[Blackfin] arch: fix bug - trap_tests fails to recover on some tests.

http://blackfin.uclinux.org/gf/project/uclinux-dist/tracker/?action=TrackerItemEdit&tracker_item_id=3719

When the CPLBs get a miss, we do:
  - find a victim in the HW table
  - remove the victim
  - find the replacement in the software table
  - put it into the HW table.

If we can't find a replacement in the software table, we accidently
leave a duplicate in the HW table. This patch ensures that duplicate
is marked as not valid.

What we should do is find the replacement in the software table, before
we find a victim in the HW table - but its too late in the release cycle
to do that much restructuring of this code.

Rather that duplicate code, connect Hardware Errors (irq5) into trap_c,
so user space processes get killed properly.

The rest of irq_panic() can be moved into traps.c (later)

There is still a small corner case that causes problems when a
pheriperal interrupt goes off a single cycle before a user space
hardware error. This causes a kernel panic, rather than the user
space process being killed.

But, this checkin makes things work in 99.9% of the cases, and is a vast
improvement from what is there today (which fails 100% of the time).

Signed-off-by: Robin Getz <robin.getz@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>

1 files changed, 46 insertions, 8 deletions

diff --git a/arch/blackfin/kernel/traps.c b/arch/blackfin/kernel/traps.c
index 21a55ef19cbd..4be5ff0be60f 100644
--- a/arch/blackfin/kernel/traps.c
+++ b/arch/blackfin/kernel/traps.c
@@ -433,6 +433,36 @@ asmlinkage void trap_c(struct pt_regs *fp)
         /* 0x3D - Reserved, Caught by default */
         /* 0x3E - Reserved, Caught by default */
         /* 0x3F - Reserved, Caught by default */
+        case VEC_HWERR:
+                info.si_code = BUS_ADRALN;
+                sig = SIGBUS;
+                switch (fp->seqstat & SEQSTAT_HWERRCAUSE) {
+                /* System MMR Error */
+                case (SEQSTAT_HWERRCAUSE_SYSTEM_MMR):
+                        info.si_code = BUS_ADRALN;
+                        sig = SIGBUS;
+                        printk(KERN_NOTICE HWC_x2(KERN_NOTICE));
+                        break;
+                /* External Memory Addressing Error */
+                case (SEQSTAT_HWERRCAUSE_EXTERN_ADDR):
+                        info.si_code = BUS_ADRERR;
+                        sig = SIGBUS;
+                        printk(KERN_NOTICE HWC_x3(KERN_NOTICE));
+                        break;
+                /* Performance Monitor Overflow */
+                case (SEQSTAT_HWERRCAUSE_PERF_FLOW):
+                        printk(KERN_NOTICE HWC_x12(KERN_NOTICE));
+                        break;
+                /* RAISE 5 instruction */
+                case (SEQSTAT_HWERRCAUSE_RAISE_5):
+                        printk(KERN_NOTICE HWC_x18(KERN_NOTICE));
+                        break;
+                default:        /* Reserved */
+                        printk(KERN_NOTICE HWC_default(KERN_NOTICE));
+                        break;
+                }
+                CHK_DEBUGGER_TRAP();
+                break;
         default:
                 info.si_code = TRAP_ILLTRAP;
                 sig = SIGTRAP;
@@ -447,7 +477,11 @@ asmlinkage void trap_c(struct pt_regs *fp)
         if (sig != SIGTRAP) {
                 unsigned long stack;
                 dump_bfin_process(fp);
-                dump_bfin_mem((void *)fp->retx);
+                /* Is it an interrupt, or an exception? */
+                if (trapnr == VEC_HWERR)
+                        dump_bfin_mem((void *)fp->pc);
+                else
+                        dump_bfin_mem((void *)fp->retx);
                 show_regs(fp);
 
                 /* Print out the trace buffer if it makes sense */
@@ -672,12 +706,11 @@ void dump_bfin_mem(void *retaddr)
                          * context, which should mean an oops is happening
                          */
                         if (oops_in_progress && x >= 0x0040 && x <= 0x0047 && i <= 0)
-                                panic("\n\nWARNING : You should reconfigure"
+                                printk(KERN_EMERG "\n"
+                                        KERN_EMERG "WARNING : You should reconfigure"
                                         " the kernel to turn on\n"
-                                        " 'Hardware error interrupt"
-                                        " debugging'\n"
-                                        " The rest of this error"
-                                        " is meanless\n");
+                                        KERN_EMERG " 'Hardware error interrupt debugging'\n"
+                                        KERN_EMERG " The rest of this error is meanless\n");
 #endif
                         if (i == (unsigned int)retaddr)
                                 printk("[%04x]", x);
@@ -698,6 +731,10 @@ void show_regs(struct pt_regs *fp)
         printk(KERN_NOTICE "\n" KERN_NOTICE "SEQUENCER STATUS:\n");
         printk(KERN_NOTICE " SEQSTAT: %08lx  IPEND: %04lx  SYSCFG: %04lx\n",
                 (long)fp->seqstat, fp->ipend, fp->syscfg);
+        printk(KERN_NOTICE "  HWERRCAUSE: 0x%lx\n",
+                (fp->seqstat & SEQSTAT_HWERRCAUSE) >> 14);
+        printk(KERN_NOTICE "  EXCAUSE   : 0x%lx\n",
+                fp->seqstat & SEQSTAT_EXCAUSE);
 
         decode_address(buf, fp->rete);
         printk(KERN_NOTICE " RETE: %s\n", buf);
@@ -708,9 +745,10 @@ void show_regs(struct pt_regs *fp)
         decode_address(buf, fp->rets);
         printk(KERN_NOTICE " RETS: %s\n", buf);
         decode_address(buf, fp->pc);
-        printk(KERN_NOTICE " PC: %s\n", buf);
+        printk(KERN_NOTICE " PC  : %s\n", buf);
 
-        if ((long)fp->seqstat & SEQSTAT_EXCAUSE) {
+        if (((long)fp->seqstat &  SEQSTAT_EXCAUSE) &&
+            (((long)fp->seqstat & SEQSTAT_EXCAUSE) != VEC_HWERR)) {
                 decode_address(buf, bfin_read_DCPLB_FAULT_ADDR());
                 printk(KERN_NOTICE "DCPLB_FAULT_ADDR: %s\n", buf);
                 decode_address(buf, bfin_read_ICPLB_FAULT_ADDR());