From: Balbir Singh bsingharora@gmail.com

The current code would fail on huge pages addresses, since the shift would be incorrect. Use the correct page shift value returned by __find_linux_pte() to get the correct physical address. The code is more generic and can handle both regular and compound pages.

Fixes: ba41e1e1ccb9 ("powerpc/mce: Hookup derror (load/store) UE errors") Signed-off-by: Balbir Singh bsingharora@gmail.com [arbab@linux.ibm.com: Fixup pseries_do_memory_failure()] Signed-off-by: Reza Arbab arbab@linux.ibm.com Tested-by: Mahesh Salgaonkar mahesh@linux.vnet.ibm.com Signed-off-by: Santosh Sivaraj santosh@fossix.org Cc: stable@vger.kernel.org # v4.15+ --- arch/powerpc/kernel/mce_power.c | 19 +++++++++++++------ 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/kernel/mce_power.c b/arch/powerpc/kernel/mce_power.c index a814d2dfb5b0..714a98e0927f 100644 --- a/arch/powerpc/kernel/mce_power.c +++ b/arch/powerpc/kernel/mce_power.c @@ -26,6 +26,7 @@ unsigned long addr_to_pfn(struct pt_regs *regs, unsigned long addr) { pte_t *ptep; + unsigned int shift; unsigned long flags; struct mm_struct *mm;

@@ -35,13 +36,18 @@ unsigned long addr_to_pfn(struct pt_regs *regs, unsigned long addr) mm = &init_mm;

local_irq_save(flags); - if (mm == current->mm) - ptep = find_current_mm_pte(mm->pgd, addr, NULL, NULL); - else - ptep = find_init_mm_pte(addr, NULL); + ptep = __find_linux_pte(mm->pgd, addr, NULL, &shift); local_irq_restore(flags); + if (!ptep || pte_special(*ptep)) return ULONG_MAX; + + if (shift > PAGE_SHIFT) { + unsigned long rpnmask = (1ul << shift) - PAGE_SIZE; + + return pte_pfn(__pte(pte_val(*ptep) | (addr & rpnmask))); + } + return pte_pfn(*ptep); }

@@ -344,7 +350,7 @@ static const struct mce_derror_table mce_p9_derror_table[] = { MCE_INITIATOR_CPU, MCE_SEV_SEVERE, true }, { 0, false, 0, 0, 0, 0, 0 } };

-static int mce_find_instr_ea_and_pfn(struct pt_regs *regs, uint64_t *addr, +static int mce_find_instr_ea_and_phys(struct pt_regs *regs, uint64_t *addr, uint64_t *phys_addr) { /* @@ -541,7 +547,8 @@ static int mce_handle_derror(struct pt_regs *regs, * kernel/exception-64s.h */ if (get_paca()->in_mce < MAX_MCE_DEPTH) - mce_find_instr_ea_and_pfn(regs, addr, phys_addr); + mce_find_instr_ea_and_phys(regs, addr, + phys_addr); } found = 1; }