1 files changed, 23 insertions, 12 deletions

diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index 6a12d1bb6e09..6c013f544146 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -49,6 +49,7 @@
 #define VM_FAULT_BADCONTEXT     0x010000
 #define VM_FAULT_BADMAP         0x020000
 #define VM_FAULT_BADACCESS      0x040000
+#define VM_FAULT_SIGNAL 0x080000
 
 static unsigned long store_indication;
 
@@ -110,7 +111,7 @@ static inline int user_space_fault(unsigned long trans_exc_code)
         if (trans_exc_code == 2)
                 /* Access via secondary space, set_fs setting decides */
                 return current->thread.mm_segment.ar4;
-        if (user_mode == HOME_SPACE_MODE)
+        if (addressing_mode == HOME_SPACE_MODE)
                 /* User space if the access has been done via home space. */
                 return trans_exc_code == 3;
         /*
@@ -219,7 +220,7 @@ static noinline void do_fault_error(struct pt_regs *regs, int fault)
         case VM_FAULT_BADACCESS:
         case VM_FAULT_BADMAP:
                 /* Bad memory access. Check if it is kernel or user space. */
-                if (regs->psw.mask & PSW_MASK_PSTATE) {
+                if (user_mode(regs)) {
                         /* User mode accesses just cause a SIGSEGV */
                         si_code = (fault == VM_FAULT_BADMAP) ?
                                 SEGV_MAPERR : SEGV_ACCERR;
@@ -229,15 +230,19 @@ static noinline void do_fault_error(struct pt_regs *regs, int fault)
         case VM_FAULT_BADCONTEXT:
                 do_no_context(regs);
                 break;
+        case VM_FAULT_SIGNAL:
+                if (!user_mode(regs))
+                        do_no_context(regs);
+                break;
         default: /* fault & VM_FAULT_ERROR */
                 if (fault & VM_FAULT_OOM) {
-                        if (!(regs->psw.mask & PSW_MASK_PSTATE))
+                        if (!user_mode(regs))
                                 do_no_context(regs);
                         else
                                 pagefault_out_of_memory();
                 } else if (fault & VM_FAULT_SIGBUS) {
                         /* Kernel mode? Handle exceptions or die */
-                        if (!(regs->psw.mask & PSW_MASK_PSTATE))
+                        if (!user_mode(regs))
                                 do_no_context(regs);
                         else
                                 do_sigbus(regs);
@@ -286,7 +291,7 @@ static inline int do_exception(struct pt_regs *regs, int access)
 
         address = trans_exc_code & __FAIL_ADDR_MASK;
         perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
-        flags = FAULT_FLAG_ALLOW_RETRY;
+        flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
         if (access == VM_WRITE || (trans_exc_code & store_indication) == 0x400)
                 flags |= FAULT_FLAG_WRITE;
         down_read(&mm->mmap_sem);
@@ -335,6 +340,11 @@ retry:
          * the fault.
          */
         fault = handle_mm_fault(mm, vma, address, flags);
+        /* No reason to continue if interrupted by SIGKILL. */
+        if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) {
+                fault = VM_FAULT_SIGNAL;
+                goto out;
+        }
         if (unlikely(fault & VM_FAULT_ERROR))
                 goto out_up;
 
@@ -426,7 +436,7 @@ void __kprobes do_asce_exception(struct pt_regs *regs)
         }
 
         /* User mode accesses just cause a SIGSEGV */
-        if (regs->psw.mask & PSW_MASK_PSTATE) {
+        if (user_mode(regs)) {
                 do_sigsegv(regs, SEGV_MAPERR);
                 return;
         }
@@ -441,6 +451,7 @@ int __handle_fault(unsigned long uaddr, unsigned long pgm_int_code, int write)
         struct pt_regs regs;
         int access, fault;
 
+        /* Emulate a uaccess fault from kernel mode. */
         regs.psw.mask = psw_kernel_bits | PSW_MASK_DAT | PSW_MASK_MCHECK;
         if (!irqs_disabled())
                 regs.psw.mask |= PSW_MASK_IO | PSW_MASK_EXT;
@@ -450,12 +461,12 @@ int __handle_fault(unsigned long uaddr, unsigned long pgm_int_code, int write)
         regs.int_parm_long = (uaddr & PAGE_MASK) | 2;
         access = write ? VM_WRITE : VM_READ;
         fault = do_exception(&regs, access);
-        if (unlikely(fault)) {
-                if (fault & VM_FAULT_OOM)
-                        return -EFAULT;
-                else if (fault & VM_FAULT_SIGBUS)
-                        do_sigbus(&regs);
-        }
+        /*
+         * Since the fault happened in kernel mode while performing a uaccess
+         * all we need to do now is emulating a fixup in case "fault" is not
+         * zero.
+         * For the calling uaccess functions this results always in -EFAULT.
+         */
         return fault ? -EFAULT : 0;
 }