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-rw-r--r--include/linux/highmem.h489
1 files changed, 320 insertions, 169 deletions
diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index ea5cdbd8c2c3..e9912da5441b 100644
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -5,186 +5,229 @@
#include <linux/fs.h>
#include <linux/kernel.h>
#include <linux/bug.h>
+#include <linux/cacheflush.h>
+#include <linux/kmsan.h>
#include <linux/mm.h>
#include <linux/uaccess.h>
#include <linux/hardirq.h>
-#include <asm/cacheflush.h>
+#include "highmem-internal.h"
-#ifndef ARCH_HAS_FLUSH_ANON_PAGE
-static inline void flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
-{
-}
-#endif
-
-#ifndef ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
-static inline void flush_kernel_dcache_page(struct page *page)
-{
-}
-static inline void flush_kernel_vmap_range(void *vaddr, int size)
-{
-}
-static inline void invalidate_kernel_vmap_range(void *vaddr, int size)
-{
-}
-#endif
-
-#include <asm/kmap_types.h>
-
-#ifdef CONFIG_HIGHMEM
-#include <asm/highmem.h>
-
-/* declarations for linux/mm/highmem.c */
-unsigned int nr_free_highpages(void);
-extern atomic_long_t _totalhigh_pages;
-static inline unsigned long totalhigh_pages(void)
-{
- return (unsigned long)atomic_long_read(&_totalhigh_pages);
-}
-
-static inline void totalhigh_pages_inc(void)
-{
- atomic_long_inc(&_totalhigh_pages);
-}
-
-static inline void totalhigh_pages_dec(void)
-{
- atomic_long_dec(&_totalhigh_pages);
-}
-
-static inline void totalhigh_pages_add(long count)
-{
- atomic_long_add(count, &_totalhigh_pages);
-}
-
-static inline void totalhigh_pages_set(long val)
-{
- atomic_long_set(&_totalhigh_pages, val);
-}
-
-void kmap_flush_unused(void);
+/**
+ * kmap - Map a page for long term usage
+ * @page: Pointer to the page to be mapped
+ *
+ * Returns: The virtual address of the mapping
+ *
+ * Can only be invoked from preemptible task context because on 32bit
+ * systems with CONFIG_HIGHMEM enabled this function might sleep.
+ *
+ * For systems with CONFIG_HIGHMEM=n and for pages in the low memory area
+ * this returns the virtual address of the direct kernel mapping.
+ *
+ * The returned virtual address is globally visible and valid up to the
+ * point where it is unmapped via kunmap(). The pointer can be handed to
+ * other contexts.
+ *
+ * For highmem pages on 32bit systems this can be slow as the mapping space
+ * is limited and protected by a global lock. In case that there is no
+ * mapping slot available the function blocks until a slot is released via
+ * kunmap().
+ */
+static inline void *kmap(struct page *page);
-struct page *kmap_to_page(void *addr);
+/**
+ * kunmap - Unmap the virtual address mapped by kmap()
+ * @page: Pointer to the page which was mapped by kmap()
+ *
+ * Counterpart to kmap(). A NOOP for CONFIG_HIGHMEM=n and for mappings of
+ * pages in the low memory area.
+ */
+static inline void kunmap(struct page *page);
-#else /* CONFIG_HIGHMEM */
+/**
+ * kmap_to_page - Get the page for a kmap'ed address
+ * @addr: The address to look up
+ *
+ * Returns: The page which is mapped to @addr.
+ */
+static inline struct page *kmap_to_page(void *addr);
-static inline unsigned int nr_free_highpages(void) { return 0; }
+/**
+ * kmap_flush_unused - Flush all unused kmap mappings in order to
+ * remove stray mappings
+ */
+static inline void kmap_flush_unused(void);
-static inline struct page *kmap_to_page(void *addr)
-{
- return virt_to_page(addr);
-}
+/**
+ * kmap_local_page - Map a page for temporary usage
+ * @page: Pointer to the page to be mapped
+ *
+ * Returns: The virtual address of the mapping
+ *
+ * Can be invoked from any context, including interrupts.
+ *
+ * Requires careful handling when nesting multiple mappings because the map
+ * management is stack based. The unmap has to be in the reverse order of
+ * the map operation:
+ *
+ * addr1 = kmap_local_page(page1);
+ * addr2 = kmap_local_page(page2);
+ * ...
+ * kunmap_local(addr2);
+ * kunmap_local(addr1);
+ *
+ * Unmapping addr1 before addr2 is invalid and causes malfunction.
+ *
+ * Contrary to kmap() mappings the mapping is only valid in the context of
+ * the caller and cannot be handed to other contexts.
+ *
+ * On CONFIG_HIGHMEM=n kernels and for low memory pages this returns the
+ * virtual address of the direct mapping. Only real highmem pages are
+ * temporarily mapped.
+ *
+ * While it is significantly faster than kmap() for the higmem case it
+ * comes with restrictions about the pointer validity.
+ *
+ * On HIGHMEM enabled systems mapping a highmem page has the side effect of
+ * disabling migration in order to keep the virtual address stable across
+ * preemption. No caller of kmap_local_page() can rely on this side effect.
+ */
+static inline void *kmap_local_page(struct page *page);
-static inline unsigned long totalhigh_pages(void) { return 0UL; }
+/**
+ * kmap_local_folio - Map a page in this folio for temporary usage
+ * @folio: The folio containing the page.
+ * @offset: The byte offset within the folio which identifies the page.
+ *
+ * Requires careful handling when nesting multiple mappings because the map
+ * management is stack based. The unmap has to be in the reverse order of
+ * the map operation::
+ *
+ * addr1 = kmap_local_folio(folio1, offset1);
+ * addr2 = kmap_local_folio(folio2, offset2);
+ * ...
+ * kunmap_local(addr2);
+ * kunmap_local(addr1);
+ *
+ * Unmapping addr1 before addr2 is invalid and causes malfunction.
+ *
+ * Contrary to kmap() mappings the mapping is only valid in the context of
+ * the caller and cannot be handed to other contexts.
+ *
+ * On CONFIG_HIGHMEM=n kernels and for low memory pages this returns the
+ * virtual address of the direct mapping. Only real highmem pages are
+ * temporarily mapped.
+ *
+ * While it is significantly faster than kmap() for the higmem case it
+ * comes with restrictions about the pointer validity. Only use when really
+ * necessary.
+ *
+ * On HIGHMEM enabled systems mapping a highmem page has the side effect of
+ * disabling migration in order to keep the virtual address stable across
+ * preemption. No caller of kmap_local_folio() can rely on this side effect.
+ *
+ * Context: Can be invoked from any context.
+ * Return: The virtual address of @offset.
+ */
+static inline void *kmap_local_folio(struct folio *folio, size_t offset);
-#ifndef ARCH_HAS_KMAP
-static inline void *kmap(struct page *page)
-{
- might_sleep();
- return page_address(page);
-}
+/**
+ * kmap_atomic - Atomically map a page for temporary usage - Deprecated!
+ * @page: Pointer to the page to be mapped
+ *
+ * Returns: The virtual address of the mapping
+ *
+ * In fact a wrapper around kmap_local_page() which also disables pagefaults
+ * and, depending on PREEMPT_RT configuration, also CPU migration and
+ * preemption. Therefore users should not count on the latter two side effects.
+ *
+ * Mappings should always be released by kunmap_atomic().
+ *
+ * Do not use in new code. Use kmap_local_page() instead.
+ *
+ * It is used in atomic context when code wants to access the contents of a
+ * page that might be allocated from high memory (see __GFP_HIGHMEM), for
+ * example a page in the pagecache. The API has two functions, and they
+ * can be used in a manner similar to the following::
+ *
+ * // Find the page of interest.
+ * struct page *page = find_get_page(mapping, offset);
+ *
+ * // Gain access to the contents of that page.
+ * void *vaddr = kmap_atomic(page);
+ *
+ * // Do something to the contents of that page.
+ * memset(vaddr, 0, PAGE_SIZE);
+ *
+ * // Unmap that page.
+ * kunmap_atomic(vaddr);
+ *
+ * Note that the kunmap_atomic() call takes the result of the kmap_atomic()
+ * call, not the argument.
+ *
+ * If you need to map two pages because you want to copy from one page to
+ * another you need to keep the kmap_atomic calls strictly nested, like:
+ *
+ * vaddr1 = kmap_atomic(page1);
+ * vaddr2 = kmap_atomic(page2);
+ *
+ * memcpy(vaddr1, vaddr2, PAGE_SIZE);
+ *
+ * kunmap_atomic(vaddr2);
+ * kunmap_atomic(vaddr1);
+ */
+static inline void *kmap_atomic(struct page *page);
-static inline void kunmap(struct page *page)
-{
-}
+/* Highmem related interfaces for management code */
+static inline unsigned int nr_free_highpages(void);
+static inline unsigned long totalhigh_pages(void);
-static inline void *kmap_atomic(struct page *page)
-{
- preempt_disable();
- pagefault_disable();
- return page_address(page);
-}
-#define kmap_atomic_prot(page, prot) kmap_atomic(page)
-
-static inline void __kunmap_atomic(void *addr)
+#ifndef ARCH_HAS_FLUSH_ANON_PAGE
+static inline void flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
{
- pagefault_enable();
- preempt_enable();
}
-
-#define kmap_atomic_pfn(pfn) kmap_atomic(pfn_to_page(pfn))
-
-#define kmap_flush_unused() do {} while(0)
-#endif
-
-#endif /* CONFIG_HIGHMEM */
-
-#if defined(CONFIG_HIGHMEM) || defined(CONFIG_X86_32)
-
-DECLARE_PER_CPU(int, __kmap_atomic_idx);
-
-static inline int kmap_atomic_idx_push(void)
-{
- int idx = __this_cpu_inc_return(__kmap_atomic_idx) - 1;
-
-#ifdef CONFIG_DEBUG_HIGHMEM
- WARN_ON_ONCE(in_irq() && !irqs_disabled());
- BUG_ON(idx >= KM_TYPE_NR);
#endif
- return idx;
-}
-static inline int kmap_atomic_idx(void)
+#ifndef ARCH_IMPLEMENTS_FLUSH_KERNEL_VMAP_RANGE
+static inline void flush_kernel_vmap_range(void *vaddr, int size)
{
- return __this_cpu_read(__kmap_atomic_idx) - 1;
}
-
-static inline void kmap_atomic_idx_pop(void)
+static inline void invalidate_kernel_vmap_range(void *vaddr, int size)
{
-#ifdef CONFIG_DEBUG_HIGHMEM
- int idx = __this_cpu_dec_return(__kmap_atomic_idx);
-
- BUG_ON(idx < 0);
-#else
- __this_cpu_dec(__kmap_atomic_idx);
-#endif
}
-
#endif
-/*
- * Prevent people trying to call kunmap_atomic() as if it were kunmap()
- * kunmap_atomic() should get the return value of kmap_atomic, not the page.
- */
-#define kunmap_atomic(addr) \
-do { \
- BUILD_BUG_ON(__same_type((addr), struct page *)); \
- __kunmap_atomic(addr); \
-} while (0)
-
-
/* when CONFIG_HIGHMEM is not set these will be plain clear/copy_page */
#ifndef clear_user_highpage
static inline void clear_user_highpage(struct page *page, unsigned long vaddr)
{
- void *addr = kmap_atomic(page);
+ void *addr = kmap_local_page(page);
clear_user_page(addr, vaddr, page);
- kunmap_atomic(addr);
+ kunmap_local(addr);
}
#endif
-#ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE
+#ifndef __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE_MOVABLE
/**
- * __alloc_zeroed_user_highpage - Allocate a zeroed HIGHMEM page for a VMA with caller-specified movable GFP flags
- * @movableflags: The GFP flags related to the pages future ability to move like __GFP_MOVABLE
+ * alloc_zeroed_user_highpage_movable - Allocate a zeroed HIGHMEM page for a VMA that the caller knows can move
* @vma: The VMA the page is to be allocated for
* @vaddr: The virtual address the page will be inserted into
*
- * This function will allocate a page for a VMA but the caller is expected
- * to specify via movableflags whether the page will be movable in the
- * future or not
+ * Returns: The allocated and zeroed HIGHMEM page
+ *
+ * This function will allocate a page for a VMA that the caller knows will
+ * be able to migrate in the future using move_pages() or reclaimed
*
* An architecture may override this function by defining
- * __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE and providing their own
+ * __HAVE_ARCH_ALLOC_ZEROED_USER_HIGHPAGE_MOVABLE and providing their own
* implementation.
*/
static inline struct page *
-__alloc_zeroed_user_highpage(gfp_t movableflags,
- struct vm_area_struct *vma,
- unsigned long vaddr)
+alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma,
+ unsigned long vaddr)
{
- struct page *page = alloc_page_vma(GFP_HIGHUSER | movableflags,
- vma, vaddr);
+ struct page *page = alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, vaddr);
if (page)
clear_user_highpage(page, vaddr);
@@ -193,35 +236,47 @@ __alloc_zeroed_user_highpage(gfp_t movableflags,
}
#endif
-/**
- * alloc_zeroed_user_highpage_movable - Allocate a zeroed HIGHMEM page for a VMA that the caller knows can move
- * @vma: The VMA the page is to be allocated for
- * @vaddr: The virtual address the page will be inserted into
- *
- * This function will allocate a page for a VMA that the caller knows will
- * be able to migrate in the future using move_pages() or reclaimed
- */
-static inline struct page *
-alloc_zeroed_user_highpage_movable(struct vm_area_struct *vma,
- unsigned long vaddr)
+static inline void clear_highpage(struct page *page)
{
- return __alloc_zeroed_user_highpage(__GFP_MOVABLE, vma, vaddr);
+ void *kaddr = kmap_local_page(page);
+ clear_page(kaddr);
+ kunmap_local(kaddr);
}
-static inline void clear_highpage(struct page *page)
+static inline void clear_highpage_kasan_tagged(struct page *page)
{
- void *kaddr = kmap_atomic(page);
- clear_page(kaddr);
- kunmap_atomic(kaddr);
+ u8 tag;
+
+ tag = page_kasan_tag(page);
+ page_kasan_tag_reset(page);
+ clear_highpage(page);
+ page_kasan_tag_set(page, tag);
}
+#ifndef __HAVE_ARCH_TAG_CLEAR_HIGHPAGE
+
+static inline void tag_clear_highpage(struct page *page)
+{
+}
+
+#endif
+
+/*
+ * If we pass in a base or tail page, we can zero up to PAGE_SIZE.
+ * If we pass in a head page, we can zero up to the size of the compound page.
+ */
+#ifdef CONFIG_HIGHMEM
+void zero_user_segments(struct page *page, unsigned start1, unsigned end1,
+ unsigned start2, unsigned end2);
+#else
static inline void zero_user_segments(struct page *page,
- unsigned start1, unsigned end1,
- unsigned start2, unsigned end2)
+ unsigned start1, unsigned end1,
+ unsigned start2, unsigned end2)
{
- void *kaddr = kmap_atomic(page);
+ void *kaddr = kmap_local_page(page);
+ unsigned int i;
- BUG_ON(end1 > PAGE_SIZE || end2 > PAGE_SIZE);
+ BUG_ON(end1 > page_size(page) || end2 > page_size(page));
if (end1 > start1)
memset(kaddr + start1, 0, end1 - start1);
@@ -229,9 +284,11 @@ static inline void zero_user_segments(struct page *page,
if (end2 > start2)
memset(kaddr + start2, 0, end2 - start2);
- kunmap_atomic(kaddr);
- flush_dcache_page(page);
+ kunmap_local(kaddr);
+ for (i = 0; i < compound_nr(page); i++)
+ flush_dcache_page(page + i);
}
+#endif
static inline void zero_user_segment(struct page *page,
unsigned start, unsigned end)
@@ -252,11 +309,12 @@ static inline void copy_user_highpage(struct page *to, struct page *from,
{
char *vfrom, *vto;
- vfrom = kmap_atomic(from);
- vto = kmap_atomic(to);
+ vfrom = kmap_local_page(from);
+ vto = kmap_local_page(to);
copy_user_page(vto, vfrom, vaddr, to);
- kunmap_atomic(vto);
- kunmap_atomic(vfrom);
+ kmsan_unpoison_memory(page_address(to), PAGE_SIZE);
+ kunmap_local(vto);
+ kunmap_local(vfrom);
}
#endif
@@ -267,13 +325,106 @@ static inline void copy_highpage(struct page *to, struct page *from)
{
char *vfrom, *vto;
- vfrom = kmap_atomic(from);
- vto = kmap_atomic(to);
+ vfrom = kmap_local_page(from);
+ vto = kmap_local_page(to);
copy_page(vto, vfrom);
- kunmap_atomic(vto);
- kunmap_atomic(vfrom);
+ kmsan_copy_page_meta(to, from);
+ kunmap_local(vto);
+ kunmap_local(vfrom);
}
#endif
+static inline void memcpy_page(struct page *dst_page, size_t dst_off,
+ struct page *src_page, size_t src_off,
+ size_t len)
+{
+ char *dst = kmap_local_page(dst_page);
+ char *src = kmap_local_page(src_page);
+
+ VM_BUG_ON(dst_off + len > PAGE_SIZE || src_off + len > PAGE_SIZE);
+ memcpy(dst + dst_off, src + src_off, len);
+ kunmap_local(src);
+ kunmap_local(dst);
+}
+
+static inline void memset_page(struct page *page, size_t offset, int val,
+ size_t len)
+{
+ char *addr = kmap_local_page(page);
+
+ VM_BUG_ON(offset + len > PAGE_SIZE);
+ memset(addr + offset, val, len);
+ kunmap_local(addr);
+}
+
+static inline void memcpy_from_page(char *to, struct page *page,
+ size_t offset, size_t len)
+{
+ char *from = kmap_local_page(page);
+
+ VM_BUG_ON(offset + len > PAGE_SIZE);
+ memcpy(to, from + offset, len);
+ kunmap_local(from);
+}
+
+static inline void memcpy_to_page(struct page *page, size_t offset,
+ const char *from, size_t len)
+{
+ char *to = kmap_local_page(page);
+
+ VM_BUG_ON(offset + len > PAGE_SIZE);
+ memcpy(to + offset, from, len);
+ flush_dcache_page(page);
+ kunmap_local(to);
+}
+
+static inline void memzero_page(struct page *page, size_t offset, size_t len)
+{
+ char *addr = kmap_local_page(page);
+
+ VM_BUG_ON(offset + len > PAGE_SIZE);
+ memset(addr + offset, 0, len);
+ flush_dcache_page(page);
+ kunmap_local(addr);
+}
+
+/**
+ * folio_zero_segments() - Zero two byte ranges in a folio.
+ * @folio: The folio to write to.
+ * @start1: The first byte to zero.
+ * @xend1: One more than the last byte in the first range.
+ * @start2: The first byte to zero in the second range.
+ * @xend2: One more than the last byte in the second range.
+ */
+static inline void folio_zero_segments(struct folio *folio,
+ size_t start1, size_t xend1, size_t start2, size_t xend2)
+{
+ zero_user_segments(&folio->page, start1, xend1, start2, xend2);
+}
+
+/**
+ * folio_zero_segment() - Zero a byte range in a folio.
+ * @folio: The folio to write to.
+ * @start: The first byte to zero.
+ * @xend: One more than the last byte to zero.
+ */
+static inline void folio_zero_segment(struct folio *folio,
+ size_t start, size_t xend)
+{
+ zero_user_segments(&folio->page, start, xend, 0, 0);
+}
+
+/**
+ * folio_zero_range() - Zero a byte range in a folio.
+ * @folio: The folio to write to.
+ * @start: The first byte to zero.
+ * @length: The number of bytes to zero.
+ */
+static inline void folio_zero_range(struct folio *folio,
+ size_t start, size_t length)
+{
+ zero_user_segments(&folio->page, start, start + length, 0, 0);
+}
+
#endif /* _LINUX_HIGHMEM_H */