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Blackfin: fix data cache flushing when doing icache flushing

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Make sure we flush all data caches and their write buffers before flushing
icache, otherwise random edge cases could crop up where stale data is read
into icache from external memory.  As fallout, punt the combined icache +
dcache flush function since we cannot safely do them back to back -- the
SSYNC is needed between the dcache flush and the icache flush.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
This commit is contained in:
Mike Frysinger 2009-04-10 20:52:08 +00:00
parent f82e0a0c67
commit 5d89137a17
3 changed files with 16 additions and 36 deletions
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35
arch/blackfin/include/asm/cacheflush.h
View File

@ -30,7 +30,8 @@
#ifndef _BLACKFIN_CACHEFLUSH_H
#define _BLACKFIN_CACHEFLUSH_H
extern void blackfin_icache_dcache_flush_range(unsigned long start_address, unsigned long end_address);
#include <asm/blackfin.h> /* for SSYNC() */
extern void blackfin_icache_flush_range(unsigned long start_address, unsigned long end_address);
extern void blackfin_dcache_flush_range(unsigned long start_address, unsigned long end_address);
extern void blackfin_dcache_invalidate_range(unsigned long start_address, unsigned long end_address);
@ -54,32 +55,28 @@ extern void blackfin_invalidate_entire_dcache(void);
static inline void flush_icache_range(unsigned start, unsigned end)
{
#if defined(CONFIG_BFIN_DCACHE) && defined(CONFIG_BFIN_ICACHE)
#if defined(CONFIG_BFIN_WB)
blackfin_dcache_flush_range(start, end);
#endif
# if defined(CONFIG_BFIN_WT)
blackfin_icache_flush_range((start), (end));
/* Make sure all write buffers in the data side of the core
* are flushed before trying to invalidate the icache. This
* needs to be after the data flush and before the icache
* flush so that the SSYNC does the right thing in preventing
* the instruction prefetcher from hitting things in cached
* memory at the wrong time -- it runs much further ahead than
* the pipeline.
*/
SSYNC();
#if defined(CONFIG_BFIN_ICACHE)
blackfin_icache_flush_range(start, end);
flush_icache_range_others(start, end);
# else
blackfin_icache_dcache_flush_range((start), (end));
# endif
#else
# if defined(CONFIG_BFIN_ICACHE)
blackfin_icache_flush_range((start), (end));
flush_icache_range_others(start, end);
# endif
# if defined(CONFIG_BFIN_DCACHE)
blackfin_dcache_flush_range((start), (end));
# endif
#endif
}
#define copy_to_user_page(vma, page, vaddr, dst, src, len) \
do { memcpy(dst, src, len); \
flush_icache_range((unsigned) (dst), (unsigned) (dst) + (len)); \
flush_icache_range_others((unsigned long) (dst), (unsigned long) (dst) + (len));\
} while (0)
#define copy_from_user_page(vma, page, vaddr, dst, src, len) memcpy(dst, src, len)

1
arch/blackfin/kernel/bfin_ksyms.c
View File

@ -16,7 +16,6 @@ EXPORT_SYMBOL(bfin_return_from_exception);
/* All the Blackfin cache functions: mach-common/cache.S */
EXPORT_SYMBOL(blackfin_dcache_invalidate_range);
EXPORT_SYMBOL(blackfin_icache_dcache_flush_range);
EXPORT_SYMBOL(blackfin_icache_flush_range);
EXPORT_SYMBOL(blackfin_dcache_flush_range);
EXPORT_SYMBOL(blackfin_dflush_page);

16
arch/blackfin/mach-common/cache.S
View File

@ -80,22 +80,6 @@ ENTRY(_blackfin_icache_flush_range)
do_flush IFLUSH, , nop
ENDPROC(_blackfin_icache_flush_range)
/* Flush all cache lines assocoiated with this area of memory. */
ENTRY(_blackfin_icache_dcache_flush_range)
/*
* Walkaround to avoid loading wrong instruction after invalidating icache
* and following sequence is met.
*
* 1) One instruction address is cached in the instruction cache.
* 2) This instruction in SDRAM is changed.
* 3) IFLASH[P0] is executed only once in blackfin_icache_flush_range().
* 4) This instruction is executed again, but the old one is loaded.
*/
P0 = R0;
IFLUSH[P0];
do_flush FLUSH, IFLUSH
ENDPROC(_blackfin_icache_dcache_flush_range)
/* Throw away all D-cached data in specified region without any obligation to
* write them back. Since the Blackfin ISA does not have an "invalidate"
* instruction, we use flush/invalidate. Perhaps as a speed optimization we