[MIPS] MT: Improved multithreading support.
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/kernel/genex.S b/arch/mips/kernel/genex.S
index 04418b6..ff7af36 100644
--- a/arch/mips/kernel/genex.S
+++ b/arch/mips/kernel/genex.S
@@ -12,6 +12,7 @@
#include <linux/init.h>
#include <asm/asm.h>
+#include <asm/asmmacro.h>
#include <asm/cacheops.h>
#include <asm/regdef.h>
#include <asm/fpregdef.h>
@@ -171,6 +172,15 @@
SAVE_AT
.set push
.set noreorder
+#ifdef CONFIG_MIPS_MT_SMTC
+ /*
+ * To keep from blindly blocking *all* interrupts
+ * during service by SMTC kernel, we also want to
+ * pass the IM value to be cleared.
+ */
+EXPORT(except_vec_vi_mori)
+ ori a0, $0, 0
+#endif /* CONFIG_MIPS_MT_SMTC */
EXPORT(except_vec_vi_lui)
lui v0, 0 /* Patched */
j except_vec_vi_handler
@@ -187,6 +197,25 @@
NESTED(except_vec_vi_handler, 0, sp)
SAVE_TEMP
SAVE_STATIC
+#ifdef CONFIG_MIPS_MT_SMTC
+ /*
+ * SMTC has an interesting problem that interrupts are level-triggered,
+ * and the CLI macro will clear EXL, potentially causing a duplicate
+ * interrupt service invocation. So we need to clear the associated
+ * IM bit of Status prior to doing CLI, and restore it after the
+ * service routine has been invoked - we must assume that the
+ * service routine will have cleared the state, and any active
+ * level represents a new or otherwised unserviced event...
+ */
+ mfc0 t1, CP0_STATUS
+ and t0, a0, t1
+ mfc0 t2, CP0_TCCONTEXT
+ or t0, t0, t2
+ mtc0 t0, CP0_TCCONTEXT
+ xor t1, t1, t0
+ mtc0 t1, CP0_STATUS
+ ehb
+#endif /* CONFIG_MIPS_MT_SMTC */
CLI
move a0, sp
jalr v0