/*
* linux/arch/i386/mm/init.c
*
* Copyright (C) 1995 Linus Torvalds
*
* Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/ptrace.h>
#include <linux/mman.h>
#include <linux/mm.h>
#include <linux/hugetlb.h>
#include <linux/swap.h>
#include <linux/smp.h>
#include <linux/init.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/bootmem.h>
#include <linux/slab.h>
#include <linux/proc_fs.h>
#include <linux/efi.h>
#include <linux/memory_hotplug.h>
#include <linux/initrd.h>
#include <asm/processor.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/pgtable.h>
#include <asm/dma.h>
#include <asm/fixmap.h>
#include <asm/e820.h>
#include <asm/apic.h>
#include <asm/tlb.h>
#include <asm/tlbflush.h>
#include <asm/sections.h>
unsigned int __VMALLOC_RESERVE = 128 << 20;
DEFINE_PER_CPU(struct mmu_gather, mmu_gathers);
unsigned long highstart_pfn, highend_pfn;
static int noinline do_test_wp_bit(void);
/*
* Creates a middle page table and puts a pointer to it in the
* given global directory entry. This only returns the gd entry
* in non-PAE compilation mode, since the middle layer is folded.
*/
static pmd_t * __init one_md_table_init(pgd_t *pgd)
{
pud_t *pud;
pmd_t *pmd_table;
#ifdef CONFIG_X86_PAE
pmd_table = (pmd_t *) alloc_bootmem_low_pages(PAGE_SIZE);
set_pgd(pgd, __pgd(__pa(pmd_table) | _PAGE_PRESENT));
pud = pud_offset(pgd, 0);
if (pmd_table != pmd_offset(pud, 0))
BUG();
#else
pud = pud_offset(pgd, 0);
pmd_table = pmd_offset(pud, 0);
#endif
return pmd_table;
}
/*
* Create a page table and place a pointer to it in a middle page
* directory entry.
*/
static pte_t * __init one_page_table_init(pmd_t *pmd)
{
if (pmd_none(*pmd)) {
pte_t *page_table = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
if (page_table != pte_offset_kernel(pmd, 0))
BUG();
return page_table;
}
return pte_offset_kernel(pmd, 0);
}
/*
* This function initializes a certain range of kernel virtual memory
* with new bootmem page tables, everywhere page tables are missing in
* the given range.
*/
/*
* NOTE: The pagetables are allocated contiguous on the physical space
* so we can cache the place of the first one and move around without
* checking the pgd every time.
*/
static void __init page_table_range_init (unsigned long start, unsigned long end, pgd_t *pgd_base)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
int pgd_idx, pmd_idx;
unsigned long vaddr;
vaddr = start;
pgd_idx = pgd_index(vaddr);
pmd_idx = pmd_index(vaddr);
pgd = pgd_base + pgd_idx;
for ( ; (pgd_idx < PTRS_PER_PGD) && (vaddr != end); pgd++, pgd_idx++) {
if (pgd_none(*pgd))
one_md_table_init(pgd);
pud = pud_offset(pgd, vaddr);
pmd = pmd_offset(pud, vaddr);
for (; (pmd_idx < PTRS_PER_PMD) && (vaddr != end); pmd++, pmd_idx++) {
if (pmd_none(*pmd))
one_page_table_init(pmd);
vaddr += PMD_SIZE;
}
pmd_idx = 0;
}
}
static inline int is_kernel_text(unsigned long addr)
{
if (addr >= PAGE_OFFSET && addr <= (unsigned long)__init_end)
return 1;
return 0;
}
/*
* This maps the physical memory to kernel virtual address space, a total
* of max_low_pfn pages, by creating page tables starting from address
* PAGE_OFFSET.
*/
static void __init kernel_physical_mapping_init(pgd_t *pgd_base)
{
unsigned long pfn;
pgd_t *pgd;
pmd_t *pmd;
pte_t *pte;
int pgd_idx, pmd_idx, pte_ofs;
pgd_idx = pgd_index(PAGE_OFFSET);
pgd = pgd_base + pgd_idx;
pfn = 0;
for (; pgd_idx < PTRS_PER_PGD; pgd++, pgd_idx++) {
pmd = one_md_table_init(pgd);
if (pfn >= max_low_pfn)
continue;
for (pmd_idx = 0; pmd_idx < PTRS_PER_PMD && pfn < max_low_pfn; pmd++, pmd_idx++) {
unsigned int address = pfn * PAGE_SIZE + PAGE_OFFSET;
/* Map with big pages if possible, otherwise create normal page tables. */
if (cpu_has_pse) {
unsigned int address2 = (pfn + PTRS_PER_PTE - 1) * PAGE_SIZE + PAGE_OFFSET + PAGE_SIZE-1;
if (is_kernel_text(address) || is_kernel_text(address2))
set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE_EXEC));
else
set_pmd(pmd, pfn_pmd(pfn, PAGE_KERNEL_LARGE));
pfn += PTRS_PER_PTE;
} else {
pte = one_page_table_init(pmd);
for (pte_ofs = 0; pte_ofs < PTRS_PER_PTE && pfn < max_low_pfn; pte++, pfn++, pte_ofs++) {
if (is_kernel_text(address))
set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
else
set_pte(pte, pfn_pte(pfn, PAGE_KERNEL));
}
}
}
}
}
static inline int page_kills_ppro(unsigned long pagenr)
{
if (pagenr >= 0x70000 && pagenr <= 0x7003F)
return 1;
return 0;
}
extern int is_available_memory(efi_memory_desc_t *);
int page_is_ram(unsigned long pagenr)
{
int i;
unsigned long addr, end;
if (efi_enabled) {
efi_memory_desc_t *md;
void *p;
for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) {
md = p;
if (!is_available_memory(md))
continue;
addr = (md->phys_addr+PAGE_SIZE-1) >> PAGE_SHIFT;
end = (md->phys_addr + (md->num_pages << EFI_PAGE_SHIFT)) >> PAGE_SHIFT;
if ((pagenr >= addr) && (pagenr < end))
return 1;
}
return 0;
}
for (i = 0; i < e820.nr_map; i++) {
if (e820.map[i].type != E820_RAM) /* not usable memory */
continue;
/*
* !!!FIXME!!! Some BIOSen report areas as RAM that
* are not. Notably the 640->1Mb area. We need a sanity
* check here.
*/
addr = (e820.map[i].addr+PAGE_SIZE-1) >> PAGE_SHIFT;
end = (e820.map[i].addr+e820.map[i].size) >> PAGE_SHIFT;
if ((pagenr >= addr) && (pagenr < end))
return 1;
}
return 0;
}
#ifdef CONFIG_HIGHMEM
pte_t *kmap_pte;
pgprot_t kmap_prot;
#define kmap_get_fixmap_pte(vaddr) \
pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), vaddr), (vaddr)), (vaddr))
static void __init kmap_init(void)
{
unsigned long kmap_vstart;
/* cache the first kmap pte */
kmap_vstart = __fix_to_virt(FIX_KMAP_BEGIN);
kmap_pte = kmap_get_fixmap_pte(kmap_vstart);
kmap_prot = PAGE_KERNEL;
}
static void __init permanent_kmaps_init(pgd_t *pgd_base)
{
pgd_t *pgd;
pud_t *pud;
pmd_t *pmd;
pte_t *pte;
unsigned long vaddr;
vaddr = PKMAP_BASE;
page_table_range_init(vaddr, vaddr + PAGE_SIZE*LAST_PKMAP, pgd_base);
pgd = swapper_pg_dir + pgd_index(vaddr);
pud = pud_offset(pgd, vaddr);
pmd = pmd_offset(pud, vaddr);
pte = pte_offset_kernel(pmd, vaddr);
pkmap_page_table = pte;
}
static void __meminit free_new_highpage(struct page *page)
{
init_page_count(page);
__free_page(page);
totalhigh_pages++;
}
void __init add_one_highpage_init(struct page *page, int pfn, int bad_ppro)
{
if (page_is_ram(pfn) && !(bad_ppro && page_kills_ppro(pfn))) {
ClearPageReserved(page);
free_new_highpage(page);
} else
SetPageReserved(page);
}
static int add_one_highpage_hotplug(struct page *page, unsigned long pfn)
{
free_new_highpage(page);
totalram_pages++;
#ifdef CONFIG_FLATMEM
max_mapnr = max(pfn, max_mapnr);
#endif
num_physpages++;
return 0;
}
/*
* Not currently handling the NUMA case.
* Assuming single node and all memory that
* has been added dynamically that would be
* onlined here is in HIGHMEM
*/
void online_page(struct page *page)
{
ClearPageReserved(page);
add_one_highpage_hotplug(page, page_to_pfn(page));
}
#ifdef CONFIG_NUMA
extern void set_highmem_pages_init(int);
#else
static void __init set_highmem_pages_init(int bad_ppro)
{
int pfn;
for (pfn = highstart_pfn; pfn < highend_pfn; pfn++)
add_one_highpage_init(pfn_to_page(pfn), pfn, bad_ppro);
totalram_pages += totalhigh_pages;
}
#endif /* CONFIG_FLATMEM */
#else
#define kmap_init() do { } while (0)
#define permanent_kmaps_init(pgd_base) do { } while (0)
#define set_highmem_pages_init(bad_ppro) do { } while (0)
#endif /* CONFIG_HIGHMEM */
unsigned long long __PAGE_KERNEL = _PAGE_KERNEL;
EXPORT_SYMBOL(__PAGE_KERNEL);
unsigned long long __PAGE_KERNEL_EXEC = _PAGE_KERNEL_EXEC;
#ifdef CONFIG_NUMA
extern void __init remap_numa_kva(void);
#else
#define remap_numa_kva() do {} while (0)
#endif
static void __init pagetable_init (void)
{
unsigned long vaddr;
pgd_t *pgd_base = swapper_pg_dir;
#ifdef CONFIG_X86_PAE
int i;
/* Init entries of the first-level page table to the zero page */
for (i = 0; i < PTRS_PER_PGD; i++)
set_pgd(pgd_base + i, __pgd(__pa(empty_zero_page) | _PAGE_PRESENT));
#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);
__PAGE_KERNEL |= _PAGE_GLOBAL;
__PAGE_KERNEL_EXEC |= _PAGE_GLOBAL;
}
kernel_physical_mapping_init(pgd_base);
remap_numa_kva();
/*
* Fixed mappings, only the page table structure has to be
* created - mappings will be set by set_fixmap():
*/
vaddr = __fix_to_virt(__end_of_fixed_addresses - 1) & PMD_MASK;
page_table_range_init(vaddr, 0, pgd_base);
permanent_kmaps_init(pgd_base);
#ifdef CONFIG_X86_PAE
/*
* Add low memory identity-mappings - SMP needs it when
* starting up on an AP from real-mode. In the non-PAE
* case we already have these mappings through head.S.
* All user-space mappings are explicitly cleared after
* SMP startup.
*/
set_pgd(&pgd_base[0], pgd_base[USER_PTRS_PER_PGD]);
#endif
}
#ifdef CONFIG_SOFTWARE_SUSPEND
/*
* Swap suspend & friends need this for resume because things like the intel-agp
* driver might have split up a kernel 4MB mapping.
*/
char __nosavedata swsusp_pg_dir[PAGE_SIZE]
__attribute__ ((aligned (PAGE_SIZE)));
static inline void save_pg_dir(void)
{
memcpy(swsusp_pg_dir, swapper_pg_dir, PAGE_SIZE);
}
#else
static inline void save_pg_dir(void)
{
}
#endif
void zap_low_mappings (void)
{
int i;
save_pg_dir();
/*
* Zap initial low-memory mappings.
*
* Note that "pgd_clear()" doesn't do it for
* us, because pgd_clear() is a no-op on i386.
*/
for (i = 0; i < USER_PTRS_PER_PGD; i++)
#ifdef CONFIG_X86_PAE
set_pgd(swapper_pg_dir+i, __pgd(1 + __pa(empty_zero_page)));
#else
set_pgd(swapper_pg_dir+i, __pgd(0));
#endif
flush_tlb_all();
}
static int disable_nx __initdata = 0;
u64 __supported_pte_mask __read_mostly = ~_PAGE_NX;
/*
* noexec = on|off
*
* Control non executable mappings.
*
* on Enable
* off Disable
*/
void __init noexec_setup(const char *str)
{
if (!strncmp(str, "on",2) && cpu_has_nx) {
__supported_pte_mask |= _PAGE_NX;
disable_nx = 0;
} else if (!strncmp(str,"off",3)) {
disable_nx = 1;
__supported_pte_mask &= ~_PAGE_NX;
}
}
int nx_enabled = 0;
#ifdef CONFIG_X86_PAE
static void __init set_nx(void)
{
unsigned int v[4], l, h;
if (cpu_has_pae && (cpuid_eax(0x80000000) > 0x80000001)) {
cpuid(0x80000001, &v[0], &v[1], &v[2], &v[3]);
if ((v[3] & (1 << 20)) && !disable_nx) {
rdmsr(MSR_EFER, l, h);
l |= EFER_NX;
wrmsr(MSR_EFER, l, h);
nx_enabled = 1;
__supported_pte_mask |= _PAGE_NX;
}
}
}
/*
* Enables/disables executability of a given kernel page and
* returns the previous setting.
*/
int __init set_kernel_exec(unsigned long vaddr, int enable)
{
pte_t *pte;
int ret = 1;
if (!nx_enabled)
goto out;
pte = lookup_address(vaddr);
BUG_ON(!pte);
if (!pte_exec_kernel(*pte))
ret = 0;
if (enable)
pte->pte_high &= ~(1 << (_PAGE_BIT_NX - 32));
else
pte->pte_high |= 1 << (_PAGE_BIT_NX - 32);
__flush_tlb_all();
out:
return ret;
}
#endif
/*
* paging_init() sets up the page tables - note that the first 8MB are
* already mapped by head.S.
*
* This routines also unmaps the page at virtual kernel address 0, so
* that we can trap those pesky NULL-reference errors in the kernel.
*/
void __init paging_init(void)
{
#ifdef CONFIG_X86_PAE
set_nx();
if (nx_enabled)
printk("NX (Execute Disable) protection: active\n");
#endif
pagetable_init();
load_cr3(swapper_pg_dir);
#ifdef CONFIG_X86_PAE
/*
* We will bail out later - printk doesn't work right now so
* the user would just see a hanging kernel.
*/
if (cpu_has_pae)
set_in_cr4(X86_CR4_PAE);
#endif
__flush_tlb_all();
kmap_init();
}
/*
* Test if the WP bit works in supervisor mode. It isn't supported on 386's
* and also on some strange 486's (NexGen etc.). All 586+'s are OK. This
* used to involve black magic jumps to work around some nasty CPU bugs,
* but fortunately the switch to using exceptions got rid of all that.
*/
static void __init test_wp_bit(void)
{
printk("Checking if this processor honours the WP bit even in supervisor mode... ");
/* Any page-aligned address will do, the test is non-destructive */
__set_fixmap(FIX_WP_TEST, __pa(&swapper_pg_dir), PAGE_READONLY);
boot_cpu_data.wp_works_ok = do_test_wp_bit();
clear_fixmap(FIX_WP_TEST);
if (!boot_cpu_data.wp_works_ok) {
printk("No.\n");
#ifdef CONFIG_X86_WP_WORKS_OK
panic("This kernel doesn't support CPU's with broken WP. Recompile it for a 386!");
#endif
} else {
printk("Ok.\n");
}
}
static void __init set_max_mapnr_init(void)
{
#ifdef CONFIG_HIGHMEM
num_physpages = highend_pfn;
#else
num_physpages = max_low_pfn;
#endif
#ifdef CONFIG_FLATMEM
max_mapnr = num_physpages;
#endif
}
static struct kcore_list kcore_mem, kcore_vmalloc;
void __init mem_init(void)
{
extern int ppro_with_ram_bug(void);
int codesize, reservedpages, datasize, initsize;
int tmp;
int bad_ppro;
#ifdef CONFIG_FLATMEM
if (!mem_map)
BUG();
#endif
bad_ppro = ppro_with_ram_bug();
#ifdef CONFIG_HIGHMEM
/* check that fixmap and pkmap do not overlap */
if (PKMAP_BASE+LAST_PKMAP*PAGE_SIZE >= FIXADDR_START) {
printk(KERN_ERR "fixmap and kmap areas overlap - this will crash\n");
printk(KERN_ERR "pkstart: %lxh pkend: %lxh fixstart %lxh\n",
PKMAP_BASE, PKMAP_BASE+LAST_PKMAP*PAGE_SIZE, FIXADDR_START);
BUG();
}
#endif
set_max_mapnr_init();
#ifdef CONFIG_HIGHMEM
high_memory = (void *) __va(highstart_pfn * PAGE_SIZE - 1) + 1;
#else
high_memory = (void *) __va(max_low_pfn * PAGE_SIZE - 1) + 1;
#endif
/* this will put all low memory onto the freelists */
totalram_pages += free_all_bootmem();
reservedpages = 0;
for (tmp = 0; tmp < max_low_pfn; tmp++)
/*
* Only count reserved RAM pages
*/
if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
reservedpages++;
set_highmem_pages_init(bad_ppro);
codesize = (unsigned long) &_etext - (unsigned long) &_text;
datasize = (unsigned long) &_edata - (unsigned long) &_etext;
initsize = (unsigned long) &__init_end - (unsigned long) &__init_begin;
kclist_add(&kcore_mem, __va(0), max_low_pfn << PAGE_SHIFT);
kclist_add(&kcore_vmalloc, (void *)VMALLOC_START,
VMALLOC_END-VMALLOC_START);
printk(KERN_INFO "Memory: %luk/%luk available (%dk kernel code, %dk reserved, %dk data, %dk init, %ldk highmem)\n",
(unsigned long) nr_free_pages() << (PAGE_SHIFT-10),
num_physpages << (PAGE_SHIFT-10),
codesize >> 10,
reservedpages << (PAGE_SHIFT-10),
datasize >> 10,
initsize >> 10,
(unsigned long) (totalhigh_pages << (PAGE_SHIFT-10))
);
#ifdef CONFIG_X86_PAE
if (!cpu_has_pae)
panic("cannot execute a PAE-enabled kernel on a PAE-less CPU!");
#endif
if (boot_cpu_data.wp_works_ok < 0)
test_wp_bit();
/*
* Subtle. SMP is doing it's boot stuff late (because it has to
* fork idle threads) - but it also needs low mappings for the
* protected-mode entry to work. We zap these entries only after
* the WP-bit has been tested.
*/
#ifndef CONFIG_SMP
zap_low_mappings();
#endif
}
/*
* this is for the non-NUMA, single node SMP system case.
* Specifically, in the case of x86, we will always add
* memory to the highmem for now.
*/
#ifndef CONFIG_NEED_MULTIPLE_NODES
int add_memory(u64 start, u64 size)
{
struct pglist_data *pgdata = &contig_page_data;
struct zone *zone = pgdata->node_zones + MAX_NR_ZONES-1;
unsigned long start_pfn = start >> PAGE_SHIFT;
unsigned long nr_pages = size >> PAGE_SHIFT;
return __add_pages(zone, start_pfn, nr_pages);
}
int remove_memory(u64 start, u64 size)
{
return -EINVAL;
}
#endif
kmem_cache_t *pgd_cache;
kmem_cache_t *pmd_cache;
void __init pgtable_cache_init(void)
{
if (PTRS_PER_PMD > 1) {
pmd_cache = kmem_cache_create("pmd",
PTRS_PER_PMD*sizeof(pmd_t),
PTRS_PER_PMD*sizeof(pmd_t),
0,
pmd_ctor,
NULL);
if (!pmd_cache)
panic("pgtable_cache_init(): cannot create pmd cache");
}
pgd_cache = kmem_cache_create("pgd",
PTRS_PER_PGD*sizeof(pgd_t),
PTRS_PER_PGD*sizeof(pgd_t),
0,
pgd_ctor,
PTRS_PER_PMD == 1 ? pgd_dtor : NULL);
if (!pgd_cache)
panic("pgtable_cache_init(): Cannot create pgd cache");
}
/*
* This function cannot be __init, since exceptions don't work in that
* section. Put this after the callers, so that it cannot be inlined.
*/
static int noinline do_test_wp_bit(void)
{
char tmp_reg;
int flag;
__asm__ __volatile__(
" movb %0,%1 \n"
"1: movb %1,%0 \n"
" xorl %2,%2 \n"
"2: \n"
".section __ex_table,\"a\"\n"
" .align 4 \n"
" .long 1b,2b \n"
".previous \n"
:"=m" (*(char *)fix_to_virt(FIX_WP_TEST)),
"=q" (tmp_reg),
"=r" (flag)
:"2" (1)
:"memory");
return flag;
}
#ifdef CONFIG_DEBUG_RODATA
extern char __start_rodata, __end_rodata;
void mark_rodata_ro(void)
{
unsigned long addr = (unsigned long)&__start_rodata;
for (; addr < (unsigned long)&__end_rodata; addr += PAGE_SIZE)
change_page_attr(virt_to_page(addr), 1, PAGE_KERNEL_RO);
printk ("Write protecting the kernel read-only data: %luk\n",
(unsigned long)(&__end_rodata - &__start_rodata) >> 10);
/*
* change_page_attr() requires a global_flush_tlb() call after it.
* We do this after the printk so that if something went wrong in the
* change, the printk gets out at least to give a better debug hint
* of who is the culprit.
*/
global_flush_tlb();
}
#endif
void free_init_pages(char *what, unsigned long begin, unsigned long end)
{
unsigned long addr;
for (addr = begin; addr < end; addr += PAGE_SIZE) {
ClearPageReserved(virt_to_page(addr));
init_page_count(virt_to_page(addr));
memset((void *)addr, 0xcc, PAGE_SIZE);
free_page(addr);
totalram_pages++;
}
printk(KERN_INFO "Freeing %s: %ldk freed\n", what, (end - begin) >> 10);
}
void free_initmem(void)
{
free_init_pages("unused kernel memory",
(unsigned long)(&__init_begin),
(unsigned long)(&__init_end));
}
#ifdef CONFIG_BLK_DEV_INITRD
void free_initrd_mem(unsigned long start, unsigned long end)
{
free_init_pages("initrd memory", start, end);
}
#endif
