Blackfin arch: Better error handling of unknown exceptions

Better error handling of unknown exceptions, allows userspace to do a
EXCPT n instruction for a not installed exception handler, and the
kernel doesn't crash (like it use to before this).

Signed-off-by: Robin Getz <rgetz@blackfin.uclinux.org>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

2 files changed, 33 insertions, 15 deletions

diff --git a/arch/blackfin/include/asm/traps.h b/arch/blackfin/include/asm/traps.h
index f0e5f940d9ca..34f7295fb070 100644
--- a/arch/blackfin/include/asm/traps.h
+++ b/arch/blackfin/include/asm/traps.h
@@ -59,6 +59,9 @@
         level "   or a 16-bit register is accessed with a 32-bit instruction.\n"
 #define HWC_x3(level) \
         "External Memory Addressing Error\n"
+#define EXC_0x04(level) \
+        "Unimplmented exception occured\n" \
+        level " - Maybe you forgot to install a custom exception handler?\n"
 #define HWC_x12(level) \
         "Performance Monitor Overflow\n"
 #define HWC_x18(level) \
@@ -84,7 +87,7 @@
         level "   a particular processor implementation.\n"
 #define EXC_0x22(level) \
         "Illegal instruction combination\n" \
-        level " - See section for multi-issue rules in the ADSP-BF53x Blackfin\n" \
+        level " - See section for multi-issue rules in the Blackfin\n" \
         level "   Processor Instruction Set Reference.\n"
 #define EXC_0x23(level) \
         "Data access CPLB protection violation\n" \
diff --git a/arch/blackfin/kernel/traps.c b/arch/blackfin/kernel/traps.c
index 8d561baef896..be5ae7fabc5f 100644
--- a/arch/blackfin/kernel/traps.c
+++ b/arch/blackfin/kernel/traps.c
@@ -301,18 +301,28 @@ asmlinkage void trap_c(struct pt_regs *fp)
                 printk(KERN_NOTICE EXC_0x03(KERN_NOTICE));
                 CHK_DEBUGGER_TRAP_MAYBE();
                 break;
-        /* 0x04 - User Defined, Caught by default */
-        /* 0x05 - User Defined, Caught by default */
-        /* 0x06 - User Defined, Caught by default */
-        /* 0x07 - User Defined, Caught by default */
-        /* 0x08 - User Defined, Caught by default */
-        /* 0x09 - User Defined, Caught by default */
-        /* 0x0A - User Defined, Caught by default */
-        /* 0x0B - User Defined, Caught by default */
-        /* 0x0C - User Defined, Caught by default */
-        /* 0x0D - User Defined, Caught by default */
-        /* 0x0E - User Defined, Caught by default */
-        /* 0x0F - User Defined, Caught by default */
+        /* 0x04 - User Defined */
+        /* 0x05 - User Defined */
+        /* 0x06 - User Defined */
+        /* 0x07 - User Defined */
+        /* 0x08 - User Defined */
+        /* 0x09 - User Defined */
+        /* 0x0A - User Defined */
+        /* 0x0B - User Defined */
+        /* 0x0C - User Defined */
+        /* 0x0D - User Defined */
+        /* 0x0E - User Defined */
+        /* 0x0F - User Defined */
+        /*
+         * If we got here, it is most likely that someone was trying to use a
+         * custom exception handler, and it is not actually installed properly
+         */
+        case VEC_EXCPT04 ... VEC_EXCPT15:
+                info.si_code = ILL_ILLPARAOP;
+                sig = SIGILL;
+                printk(KERN_NOTICE EXC_0x04(KERN_NOTICE));
+                CHK_DEBUGGER_TRAP_MAYBE();
+                break;
         /* 0x10 HW Single step, handled here */
         case VEC_STEP:
                 info.si_code = TRAP_STEP;
@@ -507,9 +517,14 @@ asmlinkage void trap_c(struct pt_regs *fp)
                 }
                 CHK_DEBUGGER_TRAP_MAYBE();
                 break;
+        /*
+         * We should be handling all known exception types above,
+         * if we get here we hit a reserved one, so panic
+         */
         default:
-                info.si_code = TRAP_ILLTRAP;
-                sig = SIGTRAP;
+                oops_in_progress = 1;
+                info.si_code = ILL_ILLPARAOP;
+                sig = SIGILL;
                 printk(KERN_EMERG "Caught Unhandled Exception, code = %08lx\n",
                         (fp->seqstat & SEQSTAT_EXCAUSE));
                 CHK_DEBUGGER_TRAP_MAYBE();