Blackfin arch: add supporting for double fault debug handling
Signed-off-by: Robin Getz <rgetz@blackfin.uclinux.org>
Signed-off-by: Mike Frysinger <vapier.adi@gmail.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
diff --git a/arch/blackfin/mach-common/entry.S b/arch/blackfin/mach-common/entry.S
index 847c172..90c7397 100644
--- a/arch/blackfin/mach-common/entry.S
+++ b/arch/blackfin/mach-common/entry.S
@@ -129,6 +129,18 @@
#else
call __cplb_hdr;
#endif
+
+#ifdef CONFIG_DEBUG_DOUBLEFAULT
+ /* While we were processing this, did we double fault? */
+ r7 = SEQSTAT; /* reason code is in bit 5:0 */
+ r6.l = lo(SEQSTAT_EXCAUSE);
+ r6.h = hi(SEQSTAT_EXCAUSE);
+ r7 = r7 & r6;
+ r6 = 0x25;
+ CC = R7 == R6;
+ if CC JUMP _double_fault;
+#endif
+
DEBUG_HWTRACE_RESTORE(p5, r7)
RESTORE_ALL_SYS
SP = EX_SCRATCH_REG;
@@ -136,11 +148,8 @@
ENDPROC(_ex_icplb_miss)
ENTRY(_ex_syscall)
- (R7:6,P5:4) = [sp++];
- ASTAT = [sp++];
raise 15; /* invoked by TRAP #0, for sys call */
- sp = EX_SCRATCH_REG;
- rtx
+ jump.s _bfin_return_from_exception;
ENDPROC(_ex_syscall)
ENTRY(_ex_soft_bp)
@@ -250,6 +259,29 @@
R7=LC1;
LC1=R7;
#endif
+
+#ifdef CONFIG_DEBUG_DOUBLEFAULT
+ /* While we were processing the current exception,
+ * did we cause another, and double fault?
+ */
+ r7 = SEQSTAT; /* reason code is in bit 5:0 */
+ r6.l = lo(SEQSTAT_EXCAUSE);
+ r6.h = hi(SEQSTAT_EXCAUSE);
+ r7 = r7 & r6;
+ r6 = 0x25;
+ CC = R7 == R6;
+ if CC JUMP _double_fault;
+
+ /* Did we cause a HW error? */
+ p5.l = lo(ILAT);
+ p5.h = hi(ILAT);
+ r6 = [p5];
+ r7 = 0x20; /* Did I just cause anther HW error? */
+ r7 = r7 & r1;
+ CC = R7 == R6;
+ if CC JUMP _double_fault;
+#endif
+
(R7:6,P5:4) = [sp++];
ASTAT = [sp++];
sp = EX_SCRATCH_REG;
@@ -292,6 +324,14 @@
[p4] = p5;
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)
+ * DCPLB_STATUS and ICPLB_STATUS are also only valid in EVT3,
+ * but they are not very interesting, so don't save them
+ */
+
p4.l = lo(DCPLB_FAULT_ADDR);
p4.h = hi(DCPLB_FAULT_ADDR);
r7 = [p4];
@@ -304,12 +344,11 @@
p5.l = _saved_icplb_fault_addr;
[p5] = r7;
- p4.l = _excpt_saved_stuff;
- p4.h = _excpt_saved_stuff;
-
r6 = retx;
+ p4.l = _saved_retx;
+ p4.h = _saved_retx;
[p4] = r6;
-
+#endif
r6 = SYSCFG;
[p4 + 4] = r6;
BITCLR(r6, 0);
@@ -327,59 +366,56 @@
r6 = 0x3f;
sti r6;
- (R7:6,P5:4) = [sp++];
- ASTAT = [sp++];
- SP = EX_SCRATCH_REG;
raise 5;
- rtx;
+ jump.s _bfin_return_from_exception;
ENDPROC(_ex_trap_c)
/* We just realized we got an exception, while we were processing a different
* exception. This is a unrecoverable event, so crash
*/
ENTRY(_double_fault)
- /* Turn caches & protection off, to ensure we don't get any more
- * double exceptions
- */
+ /* Turn caches & protection off, to ensure we don't get any more
+ * double exceptions
+ */
- P4.L = LO(IMEM_CONTROL);
- P4.H = HI(IMEM_CONTROL);
+ P4.L = LO(IMEM_CONTROL);
+ P4.H = HI(IMEM_CONTROL);
- R5 = [P4]; /* Control Register*/
- BITCLR(R5,ENICPLB_P);
- SSYNC; /* SSYNC required before writing to IMEM_CONTROL. */
- .align 8;
- [P4] = R5;
- SSYNC;
+ R5 = [P4]; /* Control Register*/
+ BITCLR(R5,ENICPLB_P);
+ SSYNC; /* SSYNC required before writing to IMEM_CONTROL. */
+ .align 8;
+ [P4] = R5;
+ SSYNC;
- P4.L = LO(DMEM_CONTROL);
- P4.H = HI(DMEM_CONTROL);
- R5 = [P4];
- BITCLR(R5,ENDCPLB_P);
- SSYNC; /* SSYNC required before writing to DMEM_CONTROL. */
- .align 8;
- [P4] = R5;
- SSYNC;
+ P4.L = LO(DMEM_CONTROL);
+ P4.H = HI(DMEM_CONTROL);
+ R5 = [P4];
+ BITCLR(R5,ENDCPLB_P);
+ SSYNC; /* SSYNC required before writing to DMEM_CONTROL. */
+ .align 8;
+ [P4] = R5;
+ SSYNC;
- /* Fix up the stack */
- (R7:6,P5:4) = [sp++];
- ASTAT = [sp++];
- SP = EX_SCRATCH_REG;
+ /* Fix up the stack */
+ (R7:6,P5:4) = [sp++];
+ ASTAT = [sp++];
+ SP = EX_SCRATCH_REG;
- /* We should be out of the exception stack, and back down into
- * kernel or user space stack
- */
- SAVE_ALL_SYS
+ /* We should be out of the exception stack, and back down into
+ * kernel or user space stack
+ */
+ SAVE_ALL_SYS
/* The dumping functions expect the return address in the RETI
* slot. */
r6 = retx;
[sp + PT_PC] = r6;
- r0 = sp; /* stack frame pt_regs pointer argument ==> r0 */
- SP += -12;
- call _double_fault_c;
- SP += 12;
+ r0 = sp; /* stack frame pt_regs pointer argument ==> r0 */
+ SP += -12;
+ call _double_fault_c;
+ SP += 12;
.L_double_fault_panic:
JUMP .L_double_fault_panic
@@ -388,8 +424,8 @@
ENTRY(_exception_to_level5)
SAVE_ALL_SYS
- p4.l = _excpt_saved_stuff;
- p4.h = _excpt_saved_stuff;
+ p4.l = _saved_retx;
+ p4.h = _saved_retx;
r6 = [p4];
[sp + PT_PC] = r6;
@@ -420,6 +456,17 @@
call _trap_c;
SP += 12;
+#ifdef CONFIG_DEBUG_DOUBLEFAULT
+ /* Grab ILAT */
+ p2.l = lo(ILAT);
+ p2.h = hi(ILAT);
+ r0 = [p2];
+ r1 = 0x20; /* Did I just cause anther HW error? */
+ r0 = r0 & r1;
+ CC = R0 == R1;
+ if CC JUMP _double_fault;
+#endif
+
call _ret_from_exception;
RESTORE_ALL_SYS
rti;
@@ -436,7 +483,39 @@
/* Try to deal with syscalls quickly. */
[--sp] = ASTAT;
[--sp] = (R7:6,P5:4);
+
+#ifdef 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)
+ * DCPLB_STATUS and ICPLB_STATUS are also only valid in EVT3,
+ * but they are not very interesting, so don't save them
+ */
+
+ p4.l = lo(DCPLB_FAULT_ADDR);
+ p4.h = hi(DCPLB_FAULT_ADDR);
+ r7 = [p4];
+ p5.h = _saved_dcplb_fault_addr;
+ p5.l = _saved_dcplb_fault_addr;
+ [p5] = r7;
+
+ r7 = [p4 + (ICPLB_FAULT_ADDR - DCPLB_FAULT_ADDR)];
+ p5.h = _saved_icplb_fault_addr;
+ p5.l = _saved_icplb_fault_addr;
+ [p5] = r7;
+
+ p4.l = _saved_retx;
+ p4.h = _saved_retx;
+ r6 = retx;
+ [p4] = r6;
+
r7 = SEQSTAT; /* reason code is in bit 5:0 */
+ p4.l = _saved_seqstat;
+ p4.h = _saved_seqstat;
+ [p4] = r7;
+#else
+ r7 = SEQSTAT; /* reason code is in bit 5:0 */
+#endif
r6.l = lo(SEQSTAT_EXCAUSE);
r6.h = hi(SEQSTAT_EXCAUSE);
r7 = r7 & r6;
@@ -1432,15 +1511,7 @@
.rept NR_syscalls-(.-_sys_call_table)/4
.long _sys_ni_syscall
.endr
-
- /*
- * Used to save the real RETX, IMASK and SYSCFG when temporarily
- * storing safe values across the transition from exception to IRQ5.
- */
-_excpt_saved_stuff:
- .long 0;
- .long 0;
- .long 0;
+END(_sys_call_table)
_exception_stack:
.rept 1024
diff --git a/arch/blackfin/mach-common/head.S b/arch/blackfin/mach-common/head.S
index 191b4e9..7cb21cf 100644
--- a/arch/blackfin/mach-common/head.S
+++ b/arch/blackfin/mach-common/head.S
@@ -90,12 +90,46 @@
[p0] = R0;
SSYNC;
- /* Save RETX, in case of doublefault */
- p0.l = ___retx;
- p0.h = ___retx;
+ /* in case of double faults, save a few things */
+ p0.l = _init_retx;
+ p0.h = _init_retx;
R0 = RETX;
[P0] = R0;
+#ifdef CONFIG_DEBUG_DOUBLEFAULT
+ /* Only save these if we are storing them,
+ * This happens here, since L1 gets clobbered
+ * below
+ */
+ p0.l = _saved_retx;
+ p0.h = _saved_retx;
+ p1.l = _init_saved_retx;
+ p1.h = _init_saved_retx;
+ r0 = [p0];
+ [p1] = r0;
+
+ p0.l = _saved_dcplb_fault_addr;
+ p0.h = _saved_dcplb_fault_addr;
+ p1.l = _init_saved_dcplb_fault_addr;
+ p1.h = _init_saved_dcplb_fault_addr;
+ r0 = [p0];
+ [p1] = r0;
+
+ p0.l = _saved_icplb_fault_addr;
+ p0.h = _saved_icplb_fault_addr;
+ p1.l = _init_saved_icplb_fault_addr;
+ p1.h = _init_saved_icplb_fault_addr;
+ r0 = [p0];
+ [p1] = r0;
+
+ p0.l = _saved_seqstat;
+ p0.h = _saved_seqstat;
+ p1.l = _init_saved_seqstat;
+ p1.h = _init_saved_seqstat;
+ r0 = [p0];
+ [p1] = r0;
+#endif
+
/* Initialize stack pointer */
sp.l = lo(INITIAL_STACK);
sp.h = hi(INITIAL_STACK);
