From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x2249HzsSm50g1+qFygkBX5c3I8wS2LpAjbcFGhguw+8IdSDsotuG3B46fvzo51bsPsqdsKw1 ARC-Seal: i=1; a=rsa-sha256; t=1519218599; cv=none; d=google.com; s=arc-20160816; b=ILO7p2ZuivH9VppLMRF1wUXitZWU8IH72fvZQXFdGPVTC2D6rFMeijlPWV1KXPmpI5 uhmfatJxXi4Z7IbHCSpXHeRm4eSwARBnef321cAQryBdlhQ+6H7M/yN7s6AsJUzsC7Rf r05RElyhmeABzw2zC+7j13Wh40sZDPLDv5ehFehdPX8XKSFNdmI0tujpANSrXM5Azhye p6XZ42c3WDAeEq/u6pndpdO4iDZCEyPTWf6XS1KCjX/rJTlRX9EysdB1BjSglQZrQe8R ynUba2TNTwUKnrOifFnd8gVgZZrg/K4B1b39OkALXFO6y/2gC2e2gP0LkvEKhX0AHqwl TgQw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=h+rh9CtVQJhNQgA4EZMv1G6FmaI1rCqNbJlzrISOHMY=; b=ibwIGZe9xftwcfXlSG83VoOamS1y+X1gDA9y8DFmVFaTptVbF6zujHdd+TqPmyisSS wbZ0bgVm6TVCu3uFEHeKXYDMztCN2JTvfhiY5eVQm57huewgkBEDiMxzC8+N0YdTpBp9 S8wyyXwkNcoLdiTGlTz2tvg/jRcGFk4IQZspJ9EXnle/2lyj0GCK9BbVYpkBhTqTYgiu 7zlsNLia7AXpx45HEqCqCxrbRGZJdEpWjbAJxF9b5dYGJ+4fC+FZJ/nG8eOBN3dtZRkz VCvucq0HHjUA0kDzxeUwjbgW2+d6SVsIgq+Lcw7p5NIWCPKDRUWe9ggtuEdkWJNxYSi1 D+Lw== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.71.90 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.71.90 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Linus Torvalds , Dominik Brodowski , Andy Lutomirski , Borislav Petkov , Brian Gerst , Denys Vlasenko , "H. Peter Anvin" , Josh Poimboeuf , Peter Zijlstra , Thomas Gleixner , dan.j.williams@intel.com, Ingo Molnar Subject: [PATCH 4.15 062/163] x86/entry/64: Introduce the PUSH_AND_CLEAN_REGS macro Date: Wed, 21 Feb 2018 13:48:11 +0100 Message-Id: <20180221124533.890417390@linuxfoundation.org> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180221124529.931834518@linuxfoundation.org> References: <20180221124529.931834518@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1593015562439488858?= X-GMAIL-MSGID: =?utf-8?q?1593016161935127665?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dominik Brodowski commit 3f01daecd545e818098d84fd1ad43e19a508d705 upstream. Those instances where ALLOC_PT_GPREGS_ON_STACK is called just before SAVE_AND_CLEAR_REGS can trivially be replaced by PUSH_AND_CLEAN_REGS. This macro uses PUSH instead of MOV and should therefore be faster, at least on newer CPUs. Suggested-by: Linus Torvalds Signed-off-by: Dominik Brodowski Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: dan.j.williams@intel.com Link: http://lkml.kernel.org/r/20180211104949.12992-5-linux@dominikbrodowski.net Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- arch/x86/entry/calling.h | 36 ++++++++++++++++++++++++++++++++++++ arch/x86/entry/entry_64.S | 6 ++---- 2 files changed, 38 insertions(+), 4 deletions(-) --- a/arch/x86/entry/calling.h +++ b/arch/x86/entry/calling.h @@ -137,6 +137,42 @@ For 32-bit we have the following convent UNWIND_HINT_REGS offset=\offset .endm + .macro PUSH_AND_CLEAR_REGS + /* + * Push registers and sanitize registers of values that a + * speculation attack might otherwise want to exploit. The + * lower registers are likely clobbered well before they + * could be put to use in a speculative execution gadget. + * Interleave XOR with PUSH for better uop scheduling: + */ + pushq %rdi /* pt_regs->di */ + pushq %rsi /* pt_regs->si */ + pushq %rdx /* pt_regs->dx */ + pushq %rcx /* pt_regs->cx */ + pushq %rax /* pt_regs->ax */ + pushq %r8 /* pt_regs->r8 */ + xorq %r8, %r8 /* nospec r8 */ + pushq %r9 /* pt_regs->r9 */ + xorq %r9, %r9 /* nospec r9 */ + pushq %r10 /* pt_regs->r10 */ + xorq %r10, %r10 /* nospec r10 */ + pushq %r11 /* pt_regs->r11 */ + xorq %r11, %r11 /* nospec r11*/ + pushq %rbx /* pt_regs->rbx */ + xorl %ebx, %ebx /* nospec rbx*/ + pushq %rbp /* pt_regs->rbp */ + xorl %ebp, %ebp /* nospec rbp*/ + pushq %r12 /* pt_regs->r12 */ + xorq %r12, %r12 /* nospec r12*/ + pushq %r13 /* pt_regs->r13 */ + xorq %r13, %r13 /* nospec r13*/ + pushq %r14 /* pt_regs->r14 */ + xorq %r14, %r14 /* nospec r14*/ + pushq %r15 /* pt_regs->r15 */ + xorq %r15, %r15 /* nospec r15*/ + UNWIND_HINT_REGS + .endm + .macro POP_REGS pop_rdi=1 skip_r11rcx=0 popq %r15 popq %r14 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -564,8 +564,7 @@ END(irq_entries_start) call switch_to_thread_stack 1: - ALLOC_PT_GPREGS_ON_STACK - SAVE_AND_CLEAR_REGS + PUSH_AND_CLEAR_REGS ENCODE_FRAME_POINTER testb $3, CS(%rsp) @@ -1112,8 +1111,7 @@ ENTRY(xen_failsafe_callback) addq $0x30, %rsp UNWIND_HINT_IRET_REGS pushq $-1 /* orig_ax = -1 => not a system call */ - ALLOC_PT_GPREGS_ON_STACK - SAVE_AND_CLEAR_REGS + PUSH_AND_CLEAR_REGS ENCODE_FRAME_POINTER jmp error_exit END(xen_failsafe_callback)