From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751423AbbCDWxO (ORCPT ); Wed, 4 Mar 2015 17:53:14 -0500 Received: from terminus.zytor.com ([198.137.202.10]:41857 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750722AbbCDWxM (ORCPT ); Wed, 4 Mar 2015 17:53:12 -0500 Date: Wed, 4 Mar 2015 14:52:26 -0800 From: tip-bot for Denys Vlasenko Message-ID: Cc: bp@alien8.de, ast@plumgrid.com, luto@amacapital.net, dvlasenk@redhat.com, keescook@chromium.org, hpa@zytor.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, oleg@redhat.com, wad@chromium.org, fweisbec@gmail.com, mingo@kernel.org, torvalds@linux-foundation.org Reply-To: keescook@chromium.org, dvlasenk@redhat.com, hpa@zytor.com, ast@plumgrid.com, bp@alien8.de, luto@amacapital.net, mingo@kernel.org, fweisbec@gmail.com, torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, tglx@linutronix.de, oleg@redhat.com, wad@chromium.org In-Reply-To: <4c979ad604f0f02c5ade3b3da308b53eabd5e198.1424989793.git.luto@amacapital.net> References: <1420927210-19738-4-git-send-email-dvlasenk@redhat.com> <4c979ad604f0f02c5ade3b3da308b53eabd5e198.1424989793.git.luto@amacapital.net> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/asm] x86/asm/64: Open-code register save/ restore in trace_hardirqs*() thunks Git-Commit-ID: 69e8544cd0056e02965ffb5e8414fb7501a2ee2e 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 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 69e8544cd0056e02965ffb5e8414fb7501a2ee2e Gitweb: http://git.kernel.org/tip/69e8544cd0056e02965ffb5e8414fb7501a2ee2e Author: Denys Vlasenko AuthorDate: Thu, 26 Feb 2015 14:40:24 -0800 Committer: Ingo Molnar CommitDate: Wed, 4 Mar 2015 22:50:48 +0100 x86/asm/64: Open-code register save/restore in trace_hardirqs*() thunks This is a preparatory patch for change in "struct pt_regs" handling in entry_64.S. trace_hardirqs*() thunks were (ab)using a part of the 'pt_regs' handling code, namely the SAVE_ARGS/RESTORE_ARGS macros, to save/restore registers across C function calls. Since SAVE_ARGS is going to be changed, open-code register saving/restoring here. Incidentally, this removes a bit of dead code: one SAVE_ARGS was used just to emit a CFI annotation, but it also generated unreachable assembly instructions. Take a page from thunk_32.S and use push/pop instructions instead of movq, they are far shorter: 1 or 2 bytes versus 5, and no need for instructions to adjust %rsp: text data bss dec hex filename 333 40 0 373 175 thunk_64_movq.o 104 40 0 144 90 thunk_64_push_pop.o [ This is ugly as sin, but we'll fix up the ugliness in the next patch. I see no point in reordering patches just to avoid an ugly intermediate state. --Andy ] Signed-off-by: Denys Vlasenko Signed-off-by: Andy Lutomirski Cc: Alexei Starovoitov Cc: Borislav Petkov Cc: Frederic Weisbecker Cc: H. Peter Anvin Cc: Kees Cook Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Will Drewry Link: http://lkml.kernel.org/r/1420927210-19738-4-git-send-email-dvlasenk@redhat.com Link: http://lkml.kernel.org/r/4c979ad604f0f02c5ade3b3da308b53eabd5e198.1424989793.git.luto@amacapital.net Signed-off-by: Ingo Molnar --- arch/x86/lib/thunk_64.S | 46 ++++++++++++++++++++++++++++++++++++++++++---- 1 file changed, 42 insertions(+), 4 deletions(-) diff --git a/arch/x86/lib/thunk_64.S b/arch/x86/lib/thunk_64.S index b30b5eb..8ec443a 100644 --- a/arch/x86/lib/thunk_64.S +++ b/arch/x86/lib/thunk_64.S @@ -17,9 +17,27 @@ CFI_STARTPROC /* this one pushes 9 elems, the next one would be %rIP */ - SAVE_ARGS + pushq_cfi %rdi + CFI_REL_OFFSET rdi, 0 + pushq_cfi %rsi + CFI_REL_OFFSET rsi, 0 + pushq_cfi %rdx + CFI_REL_OFFSET rdx, 0 + pushq_cfi %rcx + CFI_REL_OFFSET rcx, 0 + pushq_cfi %rax + CFI_REL_OFFSET rax, 0 + pushq_cfi %r8 + CFI_REL_OFFSET r8, 0 + pushq_cfi %r9 + CFI_REL_OFFSET r9, 0 + pushq_cfi %r10 + CFI_REL_OFFSET r10, 0 + pushq_cfi %r11 + CFI_REL_OFFSET r11, 0 .if \put_ret_addr_in_rdi + /* 9*8(%rsp) is return addr on stack */ movq_cfi_restore 9*8, rdi .endif @@ -45,11 +63,31 @@ #endif #endif - /* SAVE_ARGS below is used only for the .cfi directives it contains. */ +#if defined(CONFIG_TRACE_IRQFLAGS) \ + || defined(CONFIG_DEBUG_LOCK_ALLOC) \ + || defined(CONFIG_PREEMPT) CFI_STARTPROC - SAVE_ARGS + CFI_ADJUST_CFA_OFFSET 9*8 restore: - RESTORE_ARGS + popq_cfi %r11 + CFI_RESTORE r11 + popq_cfi %r10 + CFI_RESTORE r10 + popq_cfi %r9 + CFI_RESTORE r9 + popq_cfi %r8 + CFI_RESTORE r8 + popq_cfi %rax + CFI_RESTORE rax + popq_cfi %rcx + CFI_RESTORE rcx + popq_cfi %rdx + CFI_RESTORE rdx + popq_cfi %rsi + CFI_RESTORE rsi + popq_cfi %rdi + CFI_RESTORE rdi ret CFI_ENDPROC _ASM_NOKPROBE(restore) +#endif