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-rw-r--r--arch/blackfin/kernel/traps.c8
-rw-r--r--arch/blackfin/mach-common/entry.S69
2 files changed, 62 insertions, 15 deletions
diff --git a/arch/blackfin/kernel/traps.c b/arch/blackfin/kernel/traps.c
index 1a8a5f171bc..ba68eb2ec92 100644
--- a/arch/blackfin/kernel/traps.c
+++ b/arch/blackfin/kernel/traps.c
@@ -132,6 +132,14 @@ static int printk_address(unsigned long address)
}
#endif
+asmlinkage void double_fault_c(struct pt_regs *fp)
+{
+ printk(KERN_EMERG "\n" KERN_EMERG "Double Fault\n");
+ dump_bfin_regs(fp, (void *)fp->retx);
+ panic("Double Fault - unrecoverable event\n");
+
+}
+
asmlinkage void trap_c(struct pt_regs *fp)
{
#ifdef CONFIG_DEBUG_BFIN_HWTRACE_ON
diff --git a/arch/blackfin/mach-common/entry.S b/arch/blackfin/mach-common/entry.S
index 3feca05694f..e2239361cac 100644
--- a/arch/blackfin/mach-common/entry.S
+++ b/arch/blackfin/mach-common/entry.S
@@ -29,21 +29,7 @@
* 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
-/*
- * 25-Dec-2004 - LG Soft India
- * 1. Fix in return_from_int, to make sure any pending
- * system call in ILAT for this process to get
- * executed, otherwise in case context switch happens,
- * system call of first process (i.e in ILAT) will be
- * carried forward to the switched process.
- * 2. Removed Constant references for the following
- * a. IPEND
- * b. EXCAUSE mask
- * c. PAGE Mask
- */
-
-/*
- * NOTE: This code handles signal-recognition, which happens every time
+/* NOTE: This code handles signal-recognition, which happens every time
* after a timer-interrupt and after each system call.
*/
@@ -175,6 +161,13 @@ ENTRY(_ex_replaceable)
nop;
ENTRY(_ex_trap_c)
+ /* Make sure we are not in a double fault */
+ p4.l = lo(IPEND);
+ p4.h = hi(IPEND);
+ r7 = [p4];
+ CC = BITTST (r7, 5);
+ if CC jump _double_fault;
+
/* Call C code (trap_c) to handle the exception, which most
* likely involves sending a signal to the current process.
* To avoid double faults, lower our priority to IRQ5 first.
@@ -220,6 +213,52 @@ ENTRY(_ex_trap_c)
rtx;
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
+ */
+
+ 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;
+
+ 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;
+
+ /* We should be out of the exception stack, and back down into
+ * kernel or user space stack
+ */
+ SAVE_ALL_SYS
+
+ 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
+
+ENDPROC(_double_fault)
+
ENTRY(_exception_to_level5)
SAVE_ALL_SYS