head_64.s

linux 内核源代码

	b	.do_hash_page	 	/* Try to handle as hpte fault */

	.align	7
	.globl instruction_access_common
instruction_access_common:
	EXCEPTION_PROLOG_COMMON(0x400, PACA_EXGEN)
	ld	r3,_NIP(r1)
	andis.	r4,r12,0x5820
	li	r5,0x400
	b	.do_hash_page		/* Try to handle as hpte fault */

/*
 * Here is the common SLB miss user that is used when going to virtual
 * mode for SLB misses, that is currently not used
 */
#ifdef __DISABLED__
	.align	7
	.globl	slb_miss_user_common
slb_miss_user_common:
	mflr	r10
	std	r3,PACA_EXGEN+EX_DAR(r13)
	stw	r9,PACA_EXGEN+EX_CCR(r13)
	std	r10,PACA_EXGEN+EX_LR(r13)
	std	r11,PACA_EXGEN+EX_SRR0(r13)
	bl	.slb_allocate_user

	ld	r10,PACA_EXGEN+EX_LR(r13)
	ld	r3,PACA_EXGEN+EX_R3(r13)
	lwz	r9,PACA_EXGEN+EX_CCR(r13)
	ld	r11,PACA_EXGEN+EX_SRR0(r13)
	mtlr	r10
	beq-	slb_miss_fault

	andi.	r10,r12,MSR_RI		/* check for unrecoverable exception */
	beq-	unrecov_user_slb
	mfmsr	r10

.machine push
.machine "power4"
	mtcrf	0x80,r9
.machine pop

	clrrdi	r10,r10,2		/* clear RI before setting SRR0/1 */
	mtmsrd	r10,1

	mtspr	SRR0,r11
	mtspr	SRR1,r12

	ld	r9,PACA_EXGEN+EX_R9(r13)
	ld	r10,PACA_EXGEN+EX_R10(r13)
	ld	r11,PACA_EXGEN+EX_R11(r13)
	ld	r12,PACA_EXGEN+EX_R12(r13)
	ld	r13,PACA_EXGEN+EX_R13(r13)
	rfid
	b	.

slb_miss_fault:
	EXCEPTION_PROLOG_COMMON(0x380, PACA_EXGEN)
	ld	r4,PACA_EXGEN+EX_DAR(r13)
	li	r5,0
	std	r4,_DAR(r1)
	std	r5,_DSISR(r1)
	b	handle_page_fault

unrecov_user_slb:
	EXCEPTION_PROLOG_COMMON(0x4200, PACA_EXGEN)
	DISABLE_INTS
	bl	.save_nvgprs
1:	addi	r3,r1,STACK_FRAME_OVERHEAD
	bl	.unrecoverable_exception
	b	1b

#endif /* __DISABLED__ */


/*
 * r13 points to the PACA, r9 contains the saved CR,
 * r12 contain the saved SRR1, SRR0 is still ready for return
 * r3 has the faulting address
 * r9 - r13 are saved in paca->exslb.
 * r3 is saved in paca->slb_r3
 * We assume we aren't going to take any exceptions during this procedure.
 */
_GLOBAL(slb_miss_realmode)
	mflr	r10

	stw	r9,PACA_EXSLB+EX_CCR(r13)	/* save CR in exc. frame */
	std	r10,PACA_EXSLB+EX_LR(r13)	/* save LR */

	bl	.slb_allocate_realmode

	/* All done -- return from exception. */

	ld	r10,PACA_EXSLB+EX_LR(r13)
	ld	r3,PACA_EXSLB+EX_R3(r13)
	lwz	r9,PACA_EXSLB+EX_CCR(r13)	/* get saved CR */
#ifdef CONFIG_PPC_ISERIES
BEGIN_FW_FTR_SECTION
	ld	r11,PACALPPACAPTR(r13)
	ld	r11,LPPACASRR0(r11)		/* get SRR0 value */
END_FW_FTR_SECTION_IFSET(FW_FEATURE_ISERIES)
#endif /* CONFIG_PPC_ISERIES */

	mtlr	r10

	andi.	r10,r12,MSR_RI	/* check for unrecoverable exception */
	beq-	unrecov_slb

.machine	push
.machine	"power4"
	mtcrf	0x80,r9
	mtcrf	0x01,r9		/* slb_allocate uses cr0 and cr7 */
.machine	pop

#ifdef CONFIG_PPC_ISERIES
BEGIN_FW_FTR_SECTION
	mtspr	SPRN_SRR0,r11
	mtspr	SPRN_SRR1,r12
END_FW_FTR_SECTION_IFSET(FW_FEATURE_ISERIES)
#endif /* CONFIG_PPC_ISERIES */
	ld	r9,PACA_EXSLB+EX_R9(r13)
	ld	r10,PACA_EXSLB+EX_R10(r13)
	ld	r11,PACA_EXSLB+EX_R11(r13)
	ld	r12,PACA_EXSLB+EX_R12(r13)
	ld	r13,PACA_EXSLB+EX_R13(r13)
	rfid
	b	.	/* prevent speculative execution */

unrecov_slb:
	EXCEPTION_PROLOG_COMMON(0x4100, PACA_EXSLB)
	DISABLE_INTS
	bl	.save_nvgprs
1:	addi	r3,r1,STACK_FRAME_OVERHEAD
	bl	.unrecoverable_exception
	b	1b

	.align	7
	.globl hardware_interrupt_common
	.globl hardware_interrupt_entry
hardware_interrupt_common:
	EXCEPTION_PROLOG_COMMON(0x500, PACA_EXGEN)
	FINISH_NAP
hardware_interrupt_entry:
	DISABLE_INTS
BEGIN_FTR_SECTION
	bl	.ppc64_runlatch_on
END_FTR_SECTION_IFSET(CPU_FTR_CTRL)
	addi	r3,r1,STACK_FRAME_OVERHEAD
	bl	.do_IRQ
	b	.ret_from_except_lite

#ifdef CONFIG_PPC_970_NAP
power4_fixup_nap:
	andc	r9,r9,r10
	std	r9,TI_LOCAL_FLAGS(r11)
	ld	r10,_LINK(r1)		/* make idle task do the */
	std	r10,_NIP(r1)		/* equivalent of a blr */
	blr
#endif

	.align	7
	.globl alignment_common
alignment_common:
	mfspr	r10,SPRN_DAR
	std	r10,PACA_EXGEN+EX_DAR(r13)
	mfspr	r10,SPRN_DSISR
	stw	r10,PACA_EXGEN+EX_DSISR(r13)
	EXCEPTION_PROLOG_COMMON(0x600, PACA_EXGEN)
	ld	r3,PACA_EXGEN+EX_DAR(r13)
	lwz	r4,PACA_EXGEN+EX_DSISR(r13)
	std	r3,_DAR(r1)
	std	r4,_DSISR(r1)
	bl	.save_nvgprs
	addi	r3,r1,STACK_FRAME_OVERHEAD
	ENABLE_INTS
	bl	.alignment_exception
	b	.ret_from_except

	.align	7
	.globl program_check_common
program_check_common:
	EXCEPTION_PROLOG_COMMON(0x700, PACA_EXGEN)
	bl	.save_nvgprs
	addi	r3,r1,STACK_FRAME_OVERHEAD
	ENABLE_INTS
	bl	.program_check_exception
	b	.ret_from_except

	.align	7
	.globl fp_unavailable_common
fp_unavailable_common:
	EXCEPTION_PROLOG_COMMON(0x800, PACA_EXGEN)
	bne	1f			/* if from user, just load it up */
	bl	.save_nvgprs
	addi	r3,r1,STACK_FRAME_OVERHEAD
	ENABLE_INTS
	bl	.kernel_fp_unavailable_exception
	BUG_OPCODE
1:	b	.load_up_fpu

	.align	7
	.globl altivec_unavailable_common
altivec_unavailable_common:
	EXCEPTION_PROLOG_COMMON(0xf20, PACA_EXGEN)
#ifdef CONFIG_ALTIVEC
BEGIN_FTR_SECTION
	bne	.load_up_altivec	/* if from user, just load it up */
END_FTR_SECTION_IFSET(CPU_FTR_ALTIVEC)
#endif
	bl	.save_nvgprs
	addi	r3,r1,STACK_FRAME_OVERHEAD
	ENABLE_INTS
	bl	.altivec_unavailable_exception
	b	.ret_from_except

#ifdef CONFIG_ALTIVEC
/*
 * load_up_altivec(unused, unused, tsk)
 * Disable VMX for the task which had it previously,
 * and save its vector registers in its thread_struct.
 * Enables the VMX for use in the kernel on return.
 * On SMP we know the VMX is free, since we give it up every
 * switch (ie, no lazy save of the vector registers).
 * On entry: r13 == 'current' && last_task_used_altivec != 'current'
 */
_STATIC(load_up_altivec)
	mfmsr	r5			/* grab the current MSR */
	oris	r5,r5,MSR_VEC@h
	mtmsrd	r5			/* enable use of VMX now */
	isync

/*
 * For SMP, we don't do lazy VMX switching because it just gets too
 * horrendously complex, especially when a task switches from one CPU
 * to another.  Instead we call giveup_altvec in switch_to.
 * VRSAVE isn't dealt with here, that is done in the normal context
 * switch code. Note that we could rely on vrsave value to eventually
 * avoid saving all of the VREGs here...
 */
#ifndef CONFIG_SMP
	ld	r3,last_task_used_altivec@got(r2)
	ld	r4,0(r3)
	cmpdi	0,r4,0
	beq	1f
	/* Save VMX state to last_task_used_altivec's THREAD struct */
	addi	r4,r4,THREAD
	SAVE_32VRS(0,r5,r4)
	mfvscr	vr0
	li	r10,THREAD_VSCR
	stvx	vr0,r10,r4
	/* Disable VMX for last_task_used_altivec */
	ld	r5,PT_REGS(r4)
	ld	r4,_MSR-STACK_FRAME_OVERHEAD(r5)
	lis	r6,MSR_VEC@h
	andc	r4,r4,r6
	std	r4,_MSR-STACK_FRAME_OVERHEAD(r5)
1:
#endif /* CONFIG_SMP */
	/* Hack: if we get an altivec unavailable trap with VRSAVE
	 * set to all zeros, we assume this is a broken application
	 * that fails to set it properly, and thus we switch it to
	 * all 1's
	 */
	mfspr	r4,SPRN_VRSAVE
	cmpdi	0,r4,0
	bne+	1f
	li	r4,-1
	mtspr	SPRN_VRSAVE,r4
1:
	/* enable use of VMX after return */
	ld	r4,PACACURRENT(r13)
	addi	r5,r4,THREAD		/* Get THREAD */
	oris	r12,r12,MSR_VEC@h
	std	r12,_MSR(r1)
	li	r4,1
	li	r10,THREAD_VSCR
	stw	r4,THREAD_USED_VR(r5)
	lvx	vr0,r10,r5
	mtvscr	vr0
	REST_32VRS(0,r4,r5)
#ifndef CONFIG_SMP
	/* Update last_task_used_math to 'current' */
	subi	r4,r5,THREAD		/* Back to 'current' */
	std	r4,0(r3)
#endif /* CONFIG_SMP */
	/* restore registers and return */
	b	fast_exception_return
#endif /* CONFIG_ALTIVEC */

/*
 * Hash table stuff
 */
	.align	7
_GLOBAL(do_hash_page)
	std	r3,_DAR(r1)
	std	r4,_DSISR(r1)

	andis.	r0,r4,0xa450		/* weird error? */
	bne-	handle_page_fault	/* if not, try to insert a HPTE */
BEGIN_FTR_SECTION
	andis.	r0,r4,0x0020		/* Is it a segment table fault? */
	bne-	do_ste_alloc		/* If so handle it */
END_FTR_SECTION_IFCLR(CPU_FTR_SLB)

	/*
	 * We need to set the _PAGE_USER bit if MSR_PR is set or if we are
	 * accessing a userspace segment (even from the kernel). We assume
	 * kernel addresses always have the high bit set.
	 */
	rlwinm	r4,r4,32-25+9,31-9,31-9	/* DSISR_STORE -> _PAGE_RW */
	rotldi	r0,r3,15		/* Move high bit into MSR_PR posn */
	orc	r0,r12,r0		/* MSR_PR | ~high_bit */
	rlwimi	r4,r0,32-13,30,30	/* becomes _PAGE_USER access bit */
	ori	r4,r4,1			/* add _PAGE_PRESENT */
	rlwimi	r4,r5,22+2,31-2,31-2	/* Set _PAGE_EXEC if trap is 0x400 */

	/*
	 * On iSeries, we soft-disable interrupts here, then
	 * hard-enable interrupts so that the hash_page code can spin on
	 * the hash_table_lock without problems on a shared processor.
	 */
	DISABLE_INTS

	/*
	 * r3 contains the faulting address
	 * r4 contains the required access permissions
	 * r5 contains the trap number
	 *
	 * at return r3 = 0 for success
	 */
	bl	.hash_page		/* build HPTE if possible */
	cmpdi	r3,0			/* see if hash_page succeeded */

#ifdef DO_SOFT_DISABLE
BEGIN_FW_FTR_SECTION
	/*
	 * If we had interrupts soft-enabled at the point where the
	 * DSI/ISI occurred, and an interrupt came in during hash_page,
	 * handle it now.
	 * We jump to ret_from_except_lite rather than fast_exception_return
	 * because ret_from_except_lite will check for and handle pending
	 * interrupts if necessary.
	 */
	beq	13f
END_FW_FTR_SECTION_IFSET(FW_FEATURE_ISERIES)
#endif
BEGIN_FW_FTR_SECTION
	/*
	 * Here we have interrupts hard-disabled, so it is sufficient
	 * to restore paca->{soft,hard}_enable and get out.
	 */
	beq	fast_exc_return_irq	/* Return from exception on success */
END_FW_FTR_SECTION_IFCLR(FW_FEATURE_ISERIES)

	/* For a hash failure, we don't bother re-enabling interrupts */
	ble-	12f

	/*
	 * hash_page couldn't handle it, set soft interrupt enable back
	 * to what it was before the trap.  Note that .local_irq_restore
	 * handles any interrupts pending at this point.
	 */
	ld	r3,SOFTE(r1)
	bl	.local_irq_restore
	b	11f

/* Here we have a page fault that hash_page can't handle. */
handle_page_fault:
	ENABLE_INTS
11:	ld	r4,_DAR(r1)
	ld	r5,_DSISR(r1)
	addi	r3,r1,STACK_FRAME_OVERHEAD
	bl	.do_page_fault
	cmpdi	r3,0
	beq+	13f
	bl	.save_nvgprs
	mr	r5,r3
	addi	r3,r1,STACK_FRAME_OVERHEAD
	lwz	r4,_DAR(r1)
	bl	.bad_page_fault
	b	.ret_from_except

13:	b	.ret_from_except_lite

/* We have a page fault that hash_page could handle but HV refused
 * the PTE insertion
 */
12:	bl	.save_nvgprs
	addi	r3,r1,STACK_FRAME_OVERHEAD
	ld	r4,_DAR(r1)
	bl	.low_hash_fault
	b	.ret_from_except

	/* here we have a segment miss */
do_ste_alloc:
	bl	.ste_allocate		/* try to insert stab entry */
	cmpdi	r3,0
	bne-	handle_page_fault
	b	fast_exception_return

/*
 * r13 points to the PACA, r9 contains the saved CR,
 * r11 and r12 contain the saved SRR0 and SRR1.
 * r9 - r13 are saved in paca->exslb.
 * We assume we aren't going to take any exceptions during this procedure.
 * We assume (DAR >> 60) == 0xc.
 */
	.align	7
_GLOBAL(do_stab_bolted)
	stw	r9,PACA_EXSLB+EX_CCR(r13)	/* save CR in exc. frame */
	std	r11,PACA_EXSLB+EX_SRR0(r13)	/* save SRR0 in exc. frame */

	/* Hash to the primary group */
	ld	r10,PACASTABVIRT(r13)
	mfspr	r11,SPRN_DAR
	srdi	r11,r11,28
	rldimi	r10,r11,7,52	/* r10 = first ste of the group */

	/* Calculate VSID */
	/* This is a kernel address, so protovsid = ESID */
	ASM_VSID_SCRAMBLE(r11, r9, 256M)
	rldic	r9,r11,12,16	/* r9 = vsid << 12 */

	/* Search the primary group for a free entry */
1:	ld	r11,0(r10)	/* Test valid bit of the current ste	*/
	andi.	r11,r11,0x80
	beq	2f
	addi	r10,r10,16
	andi.	r11,r10,0x70
	bne	1b

	/* Stick for only searching the primary group for now.		*/
	/* At least for now, we use a very simple random castout scheme */
	/* Use the TB as a random number ;  OR in 1 to avoid entry 0	*/
	mftb	r11
	rldic	r11,r11,4,57	/* r11 = (r11 << 4) & 0x70 */
	ori	r11,r11,0x10

	/* r10 currently points to an ste one past the group of interest */
	/* make it point to the randomly selected entry			*/
	subi	r10,r10,128
	or 	r10,r10,r11	/* r10 is the entry to invalidate	*/

	isync			/* mark the entry invalid		*/
	ld	r11,0(r10)
	rldicl	r11,r11,56,1	/* clear the valid bit */
	rotldi	r11,r11,8
	std	r11,0(r10)
	sync

	clrrdi	r11,r11,28	/* Get the esid part of the ste		*/
	slbie	r11

2:	std	r9,8(r10)	/* Store the vsid part of the ste	*/
	eieio

	mfspr	r11,SPRN_DAR		/* Get the new esid			*/
	clrrdi	r11,r11,28	/* Permits a full 32b of ESID		*/
	ori	r11,r11,0x90	/* Turn on valid and kp			*/
	std	r11,0(r10)	/* Put new entry back into the stab	*/

	sync

	/* All done -- return from exception. */
	lwz	r9,PACA_EXSLB+EX_CCR(r13)	/* get saved CR */
	ld	r11,PACA_EXSLB+EX_SRR0(r13)	/* get saved SRR0 */

	andi.	r10,r12,MSR_RI
	beq-	unrecov_slb

	mtcrf	0x80,r9			/* restore CR */

	mfmsr	r10
	clrrdi	r10,r10,2
	mtmsrd	r10,1

	mtspr	SPRN_SRR0,r11
	mtspr	SPRN_SRR1,r12
	ld	r9,PACA_EXSLB+EX_R9(r13)
	ld	r10,PACA_EXSLB+EX_R10(r13)
	ld	r11,PACA_EXSLB+EX_R11(r13)
	ld	r12,PACA_EXSLB+EX_R12(r13)
	ld	r13,PACA_EXSLB+EX_R13(r13)
	rfid
	b	.	/* prevent speculative execution */

/*
 * Space for CPU0's segment table.
 *
 * On iSeries, the hypervisor must fill in at least one entry before
 * we get control (with relocate on).  The address is given to the hv
 * as a page number (see xLparMap below), so this must be at a
 * fixed address (the linker can't compute (u64)&initial_stab >>
 * PAGE_SHIFT).
 */
	. = STAB0_OFFSET	/* 0x6000 */
	.globl initial_stab
initial_stab:
	.space	4096

#ifdef CONFIG_PPC_PSERIES
/*
 * Data area reserved for FWNMI option.
 * This address (0x7000) is fixed by the RPA.
 */
	.= 0x7000
	.globl fwnmi_data_area
fwnmi_data_area:
#endif /* CONFIG_PPC_PSERIES */

	/* iSeries does not use the FWNMI stuff, so it is safe to put
	 * this here, even if we later allow kernels that will boot on
	 * both pSeries and iSeries */
#ifdef CONFIG_PPC_ISERIES
        . = LPARMAP_PHYS
	.globl xLparMap
xLparMap: