Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759320Ab3HMWWm (ORCPT ); Tue, 13 Aug 2013 18:22:42 -0400 Received: from mail-ob0-f178.google.com ([209.85.214.178]:35461 "EHLO mail-ob0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759164Ab3HMWWl (ORCPT ); Tue, 13 Aug 2013 18:22:41 -0400 MIME-Version: 1.0 In-Reply-To: <1376430401-67445-1-git-send-email-linn@hp.com> References: <1376348482-1357-1-git-send-email-linn@hp.com> <1376430401-67445-1-git-send-email-linn@hp.com> Date: Tue, 13 Aug 2013 15:22:40 -0700 X-Google-Sender-Auth: 4wbXRT-PabFqBnbwUYp7fguDwjs Message-ID: Subject: Re: [PATCH v3] x86: avoid remapping data in parse_setup_data() From: Yinghai Lu To: Linn Crosetto Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , "the arch/x86 maintainers" , Paul McKenney , David Howells , Michael Kerrisk-manpages , Pekka Enberg , Jacob Shin , Linux Kernel Mailing List Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4493 Lines: 110 On Tue, Aug 13, 2013 at 2:46 PM, Linn Crosetto wrote: > Type SETUP_PCI, added by setup_efi_pci(), may advertise a ROM size > larger than early_memremap() is able to handle, which is currently > limited to 256kB. If this occurs it leads to a NULL dereference in > parse_setup_data(). > > To avoid this, remap the setup_data header and allow parsing functions > for individual types to handle their own data remapping. > > Signed-off-by: Linn Crosetto > --- > v3: Remove data remapping code from parse_setup_data() and add it to > parse_e820_ext(). Acked-by: Yinghai Lu > > arch/x86/include/asm/e820.h | 2 +- > arch/x86/kernel/e820.c | 5 ++++- > arch/x86/kernel/setup.c | 19 ++++++++----------- > 3 files changed, 13 insertions(+), 13 deletions(-) > > diff --git a/arch/x86/include/asm/e820.h b/arch/x86/include/asm/e820.h > index cccd07f..779c2ef 100644 > --- a/arch/x86/include/asm/e820.h > +++ b/arch/x86/include/asm/e820.h > @@ -29,7 +29,7 @@ extern void e820_setup_gap(void); > extern int e820_search_gap(unsigned long *gapstart, unsigned long *gapsize, > unsigned long start_addr, unsigned long long end_addr); > struct setup_data; > -extern void parse_e820_ext(struct setup_data *data); > +extern void parse_e820_ext(u64 phys_addr, u32 data_len); > > #if defined(CONFIG_X86_64) || \ > (defined(CONFIG_X86_32) && defined(CONFIG_HIBERNATION)) > diff --git a/arch/x86/kernel/e820.c b/arch/x86/kernel/e820.c > index d32abea..174da5f 100644 > --- a/arch/x86/kernel/e820.c > +++ b/arch/x86/kernel/e820.c > @@ -658,15 +658,18 @@ __init void e820_setup_gap(void) > * boot_params.e820_map, others are passed via SETUP_E820_EXT node of > * linked list of struct setup_data, which is parsed here. > */ > -void __init parse_e820_ext(struct setup_data *sdata) > +void __init parse_e820_ext(u64 phys_addr, u32 data_len) > { > int entries; > struct e820entry *extmap; > + struct setup_data *sdata; > > + sdata = early_memremap(phys_addr, data_len); > entries = sdata->len / sizeof(struct e820entry); > extmap = (struct e820entry *)(sdata->data); > __append_e820_map(extmap, entries); > sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map); > + early_iounmap(sdata, data_len); > printk(KERN_INFO "e820: extended physical RAM map:\n"); > e820_print_map("extended"); > } > diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c > index f8ec578..234e1e3 100644 > --- a/arch/x86/kernel/setup.c > +++ b/arch/x86/kernel/setup.c > @@ -426,25 +426,23 @@ static void __init reserve_initrd(void) > static void __init parse_setup_data(void) > { > struct setup_data *data; > - u64 pa_data; > + u64 pa_data, pa_next; > > pa_data = boot_params.hdr.setup_data; > while (pa_data) { > - u32 data_len, map_len; > + u32 data_len, map_len, data_type; > > map_len = max(PAGE_SIZE - (pa_data & ~PAGE_MASK), > (u64)sizeof(struct setup_data)); > data = early_memremap(pa_data, map_len); > data_len = data->len + sizeof(struct setup_data); > - if (data_len > map_len) { > - early_iounmap(data, map_len); > - data = early_memremap(pa_data, data_len); > - map_len = data_len; > - } > + data_type = data->type; > + pa_next = data->next; > + early_iounmap(data, map_len); > > - switch (data->type) { > + switch (data_type) { > case SETUP_E820_EXT: > - parse_e820_ext(data); > + parse_e820_ext(pa_data, data_len); > break; > case SETUP_DTB: > add_dtb(pa_data); > @@ -452,8 +450,7 @@ static void __init parse_setup_data(void) > default: > break; > } > - pa_data = data->next; > - early_iounmap(data, map_len); > + pa_data = pa_next; > } > } -- 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/