When we create a higher level page table we have to initialize it
with the settings from the previous lower level page table so that
we do not modify unrelated mappings. split_block() is taken from
U-Boot code and does this job.
Signed-off-by: Sascha Hauer <s.ha...@pengutronix.de>
---
arch/arm/cpu/mmu_64.c | 39 ++++++++++++++++++++++++++++++++++-----
1 file changed, 34 insertions(+), 5 deletions(-)
diff --git a/arch/arm/cpu/mmu_64.c b/arch/arm/cpu/mmu_64.c
index baa443f9e2..2934ad12cd 100644
--- a/arch/arm/cpu/mmu_64.c
+++ b/arch/arm/cpu/mmu_64.c
@@ -123,10 +123,8 @@ static uint64_t *get_level_table(uint64_t *pte)
{
uint64_t *table = (uint64_t *)(*pte & XLAT_ADDR_MASK);
- if (pte_type(pte) != PTE_TYPE_TABLE) {
- table = create_table();
- set_table(pte, table);
- }
+ if (pte_type(pte) != PTE_TYPE_TABLE)
+ BUG();
return table;
}
@@ -154,6 +152,36 @@ static __maybe_unused uint64_t *find_pte(uint64_t addr)
return pte;
}
+#define MAX_PTE_ENTRIES 512
+
+/* Splits a block PTE into table with subpages spanning the old block */
+static void split_block(uint64_t *pte, int level)
+{
+ uint64_t old_pte = *pte;
+ uint64_t *new_table;
+ uint64_t i = 0;
+ int levelshift;
+
+ if ((*pte & PTE_TYPE_MASK) == PTE_TYPE_TABLE)
+ return;
+
+ /* level describes the parent level, we need the child ones */
+ levelshift = level2shift(level + 1);
+
+ new_table = create_table();
+
+ for (i = 0; i < MAX_PTE_ENTRIES; i++) {
+ new_table[i] = old_pte | (i << levelshift);
+
+ /* Level 3 block PTEs have the table type */
+ if ((level + 1) == 3)
+ new_table[i] |= PTE_TYPE_TABLE;
+ }
+
+ /* Set the new table into effect */
+ set_table(pte, new_table);
+}
+
static void map_region(uint64_t virt, uint64_t phys, uint64_t size, uint64_t
attr)
{
uint64_t block_size;
@@ -191,7 +219,8 @@ static void map_region(uint64_t virt, uint64_t phys,
uint64_t size, uint64_t att
phys += block_size;
size -= block_size;
break;
-
+ } else {
+ split_block(pte, level);
}
table = get_level_table(pte);
--
2.16.1
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