Commit bcf0b088 authored by Kumar Gala's avatar Kumar Gala
Browse files

[POWERPC] Move to runtime allocated exception stacks 



For the additonal exception levels (critical, debug, machine check) on
40x/book-e we were using "static" allocations of the stack in the
associated head.S.

Move to a runtime allocation to make the code a bit easier to read as
we mimic how we handle IRQ stacks.  Its also a bit easier to setup the
stack with a "dummy" thread_info in C code.

Signed-off-by: default avatarKumar Gala <galak@kernel.crashing.org>
Acked-by: default avatarPaul Mackerras <paulus@samba.org>
parent c054065b

arch/powerpc/kernel/head_40x.S

+4 −14
Original line number Diff line number Diff line
@@ -148,14 +148,14 @@ _ENTRY(crit_r11) 
	mfcr	r10;			/* save CR in r10 for now	   */\

	mfspr	r11,SPRN_SRR3;		/* check whether user or kernel    */\

	andi.	r11,r11,MSR_PR;						     \

	lis	r11,critical_stack_top@h;				     \

	ori	r11,r11,critical_stack_top@l;				     \

	lis	r11,critirq_ctx@ha;					     \

	tophys(r11,r11);						     \

	lwz	r11,critirq_ctx@l(r11);					     \

	beq	1f;							     \

	/* COMING FROM USER MODE */					     \

	mfspr	r11,SPRN_SPRG3;		/* if from user, start at top of   */\

	lwz	r11,THREAD_INFO-THREAD(r11); /* this thread's kernel stack */\

	addi	r11,r11,THREAD_SIZE;					     \

1:	subi	r11,r11,INT_FRAME_SIZE;	/* Allocate an exception frame     */\

1:	addi	r11,r11,THREAD_SIZE-INT_FRAME_SIZE; /* Alloc an excpt frm  */\

	tophys(r11,r11);						     \

	stw	r10,_CCR(r11);          /* save various registers	   */\

	stw	r12,GPR12(r11);						     \
@@ -996,16 +996,6 @@ empty_zero_page: 
swapper_pg_dir:

	.space	PGD_TABLE_SIZE





/* Stack for handling critical exceptions from kernel mode */

	.section .bss

        .align 12

exception_stack_bottom:

	.space	4096

critical_stack_top:

	.globl	exception_stack_top

exception_stack_top:



/* Room for two PTE pointers, usually the kernel and current user pointers

 * to their respective root page table.

 */

arch/powerpc/kernel/head_44x.S

+0 −9
Original line number Diff line number Diff line
@@ -737,15 +737,6 @@ empty_zero_page: 
swapper_pg_dir:

	.space	PGD_TABLE_SIZE



/* Reserved 4k for the critical exception stack & 4k for the machine

 * check stack per CPU for kernel mode exceptions */

	.section .bss

        .align 12

exception_stack_bottom:

	.space	BOOKE_EXCEPTION_STACK_SIZE

	.globl	exception_stack_top

exception_stack_top:



/*

 * Room for two PTE pointers, usually the kernel and current user pointers

 * to their respective root page table.

arch/powerpc/kernel/head_booke.h

+11 −18
Original line number Diff line number Diff line
@@ -43,9 +43,7 @@ 
	SAVE_2GPRS(7, r11)



/* To handle the additional exception priority levels on 40x and Book-E

 * processors we allocate a 4k stack per additional priority level. The various

 * head_xxx.S files allocate space (exception_stack_top) for each priority's

 * stack times the number of CPUs

 * processors we allocate a stack per additional priority level.

 *

 * On 40x critical is the only additional level

 * On 44x/e500 we have critical and machine check
@@ -61,36 +59,31 @@ 
 * going to critical or their own debug level we aren't currently

 * providing configurations that micro-optimize space usage.

 */

#ifdef CONFIG_44x

#define NUM_EXCEPTION_LVLS	2

#else

#define NUM_EXCEPTION_LVLS	3

#endif

#define BOOKE_EXCEPTION_STACK_SIZE	(4096 * NUM_EXCEPTION_LVLS)



/* CRIT_SPRG only used in critical exception handling */

#define CRIT_SPRG	SPRN_SPRG2

/* MCHECK_SPRG only used in machine check exception handling */

#define MCHECK_SPRG	SPRN_SPRG6W



#define MCHECK_STACK_TOP	(exception_stack_top - 4096)

#define CRIT_STACK_TOP		(exception_stack_top)

#define MCHECK_STACK_BASE	mcheckirq_ctx

#define CRIT_STACK_BASE		critirq_ctx



/* only on e200 for now */

#define DEBUG_STACK_TOP		(exception_stack_top - 8192)

#define DEBUG_STACK_BASE	dbgirq_ctx

#define DEBUG_SPRG		SPRN_SPRG6W



#ifdef CONFIG_SMP

#define BOOKE_LOAD_EXC_LEVEL_STACK(level)		\

	mfspr	r8,SPRN_PIR;				\

	mulli	r8,r8,BOOKE_EXCEPTION_STACK_SIZE;	\

	neg	r8,r8;					\

	addis	r8,r8,level##_STACK_TOP@ha;		\

	addi	r8,r8,level##_STACK_TOP@l

	slwi	r8,r8,2;				\

	addis	r8,r8,level##_STACK_BASE@ha;		\

	lwz	r8,level##_STACK_BASE@l(r8);		\

	addi	r8,r8,THREAD_SIZE;

#else

#define BOOKE_LOAD_EXC_LEVEL_STACK(level)		\

	lis	r8,level##_STACK_TOP@h;			\

	ori	r8,r8,level##_STACK_TOP@l

	lis	r8,level##_STACK_BASE@ha;		\

	lwz	r8,level##_STACK_BASE@l(r8);		\

	addi	r8,r8,THREAD_SIZE;

#endif



/*

arch/powerpc/kernel/head_fsl_booke.S

+0 −9
Original line number Diff line number Diff line
@@ -1080,15 +1080,6 @@ empty_zero_page: 
swapper_pg_dir:

	.space	PGD_TABLE_SIZE



/* Reserved 4k for the critical exception stack & 4k for the machine

 * check stack per CPU for kernel mode exceptions */

	.section .bss

	.align 12

exception_stack_bottom:

	.space	BOOKE_EXCEPTION_STACK_SIZE * NR_CPUS

	.globl	exception_stack_top

exception_stack_top:



/*

 * Room for two PTE pointers, usually the kernel and current user pointers

 * to their respective root page table.

arch/powerpc/kernel/irq.c

+33 −0
Original line number Diff line number Diff line
@@ -356,9 +356,42 @@ void __init init_IRQ(void) 
{

	if (ppc_md.init_IRQ)

		ppc_md.init_IRQ();



	exc_lvl_ctx_init();



	irq_ctx_init();

}



#if defined(CONFIG_BOOKE) || defined(CONFIG_40x)

struct thread_info   *critirq_ctx[NR_CPUS] __read_mostly;

struct thread_info    *dbgirq_ctx[NR_CPUS] __read_mostly;

struct thread_info *mcheckirq_ctx[NR_CPUS] __read_mostly;



void exc_lvl_ctx_init(void)

{

	struct thread_info *tp;

	int i;



	for_each_possible_cpu(i) {

		memset((void *)critirq_ctx[i], 0, THREAD_SIZE);

		tp = critirq_ctx[i];

		tp->cpu = i;

		tp->preempt_count = 0;



#ifdef CONFIG_BOOKE

		memset((void *)dbgirq_ctx[i], 0, THREAD_SIZE);

		tp = dbgirq_ctx[i];

		tp->cpu = i;

		tp->preempt_count = 0;



		memset((void *)mcheckirq_ctx[i], 0, THREAD_SIZE);

		tp = mcheckirq_ctx[i];

		tp->cpu = i;

		tp->preempt_count = HARDIRQ_OFFSET;

#endif

	}

}

#endif



#ifdef CONFIG_IRQSTACKS

struct thread_info *softirq_ctx[NR_CPUS] __read_mostly;

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