From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934428AbZJIX0s (ORCPT ); Fri, 9 Oct 2009 19:26:48 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761386AbZJIX0r (ORCPT ); Fri, 9 Oct 2009 19:26:47 -0400 Received: from kroah.org ([198.145.64.141]:56298 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761478AbZJIX0p (ORCPT ); Fri, 9 Oct 2009 19:26:45 -0400 X-Mailbox-Line: From gregkh@mini.kroah.org Fri Oct 9 16:22:33 2009 Message-Id: <20091009232233.689031894@mini.kroah.org> User-Agent: quilt/0.48-1 Date: Fri, 09 Oct 2009 16:21:25 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Jan Beulich , Ingo Molnar , Chuck Ebbert Subject: [2/8] x86-64: slightly stream-line 32-bit syscall entry code From: gregkh@mini.kroah.org References: <20091009232123.464253035@mini.kroah.org> Content-Disposition: inline; filename=x86-64-slightly-stream-line-32-bit-syscall-entry-code.patch In-Reply-To: <20091009232300.GA403@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jan Beulich commit 295286a89107c353b9677bc604361c537fd6a1c0 upstream x86-64: slightly stream-line 32-bit syscall entry code [ required for following patch to apply properly ] Avoid updating registers or memory twice as well as needlessly loading or copying registers. Signed-off-by: Jan Beulich Signed-off-by: Ingo Molnar Cc: Chuck Ebbert Signed-off-by: Greg Kroah-Hartman --- arch/x86/ia32/ia32entry.S | 26 ++++++++++---------------- 1 file changed, 10 insertions(+), 16 deletions(-) --- a/arch/x86/ia32/ia32entry.S +++ b/arch/x86/ia32/ia32entry.S @@ -39,11 +39,11 @@ .endm /* clobbers %eax */ - .macro CLEAR_RREGS + .macro CLEAR_RREGS _r9=rax xorl %eax,%eax movq %rax,R11(%rsp) movq %rax,R10(%rsp) - movq %rax,R9(%rsp) + movq %\_r9,R9(%rsp) movq %rax,R8(%rsp) .endm @@ -52,11 +52,10 @@ * We don't reload %eax because syscall_trace_enter() returned * the value it wants us to use in the table lookup. */ - .macro LOAD_ARGS32 offset - movl \offset(%rsp),%r11d - movl \offset+8(%rsp),%r10d + .macro LOAD_ARGS32 offset, _r9=0 + .if \_r9 movl \offset+16(%rsp),%r9d - movl \offset+24(%rsp),%r8d + .endif movl \offset+40(%rsp),%ecx movl \offset+48(%rsp),%edx movl \offset+56(%rsp),%esi @@ -145,7 +144,7 @@ ENTRY(ia32_sysenter_target) SAVE_ARGS 0,0,1 /* no need to do an access_ok check here because rbp has been 32bit zero extended */ -1: movl (%rbp),%r9d +1: movl (%rbp),%ebp .section __ex_table,"a" .quad 1b,ia32_badarg .previous @@ -157,7 +156,7 @@ ENTRY(ia32_sysenter_target) cmpl $(IA32_NR_syscalls-1),%eax ja ia32_badsys sysenter_do_call: - IA32_ARG_FIXUP 1 + IA32_ARG_FIXUP sysenter_dispatch: call *ia32_sys_call_table(,%rax,8) movq %rax,RAX-ARGOFFSET(%rsp) @@ -234,20 +233,17 @@ sysexit_audit: #endif sysenter_tracesys: - xchgl %r9d,%ebp #ifdef CONFIG_AUDITSYSCALL testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags(%r10) jz sysenter_auditsys #endif SAVE_REST CLEAR_RREGS - movq %r9,R9(%rsp) movq $-ENOSYS,RAX(%rsp)/* ptrace can change this for a bad syscall */ movq %rsp,%rdi /* &pt_regs -> arg1 */ call syscall_trace_enter LOAD_ARGS32 ARGOFFSET /* reload args from stack in case ptrace changed it */ RESTORE_REST - xchgl %ebp,%r9d cmpl $(IA32_NR_syscalls-1),%eax ja int_ret_from_sys_call /* sysenter_tracesys has set RAX(%rsp) */ jmp sysenter_do_call @@ -314,9 +310,9 @@ ENTRY(ia32_cstar_target) testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%r10) CFI_REMEMBER_STATE jnz cstar_tracesys -cstar_do_call: cmpl $IA32_NR_syscalls-1,%eax ja ia32_badsys +cstar_do_call: IA32_ARG_FIXUP 1 cstar_dispatch: call *ia32_sys_call_table(,%rax,8) @@ -357,15 +353,13 @@ cstar_tracesys: #endif xchgl %r9d,%ebp SAVE_REST - CLEAR_RREGS - movq %r9,R9(%rsp) + CLEAR_RREGS r9 movq $-ENOSYS,RAX(%rsp) /* ptrace can change this for a bad syscall */ movq %rsp,%rdi /* &pt_regs -> arg1 */ call syscall_trace_enter - LOAD_ARGS32 ARGOFFSET /* reload args from stack in case ptrace changed it */ + LOAD_ARGS32 ARGOFFSET, 1 /* reload args from stack in case ptrace changed it */ RESTORE_REST xchgl %ebp,%r9d - movl RSP-ARGOFFSET(%rsp), %r8d cmpl $(IA32_NR_syscalls-1),%eax ja int_ret_from_sys_call /* cstar_tracesys has set RAX(%rsp) */ jmp cstar_do_call