user_regs
teqp pc, #MODE_SVC26 @ Enable IRQs...
mask_pc r0, lr @ Address of abort
mov r1, sp @ Tasks registers
bl do_PrefetchAbort
teq r0, #0 @ If non-zero, we believe this abort..
bne ret_from_exception
#ifdef DEBUG_UNDEF
adr r0, t
bl printk
#endif
ldr lr, [sp,#S_PC] @ FIXME program to test this on. I think its
b .Lbug_undef @ broken at the moment though!)
__pabt_invalid: save_svc_regs
mov r0, sp @ Prefetch aborts are definitely *not*
mov r1, #BAD_PREFETCH @ allowed in non-user modes. We cant
and r2, lr, #3 @ recover from this problem.
b bad_mode
#ifdef DEBUG_UNDEF
t: .ascii "*** undef ***\r\n\0"
.align
#endif
/*=============================================================================
* Address exception handler
*-----------------------------------------------------------------------------
* These aren't too critical.
* (they're not supposed to happen).
* In order to debug the reason for address exceptions in non-user modes,
* we have to obtain all the registers so that we can see what's going on.
*/
vector_addrexcptn:
sub lr, lr, #8
tst lr, #3
bne Laddrexcptn_not_user
save_user_regs
teq pc, #MODE_SVC26
mask_pc r0, lr @ Point to instruction
mov r1, sp @ Point to registers
mov r2, #0x400
mov lr, pc
bl do_excpt
b ret_from_exception
Laddrexcptn_not_user:
save_svc_regs
and r2, lr, #3
teq r2, #3
bne Laddrexcptn_illegal_mode
teqp pc, #MODE_SVC26
mask_pc r0, lr
mov r1, sp
orr r2, r2, #0x400
bl do_excpt
ldmia sp, {r0 - lr} @ I cant remember the reason I changed this...
add sp, sp, #15*4
movs pc, lr
Laddrexcptn_illegal_mode:
mov r0, sp
str lr, [sp, #-4]!
orr r1, r2, #PSR_I_BIT | PSR_F_BIT
teqp r1, #0 @ change into mode (wont be user mode)
mov r0, r0
mov r1, r8 @ Any register from r8 - r14 can be banked
mov r2, r9
mov r3, r10
mov r4, r11
mov r5, r12
mov r6, r13
mov r7, r14
teqp pc, #PSR_F_BIT | MODE_SVC26 @ back to svc
mov r0, r0
stmfd sp!, {r1-r7}
ldmia r0, {r0-r7}
stmfd sp!, {r0-r7}
mov r0, sp
mov r1, #BAD_ADDREXCPTN
b bad_mode
/*=============================================================================
* Interrupt (IRQ) handler
*-----------------------------------------------------------------------------
* Note: if the IRQ was taken whilst in user mode, then *no* kernel routine
* is running, so do not have to save svc lr.
*
* Entered in IRQ mode.
*/
vector_IRQ: ldr sp, .LCirq @ Setup some temporary stack
sub lr, lr, #4
str lr, [sp] @ push return address
tst lr, #3
bne __irq_non_usr
__irq_usr: teqp pc, #PSR_I_BIT | MODE_SVC26 @ Enter SVC mode
mov r0, r0
ldr lr, .LCirq
ldr lr, [lr] @ Restore lr for jump back to USR
save_user_regs
handle_irq
mov why, #0
get_thread_info tsk
b ret_to_user
@ Place the IRQ priority table here so that the handle_irq macros above
@ and below here can access it.
irq_prio_table
__irq_non_usr: teqp pc, #PSR_I_BIT | MODE_SVC26 @ Enter SVC mode
mov r0, r0
save_svc_regs_irq
and r2, lr, #3
teq r2, #3
bne __irq_invalid @ IRQ not from SVC mode
handle_irq
restore_svc_regs
__irq_invalid: mov r0, sp
mov r1, #BAD_IRQ
b bad_mode
/*=============================================================================
* Data abort handler code
*-----------------------------------------------------------------------------
*
* This handles both exceptions from user and SVC modes, computes the address
* range of the problem, and does any correction that is required. It then
* calls the kernel data abort routine.
*
* This is where I wish that the ARM would tell you which address aborted.
*/
vector_data: sub lr, lr, #8 @ Correct lr
tst lr, #3
bne Ldata_not_user
save_user_regs
teqp pc, #MODE_SVC26
mask_pc r0, lr
bl Ldata_do
b ret_from_exception
Ldata_not_user:
save_svc_regs
and r2, lr, #3
teq r2, #3
bne Ldata_illegal_mode
tst lr, #PSR_I_BIT
teqeqp pc, #MODE_SVC26
mask_pc r0, lr
bl Ldata_do
restore_svc_regs
Ldata_illegal_mode:
mov r0, sp
mov r1, #BAD_DATA
b bad_mode
Ldata_do: mov r3, sp
ldr r4, [r0] @ Get instruction
mov r2, #0
tst r4, #1 << 20 @ Check to see if it is a write instruction
orreq r2, r2, #FAULT_CODE_WRITE @ Indicate write instruction
mov r1, r4, lsr #22 @ Now branch to the relevent processing routine
and r1, r1, #15 << 2
add pc, pc, r1
movs pc, lr
b Ldata_unknown
b Ldata_unknown
b Ldata_unknown
b Ldata_unknown
b Ldata_ldrstr_post @ ldr rd, [rn], #m
b Ldata_ldrstr_numindex @ ldr rd, [rn, #m] @ RegVal
b Ldata_ldrstr_post @ ldr rd, [rn], rm
b Ldata_ldrstr_regindex @ ldr rd, [rn, rm]
b Ldata_ldmstm @ ldm*a rn, <rlist>
b Ldata_ldmstm @ ldm*b rn, <rlist>
b Ldata_unknown
b Ldata_unknown
b Ldata_ldrstr_post @ ldc rd, [rn], #m @ Same as ldr rd, [rn], #m
b Ldata_ldcstc_pre @ ldc rd, [rn, #m]
b Ldata_unknown
Ldata_unknown: @ Part of jumptable
mov r0, r1
mov r1, r4
mov r2, r3
b baddataabort
Ldata_ldrstr_post:
mov r0, r4, lsr #14 @ Get Rn
and r0, r0, #15 << 2 @ Mask out reg.
teq r0, #15 << 2
ldr r0, [r3, r0] @ Get register
biceq r0, r0, #PCMASK
mov r1, r0
#ifdef FAULT_CODE_LDRSTRPOST
orr r2, r2, #FAULT_CODE_LDRSTRPOST
#endif
b do_DataAbort
Ldata_ldrstr_numindex:
mov r0, r4, lsr #14 @ Get Rn
and r0, r0, #15 << 2 @ Mask out reg.
teq r0, #15 << 2
ldr r0, [r3, r0] @ Get register
mov r1, r4, lsl #20
biceq r0, r0, #PCMASK
tst r4, #1 << 23
addne r0, r0, r1, lsr #20
subeq r0, r0, r1, lsr #20
mov r1, r0
#ifdef FAULT_CODE_LDRSTRPRE
orr r2, r2, #FAULT_CODE_LDRSTRPRE
#endif
b do_DataAbort
Ldata_ldrstr_regindex:
mov r0, r4, lsr #14 @ Get Rn
and r0, r0, #15 << 2 @ Mask out reg.
teq r0, #15 << 2
ldr r0, [r3, r0] @ Get register
and r7, r4, #15
biceq r0, r0, #PCMASK
teq r7, #15 @ Check for PC
ldr r7, [r3, r7, lsl #2] @ Get Rm
and r8, r4, #0x60 @ Get shift types
biceq r7, r7, #PCMASK
mov r9, r4, lsr #7 @ Get shift amount
and r9, r9, #31
teq r8, #0
moveq r7, r7, lsl r9
teq r8, #0x20 @ LSR shift
moveq r7, r7, lsr r9
teq r8, #0x40 @ ASR shift
moveq r7, r7, asr r9
teq r8, #0x60 @ ROR shift
moveq r7, r7, ror r9
tst r4, #1 << 23
addne r0, r0, r7
subeq r0, r0, r7 @ Apply correction
mov r1, r0
#ifdef FAULT_CODE_LDRSTRREG
orr r2, r2, #FAULT_CODE_LDRSTRREG
#endif
b do_DataAbort
Ldata_ldmstm:
mov r7, #0x11
orr r7, r7, r7, lsl #8
and r0, r4, r7
and r1, r4, r7, lsl #1
add r0, r0, r1, lsr #1
and r1, r4, r7, lsl #2
add r0, r0, r1, lsr #2
and r1, r4, r7, lsl #3
add r0, r0, r1, lsr #3
add r0, r0, r0, lsr #8
add r0, r0, r0, lsr #4
and r7, r0, #15 @ r7 = no. of registers to transfer.
mov r5, r4, lsr #14 @ Get Rn
and r5, r5, #15 << 2
ldr r0, [r3, r5] @ Get reg
eor r6, r4, r4, lsl #2
tst r6, #1 << 23 @ Check inc/dec ^ writeback
rsbeq r7, r7, #0
add r7, r0, r7, lsl #2 @ Do correction (signed)
subne r1, r7, #1
subeq r1, r0, #1
moveq r0, r7
tst r4, #1 << 21 @ Check writeback
strne r7, [r3, r5]
eor r6, r4, r4, lsl #1
tst r6, #1 << 24 @ Check Pre/Post ^ inc/dec
addeq r0, r0, #4
addeq r1, r1, #4
teq r5, #15*4 @ CHECK FOR PC
biceq r1, r1, #PCMASK
biceq r0, r0, #PCMASK
#ifdef FAULT_CODE_LDMSTM
orr r2, r2, #FAULT_CODE_LDMSTM
#endif
b do_DataAbort
Ldata_ldcstc_pre:
mov r0, r4, lsr #14 @ Get Rn
and r0, r0, #15 << 2 @ Mask out reg.
teq r0, #15 << 2
ldr r0, [r3, r0] @ Get register
mov r1, r4, lsl #24 @ Get offset
biceq r0, r0, #PCMASK
tst r4, #1 << 23
addne r0, r0, r1, lsr #24
subeq r0, r0, r1, lsr #24
mov r1, r0
#ifdef FAULT_CODE_LDCSTC
orr r2, r2, #FAULT_CODE_LDCSTC
#endif
b do_DataAbort
/*
* This is the return code to user mode for abort handlers
*/
ENTRY(ret_from_exception)
get_thread_info tsk
mov why, #0
b ret_to_user
.data
ENTRY(fp_enter)
.word fpe_not_present
.text
/*
* Register switch for older 26-bit only ARMs
*/
ENTRY(__switch_to)
add r0, r0, #TI_CPU_SAVE
stmia r0, {r4 - sl, fp, sp, lr}
add r1, r1, #TI_CPU_SAVE
ldmia r1, {r4 - sl, fp, sp, pc}^
/*
*=============================================================================
* Low-level interface code
*-----------------------------------------------------------------------------
* Trap initialisation
*-----------------------------------------------------------------------------
*
* Note - FIQ code has changed. The default is a couple of words in 0x1c, 0x20
* that call _unexp_fiq. Nowever, we now copy the FIQ routine to 0x1c (removes
* some excess cycles).
*
* What we need to put into 0-0x1c are branches to branch to the kernel.
*/
.section ".init.text",#alloc,#execinstr
.Ljump_addresses:
swi SYS_ERROR0
.word vector_undefinstr - 12
.word vector_swi - 16
.word vector_prefetch - 20
.word vector_data - 24
.word vector_addrexcptn - 28
.word vector_IRQ - 32
.word _unexp_fiq - 36
b . + 8
/*
* initialise the trap system
*/
ENTRY(__trap_init)
stmfd sp!, {r4 - r7, lr}
adr r1, .Ljump_addresses
ldmia r1, {r1 - r7, ip, lr}
orr r2, lr, r2, lsr #2
orr r3, lr, r3, lsr #2
orr r4, lr, r4, lsr #2
orr r5, lr, r5, lsr #2
orr r6, lr, r6, lsr #2
orr r7, lr, r7, lsr #2
orr ip, lr, ip, lsr #2
mov r0, #0
stmia r0, {r1 - r7, ip}
ldmfd sp!, {r4 - r7, pc}^
.bss
__temp_irq: .space 4 @ saved lr_irq
__temp_fiq: .space 128
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