From 57155c6523074dd937b8feafcfaa98c82218faa6 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Tue, 22 Mar 2016 22:02:23 +0000 Subject: [PATCH] sh: disable aliased page logic on NOMMU models SH3/4 (with MMU) have a virtually indexed cache, requiring explicit work to avoid consistency problems arising from having the same physical address range cached in multiple cache lines. This is unneeded for the NOMMU case, and some of the resulting code paths (kmap_coherent) don't work. SH2 only avoided this problem by having a 4-way associative cache with way size equal to the page size (4k), yielding no cache index bits outside of the page offset and thus no aliases. Signed-off-by: Rich Felker --- arch/sh/kernel/cpu/init.c | 4 ++++ arch/sh/mm/cache.c | 4 ++++ 2 files changed, 8 insertions(+) diff --git a/arch/sh/kernel/cpu/init.c b/arch/sh/kernel/cpu/init.c index 0d7360d549c1..bfd9e2798008 100644 --- a/arch/sh/kernel/cpu/init.c +++ b/arch/sh/kernel/cpu/init.c @@ -323,9 +323,13 @@ asmlinkage void cpu_init(void) cache_init(); if (raw_smp_processor_id() == 0) { +#ifdef CONFIG_MMU shm_align_mask = max_t(unsigned long, current_cpu_data.dcache.way_size - 1, PAGE_SIZE - 1); +#else + shm_align_mask = PAGE_SIZE - 1; +#endif /* Boot CPU sets the cache shape */ detect_cache_shape(); diff --git a/arch/sh/mm/cache.c b/arch/sh/mm/cache.c index e58cfbf45150..776d664a40c5 100644 --- a/arch/sh/mm/cache.c +++ b/arch/sh/mm/cache.c @@ -244,7 +244,11 @@ void flush_cache_sigtramp(unsigned long address) static void compute_alias(struct cache_info *c) { +#ifdef CONFIG_MMU c->alias_mask = ((c->sets - 1) << c->entry_shift) & ~(PAGE_SIZE - 1); +#else + c->alias_mask = 0; +#endif c->n_aliases = c->alias_mask ? (c->alias_mask >> PAGE_SHIFT) + 1 : 0; } -- 2.20.1