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| author | Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> | 2018-06-01 11:24:02 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2018-06-03 13:40:38 +0300 |
| commit | a5db5060e0b2e27605df272224bfd470f644d8a5 (patch) | |
| tree | 1cfc27d0f084d34cc21978d63aa8e97fb4ba28ff /arch/powerpc/mm | |
| parent | ed515b6898c36775ddd99ff9ffeda4e83917acda (diff) | |
| download | linux-a5db5060e0b2e27605df272224bfd470f644d8a5.tar.xz | |
powerpc/mm/hash: hard disable irq in the SLB insert path
When inserting SLB entries for EA above 512TB, we need to hard disable irq.
This will make sure we don't take a PMU interrupt that can possibly touch
user space address via a stack dump. To prevent this, we need to hard disable
the interrupt.
Also add a comment explaining why we don't need context synchronizing isync
with slbmte.
Fixes: f384796c4 ("powerpc/mm: Add support for handling > 512TB address in SLB miss")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/mm')
| -rw-r--r-- | arch/powerpc/mm/slb.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/arch/powerpc/mm/slb.c b/arch/powerpc/mm/slb.c index 2f4b33b24b3b..cb796724a6fc 100644 --- a/arch/powerpc/mm/slb.c +++ b/arch/powerpc/mm/slb.c @@ -352,6 +352,14 @@ static void insert_slb_entry(unsigned long vsid, unsigned long ea, /* * We are irq disabled, hence should be safe to access PACA. */ + VM_WARN_ON(!irqs_disabled()); + + /* + * We can't take a PMU exception in the following code, so hard + * disable interrupts. + */ + hard_irq_disable(); + index = get_paca()->stab_rr; /* @@ -369,6 +377,11 @@ static void insert_slb_entry(unsigned long vsid, unsigned long ea, ((unsigned long) ssize << SLB_VSID_SSIZE_SHIFT); esid_data = mk_esid_data(ea, ssize, index); + /* + * No need for an isync before or after this slbmte. The exception + * we enter with and the rfid we exit with are context synchronizing. + * Also we only handle user segments here. + */ asm volatile("slbmte %0, %1" : : "r" (vsid_data), "r" (esid_data) : "memory"); |