diff options
| author | Paul Burton <paul.burton@imgtec.com> | 2015-08-03 08:49:30 -0700 |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2015-09-03 12:08:05 +0200 |
| commit | 1a3d59579b9f436da038f377309cf2270c76318e (patch) | |
| tree | 3a7c9ca24e6826642d414bfd6750d94c4eefacb6 /arch/mips/kernel | |
| parent | 23eb6f4016758b756b54704b359e3c51d425d6ab (diff) | |
| download | linux-1a3d59579b9f436da038f377309cf2270c76318e.tar.bz2 | |
MIPS: Tidy up FPU context switching
Rather than saving the scalar FP or vector context in the assembly
resume function, reuse the existing C code we have in fpu.h to do
exactly that. This reduces duplication, results in a much easier to read
resume function & should allow the compiler to optimise out more MSA
code due to is_msa_enabled()/cpu_has_msa being known-zero at compile
time for kernels without MSA support.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com>
Cc: Maciej W. Rozycki <macro@linux-mips.org>
Cc: linux-kernel@vger.kernel.org
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Markos Chandras <markos.chandras@imgtec.com>
Cc: Manuel Lauss <manuel.lauss@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/10830/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/kernel')
| -rw-r--r-- | arch/mips/kernel/r4k_switch.S | 41 |
1 files changed, 1 insertions, 40 deletions
diff --git a/arch/mips/kernel/r4k_switch.S b/arch/mips/kernel/r4k_switch.S index 04cbbde3521b..92cd0516ecf5 100644 --- a/arch/mips/kernel/r4k_switch.S +++ b/arch/mips/kernel/r4k_switch.S @@ -34,7 +34,7 @@ #ifndef USE_ALTERNATE_RESUME_IMPL /* * task_struct *resume(task_struct *prev, task_struct *next, - * struct thread_info *next_ti, s32 fp_save) + * struct thread_info *next_ti) */ .align 5 LEAF(resume) @@ -43,45 +43,6 @@ cpu_save_nonscratch a0 LONG_S ra, THREAD_REG31(a0) - /* - * Check whether we need to save any FP context. FP context is saved - * iff the process has used the context with the scalar FPU or the MSA - * ASE in the current time slice, as indicated by _TIF_USEDFPU and - * _TIF_USEDMSA respectively. switch_to will have set fp_save - * accordingly to an FP_SAVE_ enum value. - */ - beqz a3, 2f - - /* - * We do. Clear the saved CU1 bit for prev, such that next time it is - * scheduled it will start in userland with the FPU disabled. If the - * task uses the FPU then it will be enabled again via the do_cpu trap. - * This allows us to lazily restore the FP context. - */ - PTR_L t3, TASK_THREAD_INFO(a0) - LONG_L t0, ST_OFF(t3) - li t1, ~ST0_CU1 - and t0, t0, t1 - LONG_S t0, ST_OFF(t3) - - /* Check whether we're saving scalar or vector context. */ - bgtz a3, 1f - - /* Save 128b MSA vector context + scalar FP control & status. */ - .set push - SET_HARDFLOAT - cfc1 t1, fcr31 - msa_save_all a0 - .set pop /* SET_HARDFLOAT */ - - sw t1, THREAD_FCR31(a0) - b 2f - -1: /* Save 32b/64b scalar FP context. */ - fpu_save_double a0 t0 t1 # c0_status passed in t0 - # clobbers t1 -2: - #if defined(CONFIG_CC_STACKPROTECTOR) && !defined(CONFIG_SMP) PTR_LA t8, __stack_chk_guard LONG_L t9, TASK_STACK_CANARY(a1) |