- 根目录:
- arch
- x86
- mm
- init.c
#include <linux/gfp.h>
#include <linux/initrd.h>
#include <linux/ioport.h>
#include <linux/swap.h>
#include <linux/memblock.h>
#include <linux/bootmem.h> /* for max_low_pfn */
#include <asm/cacheflush.h>
#include <asm/e820.h>
#include <asm/init.h>
#include <asm/page.h>
#include <asm/page_types.h>
#include <asm/sections.h>
#include <asm/setup.h>
#include <asm/tlbflush.h>
#include <asm/tlb.h>
#include <asm/proto.h>
#include <asm/dma.h> /* for MAX_DMA_PFN */
#include <asm/microcode.h>
/*
* We need to define the tracepoints somewhere, and tlb.c
* is only compied when SMP=y.
*/
#define CREATE_TRACE_POINTS
#include <trace/events/tlb.h>
#include "mm_internal.h"
static unsigned long __initdata pgt_buf_start;
static unsigned long __initdata pgt_buf_end;
static unsigned long __initdata pgt_buf_top;
static unsigned long min_pfn_mapped;
static bool __initdata can_use_brk_pgt = true;
/*
* Pages returned are already directly mapped.
*
* Changing that is likely to break Xen, see commit:
*
* 279b706 x86,xen: introduce x86_init.mapping.pagetable_reserve
*
* for detailed information.
*/
__ref void *alloc_low_pages(unsigned int num)
{
unsigned long pfn;
int i;
if (after_bootmem) {
unsigned int order;
order = get_order((unsigned long)num << PAGE_SHIFT);
return (void *)__get_free_pages(GFP_ATOMIC | __GFP_NOTRACK |
__GFP_ZERO, order);
}
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_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_pages: can not alloc memory");
memblock_reserve(ret, PAGE_SIZE * num);
pfn = ret >> PAGE_SHIFT;
} else {
pfn = pgt_buf_end;
pgt_buf_end += num;
printk(KERN_DEBUG "BRK [%#010lx, %#010lx] PGTABLE\n",
pfn << PAGE_SHIFT, (pgt_buf_end << PAGE_SHIFT) - 1);
}
for (i = 0; i < num; i++) {
void *adr;
adr = __va((pfn + i) << PAGE_SHIFT);
clear_page(adr);
}
return __va(pfn << PAGE_SHIFT);
}
/* 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)
{
unsigned long tables = INIT_PGT_BUF_SIZE;
phys_addr_t base;
base = __pa(extend_brk(tables, PAGE_SIZE));
pgt_buf_start = base >> PAGE_SHIFT;
pgt_buf_end = pgt_buf_start;
pgt_buf_top = pgt_buf_start + (tables >> PAGE_SHIFT);
}
int after_bootmem;
int direct_gbpages
#ifdef CONFIG_DIRECT_GBPAGES
= 1
#endif
;
static void __init init_gbpages(void)
{
#ifdef CONFIG_X86_64
if (direct_gbpages && cpu_has_gbpages)
printk(KERN_INFO "Using GB pages for direct mapping\n");
else
direct_gbpages = 0;
#endif
}
struct map_range {
unsigned long start;
unsigned long end;
unsigned page_size_mask;
};
static int page_size_mask;
static void __init probe_page_size_mask(void)
{
init_gbpages();
#if !defined(CONFIG_DEBUG_PAGEALLOC) && !defined(CONFIG_KMEMCHECK)
/*
* For CONFIG_DEBUG_PAGEALLOC, identity mapping will use small pages.
* This will simplify cpa(), which otherwise needs to support splitting
* large pages into small in interrupt context, etc.
*/
if (direct_gbpages)
page_size_mask |= 1 << PG_LEVEL_1G;
if (cpu_has_pse)
page_size_mask |= 1 << PG_LEVEL_2M;
#endif
/* Enable PSE if available */
if (cpu_has_pse)
set_in_cr4(X86_CR4_PSE);
/* Enable PGE if available */
if (cpu_has_pge) {
set_in_cr4(X86_CR4_PGE);
__supported_pte_mask |= _PAGE_GLOBAL;
}
}
#ifdef CONFIG_X86_32
#define NR_RANGE_MR 3
#else /* CONFIG_X86_64 */
#define NR_RANGE_MR 5
#endif
static int __meminit save_mr(struct map_range *mr, int nr_range,
unsigned long start_pfn, unsigned long end_pfn,
unsigned long page_size_mask)
{
if (start_pfn < end_pfn) {
if (nr_range >= NR_RANGE_MR)
panic("run out of range for init_memory_mapping\n");
mr[nr_range].start = start_pfn<<PAGE_SHIFT;
mr[nr_range].end = end_pfn<<PAGE_SHIFT;
mr[nr_range].page_size_mask = page_size_mask;
nr_range++;
}
return nr_range;
}
/*
* adjust the page_size_mask for small range to go with
* big page size instead small one if nearby are ram too.
*/
static void __init_refok adjust_range_page_size_mask(struct map_range *mr,
int nr_range)
{
int i;
for (i = 0; i < nr_range; i++) {
if ((page_size_mask & (1<<PG_LEVEL_2M)) &&
!(mr[i].page_size_mask & (1<<PG_LEVEL_2M))) {
unsigned long start = round_down(mr[i].start, PMD_SIZE);
unsigned long end = round_up(mr[i].end, PMD_SIZE);
#ifdef CONFIG_X86_32
if ((end >> PAGE_SHIFT) > max_low_pfn)
continue;
#endif
if (memblock_is_region_memory(start, end - start))
mr[i].page_size_mask |= 1<<PG_LEVEL_2M;
}
if ((page_size_mask & (1<<PG_LEVEL_1G)) &&
!(mr[i].page_size_mask & (1<<PG_LEVEL_1G))) {
unsigned long start = round_down(mr[i].start, PUD_SIZE);
unsigned long end = round_up(mr[i].end, PUD_SIZE);
if (memblock_is_region_memory(start, end - start))
mr[i].page_size_mask |= 1<<PG_LEVEL_1G;
}
}
}
static int __meminit split_mem_range(struct map_range *mr, int nr_range,
unsigned long start,
unsigned long end)
{
unsigned long start_pfn, end_pfn, limit_pfn;
unsigned long pfn;
int i;
limit_pfn = PFN_DOWN(end);
/* head if not big page alignment ? */
pfn = start_pfn = PFN_DOWN(start);
#ifdef CONFIG_X86_32
/*
* Don't use a large page for the first 2/4MB of memory
* because there are often fixed size MTRRs in there
* and overlapping MTRRs into large pages can cause
* slowdowns.
*/
if (pfn == 0)
end_pfn = PFN_DOWN(PMD_SIZE);
else
end_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE));
#else /* CONFIG_X86_64 */
end_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE));
#endif
if (end_pfn > limit_pfn)
end_pfn = limit_pfn;
if (start_pfn < end_pfn) {
nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
pfn = end_pfn;
}
/* big page (2M) range */
start_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE));
#ifdef CONFIG_X86_32
end_pfn = round_down(limit_pfn, PFN_DOWN(PMD_SIZE));
#else /* CONFIG_X86_64 */
end_pfn = round_up(pfn, PFN_DOWN(PUD_SIZE));
if (end_pfn > round_down(limit_pfn, PFN_DOWN(PMD_SIZE)))
end_pfn = round_down(limit_pfn, PFN_DOWN(PMD_SIZE));
#endif
if (start_pfn < end_pfn) {
nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
page_size_mask & (1<<PG_LEVEL_2M));
pfn = end_pfn;
}
#ifdef CONFIG_X86_64
/* big page (1G) range */
start_pfn = round_up(pfn, PFN_DOWN(PUD_SIZE));
end_pfn = round_down(limit_pfn, PFN_DOWN(PUD_SIZE));
if (start_pfn < end_pfn) {
nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
page_size_mask &
((1<<PG_LEVEL_2M)|(1<<PG_LEVEL_1G)));
pfn = end_pfn;
}
/* tail is not big page (1G) alignment */
start_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE));
end_pfn = round_down(limit_pfn, PFN_DOWN(PMD_SIZE));
if (start_pfn < end_pfn) {
nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
page_size_mask & (1<<PG_LEVEL_2M));
pfn = end_pfn;
}
#endif
/* tail is not big page (2M) alignment */
start_pfn = pfn;
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;
if (mr[i].end != mr[i+1].start ||
mr[i].page_size_mask != mr[i+1].page_size_mask)
continue;
/* move it */
old_start = mr[i].start;
memmove(&mr[i], &mr[i+1],
(nr_range - 1 - i) * sizeof(struct map_range));
mr[i--].start = old_start;
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,
(mr[i].page_size_mask & (1<<PG_LEVEL_1G))?"1G":(
(mr[i].page_size_mask & (1<<PG_LEVEL_2M))?"2M":"4k"));
return nr_range;
}
struct range pfn_mapped[E820_X_MAX];
int nr_pfn_mapped;
static void add_pfn_range_mapped(unsigned long start_pfn, unsigned long end_pfn)
{
nr_pfn_mapped = add_range_with_merge(pfn_mapped, E820_X_MAX,
nr_pfn_mapped, start_pfn, end_pfn);
nr_pfn_mapped = clean_sort_range(pfn_mapped, E820_X_MAX);
max_pfn_mapped = max(max_pfn_mapped, end_pfn);
if (start_pfn < (1UL<<(32-PAGE_SHIFT)))
max_low_pfn_mapped = max(max_low_pfn_mapped,
min(end_pfn, 1UL<<(32-PAGE_SHIFT)));
}
bool pfn_range_is_mapped(unsigned long start_pfn, unsigned long end_pfn)
{
int i;
for (i = 0; i < nr_pfn_mapped; i++)
if ((start_pfn >= pfn_mapped[i].start) &&
(end_pfn <= pfn_mapped[i].end))
return true;
return false;
}
/*
* Setup the direct mapping of the physical memory at PAGE_OFFSET.
* This runs before bootmem is initialized and gets pages directly from
* the physical memory. To access them they are temporarily mapped.
*/
unsigned long __init_refok init_memory_mapping(unsigned long start,
unsigned long end)
{
struct map_range mr[NR_RANGE_MR];
unsigned long ret = 0;
int nr_range, i;
pr_info("init_memory_mapping: [mem %#010lx-%#010lx]\n",
start, end - 1);
memset(mr, 0, sizeof(mr));
nr_range = split_mem_range(mr, 0, start, end);
for (i = 0; i < nr_range; i++)
ret = kernel_physical_mapping_init(mr[i].start, mr[i].end,
mr[i].page_size_mask);
add_pfn_range_mapped(start >> PAGE_SHIFT, ret >> PAGE_SHIFT);
return ret >> PAGE_SHIFT;
}
/*
* 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,
unsigned long r_end)
{
unsigned long start_pfn, end_pfn;
unsigned long mapped_ram_size = 0;
int i;
for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, NULL) {
u64 start = clamp_val(PFN_PHYS(start_pfn), r_start, r_end);
u64 end = clamp_val(PFN_PHYS(end_pfn), r_start, r_end);
if (start >= end)
continue;
/*
* if it is overlapping with brk pgt, we need to
* alloc pgt buf from memblock instead.
*/
can_use_brk_pgt = max(start, (u64)pgt_buf_end<<PAGE_SHIFT) >=
min(end, (u64)pgt_buf_top<<PAGE_SHIFT);
init_memory_mapping(start, end);
mapped_ram_size += end - start;
can_use_brk_pgt = true;
}
return mapped_ram_size;
}
static unsigned long __init get_new_step_size(unsigned long step_size)
{
/*
* 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;
/* xen has big range in reserved near end of ram, skip it at first.*/
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 */
step_size = PMD_SIZE;
max_pfn_mapped = 0; /* will get exact value next */
min_pfn_mapped = real_end >> PAGE_SHIFT;
last_start = start = real_end;
/*
* 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 < map_start)
start = map_start;
} else
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 = 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;
}
}
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) {
/* can we preseve max_low_pfn ?*/
max_low_pfn = max_pfn;
}
#else
early_ioremap_page_table_range_init();
#endif
load_cr3(swapper_pg_dir);
__flush_tlb_all();
early_memtest(0, max_pfn_mapped << PAGE_SHIFT);
}
/*
* devmem_is_allowed() checks to see if /dev/mem access to a certain address
* is valid. The argument is a physical page number.
*
*
* On x86, access has to be given to the first megabyte of ram because that area
* contains bios code and data regions used by X and dosemu and similar apps.
* Access has to be given to non-kernel-ram areas as well, these contain the PCI
* mmio resources as well as potential bios/acpi data regions.
*/
int devmem_is_allowed(unsigned long pagenr)
{
if (pagenr < 256)
return 1;
if (iomem_is_exclusive(pagenr << PAGE_SHIFT))
return 0;
if (!page_is_ram(pagenr))
return 1;
return 0;
}
void free_init_pages(char *what, unsigned long begin, unsigned long end)
{
unsigned long begin_aligned, end_aligned;
/* Make sure boundaries are page aligned */
begin_aligned = PAGE_ALIGN(begin);
end_aligned = end & PAGE_MASK;
if (WARN_ON(begin_aligned != begin || end_aligned != end)) {
begin = begin_aligned;
end = end_aligned;
}
if (begin >= end)
return;
/*
* If debugging page accesses then do not free this memory but
* mark them not present - any buggy init-section access will
* create a kernel page fault:
*/
#ifdef CONFIG_DEBUG_PAGEALLOC
printk(KERN_INFO "debug: unmapping init [mem %#010lx-%#010lx]\n",
begin, end - 1);
set_memory_np(begin, (end - begin) >> PAGE_SHIFT);
#else
/*
* We just marked the kernel text read only above, now that
* we are going to free part of that, we need to make that
* writeable and non-executable first.
*/
set_memory_nx(begin, (end - begin) >> PAGE_SHIFT);
set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
free_reserved_area((void *)begin, (void *)end, POISON_FREE_INITMEM, what);
#endif
}
void free_initmem(void)
{
free_init_pages("unused kernel",
(unsigned long)(&__init_begin),
(unsigned long)(&__init_end));
}
#ifdef CONFIG_BLK_DEV_INITRD
void __init free_initrd_mem(unsigned long start, unsigned long end)
{
#ifdef CONFIG_MICROCODE_EARLY
/*
* Remember, initrd memory may contain microcode or other useful things.
* Before we lose initrd mem, we need to find a place to hold them
* now that normal virtual memory is enabled.
*/
save_microcode_in_initrd();
#endif
/*
* end could be not aligned, and We can not align that,
* decompresser could be confused by aligned initrd_end
* We already reserve the end partial page before in
* - i386_start_kernel()
* - x86_64_start_kernel()
* - relocate_initrd()
* So here We can do PAGE_ALIGN() safely to get partial page to be freed
*/
free_init_pages("initrd", start, PAGE_ALIGN(end));
}
#endif
void __init zone_sizes_init(void)
{
unsigned long max_zone_pfns[MAX_NR_ZONES];
memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
#ifdef CONFIG_ZONE_DMA
max_zone_pfns[ZONE_DMA] = MAX_DMA_PFN;
#endif
#ifdef CONFIG_ZONE_DMA32
max_zone_pfns[ZONE_DMA32] = MAX_DMA32_PFN;
#endif
max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
#ifdef CONFIG_HIGHMEM
max_zone_pfns[ZONE_HIGHMEM] = max_pfn;
#endif
free_area_init_nodes(max_zone_pfns);
}