#include <linux/swap.h>
#include <asm/pgalloc.h>
#include <asm/tlbflush.h>
+#include <asm/cacheflush.h>
/*
* Blindly accessing user memory from NMI context can be dangerous
#ifdef CONFIG_MMU
+/*
+ * Generic MMU-gather implementation.
+ *
+ * The mmu_gather data structure is used by the mm code to implement the
+ * correct and efficient ordering of freeing pages and TLB invalidations.
+ *
+ * This correct ordering is:
+ *
+ * 1) unhook page
+ * 2) TLB invalidate page
+ * 3) free page
+ *
+ * That is, we must never free a page before we have ensured there are no live
+ * translations left to it. Otherwise it might be possible to observe (or
+ * worse, change) the page content after it has been reused.
+ *
+ * The mmu_gather API consists of:
+ *
+ * - tlb_gather_mmu() / tlb_finish_mmu(); start and finish a mmu_gather
+ *
+ * Finish in particular will issue a (final) TLB invalidate and free
+ * all (remaining) queued pages.
+ *
+ * - tlb_start_vma() / tlb_end_vma(); marks the start / end of a VMA
+ *
+ * Defaults to flushing at tlb_end_vma() to reset the range; helps when
+ * there's large holes between the VMAs.
+ *
+ * - tlb_remove_page() / __tlb_remove_page()
+ * - tlb_remove_page_size() / __tlb_remove_page_size()
+ *
+ * __tlb_remove_page_size() is the basic primitive that queues a page for
+ * freeing. __tlb_remove_page() assumes PAGE_SIZE. Both will return a
+ * boolean indicating if the queue is (now) full and a call to
+ * tlb_flush_mmu() is required.
+ *
+ * tlb_remove_page() and tlb_remove_page_size() imply the call to
+ * tlb_flush_mmu() when required and has no return value.
+ *
+ * - tlb_change_page_size()
+ *
+ * call before __tlb_remove_page*() to set the current page-size; implies a
+ * possible tlb_flush_mmu() call.
+ *
+ * - tlb_flush_mmu() / tlb_flush_mmu_tlbonly()
+ *
+ * tlb_flush_mmu_tlbonly() - does the TLB invalidate (and resets
+ * related state, like the range)
+ *
+ * tlb_flush_mmu() - in addition to the above TLB invalidate, also frees
+ * whatever pages are still batched.
+ *
+ * - mmu_gather::fullmm
+ *
+ * A flag set by tlb_gather_mmu() to indicate we're going to free
+ * the entire mm; this allows a number of optimizations.
+ *
+ * - We can ignore tlb_{start,end}_vma(); because we don't
+ * care about ranges. Everything will be shot down.
+ *
+ * - (RISC) architectures that use ASIDs can cycle to a new ASID
+ * and delay the invalidation until ASID space runs out.
+ *
+ * - mmu_gather::need_flush_all
+ *
+ * A flag that can be set by the arch code if it wants to force
+ * flush the entire TLB irrespective of the range. For instance
+ * x86-PAE needs this when changing top-level entries.
+ *
+ * And allows the architecture to provide and implement tlb_flush():
+ *
+ * tlb_flush() may, in addition to the above mentioned mmu_gather fields, make
+ * use of:
+ *
+ * - mmu_gather::start / mmu_gather::end
+ *
+ * which provides the range that needs to be flushed to cover the pages to
+ * be freed.
+ *
+ * - mmu_gather::freed_tables
+ *
+ * set when we freed page table pages
+ *
+ * - tlb_get_unmap_shift() / tlb_get_unmap_size()
+ *
+ * returns the smallest TLB entry size unmapped in this range.
+ *
+ * If an architecture does not provide tlb_flush() a default implementation
+ * based on flush_tlb_range() will be used, unless MMU_GATHER_NO_RANGE is
+ * specified, in which case we'll default to flush_tlb_mm().
+ *
+ * Additionally there are a few opt-in features:
+ *
+ * HAVE_MMU_GATHER_PAGE_SIZE
+ *
+ * This ensures we call tlb_flush() every time tlb_change_page_size() actually
+ * changes the size and provides mmu_gather::page_size to tlb_flush().
+ *
+ * HAVE_RCU_TABLE_FREE
+ *
+ * This provides tlb_remove_table(), to be used instead of tlb_remove_page()
+ * for page directores (__p*_free_tlb()). This provides separate freeing of
+ * the page-table pages themselves in a semi-RCU fashion (see comment below).
+ * Useful if your architecture doesn't use IPIs for remote TLB invalidates
+ * and therefore doesn't naturally serialize with software page-table walkers.
+ *
+ * When used, an architecture is expected to provide __tlb_remove_table()
+ * which does the actual freeing of these pages.
+ *
+ * HAVE_RCU_TABLE_NO_INVALIDATE
+ *
+ * This makes HAVE_RCU_TABLE_FREE avoid calling tlb_flush_mmu_tlbonly() before
+ * freeing the page-table pages. This can be avoided if you use
+ * HAVE_RCU_TABLE_FREE and your architecture does _NOT_ use the Linux
+ * page-tables natively.
+ *
+ * MMU_GATHER_NO_RANGE
+ *
+ * Use this if your architecture lacks an efficient flush_tlb_range().
+ */
+
#ifdef CONFIG_HAVE_RCU_TABLE_FREE
/*
* Semi RCU freeing of the page directories.
#define MAX_TABLE_BATCH \
((PAGE_SIZE - sizeof(struct mmu_table_batch)) / sizeof(void *))
-extern void tlb_table_flush(struct mmu_gather *tlb);
extern void tlb_remove_table(struct mmu_gather *tlb, void *table);
#endif
+#ifndef CONFIG_HAVE_MMU_GATHER_NO_GATHER
/*
* If we can't allocate a page to make a big batch of page pointers
* to work on, then just handle a few from the on-stack structure.
*/
#define MAX_GATHER_BATCH_COUNT (10000UL/MAX_GATHER_BATCH)
-/* struct mmu_gather is an opaque type used by the mm code for passing around
+extern bool __tlb_remove_page_size(struct mmu_gather *tlb, struct page *page,
+ int page_size);
+#endif
+
+/*
+ * struct mmu_gather is an opaque type used by the mm code for passing around
* any data needed by arch specific code for tlb_remove_page.
*/
struct mmu_gather {
struct mm_struct *mm;
+
#ifdef CONFIG_HAVE_RCU_TABLE_FREE
struct mmu_table_batch *batch;
#endif
+
unsigned long start;
unsigned long end;
/*
unsigned int cleared_puds : 1;
unsigned int cleared_p4ds : 1;
+ /*
+ * tracks VM_EXEC | VM_HUGETLB in tlb_start_vma
+ */
+ unsigned int vma_exec : 1;
+ unsigned int vma_huge : 1;
+
+ unsigned int batch_count;
+
+#ifndef CONFIG_HAVE_MMU_GATHER_NO_GATHER
struct mmu_gather_batch *active;
struct mmu_gather_batch local;
struct page *__pages[MMU_GATHER_BUNDLE];
- unsigned int batch_count;
- int page_size;
-};
-#define HAVE_GENERIC_MMU_GATHER
+#ifdef CONFIG_HAVE_MMU_GATHER_PAGE_SIZE
+ unsigned int page_size;
+#endif
+#endif
+};
void arch_tlb_gather_mmu(struct mmu_gather *tlb,
struct mm_struct *mm, unsigned long start, unsigned long end);
void tlb_flush_mmu(struct mmu_gather *tlb);
void arch_tlb_finish_mmu(struct mmu_gather *tlb,
unsigned long start, unsigned long end, bool force);
-void tlb_flush_mmu_free(struct mmu_gather *tlb);
-extern bool __tlb_remove_page_size(struct mmu_gather *tlb, struct page *page,
- int page_size);
static inline void __tlb_adjust_range(struct mmu_gather *tlb,
unsigned long address,
tlb->cleared_pmds = 0;
tlb->cleared_puds = 0;
tlb->cleared_p4ds = 0;
+ /*
+ * Do not reset mmu_gather::vma_* fields here, we do not
+ * call into tlb_start_vma() again to set them if there is an
+ * intermediate flush.
+ */
+}
+
+#ifdef CONFIG_MMU_GATHER_NO_RANGE
+
+#if defined(tlb_flush) || defined(tlb_start_vma) || defined(tlb_end_vma)
+#error MMU_GATHER_NO_RANGE relies on default tlb_flush(), tlb_start_vma() and tlb_end_vma()
+#endif
+
+/*
+ * When an architecture does not have efficient means of range flushing TLBs
+ * there is no point in doing intermediate flushes on tlb_end_vma() to keep the
+ * range small. We equally don't have to worry about page granularity or other
+ * things.
+ *
+ * All we need to do is issue a full flush for any !0 range.
+ */
+static inline void tlb_flush(struct mmu_gather *tlb)
+{
+ if (tlb->end)
+ flush_tlb_mm(tlb->mm);
+}
+
+static inline void
+tlb_update_vma_flags(struct mmu_gather *tlb, struct vm_area_struct *vma) { }
+
+#define tlb_end_vma tlb_end_vma
+static inline void tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vma) { }
+
+#else /* CONFIG_MMU_GATHER_NO_RANGE */
+
+#ifndef tlb_flush
+
+#if defined(tlb_start_vma) || defined(tlb_end_vma)
+#error Default tlb_flush() relies on default tlb_start_vma() and tlb_end_vma()
+#endif
+
+/*
+ * When an architecture does not provide its own tlb_flush() implementation
+ * but does have a reasonably efficient flush_vma_range() implementation
+ * use that.
+ */
+static inline void tlb_flush(struct mmu_gather *tlb)
+{
+ if (tlb->fullmm || tlb->need_flush_all) {
+ flush_tlb_mm(tlb->mm);
+ } else if (tlb->end) {
+ struct vm_area_struct vma = {
+ .vm_mm = tlb->mm,
+ .vm_flags = (tlb->vma_exec ? VM_EXEC : 0) |
+ (tlb->vma_huge ? VM_HUGETLB : 0),
+ };
+
+ flush_tlb_range(&vma, tlb->start, tlb->end);
+ }
}
+static inline void
+tlb_update_vma_flags(struct mmu_gather *tlb, struct vm_area_struct *vma)
+{
+ /*
+ * flush_tlb_range() implementations that look at VM_HUGETLB (tile,
+ * mips-4k) flush only large pages.
+ *
+ * flush_tlb_range() implementations that flush I-TLB also flush D-TLB
+ * (tile, xtensa, arm), so it's ok to just add VM_EXEC to an existing
+ * range.
+ *
+ * We rely on tlb_end_vma() to issue a flush, such that when we reset
+ * these values the batch is empty.
+ */
+ tlb->vma_huge = !!(vma->vm_flags & VM_HUGETLB);
+ tlb->vma_exec = !!(vma->vm_flags & VM_EXEC);
+}
+
+#else
+
+static inline void
+tlb_update_vma_flags(struct mmu_gather *tlb, struct vm_area_struct *vma) { }
+
+#endif
+
+#endif /* CONFIG_MMU_GATHER_NO_RANGE */
+
static inline void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb)
{
if (!tlb->end)
return tlb_remove_page_size(tlb, page, PAGE_SIZE);
}
-#ifndef tlb_remove_check_page_size_change
-#define tlb_remove_check_page_size_change tlb_remove_check_page_size_change
-static inline void tlb_remove_check_page_size_change(struct mmu_gather *tlb,
+static inline void tlb_change_page_size(struct mmu_gather *tlb,
unsigned int page_size)
{
- /*
- * We don't care about page size change, just update
- * mmu_gather page size here so that debug checks
- * doesn't throw false warning.
- */
-#ifdef CONFIG_DEBUG_VM
+#ifdef CONFIG_HAVE_MMU_GATHER_PAGE_SIZE
+ if (tlb->page_size && tlb->page_size != page_size) {
+ if (!tlb->fullmm)
+ tlb_flush_mmu(tlb);
+ }
+
tlb->page_size = page_size;
#endif
}
-#endif
static inline unsigned long tlb_get_unmap_shift(struct mmu_gather *tlb)
{
* the vmas are adjusted to only cover the region to be torn down.
*/
#ifndef tlb_start_vma
-#define tlb_start_vma(tlb, vma) do { } while (0)
-#endif
+static inline void tlb_start_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
+{
+ if (tlb->fullmm)
+ return;
-#define __tlb_end_vma(tlb, vma) \
- do { \
- if (!tlb->fullmm) \
- tlb_flush_mmu_tlbonly(tlb); \
- } while (0)
+ tlb_update_vma_flags(tlb, vma);
+ flush_cache_range(vma, vma->vm_start, vma->vm_end);
+}
+#endif
#ifndef tlb_end_vma
-#define tlb_end_vma __tlb_end_vma
+static inline void tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
+{
+ if (tlb->fullmm)
+ return;
+
+ /*
+ * Do a TLB flush and reset the range at VMA boundaries; this avoids
+ * the ranges growing with the unused space between consecutive VMAs,
+ * but also the mmu_gather::vma_* flags from tlb_start_vma() rely on
+ * this.
+ */
+ tlb_flush_mmu_tlbonly(tlb);
+}
#endif
#ifndef __tlb_remove_tlb_entry
#endif /* CONFIG_MMU */
-#define tlb_migrate_finish(mm) do {} while (0)
-
#endif /* _ASM_GENERIC__TLB_H */
projects / linux-2.6-microblaze.git / blobdiff