linux/arch/blackfin/mach-common/cache.S
Sonic Zhang d7ff1a90b2 Blackfin arch: Fix bug - KGDB single step into the middle of a 4 bytes instruction on bf561 after soft bp is hit
Run IFLUSH twice to avoid loading wrong instruction
after invalidating icache and following sequence is met.

1) The one instruction address is cached in the icache.
2) This instruction in SDRAM is changed.
3) IFLASH[P0] is executed only once in lackfin_icache_flush_range().
4) This instruction is executed again, but not the changed new one.

Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
2009-03-05 18:26:59 +08:00

122 lines
3.2 KiB
ArmAsm

/*
* Blackfin cache control code
*
* Copyright 2004-2008 Analog Devices Inc.
*
* Enter bugs at http://blackfin.uclinux.org/
*
* Licensed under the GPL-2 or later.
*/
#include <linux/linkage.h>
#include <asm/blackfin.h>
#include <asm/cache.h>
#include <asm/page.h>
.text
/* Since all L1 caches work the same way, we use the same method for flushing
* them. Only the actual flush instruction differs. We write this in asm as
* GCC can be hard to coax into writing nice hardware loops.
*
* Also, we assume the following register setup:
* R0 = start address
* R1 = end address
*/
.macro do_flush flushins:req optflushins optnopins label
R2 = -L1_CACHE_BYTES;
/* start = (start & -L1_CACHE_BYTES) */
R0 = R0 & R2;
/* end = ((end - 1) & -L1_CACHE_BYTES) + L1_CACHE_BYTES; */
R1 += -1;
R1 = R1 & R2;
R1 += L1_CACHE_BYTES;
/* count = (end - start) >> L1_CACHE_SHIFT */
R2 = R1 - R0;
R2 >>= L1_CACHE_SHIFT;
P1 = R2;
.ifnb \label
\label :
.endif
P0 = R0;
LSETUP (1f, 2f) LC1 = P1;
1:
.ifnb \optflushins
\optflushins [P0];
.endif
#if ANOMALY_05000443
.ifb \optnopins
2:
.endif
\flushins [P0++];
.ifnb \optnopins
2: \optnopins;
.endif
#else
2: \flushins [P0++];
#endif
RTS;
.endm
/* Invalidate all instruction cache lines assocoiated with this memory area */
ENTRY(_blackfin_icache_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 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
* could bang on the DTEST MMRs ...
*/
ENTRY(_blackfin_dcache_invalidate_range)
do_flush FLUSHINV
ENDPROC(_blackfin_dcache_invalidate_range)
/* Flush all data cache lines assocoiated with this memory area */
ENTRY(_blackfin_dcache_flush_range)
do_flush FLUSH, , , .Ldfr
ENDPROC(_blackfin_dcache_flush_range)
/* Our headers convert the page structure to an address, so just need to flush
* its contents like normal. We know the start address is page aligned (which
* greater than our cache alignment), as is the end address. So just jump into
* the middle of the dcache flush function.
*/
ENTRY(_blackfin_dflush_page)
P1 = 1 << (PAGE_SHIFT - L1_CACHE_SHIFT);
jump .Ldfr;
ENDPROC(_blackfin_dflush_page)