Blackfin: improve double fault debug handling
Since the hardware only provides reporting for the last exception handled,
and the values are valid only when executing the exception handler, we
need to save the context for reporting at a later point. While we do this
for one exception, it doesn't work properly when handling a second one as
the original exception is clobbered by the double fault. So when double
fault debugging is enabled, create a dedicated shadow of these values and
save/restore out of there. Now the crash report properly displays the
first exception as well as the second one.
Signed-off-by: Graf Yang <graf.yang@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/arch/blackfin/mach-common/entry.S b/arch/blackfin/mach-common/entry.S
index cbc5b6d..4e8e3fe 100644
--- a/arch/blackfin/mach-common/entry.S
+++ b/arch/blackfin/mach-common/entry.S
@@ -326,8 +326,6 @@
[p4] = r7;
csync;
-#ifndef CONFIG_DEBUG_DOUBLEFAULT
-
/*
* Save these registers, as they are only valid in exception context
* (where we are now - as soon as we defer to IRQ5, they can change)
@@ -347,7 +345,10 @@
r6 = retx;
[p5 + PDA_RETX] = r6;
-#endif
+
+ r6 = SEQSTAT;
+ [p5 + PDA_SEQSTAT] = r6;
+
/* Save the state of single stepping */
r6 = SYSCFG;
[p5 + PDA_SYSCFG] = r6;
@@ -444,6 +445,9 @@
r6 = [p5 + PDA_SYSCFG];
[sp + PT_SYSCFG] = r6;
+ r6 = [p5 + PDA_SEQSTAT]; /* Read back seqstat */
+ [sp + PT_SEQSTAT] = r6;
+
/* Restore the hardware error vector. */
r7.h = _evt_ivhw;
r7.l = _evt_ivhw;
@@ -496,7 +500,7 @@
*/
EX_SCRATCH_REG = sp;
GET_PDA_SAFE(sp);
- sp = [sp + PDA_EXSTACK]
+ sp = [sp + PDA_EXSTACK];
/* Try to deal with syscalls quickly. */
[--sp] = ASTAT;
[--sp] = (R7:6,P5:4);
@@ -532,18 +536,18 @@
p4.l = lo(DCPLB_FAULT_ADDR);
p4.h = hi(DCPLB_FAULT_ADDR);
r7 = [p4];
- [p5 + PDA_DCPLB] = r7;
+ [p5 + PDA_DF_DCPLB] = r7;
p4.l = lo(ICPLB_FAULT_ADDR);
p4.h = hi(ICPLB_FAULT_ADDR);
r7 = [p4];
- [p5 + PDA_ICPLB] = r7;
+ [p5 + PDA_DF_ICPLB] = r7;
- r6 = retx;
- [p5 + PDA_RETX] = r6;
+ r7 = retx;
+ [p5 + PDA_DF_RETX] = r7;
r7 = SEQSTAT; /* reason code is in bit 5:0 */
- [p5 + PDA_SEQSTAT] = r7;
+ [p5 + PDA_DF_SEQSTAT] = r7;
#else
r7 = SEQSTAT; /* reason code is in bit 5:0 */
#endif