From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756163AbaHHRp4 (ORCPT ); Fri, 8 Aug 2014 13:45:56 -0400 Received: from mx1.redhat.com ([209.132.183.28]:29219 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753721AbaHHRpy (ORCPT ); Fri, 8 Aug 2014 13:45:54 -0400 From: Denys Vlasenko To: linux-kernel@vger.kernel.org Cc: Denys Vlasenko , Linus Torvalds , Oleg Nesterov , "H. Peter Anvin" , Andy Lutomirski , Frederic Weisbecker , X86 ML , Alexei Starovoitov , Will Drewry , Kees Cook Subject: [PATCH 13/17] x86: ia32entry.S: fold IA32_ARG_FIXUP macro into its callers Date: Fri, 8 Aug 2014 19:44:36 +0200 Message-Id: <1407519880-6719-14-git-send-email-dvlasenk@redhat.com> In-Reply-To: <1407519880-6719-1-git-send-email-dvlasenk@redhat.com> References: <1407519880-6719-1-git-send-email-dvlasenk@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Use of a small macro - one with conditional expansion - does more harm than good. It obfuscates code, with minimal code reuse. For example, because of obfuscation it's not obvious that in ia32_sysenter_target, we can optimize loading of r9 - currently it is loaded with a detour through ebp. This patch folds IA32_ARG_FIXUP macro into its callers. No code changes. Signed-off-by: Denys Vlasenko CC: Linus Torvalds CC: Oleg Nesterov CC: "H. Peter Anvin" CC: Andy Lutomirski CC: Frederic Weisbecker CC: X86 ML CC: Alexei Starovoitov CC: Will Drewry CC: Kees Cook CC: linux-kernel@vger.kernel.org --- arch/x86/ia32/ia32entry.S | 32 ++++++++++++++++++-------------- 1 file changed, 18 insertions(+), 14 deletions(-) diff --git a/arch/x86/ia32/ia32entry.S b/arch/x86/ia32/ia32entry.S index 8cd08de..c70c9a0 100644 --- a/arch/x86/ia32/ia32entry.S +++ b/arch/x86/ia32/ia32entry.S @@ -30,17 +30,6 @@ .section .entry.text, "ax" - .macro IA32_ARG_FIXUP noebp=0 - movl %edi,%r8d - .if \noebp - .else - movl %ebp,%r9d - .endif - xchg %ecx,%esi - movl %ebx,%edi - movl %edx,%edx /* zero extension */ - .endm - /* clobbers %rax */ .macro CLEAR_RREGS _r9=rax xorl %eax,%eax @@ -167,7 +156,12 @@ ENTRY(ia32_sysenter_target) cmpq $(IA32_NR_syscalls-1),%rax ja ia32_badsys sysenter_do_call: - IA32_ARG_FIXUP + /* 32bit syscall -> 64bit C ABI argument conversion */ + movl %edi,%r8d /* arg5 */ + movl %ebp,%r9d /* arg6 */ + xchg %ecx,%esi /* rsi:arg2, rcx:arg4 */ + movl %ebx,%edi /* arg1 */ + movl %edx,%edx /* arg3 (zero extension) */ sysenter_dispatch: call *ia32_sys_call_table(,%rax,8) movq %rax,RAX(%rsp) @@ -343,7 +337,12 @@ ENTRY(ia32_cstar_target) cmpq $IA32_NR_syscalls-1,%rax ja ia32_badsys cstar_do_call: - IA32_ARG_FIXUP 1 + /* 32bit syscall -> 64bit C ABI argument conversion */ + movl %edi,%r8d /* arg5 */ + /* r9 already loaded */ /* arg6 */ + xchg %ecx,%esi /* rsi:arg2, rcx:arg4 */ + movl %ebx,%edi /* arg1 */ + movl %edx,%edx /* arg3 (zero extension) */ cstar_dispatch: call *ia32_sys_call_table(,%rax,8) movq %rax,RAX(%rsp) @@ -460,7 +459,12 @@ ENTRY(ia32_syscall) cmpq $(IA32_NR_syscalls-1),%rax ja ia32_badsys ia32_do_call: - IA32_ARG_FIXUP + /* 32bit syscall -> 64bit C ABI argument conversion */ + movl %edi,%r8d /* arg5 */ + movl %ebp,%r9d /* arg6 */ + xchg %ecx,%esi /* rsi:arg2, rcx:arg4 */ + movl %ebx,%edi /* arg1 */ + movl %edx,%edx /* arg3 (zero extension) */ call *ia32_sys_call_table(,%rax,8) # xxx: rip relative ia32_sysret: movq %rax,RAX(%rsp) -- 1.8.1.4