powerpc: Add VM_FAULT_HWPOISON handling to powerpc page fault handler

do_page_fault was missing knowledge of HWPOISON, and we would oops
if userspace tried to access a poisoned page:

kernel BUG at arch/powerpc/mm/fault.c:180!

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 11 insertions, 6 deletions

diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index abc8c816a326..588b6ccc0569 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -114,7 +114,8 @@ static int store_updates_sp(struct pt_regs *regs)
 #define MM_FAULT_CONTINUE       -1
 #define MM_FAULT_ERR(sig)       (sig)
 
-static int do_sigbus(struct pt_regs *regs, unsigned long address)
+static int do_sigbus(struct pt_regs *regs, unsigned long address,
+                     unsigned int fault)
 {
         siginfo_t info;
 
@@ -128,6 +129,13 @@ static int do_sigbus(struct pt_regs *regs, unsigned long address)
         info.si_errno = 0;
         info.si_code = BUS_ADRERR;
         info.si_addr = (void __user *)address;
+#ifdef CONFIG_MEMORY_FAILURE
+        if (fault & (VM_FAULT_HWPOISON|VM_FAULT_HWPOISON_LARGE)) {
+                pr_err("MCE: Killing %s:%d due to hardware memory corruption fault at %lx\n",
+                        current->comm, current->pid, address);
+                info.si_code = BUS_MCEERR_AR;
+        }
+#endif
         force_sig_info(SIGBUS, &info, current);
         return MM_FAULT_RETURN;
 }
@@ -170,11 +178,8 @@ static int mm_fault_error(struct pt_regs *regs, unsigned long addr, int fault)
                 return MM_FAULT_RETURN;
         }
 
-        /* Bus error. x86 handles HWPOISON here, we'll add this if/when
-         * we support the feature in HW
-         */
-        if (fault & VM_FAULT_SIGBUS)
-                return do_sigbus(regs, addr);
+        if (fault & (VM_FAULT_SIGBUS|VM_FAULT_HWPOISON|VM_FAULT_HWPOISON_LARGE))
+                return do_sigbus(regs, addr, fault);
 
         /* We don't understand the fault code, this is fatal */
         BUG();