From nobody Tue Sep 16 16:01:09 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 E6C12C3DA7A for ; Mon, 2 Jan 2023 06:17:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230049AbjABGRn (ORCPT ); Mon, 2 Jan 2023 01:17:43 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53962 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229447AbjABGRm (ORCPT ); Mon, 2 Jan 2023 01:17:42 -0500 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 7BD4B10CB; Sun, 1 Jan 2023 22:17:40 -0800 (PST) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 8CFC32F4; Sun, 1 Jan 2023 22:18:21 -0800 (PST) Received: from a077893.blr.arm.com (unknown [10.162.40.15]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 706013F587; Sun, 1 Jan 2023 22:17:36 -0800 (PST) From: Anshuman Khandual To: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, catalin.marinas@arm.com, will@kernel.org Cc: lukas.bulwahn@gmail.com, james.morse@arm.com, suzuki.poulose@arm.com, Anshuman Khandual , Jonathan Corbet , Mark Rutland , linux-doc@vger.kernel.org Subject: [PATCH V4] arm64: errata: Workaround possible Cortex-A715 [ESR|FAR]_ELx corruption Date: Mon, 2 Jan 2023 11:46:51 +0530 Message-Id: <20230102061651.34745-1-anshuman.khandual@arm.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" If a Cortex-A715 cpu sees a page mapping permissions change from executable to non-executable, it may corrupt the ESR_ELx and FAR_ELx registers, on the next instruction abort caused by permission fault. Only user-space does executable to non-executable permission transition via mprotect() system call which calls ptep_modify_prot_start() and ptep_modify _prot_commit() helpers, while changing the page mapping. The platform code can override these helpers via __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION. Work around the problem via doing a break-before-make TLB invalidation, for all executable user space mappings, that go through mprotect() system call. This overrides ptep_modify_prot_start() and ptep_modify_prot_commit(), via defining HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION on the platform thus giving an opportunity to intercept user space exec mappings, and do the necessary TLB invalidation. Similar interceptions are also implemented for HugeTLB. Cc: Catalin Marinas Cc: Will Deacon Cc: Jonathan Corbet Cc: Mark Rutland Cc: linux-arm-kernel@lists.infradead.org Cc: linux-doc@vger.kernel.org Cc: linux-kernel@vger.kernel.org Reviewed-by: Catalin Marinas Signed-off-by: Anshuman Khandual --- This applies on v6.2-rc2. This has been tested on the model with 0x411FD4D1 as the MIDR_EL1 value for Cortex-A715, along with a non Cortex-A715 CPU as well, triggering both paths. Changes in V4: - Folded in CONFIG_ARM64_ERRATUM_2645198 related changes from Lukas Bulwahn https://lore.kernel.org/all/20221215094811.23188-1-lukas.bulwahn@gmail.com/ Changes in V3: https://lore.kernel.org/all/20221116140915.356601-3-anshuman.khandual@arm.c= om/ Documentation/arm64/silicon-errata.rst | 2 ++ arch/arm64/Kconfig | 16 ++++++++++++++++ arch/arm64/include/asm/hugetlb.h | 9 +++++++++ arch/arm64/include/asm/pgtable.h | 9 +++++++++ arch/arm64/kernel/cpu_errata.c | 7 +++++++ arch/arm64/mm/hugetlbpage.c | 21 +++++++++++++++++++++ arch/arm64/mm/mmu.c | 21 +++++++++++++++++++++ arch/arm64/tools/cpucaps | 1 + 8 files changed, 86 insertions(+) diff --git a/Documentation/arm64/silicon-errata.rst b/Documentation/arm64/s= ilicon-errata.rst index 808ade4cc008..ec5f889d7681 100644 --- a/Documentation/arm64/silicon-errata.rst +++ b/Documentation/arm64/silicon-errata.rst @@ -120,6 +120,8 @@ stable kernels. +----------------+-----------------+-----------------+--------------------= ---------+ | ARM | Cortex-A710 | #2224489 | ARM64_ERRATUM_22244= 89 | +----------------+-----------------+-----------------+--------------------= ---------+ +| ARM | Cortex-A715 | #2645198 | ARM64_ERRATUM_26451= 98 | ++----------------+-----------------+-----------------+--------------------= ---------+ | ARM | Cortex-X2 | #2119858 | ARM64_ERRATUM_21198= 58 | +----------------+-----------------+-----------------+--------------------= ---------+ | ARM | Cortex-X2 | #2224489 | ARM64_ERRATUM_22244= 89 | diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 03934808b2ed..cf6d1cd8b6dc 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -972,6 +972,22 @@ config ARM64_ERRATUM_2457168 =20 If unsure, say Y. =20 +config ARM64_ERRATUM_2645198 + bool "Cortex-A715: 2645198: Workaround possible [ESR|FAR]_ELx corruption" + default y + help + This option adds the workaround for ARM Cortex-A715 erratum 2645198. + + If a Cortex-A715 cpu sees a page mapping permissions change from execut= able + to non-executable, it may corrupt the ESR_ELx and FAR_ELx registers on = the + next instruction abort caused by permission fault. + + Only user-space does executable to non-executable permission transition= via + mprotect() system call. Workaround the problem by doing a break-before-= make + TLB invalidation, for all changes to executable user space mappings. + + If unsure, say Y. + config CAVIUM_ERRATUM_22375 bool "Cavium erratum 22375, 24313" default y diff --git a/arch/arm64/include/asm/hugetlb.h b/arch/arm64/include/asm/huge= tlb.h index d20f5da2d76f..6a4a1ab8eb23 100644 --- a/arch/arm64/include/asm/hugetlb.h +++ b/arch/arm64/include/asm/hugetlb.h @@ -49,6 +49,15 @@ extern pte_t huge_ptep_get(pte_t *ptep); =20 void __init arm64_hugetlb_cma_reserve(void); =20 +#define huge_ptep_modify_prot_start huge_ptep_modify_prot_start +extern pte_t huge_ptep_modify_prot_start(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep); + +#define huge_ptep_modify_prot_commit huge_ptep_modify_prot_commit +extern void huge_ptep_modify_prot_commit(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, + pte_t old_pte, pte_t new_pte); + #include =20 #endif /* __ASM_HUGETLB_H */ diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgta= ble.h index b4bbeed80fb6..6914add66bcf 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -1093,6 +1093,15 @@ static inline bool pud_sect_supported(void) } =20 =20 +#define __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION +#define ptep_modify_prot_start ptep_modify_prot_start +extern pte_t ptep_modify_prot_start(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep); + +#define ptep_modify_prot_commit ptep_modify_prot_commit +extern void ptep_modify_prot_commit(struct vm_area_struct *vma, + unsigned long addr, pte_t *ptep, + pte_t old_pte, pte_t new_pte); #endif /* !__ASSEMBLY__ */ =20 #endif /* __ASM_PGTABLE_H */ diff --git a/arch/arm64/kernel/cpu_errata.c b/arch/arm64/kernel/cpu_errata.c index 89ac00084f38..307faa2b4395 100644 --- a/arch/arm64/kernel/cpu_errata.c +++ b/arch/arm64/kernel/cpu_errata.c @@ -661,6 +661,13 @@ const struct arm64_cpu_capabilities arm64_errata[] =3D= { CAP_MIDR_RANGE_LIST(trbe_write_out_of_range_cpus), }, #endif +#ifdef CONFIG_ARM64_ERRATUM_2645198 + { + .desc =3D "ARM erratum 2645198", + .capability =3D ARM64_WORKAROUND_2645198, + ERRATA_MIDR_ALL_VERSIONS(MIDR_CORTEX_A715) + }, +#endif #ifdef CONFIG_ARM64_ERRATUM_2077057 { .desc =3D "ARM erratum 2077057", diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c index 35e9a468d13e..95364e8bdc19 100644 --- a/arch/arm64/mm/hugetlbpage.c +++ b/arch/arm64/mm/hugetlbpage.c @@ -559,3 +559,24 @@ bool __init arch_hugetlb_valid_size(unsigned long size) { return __hugetlb_valid_size(size); } + +pte_t huge_ptep_modify_prot_start(struct vm_area_struct *vma, unsigned lon= g addr, pte_t *ptep) +{ + if (IS_ENABLED(CONFIG_ARM64_ERRATUM_2645198) && + cpus_have_const_cap(ARM64_WORKAROUND_2645198)) { + /* + * Break-before-make (BBM) is required for all user space mappings + * when the permission changes from executable to non-executable + * in cases where cpu is affected with errata #2645198. + */ + if (pte_user_exec(READ_ONCE(*ptep))) + return huge_ptep_clear_flush(vma, addr, ptep); + } + return huge_ptep_get_and_clear(vma->vm_mm, addr, ptep); +} + +void huge_ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned lon= g addr, pte_t *ptep, + pte_t old_pte, pte_t pte) +{ + set_huge_pte_at(vma->vm_mm, addr, ptep, pte); +} diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index 14c87e8d69d8..d77c9f56b7b4 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -1630,3 +1630,24 @@ static int __init prevent_bootmem_remove_init(void) } early_initcall(prevent_bootmem_remove_init); #endif + +pte_t ptep_modify_prot_start(struct vm_area_struct *vma, unsigned long add= r, pte_t *ptep) +{ + if (IS_ENABLED(CONFIG_ARM64_ERRATUM_2645198) && + cpus_have_const_cap(ARM64_WORKAROUND_2645198)) { + /* + * Break-before-make (BBM) is required for all user space mappings + * when the permission changes from executable to non-executable + * in cases where cpu is affected with errata #2645198. + */ + if (pte_user_exec(READ_ONCE(*ptep))) + return ptep_clear_flush(vma, addr, ptep); + } + return ptep_get_and_clear(vma->vm_mm, addr, ptep); +} + +void ptep_modify_prot_commit(struct vm_area_struct *vma, unsigned long add= r, pte_t *ptep, + pte_t old_pte, pte_t pte) +{ + set_pte_at(vma->vm_mm, addr, ptep, pte); +} diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps index a86ee376920a..dfeb2c51e257 100644 --- a/arch/arm64/tools/cpucaps +++ b/arch/arm64/tools/cpucaps @@ -71,6 +71,7 @@ WORKAROUND_2038923 WORKAROUND_2064142 WORKAROUND_2077057 WORKAROUND_2457168 +WORKAROUND_2645198 WORKAROUND_2658417 WORKAROUND_TRBE_OVERWRITE_FILL_MODE WORKAROUND_TSB_FLUSH_FAILURE --=20 2.25.1