diff options
| author | Michael Neuling <mikey@neuling.org> | 2013-08-26 13:55:57 +1000 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2013-08-27 15:05:22 +1000 |
| commit | bc683a7e51c5c838bc74316125bebec92af74f12 (patch) | |
| tree | 5e747e76bff1b853ec1a97dbb2fdb37f89d76460 /arch/powerpc/kernel/entry_64.S | |
| parent | 3f1f4311881b330a7b5429dd101e676df191b159 (diff) | |
powerpc: Cleanup handling of the DSCR bit in the FSCR register
As suggested by paulus we can simplify the Data Stream Control Register
(DSCR) Facility Status and Control Register (FSCR) handling.
Firstly, we simplify the asm by using a rldimi.
Secondly, we now use the FSCR only to control the DSCR facility, rather
than both the FSCR and HFSCR. Users will see no functional change from
this but will get a minor speedup as they will trap into the kernel only
once (rather than twice) when they first touch the DSCR. Also, this
changes removes a bunch of ugly FTR_SECTION code.
Signed-off-by: Michael Neuling <mikey@neuling.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/kernel/entry_64.S')
| -rw-r--r-- | arch/powerpc/kernel/entry_64.S | 31 |
1 files changed, 6 insertions, 25 deletions
diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S index 4524500f30d6..c04cdf70d487 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -578,34 +578,15 @@ BEGIN_FTR_SECTION ld r7,DSCR_DEFAULT@toc(2) ld r0,THREAD_DSCR(r4) cmpwi r6,0 - li r8, FSCR_DSCR bne 1f ld r0,0(r7) - b 3f 1: - BEGIN_FTR_SECTION_NESTED(70) - mfspr r6, SPRN_FSCR - or r6, r6, r8 - mtspr SPRN_FSCR, r6 - BEGIN_FTR_SECTION_NESTED(69) - mfspr r6, SPRN_HFSCR - or r6, r6, r8 - mtspr SPRN_HFSCR, r6 - END_FTR_SECTION_NESTED(CPU_FTR_HVMODE, CPU_FTR_HVMODE, 69) - b 4f - END_FTR_SECTION_NESTED(CPU_FTR_ARCH_207S, CPU_FTR_ARCH_207S, 70) -3: - BEGIN_FTR_SECTION_NESTED(70) - mfspr r6, SPRN_FSCR - andc r6, r6, r8 - mtspr SPRN_FSCR, r6 - BEGIN_FTR_SECTION_NESTED(69) - mfspr r6, SPRN_HFSCR - andc r6, r6, r8 - mtspr SPRN_HFSCR, r6 - END_FTR_SECTION_NESTED(CPU_FTR_HVMODE, CPU_FTR_HVMODE, 69) - END_FTR_SECTION_NESTED(CPU_FTR_ARCH_207S, CPU_FTR_ARCH_207S, 70) -4: cmpd r0,r25 +BEGIN_FTR_SECTION_NESTED(70) + mfspr r8, SPRN_FSCR + rldimi r8, r6, FSCR_DSCR_LG, (63 - FSCR_DSCR_LG) + mtspr SPRN_FSCR, r8 +END_FTR_SECTION_NESTED(CPU_FTR_ARCH_207S, CPU_FTR_ARCH_207S, 70) + cmpd r0,r25 beq 2f mtspr SPRN_DSCR,r0 2: |