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[PATCH v3] MIPS: micromips: Fix improper definition of ISA exception bit

To: linux-mips@linux-mips.org
Subject: [PATCH v3] MIPS: micromips: Fix improper definition of ISA exception bit.
From: "Steven J. Hill" <Steven.Hill@imgtec.com>
Date: Tue, 4 Jun 2013 14:09:39 -0500
Cc: "Steven J. Hill" <Steven.Hill@imgtec.com>, ralf@linux-mips.org, ddaney.cavm@gmail.com
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The ISA exception bit selects whether exceptions are taken in classic
MIPS or microMIPS mode. This bit is Config3.ISAOnExc and is bit 16. It
It was improperly defined as bits 16 and 17. Fortunately, bit 17 is
read-only and did not effect microMIPS operation. However, detecting
a classic or microMIPS kernel when examining the /proc/cpuinfo file,
the result always showed a microMIPS kernel.

Signed-off-by: Steven J. Hill <Steven.Hill@imgtec.com>
---
 arch/mips/include/asm/mipsregs.h |    2 +-
 arch/mips/kernel/cpu-probe.c     |    7 ++-----
 arch/mips/mti-malta/malta-init.c |    7 +++++++
 arch/mips/mti-sead3/sead3-init.c |    7 +++++++
 4 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/arch/mips/include/asm/mipsregs.h b/arch/mips/include/asm/mipsregs.h
index 87e6207..fed1c3e 100644
--- a/arch/mips/include/asm/mipsregs.h
+++ b/arch/mips/include/asm/mipsregs.h
@@ -596,7 +596,7 @@
 #define MIPS_CONF3_RXI         (_ULCAST_(1) << 12)
 #define MIPS_CONF3_ULRI                (_ULCAST_(1) << 13)
 #define MIPS_CONF3_ISA         (_ULCAST_(3) << 14)
-#define MIPS_CONF3_ISA_OE      (_ULCAST_(3) << 16)
+#define MIPS_CONF3_ISA_OE      (_ULCAST_(1) << 16)
 #define MIPS_CONF3_VZ          (_ULCAST_(1) << 23)
 
 #define MIPS_CONF4_MMUSIZEEXT  (_ULCAST_(255) << 0)
diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
index c6568bf..d6c5230 100644
--- a/arch/mips/kernel/cpu-probe.c
+++ b/arch/mips/kernel/cpu-probe.c
@@ -256,6 +256,8 @@ static inline unsigned int decode_config3(struct 
cpuinfo_mips *c)
                c->ases |= MIPS_ASE_SMARTMIPS;
                c->options |= MIPS_CPU_RIXI;
        }
+       if (config3 & MIPS_CONF3_ISA)
+               c->options |= MIPS_CPU_MICROMIPS;
        if (config3 & MIPS_CONF3_RXI)
                c->options |= MIPS_CPU_RIXI;
        if (config3 & MIPS_CONF3_DSP)
@@ -270,11 +272,6 @@ static inline unsigned int decode_config3(struct 
cpuinfo_mips *c)
                c->ases |= MIPS_ASE_MIPSMT;
        if (config3 & MIPS_CONF3_ULRI)
                c->options |= MIPS_CPU_ULRI;
-       if (config3 & MIPS_CONF3_ISA)
-               c->options |= MIPS_CPU_MICROMIPS;
-#ifdef CONFIG_CPU_MICROMIPS
-       write_c0_config3(read_c0_config3() | MIPS_CONF3_ISA_OE);
-#endif
        if (config3 & MIPS_CONF3_VZ)
                c->ases |= MIPS_ASE_VZ;
 
diff --git a/arch/mips/mti-malta/malta-init.c b/arch/mips/mti-malta/malta-init.c
index ff8caff..3598f1d 100644
--- a/arch/mips/mti-malta/malta-init.c
+++ b/arch/mips/mti-malta/malta-init.c
@@ -106,6 +106,13 @@ extern struct plat_smp_ops msmtc_smp_ops;
 
 void __init prom_init(void)
 {
+#ifdef CONFIG_CPU_MICROMIPS
+       unsigned int config3 = read_c0_config3();
+
+       if (config3 & MIPS_CONF3_ISA)
+               write_c0_config3(config3 | MIPS_CONF3_ISA_OE);
+#endif
+
        mips_display_message("LINUX");
 
        /*
diff --git a/arch/mips/mti-sead3/sead3-init.c b/arch/mips/mti-sead3/sead3-init.c
index bfbd17b..e68bfd3 100644
--- a/arch/mips/mti-sead3/sead3-init.c
+++ b/arch/mips/mti-sead3/sead3-init.c
@@ -130,6 +130,13 @@ static void __init mips_ejtag_setup(void)
 
 void __init prom_init(void)
 {
+#ifdef CONFIG_CPU_MICROMIPS
+       unsigned int config3 = read_c0_config3();
+
+       if (config3 & MIPS_CONF3_ISA)
+               write_c0_config3(config3 | MIPS_CONF3_ISA_OE);
+#endif
+
        board_nmi_handler_setup = mips_nmi_setup;
        board_ejtag_handler_setup = mips_ejtag_setup;
 
-- 
1.7.2.5


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