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13 August 2024, 17:29:01 UTC
Revision 070e76cb3ffe43f6855492e77c96680c562598f0 authored by Leonid Yegoshin on 27 November 2014, 11:13:08 UTC, committed by Ralf Baechle on 27 November 2014, 16:21:56 UTC 
MIPS: tlbex: Fix potential HTW race on TLBL/M/S handlers
 
There is a potential race when probing the TLB in TLBL/M/S exception
handlers for a matching entry. Between the time we hit a TLBL/S/M
exception and the time we get to execute the TLBP instruction, the
HTW may have replaced the TLB entry we are interested in hence the TLB
probe may fail. However, in the existing handlers, we never checked the
status of the TLBP (ie check the result in the C0/Index register). We
fix this by adding such a check when the core implements the HTW. If
we couldn't find a matching entry, we return back and try again.

Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: <stable@vger.kernel.org> # v3.17+
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/8599/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
1 parent b4da18b
Raw File
Tip revision: 070e76cb3ffe43f6855492e77c96680c562598f0 authored by Leonid Yegoshin on 27 November 2014, 11:13:08 UTC
MIPS: tlbex: Fix potential HTW race on TLBL/M/S handlers
Tip revision: 070e76c
blk-mq-tag.h 
#ifndef INT_BLK_MQ_TAG_H
#define INT_BLK_MQ_TAG_H

#include "blk-mq.h"

enum {
	BT_WAIT_QUEUES	= 8,
	BT_WAIT_BATCH	= 8,
};

struct bt_wait_state {
	atomic_t wait_cnt;
	wait_queue_head_t wait;
} ____cacheline_aligned_in_smp;

#define TAG_TO_INDEX(bt, tag)	((tag) >> (bt)->bits_per_word)
#define TAG_TO_BIT(bt, tag)	((tag) & ((1 << (bt)->bits_per_word) - 1))

struct blk_mq_bitmap_tags {
	unsigned int depth;
	unsigned int wake_cnt;
	unsigned int bits_per_word;

	unsigned int map_nr;
	struct blk_align_bitmap *map;

	atomic_t wake_index;
	struct bt_wait_state *bs;
};

/*
 * Tag address space map.
 */
struct blk_mq_tags {
	unsigned int nr_tags;
	unsigned int nr_reserved_tags;

	atomic_t active_queues;

	struct blk_mq_bitmap_tags bitmap_tags;
	struct blk_mq_bitmap_tags breserved_tags;

	struct request **rqs;
	struct list_head page_list;
};


extern struct blk_mq_tags *blk_mq_init_tags(unsigned int nr_tags, unsigned int reserved_tags, int node);
extern void blk_mq_free_tags(struct blk_mq_tags *tags);

extern unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data);
extern void blk_mq_put_tag(struct blk_mq_hw_ctx *hctx, unsigned int tag, unsigned int *last_tag);
extern bool blk_mq_has_free_tags(struct blk_mq_tags *tags);
extern ssize_t blk_mq_tag_sysfs_show(struct blk_mq_tags *tags, char *page);
extern void blk_mq_tag_init_last_tag(struct blk_mq_tags *tags, unsigned int *last_tag);
extern int blk_mq_tag_update_depth(struct blk_mq_tags *tags, unsigned int depth);

enum {
	BLK_MQ_TAG_CACHE_MIN	= 1,
	BLK_MQ_TAG_CACHE_MAX	= 64,
};

enum {
	BLK_MQ_TAG_FAIL		= -1U,
	BLK_MQ_TAG_MIN		= BLK_MQ_TAG_CACHE_MIN,
	BLK_MQ_TAG_MAX		= BLK_MQ_TAG_FAIL - 1,
};

extern bool __blk_mq_tag_busy(struct blk_mq_hw_ctx *);
extern void __blk_mq_tag_idle(struct blk_mq_hw_ctx *);

static inline bool blk_mq_tag_busy(struct blk_mq_hw_ctx *hctx)
{
	if (!(hctx->flags & BLK_MQ_F_TAG_SHARED))
		return false;

	return __blk_mq_tag_busy(hctx);
}

static inline void blk_mq_tag_idle(struct blk_mq_hw_ctx *hctx)
{
	if (!(hctx->flags & BLK_MQ_F_TAG_SHARED))
		return;

	__blk_mq_tag_idle(hctx);
}

#endif
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