From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752776Ab1IQLoa (ORCPT ); Sat, 17 Sep 2011 07:44:30 -0400 Received: from arkanian.console-pimps.org ([212.110.184.194]:38937 "EHLO arkanian.console-pimps.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751799Ab1IQLo3 (ORCPT ); Sat, 17 Sep 2011 07:44:29 -0400 Subject: Re: [PATCH v2 10/10] x86, efi: EFI boot stub support From: Matt Fleming To: Maarten Lankhorst Cc: Matt Domsch , "linux-kernel@vger.kernel.org" , "H. Peter Anvin" , Matthew Garrett , "x86@kernel.org" , Ingo Molnar , Thomas Gleixner , Mike Waychison , Andi Kleen , "Hargrave, Jordan" In-Reply-To: <4E71F33C.2010809@gmail.com> References: <1315838094-2307-1-git-send-email-matt@console-pimps.org> <1315838094-2307-11-git-send-email-matt@console-pimps.org> <4E6F69A1.9030406@gmail.com> <1316016478.3466.74.camel@mfleming-mobl1.ger.corp.intel.com> <20110915045231.GA32136@emperor.us.dell.com> <4E71B196.1060504@gmail.com> <20110915115255.GA4669@emperor.us.dell.com> <4E71F33C.2010809@gmail.com> Content-Type: text/plain; charset="UTF-8" Date: Sat, 17 Sep 2011 12:44:26 +0100 Message-ID: <1316259866.3578.20.camel@mfleming-mobl1.ger.corp.intel.com> Mime-Version: 1.0 X-Mailer: Evolution 2.32.2 (2.32.2-1.fc14) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2011-09-15 at 14:44 +0200, Maarten Lankhorst wrote: > Thanks, that makes much more sense. The man page makes mention > of extra arguments, but it kind of looked like the way to pass it was by > using -u -@ - which didn't work of course. :) > > So for reference: > efibootmgr -L 'EFI Native Linux Boot' -l '\vmlinuz.efi' -d /dev/sdb -u root=/dev/sdb2 console=ttyS0,115200n8 > > or as ASCII (reads much prettier in efibootmgr -v) > efibootmgr -L 'EFI Native Linux Boot' -l '\vmlinuz.efi' -d /dev/sdb root=/dev/sdb2 console=ttyS0,115200n8 > > This is the fixed patch I'm using for booting native linux kernel, > with passing args tested for UCS-2 and ASCII. It seems that > options_size can be halved safely, otherwise too much data is > copied from input. Thanks for looking at this Maarten. I've been staring at this code for far too long to notice buglets like this ;-) > I keep the first word, since otherwise the first argument is stripped off, > and it's probably harmless for the kernel to read something like > \vmlinuz.efi when you don't do a direct boot. > > Signed-off-by: Maarten Lankhorst > > diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c > index 6c34828..f77f9f5 100644 > --- a/arch/x86/boot/compressed/eboot.c > +++ b/arch/x86/boot/compressed/eboot.c > @@ -619,12 +619,12 @@ static efi_status_t make_boot_params(struct boot_params *boot_params, > unsigned long cmdline; > u8 nr_entries; > u16 *s2; > - u8 *s1; > + u8 *s1, *s2_8; > int i; > > hdr->type_of_loader = 0x21; > > - status = low_alloc(options_size, 1, &cmdline); > + status = low_alloc(options_size+1, 1, &cmdline); > if (status != EFI_SUCCESS) > goto fail; If no options were passed to the stub then we really don't want to do the allocation at all. Speaking of 'options_size', have you tested the values that get passed in from image->load_options? Running with the OVMF firmware under qemu I get sizes that are always larger than the NUL-byte in the argument string. For example, executing "bzImage foo" results in image->load_options being 38! Remember that ->options_size represents 16-bit characters and cmdline is going to be ASCII. options_size will always be larger than the value we need, so there's no need for the +1. At the moment we're actually allocating too much memory and that needs to be fixed. > @@ -633,27 +633,29 @@ static efi_status_t make_boot_params(struct boot_params *boot_params, > /* Convert unicode cmdline to ascii */ > s1 = (u8 *)(unsigned long)hdr->cmd_line_ptr; > s2 = (u16 *)options; > + s2_8 = (u8*)options; > > - if (s2 && options_size) { > - /* Skip first word, that's the kernel name */ > - while (*s2 && *s2 != ' ' && *s2 != '\n') { > - options_size--; > - s2++; > - } > - > - /* skip space */ > - if (*s2 == ' ') { > - options_size--; > - s2++; > - } > - > - while (options_size-- != 0) { > + if (options_size < 2 || !s2) { > + *s1 = '\0'; > + } else if (s2_8[1] && s2_8[1] < 0x80 && s2_8[0] < 0x80) { > + /* Passed as ASCII */ > + s2 = NULL; > + memcpy(s1, s2_8, options_size); > + hdr->cmdline_size = options_size; > + } else { > + options_size /= 2; /* Passed as UCS-2 */ > + while (options_size-- != 0 && *s2) { > *s1++ = *s2++; > hdr->cmdline_size++; > } > - > *s1 = '\0'; > + s1 = (u8 *)(unsigned long)hdr->cmd_line_ptr; > } > + if (hdr->cmdline_size && s1[hdr->cmdline_size - 1] == '\0') > + hdr->cmdline_size--; > + if (hdr->cmdline_size && s1[hdr->cmdline_size - 1] == '\n') > + hdr->cmdline_size--; > + s1[hdr->cmdline_size] = '\0'; > > hdr->ramdisk_image = 0; > hdr->ramdisk_size = 0; Hmm... I'm really not convinced that we need to support ASCII cmdline arguments, sorry. efibootmgr has support for UCS-2, so that's what should be used. Thanks for the review! -- Matt Fleming, Intel Open Source Technology Center