entry.s

来自「linux-2.6.15.6」· S 代码 · 共 2,410 行 · 第 1/4 页

	 * virtual address.
	 *
	 * To use the alias page, you set %r26 up with the to TLB
	 * entry (identifying the physical page) and %r23 up with
	 * the from tlb entry (or nothing if only a to entry---for
	 * clear_user_page_asm) */
	.macro		do_alias	spc,tmp,tmp1,va,pte,prot,fault
	cmpib,COND(<>),n 0,\spc,\fault
	ldil		L%(TMPALIAS_MAP_START),\tmp
#if defined(CONFIG_64BIT) && (TMPALIAS_MAP_START >= 0x80000000)
	/* on LP64, ldi will sign extend into the upper 32 bits,
	 * which is behaviour we don't want */
	depdi		0,31,32,\tmp
#endif
	copy		\va,\tmp1
	DEPI		0,31,23,\tmp1
	cmpb,COND(<>),n	\tmp,\tmp1,\fault
	ldi		(_PAGE_DIRTY|_PAGE_WRITE|_PAGE_READ),\prot
	depd,z		\prot,8,7,\prot
	/*
	 * OK, it is in the temp alias region, check whether "from" or "to".
	 * Check "subtle" note in pacache.S re: r23/r26.
	 */
#ifdef CONFIG_64BIT
	extrd,u,*=	\va,41,1,%r0
#else
	extrw,u,=	\va,9,1,%r0
#endif
	or,COND(tr)	%r23,%r0,\pte
	or		%r26,%r0,\pte
	.endm 


	/*
	 * Align fault_vector_20 on 4K boundary so that both
	 * fault_vector_11 and fault_vector_20 are on the
	 * same page. This is only necessary as long as we
	 * write protect the kernel text, which we may stop
	 * doing once we use large page translations to cover
	 * the static part of the kernel address space.
	 */

	.export fault_vector_20

	.text

	.align 4096

fault_vector_20:
	/* First vector is invalid (0) */
	.ascii	"cows can fly"
	.byte 0
	.align 32

	hpmc		 1
	def		 2
	def		 3
	extint		 4
	def		 5
	itlb_20		 6
	def		 7
	def		 8
	def              9
	def		10
	def		11
	def		12
	def		13
	def		14
	dtlb_20		15
#if 0
	naitlb_20	16
#else
	def             16
#endif
	nadtlb_20	17
	def		18
	def		19
	dbit_20		20
	def		21
	def		22
	def		23
	def		24
	def		25
	def		26
	def		27
	def		28
	def		29
	def		30
	def		31

#ifndef CONFIG_64BIT

	.export fault_vector_11
	
	.align 2048

fault_vector_11:
	/* First vector is invalid (0) */
	.ascii	"cows can fly"
	.byte 0
	.align 32

	hpmc		 1
	def		 2
	def		 3
	extint		 4
	def		 5
	itlb_11		 6
	def		 7
	def		 8
	def              9
	def		10
	def		11
	def		12
	def		13
	def		14
	dtlb_11		15
#if 0
	naitlb_11	16
#else
	def             16
#endif
	nadtlb_11	17
	def		18
	def		19
	dbit_11		20
	def		21
	def		22
	def		23
	def		24
	def		25
	def		26
	def		27
	def		28
	def		29
	def		30
	def		31

#endif

	.import		handle_interruption,code
	.import		do_cpu_irq_mask,code

	/*
	 * r26 = function to be called
	 * r25 = argument to pass in
	 * r24 = flags for do_fork()
	 *
	 * Kernel threads don't ever return, so they don't need
	 * a true register context. We just save away the arguments
	 * for copy_thread/ret_ to properly set up the child.
	 */

#define CLONE_VM 0x100	/* Must agree with <linux/sched.h> */
#define CLONE_UNTRACED 0x00800000

	.export __kernel_thread, code
	.import do_fork
__kernel_thread:
	STREG	%r2, -RP_OFFSET(%r30)

	copy	%r30, %r1
	ldo	PT_SZ_ALGN(%r30),%r30
#ifdef CONFIG_64BIT
	/* Yo, function pointers in wide mode are little structs... -PB */
	ldd	24(%r26), %r2
	STREG	%r2, PT_GR27(%r1)	/* Store childs %dp */
	ldd	16(%r26), %r26

	STREG	%r22, PT_GR22(%r1)	/* save r22 (arg5) */
	copy	%r0, %r22		/* user_tid */
#endif
	STREG	%r26, PT_GR26(%r1)  /* Store function & argument for child */
	STREG	%r25, PT_GR25(%r1)
	ldil	L%CLONE_UNTRACED, %r26
	ldo	CLONE_VM(%r26), %r26   /* Force CLONE_VM since only init_mm */
	or	%r26, %r24, %r26      /* will have kernel mappings.	 */
	ldi	1, %r25			/* stack_start, signals kernel thread */
	stw	%r0, -52(%r30)	     	/* user_tid */
#ifdef CONFIG_64BIT
	ldo	-16(%r30),%r29		/* Reference param save area */
#endif
	BL	do_fork, %r2
	copy	%r1, %r24		/* pt_regs */

	/* Parent Returns here */

	LDREG	-PT_SZ_ALGN-RP_OFFSET(%r30), %r2
	ldo	-PT_SZ_ALGN(%r30), %r30
	bv	%r0(%r2)
	nop

	/*
	 * Child Returns here
	 *
	 * copy_thread moved args from temp save area set up above
	 * into task save area.
	 */

	.export	ret_from_kernel_thread
ret_from_kernel_thread:

	/* Call schedule_tail first though */
	BL	schedule_tail, %r2
	nop

	LDREG	TI_TASK-THREAD_SZ_ALGN(%r30), %r1
	LDREG	TASK_PT_GR25(%r1), %r26
#ifdef CONFIG_64BIT
	LDREG	TASK_PT_GR27(%r1), %r27
	LDREG	TASK_PT_GR22(%r1), %r22
#endif
	LDREG	TASK_PT_GR26(%r1), %r1
	ble	0(%sr7, %r1)
	copy	%r31, %r2

#ifdef CONFIG_64BIT
	ldo	-16(%r30),%r29		/* Reference param save area */
	loadgp				/* Thread could have been in a module */
#endif
#ifndef CONFIG_64BIT
	b	sys_exit
#else
	load32	sys_exit, %r1
	bv	%r0(%r1)
#endif
	ldi	0, %r26

	.import	sys_execve, code
	.export	__execve, code
__execve:
	copy	%r2, %r15
	copy	%r30, %r16
	ldo	PT_SZ_ALGN(%r30), %r30
	STREG	%r26, PT_GR26(%r16)
	STREG	%r25, PT_GR25(%r16)
	STREG	%r24, PT_GR24(%r16)
#ifdef CONFIG_64BIT
	ldo	-16(%r30),%r29		/* Reference param save area */
#endif
	BL	sys_execve, %r2
	copy	%r16, %r26

	cmpib,=,n 0,%r28,intr_return    /* forward */

	/* yes, this will trap and die. */
	copy	%r15, %r2
	copy	%r16, %r30
	bv	%r0(%r2)
	nop

	.align 4

	/*
	 * struct task_struct *_switch_to(struct task_struct *prev,
	 *	struct task_struct *next)
	 *
	 * switch kernel stacks and return prev */
	.export	_switch_to, code
_switch_to:
	STREG	 %r2, -RP_OFFSET(%r30)

	callee_save_float
	callee_save

	load32	_switch_to_ret, %r2

	STREG	%r2, TASK_PT_KPC(%r26)
	LDREG	TASK_PT_KPC(%r25), %r2

	STREG	%r30, TASK_PT_KSP(%r26)
	LDREG	TASK_PT_KSP(%r25), %r30
	LDREG	TASK_THREAD_INFO(%r25), %r25
	bv	%r0(%r2)
	mtctl   %r25,%cr30

_switch_to_ret:
	mtctl	%r0, %cr0		/* Needed for single stepping */
	callee_rest
	callee_rest_float

	LDREG	-RP_OFFSET(%r30), %r2
	bv	%r0(%r2)
	copy	%r26, %r28

	/*
	 * Common rfi return path for interruptions, kernel execve, and
	 * sys_rt_sigreturn (sometimes).  The sys_rt_sigreturn syscall will
	 * return via this path if the signal was received when the process
	 * was running; if the process was blocked on a syscall then the
	 * normal syscall_exit path is used.  All syscalls for traced
	 * proceses exit via intr_restore.
	 *
	 * XXX If any syscalls that change a processes space id ever exit
	 * this way, then we will need to copy %sr3 in to PT_SR[3..7], and
	 * adjust IASQ[0..1].
	 *
	 */

	.align 4096

	.export	syscall_exit_rfi
syscall_exit_rfi:
	mfctl   %cr30,%r16
	LDREG	TI_TASK(%r16), %r16	/* thread_info -> task_struct */
	ldo	TASK_REGS(%r16),%r16
	/* Force iaoq to userspace, as the user has had access to our current
	 * context via sigcontext. Also Filter the PSW for the same reason.
	 */
	LDREG	PT_IAOQ0(%r16),%r19
	depi	3,31,2,%r19
	STREG	%r19,PT_IAOQ0(%r16)
	LDREG	PT_IAOQ1(%r16),%r19
	depi	3,31,2,%r19
	STREG	%r19,PT_IAOQ1(%r16)
	LDREG   PT_PSW(%r16),%r19
	load32	USER_PSW_MASK,%r1
#ifdef CONFIG_64BIT
	load32	USER_PSW_HI_MASK,%r20
	depd    %r20,31,32,%r1
#endif
	and     %r19,%r1,%r19 /* Mask out bits that user shouldn't play with */
	load32	USER_PSW,%r1
	or      %r19,%r1,%r19 /* Make sure default USER_PSW bits are set */
	STREG   %r19,PT_PSW(%r16)

	/*
	 * If we aren't being traced, we never saved space registers
	 * (we don't store them in the sigcontext), so set them
	 * to "proper" values now (otherwise we'll wind up restoring
	 * whatever was last stored in the task structure, which might
	 * be inconsistent if an interrupt occured while on the gateway
	 * page) Note that we may be "trashing" values the user put in
	 * them, but we don't support the the user changing them.
	 */

	STREG   %r0,PT_SR2(%r16)
	mfsp    %sr3,%r19
	STREG   %r19,PT_SR0(%r16)
	STREG   %r19,PT_SR1(%r16)
	STREG   %r19,PT_SR3(%r16)
	STREG   %r19,PT_SR4(%r16)
	STREG   %r19,PT_SR5(%r16)
	STREG   %r19,PT_SR6(%r16)
	STREG   %r19,PT_SR7(%r16)

intr_return:
	/* NOTE: Need to enable interrupts incase we schedule. */
	ssm     PSW_SM_I, %r0

	/* Check for software interrupts */

	.import irq_stat,data

	load32	irq_stat,%r19
#ifdef CONFIG_SMP
	mfctl   %cr30,%r1
	ldw	TI_CPU(%r1),%r1 /* get cpu # - int */
	/* shift left ____cacheline_aligned (aka L1_CACHE_BYTES) amount
	** irq_stat[] is defined using ____cacheline_aligned.
	*/
#ifdef CONFIG_64BIT
	shld	%r1, 6, %r20
#else
	shlw	%r1, 5, %r20
#endif
	add     %r19,%r20,%r19	/* now have &irq_stat[smp_processor_id()] */
#endif /* CONFIG_SMP */

intr_check_resched:

	/* check for reschedule */
	mfctl   %cr30,%r1
	LDREG   TI_FLAGS(%r1),%r19	/* sched.h: TIF_NEED_RESCHED */
	bb,<,n	%r19,31-TIF_NEED_RESCHED,intr_do_resched /* forward */

intr_check_sig:
	/* As above */
	mfctl   %cr30,%r1
	LDREG	TI_FLAGS(%r1),%r19	/* sched.h: TIF_SIGPENDING */
	bb,<,n %r19, 31-TIF_SIGPENDING, intr_do_signal /* forward */

intr_restore:
	copy            %r16,%r29
	ldo             PT_FR31(%r29),%r1
	rest_fp         %r1
	rest_general    %r29

	/* inverse of virt_map */
	pcxt_ssm_bug
	rsm             PSW_SM_QUIET,%r0	/* prepare for rfi */
	tophys_r1       %r29

	/* Restore space id's and special cr's from PT_REGS
	 * structure pointed to by r29
	 */
	rest_specials	%r29

	/* IMPORTANT: rest_stack restores r29 last (we are using it)!
	 * It also restores r1 and r30.
	 */
	rest_stack

	rfi
	nop
	nop
	nop
	nop
	nop
	nop
	nop
	nop

	.import schedule,code
intr_do_resched:
	/* Only do reschedule if we are returning to user space */
	LDREG	PT_IASQ0(%r16), %r20
	CMPIB= 0,%r20,intr_restore /* backward */
	nop
	LDREG	PT_IASQ1(%r16), %r20
	CMPIB= 0,%r20,intr_restore /* backward */
	nop

#ifdef CONFIG_64BIT
	ldo	-16(%r30),%r29		/* Reference param save area */
#endif

	ldil	L%intr_check_sig, %r2
#ifndef CONFIG_64BIT
	b	schedule
#else
	load32	schedule, %r20
	bv	%r0(%r20)
#endif
	ldo	R%intr_check_sig(%r2), %r2


	.import do_signal,code
intr_do_signal:
	/* 
		This check is critical to having LWS
		working. The IASQ is zero on the gateway
		page and we cannot deliver any signals until
		we get off the gateway page.

		Only do signals if we are returning to user space 
	*/
	LDREG	PT_IASQ0(%r16), %r20
	CMPIB= 0,%r20,intr_restore /* backward */
	nop
	LDREG	PT_IASQ1(%r16), %r20
	CMPIB= 0,%r20,intr_restore /* backward */
	nop

	copy	%r0, %r24			/* unsigned long in_syscall */
	copy	%r16, %r25			/* struct pt_regs *regs */
#ifdef CONFIG_64BIT
	ldo	-16(%r30),%r29			/* Reference param save area */
#endif

	BL	do_signal,%r2
	copy	%r0, %r26			/* sigset_t *oldset = NULL */

	b	intr_check_sig
	nop

	/*
	 * External interrupts.
	 */

intr_extint:
	CMPIB=,n 0,%r16,1f
	get_stack_use_cr30
	b,n 3f

1:
#if 0  /* Interrupt Stack support not working yet! */
	mfctl	%cr31,%r1
	copy	%r30,%r17
	/* FIXME! depi below has hardcoded idea of interrupt stack size (32k)*/
#ifdef CONFIG_64BIT
	depdi	0,63,15,%r17
#else
	depi	0,31,15,%r17
#endif
	CMPB=,n	%r1,%r17,2f
	get_stack_use_cr31
	b,n 3f
#endif
2:
	get_stack_use_r30

3:
	save_specials	%r29
	virt_map
	save_general	%r29

	ldo	PT_FR0(%r29), %r24
	save_fp	%r24
	
	loadgp

	copy	%r29, %r26	/* arg0 is pt_regs */
	copy	%r29, %r16	/* save pt_regs */

	ldil	L%intr_return, %r2

#ifdef CONFIG_64BIT
	ldo	-16(%r30),%r29	/* Reference param save area */
#endif

	b	do_cpu_irq_mask
	ldo	R%intr_return(%r2), %r2	/* return to intr_return, not here */


	/* Generic interruptions (illegal insn, unaligned, page fault, etc) */

	.export         intr_save, code /* for os_hpmc */

intr_save:
	mfsp    %sr7,%r16
	CMPIB=,n 0,%r16,1f
	get_stack_use_cr30
	b	2f
	copy    %r8,%r26

1:
	get_stack_use_r30
	copy    %r8,%r26

2:
	save_specials	%r29

	/* If this trap is a itlb miss, skip saving/adjusting isr/ior */

	/*
	 * FIXME: 1) Use a #define for the hardwired "6" below (and in
	 *           traps.c.
	 *        2) Once we start executing code above 4 Gb, we need
	 *           to adjust iasq/iaoq here in the same way we
	 *           adjust isr/ior below.
	 */

	CMPIB=,n        6,%r26,skip_save_ior


	mfctl           %cr20, %r16 /* isr */
	nop		/* serialize mfctl on PA 2.0 to avoid 4 cycle penalty */
	mfctl           %cr21, %r17 /* ior */


#ifdef CONFIG_64BIT
	/*
	 * If the interrupted code was running with W bit off (32 bit),
	 * clear the b bits (bits 0 & 1) in the ior.
	 * save_specials left ipsw value in r8 for us to test.
	 */
	extrd,u,*<>     %r8,PSW_W_BIT,1,%r0
	depdi           0,1,2,%r17

	/*
	 * FIXME: This code has hardwired assumptions about the split
	 *        between space bits and offset bits. This will change
	 *        when we allow alternate page sizes.
	 */

	/* adjust isr/ior. */

	extrd,u         %r16,63,7,%r1    /* get high bits from isr for ior */
	depd            %r1,31,7,%r17    /* deposit them into ior */
	depdi           0,63,7,%r16      /* clear them from isr */
#endif
	STREG           %r16, PT_ISR(%r29)
	STREG           %r17, PT_IOR(%r29)


skip_save_ior:
	virt_map
	save_general	%r29

	ldo		PT_FR0(%r29), %r25
	save_fp		%r25
	
	loadgp

	copy		%r29, %r25	/* arg1 is pt_regs */
#ifdef CONFIG_64BIT
	ldo		-16(%r30),%r29	/* Reference param save area */
#endif

	ldil		L%intr_check_sig, %r2
	copy		%r25, %r16	/* save pt_regs */

	b		handle_interruption
	ldo		R%intr_check_sig(%r2), %r2


	/*
	 * Note for all tlb miss handlers:
	 *
	 * cr24 contains a pointer to the kernel address space
	 * page directory.
	 *