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aarch64: mmu: invert the MT_OVERWRITE flag

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The MT_OVERWRITE case is much more common. Redefine that flag as
MT_NO_OVERWRITE instead for those fewer cases where it is needed.

One such case is platform provided mappings. Apply them after the
common kernel mappings and use the MT_NO_OVERWRITE on them.

Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
This commit is contained in:
Nicolas Pitre 2021-02-14 16:08:21 -05:00 committed by Anas Nashif
parent 56c77118d3
commit cb49e4b789
2 changed files with 19 additions and 14 deletions
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29
arch/arm/core/aarch64/mmu/arm_mmu.c
View file

@ -316,7 +316,7 @@ static int add_map(struct arm_mmu_ptables *ptables, const char *name,
uintptr_t phys, uintptr_t virt, size_t size, uint32_t attrs)
{
uint64_t desc = get_region_desc(attrs);
bool may_overwrite = (attrs & MT_OVERWRITE);
bool may_overwrite = !(attrs & MT_NO_OVERWRITE);
MMU_DEBUG("mmap [%s]: virt %lx phys %lx size %lx attr %llx\n",
name, virt, phys, size, desc);
@ -361,10 +361,11 @@ static const struct arm_mmu_region mmu_zephyr_regions[] = {
};
static inline void add_arm_mmu_region(struct arm_mmu_ptables *ptables,
const struct arm_mmu_region *region)
const struct arm_mmu_region *region,
uint32_t extra_flags)
{
add_map(ptables, region->name, region->base_pa, region->base_va,
region->size, region->attrs);
region->size, region->attrs | extra_flags);
}
static void setup_page_tables(struct arm_mmu_ptables *ptables)
@ -388,19 +389,23 @@ static void setup_page_tables(struct arm_mmu_ptables *ptables)
__ASSERT(max_pa <= (1ULL << CONFIG_ARM64_PA_BITS),
"Maximum PA not supported\n");
/* create translation tables for user provided platform regions */
for (index = 0; index < mmu_config.num_regions; index++) {
region = &mmu_config.mmu_regions[index];
if (region->size || region->attrs)
add_arm_mmu_region(ptables, region);
}
/* setup translation table for zephyr execution regions */
for (index = 0; index < ARRAY_SIZE(mmu_zephyr_regions); index++) {
region = &mmu_zephyr_regions[index];
if (region->size || region->attrs)
add_arm_mmu_region(ptables, region);
add_arm_mmu_region(ptables, region, 0);
}
/*
* Create translation tables for user provided platform regions.
* Those must not conflict with our default mapping.
*/
for (index = 0; index < mmu_config.num_regions; index++) {
region = &mmu_config.mmu_regions[index];
if (region->size || region->attrs)
add_arm_mmu_region(ptables, region, MT_NO_OVERWRITE);
}
}
/* Translation table control register settings */
@ -515,7 +520,7 @@ SYS_INIT(arm_mmu_init, PRE_KERNEL_1,
static int __arch_mem_map(void *virt, uintptr_t phys, size_t size, uint32_t flags)
{
struct arm_mmu_ptables *ptables;
uint32_t entry_flags = MT_SECURE | MT_P_RX_U_NA | MT_OVERWRITE;
uint32_t entry_flags = MT_SECURE | MT_P_RX_U_NA;
/* Always map in the kernel page tables */
ptables = &kernel_ptables;

4
include/arch/arm/aarch64/arm_mmu.h
View file

@ -46,7 +46,7 @@
#define MT_P_EXECUTE_SHIFT 5U
#define MT_U_EXECUTE_SHIFT 6U
#define MT_RW_AP_SHIFT 7U
#define MT_OVERWRITE_SHIFT 8U
#define MT_NO_OVERWRITE_SHIFT 8U
#define MT_RO (0U << MT_PERM_SHIFT)
#define MT_RW (1U << MT_PERM_SHIFT)
@ -63,7 +63,7 @@
#define MT_U_EXECUTE (0U << MT_U_EXECUTE_SHIFT)
#define MT_U_EXECUTE_NEVER (1U << MT_U_EXECUTE_SHIFT)
#define MT_OVERWRITE (1U << MT_OVERWRITE_SHIFT)
#define MT_NO_OVERWRITE (1U << MT_NO_OVERWRITE_SHIFT)
#define MT_P_RW_U_RW (MT_RW | MT_RW_AP_ELx | MT_P_EXECUTE_NEVER | MT_U_EXECUTE_NEVER)
#define MT_P_RW_U_NA (MT_RW | MT_RW_AP_EL_HIGHER | MT_P_EXECUTE_NEVER | MT_U_EXECUTE_NEVER)