Commit
2c4541e24c55 ("mm: use vma_init() to initialize VMAs on stack and
data segments") tried to initialize various left-over ad-hoc vma's
"properly", but actually made things worse for the temporary vma's used
for TLB flushing.
vma_init() doesn't actually initialize all of the vma, just a few
fields, so doing something like
- struct vm_area_struct vma = { .vm_mm = tlb->mm, };
+ struct vm_area_struct vma;
+
+ vma_init(&vma, tlb->mm);
was actually very bad: instead of having a nicely initialized vma with
every field but "vm_mm" zeroed, you'd have an entirely uninitialized vma
with only a couple of fields initialized. And they weren't even fields
that the code in question mostly cared about.
The flush_tlb_range() function takes a "struct vma" rather than a
"struct mm_struct", because a few architectures actually care about what
kind of range it is - being able to only do an ITLB flush if it's a
range that doesn't have data accesses enabled, for example. And all the
normal users already have the vma for doing the range invalidation.
But a few people want to call flush_tlb_range() with a range they just
made up, so they also end up using a made-up vma. x86 just has a
special "flush_tlb_mm_range()" function for this, but other
architectures (arm and ia64) do the "use fake vma" thing instead, and
thus got caught up in the vma_init() changes.
At the same time, the TLB flushing code really doesn't care about most
other fields in the vma, so vma_init() is just unnecessary and
pointless.
This fixes things by having an explicit "this is just an initializer for
the TLB flush" initializer macro, which is used by the arm/arm64/ia64
people who mis-use this interface with just a dummy vma.
Fixes:
2c4541e24c55 ("mm: use vma_init() to initialize VMAs on stack and data segments")
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
*/
static void ecard_init_pgtables(struct mm_struct *mm)
{
- struct vm_area_struct vma;
+ struct vm_area_struct vma = TLB_FLUSH_VMA(mm, VM_EXEC);
/* We want to set up the page tables for the following mapping:
* Virtual Physical
memcpy(dst_pgd, src_pgd, sizeof(pgd_t) * (EASI_SIZE / PGDIR_SIZE));
- vma_init(&vma, mm);
- vma.vm_flags = VM_EXEC;
-
flush_tlb_range(&vma, IO_START, IO_START + IO_SIZE);
flush_tlb_range(&vma, EASI_START, EASI_START + EASI_SIZE);
}
static inline void tlb_flush(struct mmu_gather *tlb)
{
- struct vm_area_struct vma;
-
- vma_init(&vma, tlb->mm);
+ struct vm_area_struct vma = TLB_FLUSH_VMA(tlb->mm, 0);
/*
* The ASID allocator will either invalidate the ASID or mark
unsigned long pgsize,
unsigned long ncontig)
{
- struct vm_area_struct vma;
pte_t orig_pte = huge_ptep_get(ptep);
bool valid = pte_valid(orig_pte);
unsigned long i, saddr = addr;
- vma_init(&vma, mm);
-
for (i = 0; i < ncontig; i++, addr += pgsize, ptep++) {
pte_t pte = ptep_get_and_clear(mm, addr, ptep);
orig_pte = pte_mkdirty(orig_pte);
}
- if (valid)
+ if (valid) {
+ struct vm_area_struct vma = TLB_FLUSH_VMA(mm, 0);
flush_tlb_range(&vma, saddr, addr);
+ }
return orig_pte;
}
unsigned long pgsize,
unsigned long ncontig)
{
- struct vm_area_struct vma;
+ struct vm_area_struct vma = TLB_FLUSH_VMA(mm, 0);
unsigned long i, saddr = addr;
- vma_init(&vma, mm);
for (i = 0; i < ncontig; i++, addr += pgsize, ptep++)
pte_clear(mm, addr, ptep);
flush_tlb_all();
} else {
/*
- * XXX fix me: flush_tlb_range() should take an mm pointer instead of a
- * vma pointer.
+ * flush_tlb_range() takes a vma instead of a mm pointer because
+ * some architectures want the vm_flags for ITLB/DTLB flush.
*/
- struct vm_area_struct vma;
+ struct vm_area_struct vma = TLB_FLUSH_VMA(tlb->mm, 0);
- vma_init(&vma, tlb->mm);
/* flush the address range from the tlb: */
flush_tlb_range(&vma, start, end);
/* now flush the virt. page-table area mapping the address range: */
vma->vm_ops = NULL;
}
+/* flush_tlb_range() takes a vma, not a mm, and can care about flags */
+#define TLB_FLUSH_VMA(mm,flags) { .vm_mm = (mm), .vm_flags = (flags) }
+
struct mmu_gather;
struct inode;
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