ppc64: iseries soft disable and do_page_fault fixes from Ben Herrenschmidt

arch/ppc64/kernel/head.S

@@ -40,6 +40,15 @@
 #define DO_SOFT_DISABLE
 #endif
 
+/* copy saved SOFTE bit or EE bit from saved MSR depending
+ * if we are doing soft-disable or not
+ */
+#ifdef DO_SOFT_DISABLE
+#define DO_COPY_EE()	ld	r20,SOFTE(r1)
+#else
+#define DO_COPY_EE()	rldicl	r20,r23,49,63
+#endif
+
 /*
  * hcall interface to pSeries LPAR
  */
@@ -618,11 +627,7 @@ stab_bolted_user_return:
 	ld      r4,_DAR(r1)
 	ld      r5,_DSISR(r1)
 	addi	r3,r1,STACK_FRAME_OVERHEAD
-#ifdef DO_SOFT_DISABLE
-	ld	r20,SOFTE(r1)		/* Copy saved SOFTE bit */
-#else
-	rldicl	r20,r23,49,63   	/* copy EE bit from saved MSR */
-#endif
+	DO_COPY_EE()
 	li	r6,0x300
 	bl      .save_remaining_regs
 	bl      .do_page_fault
@@ -644,12 +649,9 @@ DataAccessSLB_common:
 	or.	r3,r3,r3		/* Check return code */
 	beq     fast_exception_return   /* Return if we succeeded */
 	addi	r3,r1,STACK_FRAME_OVERHEAD
-#ifdef DO_SOFT_DISABLE
-	ld	r20,SOFTE(r1)
-#else
-	rldicl	r20,r23,49,63   	/* copy EE bit from saved MSR */
-#endif
+	DO_COPY_EE()
 	li	r6,0x380
+	li	r5,0
 	bl      .save_remaining_regs
 	bl      .do_page_fault
 	b       .ret_from_except
@@ -670,13 +672,9 @@ InstructionAccess_common:
 	bl	.do_hash_page_ISI	/* Try to handle as hpte fault */
 1:
 	mr	r4,r22
-	mr	r5,r23
+	rlwinm	r5,r23,0,4,4		/* We only care about PR in error_code */
 	addi	r3,r1,STACK_FRAME_OVERHEAD
-#ifdef DO_SOFT_DISABLE
-	ld	r20,SOFTE(r1)
-#else
-	rldicl	r20,r23,49,63   	/* copy EE bit from saved MSR */
-#endif
+	DO_COPY_EE()
 	li	r6,0x400
 	bl      .save_remaining_regs
 	bl      .do_page_fault
@@ -692,12 +690,9 @@ InstructionAccessSLB_common:
 	beq+	fast_exception_return   /* Return if we succeeded */
 
 	addi	r3,r1,STACK_FRAME_OVERHEAD
-#ifdef DO_SOFT_DISABLE
-	ld	r20,SOFTE(r1)
-#else
-	rldicl	r20,r23,49,63   	/* copy EE bit from saved MSR */
-#endif
+	DO_COPY_EE()
 	li	r6,0x480
+	li	r5,0
 	bl      .save_remaining_regs
 	bl      .do_page_fault
 	b       .ret_from_except
@@ -769,11 +764,7 @@ HardwareInterrupt_entry:
 Alignment_common:
 	EXCEPTION_PROLOG_COMMON
 	addi	r3,r1,STACK_FRAME_OVERHEAD
-#ifdef DO_SOFT_DISABLE
-	ld	r20,SOFTE(r1)
-#else
-	rldicl	r20,r23,49,63   	/* copy EE bit from saved MSR */
-#endif
+	DO_COPY_EE()
 	li	r6,0x600
 	bl      .save_remaining_regs
 	bl      .AlignmentException
@@ -783,11 +774,7 @@ Alignment_common:
 ProgramCheck_common:
 	EXCEPTION_PROLOG_COMMON
 	addi	r3,r1,STACK_FRAME_OVERHEAD
-#ifdef DO_SOFT_DISABLE
-	ld	r20,SOFTE(r1)
-#else
-	rldicl	r20,r23,49,63   	/* copy EE bit from saved MSR */
-#endif
+	DO_COPY_EE()
 	li	r6,0x700
 	bl      .save_remaining_regs
 	bl      .ProgramCheckException
@@ -798,11 +785,7 @@ FPUnavailable_common:
 	EXCEPTION_PROLOG_COMMON
 	bne	.load_up_fpu		/* if from user, just load it up */
 	addi	r3,r1,STACK_FRAME_OVERHEAD
-#ifdef DO_SOFT_DISABLE
-	ld	r20,SOFTE(r1)
-#else
-	rldicl	r20,r23,49,63   	/* copy EE bit from saved MSR */
-#endif
+	DO_COPY_EE()
 	li	r6,0x800
 	bl      .save_remaining_regs
 	bl      .KernelFPUnavailableException
@@ -818,11 +801,7 @@ SystemCall_common:
 	beq+	HardwareInterrupt_entry
 1:
 #endif
-#ifdef DO_SOFT_DISABLE
-	ld	r20,SOFTE(r1)
-#else
-	rldicl	r20,r23,49,63   	/* copy EE bit from saved MSR */
-#endif
+	DO_COPY_EE()
 	li	r6,0xC00
 	bl      .save_remaining_regs
 	bl      .DoSyscall

arch/ppc64/mm/fault.c

@@ -46,8 +46,10 @@ int debugger_kernel_faults = 1;
 void bad_page_fault(struct pt_regs *, unsigned long, int);
 
 /*
- * For 600- and 800-family processors, the error_code parameter is DSISR
- * for a data fault, SRR1 for an instruction fault.
+ * The error_code parameter is
+ *  - DSISR for a non-SLB data access fault,
+ *  - SRR1 & 0x08000000 for a non-SLB instruction access fault
+ *  - 0 any SLB fault.
  */
 void do_page_fault(struct pt_regs *regs, unsigned long address,
 		   unsigned long error_code)
@@ -58,17 +60,6 @@ void do_page_fault(struct pt_regs *regs, unsigned long address,
 	unsigned long code = SEGV_MAPERR;
 	unsigned long is_write = error_code & 0x02000000;
 
-	/*
-	 * Fortunately the bit assignments in SRR1 for an instruction
-	 * fault and DSISR for a data fault are mostly the same for the
-	 * bits we are interested in.  But there are some bits which
-	 * indicate errors in DSISR but can validly be set in SRR1.
-	 */
-	if (regs->trap == 0x400)
-		error_code &= 0x48200000;
-	else if (regs->trap != 0x300) /* ensure error_code is 0 on SLB miss */
-		error_code = 0;
-
 #ifdef CONFIG_DEBUG_KERNEL
 	if (debugger_fault_handler && (regs->trap == 0x300 ||
 				       regs->trap == 0x380)) {