linux/arch/arm64/mm/cache.S
Catalin Marinas c218bca74e arm64: Relax the kernel cache requirements for boot
With system caches for the host OS or architected caches for guest OS we
cannot easily guarantee that there are no dirty or stale cache lines for
the areas of memory written by the kernel during boot with the MMU off
(therefore non-cacheable accesses).

This patch adds the necessary cache maintenance during boot and relaxes
the booting requirements.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
2014-04-05 10:06:18 +01:00

256 lines
6.3 KiB
ArmAsm

/*
* Cache maintenance
*
* Copyright (C) 2001 Deep Blue Solutions Ltd.
* Copyright (C) 2012 ARM Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/linkage.h>
#include <linux/init.h>
#include <asm/assembler.h>
#include "proc-macros.S"
/*
* __flush_dcache_all()
*
* Flush the whole D-cache.
*
* Corrupted registers: x0-x7, x9-x11
*/
__flush_dcache_all:
dsb sy // ensure ordering with previous memory accesses
mrs x0, clidr_el1 // read clidr
and x3, x0, #0x7000000 // extract loc from clidr
lsr x3, x3, #23 // left align loc bit field
cbz x3, finished // if loc is 0, then no need to clean
mov x10, #0 // start clean at cache level 0
loop1:
add x2, x10, x10, lsr #1 // work out 3x current cache level
lsr x1, x0, x2 // extract cache type bits from clidr
and x1, x1, #7 // mask of the bits for current cache only
cmp x1, #2 // see what cache we have at this level
b.lt skip // skip if no cache, or just i-cache
save_and_disable_irqs x9 // make CSSELR and CCSIDR access atomic
msr csselr_el1, x10 // select current cache level in csselr
isb // isb to sych the new cssr&csidr
mrs x1, ccsidr_el1 // read the new ccsidr
restore_irqs x9
and x2, x1, #7 // extract the length of the cache lines
add x2, x2, #4 // add 4 (line length offset)
mov x4, #0x3ff
and x4, x4, x1, lsr #3 // find maximum number on the way size
clz w5, w4 // find bit position of way size increment
mov x7, #0x7fff
and x7, x7, x1, lsr #13 // extract max number of the index size
loop2:
mov x9, x4 // create working copy of max way size
loop3:
lsl x6, x9, x5
orr x11, x10, x6 // factor way and cache number into x11
lsl x6, x7, x2
orr x11, x11, x6 // factor index number into x11
dc cisw, x11 // clean & invalidate by set/way
subs x9, x9, #1 // decrement the way
b.ge loop3
subs x7, x7, #1 // decrement the index
b.ge loop2
skip:
add x10, x10, #2 // increment cache number
cmp x3, x10
b.gt loop1
finished:
mov x10, #0 // swith back to cache level 0
msr csselr_el1, x10 // select current cache level in csselr
dsb sy
isb
ret
ENDPROC(__flush_dcache_all)
/*
* flush_cache_all()
*
* Flush the entire cache system. The data cache flush is now achieved
* using atomic clean / invalidates working outwards from L1 cache. This
* is done using Set/Way based cache maintainance instructions. The
* instruction cache can still be invalidated back to the point of
* unification in a single instruction.
*/
ENTRY(flush_cache_all)
mov x12, lr
bl __flush_dcache_all
mov x0, #0
ic ialluis // I+BTB cache invalidate
ret x12
ENDPROC(flush_cache_all)
/*
* flush_icache_range(start,end)
*
* Ensure that the I and D caches are coherent within specified region.
* This is typically used when code has been written to a memory region,
* and will be executed.
*
* - start - virtual start address of region
* - end - virtual end address of region
*/
ENTRY(flush_icache_range)
/* FALLTHROUGH */
/*
* __flush_cache_user_range(start,end)
*
* Ensure that the I and D caches are coherent within specified region.
* This is typically used when code has been written to a memory region,
* and will be executed.
*
* - start - virtual start address of region
* - end - virtual end address of region
*/
ENTRY(__flush_cache_user_range)
dcache_line_size x2, x3
sub x3, x2, #1
bic x4, x0, x3
1:
USER(9f, dc cvau, x4 ) // clean D line to PoU
add x4, x4, x2
cmp x4, x1
b.lo 1b
dsb sy
icache_line_size x2, x3
sub x3, x2, #1
bic x4, x0, x3
1:
USER(9f, ic ivau, x4 ) // invalidate I line PoU
add x4, x4, x2
cmp x4, x1
b.lo 1b
9: // ignore any faulting cache operation
dsb sy
isb
ret
ENDPROC(flush_icache_range)
ENDPROC(__flush_cache_user_range)
/*
* __flush_dcache_area(kaddr, size)
*
* Ensure that the data held in the page kaddr is written back to the
* page in question.
*
* - kaddr - kernel address
* - size - size in question
*/
ENTRY(__flush_dcache_area)
dcache_line_size x2, x3
add x1, x0, x1
sub x3, x2, #1
bic x0, x0, x3
1: dc civac, x0 // clean & invalidate D line / unified line
add x0, x0, x2
cmp x0, x1
b.lo 1b
dsb sy
ret
ENDPROC(__flush_dcache_area)
/*
* __inval_cache_range(start, end)
* - start - start address of region
* - end - end address of region
*/
ENTRY(__inval_cache_range)
/* FALLTHROUGH */
/*
* __dma_inv_range(start, end)
* - start - virtual start address of region
* - end - virtual end address of region
*/
__dma_inv_range:
dcache_line_size x2, x3
sub x3, x2, #1
bic x0, x0, x3
bic x1, x1, x3
1: dc ivac, x0 // invalidate D / U line
add x0, x0, x2
cmp x0, x1
b.lo 1b
dsb sy
ret
ENDPROC(__inval_cache_range)
ENDPROC(__dma_inv_range)
/*
* __dma_clean_range(start, end)
* - start - virtual start address of region
* - end - virtual end address of region
*/
__dma_clean_range:
dcache_line_size x2, x3
sub x3, x2, #1
bic x0, x0, x3
1: dc cvac, x0 // clean D / U line
add x0, x0, x2
cmp x0, x1
b.lo 1b
dsb sy
ret
ENDPROC(__dma_clean_range)
/*
* __dma_flush_range(start, end)
* - start - virtual start address of region
* - end - virtual end address of region
*/
ENTRY(__dma_flush_range)
dcache_line_size x2, x3
sub x3, x2, #1
bic x0, x0, x3
1: dc civac, x0 // clean & invalidate D / U line
add x0, x0, x2
cmp x0, x1
b.lo 1b
dsb sy
ret
ENDPROC(__dma_flush_range)
/*
* __dma_map_area(start, size, dir)
* - start - kernel virtual start address
* - size - size of region
* - dir - DMA direction
*/
ENTRY(__dma_map_area)
add x1, x1, x0
cmp w2, #DMA_FROM_DEVICE
b.eq __dma_inv_range
b __dma_clean_range
ENDPROC(__dma_map_area)
/*
* __dma_unmap_area(start, size, dir)
* - start - kernel virtual start address
* - size - size of region
* - dir - DMA direction
*/
ENTRY(__dma_unmap_area)
add x1, x1, x0
cmp w2, #DMA_TO_DEVICE
b.ne __dma_inv_range
ret
ENDPROC(__dma_unmap_area)