From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-2898263-1519909635-5-7959769409441574029 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.249, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES ensv, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='CN', FromHeader='org', MailFrom='org' X-Spam-charsets: X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1519909635; b=lk+/6II6Fy4bcBgONcaavCPeY3AJc5HpU+jE2bVvM/n1oNE 7fRoNP+M5qwj6+v7Asjz8hvRoToXUfp82irigu6OXMQnPjaav7CoFqPWlzAij3WB yV9QjAy2iFgy2p5klSBF2JOhud3pbCley65D1OxQIVoQXboq2IqOCodrf4renFb2 ohD6M5e9ED9SZqx/EjXdEORLV9ALfQV4AQ/kHaqa3reINkdDc94NfGia9entGRi+ l9vUtnlzxTMiF4jN1E2CQLr7VC6zH/uzDatOd6T5Qxn1p+rR6kWbpbmowiOVIR+q qFSaQbqlItWOebh9MxSb7zrf/TC0/VwJkPhOT7g== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id :in-reply-to:references:sender:list-id; s=arctest; t=1519909635; bh=B06UrOpFOhDhk8CXgd0QbaeXaNIGUHvFPN317fRlFQ4=; b=XxrFJTrCkr89 tRD3Ya3Yy8Ij6w9Sgif5YsPEc6YduiqaNcN0ejJuMdq2GWpVNODFUKFZ66uHbF7l hbylxCW2FcscsyPfIZUqFmYK8wvwTn25Mv5fqzWhyOSxtnPuFdkkTQQfKhvUVzIy WwCwJtiNjzwvM7FYvHIoVpvU3vvBJMsRFY3KLpmjOYimxn74FulbPIiTceBQ9LDD EAAqjmbvumY5ohNqgnOeIfOhoxr9/gZ0SleGCrcPHBp2UgEnrv2jAW+8amNqzVlI cvUsaGONyxP+2TVak8rNe7Jqwcg5mGxEBLwNrrdOTl7KdnYd7lFnRLjlVgcKUt1o HnhA23/Vjg== ARC-Authentication-Results: i=1; mx2.messagingengine.com; arc=none (no signatures found); dkim=pass (1024-bit rsa key sha256) header.d=linaro.org header.i=@linaro.org header.b=D/+FhXt5 x-bits=1024 x-keytype=rsa x-algorithm=sha256 x-selector=google; dmarc=pass (p=none,has-list-id=yes,d=none) header.from=linaro.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-google-dkim=pass (2048-bit rsa key) header.d=1e100.net header.i=@1e100.net header.b=j264OKcz; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linaro.org header.result=pass header_is_org_domain=yes Authentication-Results: mx2.messagingengine.com; arc=none (no signatures found); dkim=pass (1024-bit rsa key sha256) header.d=linaro.org header.i=@linaro.org header.b=D/+FhXt5 x-bits=1024 x-keytype=rsa x-algorithm=sha256 x-selector=google; dmarc=pass (p=none,has-list-id=yes,d=none) header.from=linaro.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-google-dkim=pass (2048-bit rsa key) header.d=1e100.net header.i=@1e100.net header.b=j264OKcz; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linaro.org header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030791AbeCAM5J (ORCPT ); Thu, 1 Mar 2018 07:57:09 -0500 Received: from mail-pg0-f66.google.com ([74.125.83.66]:41327 "EHLO mail-pg0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030789AbeCAM5C (ORCPT ); Thu, 1 Mar 2018 07:57:02 -0500 X-Google-Smtp-Source: AG47ELsj8/N9BmPe04eqb9FPvC24xYKDpVP8wgcHlRMGFnwC+82inZWq/GwfEgDId/anSFRAIo99yA== From: Alex Shi To: Marc Zyngier , Will Deacon , Ard Biesheuvel , Catalin Marinas , stable@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Alex Shi Subject: [PATCH 14/45] arm64: uaccess: Don't bother eliding access_ok checks in __{get, put}_user Date: Thu, 1 Mar 2018 20:53:51 +0800 Message-Id: <1519908862-11425-15-git-send-email-alex.shi@linaro.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1519908862-11425-1-git-send-email-alex.shi@linaro.org> References: <1519908862-11425-1-git-send-email-alex.shi@linaro.org> Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: From: Will Deacon commit 84624087dd7e upstream. access_ok isn't an expensive operation once the addr_limit for the current thread has been loaded into the cache. Given that the initial access_ok check preceding a sequence of __{get,put}_user operations will take the brunt of the miss, we can make the __* variants identical to the full-fat versions, which brings with it the benefits of address masking. The likely cost in these sequences will be from toggling PAN/UAO, which we can address later by implementing the *_unsafe versions. Reviewed-by: Robin Murphy Signed-off-by: Will Deacon Signed-off-by: Catalin Marinas Signed-off-by: Alex Shi --- arch/arm64/include/asm/uaccess.h | 54 ++++++++++++++++++++++++---------------- 1 file changed, 32 insertions(+), 22 deletions(-) diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index 00025c5..ffa4e39 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -248,30 +248,35 @@ do { \ (x) = (__force __typeof__(*(ptr)))__gu_val; \ } while (0) -#define __get_user(x, ptr) \ +#define __get_user_check(x, ptr, err) \ ({ \ - int __gu_err = 0; \ - __get_user_err((x), (ptr), __gu_err); \ - __gu_err; \ + __typeof__(*(ptr)) __user *__p = (ptr); \ + might_fault(); \ + if (access_ok(VERIFY_READ, __p, sizeof(*__p))) { \ + __p = uaccess_mask_ptr(__p); \ + __get_user_err((x), __p, (err)); \ + } else { \ + (x) = 0; (err) = -EFAULT; \ + } \ }) #define __get_user_error(x, ptr, err) \ ({ \ - __get_user_err((x), (ptr), (err)); \ + __get_user_check((x), (ptr), (err)); \ (void)0; \ }) #define __get_user_unaligned __get_user -#define get_user(x, ptr) \ +#define __get_user(x, ptr) \ ({ \ - __typeof__(*(ptr)) __user *__p = (ptr); \ - might_fault(); \ - access_ok(VERIFY_READ, __p, sizeof(*__p)) ? \ - __p = uaccess_mask_ptr(__p), __get_user((x), __p) : \ - ((x) = 0, -EFAULT); \ + int __gu_err = 0; \ + __get_user_check((x), (ptr), __gu_err); \ + __gu_err; \ }) +#define get_user __get_user + #define __put_user_asm(instr, alt_instr, reg, x, addr, err, feature) \ asm volatile( \ "1:"ALTERNATIVE(instr " " reg "1, [%2]\n", \ @@ -314,30 +319,35 @@ do { \ uaccess_disable_not_uao(); \ } while (0) -#define __put_user(x, ptr) \ +#define __put_user_check(x, ptr, err) \ ({ \ - int __pu_err = 0; \ - __put_user_err((x), (ptr), __pu_err); \ - __pu_err; \ + __typeof__(*(ptr)) __user *__p = (ptr); \ + might_fault(); \ + if (access_ok(VERIFY_WRITE, __p, sizeof(*__p))) { \ + __p = uaccess_mask_ptr(__p); \ + __put_user_err((x), __p, (err)); \ + } else { \ + (err) = -EFAULT; \ + } \ }) #define __put_user_error(x, ptr, err) \ ({ \ - __put_user_err((x), (ptr), (err)); \ + __put_user_check((x), (ptr), (err)); \ (void)0; \ }) #define __put_user_unaligned __put_user -#define put_user(x, ptr) \ +#define __put_user(x, ptr) \ ({ \ - __typeof__(*(ptr)) __user *__p = (ptr); \ - might_fault(); \ - access_ok(VERIFY_WRITE, __p, sizeof(*__p)) ? \ - __p = uaccess_mask_ptr(__p), __put_user((x), __p) : \ - -EFAULT; \ + int __pu_err = 0; \ + __put_user_check((x), (ptr), __pu_err); \ + __pu_err; \ }) +#define put_user __put_user + extern unsigned long __must_check __arch_copy_from_user(void *to, const void __user *from, unsigned long n); extern unsigned long __must_check __arch_copy_to_user(void __user *to, const void *from, unsigned long n); extern unsigned long __must_check __copy_in_user(void __user *to, const void __user *from, unsigned long n); -- 2.7.4