head.s

优龙2410linux2.6.8内核源代码

	andn	%g1, %l3, %g1

	/* NOTE: We hold on to %g1 paddr base as we need it below to lock
	 * NOTE: the PROM cif code into the TLB.
	 */

	or	%g5, %g1, %g5		/* Or it into TAG being built.        */

	clr	%l0			/* TLB entry walker. */
	sethi	%hi(KERNBASE), %g3	/* 4M lower limit */
	sethi	%hi(KERNBASE<<1), %g7	/* 8M upper limit */
	mov	TLB_TAG_ACCESS, %l7
1:
	/* Yes, the nops seem to be necessary for now, don't ask me why. -DaveM */
	ldxa	[%l0] ASI_ITLB_TAG_READ, %g1
	nop
	nop
	nop
	andn	%g1, %l2, %g1		/* Get vaddr */
	cmp	%g1, %g3
	blu,pn	%xcc, 2f
	 cmp	%g1, %g7
	bgeu,pn	%xcc, 2f
	 nop
	stxa	%g0, [%l7] ASI_IMMU
	stxa	%g0, [%l0] ASI_ITLB_DATA_ACCESS
	membar	#Sync
2:
	cmp	%l0, (63 << 3)
	blu,pt	%xcc, 1b
	 add	%l0, (1 << 3), %l0

	nop; nop; nop

	clr	%l0			/* TLB entry walker. */
1:
	/* Yes, the nops seem to be necessary for now, don't ask me why. -DaveM */
	ldxa	[%l0] ASI_DTLB_TAG_READ, %g1
	nop
	nop
	nop
	andn	%g1, %l2, %g1		/* Get vaddr */
	cmp	%g1, %g3
	blu,pn	%xcc, 2f
	 cmp	%g1, %g7
	bgeu,pn	%xcc, 2f
	 nop
	stxa	%g0, [%l7] ASI_DMMU
	stxa	%g0, [%l0] ASI_DTLB_DATA_ACCESS
	membar	#Sync
2:
	cmp	%l0, (63 << 3)
	blu,pt	%xcc, 1b
	 add	%l0, (1 << 3), %l0

	nop; nop; nop


	/* PROM never puts any TLB entries into the MMU with the lock bit
	 * set.  So we gladly use tlb entry 63 for KERNBASE. And maybe 62 too.
	 */

	sethi	%hi(KERNBASE), %g3
	mov	(63 << 3), %g7
	stxa	%g3, [%l7] ASI_DMMU		/* KERNBASE into TLB TAG	*/
	stxa	%g5, [%g7] ASI_DTLB_DATA_ACCESS	/* TTE into TLB DATA		*/
	membar	#Sync
	stxa	%g3, [%l7] ASI_IMMU		/* KERNBASE into TLB TAG	*/
	stxa	%g5, [%g7] ASI_ITLB_DATA_ACCESS	/* TTE into TLB DATA		*/
	membar	#Sync
	flush	%g3
	membar	#Sync
	sethi	%hi(_end), %g3			/* Check for bigkernel case */
	or	%g3, %lo(_end), %g3
	srl	%g3, 23, %g3			/* Check if _end > 8M */
	brz,pt	%g3, 2f
	 sethi	%hi(KERNBASE), %g3		/* Restore for fixup code below */
	sethi	%hi(0x400000), %g3
	or	%g3, %lo(0x400000), %g3
	add	%g5, %g3, %g5			/* New tte data */
	andn	%g5, (_PAGE_G), %g5
	sethi	%hi(KERNBASE+0x400000), %g3
	or	%g3, %lo(KERNBASE+0x400000), %g3
	mov	(62 << 3), %g7
	stxa	%g3, [%l7] ASI_DMMU
	stxa	%g5, [%g7] ASI_DTLB_DATA_ACCESS
	membar	#Sync
	stxa	%g3, [%l7] ASI_IMMU
	stxa	%g5, [%g7] ASI_ITLB_DATA_ACCESS
	membar	#Sync
	flush	%g3
	membar	#Sync
	sethi	%hi(KERNBASE), %g3		/* Restore for fixup code below */
2:	ba,pt	%xcc, 1f
	 nop
1:
	set	sun4u_init, %g2
	jmpl    %g2 + %g0, %g0
	 nop

sun4u_init:
	/* Set ctx 0 */
	mov	PRIMARY_CONTEXT, %g7
	stxa	%g0, [%g7] ASI_DMMU
	membar	#Sync

	mov	SECONDARY_CONTEXT, %g7
	stxa	%g0, [%g7] ASI_DMMU
	membar	#Sync

	/* We are now safely (we hope) in Nucleus context (0), rewrite
	 * the KERNBASE TTE's so they no longer have the global bit set.
	 * Don't forget to setup TAG_ACCESS first 8-)
	 */
	mov	TLB_TAG_ACCESS, %g2
	stxa	%g3, [%g2] ASI_IMMU
	stxa	%g3, [%g2] ASI_DMMU
	membar	#Sync

	BRANCH_IF_ANY_CHEETAH(g1,g5,cheetah_tlb_fixup)

	ba,pt	%xcc, spitfire_tlb_fixup
	 nop

cheetah_tlb_fixup:
	set	(0 << 16) | (15 << 3), %g7
	ldxa	[%g7] ASI_ITLB_DATA_ACCESS, %g0
	ldxa	[%g7] ASI_ITLB_DATA_ACCESS, %g1
	andn	%g1, (_PAGE_G), %g1
	stxa	%g1, [%g7] ASI_ITLB_DATA_ACCESS
	membar	#Sync

	ldxa	[%g7] ASI_DTLB_DATA_ACCESS, %g0
	ldxa	[%g7] ASI_DTLB_DATA_ACCESS, %g1
	andn	%g1, (_PAGE_G), %g1
	stxa	%g1, [%g7] ASI_DTLB_DATA_ACCESS
	membar	#Sync

	/* Kill instruction prefetch queues. */
	flush	%g3
	membar	#Sync

	mov	2, %g2		/* Set TLB type to cheetah+. */
	BRANCH_IF_CHEETAH_PLUS_OR_FOLLOWON(g5,g7,1f)

	mov	1, %g2		/* Set TLB type to cheetah. */

1:	sethi	%hi(tlb_type), %g5
	stw	%g2, [%g5 + %lo(tlb_type)]

	/* Patch copy/page operations to cheetah optimized versions. */
	call	cheetah_patch_copyops
	 nop
	call	cheetah_patch_cachetlbops
	 nop

	ba,pt	%xcc, tlb_fixup_done
	 nop

spitfire_tlb_fixup:
	mov	(63 << 3), %g7
	ldxa	[%g7] ASI_ITLB_DATA_ACCESS, %g1
	andn	%g1, (_PAGE_G), %g1
	stxa	%g1, [%g7] ASI_ITLB_DATA_ACCESS
	membar	#Sync

	ldxa	[%g7] ASI_DTLB_DATA_ACCESS, %g1
	andn	%g1, (_PAGE_G), %g1
	stxa	%g1, [%g7] ASI_DTLB_DATA_ACCESS
	membar	#Sync

	/* Kill instruction prefetch queues. */
	flush	%g3
	membar	#Sync

	/* Set TLB type to spitfire. */
	mov	0, %g2
	sethi	%hi(tlb_type), %g5
	stw	%g2, [%g5 + %lo(tlb_type)]

tlb_fixup_done:
	sethi	%hi(init_thread_union), %g6
	or	%g6, %lo(init_thread_union), %g6
	ldx	[%g6 + TI_TASK], %g4
	mov	%sp, %l6
	mov	%o4, %l7

#if 0	/* We don't do it like this anymore, but for historical hack value
	 * I leave this snippet here to show how crazy we can be sometimes. 8-)
	 */

	/* Setup "Linux Current Register", thanks Sun 8-) */
	wr	%g0, 0x1, %pcr

	/* Blackbird errata workaround.  See commentary in
	 * smp.c:smp_percpu_timer_interrupt() for more
	 * information.
	 */
	ba,pt	%xcc, 99f
	 nop
	.align	64
99:	wr	%g6, %g0, %pic
	rd	%pic, %g0
#endif

	wr	%g0, ASI_P, %asi
	mov	1, %g5
	sllx	%g5, THREAD_SHIFT, %g5
	sub	%g5, (STACKFRAME_SZ + STACK_BIAS), %g5
	add	%g6, %g5, %sp
	mov	0, %fp

	wrpr	%g0, 0, %wstate
	wrpr	%g0, 0x0, %tl

	/* Clear the bss */
	sethi	%hi(__bss_start), %o0
	or	%o0, %lo(__bss_start), %o0
	sethi	%hi(_end), %o1
	or	%o1, %lo(_end), %o1
	call	__bzero
	 sub	%o1, %o0, %o1

	mov	%l6, %o1			! OpenPROM stack
	call	prom_init
	 mov	%l7, %o0			! OpenPROM cif handler

	/* Off we go.... */
	call	start_kernel
	 nop
	/* Not reached... */

/* IMPORTANT NOTE: Whenever making changes here, check
 * trampoline.S as well. -jj */
	.globl	setup_tba
setup_tba:	/* i0 = is_starfire */
	save	%sp, -160, %sp

	rdpr	%tba, %g7
	sethi	%hi(prom_tba), %o1
	or	%o1, %lo(prom_tba), %o1
	stx	%g7, [%o1]

	/* Setup "Linux" globals 8-) */
	rdpr	%pstate, %o1
	mov	%g6, %o2
	wrpr	%o1, (PSTATE_AG|PSTATE_IE), %pstate
	sethi	%hi(sparc64_ttable_tl0), %g5
	wrpr	%g5, %tba
	mov	%o2, %g6

	/* Set up MMU globals */
	wrpr	%o1, (PSTATE_MG|PSTATE_IE), %pstate

	/* Set fixed globals used by dTLB miss handler. */
#define KERN_HIGHBITS		((_PAGE_VALID|_PAGE_SZ4MB)^0xfffff80000000000)
#define KERN_LOWBITS		(_PAGE_CP | _PAGE_CV | _PAGE_P | _PAGE_W)

	mov	TSB_REG, %g1
	stxa	%g0, [%g1] ASI_DMMU
	membar	#Sync
	mov	TLB_SFSR, %g1
	sethi	%uhi(KERN_HIGHBITS), %g2
	or	%g2, %ulo(KERN_HIGHBITS), %g2
	sllx	%g2, 32, %g2
	or	%g2, KERN_LOWBITS, %g2

	BRANCH_IF_ANY_CHEETAH(g3,g7,cheetah_vpte_base)
	ba,pt	%xcc, spitfire_vpte_base
	 nop

cheetah_vpte_base:
	sethi		%uhi(VPTE_BASE_CHEETAH), %g3
	or		%g3, %ulo(VPTE_BASE_CHEETAH), %g3
	ba,pt		%xcc, 2f
	 sllx		%g3, 32, %g3

spitfire_vpte_base:
	sethi		%uhi(VPTE_BASE_SPITFIRE), %g3
	or		%g3, %ulo(VPTE_BASE_SPITFIRE), %g3
	sllx		%g3, 32, %g3

2:
	clr	%g7
#undef KERN_HIGHBITS
#undef KERN_LOWBITS

	/* Kill PROM timer */
	sethi	%hi(0x80000000), %o2
	sllx	%o2, 32, %o2
	wr	%o2, 0, %tick_cmpr

	BRANCH_IF_ANY_CHEETAH(o2,o3,1f)

	ba,pt	%xcc, 2f
	 nop

	/* Disable STICK_INT interrupts. */
1:
	sethi	%hi(0x80000000), %o2
	sllx	%o2, 32, %o2
	wr	%o2, %asr25

	/* Ok, we're done setting up all the state our trap mechanims needs,
	 * now get back into normal globals and let the PROM know what is up.
	 */
2:
	wrpr	%g0, %g0, %wstate
	wrpr	%o1, PSTATE_IE, %pstate

	call	init_irqwork_curcpu
	 nop

	sethi	%hi(sparc64_ttable_tl0), %g5
	call	prom_set_trap_table
	 mov	%g5, %o0

	rdpr	%pstate, %o1
	or	%o1, PSTATE_IE, %o1
	wrpr	%o1, 0, %pstate

	ret
	 restore

/*
 * The following skips make sure the trap table in ttable.S is aligned
 * on a 32K boundary as required by the v9 specs for TBA register.
 */
sparc64_boot_end:
	.skip	0x2000 + _start - sparc64_boot_end
bootup_user_stack_end:
	.skip	0x2000

#ifdef CONFIG_SBUS
/* This is just a hack to fool make depend config.h discovering
   strategy: As the .S files below need config.h, but
   make depend does not find it for them, we include config.h
   in head.S */
#endif

! 0x0000000000408000

#include "ttable.S"
#include "systbls.S"

	.align	1024
	.globl	swapper_pg_dir
swapper_pg_dir:
	.word	0

#include "etrap.S"
#include "rtrap.S"
#include "winfixup.S"
#include "entry.S"

	/* This is just anal retentiveness on my part... */
	.align	16384

	.data
	.align	8
	.globl	prom_tba, tlb_type
prom_tba:	.xword	0
tlb_type:	.word	0	/* Must NOT end up in BSS */
	.section	".fixup",#alloc,#execinstr
	.globl	__ret_efault
__ret_efault:
	ret
	 restore %g0, -EFAULT, %o0