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Commit 684bd614 authored by Jeremy Kerr's avatar Jeremy Kerr Committed by Arnd Bergmann
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[POWERPC] cell: handle SPE kernel mappings that cross segment boundaries 



Currently, we have a possibilty that the SLBs setup during context
switch don't cover the entirety of the necessary lscsa and code
regions, if these regions cross a segment boundary.

This change checks the start and end of each region, and inserts a SLB
entry for each, if unique. We also remove the assumption that the
spu_save_code and spu_restore_code reside in the same segment, by using
the specific code array for save and restore.

Signed-off-by: default avatarJeremy Kerr <jk@ozlabs.org>
Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
parent f6eb7d7f

arch/powerpc/platforms/cell/spu_base.c

+43 −7
Original line number Diff line number Diff line
@@ -274,20 +274,56 @@ static void __spu_kernel_slb(void *addr, struct spu_slb *slb) 
	slb->esid = (ea & ESID_MASK) | SLB_ESID_V;

}



/**

 * Given an array of @nr_slbs SLB entries, @slbs, return non-zero if the

 * address @new_addr is present.

 */

static inline int __slb_present(struct spu_slb *slbs, int nr_slbs,

		void *new_addr)

{

	unsigned long ea = (unsigned long)new_addr;

	int i;



	for (i = 0; i < nr_slbs; i++)

		if (!((slbs[i].esid ^ ea) & ESID_MASK))

			return 1;



	return 0;

}



/**

 * Setup the SPU kernel SLBs, in preparation for a context save/restore. We

 * need to map both the context save area, and the save/restore code.

 *

 * Because the lscsa and code may cross segment boundaires, we check to see

 * if mappings are required for the start and end of each range. We currently

 * assume that the mappings are smaller that one segment - if not, something

 * is seriously wrong.

 */

void spu_setup_kernel_slbs(struct spu *spu, struct spu_lscsa *lscsa, void *code)

void spu_setup_kernel_slbs(struct spu *spu, struct spu_lscsa *lscsa,

		void *code, int code_size)

{

	struct spu_slb code_slb, lscsa_slb;

	struct spu_slb slbs[4];

	int i, nr_slbs = 0;

	/* start and end addresses of both mappings */

	void *addrs[] = {

		lscsa, (void *)lscsa + sizeof(*lscsa) - 1,

		code, code + code_size - 1

	};



	/* check the set of addresses, and create a new entry in the slbs array

	 * if there isn't already a SLB for that address */

	for (i = 0; i < ARRAY_SIZE(addrs); i++) {

		if (__slb_present(slbs, nr_slbs, addrs[i]))

			continue;



	__spu_kernel_slb(lscsa, &lscsa_slb);

	__spu_kernel_slb(code, &code_slb);

		__spu_kernel_slb(addrs[i], &slbs[nr_slbs]);

		nr_slbs++;

	}



	spu_load_slb(spu, 0, &lscsa_slb);

	if (lscsa_slb.esid != code_slb.esid)

		spu_load_slb(spu, 1, &code_slb);

	/* Add the set of SLBs */

	for (i = 0; i < nr_slbs; i++)

		spu_load_slb(spu, i, &slbs[i]);

}

EXPORT_SYMBOL_GPL(spu_setup_kernel_slbs);

arch/powerpc/platforms/cell/spufs/switch.c

+7 −4
Original line number Diff line number Diff line
@@ -691,7 +691,8 @@ static inline void resume_mfc_queue(struct spu_state *csa, struct spu *spu) 
	out_be64(&priv2->mfc_control_RW, MFC_CNTL_RESUME_DMA_QUEUE);

}



static inline void setup_mfc_slbs(struct spu_state *csa, struct spu *spu)

static inline void setup_mfc_slbs(struct spu_state *csa, struct spu *spu,

		unsigned int *code, int code_size)

{

	/* Save, Step 47:

	 * Restore, Step 30.
@@ -708,7 +709,7 @@ static inline void setup_mfc_slbs(struct spu_state *csa, struct spu *spu) 
	 *     translation is desired by OS environment).

	 */

	spu_invalidate_slbs(spu);

	spu_setup_kernel_slbs(spu, csa->lscsa, &spu_save_code);

	spu_setup_kernel_slbs(spu, csa->lscsa, code, code_size);

}



static inline void set_switch_active(struct spu_state *csa, struct spu *spu)
@@ -1835,7 +1836,8 @@ static void save_lscsa(struct spu_state *prev, struct spu *spu) 
	 */



	resume_mfc_queue(prev, spu);	/* Step 46. */

	setup_mfc_slbs(prev, spu);	/* Step 47. */

	/* Step 47. */

	setup_mfc_slbs(prev, spu, spu_save_code, sizeof(spu_save_code));

	set_switch_active(prev, spu);	/* Step 48. */

	enable_interrupts(prev, spu);	/* Step 49. */

	save_ls_16kb(prev, spu);	/* Step 50. */
@@ -1940,7 +1942,8 @@ static void restore_lscsa(struct spu_state *next, struct spu *spu) 
	setup_spu_status_part1(next, spu);	/* Step 27. */

	setup_spu_status_part2(next, spu);	/* Step 28. */

	restore_mfc_rag(next, spu);	        /* Step 29. */

	setup_mfc_slbs(next, spu);	        /* Step 30. */

	/* Step 30. */

	setup_mfc_slbs(next, spu, spu_restore_code, sizeof(spu_restore_code));

	set_spu_npc(next, spu);	                /* Step 31. */

	set_signot1(next, spu);	                /* Step 32. */

	set_signot2(next, spu);	                /* Step 33. */

include/asm-powerpc/spu.h

+2 −2
Original line number Diff line number Diff line
@@ -201,8 +201,8 @@ int spu_irq_class_0_bottom(struct spu *spu); 
int spu_irq_class_1_bottom(struct spu *spu);

void spu_irq_setaffinity(struct spu *spu, int cpu);



void spu_setup_kernel_slbs(struct spu *spu,

		struct spu_lscsa *lscsa, void *code);

void spu_setup_kernel_slbs(struct spu *spu, struct spu_lscsa *lscsa,

		void *code, int code_size);



#ifdef CONFIG_KEXEC

void crash_register_spus(struct list_head *list);