Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933761AbbGGU16 (ORCPT ); Tue, 7 Jul 2015 16:27:58 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:19639 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933610AbbGGU02 (ORCPT ); Tue, 7 Jul 2015 16:26:28 -0400 Date: Tue, 7 Jul 2015 16:26:15 -0400 From: Konrad Rzeszutek Wilk To: Boris Ostrovsky Cc: david.vrabel@citrix.com, roger.pau@citrix.com, elena.ufimtseva@oracle.com, stefano.stabellini@eu.citrix.com, tim@xen.org, jbeulich@suse.com, andrew.cooper3@citrix.com, ian.campbell@citrix.com, wei.liu2@citrix.com, ian.jackson@eu.citrix.com, xen-devel@lists.xenproject.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/6] xen/x86/pvh: Save %rbx in xen_pvh_early_cpu_init() Message-ID: <20150707202615.GH6372@l.oracle.com> References: <1436240065-10813-1-git-send-email-boris.ostrovsky@oracle.com> <1436240065-10813-2-git-send-email-boris.ostrovsky@oracle.com> <20150707201626.GG6372@l.oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150707201626.GG6372@l.oracle.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-Source-IP: aserv0021.oracle.com [141.146.126.233] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3805 Lines: 112 > > diff --git a/arch/x86/xen/xen-head.S b/arch/x86/xen/xen-head.S > > index 8afdfcc..b1508a8 100644 > > --- a/arch/x86/xen/xen-head.S > > +++ b/arch/x86/xen/xen-head.S > > @@ -56,28 +56,28 @@ ENTRY(startup_xen) > > * @entry: true if this is a secondary vcpu coming up on this entry > > * point, false if this is the boot CPU being initialized for > > * the first time (%rsi) > > - * > > - * Note: This is called as a function on the boot CPU, and is the entry point > > - * on the secondary CPU. > > */ > > ENTRY(xen_pvh_early_cpu_init) > > - mov %rsi, %r11 > > + mov %rbx, -8(%rsp) > > > > +/* Entry point for secondary CPUs */ Actually, could you do this (since the BSP can access the stack and it can do jumps) - not compile tested: This way you don't even need the second argument - as there are two functions now - and no need to figure out whether one is for BSP and the other for other CPUs. diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index 7953e68..c8e0655 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -1462,7 +1462,7 @@ static void __init xen_pvh_early_guest_init(void) xen_have_vector_callback = 1; - xen_pvh_early_cpu_init(0, false); + xen_pvh_early_cpu_init(0); xen_pvh_set_cr_flags(0); #ifdef CONFIG_X86_32 diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c index ca7ee1f..e53be3b 100644 --- a/arch/x86/xen/smp.c +++ b/arch/x86/xen/smp.c @@ -426,7 +426,6 @@ cpu_initialize_context(unsigned int cpu, struct task_struct *idle) ctxt->user_regs.eip = (unsigned long)xen_pvh_early_cpu_init_secondary; ctxt->user_regs.rdi = cpu; - ctxt->user_regs.rsi = true; /* entry == true */ } #endif ctxt->user_regs.esp = idle->thread.sp0 - sizeof(struct pt_regs); diff --git a/arch/x86/xen/smp.h b/arch/x86/xen/smp.h index bf2b43c..bec860a 100644 --- a/arch/x86/xen/smp.h +++ b/arch/x86/xen/smp.h @@ -9,10 +9,10 @@ extern void xen_send_IPI_all(int vector); extern void xen_send_IPI_self(int vector); #ifdef CONFIG_XEN_PVH -extern void xen_pvh_early_cpu_init(int cpu, bool entry); +extern void xen_pvh_early_cpu_init(int cpu); extern void xen_pvh_early_cpu_init_secondary(int cpu, bool entry); #else -static inline void xen_pvh_early_cpu_init(int cpu, bool entry) +static inline void xen_pvh_early_cpu_init(int cpu) { } static inline void xen_pvh_early_cpu_init_secondary(int cpu, bool entry) diff --git a/arch/x86/xen/xen-head.S b/arch/x86/xen/xen-head.S index b1508a8..1c20669 100644 --- a/arch/x86/xen/xen-head.S +++ b/arch/x86/xen/xen-head.S @@ -53,15 +53,17 @@ ENTRY(startup_xen) /* * xen_pvh_early_cpu_init() - early PVH VCPU initialization * @cpu: this cpu number (%rdi) - * @entry: true if this is a secondary vcpu coming up on this entry - * point, false if this is the boot CPU being initialized for - * the first time (%rsi) */ ENTRY(xen_pvh_early_cpu_init) mov %rbx, -8(%rsp) - -/* Entry point for secondary CPUs */ + xor %esi, %esi + jmp 1f +/* Entry point for secondary CPUs. Can't touch stack (no jumps!) until NX + * is dealt with. + */ ENTRY(xen_pvh_early_cpu_init_secondary) + mov $1, %esi +1: /* Gather features to see if NX implemented. */ mov $0x80000001, %eax cpuid @@ -72,9 +74,9 @@ ENTRY(xen_pvh_early_cpu_init_secondary) bts $_EFER_SCE, %eax bt $20, %ebx - jnc 1f /* No NX, skip setting it */ + jnc 2f /* No NX, skip setting it */ bts $_EFER_NX, %eax -1: wrmsr +2: wrmsr mov -8(%rsp), %rbx #ifdef CONFIG_SMP cmp $0, %esi -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/