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Diffstat (limited to 'arch/arm/mm/mmu.c')
-rw-r--r--arch/arm/mm/mmu.c43
1 files changed, 38 insertions, 5 deletions
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 4f56617a2392..b3fdb63783e3 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -989,6 +989,7 @@ phys_addr_t arm_lowmem_limit __initdata = 0;
void __init sanity_check_meminfo(void)
{
+ phys_addr_t memblock_limit = 0;
int i, j, highmem = 0;
phys_addr_t vmalloc_limit = __pa(vmalloc_min - 1) + 1;
@@ -1052,9 +1053,32 @@ void __init sanity_check_meminfo(void)
bank->size = size_limit;
}
#endif
- if (!bank->highmem && bank->start + bank->size > arm_lowmem_limit)
- arm_lowmem_limit = bank->start + bank->size;
+ if (!bank->highmem) {
+ phys_addr_t bank_end = bank->start + bank->size;
+ if (bank_end > arm_lowmem_limit)
+ arm_lowmem_limit = bank_end;
+
+ /*
+ * Find the first non-section-aligned page, and point
+ * memblock_limit at it. This relies on rounding the
+ * limit down to be section-aligned, which happens at
+ * the end of this function.
+ *
+ * With this algorithm, the start or end of almost any
+ * bank can be non-section-aligned. The only exception
+ * is that the start of the bank 0 must be section-
+ * aligned, since otherwise memory would need to be
+ * allocated when mapping the start of bank 0, which
+ * occurs before any free memory is mapped.
+ */
+ if (!memblock_limit) {
+ if (!IS_ALIGNED(bank->start, SECTION_SIZE))
+ memblock_limit = bank->start;
+ else if (!IS_ALIGNED(bank_end, SECTION_SIZE))
+ memblock_limit = bank_end;
+ }
+ }
j++;
}
#ifdef CONFIG_HIGHMEM
@@ -1079,7 +1103,18 @@ void __init sanity_check_meminfo(void)
#endif
meminfo.nr_banks = j;
high_memory = __va(arm_lowmem_limit - 1) + 1;
- memblock_set_current_limit(arm_lowmem_limit);
+
+ /*
+ * Round the memblock limit down to a section size. This
+ * helps to ensure that we will allocate memory from the
+ * last full section, which should be mapped.
+ */
+ if (memblock_limit)
+ memblock_limit = round_down(memblock_limit, SECTION_SIZE);
+ if (!memblock_limit)
+ memblock_limit = arm_lowmem_limit;
+
+ memblock_set_current_limit(memblock_limit);
}
static inline void prepare_page_table(void)
@@ -1276,8 +1311,6 @@ void __init paging_init(struct machine_desc *mdesc)
{
void *zero_page;
- memblock_set_current_limit(arm_lowmem_limit);
-
build_mem_type_table();
prepare_page_table();
map_lowmem();