From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Michael Neuling To: benh@kernel.crashing.org MIME-Version: 1.0 Subject: [PATCH] powerpc: DSCR FSCR cleanup Date: Mon, 26 Aug 2013 13:55:57 +1000 Message-ID: <24883.1377489357@ale.ozlabs.ibm.com> Cc: Linux PPC dev , Paul Mackerras List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 -- arch/powerpc/kernel/entry_64.S | 31 ++++++------------------------- arch/powerpc/kernel/traps.c | 7 ++----- 2 files changed, 8 insertions(+), 30 deletions(-) diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S index 2bd0b88..513dc4d 100644 --- a/arch/powerpc/kernel/entry_64.S +++ b/arch/powerpc/kernel/entry_64.S @@ -575,34 +575,15 @@ 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: diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c index e435bc0..0ba68a2 100644 --- a/arch/powerpc/kernel/traps.c +++ b/arch/powerpc/kernel/traps.c @@ -1322,13 +1322,10 @@ void facility_unavailable_exception(struct pt_regs *regs) if (status == FSCR_DSCR_LG) { /* User is acessing the DSCR. Set the inherit bit and allow * the user to set it directly in future by setting via the - * H/FSCR DSCR bit. + * FSCR DSCR bit. We always leave HFSCR DSCR set. */ current->thread.dscr_inherit = 1; - if (hv) - mtspr(SPRN_HFSCR, value | HFSCR_DSCR); - else - mtspr(SPRN_FSCR, value | FSCR_DSCR); + mtspr(SPRN_FSCR, value | FSCR_DSCR); return; }