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Message-Id: <20180429093558.5411-2-hdegoede@redhat.com> Date: Sun, 29 Apr 2018 11:35:54 +0200 From: Hans de Goede <hdegoede@...hat.com> To: Ard Biesheuvel <ard.biesheuvel@...aro.org>, "Luis R . Rodriguez" <mcgrof@...nel.org>, Greg Kroah-Hartman <gregkh@...uxfoundation.org>, Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...hat.com>, "H . Peter Anvin" <hpa@...or.com> Cc: Hans de Goede <hdegoede@...hat.com>, Peter Jones <pjones@...hat.com>, Dave Olsthoorn <dave@...aar.me>, Will Deacon <will.deacon@....com>, Andy Lutomirski <luto@...nel.org>, Matt Fleming <matt@...eblueprint.co.uk>, David Howells <dhowells@...hat.com>, Mimi Zohar <zohar@...ux.vnet.ibm.com>, Josh Triplett <josh@...htriplett.org>, dmitry.torokhov@...il.com, mfuzzey@...keon.com, Kalle Valo <kvalo@...eaurora.org>, Arend Van Spriel <arend.vanspriel@...adcom.com>, Linus Torvalds <torvalds@...ux-foundation.org>, nbroeking@...com, bjorn.andersson@...aro.org, Torsten Duwe <duwe@...e.de>, Kees Cook <keescook@...omium.org>, x86@...nel.org, linux-efi@...r.kernel.org, linux-kernel@...r.kernel.org Subject: [PATCH v5 1/5] efi: Export boot-services code and data as debugfs-blobs 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 <gregkh@...uxfoundation.org> Acked-by: Ard Biesheuvel <ard.biesheuvel@...aro.org> Signed-off-by: Hans de Goede <hdegoede@...hat.com> --- 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 9061babfbc83..82bbbbf0836d 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -208,6 +208,7 @@ 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); return 0; } diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c index 36c1f8b9f7e0..16bdb9e3b343 100644 --- a/arch/x86/platform/efi/quirks.c +++ b/arch/x86/platform/efi/quirks.c @@ -376,6 +376,10 @@ 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 232f4915223b..1590e4d6a857 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -18,6 +18,7 @@ #include <linux/kobject.h> #include <linux/module.h> #include <linux/init.h> +#include <linux/debugfs.h> #include <linux/device.h> #include <linux/efi.h> #include <linux/of.h> @@ -325,6 +326,55 @@ 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 @@ -369,6 +419,9 @@ 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 f1b7d68ac460..791088360c1e 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -1144,6 +1144,7 @@ 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 /* -- 2.17.0
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