From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754703AbbBZWm7 (ORCPT ); Thu, 26 Feb 2015 17:42:59 -0500 Received: from mail-pa0-f51.google.com ([209.85.220.51]:35039 "EHLO mail-pa0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754648AbbBZWlV (ORCPT ); Thu, 26 Feb 2015 17:41:21 -0500 From: Andy Lutomirski To: x86@kernel.org, linux-kernel@vger.kernel.org Cc: Borislav Petkov , Oleg Nesterov , Denys Vlasenko , Linus Torvalds , "H. Peter Anvin" , Andy Lutomirski , Frederic Weisbecker , Alexei Starovoitov , Will Drewry , Kees Cook Subject: [PATCH 10/16] x86: entry_64.S: move save_paranoid and ret_from_fork closer to their users Date: Thu, 26 Feb 2015 14:40:33 -0800 Message-Id: <6446bbfe4094532623a5b83779b7015fec167a9d.1424989793.git.luto@amacapital.net> X-Mailer: git-send-email 2.1.0 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Denys Vlasenko For some odd reason, these two functions are at the very top of the file. save_paranoid's caller is approximately in the middle of it, move it there. Move ret_from_fork to be right after fork/exec helpers. This is a pure block move, nothing is changed in the function bodies. Signed-off-by: Denys Vlasenko CC: Linus Torvalds CC: Oleg Nesterov CC: Borislav Petkov 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 Message-Id: <1424736744-13414-2-git-send-email-dvlasenk@redhat.com> Signed-off-by: Andy Lutomirski --- arch/x86/kernel/entry_64.S | 106 ++++++++++++++++++++++----------------------- 1 file changed, 53 insertions(+), 53 deletions(-) diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S index 73c314a6e436..cd1d62b3200a 100644 --- a/arch/x86/kernel/entry_64.S +++ b/arch/x86/kernel/entry_64.S @@ -202,59 +202,6 @@ ENDPROC(native_usergs_sysret64) CFI_REL_OFFSET r15, R15+\offset .endm -ENTRY(save_paranoid) - XCPT_FRAME 1 RDI+8 - cld - SAVE_C_REGS 8 - SAVE_EXTRA_REGS 8 - movl $1,%ebx - movl $MSR_GS_BASE,%ecx - rdmsr - testl %edx,%edx - js 1f /* negative -> in kernel */ - SWAPGS - xorl %ebx,%ebx -1: ret - CFI_ENDPROC -END(save_paranoid) - -/* - * A newly forked process directly context switches into this address. - * - * rdi: prev task we switched from - */ -ENTRY(ret_from_fork) - DEFAULT_FRAME - - LOCK ; btr $TIF_FORK,TI_flags(%r8) - - pushq_cfi $0x0002 - popfq_cfi # reset kernel eflags - - call schedule_tail # rdi: 'prev' task parameter - - GET_THREAD_INFO(%rcx) - - RESTORE_EXTRA_REGS - - testl $3,CS(%rsp) # from kernel_thread? - jz 1f - - testl $_TIF_IA32, TI_flags(%rcx) # 32-bit compat task needs IRET - jnz int_ret_from_sys_call - - RESTORE_TOP_OF_STACK %rdi - jmp ret_from_sys_call # go to the SYSRET fastpath - -1: - movq %rbp, %rdi - call *%rbx - movl $0, RAX(%rsp) - RESTORE_EXTRA_REGS - jmp int_ret_from_sys_call - CFI_ENDPROC -END(ret_from_fork) - /* * 64bit SYSCALL instruction entry. Up to 6 arguments in registers. * @@ -582,6 +529,43 @@ END(stub_x32_execveat) #endif /* + * A newly forked process directly context switches into this address. + * + * rdi: prev task we switched from + */ +ENTRY(ret_from_fork) + DEFAULT_FRAME + + LOCK ; btr $TIF_FORK,TI_flags(%r8) + + pushq_cfi $0x0002 + popfq_cfi # reset kernel eflags + + call schedule_tail # rdi: 'prev' task parameter + + GET_THREAD_INFO(%rcx) + + RESTORE_EXTRA_REGS + + testl $3,CS(%rsp) # from kernel_thread? + jz 1f + + testl $_TIF_IA32, TI_flags(%rcx) # 32-bit compat task needs IRET + jnz int_ret_from_sys_call + + RESTORE_TOP_OF_STACK %rdi + jmp ret_from_sys_call # go to the SYSRET fastpath + +1: + movq %rbp, %rdi + call *%rbx + movl $0, RAX(%rsp) + RESTORE_EXTRA_REGS + jmp int_ret_from_sys_call + CFI_ENDPROC +END(ret_from_fork) + +/* * Build the entry stubs and pointer table with some assembler magic. * We pack 7 stubs into a single 32-byte chunk, which will fit in a * single cache line on all modern x86 implementations. @@ -1270,6 +1254,22 @@ idtentry async_page_fault do_async_page_fault has_error_code=1 idtentry machine_check has_error_code=0 paranoid=1 do_sym=*machine_check_vector(%rip) #endif +ENTRY(save_paranoid) + XCPT_FRAME 1 RDI+8 + cld + SAVE_C_REGS 8 + SAVE_EXTRA_REGS 8 + movl $1,%ebx + movl $MSR_GS_BASE,%ecx + rdmsr + testl %edx,%edx + js 1f /* negative -> in kernel */ + SWAPGS + xorl %ebx,%ebx +1: ret + CFI_ENDPROC +END(save_paranoid) + /* * "Paranoid" exit path from exception stack. This is invoked * only on return from non-NMI IST interrupts that came -- 2.1.0