MIPS: microMIPS: Add support for exception handling.
All exceptions must be taken in microMIPS mode, never in classic
MIPS mode or the kernel falls apart. A few NOP instructions are
used to maintain the correct alignment of microMIPS versions of
the exception vectors.
Signed-off-by: Steven J. Hill <Steven.Hill@imgtec.com>
diff --git a/arch/mips/kernel/genex.S b/arch/mips/kernel/genex.S
index 5360b1d..5c2ba9f 100644
--- a/arch/mips/kernel/genex.S
+++ b/arch/mips/kernel/genex.S
@@ -5,8 +5,8 @@
*
* Copyright (C) 1994 - 2000, 2001, 2003 Ralf Baechle
* Copyright (C) 1999, 2000 Silicon Graphics, Inc.
- * Copyright (C) 2001 MIPS Technologies, Inc.
* Copyright (C) 2002, 2007 Maciej W. Rozycki
+ * Copyright (C) 2001, 2012 MIPS Technologies, Inc. All rights reserved.
*/
#include <linux/init.h>
@@ -21,8 +21,10 @@
#include <asm/war.h>
#include <asm/thread_info.h>
+#ifdef CONFIG_MIPS_MT_SMTC
#define PANIC_PIC(msg) \
- .set push; \
+ .set push; \
+ .set nomicromips; \
.set reorder; \
PTR_LA a0,8f; \
.set noat; \
@@ -31,17 +33,10 @@
9: b 9b; \
.set pop; \
TEXT(msg)
+#endif
__INIT
-NESTED(except_vec0_generic, 0, sp)
- PANIC_PIC("Exception vector 0 called")
- END(except_vec0_generic)
-
-NESTED(except_vec1_generic, 0, sp)
- PANIC_PIC("Exception vector 1 called")
- END(except_vec1_generic)
-
/*
* General exception vector for all other CPUs.
*
@@ -138,12 +133,19 @@
nop
nop
nop
+#ifdef CONFIG_CPU_MICROMIPS
+ nop
+ nop
+ nop
+ nop
+#endif
.set mips3
wait
/* end of rollback region (the region size must be power of two) */
- .set pop
1:
jr ra
+ nop
+ .set pop
END(r4k_wait)
.macro BUILD_ROLLBACK_PROLOGUE handler
@@ -201,7 +203,11 @@
LONG_L s0, TI_REGS($28)
LONG_S sp, TI_REGS($28)
PTR_LA ra, ret_from_irq
- j plat_irq_dispatch
+ PTR_LA v0, plat_irq_dispatch
+ jr v0
+#ifdef CONFIG_CPU_MICROMIPS
+ nop
+#endif
END(handle_int)
__INIT
@@ -222,11 +228,14 @@
/*
* EJTAG debug exception handler.
* The EJTAG debug exception entry point is 0xbfc00480, which
- * normally is in the boot PROM, so the boot PROM must do a
+ * normally is in the boot PROM, so the boot PROM must do an
* unconditional jump to this vector.
*/
NESTED(except_vec_ejtag_debug, 0, sp)
j ejtag_debug_handler
+#ifdef CONFIG_CPU_MICROMIPS
+ nop
+#endif
END(except_vec_ejtag_debug)
__FINIT
@@ -251,9 +260,10 @@
FEXPORT(except_vec_vi_mori)
ori a0, $0, 0
#endif /* CONFIG_MIPS_MT_SMTC */
+ PTR_LA v1, except_vec_vi_handler
FEXPORT(except_vec_vi_lui)
lui v0, 0 /* Patched */
- j except_vec_vi_handler
+ jr v1
FEXPORT(except_vec_vi_ori)
ori v0, 0 /* Patched */
.set pop
@@ -354,6 +364,9 @@
*/
NESTED(except_vec_nmi, 0, sp)
j nmi_handler
+#ifdef CONFIG_CPU_MICROMIPS
+ nop
+#endif
END(except_vec_nmi)
__FINIT
@@ -500,13 +513,35 @@
.set push
.set noat
.set noreorder
- /* 0x7c03e83b: rdhwr v1,$29 */
+ /* MIPS32: 0x7c03e83b: rdhwr v1,$29 */
+ /* microMIPS: 0x007d6b3c: rdhwr v1,$29 */
MFC0 k1, CP0_EPC
- lui k0, 0x7c03
- lw k1, (k1)
- ori k0, 0xe83b
- .set reorder
+#if defined(CONFIG_CPU_MICROMIPS) || defined(CONFIG_CPU_MIPS32_R2) || defined(CONFIG_CPU_MIPS64_R2)
+ and k0, k1, 1
+ beqz k0, 1f
+ xor k1, k0
+ lhu k0, (k1)
+ lhu k1, 2(k1)
+ ins k1, k0, 16, 16
+ lui k0, 0x007d
+ b docheck
+ ori k0, 0x6b3c
+1:
+ lui k0, 0x7c03
+ lw k1, (k1)
+ ori k0, 0xe83b
+#else
+ andi k0, k1, 1
+ bnez k0, handle_ri
+ lui k0, 0x7c03
+ lw k1, (k1)
+ ori k0, 0xe83b
+#endif
+ .set reorder
+docheck:
bne k0, k1, handle_ri /* if not ours */
+
+isrdhwr:
/* The insn is rdhwr. No need to check CAUSE.BD here. */
get_saved_sp /* k1 := current_thread_info */
.set noreorder