[PATCH 1/2] powerpc: Add VM_FAULT_HWPOISON handling to powerpc page fault handler

[Anton Blanchard]

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 <an...@samba.org>
---
 arch/powerpc/mm/fault.c | 36 +++++++++++++++++++++---------------
 1 file changed, 21 insertions(+), 15 deletions(-)

diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 51ab9e7..c3728c1 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -114,22 +114,31 @@ 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;
 
        up_read(&current->mm->mmap_sem);
 
-       if (user_mode(regs)) {
-               current->thread.trap_nr = BUS_ADRERR;
-               info.si_signo = SIGBUS;
-               info.si_errno = 0;
-               info.si_code = BUS_ADRERR;
-               info.si_addr = (void __user *)address;
-               force_sig_info(SIGBUS, &info, current);
-               return MM_FAULT_RETURN;
+       if (!user_mode(regs))
+               return MM_FAULT_ERR(SIGBUS);
+
+       current->thread.trap_nr = BUS_ADRERR;
+       info.si_signo = SIGBUS;
+       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;
        }
-       return MM_FAULT_ERR(SIGBUS);
+#endif
+       force_sig_info(SIGBUS, &info, current);
+       return MM_FAULT_RETURN;
 }
 
 static int mm_fault_error(struct pt_regs *regs, unsigned long addr, int fault)
@@ -170,11 +179,8 @@ 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();
-- 
1.9.1

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