diff options
Diffstat (limited to 'arch/arm64/mm/init.c')
| -rw-r--r-- | arch/arm64/mm/init.c | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c index d31c3a9290c5..4fcb88a445ef 100644 --- a/arch/arm64/mm/init.c +++ b/arch/arm64/mm/init.c @@ -73,6 +73,33 @@ phys_addr_t __ro_after_init arm64_dma_phys_limit; #define DEFAULT_CRASH_KERNEL_LOW_SIZE (128UL << 20) +/* + * To make optimal use of block mappings when laying out the linear + * mapping, round down the base of physical memory to a size that can + * be mapped efficiently, i.e., either PUD_SIZE (4k granule) or PMD_SIZE + * (64k granule), or a multiple that can be mapped using contiguous bits + * in the page tables: 32 * PMD_SIZE (16k granule) + */ +#if defined(CONFIG_ARM64_4K_PAGES) +#define ARM64_MEMSTART_SHIFT PUD_SHIFT +#elif defined(CONFIG_ARM64_16K_PAGES) +#define ARM64_MEMSTART_SHIFT CONT_PMD_SHIFT +#else +#define ARM64_MEMSTART_SHIFT PMD_SHIFT +#endif + +/* + * sparsemem vmemmap imposes an additional requirement on the alignment of + * memstart_addr, due to the fact that the base of the vmemmap region + * has a direct correspondence, and needs to appear sufficiently aligned + * in the virtual address space. + */ +#if ARM64_MEMSTART_SHIFT < SECTION_SIZE_BITS +#define ARM64_MEMSTART_ALIGN (1UL << SECTION_SIZE_BITS) +#else +#define ARM64_MEMSTART_ALIGN (1UL << ARM64_MEMSTART_SHIFT) +#endif + static int __init reserve_crashkernel_low(unsigned long long low_size) { unsigned long long low_base; |