From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id CBB7BECE58E for ; Wed, 9 Oct 2019 13:08:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9CC6721848 for ; Wed, 9 Oct 2019 13:08:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="PWOuk/u9" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731378AbfJINIJ (ORCPT ); Wed, 9 Oct 2019 09:08:09 -0400 Received: from mail-wr1-f66.google.com ([209.85.221.66]:33075 "EHLO mail-wr1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731254AbfJINIJ (ORCPT ); Wed, 9 Oct 2019 09:08:09 -0400 Received: by mail-wr1-f66.google.com with SMTP id b9so2944975wrs.0 for ; Wed, 09 Oct 2019 06:08:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=SJluTP7Iu318juEgmVZU0u8unpaoIGl5t74+Cp5PAms=; b=PWOuk/u9tL4/wz/b4im/a8ZiEpZR7EmAStrfBM7wBr3/zK5gmcTd8VE7OGe3SdPWs/ Jn3/dWp14MCRSW4zVXOuWfcagR8lbmEmD1HAAmPSHPimtoiQ/awPhVmq4F7xpLwDS1DC tZxYu96zJekPT5Z6I+qRQKLxhuV8Tc4VWQrCkdFegHHi66IjKOQXhNhAxiboWo1hGpQ+ GeGkg1F6ZCGAS/Q/0xjtKI6KwAH0ogkYE8u13+UVClgQde09UMHStW+W02BeFjEoo8dF lwy9qTdUxceflZnU9zAx4QYdodwuNKWTe2F/aTEM0zgwVDtv3sTq5ndjeNo0xl19uMTZ kCPQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=SJluTP7Iu318juEgmVZU0u8unpaoIGl5t74+Cp5PAms=; b=rWim9ILJx3hscPL/E56moBIvYhd/G4qJdkZiQWLYLukZL/fkTBlUIpoRiuY1um1P7K RlnS3BwtbedDQGNBvtwc5A/CKtvZRwYcCvXq18vXymnDEMBNvjOEpCHs8MfIAEymythn Dwxd+UfIgeFN54K+0gP9KqDUzBU+3tFGHikVmWQwHde8a9tCN1MW0b/WnQQ0Ta4HJK3r zhnBa6Kl75jXNn/WE0TqqewnF/3HnoG5FpL7sWvYJHVaW8B6cYyrziaWzNT4/9nX2bph ZiMxpXh5ASwr0U730zICSvudQ98LkPMoADNK5+02tv7HGJlCtLMHoLnHAMsaEJ4gJDfb Xv+w== X-Gm-Message-State: APjAAAUQscC84Wsu37aEDDAVAm6q+Kmp+pIDumxHjhZ3z/5YHfO17ZBH eqdG41cMUTpf0WJVAGoj5x1s6ms+L1KhMgAt/OBSyg== X-Google-Smtp-Source: APXvYqzfeWVaOVDYT+4IReJSxU7fFbkWaSySdf/aALt3QzhNYwcH96IJX4rFio408cCNtT1Zp8EGzLXmQOFZrOjLTjI= X-Received: by 2002:adf:9f08:: with SMTP id l8mr2733709wrf.325.1570626485423; Wed, 09 Oct 2019 06:08:05 -0700 (PDT) MIME-Version: 1.0 References: <20191004145056.43267-1-hdegoede@redhat.com> <20191004145056.43267-2-hdegoede@redhat.com> In-Reply-To: <20191004145056.43267-2-hdegoede@redhat.com> From: Ard Biesheuvel Date: Wed, 9 Oct 2019 15:07:54 +0200 Message-ID: Subject: Re: [PATCH v7 1/8] efi: Export boot-services code and data as debugfs-blobs To: Hans de Goede Cc: Darren Hart , Andy Shevchenko , Luis Chamberlain , Greg Kroah-Hartman , "Rafael J . Wysocki" , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H . Peter Anvin" , Jonathan Corbet , Dmitry Torokhov , Peter Jones , Dave Olsthoorn , "the arch/x86 maintainers" , platform-driver-x86@vger.kernel.org, linux-efi , Linux Kernel Mailing List , Linux Doc Mailing List , linux-input@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 4 Oct 2019 at 16:51, Hans de Goede wrote: > > Sometimes it is useful to be able to dump the efi boot-services code and > data. This commit adds these as debugfs-blobs to /sys/kernel/debug/efi, > but only if efi=debug is passed on the kernel-commandline as this requires > not freeing those memory-regions, which costs 20+ MB of RAM. > > Reviewed-by: Greg Kroah-Hartman > Acked-by: Ard Biesheuvel > Signed-off-by: Hans de Goede > --- > Changes in v5: > -Rename the EFI_BOOT_SERVICES flag to EFI_PRESERVE_BS_REGIONS > > Changes in v4: > -Add new EFI_BOOT_SERVICES flag and use it to determine if the boot-services > memory segments are available (and thus if it makes sense to register the > debugfs bits for them) > > Changes in v2: > -Do not call pr_err on debugfs call failures > --- > arch/x86/platform/efi/efi.c | 1 + > arch/x86/platform/efi/quirks.c | 4 +++ > drivers/firmware/efi/efi.c | 53 ++++++++++++++++++++++++++++++++++ > include/linux/efi.h | 1 + > 4 files changed, 59 insertions(+) > > diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c > index c202e1b07e29..847730f7e74b 100644 > --- a/arch/x86/platform/efi/efi.c > +++ b/arch/x86/platform/efi/efi.c > @@ -232,6 +232,7 @@ int __init efi_memblock_x86_reserve_range(void) > efi.memmap.desc_version); > > memblock_reserve(pmap, efi.memmap.nr_map * efi.memmap.desc_size); > + set_bit(EFI_PRESERVE_BS_REGIONS, &efi.flags); Should we add a Kconfig symbol to opt into this behavior [set by the driver in question], instead of always preserving all boot services regions on all x86 systems? > > return 0; > } > diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c > index 3b9fd679cea9..fab12ebf0ada 100644 > --- a/arch/x86/platform/efi/quirks.c > +++ b/arch/x86/platform/efi/quirks.c > @@ -411,6 +411,10 @@ void __init efi_free_boot_services(void) > int num_entries = 0; > void *new, *new_md; > > + /* Keep all regions for /sys/kernel/debug/efi */ > + if (efi_enabled(EFI_DBG)) > + return; > + > for_each_efi_memory_desc(md) { > unsigned long long start = md->phys_addr; > unsigned long long size = md->num_pages << EFI_PAGE_SHIFT; > diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c > index 8d3e778e988b..abba49c4c46d 100644 > --- a/drivers/firmware/efi/efi.c > +++ b/drivers/firmware/efi/efi.c > @@ -17,6 +17,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -314,6 +315,55 @@ static __init int efivar_ssdt_load(void) > static inline int efivar_ssdt_load(void) { return 0; } > #endif > > +#ifdef CONFIG_DEBUG_FS > + > +#define EFI_DEBUGFS_MAX_BLOBS 32 > + > +static struct debugfs_blob_wrapper debugfs_blob[EFI_DEBUGFS_MAX_BLOBS]; > + > +static void __init efi_debugfs_init(void) > +{ > + struct dentry *efi_debugfs; > + efi_memory_desc_t *md; > + char name[32]; > + int type_count[EFI_BOOT_SERVICES_DATA + 1] = {}; > + int i = 0; > + > + efi_debugfs = debugfs_create_dir("efi", NULL); > + if (IS_ERR_OR_NULL(efi_debugfs)) > + return; > + > + for_each_efi_memory_desc(md) { > + switch (md->type) { > + case EFI_BOOT_SERVICES_CODE: > + snprintf(name, sizeof(name), "boot_services_code%d", > + type_count[md->type]++); > + break; > + case EFI_BOOT_SERVICES_DATA: > + snprintf(name, sizeof(name), "boot_services_data%d", > + type_count[md->type]++); > + break; > + default: > + continue; > + } > + > + debugfs_blob[i].size = md->num_pages << EFI_PAGE_SHIFT; > + debugfs_blob[i].data = memremap(md->phys_addr, > + debugfs_blob[i].size, > + MEMREMAP_WB); > + if (!debugfs_blob[i].data) > + continue; > + > + debugfs_create_blob(name, 0400, efi_debugfs, &debugfs_blob[i]); > + i++; > + if (i == EFI_DEBUGFS_MAX_BLOBS) > + break; > + } > +} > +#else > +static inline void efi_debugfs_init(void) {} > +#endif > + > /* > * We register the efi subsystem with the firmware subsystem and the > * efivars subsystem with the efi subsystem, if the system was booted with > @@ -370,6 +420,9 @@ static int __init efisubsys_init(void) > goto err_remove_group; > } > > + if (efi_enabled(EFI_DBG) && efi_enabled(EFI_PRESERVE_BS_REGIONS)) > + efi_debugfs_init(); > + > return 0; > > err_remove_group: > diff --git a/include/linux/efi.h b/include/linux/efi.h > index bd3837022307..2a30a1bd8bdf 100644 > --- a/include/linux/efi.h > +++ b/include/linux/efi.h > @@ -1202,6 +1202,7 @@ extern int __init efi_setup_pcdp_console(char *); > #define EFI_DBG 8 /* Print additional debug info at runtime */ > #define EFI_NX_PE_DATA 9 /* Can runtime data regions be mapped non-executable? */ > #define EFI_MEM_ATTR 10 /* Did firmware publish an EFI_MEMORY_ATTRIBUTES table? */ > +#define EFI_PRESERVE_BS_REGIONS 11 /* Are EFI boot-services memory segments available? */ > > #ifdef CONFIG_EFI > /* > -- > 2.23.0 >