From patchwork Wed Dec 9 13:59:05 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vladimir Murzin X-Patchwork-Id: 11961591 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 937EFC19425 for ; Wed, 9 Dec 2020 14:01:13 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 54D2B23B42 for ; Wed, 9 Dec 2020 14:01:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 54D2B23B42 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-Id:Date: Subject:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=AMkgaxAOdHRmjAvjp5c/E1GvU1SrdDDx3WIAtCrC6y4=; b=xWCtUWVt4XpjiHN08WxXdT9pp 6wDygiu5eagkOfAP9vTqJ4HPVvghHiCt9QqqC9kN47vQUWk7nuVn7PBcp/QplCEOvYBq7e82/13U2 La3hcKnaB0IHFOjxjmj5jMg0o5686yQ0Oe5VBVL7RR52wMi6JSKznL0C7sNqjPpmDYxNEBHdaP5+3 WWu9uW9iyEtslWHHKFDo/yvzqgTFqFp9oZWAtxwkt+G4mvrIGsi0N0AjJ94pYs75SASR6+Q21+CAK A2b3XuNGX7nHjEX/8WS4pYInVABOy8zisHuEYUL+4kMrTJf+FGpJn0QLxZzkcSoRPi8EBaFDJPK9j Z91VoZ+4Q==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kn00K-0000RM-2b; Wed, 09 Dec 2020 13:59:40 +0000 Received: from foss.arm.com ([217.140.110.172]) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kn00C-0000PX-77 for linux-arm-kernel@lists.infradead.org; Wed, 09 Dec 2020 13:59:35 +0000 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 B7EE11042; Wed, 9 Dec 2020 05:59:27 -0800 (PST) Received: from login2.euhpc.arm.com (login2.euhpc.arm.com [10.6.27.34]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 115773F66B; Wed, 9 Dec 2020 05:59:26 -0800 (PST) From: Vladimir Murzin To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v2 1/2] arm64: Support execute-only permissions with Enhanced PAN Date: Wed, 9 Dec 2020 13:59:05 +0000 Message-Id: <20201209135906.39232-2-vladimir.murzin@arm.com> X-Mailer: git-send-email 2.24.0 In-Reply-To: <20201209135906.39232-1-vladimir.murzin@arm.com> References: <20201209135906.39232-1-vladimir.murzin@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201209_085932_412881_6484343D X-CRM114-Status: GOOD ( 18.88 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: catalin.marinas@arm.com, keescook@chromium.org, dave.martin@arm.com Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Enhanced Privileged Access Never (EPAN) allows Privileged Access Never to be used with Execute-only mappings. Absence of such support was a reason for 24cecc377463 ("arm64: Revert support for execute-only user mappings"). Thus now it can be revisited and re-enabled. Cc: Kees Cook Cc: Catalin Marinas Signed-off-by: Vladimir Murzin --- arch/arm64/Kconfig | 17 +++++++++++++++++ arch/arm64/include/asm/cpucaps.h | 3 ++- arch/arm64/include/asm/pgtable-prot.h | 5 +++-- arch/arm64/include/asm/pgtable.h | 14 +++++++++++++- arch/arm64/include/asm/sysreg.h | 3 ++- arch/arm64/kernel/cpufeature.c | 12 ++++++++++++ arch/arm64/mm/fault.c | 3 +++ 7 files changed, 52 insertions(+), 5 deletions(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 8d13b91..b1999a2 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1055,6 +1055,9 @@ config ARCH_WANT_HUGE_PMD_SHARE config ARCH_HAS_CACHE_LINE_SIZE def_bool y +config ARCH_HAS_FILTER_PGPROT + def_bool y + config ARCH_ENABLE_SPLIT_PMD_PTLOCK def_bool y if PGTABLE_LEVELS > 2 @@ -1669,6 +1672,20 @@ config ARM64_MTE endmenu +menu "ARMv8.7 architectural features" + +config ARM64_EPAN + bool "Enable support for Enhanced Privileged Access Never (EPAN)" + default y + depends on ARM64_PAN + help + Enhanced Privileged Access Never (EPAN) allows Privileged + Access Never to be used with Execute-only mappings. + + The feature is detected at runtime, and will remain disabled + if the cpu does not implement the feature. +endmenu + config ARM64_SVE bool "ARM Scalable Vector Extension support" default y diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h index a7242ef..a349cdd 100644 --- a/arch/arm64/include/asm/cpucaps.h +++ b/arch/arm64/include/asm/cpucaps.h @@ -65,7 +65,8 @@ #define ARM64_MTE 57 #define ARM64_WORKAROUND_1508412 58 #define ARM64_HAS_LDAPR 59 +#define ARM64_HAS_EPAN 60 -#define ARM64_NCAPS 60 +#define ARM64_NCAPS 61 #endif /* __ASM_CPUCAPS_H */ diff --git a/arch/arm64/include/asm/pgtable-prot.h b/arch/arm64/include/asm/pgtable-prot.h index 046be78..f91c2aa 100644 --- a/arch/arm64/include/asm/pgtable-prot.h +++ b/arch/arm64/include/asm/pgtable-prot.h @@ -88,12 +88,13 @@ extern bool arm64_use_ng_mappings; #define PAGE_SHARED_EXEC __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_RDONLY | PTE_NG | PTE_PXN | PTE_WRITE) #define PAGE_READONLY __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_RDONLY | PTE_NG | PTE_PXN | PTE_UXN) #define PAGE_READONLY_EXEC __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_RDONLY | PTE_NG | PTE_PXN) +#define PAGE_EXECONLY __pgprot(_PAGE_DEFAULT | PTE_RDONLY | PTE_NG | PTE_PXN) #define __P000 PAGE_NONE #define __P001 PAGE_READONLY #define __P010 PAGE_READONLY #define __P011 PAGE_READONLY -#define __P100 PAGE_READONLY_EXEC +#define __P100 PAGE_EXECONLY #define __P101 PAGE_READONLY_EXEC #define __P110 PAGE_READONLY_EXEC #define __P111 PAGE_READONLY_EXEC @@ -102,7 +103,7 @@ extern bool arm64_use_ng_mappings; #define __S001 PAGE_READONLY #define __S010 PAGE_SHARED #define __S011 PAGE_SHARED -#define __S100 PAGE_READONLY_EXEC +#define __S100 PAGE_EXECONLY #define __S101 PAGE_READONLY_EXEC #define __S110 PAGE_SHARED_EXEC #define __S111 PAGE_SHARED_EXEC diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h index 4ff12a7..e4ab9e0 100644 --- a/arch/arm64/include/asm/pgtable.h +++ b/arch/arm64/include/asm/pgtable.h @@ -114,7 +114,7 @@ extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)]; #define pte_valid(pte) (!!(pte_val(pte) & PTE_VALID)) #define pte_valid_not_user(pte) \ - ((pte_val(pte) & (PTE_VALID | PTE_USER)) == PTE_VALID) + ((pte_val(pte) & (PTE_VALID | PTE_USER | PTE_UXN)) == (PTE_VALID | PTE_UXN)) #define pte_valid_young(pte) \ ((pte_val(pte) & (PTE_VALID | PTE_AF)) == (PTE_VALID | PTE_AF)) #define pte_valid_user(pte) \ @@ -974,6 +974,18 @@ static inline bool arch_faults_on_old_pte(void) } #define arch_faults_on_old_pte arch_faults_on_old_pte +static inline pgprot_t arch_filter_pgprot(pgprot_t prot) +{ + if (cpus_have_const_cap(ARM64_HAS_EPAN)) + return prot; + + if (pgprot_val(prot) != pgprot_val(PAGE_EXECONLY)) + return prot; + + return PAGE_READONLY_EXEC; +} + + #endif /* !__ASSEMBLY__ */ #endif /* __ASM_PGTABLE_H */ diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h index 117bf97..48d379a 100644 --- a/arch/arm64/include/asm/sysreg.h +++ b/arch/arm64/include/asm/sysreg.h @@ -586,6 +586,7 @@ (SCTLR_EL2_RES1 | ENDIAN_SET_EL2) /* SCTLR_EL1 specific flags. */ +#define SCTLR_EL1_EPAN (BIT(57)) #define SCTLR_EL1_ATA0 (BIT(42)) #define SCTLR_EL1_TCF0_SHIFT 38 @@ -626,7 +627,7 @@ SCTLR_EL1_SED | SCTLR_ELx_I | SCTLR_EL1_DZE | SCTLR_EL1_UCT | \ SCTLR_EL1_NTWE | SCTLR_ELx_IESB | SCTLR_EL1_SPAN | SCTLR_ELx_ITFSB | \ SCTLR_ELx_ATA | SCTLR_EL1_ATA0 | ENDIAN_SET_EL1 | SCTLR_EL1_UCI | \ - SCTLR_EL1_RES1) + SCTLR_EL1_EPAN | SCTLR_EL1_RES1) /* MAIR_ELx memory attributes (used by Linux) */ #define MAIR_ATTR_DEVICE_nGnRnE UL(0x00) diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index cffcb01..f3e520c 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1746,6 +1746,18 @@ static const struct arm64_cpu_capabilities arm64_features[] = { .cpu_enable = cpu_enable_pan, }, #endif /* CONFIG_ARM64_PAN */ +#ifdef CONFIG_ARM64_EPAN + { + .desc = "Enhanced Privileged Access Never", + .capability = ARM64_HAS_EPAN, + .type = ARM64_CPUCAP_SYSTEM_FEATURE, + .matches = has_cpuid_feature, + .sys_reg = SYS_ID_AA64MMFR1_EL1, + .field_pos = ID_AA64MMFR1_PAN_SHIFT, + .sign = FTR_UNSIGNED, + .min_field_value = 3, + }, +#endif /* CONFIG_ARM64_EPAN */ #ifdef CONFIG_ARM64_LSE_ATOMICS { .desc = "LSE atomic instructions", diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index 8dc17e6..df21740 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -467,6 +467,9 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, if (faulthandler_disabled() || !mm) goto no_context; + if (cpus_have_const_cap(ARM64_HAS_EPAN)) + vm_flags &= ~VM_EXEC; + if (user_mode(regs)) mm_flags |= FAULT_FLAG_USER;