[PATCH 3.19 081/175] MIPS: asm: pgtable: Add c0 hazards on HTW start/stop sequences

Greg Kroah-Hartman
2015-03-04T06:51:12Z

From: Markos Chandras <markos.chandras@imgtec.com>

commit 461d1597ffad7a826f8aaa63ab0727c37b632e34 upstream.

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: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9114/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/mips/include/asm/pgtable.h | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)

--- a/arch/mips/include/asm/pgtable.h
+++ b/arch/mips/include/asm/pgtable.h
@@ -99,16 +99,20 @@ extern void paging_init(void);

#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 { \
do { \
if (cpu_has_htw) { \
htw_stop(); \
- back_to_back_c0_hazard(); \
htw_start(); \
- back_to_back_c0_hazard(); \
} \
} while(0)