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linux-next/arch/arm64/mm/cache.S
Will Deacon 3b8c9f1cdf arm64: IPI each CPU after invalidating the I-cache for kernel mappings
When invalidating the instruction cache for a kernel mapping via
flush_icache_range(), it is also necessary to flush the pipeline for
other CPUs so that instructions fetched into the pipeline before the
I-cache invalidation are discarded. For example, if module 'foo' is
unloaded and then module 'bar' is loaded into the same area of memory,
a CPU could end up executing instructions from 'foo' when branching into
'bar' if these instructions were fetched into the pipeline before 'foo'
was unloaded.

Whilst this is highly unlikely to occur in practice, particularly as
any exception acts as a context-synchronizing operation, following the
letter of the architecture requires us to execute an ISB on each CPU
in order for the new instruction stream to be visible.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
2018-07-05 17:24:36 +01:00

255 lines
5.8 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/errno.h>
#include <linux/linkage.h>
#include <linux/init.h>
#include <asm/assembler.h>
#include <asm/cpufeature.h>
#include <asm/alternative.h>
#include <asm/asm-uaccess.h>
/*
* 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)
uaccess_ttbr0_enable x2, x3, x4
alternative_if ARM64_HAS_CACHE_IDC
dsb ishst
b 7f
alternative_else_nop_endif
dcache_line_size x2, x3
sub x3, x2, #1
bic x4, x0, x3
1:
user_alt 9f, "dc cvau, x4", "dc civac, x4", ARM64_WORKAROUND_CLEAN_CACHE
add x4, x4, x2
cmp x4, x1
b.lo 1b
dsb ish
7:
alternative_if ARM64_HAS_CACHE_DIC
isb
b 8f
alternative_else_nop_endif
invalidate_icache_by_line x0, x1, x2, x3, 9f
8: mov x0, #0
1:
uaccess_ttbr0_disable x1, x2
ret
9:
mov x0, #-EFAULT
b 1b
ENDPROC(__flush_icache_range)
ENDPROC(__flush_cache_user_range)
/*
* invalidate_icache_range(start,end)
*
* Ensure that the I cache is invalid within specified region.
*
* - start - virtual start address of region
* - end - virtual end address of region
*/
ENTRY(invalidate_icache_range)
alternative_if ARM64_HAS_CACHE_DIC
mov x0, xzr
isb
ret
alternative_else_nop_endif
uaccess_ttbr0_enable x2, x3, x4
invalidate_icache_by_line x0, x1, x2, x3, 2f
mov x0, xzr
1:
uaccess_ttbr0_disable x1, x2
ret
2:
mov x0, #-EFAULT
b 1b
ENDPROC(invalidate_icache_range)
/*
* __flush_dcache_area(kaddr, size)
*
* Ensure that any D-cache lines for the interval [kaddr, kaddr+size)
* are cleaned and invalidated to the PoC.
*
* - kaddr - kernel address
* - size - size in question
*/
ENTRY(__flush_dcache_area)
dcache_by_line_op civac, sy, x0, x1, x2, x3
ret
ENDPIPROC(__flush_dcache_area)
/*
* __clean_dcache_area_pou(kaddr, size)
*
* Ensure that any D-cache lines for the interval [kaddr, kaddr+size)
* are cleaned to the PoU.
*
* - kaddr - kernel address
* - size - size in question
*/
ENTRY(__clean_dcache_area_pou)
alternative_if ARM64_HAS_CACHE_IDC
dsb ishst
ret
alternative_else_nop_endif
dcache_by_line_op cvau, ish, x0, x1, x2, x3
ret
ENDPROC(__clean_dcache_area_pou)
/*
* __inval_dcache_area(kaddr, size)
*
* Ensure that any D-cache lines for the interval [kaddr, kaddr+size)
* are invalidated. Any partial lines at the ends of the interval are
* also cleaned to PoC to prevent data loss.
*
* - kaddr - kernel address
* - size - size in question
*/
ENTRY(__inval_dcache_area)
/* FALLTHROUGH */
/*
* __dma_inv_area(start, size)
* - start - virtual start address of region
* - size - size in question
*/
__dma_inv_area:
add x1, x1, x0
dcache_line_size x2, x3
sub x3, x2, #1
tst x1, x3 // end cache line aligned?
bic x1, x1, x3
b.eq 1f
dc civac, x1 // clean & invalidate D / U line
1: tst x0, x3 // start cache line aligned?
bic x0, x0, x3
b.eq 2f
dc civac, x0 // clean & invalidate D / U line
b 3f
2: dc ivac, x0 // invalidate D / U line
3: add x0, x0, x2
cmp x0, x1
b.lo 2b
dsb sy
ret
ENDPIPROC(__inval_dcache_area)
ENDPROC(__dma_inv_area)
/*
* __clean_dcache_area_poc(kaddr, size)
*
* Ensure that any D-cache lines for the interval [kaddr, kaddr+size)
* are cleaned to the PoC.
*
* - kaddr - kernel address
* - size - size in question
*/
ENTRY(__clean_dcache_area_poc)
/* FALLTHROUGH */
/*
* __dma_clean_area(start, size)
* - start - virtual start address of region
* - size - size in question
*/
__dma_clean_area:
dcache_by_line_op cvac, sy, x0, x1, x2, x3
ret
ENDPIPROC(__clean_dcache_area_poc)
ENDPROC(__dma_clean_area)
/*
* __clean_dcache_area_pop(kaddr, size)
*
* Ensure that any D-cache lines for the interval [kaddr, kaddr+size)
* are cleaned to the PoP.
*
* - kaddr - kernel address
* - size - size in question
*/
ENTRY(__clean_dcache_area_pop)
dcache_by_line_op cvap, sy, x0, x1, x2, x3
ret
ENDPIPROC(__clean_dcache_area_pop)
/*
* __dma_flush_area(start, size)
*
* clean & invalidate D / U line
*
* - start - virtual start address of region
* - size - size in question
*/
ENTRY(__dma_flush_area)
dcache_by_line_op civac, sy, x0, x1, x2, x3
ret
ENDPIPROC(__dma_flush_area)
/*
* __dma_map_area(start, size, dir)
* - start - kernel virtual start address
* - size - size of region
* - dir - DMA direction
*/
ENTRY(__dma_map_area)
cmp w2, #DMA_FROM_DEVICE
b.eq __dma_inv_area
b __dma_clean_area
ENDPIPROC(__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)
cmp w2, #DMA_TO_DEVICE
b.ne __dma_inv_area
ret
ENDPIPROC(__dma_unmap_area)