Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753468AbcD1UpP (ORCPT ); Thu, 28 Apr 2016 16:45:15 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36987 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752906AbcD1UpL (ORCPT ); Thu, 28 Apr 2016 16:45:11 -0400 From: Josh Poimboeuf To: Jessica Yu , Jiri Kosina , Miroslav Benes , Ingo Molnar , Peter Zijlstra , Michael Ellerman , Heiko Carstens Cc: live-patching@vger.kernel.org, linux-kernel@vger.kernel.org, x86@kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, Vojtech Pavlik , Jiri Slaby , Petr Mladek , Chris J Arges , Andy Lutomirski Subject: [RFC PATCH v2 02/18] x86/asm/head: use a common function for starting CPUs Date: Thu, 28 Apr 2016 15:44:33 -0500 Message-Id: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1934 Lines: 62 There are two different pieces of code for starting a CPU: start_cpu0() and the end of secondary_startup_64(). They're identical except for the stack setup. Combine the common parts into a shared start_cpu() function. Signed-off-by: Josh Poimboeuf --- arch/x86/kernel/head_64.S | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index 792c3bb..6dbd2c0 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -264,13 +264,15 @@ ENTRY(secondary_startup_64) movl $MSR_GS_BASE,%ecx movl initial_gs(%rip),%eax movl initial_gs+4(%rip),%edx - wrmsr + wrmsr /* rsi is pointer to real mode structure with interesting info. pass it to C */ movq %rsi, %rdi - - /* Finally jump to run C code and to be on real kernel address + +ENTRY(start_cpu) + /* + * Jump to run C code and to be on a real kernel address. * Since we are running on identity-mapped space we have to jump * to the full 64bit address, this is only possible as indirect * jump. In addition we need to ensure %cs is set so we make this @@ -299,6 +301,7 @@ ENTRY(secondary_startup_64) pushq $__KERNEL_CS # set correct cs pushq %rax # target address in negative space lretq +ENDPROC(start_cpu) #include "verify_cpu.S" @@ -306,15 +309,11 @@ ENTRY(secondary_startup_64) /* * Boot CPU0 entry point. It's called from play_dead(). Everything has been set * up already except stack. We just set up stack here. Then call - * start_secondary(). + * start_secondary() via start_cpu(). */ ENTRY(start_cpu0) - movq initial_stack(%rip),%rsp - movq initial_code(%rip),%rax - pushq $0 # fake return address to stop unwinder - pushq $__KERNEL_CS # set correct cs - pushq %rax # target address in negative space - lretq + movq initial_stack(%rip), %rsp + jmp start_cpu ENDPROC(start_cpu0) #endif -- 2.4.11