From nobody Fri Dec 19 17:39:42 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E75AECD4853 for ; Mon, 25 Sep 2023 18:34:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233109AbjIYSey (ORCPT ); Mon, 25 Sep 2023 14:34:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40224 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233465AbjIYSeT (ORCPT ); Mon, 25 Sep 2023 14:34:19 -0400 Received: from pegase1.c-s.fr (pegase1.c-s.fr [93.17.236.30]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E64F7E54 for ; Mon, 25 Sep 2023 11:34:03 -0700 (PDT) Received: from localhost (mailhub3.si.c-s.fr [192.168.12.233]) by localhost (Postfix) with ESMTP id 4RvWgb0f4tz9vB5; Mon, 25 Sep 2023 20:32:11 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Z8pshZZK-3LD; Mon, 25 Sep 2023 20:32:11 +0200 (CEST) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 4RvWg549JMz9vCC; Mon, 25 Sep 2023 20:31:45 +0200 (CEST) Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 8AF808B78D; Mon, 25 Sep 2023 20:31:45 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id si3sGEFU4G8j; Mon, 25 Sep 2023 20:31:45 +0200 (CEST) Received: from PO20335.IDSI0.si.c-s.fr (unknown [192.168.232.137]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 53FA98B796; Mon, 25 Sep 2023 20:31:44 +0200 (CEST) Received: from PO20335.IDSI0.si.c-s.fr (localhost [127.0.0.1]) by PO20335.IDSI0.si.c-s.fr (8.17.1/8.16.1) with ESMTPS id 38PIVa901499256 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Mon, 25 Sep 2023 20:31:37 +0200 Received: (from chleroy@localhost) by PO20335.IDSI0.si.c-s.fr (8.17.1/8.17.1/Submit) id 38PIVaYq1499255; Mon, 25 Sep 2023 20:31:36 +0200 X-Authentication-Warning: PO20335.IDSI0.si.c-s.fr: chleroy set sender to christophe.leroy@csgroup.eu using -f From: Christophe Leroy To: Michael Ellerman , Nicholas Piggin Cc: Christophe Leroy , linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: [PATCH v2 31/37] powerpc/44x: Introduce _PAGE_READ and remove _PAGE_USER Date: Mon, 25 Sep 2023 20:31:45 +0200 Message-ID: <043e17987b260b99b45094138c6cb2e89e63d499.1695659959.git.christophe.leroy@csgroup.eu> X-Mailer: git-send-email 2.41.0 In-Reply-To: References: MIME-Version: 1.0 X-Developer-Signature: v=1; a=ed25519-sha256; t=1695666676; l=6805; i=christophe.leroy@csgroup.eu; s=20211009; h=from:subject:message-id; bh=s3BNmCTyHq/3Leje/kEdJnaf/h+UARDFS74k4QUIx6k=; b=F+70dNnr2iuxXun14KGvdnmBBX+kp76oU3lq+4q45o0E9OteEMoCbM10qMvLVAjlk/ITXDd5R W8cZ3IhMwOkAp+0w490vk+UDZb05r7Awd0Uj0ysxtG4A1YUdZ3QzuW6 X-Developer-Key: i=christophe.leroy@csgroup.eu; a=ed25519; pk=HIzTzUj91asvincQGOFx6+ZF5AoUuP9GdOtQChs7Mm0= Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" 44x MMU has 6 page protection bits: - R, W, X for supervisor - R, W, X for user It means that it can support X without R. To do that, _PAGE_READ flag is needed but there is no bit available for it in PTE. On the other hand the only real use of _PAGE_USER is to implement PAGE_NONE by clearing _PAGE_USER. As _PAGE_NONE can also be implemented by clearing _PAGE_READ, remove _PAGE_USER and add _PAGE_READ. In order to insert bits in one go during TLB miss, move _PAGE_ACCESSED and put _PAGE_READ just after _PAGE_DIRTY so that _PAGE_DIRTY is copied into SW and _PAGE_READ into SR at once. With that change, 44x now also honors execute-only protection. Signed-off-by: Christophe Leroy --- arch/powerpc/include/asm/nohash/32/pte-44x.h | 22 +++--------- arch/powerpc/kernel/head_44x.S | 36 ++++++++++---------- 2 files changed, 22 insertions(+), 36 deletions(-) diff --git a/arch/powerpc/include/asm/nohash/32/pte-44x.h b/arch/powerpc/in= clude/asm/nohash/32/pte-44x.h index fc0c075006ea..851813725237 100644 --- a/arch/powerpc/include/asm/nohash/32/pte-44x.h +++ b/arch/powerpc/include/asm/nohash/32/pte-44x.h @@ -63,28 +63,21 @@ */ =20 #define _PAGE_PRESENT 0x00000001 /* S: PTE valid */ -#define _PAGE_RW 0x00000002 /* S: Write permission */ +#define _PAGE_WRITE 0x00000002 /* S: Write permission */ #define _PAGE_EXEC 0x00000004 /* H: Execute permission */ -#define _PAGE_ACCESSED 0x00000008 /* S: Page referenced */ +#define _PAGE_READ 0x00000008 /* S: Read permission */ #define _PAGE_DIRTY 0x00000010 /* S: Page dirty */ #define _PAGE_SPECIAL 0x00000020 /* S: Special page */ -#define _PAGE_USER 0x00000040 /* S: User page */ +#define _PAGE_ACCESSED 0x00000040 /* S: Page referenced */ #define _PAGE_ENDIAN 0x00000080 /* H: E bit */ #define _PAGE_GUARDED 0x00000100 /* H: G bit */ #define _PAGE_COHERENT 0x00000200 /* H: M bit */ #define _PAGE_NO_CACHE 0x00000400 /* H: I bit */ #define _PAGE_WRITETHRU 0x00000800 /* H: W bit */ =20 -#define _PAGE_WRITE _PAGE_RW - /* No page size encoding in the linux PTE */ #define _PAGE_PSIZE 0 =20 -#define _PAGE_KERNEL_RO 0 -#define _PAGE_KERNEL_ROX _PAGE_EXEC -#define _PAGE_KERNEL_RW (_PAGE_DIRTY | _PAGE_RW) -#define _PAGE_KERNEL_RWX (_PAGE_DIRTY | _PAGE_RW | _PAGE_EXEC) - /* TODO: Add large page lowmem mapping support */ #define _PMD_PRESENT 0 #define _PMD_PRESENT_MASK (PAGE_MASK) @@ -107,14 +100,7 @@ #define _PAGE_BASE (_PAGE_BASE_NC) #endif =20 -/* Permission masks used to generate the __P and __S table */ -#define PAGE_NONE __pgprot(_PAGE_BASE) -#define PAGE_SHARED __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW) -#define PAGE_SHARED_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_RW | _PAGE_= EXEC) -#define PAGE_COPY __pgprot(_PAGE_BASE | _PAGE_USER) -#define PAGE_COPY_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC) -#define PAGE_READONLY __pgprot(_PAGE_BASE | _PAGE_USER) -#define PAGE_READONLY_X __pgprot(_PAGE_BASE | _PAGE_USER | _PAGE_EXEC) +#include =20 #endif /* __KERNEL__ */ #endif /* _ASM_POWERPC_NOHASH_32_PTE_44x_H */ diff --git a/arch/powerpc/kernel/head_44x.S b/arch/powerpc/kernel/head_44x.S index 858dabf84432..25642e802ed3 100644 --- a/arch/powerpc/kernel/head_44x.S +++ b/arch/powerpc/kernel/head_44x.S @@ -314,8 +314,8 @@ interrupt_base: * kernel page tables. */ lis r11, PAGE_OFFSET@h - cmplw r10, r11 - blt+ 3f + cmplw cr7, r10, r11 + blt+ cr7, 3f lis r11, swapper_pg_dir@h ori r11, r11, swapper_pg_dir@l =20 @@ -355,7 +355,7 @@ interrupt_base: * place or can we save a couple of instructions here ? */ mfspr r12,SPRN_ESR - li r13,_PAGE_PRESENT|_PAGE_ACCESSED + li r13,_PAGE_PRESENT|_PAGE_ACCESSED|_PAGE_READ rlwimi r13,r12,10,30,30 =20 /* Load the PTE */ @@ -428,8 +428,8 @@ interrupt_base: * kernel page tables. */ lis r11, PAGE_OFFSET@h - cmplw r10, r11 - blt+ 3f + cmplw cr7, r10, r11 + blt+ cr7, 3f lis r11, swapper_pg_dir@h ori r11, r11, swapper_pg_dir@l =20 @@ -515,6 +515,7 @@ interrupt_base: * r11 - PTE high word value * r12 - PTE low word value * r13 - TLB index + * cr7 - Result of comparison with PAGE_OFFSET * MMUCR - loaded with proper value when we get here * Upon exit, we reload everything and RFI. */ @@ -533,11 +534,10 @@ finish_tlb_load_44x: tlbwe r10,r13,PPC44x_TLB_PAGEID /* Write PAGEID */ =20 /* And WS 2 */ - li r10,0xf85 /* Mask to apply from PTE */ - rlwimi r10,r12,29,30,30 /* DIRTY -> SW position */ + li r10,0xf84 /* Mask to apply from PTE */ + rlwimi r10,r12,29,30,31 /* DIRTY,READ -> SW,SR position */ and r11,r12,r10 /* Mask PTE bits to keep */ - andi. r10,r12,_PAGE_USER /* User page ? */ - beq 1f /* nope, leave U bits empty */ + bge cr7,1f /* User page ? no, leave U bits empty */ rlwimi r11,r11,3,26,28 /* yes, copy S bits to U */ rlwinm r11,r11,0,~PPC44x_TLB_SX /* Clear SX if User page */ 1: tlbwe r11,r13,PPC44x_TLB_ATTRIB /* Write ATTRIB */ @@ -568,8 +568,8 @@ finish_tlb_load_44x: * kernel page tables. */ lis r11,PAGE_OFFSET@h - cmplw cr0,r10,r11 - blt+ 3f + cmplw cr7,r10,r11 + blt+ cr7,3f lis r11,swapper_pg_dir@h ori r11,r11, swapper_pg_dir@l li r12,0 /* MMUCR =3D 0 */ @@ -599,7 +599,7 @@ finish_tlb_load_44x: * place or can we save a couple of instructions here ? */ mfspr r12,SPRN_ESR - li r13,_PAGE_PRESENT|_PAGE_ACCESSED + li r13,_PAGE_PRESENT|_PAGE_ACCESSED|_PAGE_READ rlwimi r13,r12,10,30,30 =20 /* Load the PTE */ @@ -669,8 +669,8 @@ finish_tlb_load_44x: * kernel page tables. */ lis r11,PAGE_OFFSET@h - cmplw cr0,r10,r11 - blt+ 3f + cmplw cr7,r10,r11 + blt+ cr7,3f lis r11,swapper_pg_dir@h ori r11,r11, swapper_pg_dir@l li r12,0 /* MMUCR =3D 0 */ @@ -744,6 +744,7 @@ finish_tlb_load_44x: * r11 - PTE high word value * r12 - PTE low word value * r13 - free to use + * cr7 - Result of comparison with PAGE_OFFSET * MMUCR - loaded with proper value when we get here * Upon exit, we reload everything and RFI. */ @@ -753,11 +754,10 @@ finish_tlb_load_47x: tlbwe r11,r13,1 =20 /* And make up word 2 */ - li r10,0xf85 /* Mask to apply from PTE */ - rlwimi r10,r12,29,30,30 /* DIRTY -> SW position */ + li r10,0xf84 /* Mask to apply from PTE */ + rlwimi r10,r12,29,30,31 /* DIRTY,READ -> SW,SR position */ and r11,r12,r10 /* Mask PTE bits to keep */ - andi. r10,r12,_PAGE_USER /* User page ? */ - beq 1f /* nope, leave U bits empty */ + bge cr7,1f /* User page ? no, leave U bits empty */ rlwimi r11,r11,3,26,28 /* yes, copy S bits to U */ rlwinm r11,r11,0,~PPC47x_TLB2_SX /* Clear SX if User page */ 1: tlbwe r11,r13,2 --=20 2.41.0