diff options
Diffstat (limited to 'arch/arm')
| -rw-r--r-- | arch/arm/mm/mmu.c | 144 |
1 files changed, 111 insertions, 33 deletions
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c index ebdc13148065..7583bda5ea7d 100644 --- a/arch/arm/mm/mmu.c +++ b/arch/arm/mm/mmu.c @@ -1459,8 +1459,6 @@ static void __init kmap_init(void) static void __init map_lowmem(void) { - phys_addr_t kernel_x_start = round_down(__pa(KERNEL_START), SECTION_SIZE); - phys_addr_t kernel_x_end = round_up(__pa(__init_end), SECTION_SIZE); phys_addr_t start, end; u64 i; @@ -1468,55 +1466,126 @@ static void __init map_lowmem(void) for_each_mem_range(i, &start, &end) { struct map_desc map; + pr_debug("map lowmem start: 0x%08llx, end: 0x%08llx\n", + (long long)start, (long long)end); if (end > arm_lowmem_limit) end = arm_lowmem_limit; if (start >= end) break; - if (end < kernel_x_start) { - map.pfn = __phys_to_pfn(start); - map.virtual = __phys_to_virt(start); - map.length = end - start; - map.type = MT_MEMORY_RWX; + /* + * If our kernel image is in the VMALLOC area we need to remove + * the kernel physical memory from lowmem since the kernel will + * be mapped separately. + * + * The kernel will typically be at the very start of lowmem, + * but any placement relative to memory ranges is possible. + * + * If the memblock contains the kernel, we have to chisel out + * the kernel memory from it and map each part separately. We + * get 6 different theoretical cases: + * + * +--------+ +--------+ + * +-- start --+ +--------+ | Kernel | | Kernel | + * | | | Kernel | | case 2 | | case 5 | + * | | | case 1 | +--------+ | | +--------+ + * | Memory | +--------+ | | | Kernel | + * | range | +--------+ | | | case 6 | + * | | | Kernel | +--------+ | | +--------+ + * | | | case 3 | | Kernel | | | + * +-- end ----+ +--------+ | case 4 | | | + * +--------+ +--------+ + */ - create_mapping(&map); - } else if (start >= kernel_x_end) { - map.pfn = __phys_to_pfn(start); - map.virtual = __phys_to_virt(start); - map.length = end - start; - map.type = MT_MEMORY_RW; + /* Case 5: kernel covers range, don't map anything, should be rare */ + if ((start > kernel_sec_start) && (end < kernel_sec_end)) + break; - create_mapping(&map); - } else { - /* This better cover the entire kernel */ - if (start < kernel_x_start) { + /* Cases where the kernel is starting inside the range */ + if ((kernel_sec_start >= start) && (kernel_sec_start <= end)) { + /* Case 6: kernel is embedded in the range, we need two mappings */ + if ((start < kernel_sec_start) && (end > kernel_sec_end)) { + /* Map memory below the kernel */ map.pfn = __phys_to_pfn(start); map.virtual = __phys_to_virt(start); - map.length = kernel_x_start - start; + map.length = kernel_sec_start - start; map.type = MT_MEMORY_RW; - create_mapping(&map); - } - - map.pfn = __phys_to_pfn(kernel_x_start); - map.virtual = __phys_to_virt(kernel_x_start); - map.length = kernel_x_end - kernel_x_start; - map.type = MT_MEMORY_RWX; - - create_mapping(&map); - - if (kernel_x_end < end) { - map.pfn = __phys_to_pfn(kernel_x_end); - map.virtual = __phys_to_virt(kernel_x_end); - map.length = end - kernel_x_end; + /* Map memory above the kernel */ + map.pfn = __phys_to_pfn(kernel_sec_end); + map.virtual = __phys_to_virt(kernel_sec_end); + map.length = end - kernel_sec_end; map.type = MT_MEMORY_RW; - create_mapping(&map); + break; } + /* Case 1: kernel and range start at the same address, should be common */ + if (kernel_sec_start == start) + start = kernel_sec_end; + /* Case 3: kernel and range end at the same address, should be rare */ + if (kernel_sec_end == end) + end = kernel_sec_start; + } else if ((kernel_sec_start < start) && (kernel_sec_end > start) && (kernel_sec_end < end)) { + /* Case 2: kernel ends inside range, starts below it */ + start = kernel_sec_end; + } else if ((kernel_sec_start > start) && (kernel_sec_start < end) && (kernel_sec_end > end)) { + /* Case 4: kernel starts inside range, ends above it */ + end = kernel_sec_start; } + map.pfn = __phys_to_pfn(start); + map.virtual = __phys_to_virt(start); + map.length = end - start; + map.type = MT_MEMORY_RW; + create_mapping(&map); } } +static void __init map_kernel(void) +{ + /* + * We use the well known kernel section start and end and split the area in the + * middle like this: + * . . + * | RW memory | + * +----------------+ kernel_x_start + * | Executable | + * | kernel memory | + * +----------------+ kernel_x_end / kernel_nx_start + * | Non-executable | + * | kernel memory | + * +----------------+ kernel_nx_end + * | RW memory | + * . . + * + * Notice that we are dealing with section sized mappings here so all of this + * will be bumped to the closest section boundary. This means that some of the + * non-executable part of the kernel memory is actually mapped as executable. + * This will only persist until we turn on proper memory management later on + * and we remap the whole kernel with page granularity. + */ + phys_addr_t kernel_x_start = kernel_sec_start; + phys_addr_t kernel_x_end = round_up(__pa(__init_end), SECTION_SIZE); + phys_addr_t kernel_nx_start = kernel_x_end; + phys_addr_t kernel_nx_end = kernel_sec_end; + struct map_desc map; + + map.pfn = __phys_to_pfn(kernel_x_start); + map.virtual = __phys_to_virt(kernel_x_start); + map.length = kernel_x_end - kernel_x_start; + map.type = MT_MEMORY_RWX; + create_mapping(&map); + + /* If the nx part is small it may end up covered by the tail of the RWX section */ + if (kernel_x_end == kernel_nx_end) + return; + + map.pfn = __phys_to_pfn(kernel_nx_start); + map.virtual = __phys_to_virt(kernel_nx_start); + map.length = kernel_nx_end - kernel_nx_start; + map.type = MT_MEMORY_RW; + create_mapping(&map); +} + #ifdef CONFIG_ARM_PV_FIXUP typedef void pgtables_remap(long long offset, unsigned long pgd); pgtables_remap lpae_pgtables_remap_asm; @@ -1647,9 +1716,18 @@ void __init paging_init(const struct machine_desc *mdesc) { void *zero_page; + pr_debug("physical kernel sections: 0x%08x-0x%08x\n", + kernel_sec_start, kernel_sec_end); + prepare_page_table(); map_lowmem(); memblock_set_current_limit(arm_lowmem_limit); + pr_debug("lowmem limit is %08llx\n", (long long)arm_lowmem_limit); + /* + * After this point early_alloc(), i.e. the memblock allocator, can + * be used + */ + map_kernel(); dma_contiguous_remap(); early_fixmap_shutdown(); devicemaps_init(mdesc); |