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-rw-r--r--arch/arm64/include/asm/tlbflush.h112
1 files changed, 70 insertions, 42 deletions
diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h
index a4a1901140ee..c3c0387aee18 100644
--- a/arch/arm64/include/asm/tlbflush.h
+++ b/arch/arm64/include/asm/tlbflush.h
@@ -70,43 +70,73 @@
})
/*
- * TLB Management
- * ==============
+ * TLB Invalidation
+ * ================
*
- * The TLB specific code is expected to perform whatever tests it needs
- * to determine if it should invalidate the TLB for each call. Start
- * addresses are inclusive and end addresses are exclusive; it is safe to
- * round these addresses down.
+ * This header file implements the low-level TLB invalidation routines
+ * (sometimes referred to as "flushing" in the kernel) for arm64.
*
- * flush_tlb_all()
+ * Every invalidation operation uses the following template:
+ *
+ * DSB ISHST // Ensure prior page-table updates have completed
+ * TLBI ... // Invalidate the TLB
+ * DSB ISH // Ensure the TLB invalidation has completed
+ * if (invalidated kernel mappings)
+ * ISB // Discard any instructions fetched from the old mapping
+ *
+ *
+ * The following functions form part of the "core" TLB invalidation API,
+ * as documented in Documentation/core-api/cachetlb.rst:
*
- * Invalidate the entire TLB.
+ * flush_tlb_all()
+ * Invalidate the entire TLB (kernel + user) on all CPUs
*
* flush_tlb_mm(mm)
+ * Invalidate an entire user address space on all CPUs.
+ * The 'mm' argument identifies the ASID to invalidate.
+ *
+ * flush_tlb_range(vma, start, end)
+ * Invalidate the virtual-address range '[start, end)' on all
+ * CPUs for the user address space corresponding to 'vma->mm'.
+ * Note that this operation also invalidates any walk-cache
+ * entries associated with translations for the specified address
+ * range.
+ *
+ * flush_tlb_kernel_range(start, end)
+ * Same as flush_tlb_range(..., start, end), but applies to
+ * kernel mappings rather than a particular user address space.
+ * Whilst not explicitly documented, this function is used when
+ * unmapping pages from vmalloc/io space.
+ *
+ * flush_tlb_page(vma, addr)
+ * Invalidate a single user mapping for address 'addr' in the
+ * address space corresponding to 'vma->mm'. Note that this
+ * operation only invalidates a single, last-level page-table
+ * entry and therefore does not affect any walk-caches.
*
- * Invalidate all TLB entries in a particular address space.
- * - mm - mm_struct describing address space
*
- * flush_tlb_range(mm,start,end)
+ * Next, we have some undocumented invalidation routines that you probably
+ * don't want to call unless you know what you're doing:
*
- * Invalidate a range of TLB entries in the specified address
- * space.
- * - mm - mm_struct describing address space
- * - start - start address (may not be aligned)
- * - end - end address (exclusive, may not be aligned)
+ * local_flush_tlb_all()
+ * Same as flush_tlb_all(), but only applies to the calling CPU.
*
- * flush_tlb_page(vaddr,vma)
+ * __flush_tlb_kernel_pgtable(addr)
+ * Invalidate a single kernel mapping for address 'addr' on all
+ * CPUs, ensuring that any walk-cache entries associated with the
+ * translation are also invalidated.
*
- * Invalidate the specified page in the specified address range.
- * - vaddr - virtual address (may not be aligned)
- * - vma - vma_struct describing address range
+ * __flush_tlb_range(vma, start, end, stride, last_level)
+ * Invalidate the virtual-address range '[start, end)' on all
+ * CPUs for the user address space corresponding to 'vma->mm'.
+ * The invalidation operations are issued at a granularity
+ * determined by 'stride' and only affect any walk-cache entries
+ * if 'last_level' is equal to false.
*
- * flush_kern_tlb_page(kaddr)
*
- * Invalidate the TLB entry for the specified page. The address
- * will be in the kernels virtual memory space. Current uses
- * only require the D-TLB to be invalidated.
- * - kaddr - Kernel virtual memory address
+ * Finally, take a look at asm/tlb.h to see how tlb_flush() is implemented
+ * on top of these routines, since that is our interface to the mmu_gather
+ * API as used by munmap() and friends.
*/
static inline void local_flush_tlb_all(void)
{
@@ -149,25 +179,28 @@ static inline void flush_tlb_page(struct vm_area_struct *vma,
* This is meant to avoid soft lock-ups on large TLB flushing ranges and not
* necessarily a performance improvement.
*/
-#define MAX_TLB_RANGE (1024UL << PAGE_SHIFT)
+#define MAX_TLBI_OPS 1024UL
static inline void __flush_tlb_range(struct vm_area_struct *vma,
unsigned long start, unsigned long end,
- bool last_level)
+ unsigned long stride, bool last_level)
{
unsigned long asid = ASID(vma->vm_mm);
unsigned long addr;
- if ((end - start) > MAX_TLB_RANGE) {
+ if ((end - start) > (MAX_TLBI_OPS * stride)) {
flush_tlb_mm(vma->vm_mm);
return;
}
+ /* Convert the stride into units of 4k */
+ stride >>= 12;
+
start = __TLBI_VADDR(start, asid);
end = __TLBI_VADDR(end, asid);
dsb(ishst);
- for (addr = start; addr < end; addr += 1 << (PAGE_SHIFT - 12)) {
+ for (addr = start; addr < end; addr += stride) {
if (last_level) {
__tlbi(vale1is, addr);
__tlbi_user(vale1is, addr);
@@ -182,14 +215,18 @@ static inline void __flush_tlb_range(struct vm_area_struct *vma,
static inline void flush_tlb_range(struct vm_area_struct *vma,
unsigned long start, unsigned long end)
{
- __flush_tlb_range(vma, start, end, false);
+ /*
+ * We cannot use leaf-only invalidation here, since we may be invalidating
+ * table entries as part of collapsing hugepages or moving page tables.
+ */
+ __flush_tlb_range(vma, start, end, PAGE_SIZE, false);
}
static inline void flush_tlb_kernel_range(unsigned long start, unsigned long end)
{
unsigned long addr;
- if ((end - start) > MAX_TLB_RANGE) {
+ if ((end - start) > (MAX_TLBI_OPS * PAGE_SIZE)) {
flush_tlb_all();
return;
}
@@ -199,7 +236,7 @@ static inline void flush_tlb_kernel_range(unsigned long start, unsigned long end
dsb(ishst);
for (addr = start; addr < end; addr += 1 << (PAGE_SHIFT - 12))
- __tlbi(vaae1is, addr);
+ __tlbi(vaale1is, addr);
dsb(ish);
isb();
}
@@ -208,20 +245,11 @@ static inline void flush_tlb_kernel_range(unsigned long start, unsigned long end
* Used to invalidate the TLB (walk caches) corresponding to intermediate page
* table levels (pgd/pud/pmd).
*/
-static inline void __flush_tlb_pgtable(struct mm_struct *mm,
- unsigned long uaddr)
-{
- unsigned long addr = __TLBI_VADDR(uaddr, ASID(mm));
-
- __tlbi(vae1is, addr);
- __tlbi_user(vae1is, addr);
- dsb(ish);
-}
-
static inline void __flush_tlb_kernel_pgtable(unsigned long kaddr)
{
unsigned long addr = __TLBI_VADDR(kaddr, 0);
+ dsb(ishst);
__tlbi(vaae1is, addr);
dsb(ish);
}