diff options
| author |   Anton Blanchard <anton@samba.org> | 2015-10-29 11:43:57 +1100 |
|---|---|---|
| committer |   Michael Ellerman <mpe@ellerman.id.au> | 2015-12-01 13:52:24 +1100 |
| commit | af1bbc3dd3d501d27da72e1764afe5f5b0d3882d (patch) | |
| tree | 99e12a987162dce90c51b7f7ccb2b3e23b154c4b /arch/powerpc/kernel/fpu.S | |
| parent | powerpc: Remove redundant mflr in _switch (diff) | |
| download | linux-dev-af1bbc3dd3d501d27da72e1764afe5f5b0d3882d.tar.xz linux-dev-af1bbc3dd3d501d27da72e1764afe5f5b0d3882d.zip | |
powerpc: Remove UP only lazy floating point and vector optimisations
The UP only lazy floating point and vector optimisations were written
back when SMP was not common, and neither glibc nor gcc used vector
instructions. Now SMP is very common, glibc aggressively uses vector
instructions and gcc autovectorises.
We want to add new optimisations that apply to both UP and SMP, but
in preparation for that remove these UP only optimisations.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/kernel/fpu.S')
| -rw-r--r-- | arch/powerpc/kernel/fpu.S | 35 |
1 files changed, 0 insertions, 35 deletions
diff --git a/arch/powerpc/kernel/fpu.S b/arch/powerpc/kernel/fpu.S index 38eb79b8a034..50d2352f2cf4 100644 --- a/arch/powerpc/kernel/fpu.S +++ b/arch/powerpc/kernel/fpu.S @@ -132,31 +132,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_VSX) SYNC MTMSRD(r5) /* enable use of fpu now */ isync -/* - * For SMP, we don't do lazy FPU switching because it just gets too - * horrendously complex, especially when a task switches from one CPU - * to another. Instead we call giveup_fpu in switch_to. - */ -#ifndef CONFIG_SMP - LOAD_REG_ADDRBASE(r3, last_task_used_math) - toreal(r3) - PPC_LL r4,ADDROFF(last_task_used_math)(r3) - PPC_LCMPI 0,r4,0 - beq 1f - toreal(r4) - addi r4,r4,THREAD /* want last_task_used_math->thread */ - addi r10,r4,THREAD_FPSTATE - SAVE_32FPVSRS(0, R5, R10) - mffs fr0 - stfd fr0,FPSTATE_FPSCR(r10) - PPC_LL r5,PT_REGS(r4) - toreal(r5) - PPC_LL r4,_MSR-STACK_FRAME_OVERHEAD(r5) - li r10,MSR_FP|MSR_FE0|MSR_FE1 - andc r4,r4,r10 /* disable FP for previous task */ - PPC_STL r4,_MSR-STACK_FRAME_OVERHEAD(r5) -1: -#endif /* CONFIG_SMP */ /* enable use of FP after return */ #ifdef CONFIG_PPC32 mfspr r5,SPRN_SPRG_THREAD /* current task's THREAD (phys) */ @@ -175,11 +150,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_VSX) lfd fr0,FPSTATE_FPSCR(r10) MTFSF_L(fr0) REST_32FPVSRS(0, R4, R10) -#ifndef CONFIG_SMP - subi r4,r5,THREAD - fromreal(r4) - PPC_STL r4,ADDROFF(last_task_used_math)(r3) -#endif /* CONFIG_SMP */ /* restore registers and return */ /* we haven't used ctr or xer or lr */ blr @@ -226,11 +196,6 @@ END_FTR_SECTION_IFSET(CPU_FTR_VSX) andc r4,r4,r3 /* disable FP for previous task */ PPC_STL r4,_MSR-STACK_FRAME_OVERHEAD(r5) 1: -#ifndef CONFIG_SMP - li r5,0 - LOAD_REG_ADDRBASE(r4,last_task_used_math) - PPC_STL r5,ADDROFF(last_task_used_math)(r4) -#endif /* CONFIG_SMP */ blr /* |