MIPS: asm: pgtable: Add c0 hazards on HTW start/stop sequences
When we use htw_{start,stop}() outside of htw_reset(), we need
to ensure that c0 changes have been propagated properly before
we attempt to continue with subsequence memory operations.
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: <stable@vger.kernel.org> # 3.17+
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9114/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
index 62a6ba3..45d7fd5 100644
--- a/arch/mips/include/asm/pgtable.h
+++ b/arch/mips/include/asm/pgtable.h
@@ -99,16 +99,20 @@
#define htw_stop() \
do { \
- if (cpu_has_htw) \
+ if (cpu_has_htw) { \
write_c0_pwctl(read_c0_pwctl() & \
~(1 << MIPS_PWCTL_PWEN_SHIFT)); \
+ back_to_back_c0_hazard(); \
+ } \
} while(0)
#define htw_start() \
do { \
- if (cpu_has_htw) \
+ if (cpu_has_htw) { \
write_c0_pwctl(read_c0_pwctl() | \
(1 << MIPS_PWCTL_PWEN_SHIFT)); \
+ back_to_back_c0_hazard(); \
+ } \
} while(0)
@@ -116,9 +120,7 @@
do { \
if (cpu_has_htw) { \
htw_stop(); \
- back_to_back_c0_hazard(); \
htw_start(); \
- back_to_back_c0_hazard(); \
} \
} while(0)