#include <asm/uaccess.h>
#include <asm/pgalloc.h>
+struct cpa_data {
+ unsigned long vaddr;
+ pgprot_t mask_set;
+ pgprot_t mask_clr;
+ int numpages;
+ int flushtlb;
+};
+
+enum {
+ CPA_NO_SPLIT = 0,
+ CPA_SPLIT,
+};
+
static inline int
within(unsigned long addr, unsigned long start, unsigned long end)
{
static void __cpa_flush_all(void *arg)
{
+ unsigned long cache = (unsigned long)arg;
+
/*
* Flush all to work around Errata in early athlons regarding
* large page flushing.
*/
__flush_tlb_all();
- if (boot_cpu_data.x86_model >= 4)
+ if (cache && boot_cpu_data.x86_model >= 4)
wbinvd();
}
-static void cpa_flush_all(void)
+static void cpa_flush_all(unsigned long cache)
{
BUG_ON(irqs_disabled());
- on_each_cpu(__cpa_flush_all, NULL, 1, 1);
+ on_each_cpu(__cpa_flush_all, (void *) cache, 1, 1);
}
static void __cpa_flush_range(void *arg)
__flush_tlb_all();
}
-static void cpa_flush_range(unsigned long start, int numpages)
+static void cpa_flush_range(unsigned long start, int numpages, int cache)
{
unsigned int i, level;
unsigned long addr;
on_each_cpu(__cpa_flush_range, NULL, 1, 1);
+ if (!cache)
+ return;
+
/*
* We only need to flush on one CPU,
* clflush is a MESI-coherent instruction that
/*
* Only flush present addresses:
*/
- if (pte && pte_present(*pte))
+ if (pte && (pte_val(*pte) & _PAGE_PRESENT))
clflush_cache_range((void *) addr, PAGE_SIZE);
}
}
return prot;
}
+/*
+ * Lookup the page table entry for a virtual address. Return a pointer
+ * to the entry and the level of the mapping.
+ *
+ * Note: We return pud and pmd either when the entry is marked large
+ * 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)
{
pgd_t *pgd = pgd_offset_k(address);
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;
*level = PG_LEVEL_2M;
- if (pmd_large(*pmd))
+ if (pmd_large(*pmd) || !pmd_present(*pmd))
return (pte_t *)pmd;
*level = PG_LEVEL_4K;
#endif
}
+static int try_preserve_large_page(pte_t *kpte, unsigned long address,
+ struct cpa_data *cpa)
+{
+ unsigned long nextpage_addr, numpages, pmask, psize, flags;
+ 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;
+
+ spin_lock_irqsave(&pgd_lock, flags);
+ /*
+ * Check for races, another CPU might have split this page
+ * up already:
+ */
+ tmp = lookup_address(address, &level);
+ if (tmp != kpte)
+ goto out_unlock;
+
+ switch (level) {
+ case PG_LEVEL_2M:
+ psize = PMD_PAGE_SIZE;
+ pmask = PMD_PAGE_MASK;
+ break;
+ case PG_LEVEL_1G:
+ default:
+ res = -EINVAL;
+ goto out_unlock;
+ }
+
+ /*
+ * Calculate the number of pages, which fit into this large
+ * page starting at address:
+ */
+ nextpage_addr = (address + psize) & pmask;
+ numpages = (nextpage_addr - address) >> PAGE_SHIFT;
+ if (numpages < cpa->numpages)
+ cpa->numpages = numpages;
+
+ /*
+ * We are safe now. Check whether the new pgprot is the same:
+ */
+ old_pte = *kpte;
+ old_prot = new_prot = pte_pgprot(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);
+
+ /*
+ * If there are no changes, return. maxpages has been updated
+ * above:
+ */
+ if (pgprot_val(new_prot) == pgprot_val(old_prot)) {
+ res = CPA_NO_SPLIT;
+ goto out_unlock;
+ }
+
+ /*
+ * We need to change the attributes. Check, whether we can
+ * change the large page in one go. We request a split, when
+ * the address is not aligned and the number of pages is
+ * smaller than the number of pages in the large page. Note
+ * that we limited the number of possible pages already to
+ * the number of pages in the large page.
+ */
+ if (address == (nextpage_addr - psize) && cpa->numpages == numpages) {
+ /*
+ * The address is aligned and the number of pages
+ * covers the full page.
+ */
+ 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;
+ }
+
+out_unlock:
+ spin_unlock_irqrestore(&pgd_lock, flags);
+ return res;
+}
+
static int split_large_page(pte_t *kpte, unsigned long address)
{
- pgprot_t ref_prot = pte_pgprot(pte_clrhuge(*kpte));
+ pgprot_t ref_prot;
gfp_t gfp_flags = GFP_KERNEL;
unsigned long flags, addr, pfn;
pte_t *pbase, *tmp;
unsigned int i, level;
#ifdef CONFIG_DEBUG_PAGEALLOC
- gfp_flags = __GFP_HIGH | __GFP_NOFAIL | __GFP_NOWARN;
gfp_flags = GFP_ATOMIC | __GFP_NOWARN;
#endif
base = alloc_pages(gfp_flags, 0);
* 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 & LARGE_PAGE_MASK;
+ 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));
/*
* Get the target pfn from the original entry:
set_pte(&pbase[i], pfn_pte(pfn, ref_prot));
/*
- * Install the new, split up pagetable. Important detail here:
+ * Install the new, split up pagetable. Important details here:
*
* On Intel the NX bit of all levels must be cleared to make a
* page executable. See section 4.13.2 of Intel 64 and IA-32
* Architectures Software Developer's Manual).
+ *
+ * Mark the entry present. The current mapping might be
+ * set to not present, which we preserved above.
*/
ref_prot = pte_pgprot(pte_mkexec(pte_clrhuge(*kpte)));
+ pgprot_val(ref_prot) |= _PAGE_PRESENT;
__set_pmd_pte(kpte, address, mk_pte(base, ref_prot));
base = NULL;
return 0;
}
-static int
-__change_page_attr(unsigned long address, pgprot_t mask_set, pgprot_t mask_clr)
+static int __change_page_attr(unsigned long address, struct cpa_data *cpa)
{
struct page *kpte_page;
- int level, err = 0;
+ int level, res;
pte_t *kpte;
repeat:
pgprot_t new_prot = pte_pgprot(old_pte);
if(!pte_val(old_pte)) {
- WARN_ON_ONCE(1);
+ printk(KERN_WARNING "CPA: called for zero pte. "
+ "vaddr = %lx cpa->vaddr = %lx\n", address,
+ cpa->vaddr);
+ WARN_ON(1);
return -EINVAL;
}
- pgprot_val(new_prot) &= ~pgprot_val(mask_clr);
- pgprot_val(new_prot) |= pgprot_val(mask_set);
+ 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);
* not the memory it points to
*/
new_pte = pfn_pte(pte_pfn(old_pte), canon_pgprot(new_prot));
- set_pte_atomic(kpte, new_pte);
- } else {
- err = split_large_page(kpte, address);
- if (!err)
- goto repeat;
+
+ /*
+ * Do we really change anything ?
+ */
+ if (pte_val(old_pte) != pte_val(new_pte)) {
+ set_pte_atomic(kpte, new_pte);
+ cpa->flushtlb = 1;
+ }
+ cpa->numpages = 1;
+ return 0;
}
- return err;
+
+ /*
+ * 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;
+
+ /*
+ * 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;
+
+ /*
+ * We have to split the large page:
+ */
+ res = split_large_page(kpte, address);
+ if (res)
+ return res;
+ cpa->flushtlb = 1;
+ goto repeat;
}
/**
* Modules and drivers should use the set_memory_* APIs instead.
*/
-
-static int
-change_page_attr_addr(unsigned long address, pgprot_t mask_set,
- pgprot_t mask_clr)
+static int change_page_attr_addr(struct cpa_data *cpa)
{
int err;
+ unsigned long address = cpa->vaddr;
#ifdef CONFIG_X86_64
unsigned long phys_addr = __pa(address);
address = (unsigned long) __va(phys_addr);
#endif
- err = __change_page_attr(address, mask_set, mask_clr);
+ err = __change_page_attr(address, cpa);
if (err)
return err;
* everything between 0 and KERNEL_TEXT_SIZE, so do
* not propagate lookup failures back to users:
*/
- __change_page_attr(address, mask_set, mask_clr);
+ __change_page_attr(address, cpa);
}
#endif
return err;
}
-static int __change_page_attr_set_clr(unsigned long addr, int numpages,
- pgprot_t mask_set, pgprot_t mask_clr)
+static int __change_page_attr_set_clr(struct cpa_data *cpa)
{
- unsigned int i;
- int ret;
+ int ret, numpages = cpa->numpages;
- for (i = 0; i < numpages ; i++, addr += PAGE_SIZE) {
- ret = change_page_attr_addr(addr, mask_set, mask_clr);
+ while (numpages) {
+ /*
+ * Store the remaining nr of pages for the large page
+ * preservation check.
+ */
+ cpa->numpages = numpages;
+ ret = change_page_attr_addr(cpa);
if (ret)
return ret;
- }
+ /*
+ * Adjust the number of pages with the result of the
+ * CPA operation. Either a large page has been
+ * preserved or a single page update happened.
+ */
+ BUG_ON(cpa->numpages > numpages);
+ numpages -= cpa->numpages;
+ cpa->vaddr += cpa->numpages * PAGE_SIZE;
+ }
return 0;
}
+static inline int cache_attr(pgprot_t attr)
+{
+ return pgprot_val(attr) &
+ (_PAGE_PAT | _PAGE_PAT_LARGE | _PAGE_PWT | _PAGE_PCD);
+}
+
static int change_page_attr_set_clr(unsigned long addr, int numpages,
pgprot_t mask_set, pgprot_t mask_clr)
{
- int ret;
+ struct cpa_data cpa;
+ int ret, cache;
/*
* Check, if we are requested to change a not supported
if (!pgprot_val(mask_set) && !pgprot_val(mask_clr))
return 0;
- ret = __change_page_attr_set_clr(addr, numpages, mask_set, mask_clr);
+ 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);
+
+ /*
+ * Check whether we really changed something:
+ */
+ if (!cpa.flushtlb)
+ return ret;
+
+ /*
+ * No need to flush, when we did not set any of the caching
+ * attributes:
+ */
+ cache = cache_attr(mask_set);
/*
* On success we use clflush, when the CPU supports it to
* wbindv):
*/
if (!ret && cpu_has_clflush)
- cpa_flush_range(addr, numpages);
+ cpa_flush_range(addr, numpages, cache);
else
- cpa_flush_all();
+ cpa_flush_all(cache);
return ret;
}
return set_memory_rw(addr, numpages);
}
-
-#if defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_CPA_DEBUG)
-static inline int __change_page_attr_set(unsigned long addr, int numpages,
- pgprot_t mask)
-{
- return __change_page_attr_set_clr(addr, numpages, mask, __pgprot(0));
-}
-
-static inline int __change_page_attr_clear(unsigned long addr, int numpages,
- pgprot_t mask)
-{
- return __change_page_attr_set_clr(addr, numpages, __pgprot(0), mask);
-}
-#endif
-
#ifdef CONFIG_DEBUG_PAGEALLOC
static int __set_pages_p(struct page *page, int numpages)
{
- unsigned long addr = (unsigned long)page_address(page);
+ struct cpa_data cpa = { .vaddr = (unsigned long) page_address(page),
+ .numpages = numpages,
+ .mask_set = __pgprot(_PAGE_PRESENT | _PAGE_RW),
+ .mask_clr = __pgprot(0)};
- return __change_page_attr_set(addr, numpages,
- __pgprot(_PAGE_PRESENT | _PAGE_RW));
+ return __change_page_attr_set_clr(&cpa);
}
static int __set_pages_np(struct page *page, int numpages)
{
- unsigned long addr = (unsigned long)page_address(page);
+ struct cpa_data cpa = { .vaddr = (unsigned long) page_address(page),
+ .numpages = numpages,
+ .mask_set = __pgprot(0),
+ .mask_clr = __pgprot(_PAGE_PRESENT | _PAGE_RW)};
- return __change_page_attr_clear(addr, numpages,
- __pgprot(_PAGE_PRESENT));
+ return __change_page_attr_set_clr(&cpa);
}
void kernel_map_pages(struct page *page, int numpages, int enable)
projects / linux-2.6 / blobdiff