diff options
| -rw-r--r-- | arch/arm/kernel/setup.c | 5 | ||||
| -rw-r--r-- | arch/arm/mm/mmu.c | 63 |
2 files changed, 51 insertions, 17 deletions
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c index df21f9f9894..f5120ca0867 100644 --- a/arch/arm/kernel/setup.c +++ b/arch/arm/kernel/setup.c @@ -72,6 +72,7 @@ static int __init fpe_setup(char *line) __setup("fpe=", fpe_setup); #endif +extern void init_default_cache_policy(unsigned long); extern void paging_init(const struct machine_desc *desc); extern void early_paging_init(const struct machine_desc *, struct proc_info_list *); @@ -603,7 +604,9 @@ static void __init setup_processor(void) #ifndef CONFIG_ARM_THUMB elf_hwcap &= ~(HWCAP_THUMB | HWCAP_IDIVT); #endif - +#ifdef CONFIG_MMU + init_default_cache_policy(list->__cpu_mm_mmu_flags); +#endif erratum_a15_798181_init(); feat_v6_fixup(); diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c index 9c8fec02c27..92df149c88a 100644 --- a/arch/arm/mm/mmu.c +++ b/arch/arm/mm/mmu.c @@ -118,27 +118,49 @@ static struct cachepolicy cache_policies[] __initdata = { #ifdef CONFIG_CPU_CP15 /* - * These are useful for identifying cache coherency - * problems by allowing the cache or the cache and - * writebuffer to be turned off. (Note: the write - * buffer should not be on and the cache off). + * Initialise the cache_policy variable with the initial state specified + * via the "pmd" value. This is used to ensure that on ARMv6 and later, + * the C code sets the page tables up with the same policy as the head + * assembly code, which avoids an illegal state where the TLBs can get + * confused. See comments in early_cachepolicy() for more information. */ -static int __init early_cachepolicy(char *p) +void __init init_default_cache_policy(unsigned long pmd) { - unsigned long cr = get_cr(); int i; + pmd &= PMD_SECT_TEX(1) | PMD_SECT_BUFFERABLE | PMD_SECT_CACHEABLE; + + for (i = 0; i < ARRAY_SIZE(cache_policies); i++) + if (cache_policies[i].pmd == pmd) { + cachepolicy = i; + break; + } + + if (i == ARRAY_SIZE(cache_policies)) + pr_err("ERROR: could not find cache policy\n"); +} + +/* + * These are useful for identifying cache coherency problems by allowing + * the cache or the cache and writebuffer to be turned off. (Note: the + * write buffer should not be on and the cache off). + */ +static int __init early_cachepolicy(char *p) +{ + int i, selected = -1; + for (i = 0; i < ARRAY_SIZE(cache_policies); i++) { int len = strlen(cache_policies[i].policy); if (memcmp(p, cache_policies[i].policy, len) == 0) { - cachepolicy = i; - cr = __clear_cr(cache_policies[i].cr_mask); + selected = i; break; } } - if (i == ARRAY_SIZE(cache_policies)) - printk(KERN_ERR "ERROR: unknown or unsupported cache policy\n"); + + if (selected == -1) + pr_err("ERROR: unknown or unsupported cache policy\n"); + /* * This restriction is partly to do with the way we boot; it is * unpredictable to have memory mapped using two different sets of @@ -146,12 +168,18 @@ static int __init early_cachepolicy(char *p) * change these attributes once the initial assembly has setup the * page tables. */ - if (cpu_architecture() >= CPU_ARCH_ARMv6) { - printk(KERN_WARNING "Only cachepolicy=writeback supported on ARMv6 and later\n"); - cachepolicy = CPOLICY_WRITEBACK; + if (cpu_architecture() >= CPU_ARCH_ARMv6 && selected != cachepolicy) { + pr_warn("Only cachepolicy=%s supported on ARMv6 and later\n", + cache_policies[cachepolicy].policy); + return 0; + } + + if (selected != cachepolicy) { + unsigned long cr = __clear_cr(cache_policies[selected].cr_mask); + cachepolicy = selected; + flush_cache_all(); + set_cr(cr); } - flush_cache_all(); - set_cr(cr); return 0; } early_param("cachepolicy", early_cachepolicy); @@ -385,8 +413,11 @@ static void __init build_mem_type_table(void) cachepolicy = CPOLICY_WRITEBACK; ecc_mask = 0; } - if (is_smp()) + + if (is_smp() && cachepolicy != CPOLICY_WRITEALLOC) { + pr_warn("Forcing write-allocate cache policy for SMP\n"); cachepolicy = CPOLICY_WRITEALLOC; + } /* * Strip out features not present on earlier architectures. |