Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 723 insertions, 0 deletions

diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h
new file mode 100644
index 0000000000..129a3a7599
--- /dev/null
+++ b/include/asm-generic/tlb.h
@@ -0,0 +1,723 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/* include/asm-generic/tlb.h
+ *
+ *	Generic TLB shootdown code
+ *
+ * Copyright 2001 Red Hat, Inc.
+ * Based on code from mm/memory.c Copyright Linus Torvalds and others.
+ *
+ * Copyright 2011 Red Hat, Inc., Peter Zijlstra
+ */
+#ifndef _ASM_GENERIC__TLB_H
+#define _ASM_GENERIC__TLB_H
+
+#include <linux/mmu_notifier.h>
+#include <linux/swap.h>
+#include <linux/hugetlb_inline.h>
+#include <asm/tlbflush.h>
+#include <asm/cacheflush.h>
+
+/*
+ * Blindly accessing user memory from NMI context can be dangerous
+ * if we're in the middle of switching the current user task or switching
+ * the loaded mm.
+ */
+#ifndef nmi_uaccess_okay
+# define nmi_uaccess_okay() true
+#endif
+
+#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_gather_mmu_fullmm() / 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_table()
+ *
+ *    tlb_remove_table() is the basic primitive to free page-table directories
+ *    (__p*_free_tlb()).  In it's most primitive form it is an alias for
+ *    tlb_remove_page() below, for when page directories are pages and have no
+ *    additional constraints.
+ *
+ *    See also MMU_GATHER_TABLE_FREE and MMU_GATHER_RCU_TABLE_FREE.
+ *
+ *  - 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_fullmm() 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:
+ *
+ *  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().
+ *
+ *  This might be useful if your architecture has size specific TLB
+ *  invalidation instructions.
+ *
+ *  MMU_GATHER_TABLE_FREE
+ *
+ *  This provides tlb_remove_table(), to be used instead of tlb_remove_page()
+ *  for page directores (__p*_free_tlb()).
+ *
+ *  Useful if your architecture has non-page page directories.
+ *
+ *  When used, an architecture is expected to provide __tlb_remove_table()
+ *  which does the actual freeing of these pages.
+ *
+ *  MMU_GATHER_RCU_TABLE_FREE
+ *
+ *  Like MMU_GATHER_TABLE_FREE, and adds semi-RCU semantics to the free (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.
+ *
+ *  MMU_GATHER_NO_FLUSH_CACHE
+ *
+ *  Indicates the architecture has flush_cache_range() but it needs *NOT* be called
+ *  before unmapping a VMA.
+ *
+ *  NOTE: strictly speaking we shouldn't have this knob and instead rely on
+ *	  flush_cache_range() being a NOP, except Sparc64 seems to be
+ *	  different here.
+ *
+ *  MMU_GATHER_MERGE_VMAS
+ *
+ *  Indicates the architecture wants to merge ranges over VMAs; typical when
+ *  multiple range invalidates are more expensive than a full invalidate.
+ *
+ *  MMU_GATHER_NO_RANGE
+ *
+ *  Use this if your architecture lacks an efficient flush_tlb_range(). This
+ *  option implies MMU_GATHER_MERGE_VMAS above.
+ *
+ *  MMU_GATHER_NO_GATHER
+ *
+ *  If the option is set the mmu_gather will not track individual pages for
+ *  delayed page free anymore. A platform that enables the option needs to
+ *  provide its own implementation of the __tlb_remove_page_size() function to
+ *  free pages.
+ *
+ *  This is useful if your architecture already flushes TLB entries in the
+ *  various ptep_get_and_clear() functions.
+ */
+
+#ifdef CONFIG_MMU_GATHER_TABLE_FREE
+
+struct mmu_table_batch {
+#ifdef CONFIG_MMU_GATHER_RCU_TABLE_FREE
+	struct rcu_head		rcu;
+#endif
+	unsigned int		nr;
+	void			*tables[];
+};
+
+#define MAX_TABLE_BATCH		\
+	((PAGE_SIZE - sizeof(struct mmu_table_batch)) / sizeof(void *))
+
+extern void tlb_remove_table(struct mmu_gather *tlb, void *table);
+
+#else /* !CONFIG_MMU_GATHER_HAVE_TABLE_FREE */
+
+/*
+ * Without MMU_GATHER_TABLE_FREE the architecture is assumed to have page based
+ * page directories and we can use the normal page batching to free them.
+ */
+#define tlb_remove_table(tlb, page) tlb_remove_page((tlb), (page))
+
+#endif /* CONFIG_MMU_GATHER_TABLE_FREE */
+
+#ifdef CONFIG_MMU_GATHER_RCU_TABLE_FREE
+/*
+ * This allows an architecture that does not use the linux page-tables for
+ * hardware to skip the TLBI when freeing page tables.
+ */
+#ifndef tlb_needs_table_invalidate
+#define tlb_needs_table_invalidate() (true)
+#endif
+
+void tlb_remove_table_sync_one(void);
+
+#else
+
+#ifdef tlb_needs_table_invalidate
+#error tlb_needs_table_invalidate() requires MMU_GATHER_RCU_TABLE_FREE
+#endif
+
+static inline void tlb_remove_table_sync_one(void) { }
+
+#endif /* CONFIG_MMU_GATHER_RCU_TABLE_FREE */
+
+
+#ifndef CONFIG_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 MMU_GATHER_BUNDLE	8
+
+struct mmu_gather_batch {
+	struct mmu_gather_batch	*next;
+	unsigned int		nr;
+	unsigned int		max;
+	struct encoded_page	*encoded_pages[];
+};
+
+#define MAX_GATHER_BATCH	\
+	((PAGE_SIZE - sizeof(struct mmu_gather_batch)) / sizeof(void *))
+
+/*
+ * Limit the maximum number of mmu_gather batches to reduce a risk of soft
+ * lockups for non-preemptible kernels on huge machines when a lot of memory
+ * is zapped during unmapping.
+ * 10K pages freed at once should be safe even without a preemption point.
+ */
+#define MAX_GATHER_BATCH_COUNT	(10000UL/MAX_GATHER_BATCH)
+
+extern bool __tlb_remove_page_size(struct mmu_gather *tlb,
+				   struct encoded_page *page,
+				   int page_size);
+
+#ifdef CONFIG_SMP
+/*
+ * This both sets 'delayed_rmap', and returns true. It would be an inline
+ * function, except we define it before the 'struct mmu_gather'.
+ */
+#define tlb_delay_rmap(tlb) (((tlb)->delayed_rmap = 1), true)
+extern void tlb_flush_rmaps(struct mmu_gather *tlb, struct vm_area_struct *vma);
+#endif
+
+#endif
+
+/*
+ * We have a no-op version of the rmap removal that doesn't
+ * delay anything. That is used on S390, which flushes remote
+ * TLBs synchronously, and on UP, which doesn't have any
+ * remote TLBs to flush and is not preemptible due to this
+ * all happening under the page table lock.
+ */
+#ifndef tlb_delay_rmap
+#define tlb_delay_rmap(tlb) (false)
+static inline void tlb_flush_rmaps(struct mmu_gather *tlb, struct vm_area_struct *vma) { }
+#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_MMU_GATHER_TABLE_FREE
+	struct mmu_table_batch	*batch;
+#endif
+
+	unsigned long		start;
+	unsigned long		end;
+	/*
+	 * we are in the middle of an operation to clear
+	 * a full mm and can make some optimizations
+	 */
+	unsigned int		fullmm : 1;
+
+	/*
+	 * we have performed an operation which
+	 * requires a complete flush of the tlb
+	 */
+	unsigned int		need_flush_all : 1;
+
+	/*
+	 * we have removed page directories
+	 */
+	unsigned int		freed_tables : 1;
+
+	/*
+	 * Do we have pending delayed rmap removals?
+	 */
+	unsigned int		delayed_rmap : 1;
+
+	/*
+	 * at which levels have we cleared entries?
+	 */
+	unsigned int		cleared_ptes : 1;
+	unsigned int		cleared_pmds : 1;
+	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		vma_pfn  : 1;
+
+	unsigned int		batch_count;
+
+#ifndef CONFIG_MMU_GATHER_NO_GATHER
+	struct mmu_gather_batch *active;
+	struct mmu_gather_batch	local;
+	struct page		*__pages[MMU_GATHER_BUNDLE];
+
+#ifdef CONFIG_MMU_GATHER_PAGE_SIZE
+	unsigned int page_size;
+#endif
+#endif
+};
+
+void tlb_flush_mmu(struct mmu_gather *tlb);
+
+static inline void __tlb_adjust_range(struct mmu_gather *tlb,
+				      unsigned long address,
+				      unsigned int range_size)
+{
+	tlb->start = min(tlb->start, address);
+	tlb->end = max(tlb->end, address + range_size);
+}
+
+static inline void __tlb_reset_range(struct mmu_gather *tlb)
+{
+	if (tlb->fullmm) {
+		tlb->start = tlb->end = ~0;
+	} else {
+		tlb->start = TASK_SIZE;
+		tlb->end = 0;
+	}
+	tlb->freed_tables = 0;
+	tlb->cleared_ptes = 0;
+	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)
+#error MMU_GATHER_NO_RANGE relies on default tlb_flush()
+#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);
+}
+
+#else /* CONFIG_MMU_GATHER_NO_RANGE */
+
+#ifndef tlb_flush
+/*
+ * 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);
+	}
+}
+#endif
+
+#endif /* CONFIG_MMU_GATHER_NO_RANGE */
+
+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 = is_vm_hugetlb_page(vma);
+	tlb->vma_exec = !!(vma->vm_flags & VM_EXEC);
+	tlb->vma_pfn  = !!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP));
+}
+
+static inline void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb)
+{
+	/*
+	 * Anything calling __tlb_adjust_range() also sets at least one of
+	 * these bits.
+	 */
+	if (!(tlb->freed_tables || tlb->cleared_ptes || tlb->cleared_pmds ||
+	      tlb->cleared_puds || tlb->cleared_p4ds))
+		return;
+
+	tlb_flush(tlb);
+	__tlb_reset_range(tlb);
+}
+
+static inline void tlb_remove_page_size(struct mmu_gather *tlb,
+					struct page *page, int page_size)
+{
+	if (__tlb_remove_page_size(tlb, encode_page(page, 0), page_size))
+		tlb_flush_mmu(tlb);
+}
+
+static __always_inline bool __tlb_remove_page(struct mmu_gather *tlb, struct page *page, unsigned int flags)
+{
+	return __tlb_remove_page_size(tlb, encode_page(page, flags), PAGE_SIZE);
+}
+
+/* tlb_remove_page
+ *	Similar to __tlb_remove_page but will call tlb_flush_mmu() itself when
+ *	required.
+ */
+static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
+{
+	return tlb_remove_page_size(tlb, page, PAGE_SIZE);
+}
+
+static inline void tlb_remove_ptdesc(struct mmu_gather *tlb, void *pt)
+{
+	tlb_remove_table(tlb, pt);
+}
+
+/* Like tlb_remove_ptdesc, but for page-like page directories. */
+static inline void tlb_remove_page_ptdesc(struct mmu_gather *tlb, struct ptdesc *pt)
+{
+	tlb_remove_page(tlb, ptdesc_page(pt));
+}
+
+static inline void tlb_change_page_size(struct mmu_gather *tlb,
+						     unsigned int page_size)
+{
+#ifdef CONFIG_MMU_GATHER_PAGE_SIZE
+	if (tlb->page_size && tlb->page_size != page_size) {
+		if (!tlb->fullmm && !tlb->need_flush_all)
+			tlb_flush_mmu(tlb);
+	}
+
+	tlb->page_size = page_size;
+#endif
+}
+
+static inline unsigned long tlb_get_unmap_shift(struct mmu_gather *tlb)
+{
+	if (tlb->cleared_ptes)
+		return PAGE_SHIFT;
+	if (tlb->cleared_pmds)
+		return PMD_SHIFT;
+	if (tlb->cleared_puds)
+		return PUD_SHIFT;
+	if (tlb->cleared_p4ds)
+		return P4D_SHIFT;
+
+	return PAGE_SHIFT;
+}
+
+static inline unsigned long tlb_get_unmap_size(struct mmu_gather *tlb)
+{
+	return 1UL << tlb_get_unmap_shift(tlb);
+}
+
+/*
+ * In the case of tlb vma handling, we can optimise these away in the
+ * case where we're doing a full MM flush.  When we're doing a munmap,
+ * the vmas are adjusted to only cover the region to be torn down.
+ */
+static inline void tlb_start_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
+{
+	if (tlb->fullmm)
+		return;
+
+	tlb_update_vma_flags(tlb, vma);
+#ifndef CONFIG_MMU_GATHER_NO_FLUSH_CACHE
+	flush_cache_range(vma, vma->vm_start, vma->vm_end);
+#endif
+}
+
+static inline void tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
+{
+	if (tlb->fullmm)
+		return;
+
+	/*
+	 * VM_PFNMAP is more fragile because the core mm will not track the
+	 * page mapcount -- there might not be page-frames for these PFNs after
+	 * all. Force flush TLBs for such ranges to avoid munmap() vs
+	 * unmap_mapping_range() races.
+	 */
+	if (tlb->vma_pfn || !IS_ENABLED(CONFIG_MMU_GATHER_MERGE_VMAS)) {
+		/*
+		 * Do a TLB flush and reset the range at VMA boundaries; this avoids
+		 * the ranges growing with the unused space between consecutive VMAs.
+		 */
+		tlb_flush_mmu_tlbonly(tlb);
+	}
+}
+
+/*
+ * tlb_flush_{pte|pmd|pud|p4d}_range() adjust the tlb->start and tlb->end,
+ * and set corresponding cleared_*.
+ */
+static inline void tlb_flush_pte_range(struct mmu_gather *tlb,
+				     unsigned long address, unsigned long size)
+{
+	__tlb_adjust_range(tlb, address, size);
+	tlb->cleared_ptes = 1;
+}
+
+static inline void tlb_flush_pmd_range(struct mmu_gather *tlb,
+				     unsigned long address, unsigned long size)
+{
+	__tlb_adjust_range(tlb, address, size);
+	tlb->cleared_pmds = 1;
+}
+
+static inline void tlb_flush_pud_range(struct mmu_gather *tlb,
+				     unsigned long address, unsigned long size)
+{
+	__tlb_adjust_range(tlb, address, size);
+	tlb->cleared_puds = 1;
+}
+
+static inline void tlb_flush_p4d_range(struct mmu_gather *tlb,
+				     unsigned long address, unsigned long size)
+{
+	__tlb_adjust_range(tlb, address, size);
+	tlb->cleared_p4ds = 1;
+}
+
+#ifndef __tlb_remove_tlb_entry
+#define __tlb_remove_tlb_entry(tlb, ptep, address) do { } while (0)
+#endif
+
+/**
+ * tlb_remove_tlb_entry - remember a pte unmapping for later tlb invalidation.
+ *
+ * Record the fact that pte's were really unmapped by updating the range,
+ * so we can later optimise away the tlb invalidate.   This helps when
+ * userspace is unmapping already-unmapped pages, which happens quite a lot.
+ */
+#define tlb_remove_tlb_entry(tlb, ptep, address)		\
+	do {							\
+		tlb_flush_pte_range(tlb, address, PAGE_SIZE);	\
+		__tlb_remove_tlb_entry(tlb, ptep, address);	\
+	} while (0)
+
+#define tlb_remove_huge_tlb_entry(h, tlb, ptep, address)	\
+	do {							\
+		unsigned long _sz = huge_page_size(h);		\
+		if (_sz >= P4D_SIZE)				\
+			tlb_flush_p4d_range(tlb, address, _sz);	\
+		else if (_sz >= PUD_SIZE)			\
+			tlb_flush_pud_range(tlb, address, _sz);	\
+		else if (_sz >= PMD_SIZE)			\
+			tlb_flush_pmd_range(tlb, address, _sz);	\
+		else						\
+			tlb_flush_pte_range(tlb, address, _sz);	\
+		__tlb_remove_tlb_entry(tlb, ptep, address);	\
+	} while (0)
+
+/**
+ * tlb_remove_pmd_tlb_entry - remember a pmd mapping for later tlb invalidation
+ * This is a nop so far, because only x86 needs it.
+ */
+#ifndef __tlb_remove_pmd_tlb_entry
+#define __tlb_remove_pmd_tlb_entry(tlb, pmdp, address) do {} while (0)
+#endif
+
+#define tlb_remove_pmd_tlb_entry(tlb, pmdp, address)			\
+	do {								\
+		tlb_flush_pmd_range(tlb, address, HPAGE_PMD_SIZE);	\
+		__tlb_remove_pmd_tlb_entry(tlb, pmdp, address);		\
+	} while (0)
+
+/**
+ * tlb_remove_pud_tlb_entry - remember a pud mapping for later tlb
+ * invalidation. This is a nop so far, because only x86 needs it.
+ */
+#ifndef __tlb_remove_pud_tlb_entry
+#define __tlb_remove_pud_tlb_entry(tlb, pudp, address) do {} while (0)
+#endif
+
+#define tlb_remove_pud_tlb_entry(tlb, pudp, address)			\
+	do {								\
+		tlb_flush_pud_range(tlb, address, HPAGE_PUD_SIZE);	\
+		__tlb_remove_pud_tlb_entry(tlb, pudp, address);		\
+	} while (0)
+
+/*
+ * For things like page tables caches (ie caching addresses "inside" the
+ * page tables, like x86 does), for legacy reasons, flushing an
+ * individual page had better flush the page table caches behind it. This
+ * is definitely how x86 works, for example. And if you have an
+ * architected non-legacy page table cache (which I'm not aware of
+ * anybody actually doing), you're going to have some architecturally
+ * explicit flushing for that, likely *separate* from a regular TLB entry
+ * flush, and thus you'd need more than just some range expansion..
+ *
+ * So if we ever find an architecture
+ * that would want something that odd, I think it is up to that
+ * architecture to do its own odd thing, not cause pain for others
+ * http://lkml.kernel.org/r/CA+55aFzBggoXtNXQeng5d_mRoDnaMBE5Y+URs+PHR67nUpMtaw@mail.gmail.com
+ *
+ * For now w.r.t page table cache, mark the range_size as PAGE_SIZE
+ */
+
+#ifndef pte_free_tlb
+#define pte_free_tlb(tlb, ptep, address)			\
+	do {							\
+		tlb_flush_pmd_range(tlb, address, PAGE_SIZE);	\
+		tlb->freed_tables = 1;				\
+		__pte_free_tlb(tlb, ptep, address);		\
+	} while (0)
+#endif
+
+#ifndef pmd_free_tlb
+#define pmd_free_tlb(tlb, pmdp, address)			\
+	do {							\
+		tlb_flush_pud_range(tlb, address, PAGE_SIZE);	\
+		tlb->freed_tables = 1;				\
+		__pmd_free_tlb(tlb, pmdp, address);		\
+	} while (0)
+#endif
+
+#ifndef pud_free_tlb
+#define pud_free_tlb(tlb, pudp, address)			\
+	do {							\
+		tlb_flush_p4d_range(tlb, address, PAGE_SIZE);	\
+		tlb->freed_tables = 1;				\
+		__pud_free_tlb(tlb, pudp, address);		\
+	} while (0)
+#endif
+
+#ifndef p4d_free_tlb
+#define p4d_free_tlb(tlb, pudp, address)			\
+	do {							\
+		__tlb_adjust_range(tlb, address, PAGE_SIZE);	\
+		tlb->freed_tables = 1;				\
+		__p4d_free_tlb(tlb, pudp, address);		\
+	} while (0)
+#endif
+
+#ifndef pte_needs_flush
+static inline bool pte_needs_flush(pte_t oldpte, pte_t newpte)
+{
+	return true;
+}
+#endif
+
+#ifndef huge_pmd_needs_flush
+static inline bool huge_pmd_needs_flush(pmd_t oldpmd, pmd_t newpmd)
+{
+	return true;
+}
+#endif
+
+#endif /* CONFIG_MMU */
+
+#endif /* _ASM_GENERIC__TLB_H */