Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965392AbbDQQdG (ORCPT ); Fri, 17 Apr 2015 12:33:06 -0400 Received: from pegase1.c-s.fr ([93.17.236.30]:45043 "EHLO mailhub1.si.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754446AbbDQQdD (ORCPT ); Fri, 17 Apr 2015 12:33:03 -0400 Message-Id: <04fd0663392681a88fac90c851b0d767484786f5.1429287688.git.christophe.leroy@c-s.fr> In-Reply-To: References: Subject: [PATCH v5 3/5] powerpc/8xx: dont save CR in SCRATCH registers To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , scottwood@freescale.com Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Joakim Tjernlund Date: Fri, 17 Apr 2015 18:32:56 +0200 (CEST) From: christophe.leroy@c-s.fr (root) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3107 Lines: 99 CR only needs to be preserved when checking if we are handling a kernel address. So we can preserve CR in a register: - In ITLBMiss, check is done only when CONFIG_MODULES is defined. Otherwise we don't need to do anything at all with CR. - We use r10, then we reload SRR0/MD_EPN into r10 when CR is restored Signed-off-by: Christophe Leroy --- arch/powerpc/kernel/head_8xx.S | 29 +++++++++++++++-------------- 1 file changed, 15 insertions(+), 14 deletions(-) diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S index 5a69c5e..150d03f 100644 --- a/arch/powerpc/kernel/head_8xx.S +++ b/arch/powerpc/kernel/head_8xx.S @@ -312,10 +312,6 @@ InstructionTLBMiss: mtspr SPRN_DAR, r3 #endif EXCEPTION_PROLOG_0 - mfcr r10 - mtspr SPRN_SPRG_SCRATCH2, r10 - mfspr r10, SPRN_SRR0 /* Get effective address of fault */ - INVALIDATE_ADJACENT_PAGES_CPU15(r11, r10) /* If we are faulting a kernel address, we have to use the * kernel page tables. @@ -323,13 +319,20 @@ InstructionTLBMiss: #ifdef CONFIG_MODULES /* Only modules will cause ITLB Misses as we always * pin the first 8MB of kernel memory */ - andis. r11, r10, 0x8000 /* Address >= 0x80000000 */ -#endif + mfspr r11, SPRN_SRR0 /* Get effective address of fault */ + INVALIDATE_ADJACENT_PAGES_CPU15(r10, r11) + mfcr r10 + andis. r11, r11, 0x8000 /* Address >= 0x80000000 */ mfspr r11, SPRN_M_TW /* Get level 1 table */ -#ifdef CONFIG_MODULES beq 3f lis r11, (swapper_pg_dir-PAGE_OFFSET)@ha 3: + mtcr r10 + mfspr r10, SPRN_SRR0 /* Get effective address of fault */ +#else + mfspr r10, SPRN_SRR0 /* Get effective address of fault */ + INVALIDATE_ADJACENT_PAGES_CPU15(r11, r10) + mfspr r11, SPRN_M_TW /* Get level 1 table base address */ #endif /* Insert level 1 index */ rlwimi r11, r10, 32 - ((PAGE_SHIFT - 2) << 1), (PAGE_SHIFT - 2) << 1, 29 @@ -362,8 +365,6 @@ InstructionTLBMiss: mfspr r3, SPRN_DAR mtspr SPRN_DAR, r11 /* Tag DAR */ #endif - mfspr r10, SPRN_SPRG_SCRATCH2 - mtcr r10 EXCEPTION_EPILOG_0 rfi @@ -374,17 +375,19 @@ DataStoreTLBMiss: #endif EXCEPTION_PROLOG_0 mfcr r10 - mtspr SPRN_SPRG_SCRATCH2, r10 - mfspr r10, SPRN_MD_EPN /* If we are faulting a kernel address, we have to use the * kernel page tables. */ - andis. r11, r10, 0x8000 + mfspr r11, SPRN_MD_EPN + andis. r11, r11, 0x8000 mfspr r11, SPRN_M_TW /* Get level 1 table */ beq 3f lis r11, (swapper_pg_dir-PAGE_OFFSET)@ha 3: + mtcr r10 + mfspr r10, SPRN_MD_EPN + /* Insert level 1 index */ rlwimi r11, r10, 32 - ((PAGE_SHIFT - 2) << 1), (PAGE_SHIFT - 2) << 1, 29 lwz r11, (swapper_pg_dir-PAGE_OFFSET)@l(r11) /* Get the level 1 entry */ @@ -438,8 +441,6 @@ DataStoreTLBMiss: mfspr r3, SPRN_DAR #endif mtspr SPRN_DAR, r11 /* Tag DAR */ - mfspr r10, SPRN_SPRG_SCRATCH2 - mtcr r10 EXCEPTION_EPILOG_0 rfi -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/