From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756154Ab2INODX (ORCPT ); Fri, 14 Sep 2012 10:03:23 -0400 Received: from smtp.eu.citrix.com ([62.200.22.115]:4264 "EHLO SMTP.EU.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752289Ab2INODU (ORCPT ); Fri, 14 Sep 2012 10:03:20 -0400 X-IronPort-AV: E=Sophos;i="4.80,423,1344211200"; d="scan'208";a="14548302" Date: Fri, 14 Sep 2012 15:02:35 +0100 From: Stefano Stabellini X-X-Sender: sstabellini@kaball.uk.xensource.com To: Marc Zyngier CC: Stefano Stabellini , "arnd@arndb.de" , "xen-devel@lists.xensource.com" , "linaro-dev@lists.linaro.org" , Ian Campbell , "konrad.wilk@oracle.com" , Catalin Marinas , "Tim (Xen.org)" , "linux-kernel@vger.kernel.org" , "linux@arm.linux.org.uk" , "linux-arm-kernel@lists.infradead.org" , Dave Martin Subject: Re: [PATCH v4 02/24] xen/arm: hypercalls In-Reply-To: <50533500.2020606@arm.com> Message-ID: References: <1347621207-11294-2-git-send-email-stefano.stabellini@eu.citrix.com> <50533500.2020606@arm.com> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 14 Sep 2012, Marc Zyngier wrote: > On 14/09/12 12:13, Stefano Stabellini wrote: > > Use r12 to pass the hypercall number to the hypervisor. > > > > We need a register to pass the hypercall number because we might not > > know it at compile time and HVC only takes an immediate argument. > > > > Among the available registers r12 seems to be the best choice because it > > is defined as "intra-procedure call scratch register". > > > > Use the ISS to pass an hypervisor specific tag. > > > > > > Changes in v2: > > - define an HYPERCALL macro for 5 arguments hypercall wrappers, even if > > at the moment is unused; > > - use ldm instead of pop; > > - fix up comments. > > > > > > Signed-off-by: Stefano Stabellini > > --- > > arch/arm/include/asm/xen/hypercall.h | 50 ++++++++++++++++ > > arch/arm/xen/Makefile | 2 +- > > arch/arm/xen/hypercall.S | 106 ++++++++++++++++++++++++++++++++++ > > 3 files changed, 157 insertions(+), 1 deletions(-) > > create mode 100644 arch/arm/include/asm/xen/hypercall.h > > create mode 100644 arch/arm/xen/hypercall.S > > > > diff --git a/arch/arm/include/asm/xen/hypercall.h b/arch/arm/include/asm/xen/hypercall.h > > new file mode 100644 > > index 0000000..4ac0624 > > --- /dev/null > > +++ b/arch/arm/include/asm/xen/hypercall.h > > @@ -0,0 +1,50 @@ > > +/****************************************************************************** > > + * hypercall.h > > + * > > + * Linux-specific hypervisor handling. > > + * > > + * Stefano Stabellini , Citrix, 2012 > > + * > > + * This program is free software; you can redistribute it and/or > > + * modify it under the terms of the GNU General Public License version 2 > > + * as published by the Free Software Foundation; or, when distributed > > + * separately from the Linux kernel or incorporated into other > > + * software packages, subject to the following license: > > + * > > + * Permission is hereby granted, free of charge, to any person obtaining a copy > > + * of this source file (the "Software"), to deal in the Software without > > + * restriction, including without limitation the rights to use, copy, modify, > > + * merge, publish, distribute, sublicense, and/or sell copies of the Software, > > + * and to permit persons to whom the Software is furnished to do so, subject to > > + * the following conditions: > > + * > > + * The above copyright notice and this permission notice shall be included in > > + * all copies or substantial portions of the Software. > > + * > > + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR > > + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, > > + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE > > + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER > > + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING > > + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS > > + * IN THE SOFTWARE. > > + */ > > + > > +#ifndef _ASM_ARM_XEN_HYPERCALL_H > > +#define _ASM_ARM_XEN_HYPERCALL_H > > + > > +#include > > + > > +long privcmd_call(unsigned call, unsigned long a1, > > + unsigned long a2, unsigned long a3, > > + unsigned long a4, unsigned long a5); > > +int HYPERVISOR_xen_version(int cmd, void *arg); > > +int HYPERVISOR_console_io(int cmd, int count, char *str); > > +int HYPERVISOR_grant_table_op(unsigned int cmd, void *uop, unsigned int count); > > +int HYPERVISOR_sched_op(int cmd, void *arg); > > +int HYPERVISOR_event_channel_op(int cmd, void *arg); > > +unsigned long HYPERVISOR_hvm_op(int op, void *arg); > > +int HYPERVISOR_memory_op(unsigned int cmd, void *arg); > > +int HYPERVISOR_physdev_op(int cmd, void *arg); > > + > > +#endif /* _ASM_ARM_XEN_HYPERCALL_H */ > > diff --git a/arch/arm/xen/Makefile b/arch/arm/xen/Makefile > > index 0bad594..b9d6acc 100644 > > --- a/arch/arm/xen/Makefile > > +++ b/arch/arm/xen/Makefile > > @@ -1 +1 @@ > > -obj-y := enlighten.o > > +obj-y := enlighten.o hypercall.o > > diff --git a/arch/arm/xen/hypercall.S b/arch/arm/xen/hypercall.S > > new file mode 100644 > > index 0000000..074f5ed > > --- /dev/null > > +++ b/arch/arm/xen/hypercall.S > > @@ -0,0 +1,106 @@ > > +/****************************************************************************** > > + * hypercall.S > > + * > > + * Xen hypercall wrappers > > + * > > + * Stefano Stabellini , Citrix, 2012 > > + * > > + * This program is free software; you can redistribute it and/or > > + * modify it under the terms of the GNU General Public License version 2 > > + * as published by the Free Software Foundation; or, when distributed > > + * separately from the Linux kernel or incorporated into other > > + * software packages, subject to the following license: > > + * > > + * Permission is hereby granted, free of charge, to any person obtaining a copy > > + * of this source file (the "Software"), to deal in the Software without > > + * restriction, including without limitation the rights to use, copy, modify, > > + * merge, publish, distribute, sublicense, and/or sell copies of the Software, > > + * and to permit persons to whom the Software is furnished to do so, subject to > > + * the following conditions: > > + * > > + * The above copyright notice and this permission notice shall be included in > > + * all copies or substantial portions of the Software. > > + * > > + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR > > + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, > > + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE > > + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER > > + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING > > + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS > > + * IN THE SOFTWARE. > > + */ > > + > > +/* > > + * The Xen hypercall calling convention is very similar to the ARM > > + * procedure calling convention: the first paramter is passed in r0, the > > + * second in r1, the third in r2 and the fourth in r3. Considering that > > + * Xen hypercalls have 5 arguments at most, the fifth paramter is passed > > + * in r4, differently from the procedure calling convention of using the > > + * stack for that case. > > + * > > + * The hypercall number is passed in r12. > > + * > > + * The return value is in r0. > > + * > > + * The hvc ISS is required to be 0xEA1, that is the Xen specific ARM > > + * hypercall tag. > > + */ > > + > > +#include > > +#include > > +#include > > + > > + > > +/* HVC 0xEA1 */ > > +#ifdef CONFIG_THUMB2_KERNEL > > +#define xen_hvc .word 0xf7e08ea1 > > +#else > > +#define xen_hvc .word 0xe140ea71 > > +#endif > > You should consider using Dave Martin's opcode injection series for > that. The patches are already in Russell's for-next branch. I am all for using Dave's patches and I have even already sent a patch to change the wrappers to use __HVC: http://marc.info/?l=linux-kernel&m=134513261623427&w=2 I have only temporarely dropped it, only to reduce the amount of external dependencies of this series. It already depends on Konrad's stable/for-linus-3.7, so I would rather send this patch out later on its own...