entry-armv.s

Linux内核源代码 为压缩文件 是<<Linux内核>>一书中的源代码

		stmia	sp, {r0 - lr}			@ Save SVC r0 - lr [lr *should* be intact]
		ldr	r4, .LCabt
		mov	r1, #BAD_DATA
		b	1f

__irq_invalid:	sub	sp, sp, #S_FRAME_SIZE		@ Allocate space on stack for frame
		stmfd	sp, {r0 - lr}			@ Save r0 - lr
		ldr	r4, .LCirq
		mov	r1, #BAD_IRQ
		b	1f

__und_invalid:	sub	sp, sp, #S_FRAME_SIZE
		stmia	sp, {r0 - lr}
		ldr	r4, .LCund
		mov	r1, #BAD_UNDEFINSTR		@ int reason

1:		zero_fp
		ldmia	r4, {r5 - r7}			@ Get XXX pc, cpsr, old_r0
		add	r4, sp, #S_PC
		stmia	r4, {r5 - r7}			@ Save XXX pc, cpsr, old_r0
		mov	r0, sp
		and	r2, r6, #31			@ int mode
		b	SYMBOL_NAME(bad_mode)

#ifdef CONFIG_NWFPE
		/* The FPE is always present */
		.equ	fpe_not_present, 0
#else
wfs_mask_data:	.word	0x0e200110			@ WFS/RFS
		.word	0x0fef0fff
		.word	0x0d0d0100			@ LDF [sp]/STF [sp]
		.word	0x0d0b0100			@ LDF [fp]/STF [fp]
		.word	0x0f0f0f00

/* 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
 */
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?
		moveq	pc, r9
		and	r5, r10, r8
		teq	r5, r6				@ Is it LDF/STF on sp or fp?
		teqne	r5, r7
		movne	pc, lr
		tst	r10, #0x00200000		@ Does it have WB
		moveq	pc, r9
		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
		mov	pc, r9
#endif

/*
 * SVC mode handlers
 */
		.align	5
__dabt_svc:	sub	sp, sp, #S_FRAME_SIZE
		stmia	sp, {r0 - r12}			@ save r0 - r12
		ldr	r2, .LCabt
		add	r0, sp, #S_FRAME_SIZE
		ldmia	r2, {r2 - r4}			@ get pc, cpsr
		add	r5, sp, #S_SP
		mov	r1, lr
		stmia	r5, {r0 - r4}			@ save sp_SVC, lr_SVC, pc, cpsr, old_ro
		mrs	r9, cpsr			@ Enable interrupts if they were
		tst	r3, #I_BIT
		biceq	r9, r9, #I_BIT			@ previously
		mov	r0, r2
/*
 * This routine must not corrupt r9
 */
#ifdef MULTI_CPU
		ldr	r2, .LCprocfns
		mov	lr, pc
		ldr	pc, [r2]			@ call processor specific code
#else
		bl	cpu_data_abort
#endif
		msr	cpsr_c, r9
		mov	r2, sp
		bl	SYMBOL_NAME(do_DataAbort)
		mov	r0, #I_BIT | MODE_SVC
		msr	cpsr_c, r0
		ldr	r0, [sp, #S_PSR]
		msr	spsr, r0
		ldmia	sp, {r0 - pc}^			@ load r0 - pc, cpsr

		.align	5
__irq_svc:	sub	sp, sp, #S_FRAME_SIZE
		stmia	sp, {r0 - r12}			@ save r0 - r12
		ldr	r7, .LCirq
		add	r5, sp, #S_FRAME_SIZE
		ldmia	r7, {r7 - r9}
		add	r4, sp, #S_SP
		mov	r6, lr
		stmia	r4, {r5, r6, r7, r8, r9}	@ save sp_SVC, lr_SVC, pc, cpsr, old_ro
1:		get_irqnr_and_base r0, r6, r5, lr
		movne	r1, sp
		@
		@ routine called with r0 = irq number, r1 = struct pt_regs *
		@
		adrsvc	ne, lr, 1b
		bne	do_IRQ
		ldr	r0, [sp, #S_PSR]		@ irqs are already disabled
		msr	spsr, r0
		ldmia	sp, {r0 - pc}^			@ load r0 - pc, cpsr

		.align	5
__und_svc:	sub	sp, sp, #S_FRAME_SIZE
		stmia	sp, {r0 - r12}			@ save r0 - r12
		ldr	r7, .LCund
		mov	r6, lr
		ldmia	r7, {r7 - r9}
		add	r5, sp, #S_FRAME_SIZE
		add	r4, sp, #S_SP
		stmia	r4, {r5 - r9}			@ save sp_SVC, lr_SVC, pc, cpsr, old_ro

		adrsvc	al, r9, 1f			@ r9  = normal FP return
		bl	call_fpe			@ lr  = undefined instr return

		mov	r0, r5				@ unsigned long pc
		mov	r1, sp				@ struct pt_regs *regs
		bl	SYMBOL_NAME(do_undefinstr)

1:		mov	r0, #I_BIT | MODE_SVC
		msr	cpsr_c, r0
		ldr	lr, [sp, #S_PSR]		@ Get SVC cpsr
		msr	spsr, lr
		ldmia	sp, {r0 - pc}^			@ Restore SVC registers

		.align	5
__pabt_svc:	sub	sp, sp, #S_FRAME_SIZE
		stmia	sp, {r0 - r12}			@ save r0 - r12
		ldr	r2, .LCabt
		add	r0, sp, #S_FRAME_SIZE
		ldmia	r2, {r2 - r4}			@ get pc, cpsr
		add	r5, sp, #S_SP
		mov	r1, lr
		stmia	r5, {r0 - r4}			@ save sp_SVC, lr_SVC, pc, cpsr, old_ro
		mrs	r9, cpsr			@ Enable interrupts if they were
		tst	r3, #I_BIT
		biceq	r9, r9, #I_BIT			@ previously
		msr	cpsr_c, r9
		mov	r0, r2				@ address (pc)
		mov	r1, sp				@ regs
		bl	SYMBOL_NAME(do_PrefetchAbort)	@ call abort handler
		mov	r0, #I_BIT | MODE_SVC
		msr	cpsr_c, r0
		ldr	r0, [sp, #S_PSR]
		msr	spsr, r0
		ldmia	sp, {r0 - pc}^			@ load r0 - pc, cpsr

		.align	5
.LCirq:		.word	__temp_irq
.LCund:		.word	__temp_und
.LCabt:		.word	__temp_abt
#ifdef MULTI_CPU
.LCprocfns:	.word	SYMBOL_NAME(processor)
#endif
.LCfp:		.word	SYMBOL_NAME(fp_enter)
#ifdef CONFIG_ALIGNMENT_TRAP
.LCswi:		.word	SYMBOL_NAME(cr_alignment)
#endif

		irq_prio_table

/*
 * User mode handlers
 */
		.align	5
__dabt_usr:	sub	sp, sp, #S_FRAME_SIZE		@ Allocate frame size in one go
		stmia	sp, {r0 - r12}			@ save r0 - r12
		ldr	r4, .LCabt
		add	r3, sp, #S_PC
		ldmia	r4, {r0 - r2}			@ Get USR pc, cpsr
		stmia	r3, {r0 - r2}			@ Save USR pc, cpsr, old_r0
		stmdb	r3, {sp, lr}^
		alignment_trap r4, r7, __temp_abt
		zero_fp
#ifdef MULTI_CPU
		ldr	r2, .LCprocfns
		mov	lr, pc
		ldr	pc, [r2]			@ call processor specific code
#else
		bl	cpu_data_abort
#endif
		mov	r2, #MODE_SVC
		msr	cpsr_c, r2			@ Enable interrupts
		mov	r2, sp
		adrsvc	al, lr, ret_from_sys_call
		b	SYMBOL_NAME(do_DataAbort)

		.align	5
__irq_usr:	sub	sp, sp, #S_FRAME_SIZE
		stmia	sp, {r0 - r12}			@ save r0 - r12
		ldr	r4, .LCirq
		add	r8, sp, #S_PC
		ldmia	r4, {r5 - r7}			@ get saved PC, SPSR
		stmia	r8, {r5 - r7}			@ save pc, psr, old_r0
		stmdb	r8, {sp, lr}^
		alignment_trap r4, r7, __temp_irq
		zero_fp
1:		get_irqnr_and_base r0, r6, r5, lr
		movne	r1, sp
		adrsvc	ne, lr, 1b
		@
		@ routine called with r0 = irq number, r1 = struct pt_regs *
		@
		bne	do_IRQ
		mov	r4, #0
		get_current_task r5
		b	ret_with_reschedule

		.align	5
__und_usr:	sub	sp, sp, #S_FRAME_SIZE		@ Allocate frame size in one go
		stmia	sp, {r0 - r12}			@ Save r0 - r12
		ldr	r4, .LCund
		add	r8, sp, #S_PC
		ldmia	r4, {r5 - r7}
		stmia	r8, {r5 - r7}			@ Save USR pc, cpsr, old_r0
		stmdb	r8, {sp, lr}^			@ Save user sp, lr
		alignment_trap r4, r7, __temp_und
		zero_fp
		adrsvc	al, r9, ret_from_sys_call	@ r9  = normal FP return
		adrsvc	al, lr, fpundefinstr		@ lr  = undefined instr return

call_fpe:	get_current_task r10
		mov	r8, #1
		strb	r8, [r10, #TSK_USED_MATH]	@ set current->used_math
		ldr	r4, .LCfp
		add	r10, r10, #TSS_FPESAVE		@ r10 = workspace
		ldr	pc, [r4]			@ Call FP module USR entry point

fpundefinstr:	mov	r0, #MODE_SVC
		msr	cpsr_c, r0			@ Enable interrupts
		mov	r0, lr
		mov	r1, sp
		adrsvc	al, lr, ret_from_sys_call
		b	SYMBOL_NAME(do_undefinstr)

		.align	5
__pabt_usr:	sub	sp, sp, #S_FRAME_SIZE		@ Allocate frame size in one go
		stmia	sp, {r0 - r12}			@ Save r0 - r12
		ldr	r4, .LCabt
		add	r8, sp, #S_PC
		ldmia	r4, {r5 - r7}			@ Get USR pc, cpsr
		stmia	r8, {r5 - r7}			@ Save USR pc, cpsr, old_r0
		stmdb	r8, {sp, lr}^			@ Save sp_usr lr_usr
		alignment_trap r4, r7, __temp_abt
		zero_fp
		mov	r0, #MODE_SVC
		msr	cpsr_c, r0			@ Enable interrupts
		mov	r0, r5				@ address (pc)
		mov	r1, sp				@ regs
		bl	SYMBOL_NAME(do_PrefetchAbort)	@ call abort handler
		teq	r0, #0				@ Does this still apply???
		bne	ret_from_sys_call		@ Return from exception
#ifdef DEBUG_UNDEF
		adr	r0, t
		bl	SYMBOL_NAME(printk)
#endif
		mov	r0, r5
		mov	r1, sp
		and	r2, r6, #31
		bl	SYMBOL_NAME(do_undefinstr)
		ldr	lr, [sp, #S_PSR]		@ Get USR cpsr
		msr	spsr, lr
		ldmia	sp, {r0 - pc}^			@ Restore USR registers

#ifdef DEBUG_UNDEF
t:		.ascii "Prefetch -> undefined instruction\n\0"
		.align
#endif

#include "entry-common.S"

		.text

#ifndef __ARM_ARCH_4__
.Larm700bug:	ldr	r0, [sp, #S_PSR]		@ Get calling cpsr
		str	lr, [r8]
		msr	spsr, r0
		ldmia	sp, {r0 - lr}^			@ Get calling r0 - lr
		mov	r0, r0
		ldr	lr, [sp, #S_PC]			@ Get PC
		add	sp, sp, #S_FRAME_SIZE
		movs	pc, lr
#endif

/*
 * Register switch for ARMv3 and ARMv4 processors
 * r0 = previous, r1 = next, return previous.
 * previous and next are guaranteed not to be the same.
 */
ENTRY(__switch_to)
		stmfd	sp!, {r4 - sl, fp, lr}		@ Store most regs on stack
		mrs	ip, cpsr
		str	ip, [sp, #-4]!			@ Save cpsr_SVC
		str	sp, [r0, #TSS_SAVE]		@ Save sp_SVC
		ldr	sp, [r1, #TSS_SAVE]		@ Get saved sp_SVC
		ldr	r2, [r1, #TSS_DOMAIN]
		ldr	ip, [sp], #4
		mcr	p15, 0, r2, c3, c0		@ Set domain register
		msr	spsr, ip			@ Save tasks CPSR into SPSR for this return
		ldmfd	sp!, {r4 - sl, fp, pc}^		@ Load all regs saved previously

		.section ".text.init",#alloc,#execinstr
/*
 * Vector stubs.  NOTE that we only align 'vector_IRQ' to a cache line boundary,
 * and we rely on each stub being exactly 48 (1.5 cache lines) in size.  This
 * means that we only ever load two cache lines for this code, or one if we're
 * lucky.  We also copy this code to 0x200 so that we can use branches in the
 * vectors, rather than ldr's.
 */
		.align	5
__stubs_start:
/*
 * Interrupt dispatcher
 * Enter in IRQ mode, spsr = SVC/USR CPSR, lr = SVC/USR PC
 */
vector_IRQ:	@
		@ save mode specific registers
		@
		ldr	r13, .LCsirq
		sub	lr, lr, #4
		str	lr, [r13]			@ save lr_IRQ
		mrs	lr, spsr
		str	lr, [r13, #4]			@ save spsr_IRQ
		@
		@ now branch to the relevent MODE handling routine
		@
		mov	r13, #I_BIT | MODE_SVC
		msr	spsr_c, r13			@ switch to SVC_32 mode

		and	lr, lr, #15
		ldr	lr, [pc, lr, lsl #2]
		movs	pc, lr				@ Changes mode and branches

.LCtab_irq:	.word	__irq_usr			@  0  (USR_26 / USR_32)
		.word	__irq_invalid			@  1  (FIQ_26 / FIQ_32)
		.word	__irq_invalid			@  2  (IRQ_26 / IRQ_32)
		.word	__irq_svc			@  3  (SVC_26 / SVC_32)
		.word	__irq_invalid			@  4
		.word	__irq_invalid			@  5
		.word	__irq_invalid			@  6
		.word	__irq_invalid			@  7
		.word	__irq_invalid			@  8
		.word	__irq_invalid			@  9
		.word	__irq_invalid			@  a
		.word	__irq_invalid			@  b
		.word	__irq_invalid			@  c
		.word	__irq_invalid			@  d
		.word	__irq_invalid			@  e
		.word	__irq_invalid			@  f

		.align	5

/*
 * Data abort dispatcher - dispatches it to the correct handler for the processor mode
 * Enter in ABT mode, spsr = USR CPSR, lr = USR PC
 */
vector_data:	@
		@ save mode specific registers
		@
		ldr	r13, .LCsabt
		sub	lr, lr, #8
		str	lr, [r13]
		mrs	lr, spsr
		str	lr, [r13, #4]
		@
		@ now branch to the relevent MODE handling routine
		@
		mov	r13, #I_BIT | MODE_SVC
		msr	spsr_c, r13			@ switch to SVC_32 mode

		and	lr, lr, #15
		ldr	lr, [pc, lr, lsl #2]
		movs	pc, lr				@ Changes mode and branches

.LCtab_dabt:	.word	__dabt_usr			@  0  (USR_26 / USR_32)
		.word	__dabt_invalid			@  1  (FIQ_26 / FIQ_32)
		.word	__dabt_invalid			@  2  (IRQ_26 / IRQ_32)
		.word	__dabt_svc			@  3  (SVC_26 / SVC_32)
		.word	__dabt_invalid			@  4
		.word	__dabt_invalid			@  5
		.word	__dabt_invalid			@  6
		.word	__dabt_invalid			@  7
		.word	__dabt_invalid			@  8
		.word	__dabt_invalid			@  9
		.word	__dabt_invalid			@  a
		.word	__dabt_invalid			@  b
		.word	__dabt_invalid			@  c
		.word	__dabt_invalid			@  d
		.word	__dabt_invalid			@  e
		.word	__dabt_invalid			@  f

		.align	5

/*
 * Prefetch abort dispatcher - dispatches it to the correct handler for the processor mode
 * Enter in ABT mode, spsr = USR CPSR, lr = USR PC
 */
vector_prefetch:
		@
		@ save mode specific registers
		@
		ldr	r13, .LCsabt
		sub	lr, lr, #4
		str	lr, [r13]			@ save lr_ABT
		mrs	lr, spsr
		str	lr, [r13, #4]			@ save spsr_ABT
		@
		@ now branch to the relevent MODE handling routine
		@
		mov	r13, #I_BIT | MODE_SVC
		msr	spsr_c, r13			@ switch to SVC_32 mode

		ands	lr, lr, #15
		ldr	lr, [pc, lr, lsl #2]
		movs	pc, lr

.LCtab_pabt:	.word	__pabt_usr			@  0 (USR_26 / USR_32)
		.word	__pabt_invalid			@  1 (FIQ_26 / FIQ_32)
		.word	__pabt_invalid			@  2 (IRQ_26 / IRQ_32)
		.word	__pabt_svc			@  3 (SVC_26 / SVC_32)
		.word	__pabt_invalid			@  4
		.word	__pabt_invalid			@  5
		.word	__pabt_invalid			@  6
		.word	__pabt_invalid			@  7
		.word	__pabt_invalid			@  8
		.word	__pabt_invalid			@  9
		.word	__pabt_invalid			@  a
		.word	__pabt_invalid			@  b
		.word	__pabt_invalid			@  c
		.word	__pabt_invalid			@  d
		.word	__pabt_invalid			@  e
		.word	__pabt_invalid			@  f

		.align	5

/*
 * Undef instr entry dispatcher - dispatches it to the correct handler for the processor mode
 * Enter in UND mode, spsr = SVC/USR CPSR, lr = SVC/USR PC
 */
vector_undefinstr:
		@
		@ save mode specific registers
		@
		ldr	r13, .LCsund
		str	lr, [r13]			@ save lr_UND
		mrs	lr, spsr
		str	lr, [r13, #4]			@ save spsr_UND
		@
		@ now branch to the relevent MODE handling routine
		@
		mov	r13, #I_BIT | MODE_SVC
		msr	spsr_c, r13			@ switch to SVC_32 mode

		and	lr, lr, #15
		ldr	lr, [pc, lr, lsl #2]
		movs	pc, lr				@ Changes mode and branches

.LCtab_und:	.word	__und_usr			@  0 (USR_26 / USR_32)
		.word	__und_invalid			@  1 (FIQ_26 / FIQ_32)
		.word	__und_invalid			@  2 (IRQ_26 / IRQ_32)
		.word	__und_svc			@  3 (SVC_26 / SVC_32)
		.word	__und_invalid			@  4
		.word	__und_invalid			@  5
		.word	__und_invalid			@  6
		.word	__und_invalid			@  7
		.word	__und_invalid			@  8
		.word	__und_invalid			@  9
		.word	__und_invalid			@  a
		.word	__und_invalid			@  b
		.word	__und_invalid			@  c
		.word	__und_invalid			@  d
		.word	__und_invalid			@  e
		.word	__und_invalid			@  f

		.align	5

/*=============================================================================
 * Undefined FIQs
 *-----------------------------------------------------------------------------
 * Enter in FIQ mode, spsr = ANY CPSR, lr = ANY PC
 * MUST PRESERVE SVC SPSR, but need to switch to SVC mode to show our msg.
 * Basically to switch modes, we *HAVE* to clobber one register...  brain
 * damage alert!  I don't think that we can execute any code in here in any
 * other mode than FIQ...  Ok you can switch to another mode, but you can't
 * get out of that mode without clobbering one register.
 */
vector_FIQ:	disable_fiq
		subs	pc, lr, #4

/*=============================================================================
 * Address exception handler
 *-----------------------------------------------------------------------------
 * These aren't too critical.
 * (they're not supposed to happen, and won't happen in 32-bit data mode).
 */

vector_addrexcptn:
		b	vector_addrexcptn

/*
 * We group all the following data together to optimise
 * for CPUs with separate I & D caches.
 */
		.align	5

.LCvswi:	.word	vector_swi

.LCsirq:	.word	__temp_irq
.LCsund:	.word	__temp_und
.LCsabt:	.word	__temp_abt

__stubs_end:

		.equ	__real_stubs_start, .LCvectors + 0x200

.LCvectors:	swi	SYS_ERROR0
		b	__real_stubs_start + (vector_undefinstr - __stubs_start)
		ldr	pc, __real_stubs_start + (.LCvswi - __stubs_start)
		b	__real_stubs_start + (vector_prefetch - __stubs_start)
		b	__real_stubs_start + (vector_data - __stubs_start)
		b	__real_stubs_start + (vector_addrexcptn - __stubs_start)
		b	__real_stubs_start + (vector_IRQ - __stubs_start)
		b	__real_stubs_start + (vector_FIQ - __stubs_start)

ENTRY(__trap_init)
		stmfd	sp!, {r4 - r6, lr}

		adr	r1, .LCvectors			@ set up the vectors
		mov	r0, #0
		ldmia	r1, {r1, r2, r3, r4, r5, r6, ip, lr}
		stmia	r0, {r1, r2, r3, r4, r5, r6, ip, lr}

		add	r2, r0, #0x200
		adr	r0, __stubs_start		@ copy stubs to 0x200
		adr	r1, __stubs_end
1:		ldr	r3, [r0], #4
		str	r3, [r2], #4
		cmp	r0, r1
		blt	1b
		LOADREGS(fd, sp!, {r4 - r6, pc})

		.data

/*
 * Do not reorder these, and do not insert extra data between...
 */

__temp_irq:	.word	0				@ saved lr_irq
		.word	0				@ saved spsr_irq
		.word	-1				@ old_r0
__temp_und:	.word	0				@ Saved lr_und
		.word	0				@ Saved spsr_und
		.word	-1				@ old_r0
__temp_abt:	.word	0				@ Saved lr_abt
		.word	0				@ Saved spsr_abt
		.word	-1				@ old_r0

		.globl	SYMBOL_NAME(cr_alignment)
		.globl	SYMBOL_NAME(cr_no_alignment)
SYMBOL_NAME(cr_alignment):
		.space	4
SYMBOL_NAME(cr_no_alignment):
		.space	4