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[ARM] 4497/1: Only allow safe cache configurations on ARMv6 and later

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Currently, Linux doesn't generate correct page tables for ARMv6 and
later cores if the cache policy is different from the default one (it
may lead to strongly ordered or shared device mappings). This patch
disallows cache policies other than writeback and the
CPU_[ID]CACHE_DISABLE options only affect the CP15 system control
register rather than the page tables.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Catalin Marinas
2007-07-20 11:42:24 +01:00
committed by Russell King
parent 2eb8c82bc4
commit 11179d8ca2
2 changed files with 11 additions and 5 deletions
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14
arch/arm/mm/mmu.c
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@@ -114,6 +114,10 @@ static void __init early_cachepolicy(char **p)
}
if (i == ARRAY_SIZE(cache_policies))
printk(KERN_ERR "ERROR: unknown or unsupported cache policy\n");
if (cpu_architecture() >= CPU_ARCH_ARMv6) {
printk(KERN_WARNING "Only cachepolicy=writeback supported on ARMv6 and later\n");
cachepolicy = CPOLICY_WRITEBACK;
}
flush_cache_all();
set_cr(cr_alignment);
}
@@ -252,13 +256,15 @@ static void __init build_mem_type_table(void)
int cpu_arch = cpu_architecture();
int i;
if (cpu_arch < CPU_ARCH_ARMv6) {
#if defined(CONFIG_CPU_DCACHE_DISABLE)
if (cachepolicy > CPOLICY_BUFFERED)
cachepolicy = CPOLICY_BUFFERED;
if (cachepolicy > CPOLICY_BUFFERED)
cachepolicy = CPOLICY_BUFFERED;
#elif defined(CONFIG_CPU_DCACHE_WRITETHROUGH)
if (cachepolicy > CPOLICY_WRITETHROUGH)
cachepolicy = CPOLICY_WRITETHROUGH;
if (cachepolicy > CPOLICY_WRITETHROUGH)
cachepolicy = CPOLICY_WRITETHROUGH;
#endif
}
if (cpu_arch < CPU_ARCH_ARMv5) {
if (cachepolicy >= CPOLICY_WRITEALLOC)
cachepolicy = CPOLICY_WRITEBACK;