From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754685Ab2INNpu (ORCPT ); Fri, 14 Sep 2012 09:45:50 -0400 Received: from service87.mimecast.com ([91.220.42.44]:46224 "EHLO service87.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751692Ab2INNpr convert rfc822-to-8bit (ORCPT ); Fri, 14 Sep 2012 09:45:47 -0400 Message-ID: <50533500.2020606@arm.com> Date: Fri, 14 Sep 2012 14:45:36 +0100 From: Marc Zyngier User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:14.0) Gecko/20120714 Thunderbird/14.0 MIME-Version: 1.0 To: Stefano Stabellini CC: "arnd@arndb.de" , "xen-devel@lists.xensource.com" , "linaro-dev@lists.linaro.org" , "Ian.Campbell@citrix.com" , "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 References: <1347621207-11294-2-git-send-email-stefano.stabellini@eu.citrix.com> In-Reply-To: <1347621207-11294-2-git-send-email-stefano.stabellini@eu.citrix.com> X-Enigmail-Version: 1.5a1pre X-OriginalArrivalTime: 14 Sep 2012 13:45:38.0123 (UTC) FILETIME=[392AF1B0:01CD927F] X-MC-Unique: 112091414454404301 Content-Type: text/plain; charset=WINDOWS-1252 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. M. -- Jazz is not dead. It just smells funny...