diff options
| author | Hans de Goede <hdegoede@redhat.com> | 2020-01-15 17:35:45 +0100 |
|---|---|---|
| committer | Ard Biesheuvel <ardb@kernel.org> | 2020-03-03 10:27:30 +0100 |
| commit | 0e72a6a3cfc3a32273f5e99bfaa4407f4917d343 (patch) | |
| tree | 5d44b2405c3c655701b6a1a72d3100dc4b85d4dd /drivers | |
| parent | bb6d3fb354c5ee8d6bde2d576eb7220ea09862b9 (diff) | |
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@linuxfoundation.org>
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20200115163554.101315-2-hdegoede@redhat.com
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/firmware/efi/efi.c | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index 621220ab3d0e..201a6799671d 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -17,6 +17,7 @@ #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 +326,59 @@ free_entry: 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; + } + + if (i >= EFI_DEBUGFS_MAX_BLOBS) { + pr_warn("More then %d EFI boot service segments, only showing first %d in debugfs\n", + EFI_DEBUGFS_MAX_BLOBS, EFI_DEBUGFS_MAX_BLOBS); + break; + } + + 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++; + } +} +#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 @@ -381,6 +435,9 @@ 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: |