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linux/arch/arm/mm/cache-v4.S
Linus Walleij 7b749aad1f ARM: 9393/1: mm: Use conditionals for CFI branches
Commit 9385/2 introduced a few branches inside function
prototypes when using CFI in order to deal with the situation
where CFI inserts a few bytes of function information in front
of the symbol.

This is not good for older CPUs where every cycle counts.

Commit 9386/2 alleviated the situation a bit by using aliases
for the cache functions with identical signatures.

This leaves the coherent cache flush functions
*_coherent_kern_range() with these branches to the corresponing
*_coherent_user_range() around, since their return type differ and
they therefore cannot be aliased.

Solve this by a simple ifdef so at least we can use fallthroughs
when compiling without CFI enabled.

Link: https://lore.kernel.org/linux-arm-kernel/Zi+e9M%2Ff5b%2FSto9H@shell.armlinux.org.uk/

Suggested-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
2024-05-07 10:30:24 +01:00

149 lines
3.3 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* linux/arch/arm/mm/cache-v4.S
*
* Copyright (C) 1997-2002 Russell king
*/
#include <linux/linkage.h>
#include <linux/init.h>
#include <linux/cfi_types.h>
#include <asm/assembler.h>
#include <asm/page.h>
#include "proc-macros.S"
/*
* flush_icache_all()
*
* Unconditionally clean and invalidate the entire icache.
*/
SYM_TYPED_FUNC_START(v4_flush_icache_all)
ret lr
SYM_FUNC_END(v4_flush_icache_all)
/*
* flush_user_cache_all()
*
* Invalidate all cache entries in a particular address
* space.
*
* - mm - mm_struct describing address space
*/
SYM_FUNC_ALIAS(v4_flush_user_cache_all, v4_flush_kern_cache_all)
/*
* flush_kern_cache_all()
*
* Clean and invalidate the entire cache.
*/
SYM_TYPED_FUNC_START(v4_flush_kern_cache_all)
#ifdef CONFIG_CPU_CP15
mov r0, #0
mcr p15, 0, r0, c7, c7, 0 @ flush ID cache
ret lr
#else
ret lr
#endif
SYM_FUNC_END(v4_flush_kern_cache_all)
/*
* flush_user_cache_range(start, end, flags)
*
* Invalidate a range of cache entries in the specified
* address space.
*
* - start - start address (may not be aligned)
* - end - end address (exclusive, may not be aligned)
* - flags - vma_area_struct flags describing address space
*/
SYM_TYPED_FUNC_START(v4_flush_user_cache_range)
#ifdef CONFIG_CPU_CP15
mov ip, #0
mcr p15, 0, ip, c7, c7, 0 @ flush ID cache
ret lr
#else
ret lr
#endif
SYM_FUNC_END(v4_flush_user_cache_range)
/*
* coherent_kern_range(start, end)
*
* Ensure coherency between the Icache and the Dcache in the
* region described by start. If you have non-snooping
* Harvard caches, you need to implement this function.
*
* - start - virtual start address
* - end - virtual end address
*/
SYM_TYPED_FUNC_START(v4_coherent_kern_range)
ret lr
SYM_FUNC_END(v4_coherent_kern_range)
/*
* coherent_user_range(start, end)
*
* Ensure coherency between the Icache and the Dcache in the
* region described by start. If you have non-snooping
* Harvard caches, you need to implement this function.
*
* - start - virtual start address
* - end - virtual end address
*/
SYM_TYPED_FUNC_START(v4_coherent_user_range)
mov r0, #0
ret lr
SYM_FUNC_END(v4_coherent_user_range)
/*
* flush_kern_dcache_area(void *addr, size_t size)
*
* Ensure no D cache aliasing occurs, either with itself or
* the I cache
*
* - addr - kernel address
* - size - region size
*/
SYM_TYPED_FUNC_START(v4_flush_kern_dcache_area)
#ifdef CONFIG_CFI_CLANG /* Fallthrough if !CFI */
b v4_dma_flush_range
#endif
SYM_FUNC_END(v4_flush_kern_dcache_area)
/*
* dma_flush_range(start, end)
*
* Clean and invalidate the specified virtual address range.
*
* - start - virtual start address
* - end - virtual end address
*/
SYM_TYPED_FUNC_START(v4_dma_flush_range)
#ifdef CONFIG_CPU_CP15
mov r0, #0
mcr p15, 0, r0, c7, c7, 0 @ flush ID cache
#endif
ret lr
SYM_FUNC_END(v4_dma_flush_range)
/*
* dma_unmap_area(start, size, dir)
* - start - kernel virtual start address
* - size - size of region
* - dir - DMA direction
*/
SYM_TYPED_FUNC_START(v4_dma_unmap_area)
teq r2, #DMA_TO_DEVICE
bne v4_dma_flush_range
ret lr
SYM_FUNC_END(v4_dma_unmap_area)
/*
* dma_map_area(start, size, dir)
* - start - kernel virtual start address
* - size - size of region
* - dir - DMA direction
*/
SYM_TYPED_FUNC_START(v4_dma_map_area)
ret lr
SYM_FUNC_END(v4_dma_map_area)