diff options
Diffstat (limited to 'arch/x86/mm/init.c')
| -rw-r--r-- | arch/x86/mm/init.c | 194 |
1 files changed, 149 insertions, 45 deletions
diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index 59b7fc45327..f9713061811 100644 --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -53,12 +53,12 @@ __ref void *alloc_low_pages(unsigned int num) if ((pgt_buf_end + num) > pgt_buf_top || !can_use_brk_pgt) { unsigned long ret; if (min_pfn_mapped >= max_pfn_mapped) - panic("alloc_low_page: ran out of memory"); + panic("alloc_low_pages: ran out of memory"); ret = memblock_find_in_range(min_pfn_mapped << PAGE_SHIFT, max_pfn_mapped << PAGE_SHIFT, PAGE_SIZE * num , PAGE_SIZE); if (!ret) - panic("alloc_low_page: can not alloc memory"); + panic("alloc_low_pages: can not alloc memory"); memblock_reserve(ret, PAGE_SIZE * num); pfn = ret >> PAGE_SHIFT; } else { @@ -78,8 +78,8 @@ __ref void *alloc_low_pages(unsigned int num) return __va(pfn << PAGE_SHIFT); } -/* need 4 4k for initial PMD_SIZE, 4k for 0-ISA_END_ADDRESS */ -#define INIT_PGT_BUF_SIZE (5 * PAGE_SIZE) +/* need 3 4k for initial PMD_SIZE, 3 4k for 0-ISA_END_ADDRESS */ +#define INIT_PGT_BUF_SIZE (6 * PAGE_SIZE) RESERVE_BRK(early_pgt_alloc, INIT_PGT_BUF_SIZE); void __init early_alloc_pgt_buf(void) { @@ -277,6 +277,9 @@ static int __meminit split_mem_range(struct map_range *mr, int nr_range, end_pfn = limit_pfn; nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0); + if (!after_bootmem) + adjust_range_page_size_mask(mr, nr_range); + /* try to merge same page size and continuous */ for (i = 0; nr_range > 1 && i < nr_range - 1; i++) { unsigned long old_start; @@ -291,9 +294,6 @@ static int __meminit split_mem_range(struct map_range *mr, int nr_range, nr_range--; } - if (!after_bootmem) - adjust_range_page_size_mask(mr, nr_range); - for (i = 0; i < nr_range; i++) printk(KERN_DEBUG " [mem %#010lx-%#010lx] page %s\n", mr[i].start, mr[i].end - 1, @@ -359,7 +359,17 @@ unsigned long __init_refok init_memory_mapping(unsigned long start, } /* - * would have hole in the middle or ends, and only ram parts will be mapped. + * We need to iterate through the E820 memory map and create direct mappings + * for only E820_RAM and E820_KERN_RESERVED regions. We cannot simply + * create direct mappings for all pfns from [0 to max_low_pfn) and + * [4GB to max_pfn) because of possible memory holes in high addresses + * that cannot be marked as UC by fixed/variable range MTRRs. + * Depending on the alignment of E820 ranges, this may possibly result + * in using smaller size (i.e. 4K instead of 2M or 1G) page tables. + * + * init_mem_mapping() calls init_range_memory_mapping() with big range. + * That range would have hole in the middle or ends, and only ram parts + * will be mapped in init_range_memory_mapping(). */ static unsigned long __init init_range_memory_mapping( unsigned long r_start, @@ -389,29 +399,46 @@ static unsigned long __init init_range_memory_mapping( return mapped_ram_size; } -/* (PUD_SHIFT-PMD_SHIFT)/2 */ -#define STEP_SIZE_SHIFT 5 -void __init init_mem_mapping(void) +static unsigned long __init get_new_step_size(unsigned long step_size) { - unsigned long end, real_end, start, last_start; + /* + * Explain why we shift by 5 and why we don't have to worry about + * 'step_size << 5' overflowing: + * + * initial mapped size is PMD_SIZE (2M). + * We can not set step_size to be PUD_SIZE (1G) yet. + * In worse case, when we cross the 1G boundary, and + * PG_LEVEL_2M is not set, we will need 1+1+512 pages (2M + 8k) + * to map 1G range with PTE. Use 5 as shift for now. + * + * Don't need to worry about overflow, on 32bit, when step_size + * is 0, round_down() returns 0 for start, and that turns it + * into 0x100000000ULL. + */ + return step_size << 5; +} + +/** + * memory_map_top_down - Map [map_start, map_end) top down + * @map_start: start address of the target memory range + * @map_end: end address of the target memory range + * + * This function will setup direct mapping for memory range + * [map_start, map_end) in top-down. That said, the page tables + * will be allocated at the end of the memory, and we map the + * memory in top-down. + */ +static void __init memory_map_top_down(unsigned long map_start, + unsigned long map_end) +{ + unsigned long real_end, start, last_start; unsigned long step_size; unsigned long addr; unsigned long mapped_ram_size = 0; unsigned long new_mapped_ram_size; - probe_page_size_mask(); - -#ifdef CONFIG_X86_64 - end = max_pfn << PAGE_SHIFT; -#else - end = max_low_pfn << PAGE_SHIFT; -#endif - - /* the ISA range is always mapped regardless of memory holes */ - init_memory_mapping(0, ISA_END_ADDRESS); - /* xen has big range in reserved near end of ram, skip it at first.*/ - addr = memblock_find_in_range(ISA_END_ADDRESS, end, PMD_SIZE, PMD_SIZE); + addr = memblock_find_in_range(map_start, map_end, PMD_SIZE, PMD_SIZE); real_end = addr + PMD_SIZE; /* step_size need to be small so pgt_buf from BRK could cover it */ @@ -419,25 +446,113 @@ void __init init_mem_mapping(void) max_pfn_mapped = 0; /* will get exact value next */ min_pfn_mapped = real_end >> PAGE_SHIFT; last_start = start = real_end; - while (last_start > ISA_END_ADDRESS) { + + /* + * We start from the top (end of memory) and go to the bottom. + * The memblock_find_in_range() gets us a block of RAM from the + * end of RAM in [min_pfn_mapped, max_pfn_mapped) used as new pages + * for page table. + */ + while (last_start > map_start) { if (last_start > step_size) { start = round_down(last_start - 1, step_size); - if (start < ISA_END_ADDRESS) - start = ISA_END_ADDRESS; + if (start < map_start) + start = map_start; } else - start = ISA_END_ADDRESS; + start = map_start; new_mapped_ram_size = init_range_memory_mapping(start, last_start); last_start = start; min_pfn_mapped = last_start >> PAGE_SHIFT; /* only increase step_size after big range get mapped */ if (new_mapped_ram_size > mapped_ram_size) - step_size <<= STEP_SIZE_SHIFT; + step_size = get_new_step_size(step_size); + mapped_ram_size += new_mapped_ram_size; + } + + if (real_end < map_end) + init_range_memory_mapping(real_end, map_end); +} + +/** + * memory_map_bottom_up - Map [map_start, map_end) bottom up + * @map_start: start address of the target memory range + * @map_end: end address of the target memory range + * + * This function will setup direct mapping for memory range + * [map_start, map_end) in bottom-up. Since we have limited the + * bottom-up allocation above the kernel, the page tables will + * be allocated just above the kernel and we map the memory + * in [map_start, map_end) in bottom-up. + */ +static void __init memory_map_bottom_up(unsigned long map_start, + unsigned long map_end) +{ + unsigned long next, new_mapped_ram_size, start; + unsigned long mapped_ram_size = 0; + /* step_size need to be small so pgt_buf from BRK could cover it */ + unsigned long step_size = PMD_SIZE; + + start = map_start; + min_pfn_mapped = start >> PAGE_SHIFT; + + /* + * We start from the bottom (@map_start) and go to the top (@map_end). + * The memblock_find_in_range() gets us a block of RAM from the + * end of RAM in [min_pfn_mapped, max_pfn_mapped) used as new pages + * for page table. + */ + while (start < map_end) { + if (map_end - start > step_size) { + next = round_up(start + 1, step_size); + if (next > map_end) + next = map_end; + } else + next = map_end; + + new_mapped_ram_size = init_range_memory_mapping(start, next); + start = next; + + if (new_mapped_ram_size > mapped_ram_size) + step_size = get_new_step_size(step_size); mapped_ram_size += new_mapped_ram_size; } +} - if (real_end < end) - init_range_memory_mapping(real_end, end); +void __init init_mem_mapping(void) +{ + unsigned long end; + + probe_page_size_mask(); + +#ifdef CONFIG_X86_64 + end = max_pfn << PAGE_SHIFT; +#else + end = max_low_pfn << PAGE_SHIFT; +#endif + + /* the ISA range is always mapped regardless of memory holes */ + init_memory_mapping(0, ISA_END_ADDRESS); + + /* + * If the allocation is in bottom-up direction, we setup direct mapping + * in bottom-up, otherwise we setup direct mapping in top-down. + */ + if (memblock_bottom_up()) { + unsigned long kernel_end = __pa_symbol(_end); + + /* + * we need two separate calls here. This is because we want to + * allocate page tables above the kernel. So we first map + * [kernel_end, end) to make memory above the kernel be mapped + * as soon as possible. And then use page tables allocated above + * the kernel to map [ISA_END_ADDRESS, kernel_end). + */ + memory_map_bottom_up(kernel_end, end); + memory_map_bottom_up(ISA_END_ADDRESS, kernel_end); + } else { + memory_map_top_down(ISA_END_ADDRESS, end); + } #ifdef CONFIG_X86_64 if (max_pfn > max_low_pfn) { @@ -477,7 +592,6 @@ int devmem_is_allowed(unsigned long pagenr) void free_init_pages(char *what, unsigned long begin, unsigned long end) { - unsigned long addr; unsigned long begin_aligned, end_aligned; /* Make sure boundaries are page aligned */ @@ -492,8 +606,6 @@ void free_init_pages(char *what, unsigned long begin, unsigned long end) if (begin >= end) return; - addr = begin; - /* * If debugging page accesses then do not free this memory but * mark them not present - any buggy init-section access will @@ -512,21 +624,13 @@ void free_init_pages(char *what, unsigned long begin, unsigned long end) set_memory_nx(begin, (end - begin) >> PAGE_SHIFT); set_memory_rw(begin, (end - begin) >> PAGE_SHIFT); - printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10); - - for (; addr < end; addr += PAGE_SIZE) { - ClearPageReserved(virt_to_page(addr)); - init_page_count(virt_to_page(addr)); - memset((void *)addr, POISON_FREE_INITMEM, PAGE_SIZE); - free_page(addr); - totalram_pages++; - } + free_reserved_area((void *)begin, (void *)end, POISON_FREE_INITMEM, what); #endif } void free_initmem(void) { - free_init_pages("unused kernel memory", + free_init_pages("unused kernel", (unsigned long)(&__init_begin), (unsigned long)(&__init_end)); } @@ -552,7 +656,7 @@ void __init free_initrd_mem(unsigned long start, unsigned long end) * - relocate_initrd() * So here We can do PAGE_ALIGN() safely to get partial page to be freed */ - free_init_pages("initrd memory", start, PAGE_ALIGN(end)); + free_init_pages("initrd", start, PAGE_ALIGN(end)); } #endif |