From: Balbir Singh <bsinghar...@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 <bsinghar...@gmail.com>
[ar...@linux.ibm.com: Fixup pseries_do_memory_failure()]
Signed-off-by: Reza Arbab <ar...@linux.ibm.com>
[santosh: return physical address instead of pfn; change commit log]
Signed-off-by: Santosh Sivaraj <sant...@fossix.org>
---
 arch/powerpc/include/asm/mce.h       |  2 +-
 arch/powerpc/kernel/mce_power.c      | 50 ++++++++++++++--------------
 arch/powerpc/platforms/pseries/ras.c |  9 ++---
 3 files changed, 29 insertions(+), 32 deletions(-)

diff --git a/arch/powerpc/include/asm/mce.h b/arch/powerpc/include/asm/mce.h
index a4c6a74ad2fb..f3a6036b6bc0 100644
--- a/arch/powerpc/include/asm/mce.h
+++ b/arch/powerpc/include/asm/mce.h
@@ -209,7 +209,7 @@ extern void release_mce_event(void);
 extern void machine_check_queue_event(void);
 extern void machine_check_print_event_info(struct machine_check_event *evt,
                                           bool user_mode, bool in_guest);
-unsigned long addr_to_pfn(struct pt_regs *regs, unsigned long addr);
+unsigned long addr_to_phys(struct pt_regs *regs, unsigned long addr);
 #ifdef CONFIG_PPC_BOOK3S_64
 void flush_and_reload_slb(void);
 #endif /* CONFIG_PPC_BOOK3S_64 */
diff --git a/arch/powerpc/kernel/mce_power.c b/arch/powerpc/kernel/mce_power.c
index a814d2dfb5b0..bed38a8e2e50 100644
--- a/arch/powerpc/kernel/mce_power.c
+++ b/arch/powerpc/kernel/mce_power.c
@@ -20,13 +20,14 @@
 #include <asm/exception-64s.h>
 
 /*
- * Convert an address related to an mm to a PFN. NOTE: we are in real
- * mode, we could potentially race with page table updates.
+ * Convert an address related to an mm to a physical address.
+ * NOTE: we are in real mode, we could potentially race with page table 
updates.
  */
-unsigned long addr_to_pfn(struct pt_regs *regs, unsigned long addr)
+unsigned long addr_to_phys(struct pt_regs *regs, unsigned long addr)
 {
-       pte_t *ptep;
-       unsigned long flags;
+       pte_t *ptep, pte;
+       unsigned int shift;
+       unsigned long flags, phys_addr;
        struct mm_struct *mm;
 
        if (user_mode(regs))
@@ -35,14 +36,21 @@ 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;
-       return pte_pfn(*ptep);
+
+       pte = *ptep;
+       if (shift > PAGE_SHIFT) {
+               unsigned long rpnmask = (1ul << shift) - PAGE_SIZE;
+
+               pte = __pte(pte_val(pte) | (addr & rpnmask));
+       }
+       phys_addr = pte_pfn(pte) << PAGE_SHIFT;
+
+       return phys_addr;
 }
 
 /* flush SLBs and reload */
@@ -354,18 +362,16 @@ static int mce_find_instr_ea_and_pfn(struct pt_regs 
*regs, uint64_t *addr,
         * faults
         */
        int instr;
-       unsigned long pfn, instr_addr;
+       unsigned long instr_addr;
        struct instruction_op op;
        struct pt_regs tmp = *regs;
 
-       pfn = addr_to_pfn(regs, regs->nip);
-       if (pfn != ULONG_MAX) {
-               instr_addr = (pfn << PAGE_SHIFT) + (regs->nip & ~PAGE_MASK);
+       instr_addr = addr_to_phys(regs, regs->nip) + (regs->nip & ~PAGE_MASK);
+       if (instr_addr != ULONG_MAX) {
                instr = *(unsigned int *)(instr_addr);
                if (!analyse_instr(&op, &tmp, instr)) {
-                       pfn = addr_to_pfn(regs, op.ea);
                        *addr = op.ea;
-                       *phys_addr = (pfn << PAGE_SHIFT);
+                       *phys_addr = addr_to_phys(regs, op.ea);
                        return 0;
                }
                /*
@@ -440,15 +446,9 @@ static int mce_handle_ierror(struct pt_regs *regs,
                        *addr = regs->nip;
                        if (mce_err->sync_error &&
                                table[i].error_type == MCE_ERROR_TYPE_UE) {
-                               unsigned long pfn;
-
-                               if (get_paca()->in_mce < MAX_MCE_DEPTH) {
-                                       pfn = addr_to_pfn(regs, regs->nip);
-                                       if (pfn != ULONG_MAX) {
-                                               *phys_addr =
-                                                       (pfn << PAGE_SHIFT);
-                                       }
-                               }
+                               if (get_paca()->in_mce < MAX_MCE_DEPTH)
+                                       *phys_addr = addr_to_phys(regs,
+                                                                regs->nip);
                        }
                }
                return handled;
diff --git a/arch/powerpc/platforms/pseries/ras.c 
b/arch/powerpc/platforms/pseries/ras.c
index f16fdd0f71f7..5743f6353638 100644
--- a/arch/powerpc/platforms/pseries/ras.c
+++ b/arch/powerpc/platforms/pseries/ras.c
@@ -739,13 +739,10 @@ static void pseries_do_memory_failure(struct pt_regs 
*regs,
        if (mce_log->sub_err_type & UE_LOGICAL_ADDR_PROVIDED) {
                paddr = be64_to_cpu(mce_log->logical_address);
        } else if (mce_log->sub_err_type & UE_EFFECTIVE_ADDR_PROVIDED) {
-               unsigned long pfn;
-
-               pfn = addr_to_pfn(regs,
-                                 be64_to_cpu(mce_log->effective_address));
-               if (pfn == ULONG_MAX)
+               paddr = addr_to_phys(regs,
+                                    be64_to_cpu(mce_log->effective_address));
+               if (paddr == ULONG_MAX)
                        return;
-               paddr = pfn << PAGE_SHIFT;
        } else {
                return;
        }
-- 
2.20.1

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