From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AIpwx4+u+jvtkmHcYo/jzRQLo97hpFZwjXUs2tQ5+FePbImOd1A8O3qMDa2pJZW4xmeBKE3IcDeK ARC-Seal: i=1; a=rsa-sha256; t=1523294039; cv=none; d=google.com; s=arc-20160816; b=MVrOyE3vF/WNCbp8dK7KGGoOGY093LhLIHlF9mQ7sQwguJwunAqyflcM1dYvG5Vb85 BzQxYBiAruc2O/t0MsC4yaIlP1kw1EyvRbksoR4KPj6D7QOqNxsRvrrWi6ycxP4mSM2F EXHN2SBTMc5tBJOKA3VOt/Fb0BR9HohTVtBgYQPtVKnRvkN7/kMq2PCsLHJIUmBxXdON 9t1lmRx9Tbn0eFNKvdT8vMD+SGBp71zcX1ahLBcnSQOeFf5vkGjcp6ARctud1ijpn3B3 pfxmeUdHpSVBNGNWJcGoVr6Wzaridn5Ofd3a0H3zMGIE05fYkU2LZkq6pJdlU/1+OFxJ VYQw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=precedence:content-disposition:content-transfer-encoding :mime-version:robot-unsubscribe:robot-id:git-commit-id:subject:to :references:in-reply-to:reply-to:cc:message-id:from:sender:date :arc-authentication-results; bh=xL5lc5tbaPWy9c82VEJPW6go5jdwFN791VHTn4KyIW0=; b=XrEIxcgCHoqQJdopFTl24vRQA/rmBbrOYaNF8CHsTrWxIcD+3xN7ax2EfmYyIxAAAx I4G5KJBBT1DCDxfnnmD1Cmb6HG7+98fcrE8QbQShu6EbVJkz+V99kYBubN/8kBv0H7Ny pO2ll2iZcWFdVzZoxriWd6t/eAsPERtc8PkREyr6Ase5GpFa9U2Q+LM/hi2IfceZ4e8A 3mMews18QpbHt85zxzOB09oB2BFK76wvztoa8eDVSGfwCdWZT9mtfFGcV2ED3NeBsv9m i0+7bNDB8tzti7f1HpDhhfenK63aMebl/OvKm1v7LBdlbZXT3rceCx/EdY2vdwel0rqe tUEg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of tipbot@zytor.com designates 198.137.202.136 as permitted sender) smtp.mailfrom=tipbot@zytor.com Authentication-Results: mx.google.com; spf=pass (google.com: domain of tipbot@zytor.com designates 198.137.202.136 as permitted sender) smtp.mailfrom=tipbot@zytor.com Date: Mon, 9 Apr 2018 10:13:17 -0700 Sender: tip tree robot From: tip-bot for Dave Hansen Message-ID: Cc: jpoimboe@redhat.com, torvalds@linux-foundation.org, dave.hansen@linux.intel.com, arjan@linux.intel.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, namit@vmware.com, bp@alien8.de, aarcange@redhat.com, luto@kernel.org, jgross@suse.com, keescook@google.com, gregkh@linuxfoundation.org, peterz@infradead.org, hpa@zytor.com, dan.j.williams@intel.com, hughd@google.com, mingo@kernel.org, dwmw2@infradead.org Reply-To: jgross@suse.com, keescook@google.com, hpa@zytor.com, peterz@infradead.org, gregkh@linuxfoundation.org, dwmw2@infradead.org, mingo@kernel.org, hughd@google.com, dan.j.williams@intel.com, dave.hansen@linux.intel.com, torvalds@linux-foundation.org, jpoimboe@redhat.com, linux-kernel@vger.kernel.org, arjan@linux.intel.com, luto@kernel.org, namit@vmware.com, aarcange@redhat.com, bp@alien8.de, tglx@linutronix.de In-Reply-To: <20180406205507.BCF4D4F0@viggo.jf.intel.com> References: <20180406205507.BCF4D4F0@viggo.jf.intel.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/pti] x86/espfix: Document use of _PAGE_GLOBAL Git-Commit-ID: 6baf4bec02dbc41645c3a5130ee15a8e1d62b80f X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1597289571344453428?= X-GMAIL-MSGID: =?utf-8?q?1597289571344453428?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: Commit-ID: 6baf4bec02dbc41645c3a5130ee15a8e1d62b80f Gitweb: https://git.kernel.org/tip/6baf4bec02dbc41645c3a5130ee15a8e1d62b80f Author: Dave Hansen AuthorDate: Fri, 6 Apr 2018 13:55:07 -0700 Committer: Ingo Molnar CommitDate: Mon, 9 Apr 2018 18:27:33 +0200 x86/espfix: Document use of _PAGE_GLOBAL The "normal" kernel page table creation mechanisms using PAGE_KERNEL_* page protections will never set _PAGE_GLOBAL with PTI. The few places in the kernel that always want _PAGE_GLOBAL must avoid using PAGE_KERNEL_*. Document that we want it here and its use is not accidental. Signed-off-by: Dave Hansen Cc: Andrea Arcangeli Cc: Andy Lutomirski Cc: Arjan van de Ven Cc: Borislav Petkov Cc: Dan Williams Cc: David Woodhouse Cc: Greg Kroah-Hartman Cc: Hugh Dickins Cc: Josh Poimboeuf Cc: Juergen Gross Cc: Kees Cook Cc: Linus Torvalds Cc: Nadav Amit Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/20180406205507.BCF4D4F0@viggo.jf.intel.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/espfix_64.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/x86/kernel/espfix_64.c b/arch/x86/kernel/espfix_64.c index e5ec3cafa72e..aebd0d5bc086 100644 --- a/arch/x86/kernel/espfix_64.c +++ b/arch/x86/kernel/espfix_64.c @@ -195,6 +195,10 @@ void init_espfix_ap(int cpu) pte_p = pte_offset_kernel(&pmd, addr); stack_page = page_address(alloc_pages_node(node, GFP_KERNEL, 0)); + /* + * __PAGE_KERNEL_* includes _PAGE_GLOBAL, which we want since + * this is mapped to userspace. + */ pte = __pte(__pa(stack_page) | ((__PAGE_KERNEL_RO | _PAGE_ENC) & ptemask)); for (n = 0; n < ESPFIX_PTE_CLONES; n++) set_pte(&pte_p[n*PTE_STRIDE], pte);