Blackfin arch: ensure we work around ANOMALY_05000261 for null pointers

 We currently do not. Also make it easier to handle cplb violations - in traps.c
Signed-off-by: Robin Getz <robin.getz@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>

arch/blackfin/kernel/traps.c

@@ -311,11 +311,10 @@ asmlinkage void trap_c(struct pt_regs *fp)
 		printk(KERN_NOTICE EXC_0x22);
 		CHK_DEBUGGER_TRAP();
 		break;
-	/* 0x23 - Data CPLB Protection Violation,
-		 normal case is handled in _cplb_hdr */
+	/* 0x23 - Data CPLB protection violation, handled here */
 	case VEC_CPLB_VL:
 		info.si_code = ILL_CPLB_VI;
-		sig = SIGILL;
+		sig = SIGBUS;
 		printk(KERN_NOTICE EXC_0x23);
 		CHK_DEBUGGER_TRAP();
 		break;
@@ -382,11 +381,10 @@ asmlinkage void trap_c(struct pt_regs *fp)
 		printk(KERN_NOTICE EXC_0x2A);
 		CHK_DEBUGGER_TRAP();
 		break;
-	/* 0x2B - Instruction CPLB protection Violation,
-		handled in _cplb_hdr */
+	/* 0x2B - Instruction CPLB protection violation, handled here */
 	case VEC_CPLB_I_VL:
 		info.si_code = ILL_CPLB_VI;
-		sig = SIGILL;
+		sig = SIGBUS;
 		printk(KERN_NOTICE EXC_0x2B);
 		CHK_DEBUGGER_TRAP();
 		break;

arch/blackfin/mach-common/entry.S

@@ -71,13 +71,18 @@ ENDPROC(_safe_speculative_execution)
  * This one does not lower the level to IRQ5, and thus can be used to
  * patch up CPLB misses on the kernel stack.
  */
-ENTRY(_ex_dcplb)
 #if ANOMALY_05000261
+#define _ex_dviol _ex_workaround_261
+#define _ex_dmiss _ex_workaround_261
+#define _ex_dmult _ex_workaround_261
+
+ENTRY(_ex_workaround_261)
 	/*
 	 * Work around an anomaly: if we see a new DCPLB fault, return
 	 * without doing anything.  Then, if we get the same fault again,
 	 * handle it.
 	 */
+	P4 = R7;	/* Store EXCAUSE */
 	p5.l = _last_cplb_fault_retx;
 	p5.h = _last_cplb_fault_retx;
 	r7 = [p5];
@@ -86,10 +91,24 @@ ENTRY(_ex_dcplb)
 	cc = r6 == r7;
 	if !cc jump _return_from_exception;
 	/* fall through */
+	R7 = P4;
+	R6 = 0x26;	/* Data CPLB Miss */
+	cc = R6 == R7;
+	if cc jump _ex_dcplb_miss (BP);
+	/* Handle 0x23 Data CPLB Protection Violation
+	 * and Data CPLB Multiple Hits - Linux Trap Zero
+	 */
+	jump _ex_trap_c;
+ENDPROC(_ex_workaround_261)
+
+#else
+#define _ex_dviol _ex_trap_c
+#define _ex_dmiss _ex_dcplb_miss
+#define _ex_dmult _ex_trap_c
 #endif
-ENDPROC(_ex_dcplb)
 
-ENTRY(_ex_icplb)
+ENTRY(_ex_dcplb_miss)
+ENTRY(_ex_icplb_miss)
 	(R7:6,P5:4) = [sp++];
 	ASTAT = [sp++];
 	SAVE_ALL_SYS
@@ -98,7 +117,7 @@ ENTRY(_ex_icplb)
 	RESTORE_ALL_SYS
 	SP = EX_SCRATCH_REG;
 	rtx;
-ENDPROC(_ex_icplb)
+ENDPROC(_ex_icplb_miss)
 
 ENTRY(_ex_syscall)
 	DEBUG_START_HWTRACE(p5, r7)
@@ -908,6 +927,7 @@ ENDPROC(_early_trap)
 #else
 .data
 #endif
+
 ENTRY(_ex_table)
 	/* entry for each EXCAUSE[5:0]
 	 * This table must be in sync with the table in ./kernel/traps.c
@@ -952,16 +972,16 @@ ENTRY(_ex_table)
 	.long _ex_trap_c        /* 0x20 - Reserved */
 	.long _ex_trap_c        /* 0x21 - Undefined Instruction */
 	.long _ex_trap_c        /* 0x22 - Illegal Instruction Combination */
-	.long _ex_dcplb         /* 0x23 - Data CPLB Protection Violation */
+	.long _ex_dviol         /* 0x23 - Data CPLB Protection Violation */
 	.long _ex_trap_c        /* 0x24 - Data access misaligned */
 	.long _ex_trap_c        /* 0x25 - Unrecoverable Event */
-	.long _ex_dcplb         /* 0x26 - Data CPLB Miss */
-	.long _ex_trap_c        /* 0x27 - Data CPLB Multiple Hits - Linux Trap Zero */
+	.long _ex_dmiss         /* 0x26 - Data CPLB Miss */
+	.long _ex_dmult         /* 0x27 - Data CPLB Multiple Hits - Linux Trap Zero */
 	.long _ex_trap_c        /* 0x28 - Emulation Watchpoint */
 	.long _ex_trap_c        /* 0x29 - Instruction fetch access error (535 only) */
 	.long _ex_trap_c        /* 0x2A - Instruction fetch misaligned */
-	.long _ex_icplb         /* 0x2B - Instruction CPLB protection Violation */
-	.long _ex_icplb         /* 0x2C - Instruction CPLB miss */
+	.long _ex_trap_c        /* 0x2B - Instruction CPLB protection Violation */
+	.long _ex_icplb_miss    /* 0x2C - Instruction CPLB miss */
 	.long _ex_trap_c        /* 0x2D - Instruction CPLB Multiple Hits */
 	.long _ex_trap_c        /* 0x2E - Illegal use of Supervisor Resource */
 	.long _ex_trap_c        /* 0x2E - Illegal use of Supervisor Resource */