1 files changed, 564 insertions, 0 deletions
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
new file mode 100644
index 00000000000..1cc6607eacb
--- /dev/null
+++ b/arch/x86/mm/pageattr.c
@@ -0,0 +1,564 @@
+/*
+ * Copyright 2002 Andi Kleen, SuSE Labs.
+ * Thanks to Ben LaHaise for precious feedback.
+ */
+#include <linux/highmem.h>
+#include <linux/bootmem.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+
+#include <asm/e820.h>
+#include <asm/processor.h>
+#include <asm/tlbflush.h>
+#include <asm/sections.h>
+#include <asm/uaccess.h>
+#include <asm/pgalloc.h>
+
+static inline int
+within(unsigned long addr, unsigned long start, unsigned long end)
+{
+	return addr >= start && addr < end;
+}
+
+/*
+ * Flushing functions
+ */
+
+/**
+ * clflush_cache_range - flush a cache range with clflush
+ * @addr:	virtual start address
+ * @size:	number of bytes to flush
+ *
+ * clflush is an unordered instruction which needs fencing with mfence
+ * to avoid ordering issues.
+ */
+void clflush_cache_range(void *vaddr, unsigned int size)
+{
+	void *vend = vaddr + size - 1;
+
+	mb();
+
+	for (; vaddr < vend; vaddr += boot_cpu_data.x86_clflush_size)
+		clflush(vaddr);
+	/*
+	 * Flush any possible final partial cacheline:
+	 */
+	clflush(vend);
+
+	mb();
+}
+
+static void __cpa_flush_all(void *arg)
+{
+	/*
+	 * Flush all to work around Errata in early athlons regarding
+	 * large page flushing.
+	 */
+	__flush_tlb_all();
+
+	if (boot_cpu_data.x86_model >= 4)
+		wbinvd();
+}
+
+static void cpa_flush_all(void)
+{
+	BUG_ON(irqs_disabled());
+
+	on_each_cpu(__cpa_flush_all, NULL, 1, 1);
+}
+
+static void __cpa_flush_range(void *arg)
+{
+	/*
+	 * We could optimize that further and do individual per page
+	 * tlb invalidates for a low number of pages. Caveat: we must
+	 * flush the high aliases on 64bit as well.
+	 */
+	__flush_tlb_all();
+}
+
+static void cpa_flush_range(unsigned long start, int numpages)
+{
+	unsigned int i, level;
+	unsigned long addr;
+
+	BUG_ON(irqs_disabled());
+	WARN_ON(PAGE_ALIGN(start) != start);
+
+	on_each_cpu(__cpa_flush_range, NULL, 1, 1);
+
+	/*
+	 * We only need to flush on one CPU,
+	 * clflush is a MESI-coherent instruction that
+	 * will cause all other CPUs to flush the same
+	 * cachelines:
+	 */
+	for (i = 0, addr = start; i < numpages; i++, addr += PAGE_SIZE) {
+		pte_t *pte = lookup_address(addr, &level);
+
+		/*
+		 * Only flush present addresses:
+		 */
+		if (pte && pte_present(*pte))
+			clflush_cache_range((void *) addr, PAGE_SIZE);
+	}
+}
+
+/*
+ * 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)
+{
+	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))
+		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
+	 */
+	if (within(address, (unsigned long)_text, (unsigned long)_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;
+#endif
+
+	prot = __pgprot(pgprot_val(prot) & ~pgprot_val(forbidden));
+
+	return prot;
+}
+
+pte_t *lookup_address(unsigned long address, int *level)
+{
+	pgd_t *pgd = pgd_offset_k(address);
+	pud_t *pud;
+	pmd_t *pmd;
+
+	*level = PG_LEVEL_NONE;
+
+	if (pgd_none(*pgd))
+		return NULL;
+	pud = pud_offset(pgd, address);
+	if (pud_none(*pud))
+		return NULL;
+	pmd = pmd_offset(pud, address);
+	if (pmd_none(*pmd))
+		return NULL;
+
+	*level = PG_LEVEL_2M;
+	if (pmd_large(*pmd))
+		return (pte_t *)pmd;
+
+	*level = PG_LEVEL_4K;
+	return pte_offset_kernel(pmd, address);
+}
+
+static void __set_pmd_pte(pte_t *kpte, unsigned long address, pte_t pte)
+{
+	/* change init_mm */
+	set_pte_atomic(kpte, pte);
+#ifdef CONFIG_X86_32
+	if (!SHARED_KERNEL_PMD) {
+		struct page *page;
+
+		list_for_each_entry(page, &pgd_list, lru) {
+			pgd_t *pgd;
+			pud_t *pud;
+			pmd_t *pmd;
+
+			pgd = (pgd_t *)page_address(page) + pgd_index(address);
+			pud = pud_offset(pgd, address);
+			pmd = pmd_offset(pud, address);
+			set_pte_atomic((pte_t *)pmd, pte);
+		}
+	}
+#endif
+}
+
+static int split_large_page(pte_t *kpte, unsigned long address)
+{
+	pgprot_t ref_prot = pte_pgprot(pte_clrhuge(*kpte));
+	gfp_t gfp_flags = GFP_KERNEL;
+	unsigned long flags;
+	unsigned long addr;
+	pte_t *pbase, *tmp;
+	struct page *base;
+	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);
+	if (!base)
+		return -ENOMEM;
+
+	spin_lock_irqsave(&pgd_lock, flags);
+	/*
+	 * 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);
+		goto out_unlock;
+	}
+
+	address = __pa(address);
+	addr = address & LARGE_PAGE_MASK;
+	pbase = (pte_t *)page_address(base);
+#ifdef CONFIG_X86_32
+	paravirt_alloc_pt(&init_mm, page_to_pfn(base));
+#endif
+
+	pgprot_val(ref_prot) &= ~_PAGE_NX;
+	for (i = 0; i < PTRS_PER_PTE; i++, addr += PAGE_SIZE)
+		set_pte(&pbase[i], pfn_pte(addr >> PAGE_SHIFT, ref_prot));
+
+	/*
+	 * Install the new, split up pagetable. Important detail 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).
+	 */
+	ref_prot = pte_pgprot(pte_mkexec(pte_clrhuge(*kpte)));
+	__set_pmd_pte(kpte, address, mk_pte(base, ref_prot));
+	base = NULL;
+
+out_unlock:
+	spin_unlock_irqrestore(&pgd_lock, flags);
+
+	if (base)
+		__free_pages(base, 0);
+
+	return 0;
+}
+
+static int
+__change_page_attr(unsigned long address, unsigned long pfn,
+		   pgprot_t mask_set, pgprot_t mask_clr)
+{
+	struct page *kpte_page;
+	int level, err = 0;
+	pte_t *kpte;
+
+#ifdef CONFIG_X86_32
+	BUG_ON(pfn > max_low_pfn);
+#endif
+
+repeat:
+	kpte = lookup_address(address, &level);
+	if (!kpte)
+		return -EINVAL;
+
+	kpte_page = virt_to_page(kpte);
+	BUG_ON(PageLRU(kpte_page));
+	BUG_ON(PageCompound(kpte_page));
+
+	if (level == PG_LEVEL_4K) {
+		pgprot_t new_prot = pte_pgprot(*kpte);
+		pte_t new_pte, old_pte = *kpte;
+
+		pgprot_val(new_prot) &= ~pgprot_val(mask_clr);
+		pgprot_val(new_prot) |= pgprot_val(mask_set);
+
+		new_prot = static_protections(new_prot, address);
+
+		new_pte = pfn_pte(pfn, canon_pgprot(new_prot));
+		BUG_ON(pte_pfn(new_pte) != pte_pfn(old_pte));
+
+		set_pte_atomic(kpte, new_pte);
+	} else {
+		err = split_large_page(kpte, address);
+		if (!err)
+			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.
+ */
+
+#define HIGH_MAP_START	__START_KERNEL_map
+#define HIGH_MAP_END	(__START_KERNEL_map + KERNEL_TEXT_SIZE)
+
+static int
+change_page_attr_addr(unsigned long address, pgprot_t mask_set,
+		      pgprot_t mask_clr)
+{
+	unsigned long phys_addr = __pa(address);
+	unsigned long pfn = phys_addr >> PAGE_SHIFT;
+	int err;
+
+#ifdef CONFIG_X86_64
+	/*
+	 * 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:
+	 */
+	if (within(address, HIGH_MAP_START, HIGH_MAP_END))
+		address = (unsigned long) __va(phys_addr);
+#endif
+
+	err = __change_page_attr(address, pfn, mask_set, mask_clr);
+	if (err)
+		return err;
+
+#ifdef CONFIG_X86_64
+	/*
+	 * 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.
+		 */
+		address = phys_addr + HIGH_MAP_START - phys_base;
+		/* Make sure the kernel mappings stay executable */
+		pgprot_val(mask_clr) |= _PAGE_NX;
+
+		/*
+		 * 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, pfn, mask_set, mask_clr);
+	}
+#endif
+	return err;
+}
+
+static int __change_page_attr_set_clr(unsigned long addr, int numpages,
+				      pgprot_t mask_set, pgprot_t mask_clr)
+{
+	unsigned int i;
+	int ret;
+
+	for (i = 0; i < numpages ; i++, addr += PAGE_SIZE) {
+		ret = change_page_attr_addr(addr, mask_set, mask_clr);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static int change_page_attr_set_clr(unsigned long addr, int numpages,
+				    pgprot_t mask_set, pgprot_t mask_clr)
+{
+	int ret = __change_page_attr_set_clr(addr, numpages, mask_set,
+					     mask_clr);
+
+	/*
+	 * On success we use clflush, when the CPU supports it to
+	 * avoid the wbindv. If the CPU does not support it and in the
+	 * error case we fall back to cpa_flush_all (which uses
+	 * wbindv):
+	 */
+	if (!ret && cpu_has_clflush)
+		cpa_flush_range(addr, numpages);
+	else
+		cpa_flush_all();
+
+	return ret;
+}
+
+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);
+
+}
+
+int set_memory_uc(unsigned long addr, int numpages)
+{
+	return change_page_attr_set(addr, numpages,
+				    __pgprot(_PAGE_PCD | _PAGE_PWT));
+}
+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));
+}
+EXPORT_SYMBOL(set_memory_wb);
+
+int set_memory_x(unsigned long addr, int numpages)
+{
+	return change_page_attr_clear(addr, numpages, __pgprot(_PAGE_NX));
+}
+EXPORT_SYMBOL(set_memory_x);
+
+int set_memory_nx(unsigned long addr, int numpages)
+{
+	return change_page_attr_set(addr, numpages, __pgprot(_PAGE_NX));
+}
+EXPORT_SYMBOL(set_memory_nx);
+
+int set_memory_ro(unsigned long addr, int numpages)
+{
+	return change_page_attr_clear(addr, numpages, __pgprot(_PAGE_RW));
+}
+
+int set_memory_rw(unsigned long addr, int numpages)
+{
+	return change_page_attr_set(addr, numpages, __pgprot(_PAGE_RW));
+}
+
+int set_memory_np(unsigned long addr, int numpages)
+{
+	return change_page_attr_clear(addr, numpages, __pgprot(_PAGE_PRESENT));
+}
+
+int set_pages_uc(struct page *page, int numpages)
+{
+	unsigned long addr = (unsigned long)page_address(page);
+
+	return set_memory_uc(addr, numpages);
+}
+EXPORT_SYMBOL(set_pages_uc);
+
+int set_pages_wb(struct page *page, int numpages)
+{
+	unsigned long addr = (unsigned long)page_address(page);
+
+	return set_memory_wb(addr, numpages);
+}
+EXPORT_SYMBOL(set_pages_wb);
+
+int set_pages_x(struct page *page, int numpages)
+{
+	unsigned long addr = (unsigned long)page_address(page);
+
+	return set_memory_x(addr, numpages);
+}
+EXPORT_SYMBOL(set_pages_x);
+
+int set_pages_nx(struct page *page, int numpages)
+{
+	unsigned long addr = (unsigned long)page_address(page);
+
+	return set_memory_nx(addr, numpages);
+}
+EXPORT_SYMBOL(set_pages_nx);
+
+int set_pages_ro(struct page *page, int numpages)
+{
+	unsigned long addr = (unsigned long)page_address(page);
+
+	return set_memory_ro(addr, numpages);
+}
+
+int set_pages_rw(struct page *page, int numpages)
+{
+	unsigned long addr = (unsigned long)page_address(page);
+
+	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);
+
+	return __change_page_attr_set(addr, numpages,
+				      __pgprot(_PAGE_PRESENT | _PAGE_RW));
+}
+
+static int __set_pages_np(struct page *page, int numpages)
+{
+	unsigned long addr = (unsigned long)page_address(page);
+
+	return __change_page_attr_clear(addr, numpages,
+					__pgprot(_PAGE_PRESENT));
+}
+
+void kernel_map_pages(struct page *page, int numpages, int enable)
+{
+	if (PageHighMem(page))
+		return;
+	if (!enable) {
+		debug_check_no_locks_freed(page_address(page),
+					   numpages * PAGE_SIZE);
+	}
+
+	/*
+	 * If page allocator is not up yet then do not call c_p_a():
+	 */
+	if (!debug_pagealloc_enabled)
+		return;
+
+	/*
+	 * The return value is ignored - the calls cannot fail,
+	 * large pages are disabled at boot time:
+	 */
+	if (enable)
+		__set_pages_p(page, numpages);
+	else
+		__set_pages_np(page, numpages);
+
+	/*
+	 * We should perform an IPI and flush all tlbs,
+	 * but that can deadlock->flush only current cpu:
+	 */
+	__flush_tlb_all();
+}
+#endif
+
+/*
+ * The testcases use internal knowledge of the implementation that shouldn't
+ * be exposed to the rest of the kernel. Include these directly here.
+ */
+#ifdef CONFIG_CPA_DEBUG
+#include "pageattr-test.c"
+#endif