From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Wed, 5 Aug 2015 17:04:01 -0300 Subject: Initial import --- arch/tile/include/asm/cache.h | 64 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 64 insertions(+) create mode 100644 arch/tile/include/asm/cache.h (limited to 'arch/tile/include/asm/cache.h') diff --git a/arch/tile/include/asm/cache.h b/arch/tile/include/asm/cache.h new file mode 100644 index 000000000..6160761d5 --- /dev/null +++ b/arch/tile/include/asm/cache.h @@ -0,0 +1,64 @@ +/* + * Copyright 2010 Tilera Corporation. All Rights Reserved. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation, version 2. + * + * 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, GOOD TITLE or + * NON INFRINGEMENT. See the GNU General Public License for + * more details. + */ + +#ifndef _ASM_TILE_CACHE_H +#define _ASM_TILE_CACHE_H + +#include + +/* bytes per L1 data cache line */ +#define L1_CACHE_SHIFT CHIP_L1D_LOG_LINE_SIZE() +#define L1_CACHE_BYTES (1 << L1_CACHE_SHIFT) + +/* bytes per L2 cache line */ +#define L2_CACHE_SHIFT CHIP_L2_LOG_LINE_SIZE() +#define L2_CACHE_BYTES (1 << L2_CACHE_SHIFT) +#define L2_CACHE_ALIGN(x) (((x)+(L2_CACHE_BYTES-1)) & -L2_CACHE_BYTES) + +/* + * TILEPro I/O is not always coherent (networking typically uses coherent + * I/O, but PCI traffic does not) and setting ARCH_DMA_MINALIGN to the + * L2 cacheline size helps ensure that kernel heap allocations are aligned. + * TILE-Gx I/O is always coherent when used on hash-for-home pages. + * + * However, it's possible at runtime to request not to use hash-for-home + * for the kernel heap, in which case the kernel will use flush-and-inval + * to manage coherence. As a result, we use L2_CACHE_BYTES for the + * DMA minimum alignment to avoid false sharing in the kernel heap. + */ +#define ARCH_DMA_MINALIGN L2_CACHE_BYTES + +/* use the cache line size for the L2, which is where it counts */ +#define SMP_CACHE_BYTES_SHIFT L2_CACHE_SHIFT +#define SMP_CACHE_BYTES L2_CACHE_BYTES +#define INTERNODE_CACHE_SHIFT L2_CACHE_SHIFT +#define INTERNODE_CACHE_BYTES L2_CACHE_BYTES + +/* Group together read-mostly things to avoid cache false sharing */ +#define __read_mostly __attribute__((__section__(".data..read_mostly"))) + +/* + * Originally we used small TLB pages for kernel data and grouped some + * things together as "write once", enforcing the property at the end + * of initialization by making those pages read-only and non-coherent. + * This allowed better cache utilization since cache inclusion did not + * need to be maintained. However, to do this requires an extra TLB + * entry, which on balance is more of a performance hit than the + * non-coherence is a performance gain, so we now just make "read + * mostly" and "write once" be synonyms. We keep the attribute + * separate in case we change our minds at a future date. + */ +#define __write_once __read_mostly + +#endif /* _ASM_TILE_CACHE_H */ -- cgit v1.2.3-54-g00ecf