Commit-ID: 6916ce3ffff80f0102d39922ddb3b8c4540f2ea2
Gitweb: http://git.kernel.org/tip/6916ce3ffff80f0102d39922ddb3b8c4540f2ea2
Author: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
AuthorDate: Wed, 29 Jul 2015 12:14:42 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 4 Aug 2015 09:38:00 +0200
sched, MIPS: Get rid of finish_arch_switch()
MIPS was using finish_arch_switch() as a hook to restore and initialize
CPU context for all threads, even newly created kernel and user threads.
This is however entirely solvable within switch_to() so get rid of
finish_arch_switch() which is in the way of scheduler cleanups.
Signed-off-by: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
arch/mips/include/asm/switch_to.h | 48 +++++++++++++++++++--------------------
1 file changed, 23 insertions(+), 25 deletions(-)
diff --git a/arch/mips/include/asm/switch_to.h b/arch/mips/include/asm/switch_to.h
index 7163cd7..9733cd0 100644
--- a/arch/mips/include/asm/switch_to.h
+++ b/arch/mips/include/asm/switch_to.h
@@ -83,45 +83,43 @@ do { if (cpu_has_rw_llb) { \
} \
} while (0)
+/*
+ * For newly created kernel threads switch_to() will return to
+ * ret_from_kernel_thread, newly created user threads to ret_from_fork.
+ * That is, everything following resume() will be skipped for new threads.
+ * So everything that matters to new threads should be placed before resume().
+ */
#define switch_to(prev, next, last) \
do { \
- u32 __c0_stat; \
s32 __fpsave = FP_SAVE_NONE; \
__mips_mt_fpaff_switch_to(prev); \
- if (cpu_has_dsp) \
+ if (cpu_has_dsp) { \
__save_dsp(prev); \
- if (cop2_present && (KSTK_STATUS(prev) & ST0_CU2)) { \
- if (cop2_lazy_restore) \
- KSTK_STATUS(prev) &= ~ST0_CU2; \
- __c0_stat = read_c0_status(); \
- write_c0_status(__c0_stat | ST0_CU2); \
- cop2_save(prev); \
- write_c0_status(__c0_stat & ~ST0_CU2); \
+ __restore_dsp(next); \
+ } \
+ if (cop2_present) { \
+ set_c0_status(ST0_CU2); \
+ if ((KSTK_STATUS(prev) & ST0_CU2)) { \
+ if (cop2_lazy_restore) \
+ KSTK_STATUS(prev) &= ~ST0_CU2; \
+ cop2_save(prev); \
+ } \
+ if (KSTK_STATUS(next) & ST0_CU2 && \
+ !cop2_lazy_restore) { \
+ cop2_restore(next); \
+ } \
+ clear_c0_status(ST0_CU2); \
} \
__clear_software_ll_bit(); \
if (test_and_clear_tsk_thread_flag(prev, TIF_USEDFPU)) \
__fpsave = FP_SAVE_SCALAR; \
if (test_and_clear_tsk_thread_flag(prev, TIF_USEDMSA)) \
__fpsave = FP_SAVE_VECTOR; \
- (last) = resume(prev, next, task_thread_info(next), __fpsave); \
-} while (0)
-
-#define finish_arch_switch(prev) \
-do { \
- u32 __c0_stat; \
- if (cop2_present && !cop2_lazy_restore && \
- (KSTK_STATUS(current) & ST0_CU2)) { \
- __c0_stat = read_c0_status(); \
- write_c0_status(__c0_stat | ST0_CU2); \
- cop2_restore(current); \
- write_c0_status(__c0_stat & ~ST0_CU2); \
- } \
- if (cpu_has_dsp) \
- __restore_dsp(current); \
if (cpu_has_userlocal) \
- write_c0_userlocal(current_thread_info()->tp_value); \
+ write_c0_userlocal(task_thread_info(next)->tp_value); \
__restore_watch(); \
disable_msa(); \
+ (last) = resume(prev, next, task_thread_info(next), __fpsave); \
} while (0)
#endif /* _ASM_SWITCH_TO_H */
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