6ebbf2ce43
ARMv6 and greater introduced a new instruction ("bx") which can be used
to return from function calls. Recent CPUs perform better when the
"bx lr" instruction is used rather than the "mov pc, lr" instruction,
and this sequence is strongly recommended to be used by the ARM
architecture manual (section A.4.1.1).
We provide a new macro "ret" with all its variants for the condition
code which will resolve to the appropriate instruction.
Rather than doing this piecemeal, and miss some instances, change all
the "mov pc" instances to use the new macro, with the exception of
the "movs" instruction and the kprobes code. This allows us to detect
the "mov pc, lr" case and fix it up - and also gives us the possibility
of deploying this for other registers depending on the CPU selection.
Reported-by: Will Deacon <will.deacon@arm.com>
Tested-by: Stephen Warren <swarren@nvidia.com> # Tegra Jetson TK1
Tested-by: Robert Jarzmik <robert.jarzmik@free.fr> # mioa701_bootresume.S
Tested-by: Andrew Lunn <andrew@lunn.ch> # Kirkwood
Tested-by: Shawn Guo <shawn.guo@freescale.com>
Tested-by: Tony Lindgren <tony@atomide.com> # OMAPs
Tested-by: Gregory CLEMENT <gregory.clement@free-electrons.com> # Armada XP, 375, 385
Acked-by: Sekhar Nori <nsekhar@ti.com> # DaVinci
Acked-by: Christoffer Dall <christoffer.dall@linaro.org> # kvm/hyp
Acked-by: Haojian Zhuang <haojian.zhuang@gmail.com> # PXA3xx
Acked-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> # Xen
Tested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> # ARMv7M
Tested-by: Simon Horman <horms+renesas@verge.net.au> # Shmobile
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
207 lines
4.7 KiB
ArmAsm
207 lines
4.7 KiB
ArmAsm
/*
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* linux/arch/arm/mm/cache-v4wt.S
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*
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* Copyright (C) 1997-2002 Russell king
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* ARMv4 write through cache operations support.
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*
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* We assume that the write buffer is not enabled.
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*/
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#include <linux/linkage.h>
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#include <linux/init.h>
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#include <asm/assembler.h>
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#include <asm/page.h>
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#include "proc-macros.S"
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/*
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* The size of one data cache line.
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*/
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#define CACHE_DLINESIZE 32
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/*
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* The number of data cache segments.
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*/
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#define CACHE_DSEGMENTS 8
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/*
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* The number of lines in a cache segment.
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*/
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#define CACHE_DENTRIES 64
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/*
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* This is the size at which it becomes more efficient to
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* clean the whole cache, rather than using the individual
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* cache line maintenance instructions.
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*
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* *** This needs benchmarking
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*/
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#define CACHE_DLIMIT 16384
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/*
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* flush_icache_all()
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*
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* Unconditionally clean and invalidate the entire icache.
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*/
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ENTRY(v4wt_flush_icache_all)
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mov r0, #0
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mcr p15, 0, r0, c7, c5, 0 @ invalidate I cache
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ret lr
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ENDPROC(v4wt_flush_icache_all)
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/*
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* flush_user_cache_all()
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*
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* Invalidate all cache entries in a particular address
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* space.
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*/
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ENTRY(v4wt_flush_user_cache_all)
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/* FALLTHROUGH */
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/*
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* flush_kern_cache_all()
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*
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* Clean and invalidate the entire cache.
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*/
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ENTRY(v4wt_flush_kern_cache_all)
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mov r2, #VM_EXEC
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mov ip, #0
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__flush_whole_cache:
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tst r2, #VM_EXEC
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mcrne p15, 0, ip, c7, c5, 0 @ invalidate I cache
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mcr p15, 0, ip, c7, c6, 0 @ invalidate D cache
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ret lr
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/*
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* flush_user_cache_range(start, end, flags)
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*
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* Clean and invalidate a range of cache entries in the specified
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* address space.
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*
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* - start - start address (inclusive, page aligned)
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* - end - end address (exclusive, page aligned)
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* - flags - vma_area_struct flags describing address space
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*/
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ENTRY(v4wt_flush_user_cache_range)
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sub r3, r1, r0 @ calculate total size
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cmp r3, #CACHE_DLIMIT
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bhs __flush_whole_cache
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1: mcr p15, 0, r0, c7, c6, 1 @ invalidate D entry
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tst r2, #VM_EXEC
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mcrne p15, 0, r0, c7, c5, 1 @ invalidate I entry
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add r0, r0, #CACHE_DLINESIZE
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cmp r0, r1
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blo 1b
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ret lr
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/*
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* coherent_kern_range(start, end)
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*
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* Ensure coherency between the Icache and the Dcache in the
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* region described by start. If you have non-snooping
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* Harvard caches, you need to implement this function.
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*
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* - start - virtual start address
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* - end - virtual end address
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*/
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ENTRY(v4wt_coherent_kern_range)
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/* FALLTRHOUGH */
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/*
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* coherent_user_range(start, end)
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*
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* Ensure coherency between the Icache and the Dcache in the
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* region described by start. If you have non-snooping
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* Harvard caches, you need to implement this function.
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*
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* - start - virtual start address
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* - end - virtual end address
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*/
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ENTRY(v4wt_coherent_user_range)
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bic r0, r0, #CACHE_DLINESIZE - 1
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1: mcr p15, 0, r0, c7, c5, 1 @ invalidate I entry
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add r0, r0, #CACHE_DLINESIZE
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cmp r0, r1
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blo 1b
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mov r0, #0
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ret lr
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/*
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* flush_kern_dcache_area(void *addr, size_t size)
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*
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* Ensure no D cache aliasing occurs, either with itself or
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* the I cache
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*
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* - addr - kernel address
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* - size - region size
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*/
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ENTRY(v4wt_flush_kern_dcache_area)
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mov r2, #0
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mcr p15, 0, r2, c7, c5, 0 @ invalidate I cache
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add r1, r0, r1
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/* fallthrough */
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/*
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* dma_inv_range(start, end)
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*
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* Invalidate (discard) the specified virtual address range.
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* May not write back any entries. If 'start' or 'end'
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* are not cache line aligned, those lines must be written
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* back.
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*
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* - start - virtual start address
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* - end - virtual end address
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*/
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v4wt_dma_inv_range:
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bic r0, r0, #CACHE_DLINESIZE - 1
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1: mcr p15, 0, r0, c7, c6, 1 @ invalidate D entry
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add r0, r0, #CACHE_DLINESIZE
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cmp r0, r1
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blo 1b
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ret lr
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/*
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* dma_flush_range(start, end)
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*
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* Clean and invalidate the specified virtual address range.
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*
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* - start - virtual start address
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* - end - virtual end address
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*/
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.globl v4wt_dma_flush_range
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.equ v4wt_dma_flush_range, v4wt_dma_inv_range
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/*
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* dma_unmap_area(start, size, dir)
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* - start - kernel virtual start address
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* - size - size of region
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* - dir - DMA direction
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*/
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ENTRY(v4wt_dma_unmap_area)
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add r1, r1, r0
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teq r2, #DMA_TO_DEVICE
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bne v4wt_dma_inv_range
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/* FALLTHROUGH */
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/*
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* dma_map_area(start, size, dir)
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* - start - kernel virtual start address
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* - size - size of region
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* - dir - DMA direction
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*/
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ENTRY(v4wt_dma_map_area)
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ret lr
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ENDPROC(v4wt_dma_unmap_area)
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ENDPROC(v4wt_dma_map_area)
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.globl v4wt_flush_kern_cache_louis
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.equ v4wt_flush_kern_cache_louis, v4wt_flush_kern_cache_all
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__INITDATA
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@ define struct cpu_cache_fns (see <asm/cacheflush.h> and proc-macros.S)
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define_cache_functions v4wt
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