From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx4/S+uK68pEuIcARoBFUfyjr/RDRgujRta33qTtm/JcxH8YeQgUvfTCOKkclGZs2dqlIFncX ARC-Seal: i=1; a=rsa-sha256; t=1524498476; cv=none; d=google.com; s=arc-20160816; b=d3Iajh5gGhJRAj9Km1XfOGJN/EWK+mhvyRNEAAwxuO0ZtLBWJjM89eMYPuoVddHHNQ CMdYzAnL67YBrCwQvAqYxY1uhO8kN1HnIUhv7NKYsrLzUqQbk5p262r2j4nbXH7czcTp x0N9Q+7nyiQm4JygHVMnlVK2G8EkCpXUsUX8yOMOfSIQrionmgQ7VkizTGFuWrfkGRx9 a2yvjMWjufIOrOHprbBz8EZs0l/bzzzpaIACpU3eM04N3nO0Hx5+KyV83CAZwjF674Oy WOv1JqPBNhxij/9O4MBjtgai/I8H+JhBNhZgqRW3nofiD4W94jMYk4E63hTerBputAAf AjAA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature:arc-authentication-results; bh=AkL2T1gFHrvbc/GzjpwIwKONVsdxG+I5UvQKry0B44A=; b=AYJrfoyu877sHDbPUqGUsOWMz18xSCmkF8ruDIzW/zT2nLva26LApprEZCqCFeNCWN 3Ji7hbFoiU//sfR2hH2vsOsARD4yZeFF+tIMRLwQuOSxYH610H3NoTwgx6NaIi3gMfbH JTCpqFRdXYBbFv361MYykUGUdhr2+PJrRwxCcsQtXeZu+5tFGZE2CKQvb7M1W2zhfFNw x0ATqktwTyM5KEWZmUHyylPv8XLNPskPLYbmwt/5UeA6XCpmi7WfKwXMusdxDY35Wnol HWnDLZmvbXy10AvMgFDWDYXfPDyv1LfVQ4O2MrgttOUeXvSKYVREZZ9KdmmwdzrPV7VP yf0A== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass (test mode) header.i=@8bytes.org header.s=mail-1 header.b=g7eBR9dz; spf=pass (google.com: domain of joro@8bytes.org designates 81.169.241.247 as permitted sender) smtp.mailfrom=joro@8bytes.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=8bytes.org Authentication-Results: mx.google.com; dkim=pass (test mode) header.i=@8bytes.org header.s=mail-1 header.b=g7eBR9dz; spf=pass (google.com: domain of joro@8bytes.org designates 81.169.241.247 as permitted sender) smtp.mailfrom=joro@8bytes.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=8bytes.org From: Joerg Roedel To: Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" Cc: x86@kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, Linus Torvalds , Andy Lutomirski , Dave Hansen , Josh Poimboeuf , Juergen Gross , Peter Zijlstra , Borislav Petkov , Jiri Kosina , Boris Ostrovsky , Brian Gerst , David Laight , Denys Vlasenko , Eduardo Valentin , Greg KH , Will Deacon , aliguori@amazon.com, daniel.gruss@iaik.tugraz.at, hughd@google.com, keescook@google.com, Andrea Arcangeli , Waiman Long , Pavel Machek , "David H . Gutteridge" , jroedel@suse.de, joro@8bytes.org Subject: [PATCH 27/37] x86/mm/pti: Keep permissions when cloning kernel text in pti_clone_kernel_text() Date: Mon, 23 Apr 2018 17:47:30 +0200 Message-Id: <1524498460-25530-28-git-send-email-joro@8bytes.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1524498460-25530-1-git-send-email-joro@8bytes.org> References: <1524498460-25530-1-git-send-email-joro@8bytes.org> X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1598552515043565489?= X-GMAIL-MSGID: =?utf-8?q?1598552515043565489?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: From: Joerg Roedel Mapping the kernel text area to user-space makes only sense if it has the same permissions as in the kernel page-table. If permissions are different this will cause a TLB reload when using the kernel page-table, which is as good as not mapping it at all. On 64-bit kernels this patch makes no difference, as the whole range cloned by pti_clone_kernel_text() is mapped RO anyway. On 32 bit there are writeable mappings in the range, so just keep the permissions as they are. Signed-off-by: Joerg Roedel --- arch/x86/mm/pti.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c index 9cceae3..e3059bb0 100644 --- a/arch/x86/mm/pti.c +++ b/arch/x86/mm/pti.c @@ -460,7 +460,7 @@ void pti_clone_kernel_text(void) if (!pti_kernel_image_global_ok()) return; - pti_clone_pmds(start, end, _PAGE_RW); + pti_clone_pmds(start, end, 0); } /* -- 2.7.4