diff options
Diffstat (limited to 'arch/arm/cpu/mmu-early.c')
| -rw-r--r-- | arch/arm/cpu/mmu-early.c | 27 |
1 files changed, 24 insertions, 3 deletions
diff --git a/arch/arm/cpu/mmu-early.c b/arch/arm/cpu/mmu-early.c index d39a03ed95..2f5876fc46 100644 --- a/arch/arm/cpu/mmu-early.c +++ b/arch/arm/cpu/mmu-early.c @@ -5,17 +5,20 @@ #include <asm/memory.h> #include <asm/system.h> #include <asm/cache.h> +#include <asm-generic/sections.h> #include "mmu.h" static uint32_t *ttb; -static void map_cachable(unsigned long start, unsigned long size) +static inline void map_region(unsigned long start, unsigned long size, + uint64_t flags) + { start = ALIGN_DOWN(start, SZ_1M); size = ALIGN(size, SZ_1M); - create_sections(ttb, start, start + size - 1, PMD_SECT_DEF_CACHED); + create_sections(ttb, start, start + size - 1, flags); } void mmu_early_enable(unsigned long membase, unsigned long memsize, @@ -28,9 +31,27 @@ void mmu_early_enable(unsigned long membase, unsigned long memsize, set_ttbr(ttb); set_domain(DOMAIN_MANAGER); + /* + * This marks the whole address space as uncachable as well as + * unexecutable if possible + */ create_flat_mapping(ttb); - map_cachable(membase, memsize); + /* + * There can be SoCs that have a section shared between device memory + * and the on-chip RAM hosting the PBL. Thus mark this section + * uncachable, but executable. + * On such SoCs, executing from OCRAM could cause the instruction + * prefetcher to speculatively access that device memory, triggering + * potential errant behavior. + * + * If your SoC has such a memory layout, you should rewrite the code + * here to map the OCRAM page-wise. + */ + map_region((unsigned long)_stext, _etext - _stext, PMD_SECT_DEF_UNCACHED); + + /* maps main memory as cachable */ + map_region(membase, memsize, PMD_SECT_DEF_CACHED); __mmu_cache_on(); } |