031bd879f7
ARM v7 architecture introduced the concept of cache levels and related control registers. New processors like A7 and A15 embed an L2 unified cache controller that becomes part of the cache level hierarchy. Some operations in the kernel like cpu_suspend and __cpu_disable do not require a flush of the entire cache hierarchy to DRAM but just the cache levels belonging to the Level of Unification Inner Shareable (LoUIS), which in most of ARM v7 systems correspond to L1. The current cache flushing API used in cpu_suspend and __cpu_disable, flush_cache_all(), ends up flushing the whole cache hierarchy since for v7 it cleans and invalidates all cache levels up to Level of Coherency (LoC) which cripples system performance when used in hot paths like hotplug and cpuidle. Therefore a new kernel cache maintenance API must be added to cope with latest ARM system requirements. This patch adds flush_cache_louis() to the ARM kernel cache maintenance API. This function cleans and invalidates all data cache levels up to the Level of Unification Inner Shareable (LoUIS) and invalidates the instruction cache for processors that support it (> v7). This patch also creates an alias of the cache LoUIS function to flush_kern_all for all processor versions prior to v7, so that the current cache flushing behaviour is unchanged for those processors. v7 cache maintenance code implements a cache LoUIS function that cleans and invalidates the D-cache up to LoUIS and invalidates the I-cache, according to the new API. Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Reviewed-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Tested-by: Shawn Guo <shawn.guo@linaro.org>
205 lines
4.6 KiB
ArmAsm
205 lines
4.6 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/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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mov pc, 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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mov pc, 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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mov pc, 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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mov pc, 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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mov pc, 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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mov pc, 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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