From mboxrd@z Thu Jan 1 00:00:00 1970 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=-12.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 BF09FC4742C for ; Fri, 13 Nov 2020 12:53:35 +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 5A091206D9 for ; Fri, 13 Nov 2020 12:53:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="h7X9k7CW" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5A091206D9 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:MIME-Version:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id: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=CUqKhRrPRtv2Jjw2+5Vv+RxArG6eVpsKZuaGipCdstk=; b=h7X9k7CWsX4FhTDSNoGyCyBPko AB2fmufnoU/HRJz7PQx9mB8x4822xuTyeQs1xLLe2I8BG1N08sDw4j4AskptIvFCoNavxnbt4sVUC 9r4yIMA+2efsOVhyzPwp8X5pAXFoaLa/E+ZGL1golM6Q/IeQDUdjXphaqkcW0Qtmck9daadVw6J1w ClaofNsYICKxNV5xc3JTQD7TorlbyLP125JdRw2Ry6ttK0aN3H7jCguL4EhN+KU7Vs0tREsbibrju 8SOS3K7xHFl7O2gWerwPhV8T3MfsDlz5aKt1tfz85a7xNl+LF72txOTQLQvpMrZbZZcPrUCohBT/9 Va4maKDA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kdYYj-0007Ja-DT; Fri, 13 Nov 2020 12:52:09 +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 1kdYWp-0006Jt-8R for linux-arm-kernel@lists.infradead.org; Fri, 13 Nov 2020 12:50:15 +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 BE93016F8; Fri, 13 Nov 2020 04:50:10 -0800 (PST) Received: from lakrids.cambridge.arm.com (usa-sjc-imap-foss1.foss.arm.com [10.121.207.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id BF2633F6CF; Fri, 13 Nov 2020 04:50:09 -0800 (PST) From: Mark Rutland To: linux-arm-kernel@lists.infradead.org, catalin.marinas@arm.com, will@kernel.org Subject: [PATCHv4 16/17] arm64: uaccess: remove redundant PAN toggling Date: Fri, 13 Nov 2020 12:49:36 +0000 Message-Id: <20201113124937.20574-17-mark.rutland@arm.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20201113124937.20574-1-mark.rutland@arm.com> References: <20201113124937.20574-1-mark.rutland@arm.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201113_075011_471754_C850DB6B X-CRM114-Status: GOOD ( 17.75 ) 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: mark.rutland@arm.com, robin.murphy@arm.com, james.morse@arm.com, hch@lst.de MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Some code (e.g. futex) needs to make privileged accesses to userspace memory, and uses uaccess_{enable,disable}_privileged() in order to permit this. All other uaccess primitives use LDTR/STTR, and never need to toggle PAN. Remove the redundant PAN toggling. Signed-off-by: Mark Rutland Cc: Catalin Marinas Cc: Christoph Hellwig Cc: James Morse Cc: Will Deacon --- arch/arm64/include/asm/cpucaps.h | 1 - arch/arm64/include/asm/uaccess.h | 59 +++++++++++++--------------------------- arch/arm64/kernel/cpufeature.c | 17 ------------ 3 files changed, 19 insertions(+), 58 deletions(-) diff --git a/arch/arm64/include/asm/cpucaps.h b/arch/arm64/include/asm/cpucaps.h index e7d98997c09c..ce7b7ada2c82 100644 --- a/arch/arm64/include/asm/cpucaps.h +++ b/arch/arm64/include/asm/cpucaps.h @@ -17,7 +17,6 @@ #define ARM64_WORKAROUND_834220 7 #define ARM64_HAS_NO_HW_PREFETCH 8 #define ARM64_HAS_UAO 9 -#define ARM64_ALT_PAN_NOT_UAO 10 #define ARM64_HAS_VIRT_HOST_EXTN 11 #define ARM64_WORKAROUND_CAVIUM_27456 12 #define ARM64_HAS_32BIT_EL0 13 diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index 8a4d9ed5eb51..d81c083967ed 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -159,41 +159,20 @@ static inline void __uaccess_enable_hw_pan(void) CONFIG_ARM64_PAN)); } -#define __uaccess_disable(alt) \ -do { \ - if (!uaccess_ttbr0_disable()) \ - asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), alt, \ - CONFIG_ARM64_PAN)); \ -} while (0) - -#define __uaccess_enable(alt) \ -do { \ - if (!uaccess_ttbr0_enable()) \ - asm(ALTERNATIVE("nop", SET_PSTATE_PAN(0), alt, \ - CONFIG_ARM64_PAN)); \ -} while (0) - static inline void uaccess_disable_privileged(void) { - __uaccess_disable(ARM64_HAS_PAN); -} + if (uaccess_ttbr0_disable()) + return; -static inline void uaccess_enable_privileged(void) -{ - __uaccess_enable(ARM64_HAS_PAN); + __uaccess_enable_hw_pan(); } -/* - * These functions are no-ops when UAO is present. - */ -static inline void uaccess_disable_not_uao(void) +static inline void uaccess_enable_privileged(void) { - __uaccess_disable(ARM64_ALT_PAN_NOT_UAO); -} + if (uaccess_ttbr0_enable()) + return; -static inline void uaccess_enable_not_uao(void) -{ - __uaccess_enable(ARM64_ALT_PAN_NOT_UAO); + __uaccess_disable_hw_pan(); } /* @@ -265,9 +244,9 @@ do { \ #define __raw_get_user(x, ptr, err) \ do { \ __chk_user_ptr(ptr); \ - uaccess_enable_not_uao(); \ + uaccess_ttbr0_enable(); \ __raw_get_mem("ldtr", x, ptr, err); \ - uaccess_disable_not_uao(); \ + uaccess_ttbr0_disable(); \ } while (0) #define __get_user_error(x, ptr, err) \ @@ -338,9 +317,9 @@ do { \ #define __raw_put_user(x, ptr, err) \ do { \ __chk_user_ptr(ptr); \ - uaccess_enable_not_uao(); \ + uaccess_ttbr0_enable(); \ __raw_put_mem("sttr", x, ptr, err); \ - uaccess_disable_not_uao(); \ + uaccess_ttbr0_disable(); \ } while (0) #define __put_user_error(x, ptr, err) \ @@ -378,10 +357,10 @@ extern unsigned long __must_check __arch_copy_from_user(void *to, const void __u #define raw_copy_from_user(to, from, n) \ ({ \ unsigned long __acfu_ret; \ - uaccess_enable_not_uao(); \ + uaccess_ttbr0_enable(); \ __acfu_ret = __arch_copy_from_user((to), \ __uaccess_mask_ptr(from), (n)); \ - uaccess_disable_not_uao(); \ + uaccess_ttbr0_disable(); \ __acfu_ret; \ }) @@ -389,10 +368,10 @@ extern unsigned long __must_check __arch_copy_to_user(void __user *to, const voi #define raw_copy_to_user(to, from, n) \ ({ \ unsigned long __actu_ret; \ - uaccess_enable_not_uao(); \ + uaccess_ttbr0_enable(); \ __actu_ret = __arch_copy_to_user(__uaccess_mask_ptr(to), \ (from), (n)); \ - uaccess_disable_not_uao(); \ + uaccess_ttbr0_disable(); \ __actu_ret; \ }) @@ -400,10 +379,10 @@ extern unsigned long __must_check __arch_copy_in_user(void __user *to, const voi #define raw_copy_in_user(to, from, n) \ ({ \ unsigned long __aciu_ret; \ - uaccess_enable_not_uao(); \ + uaccess_ttbr0_enable(); \ __aciu_ret = __arch_copy_in_user(__uaccess_mask_ptr(to), \ __uaccess_mask_ptr(from), (n)); \ - uaccess_disable_not_uao(); \ + uaccess_ttbr0_disable(); \ __aciu_ret; \ }) @@ -414,9 +393,9 @@ extern unsigned long __must_check __arch_clear_user(void __user *to, unsigned lo static inline unsigned long __must_check __clear_user(void __user *to, unsigned long n) { if (access_ok(to, n)) { - uaccess_enable_not_uao(); + uaccess_ttbr0_enable(); n = __arch_clear_user(__uaccess_mask_ptr(to), n); - uaccess_disable_not_uao(); + uaccess_ttbr0_disable(); } return n; } diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 5e9732f3561e..5d7032625ff2 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -153,10 +153,6 @@ EXPORT_SYMBOL(cpu_hwcap_keys); .width = 0, \ } -/* meta feature for alternatives */ -static bool __maybe_unused -cpufeature_pan_not_uao(const struct arm64_cpu_capabilities *entry, int __unused); - static void cpu_enable_cnp(struct arm64_cpu_capabilities const *cap); static bool __system_matches_cap(unsigned int n); @@ -1779,13 +1775,6 @@ static const struct arm64_cpu_capabilities arm64_features[] = { .min_field_value = 1, }, #endif /* CONFIG_ARM64_UAO */ -#ifdef CONFIG_ARM64_PAN - { - .capability = ARM64_ALT_PAN_NOT_UAO, - .type = ARM64_CPUCAP_SYSTEM_FEATURE, - .matches = cpufeature_pan_not_uao, - }, -#endif /* CONFIG_ARM64_PAN */ #ifdef CONFIG_ARM64_VHE { .desc = "Virtualization Host Extensions", @@ -2726,12 +2715,6 @@ void __init setup_cpu_features(void) ARCH_DMA_MINALIGN); } -static bool __maybe_unused -cpufeature_pan_not_uao(const struct arm64_cpu_capabilities *entry, int __unused) -{ - return (__system_matches_cap(ARM64_HAS_PAN) && !__system_matches_cap(ARM64_HAS_UAO)); -} - static void __maybe_unused cpu_enable_cnp(struct arm64_cpu_capabilities const *cap) { cpu_replace_ttbr1(lm_alias(swapper_pg_dir)); -- 2.11.0 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel