gnu-efi/lib/x86_64/callwrap.c

/*
 * Convert SysV calling convention to EFI x86_64 calling convention
 *
 *  Copyright (C) 2007-2010 Intel Corp
 *	Bibo Mao <bibo.mao@intel.com>
 *	Chandramouli Narayanan<mouli@linux.intel.com>
 *	Huang Ying <ying.huang@intel.com>
 *
 *  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above
 *   copyright notice, this list of conditions and the following
 *   disclaimer in the documentation and/or other materials
 *   provided with the distribution.
 * - Neither the name of Hewlett-Packard Co. nor the names of its
 *   contributors may be used to endorse or promote products derived
 *   from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
 *  CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
 *  INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 *  DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
 *  BE LIABLE FOR ANYDIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
 *  OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 *  PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 *  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
 *  TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
 *  THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 *  SUCH DAMAGE.
 */

/* uefi_call_wrapper() is a macro in efibind.h */
Initial commit gnu-efi_3.0r 2013-01-31 01:25:25 +04:00			`/*`
			`* Convert SysV calling convention to EFI x86_64 calling convention`
			`*`
			`* Copyright (C) 2007-2010 Intel Corp`
			`* Bibo Mao <bibo.mao@intel.com>`
			`* Chandramouli Narayanan<mouli@linux.intel.com>`
			`* Huang Ying <ying.huang@intel.com>`
			`*`
			`* All rights reserved.`
			`*`
			`* Redistribution and use in source and binary forms, with or without`
			`* modification, are permitted provided that the following conditions`
			`* are met:`
			`*`
			`* - Redistributions of source code must retain the above copyright`
			`* notice, this list of conditions and the following disclaimer.`
			`* - Redistributions in binary form must reproduce the above`
			`* copyright notice, this list of conditions and the following`
			`* disclaimer in the documentation and/or other materials`
			`* provided with the distribution.`
			`* - Neither the name of Hewlett-Packard Co. nor the names of its`
			`* contributors may be used to endorse or promote products derived`
			`* from this software without specific prior written permission.`
			`*`
			`* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND`
			`* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,`
			`* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF`
			`* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE`
			`* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS`
			`* BE LIABLE FOR ANYDIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,`
			`* OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,`
			`* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR`
			`* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY`
			`* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR`
			`* TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF`
			`* THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF`
			`* SUCH DAMAGE.`
			`*/`

fix parameter-passing corruption on x86_64 for >= 5 args On x86_64 without HAVE_USE_MS_ABI support, uefi_call_wrapper() is a variadic function. Parameters >=5 are copied to the stack and, when passed small immediate values (and possibly other parameters), gcc would emit a movl instruction before calling uefi_call_wrapper(). As a result, only the lower 32b of these stack values are significant, the upper 32b potentially contain garbage. Considering that uefi_call_wrapper() assumes these arguments are clean 64b values before calling the efi_callX() trampolines, the latter may be passed garbage. This makes calling functions like EFI_PCI_IO_PROTOCOL.Mem.Read()/Write() or BS->OpenProtocol() quite unreliable. This patch fixes this by turning uefi_call_wrapper() into a macro that allows to expose the efi_callX() trampoline signatures to the callers, so that gcc can know upfront that it has to pass all arguments to efi_callX() as clean 64b values (eg. movq for immediates). The _cast64_efi_callX macros are just here to avoid a gcc warning, they do nothing otherwise. Signed-off-by: David Decotigny <decot@googlers.com> 2013-06-12 17:38:10 +04:00			`/* uefi_call_wrapper() is a macro in efibind.h */`