[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, 30 insertions, 10 deletions

diff --git a/arch/blackfin/mach-common/interrupt.S b/arch/blackfin/mach-common/interrupt.S
index 4de376418a18..f983ac7ea352 100644
--- a/arch/blackfin/mach-common/interrupt.S
+++ b/arch/blackfin/mach-common/interrupt.S
@@ -34,9 +34,13 @@
 #include <asm/entry.h>
 #include <asm/asm-offsets.h>
 #include <asm/trace.h>
+#include <asm/traps.h>
+#include <asm/thread_info.h>
 
 #include <asm/mach-common/context.S>
 
+.extern _ret_from_exception
+
 #ifdef CONFIG_I_ENTRY_L1
 .section .l1.text
 #else
@@ -134,10 +138,11 @@ __common_int_entry:
 
 /* interrupt routine for ivhw - 5 */
 ENTRY(_evt_ivhw)
-        SAVE_CONTEXT
+        SAVE_ALL_SYS
 #ifdef CONFIG_FRAME_POINTER
         fp = 0;
 #endif
+
 #if ANOMALY_05000283
         cc = r7 == r7;
         p5.h = 0xffc0;
@@ -147,13 +152,8 @@ ENTRY(_evt_ivhw)
 1:
 #endif
 
-        trace_buffer_stop(p0, r0);
-
-        r0 = IRQ_HWERR;
-        r1 = sp;
-
 #ifdef CONFIG_HARDWARE_PM
-        r7 = SEQSTAT;
+        r7 = [sp + PT_SEQSTAT];
         r7 = r7 >>> 0xe;
         r6 = 0x1F;
         r7 = r7 & r6;
@@ -161,11 +161,29 @@ ENTRY(_evt_ivhw)
         cc = r7 == r5;
         if cc jump .Lcall_do_ovf; /* deal with performance counter overflow */
 #endif
-
+        # We are going to dump something out, so make sure we print IPEND properly
+        p2.l = lo(IPEND);
+        p2.h = hi(IPEND);
+        r0 = [p2];
+        [sp + PT_IPEND] = r0;
+
+        /* set the EXCAUSE to HWERR for trap_c */
+        r0 = [sp + PT_SEQSTAT];
+        R1.L = LO(VEC_HWERR);
+        R1.H = HI(VEC_HWERR);
+        R0 = R0 | R1;
+        [sp + PT_SEQSTAT] = R0;
+
+        r0 = sp;        /* stack frame pt_regs pointer argument ==> r0 */
         SP += -12;
-        call _irq_panic;
+        call _trap_c;
         SP += 12;
+
+        call _ret_from_exception;
+.Lcommon_restore_all_sys:
+        RESTORE_ALL_SYS
         rti;
+
 #ifdef CONFIG_HARDWARE_PM
 .Lcall_do_ovf:
 
@@ -173,9 +191,11 @@ ENTRY(_evt_ivhw)
         call _pm_overflow;
         SP += 12;
 
-        jump .Lcommon_restore_context;
+        jump .Lcommon_restore_all_sys;
 #endif
 
+ENDPROC(_evt_ivhw)
+
 /* Interrupt routine for evt2 (NMI).
  * We don't actually use this, so just return.
  * For inner circle type details, please see: