/* * 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 <arch/chip.h> /* 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 ro-after-init, 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 "ro-after-init" be synonyms. We keep the attribute * separate in case we change our minds at a future date. */ #define __ro_after_init __read_mostly #endif /* _ASM_TILE_CACHE_H */ |