#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/mm.h>
+#include <linux/interrupt.h>
+#include <linux/seq_file.h>
+#include <linux/debugfs.h>
#include <asm/e820.h>
#include <asm/processor.h>
#include <asm/sections.h>
#include <asm/uaccess.h>
#include <asm/pgalloc.h>
+#include <asm/proto.h>
+/*
+ * The current flushing context - we pass it instead of 5 arguments:
+ */
struct cpa_data {
unsigned long vaddr;
pgprot_t mask_set;
pgprot_t mask_clr;
int numpages;
int flushtlb;
+ unsigned long pfn;
};
-enum {
- CPA_NO_SPLIT = 0,
- CPA_SPLIT,
-};
+#ifdef CONFIG_X86_64
+
+static inline unsigned long highmap_start_pfn(void)
+{
+ return __pa(_text) >> PAGE_SHIFT;
+}
+
+static inline unsigned long highmap_end_pfn(void)
+{
+ return __pa(round_up((unsigned long)_end, PMD_SIZE)) >> PAGE_SHIFT;
+}
+
+#endif
+
+#ifdef CONFIG_DEBUG_PAGEALLOC
+# define debug_pagealloc 1
+#else
+# define debug_pagealloc 0
+#endif
static inline int
within(unsigned long addr, unsigned long start, unsigned long end)
/*
* Only flush present addresses:
*/
- if (pte && pte_present(*pte))
+ if (pte && (pte_val(*pte) & _PAGE_PRESENT))
clflush_cache_range((void *) addr, PAGE_SIZE);
}
}
-#define HIGH_MAP_START __START_KERNEL_map
-#define HIGH_MAP_END (__START_KERNEL_map + KERNEL_TEXT_SIZE)
-
-
-/*
- * Converts a virtual address to a X86-64 highmap address
- */
-static unsigned long virt_to_highmap(void *address)
-{
-#ifdef CONFIG_X86_64
- return __pa((unsigned long)address) + HIGH_MAP_START - phys_base;
-#else
- return (unsigned long)address;
-#endif
-}
-
/*
* Certain areas of memory on x86 require very specific protection flags,
* for example the BIOS area or kernel text. Callers don't always get this
* right (again, ioremap() on BIOS memory is not uncommon) so this function
* checks and fixes these known static required protection bits.
*/
-static inline pgprot_t static_protections(pgprot_t prot, unsigned long address)
+static inline pgprot_t static_protections(pgprot_t prot, unsigned long address,
+ unsigned long pfn)
{
pgprot_t forbidden = __pgprot(0);
* The BIOS area between 640k and 1Mb needs to be executable for
* PCI BIOS based config access (CONFIG_PCI_GOBIOS) support.
*/
- if (within(__pa(address), BIOS_BEGIN, BIOS_END))
+ if (within(pfn, BIOS_BEGIN >> PAGE_SHIFT, BIOS_END >> PAGE_SHIFT))
pgprot_val(forbidden) |= _PAGE_NX;
/*
* The kernel text needs to be executable for obvious reasons
- * Does not cover __inittext since that is gone later on
+ * Does not cover __inittext since that is gone later on. On
+ * 64bit we do not enforce !NX on the low mapping
*/
if (within(address, (unsigned long)_text, (unsigned long)_etext))
pgprot_val(forbidden) |= _PAGE_NX;
- /*
- * Do the same for the x86-64 high kernel mapping
- */
- if (within(address, virt_to_highmap(_text), virt_to_highmap(_etext)))
- pgprot_val(forbidden) |= _PAGE_NX;
-
-#ifdef CONFIG_DEBUG_RODATA
- /* The .rodata section needs to be read-only */
- if (within(address, (unsigned long)__start_rodata,
- (unsigned long)__end_rodata))
- pgprot_val(forbidden) |= _PAGE_RW;
/*
- * Do the same for the x86-64 high kernel mapping
+ * The .rodata section needs to be read-only. Using the pfn
+ * catches all aliases.
*/
- if (within(address, virt_to_highmap(__start_rodata),
- virt_to_highmap(__end_rodata)))
+ if (within(pfn, __pa((unsigned long)__start_rodata) >> PAGE_SHIFT,
+ __pa((unsigned long)__end_rodata) >> PAGE_SHIFT))
pgprot_val(forbidden) |= _PAGE_RW;
-#endif
prot = __pgprot(pgprot_val(prot) & ~pgprot_val(forbidden));
* or when the present bit is not set. Otherwise we would return a
* pointer to a nonexisting mapping.
*/
-pte_t *lookup_address(unsigned long address, int *level)
+pte_t *lookup_address(unsigned long address, unsigned int *level)
{
pgd_t *pgd = pgd_offset_k(address);
pud_t *pud;
if (pgd_none(*pgd))
return NULL;
+
pud = pud_offset(pgd, address);
if (pud_none(*pud))
return NULL;
+
+ *level = PG_LEVEL_1G;
+ if (pud_large(*pud) || !pud_present(*pud))
+ return (pte_t *)pud;
+
pmd = pmd_offset(pud, address);
if (pmd_none(*pmd))
return NULL;
return (pte_t *)pmd;
*level = PG_LEVEL_4K;
+
return pte_offset_kernel(pmd, address);
}
+/*
+ * Set the new pmd in all the pgds we know about:
+ */
static void __set_pmd_pte(pte_t *kpte, unsigned long address, pte_t pte)
{
/* change init_mm */
#endif
}
-static int try_preserve_large_page(pte_t *kpte, unsigned long address,
- struct cpa_data *cpa)
+static int
+try_preserve_large_page(pte_t *kpte, unsigned long address,
+ struct cpa_data *cpa)
{
- unsigned long nextpage_addr, numpages, pmask, psize, flags;
+ unsigned long nextpage_addr, numpages, pmask, psize, flags, addr, pfn;
pte_t new_pte, old_pte, *tmp;
pgprot_t old_prot, new_prot;
- int level, res = CPA_SPLIT;
-
- /*
- * An Athlon 64 X2 showed hard hangs if we tried to preserve
- * largepages and changed the PSE entry from RW to RO.
- *
- * As AMD CPUs have a long series of erratas in this area,
- * (and none of the known ones seem to explain this hang),
- * disable this code until the hang can be debugged:
- */
- if (boot_cpu_data.x86_vendor == X86_VENDOR_AMD)
- return res;
+ int i, do_split = 1;
+ unsigned int level;
spin_lock_irqsave(&pgd_lock, flags);
/*
psize = PMD_PAGE_SIZE;
pmask = PMD_PAGE_MASK;
break;
+#ifdef CONFIG_X86_64
case PG_LEVEL_1G:
+ psize = PUD_PAGE_SIZE;
+ pmask = PUD_PAGE_MASK;
+ break;
+#endif
default:
- res = -EINVAL;
+ do_split = -EINVAL;
goto out_unlock;
}
pgprot_val(new_prot) &= ~pgprot_val(cpa->mask_clr);
pgprot_val(new_prot) |= pgprot_val(cpa->mask_set);
- new_prot = static_protections(new_prot, address);
+
+ /*
+ * old_pte points to the large page base address. So we need
+ * to add the offset of the virtual address:
+ */
+ pfn = pte_pfn(old_pte) + ((address & (psize - 1)) >> PAGE_SHIFT);
+ cpa->pfn = pfn;
+
+ new_prot = static_protections(new_prot, address, pfn);
+
+ /*
+ * We need to check the full range, whether
+ * static_protection() requires a different pgprot for one of
+ * the pages in the range we try to preserve:
+ */
+ addr = address + PAGE_SIZE;
+ pfn++;
+ for (i = 1; i < cpa->numpages; i++, addr += PAGE_SIZE, pfn++) {
+ pgprot_t chk_prot = static_protections(new_prot, addr, pfn);
+
+ if (pgprot_val(chk_prot) != pgprot_val(new_prot))
+ goto out_unlock;
+ }
/*
* If there are no changes, return. maxpages has been updated
* above:
*/
if (pgprot_val(new_prot) == pgprot_val(old_prot)) {
- res = CPA_NO_SPLIT;
+ do_split = 0;
goto out_unlock;
}
new_pte = pfn_pte(pte_pfn(old_pte), canon_pgprot(new_prot));
__set_pmd_pte(kpte, address, new_pte);
cpa->flushtlb = 1;
- res = CPA_NO_SPLIT;
+ do_split = 0;
}
out_unlock:
spin_unlock_irqrestore(&pgd_lock, flags);
- return res;
+
+ return do_split;
+}
+
+static LIST_HEAD(page_pool);
+static unsigned long pool_size, pool_pages, pool_low;
+static unsigned long pool_used, pool_failed;
+
+static void cpa_fill_pool(struct page **ret)
+{
+ gfp_t gfp = GFP_KERNEL;
+ unsigned long flags;
+ struct page *p;
+
+ /*
+ * Avoid recursion (on debug-pagealloc) and also signal
+ * our priority to get to these pagetables:
+ */
+ if (current->flags & PF_MEMALLOC)
+ return;
+ current->flags |= PF_MEMALLOC;
+
+ /*
+ * Allocate atomically from atomic contexts:
+ */
+ if (in_atomic() || irqs_disabled() || debug_pagealloc)
+ gfp = GFP_ATOMIC | __GFP_NORETRY | __GFP_NOWARN;
+
+ while (pool_pages < pool_size || (ret && !*ret)) {
+ p = alloc_pages(gfp, 0);
+ if (!p) {
+ pool_failed++;
+ break;
+ }
+ /*
+ * If the call site needs a page right now, provide it:
+ */
+ if (ret && !*ret) {
+ *ret = p;
+ continue;
+ }
+ spin_lock_irqsave(&pgd_lock, flags);
+ list_add(&p->lru, &page_pool);
+ pool_pages++;
+ spin_unlock_irqrestore(&pgd_lock, flags);
+ }
+
+ current->flags &= ~PF_MEMALLOC;
+}
+
+#define SHIFT_MB (20 - PAGE_SHIFT)
+#define ROUND_MB_GB ((1 << 10) - 1)
+#define SHIFT_MB_GB 10
+#define POOL_PAGES_PER_GB 16
+
+void __init cpa_init(void)
+{
+ struct sysinfo si;
+ unsigned long gb;
+
+ si_meminfo(&si);
+ /*
+ * Calculate the number of pool pages:
+ *
+ * Convert totalram (nr of pages) to MiB and round to the next
+ * GiB. Shift MiB to Gib and multiply the result by
+ * POOL_PAGES_PER_GB:
+ */
+ if (debug_pagealloc) {
+ gb = ((si.totalram >> SHIFT_MB) + ROUND_MB_GB) >> SHIFT_MB_GB;
+ pool_size = POOL_PAGES_PER_GB * gb;
+ } else {
+ pool_size = 1;
+ }
+ pool_low = pool_size;
+
+ cpa_fill_pool(NULL);
+ printk(KERN_DEBUG
+ "CPA: page pool initialized %lu of %lu pages preallocated\n",
+ pool_pages, pool_size);
}
static int split_large_page(pte_t *kpte, unsigned long address)
{
- pgprot_t ref_prot;
- gfp_t gfp_flags = GFP_KERNEL;
- unsigned long flags, addr, pfn;
+ unsigned long flags, pfn, pfninc = 1;
+ unsigned int i, level;
pte_t *pbase, *tmp;
+ pgprot_t ref_prot;
struct page *base;
- unsigned int i, level;
-
-#ifdef CONFIG_DEBUG_PAGEALLOC
- gfp_flags = GFP_ATOMIC | __GFP_NOWARN;
-#endif
- base = alloc_pages(gfp_flags, 0);
- if (!base)
- return -ENOMEM;
+ /*
+ * Get a page from the pool. The pool list is protected by the
+ * pgd_lock, which we have to take anyway for the split
+ * operation:
+ */
spin_lock_irqsave(&pgd_lock, flags);
+ if (list_empty(&page_pool)) {
+ spin_unlock_irqrestore(&pgd_lock, flags);
+ base = NULL;
+ cpa_fill_pool(&base);
+ if (!base)
+ return -ENOMEM;
+ spin_lock_irqsave(&pgd_lock, flags);
+ } else {
+ base = list_first_entry(&page_pool, struct page, lru);
+ list_del(&base->lru);
+ pool_pages--;
+
+ if (pool_pages < pool_low)
+ pool_low = pool_pages;
+ }
+
/*
* Check for races, another CPU might have split this page
* up for us already:
*/
tmp = lookup_address(address, &level);
- if (tmp != kpte) {
- WARN_ON_ONCE(1);
+ if (tmp != kpte)
goto out_unlock;
- }
- address = __pa(address);
- addr = address & PMD_PAGE_MASK;
pbase = (pte_t *)page_address(base);
#ifdef CONFIG_X86_32
paravirt_alloc_pt(&init_mm, page_to_pfn(base));
#endif
ref_prot = pte_pgprot(pte_clrhuge(*kpte));
+#ifdef CONFIG_X86_64
+ if (level == PG_LEVEL_1G) {
+ pfninc = PMD_PAGE_SIZE >> PAGE_SHIFT;
+ pgprot_val(ref_prot) |= _PAGE_PSE;
+ }
+#endif
+
/*
* Get the target pfn from the original entry:
*/
pfn = pte_pfn(*kpte);
- for (i = 0; i < PTRS_PER_PTE; i++, pfn++)
+ for (i = 0; i < PTRS_PER_PTE; i++, pfn += pfninc)
set_pte(&pbase[i], pfn_pte(pfn, ref_prot));
/*
base = NULL;
out_unlock:
+ /*
+ * If we dropped out via the lookup_address check under
+ * pgd_lock then stick the page back into the pool:
+ */
+ if (base) {
+ list_add(&base->lru, &page_pool);
+ pool_pages++;
+ } else
+ pool_used++;
spin_unlock_irqrestore(&pgd_lock, flags);
- if (base)
- __free_pages(base, 0);
-
return 0;
}
-static int __change_page_attr(unsigned long address, struct cpa_data *cpa)
+static int __change_page_attr(struct cpa_data *cpa, int primary)
{
- struct page *kpte_page;
- int level, res;
- pte_t *kpte;
+ unsigned long address = cpa->vaddr;
+ int do_split, err;
+ unsigned int level;
+ pte_t *kpte, old_pte;
repeat:
kpte = lookup_address(address, &level);
if (!kpte)
- return -EINVAL;
+ return primary ? -EINVAL : 0;
- kpte_page = virt_to_page(kpte);
- BUG_ON(PageLRU(kpte_page));
- BUG_ON(PageCompound(kpte_page));
+ old_pte = *kpte;
+ if (!pte_val(old_pte)) {
+ if (!primary)
+ return 0;
+ printk(KERN_WARNING "CPA: called for zero pte. "
+ "vaddr = %lx cpa->vaddr = %lx\n", address,
+ cpa->vaddr);
+ WARN_ON(1);
+ return -EINVAL;
+ }
if (level == PG_LEVEL_4K) {
- pte_t new_pte, old_pte = *kpte;
+ pte_t new_pte;
pgprot_t new_prot = pte_pgprot(old_pte);
-
- if(!pte_val(old_pte)) {
- printk(KERN_WARNING "CPA: called for zero pte. "
- "vaddr = %lx cpa->vaddr = %lx\n", address,
- cpa->vaddr);
- WARN_ON(1);
- return -EINVAL;
- }
+ unsigned long pfn = pte_pfn(old_pte);
pgprot_val(new_prot) &= ~pgprot_val(cpa->mask_clr);
pgprot_val(new_prot) |= pgprot_val(cpa->mask_set);
- new_prot = static_protections(new_prot, address);
+ new_prot = static_protections(new_prot, address, pfn);
/*
* We need to keep the pfn from the existing PTE,
* after all we're only going to change it's attributes
* not the memory it points to
*/
- new_pte = pfn_pte(pte_pfn(old_pte), canon_pgprot(new_prot));
-
+ new_pte = pfn_pte(pfn, canon_pgprot(new_prot));
+ cpa->pfn = pfn;
/*
* Do we really change anything ?
*/
* Check, whether we can keep the large page intact
* and just change the pte:
*/
- res = try_preserve_large_page(kpte, address, cpa);
- if (res < 0)
- return res;
-
+ do_split = try_preserve_large_page(kpte, address, cpa);
/*
* When the range fits into the existing large page,
* return. cp->numpages and cpa->tlbflush have been updated in
* try_large_page:
*/
- if (res == CPA_NO_SPLIT)
- return 0;
+ if (do_split <= 0)
+ return do_split;
/*
* We have to split the large page:
*/
- res = split_large_page(kpte, address);
- if (res)
- return res;
- cpa->flushtlb = 1;
- goto repeat;
+ err = split_large_page(kpte, address);
+ if (!err) {
+ cpa->flushtlb = 1;
+ goto repeat;
+ }
+
+ return err;
}
-/**
- * change_page_attr_addr - Change page table attributes in linear mapping
- * @address: Virtual address in linear mapping.
- * @prot: New page table attribute (PAGE_*)
- *
- * Change page attributes of a page in the direct mapping. This is a variant
- * of change_page_attr() that also works on memory holes that do not have
- * mem_map entry (pfn_valid() is false).
- *
- * See change_page_attr() documentation for more details.
- *
- * Modules and drivers should use the set_memory_* APIs instead.
- */
+static int __change_page_attr_set_clr(struct cpa_data *cpa, int checkalias);
-static int change_page_attr_addr(struct cpa_data *cpa)
+static int cpa_process_alias(struct cpa_data *cpa)
{
- int err;
- unsigned long address = cpa->vaddr;
+ struct cpa_data alias_cpa;
+ int ret = 0;
-#ifdef CONFIG_X86_64
- unsigned long phys_addr = __pa(address);
+ if (cpa->pfn > max_pfn_mapped)
+ return 0;
/*
- * If we are inside the high mapped kernel range, then we
- * fixup the low mapping first. __va() returns the virtual
- * address in the linear mapping:
+ * No need to redo, when the primary call touched the direct
+ * mapping already:
*/
- if (within(address, HIGH_MAP_START, HIGH_MAP_END))
- address = (unsigned long) __va(phys_addr);
-#endif
+ if (!within(cpa->vaddr, PAGE_OFFSET,
+ PAGE_OFFSET + (max_pfn_mapped << PAGE_SHIFT))) {
- err = __change_page_attr(address, cpa);
- if (err)
- return err;
+ alias_cpa = *cpa;
+ alias_cpa.vaddr = (unsigned long) __va(cpa->pfn << PAGE_SHIFT);
+
+ ret = __change_page_attr_set_clr(&alias_cpa, 0);
+ }
#ifdef CONFIG_X86_64
+ if (ret)
+ return ret;
+ /*
+ * No need to redo, when the primary call touched the high
+ * mapping already:
+ */
+ if (within(cpa->vaddr, (unsigned long) _text, (unsigned long) _end))
+ return 0;
+
/*
* If the physical address is inside the kernel map, we need
* to touch the high mapped kernel as well:
*/
- if (within(phys_addr, 0, KERNEL_TEXT_SIZE)) {
- /*
- * Calc the high mapping address. See __phys_addr()
- * for the non obvious details.
- *
- * Note that NX and other required permissions are
- * checked in static_protections().
- */
- address = phys_addr + HIGH_MAP_START - phys_base;
+ if (!within(cpa->pfn, highmap_start_pfn(), highmap_end_pfn()))
+ return 0;
- /*
- * Our high aliases are imprecise, because we check
- * everything between 0 and KERNEL_TEXT_SIZE, so do
- * not propagate lookup failures back to users:
- */
- __change_page_attr(address, cpa);
- }
+ alias_cpa = *cpa;
+ alias_cpa.vaddr =
+ (cpa->pfn << PAGE_SHIFT) + __START_KERNEL_map - phys_base;
+
+ /*
+ * The high mapping range is imprecise, so ignore the return value.
+ */
+ __change_page_attr_set_clr(&alias_cpa, 0);
#endif
- return err;
+ return ret;
}
-static int __change_page_attr_set_clr(struct cpa_data *cpa)
+static int __change_page_attr_set_clr(struct cpa_data *cpa, int checkalias)
{
int ret, numpages = cpa->numpages;
* preservation check.
*/
cpa->numpages = numpages;
- ret = change_page_attr_addr(cpa);
+
+ ret = __change_page_attr(cpa, checkalias);
if (ret)
return ret;
+ if (checkalias) {
+ ret = cpa_process_alias(cpa);
+ if (ret)
+ return ret;
+ }
+
/*
* Adjust the number of pages with the result of the
* CPA operation. Either a large page has been
pgprot_t mask_set, pgprot_t mask_clr)
{
struct cpa_data cpa;
- int ret, cache;
+ int ret, cache, checkalias;
/*
* Check, if we are requested to change a not supported
if (!pgprot_val(mask_set) && !pgprot_val(mask_clr))
return 0;
+ /* Ensure we are PAGE_SIZE aligned */
+ if (addr & ~PAGE_MASK) {
+ addr &= PAGE_MASK;
+ /*
+ * People should not be passing in unaligned addresses:
+ */
+ WARN_ON_ONCE(1);
+ }
+
cpa.vaddr = addr;
cpa.numpages = numpages;
cpa.mask_set = mask_set;
cpa.mask_clr = mask_clr;
cpa.flushtlb = 0;
- ret = __change_page_attr_set_clr(&cpa);
+ /* No alias checking for _NX bit modifications */
+ checkalias = (pgprot_val(mask_set) | pgprot_val(mask_clr)) != _PAGE_NX;
+
+ ret = __change_page_attr_set_clr(&cpa, checkalias);
/*
* Check whether we really changed something:
*/
if (!cpa.flushtlb)
- return ret;
+ goto out;
/*
* No need to flush, when we did not set any of the caching
else
cpa_flush_all(cache);
+out:
+ cpa_fill_pool(NULL);
+
return ret;
}
int set_memory_uc(unsigned long addr, int numpages)
{
return change_page_attr_set(addr, numpages,
- __pgprot(_PAGE_PCD | _PAGE_PWT));
+ __pgprot(_PAGE_CACHE_UC));
}
EXPORT_SYMBOL(set_memory_uc);
int set_memory_wb(unsigned long addr, int numpages)
{
return change_page_attr_clear(addr, numpages,
- __pgprot(_PAGE_PCD | _PAGE_PWT));
+ __pgprot(_PAGE_CACHE_MASK));
}
EXPORT_SYMBOL(set_memory_wb);
.mask_set = __pgprot(_PAGE_PRESENT | _PAGE_RW),
.mask_clr = __pgprot(0)};
- return __change_page_attr_set_clr(&cpa);
+ return __change_page_attr_set_clr(&cpa, 1);
}
static int __set_pages_np(struct page *page, int numpages)
.mask_set = __pgprot(0),
.mask_clr = __pgprot(_PAGE_PRESENT | _PAGE_RW)};
- return __change_page_attr_set_clr(&cpa);
+ return __change_page_attr_set_clr(&cpa, 1);
}
void kernel_map_pages(struct page *page, int numpages, int enable)
return;
/*
- * The return value is ignored - the calls cannot fail,
- * large pages are disabled at boot time:
+ * The return value is ignored as the calls cannot fail.
+ * Large pages are kept enabled at boot time, and are
+ * split up quickly with DEBUG_PAGEALLOC. If a splitup
+ * fails here (due to temporary memory shortage) no damage
+ * is done because we just keep the largepage intact up
+ * to the next attempt when it will likely be split up:
*/
if (enable)
__set_pages_p(page, numpages);
* but that can deadlock->flush only current cpu:
*/
__flush_tlb_all();
+
+ /*
+ * Try to refill the page pool here. We can do this only after
+ * the tlb flush.
+ */
+ cpa_fill_pool(NULL);
+}
+
+#ifdef CONFIG_DEBUG_FS
+static int dpa_show(struct seq_file *m, void *v)
+{
+ seq_puts(m, "DEBUG_PAGEALLOC\n");
+ seq_printf(m, "pool_size : %lu\n", pool_size);
+ seq_printf(m, "pool_pages : %lu\n", pool_pages);
+ seq_printf(m, "pool_low : %lu\n", pool_low);
+ seq_printf(m, "pool_used : %lu\n", pool_used);
+ seq_printf(m, "pool_failed : %lu\n", pool_failed);
+
+ return 0;
+}
+
+static int dpa_open(struct inode *inode, struct file *filp)
+{
+ return single_open(filp, dpa_show, NULL);
}
+
+static const struct file_operations dpa_fops = {
+ .open = dpa_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+};
+
+int __init debug_pagealloc_proc_init(void)
+{
+ struct dentry *de;
+
+ de = debugfs_create_file("debug_pagealloc", 0600, NULL, NULL,
+ &dpa_fops);
+ if (!de)
+ return -ENOMEM;
+
+ return 0;
+}
+__initcall(debug_pagealloc_proc_init);
#endif
+#ifdef CONFIG_HIBERNATION
+
+bool kernel_page_present(struct page *page)
+{
+ unsigned int level;
+ pte_t *pte;
+
+ if (PageHighMem(page))
+ return false;
+
+ pte = lookup_address((unsigned long)page_address(page), &level);
+ return (pte_val(*pte) & _PAGE_PRESENT);
+}
+
+#endif /* CONFIG_HIBERNATION */
+
+#endif /* CONFIG_DEBUG_PAGEALLOC */
+
/*
* The testcases use internal knowledge of the implementation that shouldn't
* be exposed to the rest of the kernel. Include these directly here.
Code Review / linux-2.6.git / blobdiff