diff options
| author | Will Deacon <will@kernel.org> | 2021-08-06 12:31:04 +0100 |
|---|---|---|
| committer | Catalin Marinas <catalin.marinas@arm.com> | 2021-08-06 13:52:03 +0100 |
| commit | 5e10f9887ed85d4f59266d5c60dd09be96b5dbd4 (patch) | |
| tree | ff4dcc17684744bb95c253fb15f20d9b7c44e2b0 /arch/arm64/include/asm/tlbflush.h | |
| parent | ede3241a5f235811b1e66f56cf8fbdfd01266efb (diff) | |
| download | linux-5e10f9887ed85d4f59266d5c60dd09be96b5dbd4.tar.bz2 | |
arm64: mm: Fix TLBI vs ASID rollover
When switching to an 'mm_struct' for the first time following an ASID
rollover, a new ASID may be allocated and assigned to 'mm->context.id'.
This reassignment can happen concurrently with other operations on the
mm, such as unmapping pages and subsequently issuing TLB invalidation.
Consequently, we need to ensure that (a) accesses to 'mm->context.id'
are atomic and (b) all page-table updates made prior to a TLBI using the
old ASID are guaranteed to be visible to CPUs running with the new ASID.
This was found by inspection after reviewing the VMID changes from
Shameer but it looks like a real (yet hard to hit) bug.
Cc: <stable@vger.kernel.org>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Jade Alglave <jade.alglave@arm.com>
Cc: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Signed-off-by: Will Deacon <will@kernel.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/20210806113109.2475-2-will@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/include/asm/tlbflush.h')
| -rw-r--r-- | arch/arm64/include/asm/tlbflush.h | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h index 118dabbda553..412a3b9a3c25 100644 --- a/arch/arm64/include/asm/tlbflush.h +++ b/arch/arm64/include/asm/tlbflush.h @@ -245,9 +245,10 @@ static inline void flush_tlb_all(void) static inline void flush_tlb_mm(struct mm_struct *mm) { - unsigned long asid = __TLBI_VADDR(0, ASID(mm)); + unsigned long asid; dsb(ishst); + asid = __TLBI_VADDR(0, ASID(mm)); __tlbi(aside1is, asid); __tlbi_user(aside1is, asid); dsb(ish); @@ -256,9 +257,10 @@ static inline void flush_tlb_mm(struct mm_struct *mm) static inline void flush_tlb_page_nosync(struct vm_area_struct *vma, unsigned long uaddr) { - unsigned long addr = __TLBI_VADDR(uaddr, ASID(vma->vm_mm)); + unsigned long addr; dsb(ishst); + addr = __TLBI_VADDR(uaddr, ASID(vma->vm_mm)); __tlbi(vale1is, addr); __tlbi_user(vale1is, addr); } @@ -283,9 +285,7 @@ static inline void __flush_tlb_range(struct vm_area_struct *vma, { int num = 0; int scale = 0; - unsigned long asid = ASID(vma->vm_mm); - unsigned long addr; - unsigned long pages; + unsigned long asid, addr, pages; start = round_down(start, stride); end = round_up(end, stride); @@ -305,6 +305,7 @@ static inline void __flush_tlb_range(struct vm_area_struct *vma, } dsb(ishst); + asid = ASID(vma->vm_mm); /* * When the CPU does not support TLB range operations, flush the TLB |