From d2f7cbe7b26a74dbbbf8f325b2a6fd01bc34032c Mon Sep 17 00:00:00 2001 From: Borislav Petkov Date: Thu, 31 Oct 2013 17:25:08 +0100 Subject: x86/efi: Runtime services virtual mapping We map the EFI regions needed for runtime services non-contiguously, with preserved alignment on virtual addresses starting from -4G down for a total max space of 64G. This way, we provide for stable runtime services addresses across kernels so that a kexec'd kernel can still use them. Thus, they're mapped in a separate pagetable so that we don't pollute the kernel namespace. Add an efi= kernel command line parameter for passing miscellaneous options and chicken bits from the command line. While at it, add a chicken bit called "efi=old_map" which can be used as a fallback to the old runtime services mapping method in case there's some b0rkage with a particular EFI implementation (haha, it is hard to hold up the sarcasm here...). Also, add the UEFI RT VA space to Documentation/x86/x86_64/mm.txt. Signed-off-by: Borislav Petkov Signed-off-by: Matt Fleming --- include/linux/efi.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include') diff --git a/include/linux/efi.h b/include/linux/efi.h index bc5687d0f315..6c0ca528300c 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -653,6 +653,7 @@ extern int __init efi_setup_pcdp_console(char *); #define EFI_RUNTIME_SERVICES 3 /* Can we use runtime services? */ #define EFI_MEMMAP 4 /* Can we use EFI memory map? */ #define EFI_64BIT 5 /* Is the firmware 64-bit? */ +#define EFI_ARCH_1 6 /* First arch-specific bit */ #ifdef CONFIG_EFI # ifdef CONFIG_X86 -- cgit v1.2.3 From a0998eb15afeffbf52a2c2829318f67df9ac57b8 Mon Sep 17 00:00:00 2001 From: Dave Young Date: Fri, 20 Dec 2013 18:02:17 +0800 Subject: efi: Export more EFI table variables to sysfs Export fw_vendor, runtime and config table physical addresses to /sys/firmware/efi/{fw_vendor,runtime,config_table} because kexec kernels need them. From EFI spec these 3 variables will be updated to virtual address after entering virtual mode. But kernel startup code will need the physical address. Signed-off-by: Dave Young Tested-by: Toshi Kani Signed-off-by: Matt Fleming --- Documentation/ABI/testing/sysfs-firmware-efi | 20 ++++++++++++++ arch/x86/platform/efi/efi.c | 4 +++ drivers/firmware/efi/efi.c | 41 +++++++++++++++++++++++++++- include/linux/efi.h | 3 ++ 4 files changed, 67 insertions(+), 1 deletion(-) create mode 100644 Documentation/ABI/testing/sysfs-firmware-efi (limited to 'include') diff --git a/Documentation/ABI/testing/sysfs-firmware-efi b/Documentation/ABI/testing/sysfs-firmware-efi new file mode 100644 index 000000000000..05874da7ce80 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-firmware-efi @@ -0,0 +1,20 @@ +What: /sys/firmware/efi/fw_vendor +Date: December 2013 +Contact: Dave Young +Description: It shows the physical address of firmware vendor field in the + EFI system table. +Users: Kexec + +What: /sys/firmware/efi/runtime +Date: December 2013 +Contact: Dave Young +Description: It shows the physical address of runtime service table entry in + the EFI system table. +Users: Kexec + +What: /sys/firmware/efi/config_table +Date: December 2013 +Contact: Dave Young +Description: It shows the physical address of config table entry in the EFI + system table. +Users: Kexec diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index 4694632ef581..28591072fbb7 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -653,6 +653,10 @@ void __init efi_init(void) set_bit(EFI_SYSTEM_TABLES, &x86_efi_facility); + efi.config_table = (unsigned long)efi.systab->tables; + efi.fw_vendor = (unsigned long)efi.systab->fw_vendor; + efi.runtime = (unsigned long)efi.systab->runtime; + /* * Show what we know for posterity */ diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index 2e2fbdec0845..72533af72b98 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -32,6 +32,9 @@ struct efi __read_mostly efi = { .hcdp = EFI_INVALID_TABLE_ADDR, .uga = EFI_INVALID_TABLE_ADDR, .uv_systab = EFI_INVALID_TABLE_ADDR, + .fw_vendor = EFI_INVALID_TABLE_ADDR, + .runtime = EFI_INVALID_TABLE_ADDR, + .config_table = EFI_INVALID_TABLE_ADDR, }; EXPORT_SYMBOL(efi); @@ -71,13 +74,49 @@ static ssize_t systab_show(struct kobject *kobj, static struct kobj_attribute efi_attr_systab = __ATTR(systab, 0400, systab_show, NULL); +#define EFI_FIELD(var) efi.var + +#define EFI_ATTR_SHOW(name) \ +static ssize_t name##_show(struct kobject *kobj, \ + struct kobj_attribute *attr, char *buf) \ +{ \ + return sprintf(buf, "0x%lx\n", EFI_FIELD(name)); \ +} + +EFI_ATTR_SHOW(fw_vendor); +EFI_ATTR_SHOW(runtime); +EFI_ATTR_SHOW(config_table); + +static struct kobj_attribute efi_attr_fw_vendor = __ATTR_RO(fw_vendor); +static struct kobj_attribute efi_attr_runtime = __ATTR_RO(runtime); +static struct kobj_attribute efi_attr_config_table = __ATTR_RO(config_table); + static struct attribute *efi_subsys_attrs[] = { &efi_attr_systab.attr, - NULL, /* maybe more in the future? */ + &efi_attr_fw_vendor.attr, + &efi_attr_runtime.attr, + &efi_attr_config_table.attr, + NULL, }; +static umode_t efi_attr_is_visible(struct kobject *kobj, + struct attribute *attr, int n) +{ + umode_t mode = attr->mode; + + if (attr == &efi_attr_fw_vendor.attr) + return (efi.fw_vendor == EFI_INVALID_TABLE_ADDR) ? 0 : mode; + else if (attr == &efi_attr_runtime.attr) + return (efi.runtime == EFI_INVALID_TABLE_ADDR) ? 0 : mode; + else if (attr == &efi_attr_config_table.attr) + return (efi.config_table == EFI_INVALID_TABLE_ADDR) ? 0 : mode; + + return mode; +} + static struct attribute_group efi_subsys_attr_group = { .attrs = efi_subsys_attrs, + .is_visible = efi_attr_is_visible, }; static struct efivars generic_efivars; diff --git a/include/linux/efi.h b/include/linux/efi.h index 6c0ca528300c..fb60b10b7bd9 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -556,6 +556,9 @@ extern struct efi { unsigned long hcdp; /* HCDP table */ unsigned long uga; /* UGA table */ unsigned long uv_systab; /* UV system table */ + unsigned long fw_vendor; /* fw_vendor */ + unsigned long runtime; /* runtime table */ + unsigned long config_table; /* config tables */ efi_get_time_t *get_time; efi_set_time_t *set_time; efi_get_wakeup_time_t *get_wakeup_time; -- cgit v1.2.3 From 926172d46038d7610b6b8d84e40db727cefb482d Mon Sep 17 00:00:00 2001 From: Dave Young Date: Fri, 20 Dec 2013 18:02:18 +0800 Subject: efi: Export EFI runtime memory mapping to sysfs kexec kernel will need exactly same mapping for EFI runtime memory ranges. Thus here export the runtime ranges mapping to sysfs, kexec-tools will assemble them and pass to 2nd kernel via setup_data. Introducing a new directory /sys/firmware/efi/runtime-map just like /sys/firmware/memmap. Containing below attribute in each file of that directory: attribute num_pages phys_addr type virt_addr Signed-off-by: Dave Young Tested-by: Toshi Kani Signed-off-by: Matt Fleming --- .../ABI/testing/sysfs-firmware-efi-runtime-map | 34 ++++ arch/x86/platform/efi/efi.c | 46 +++++- drivers/firmware/efi/Kconfig | 11 ++ drivers/firmware/efi/Makefile | 1 + drivers/firmware/efi/efi.c | 4 + drivers/firmware/efi/runtime-map.c | 181 +++++++++++++++++++++ include/linux/efi.h | 13 ++ 7 files changed, 287 insertions(+), 3 deletions(-) create mode 100644 Documentation/ABI/testing/sysfs-firmware-efi-runtime-map create mode 100644 drivers/firmware/efi/runtime-map.c (limited to 'include') diff --git a/Documentation/ABI/testing/sysfs-firmware-efi-runtime-map b/Documentation/ABI/testing/sysfs-firmware-efi-runtime-map new file mode 100644 index 000000000000..c61b9b348e99 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-firmware-efi-runtime-map @@ -0,0 +1,34 @@ +What: /sys/firmware/efi/runtime-map/ +Date: December 2013 +Contact: Dave Young +Description: Switching efi runtime services to virtual mode requires + that all efi memory ranges which have the runtime attribute + bit set to be mapped to virtual addresses. + + The efi runtime services can only be switched to virtual + mode once without rebooting. The kexec kernel must maintain + the same physical to virtual address mappings as the first + kernel. The mappings are exported to sysfs so userspace tools + can reassemble them and pass them into the kexec kernel. + + /sys/firmware/efi/runtime-map/ is the directory the kernel + exports that information in. + + subdirectories are named with the number of the memory range: + + /sys/firmware/efi/runtime-map/0 + /sys/firmware/efi/runtime-map/1 + /sys/firmware/efi/runtime-map/2 + /sys/firmware/efi/runtime-map/3 + ... + + Each subdirectory contains five files: + + attribute : The attributes of the memory range. + num_pages : The size of the memory range in pages. + phys_addr : The physical address of the memory range. + type : The type of the memory range. + virt_addr : The virtual address of the memory range. + + Above values are all hexadecimal numbers with the '0x' prefix. +Users: Kexec diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index 28591072fbb7..74fe7a719508 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -76,6 +76,9 @@ static __initdata efi_config_table_type_t arch_tables[] = { {NULL_GUID, NULL, NULL}, }; +static void *efi_runtime_map; +static int nr_efi_runtime_map; + /* * Returns 1 if 'facility' is enabled, 0 otherwise. */ @@ -824,6 +827,39 @@ static void __init get_systab_virt_addr(efi_memory_desc_t *md) } } +static int __init save_runtime_map(void) +{ + efi_memory_desc_t *md; + void *tmp, *p, *q = NULL; + int count = 0; + + for (p = memmap.map; p < memmap.map_end; p += memmap.desc_size) { + md = p; + + if (!(md->attribute & EFI_MEMORY_RUNTIME) || + (md->type == EFI_BOOT_SERVICES_CODE) || + (md->type == EFI_BOOT_SERVICES_DATA)) + continue; + tmp = krealloc(q, (count + 1) * memmap.desc_size, GFP_KERNEL); + if (!tmp) + goto out; + q = tmp; + + memcpy(q + count * memmap.desc_size, md, memmap.desc_size); + count++; + } + + efi_runtime_map = q; + nr_efi_runtime_map = count; + efi_runtime_map_setup(efi_runtime_map, nr_efi_runtime_map, + boot_params.efi_info.efi_memdesc_size); + + return 0; +out: + kfree(q); + return -ENOMEM; +} + /* * Map efi memory ranges for runtime serivce and update new_memmap with virtual * addresses. @@ -849,7 +885,7 @@ static void * __init efi_map_regions(int *count) tmp = krealloc(new_memmap, (*count + 1) * memmap.desc_size, GFP_KERNEL); if (!tmp) - goto out_krealloc; + goto out; new_memmap = tmp; memcpy(new_memmap + (*count * memmap.desc_size), md, memmap.desc_size); @@ -857,7 +893,7 @@ static void * __init efi_map_regions(int *count) } return new_memmap; -out_krealloc: +out: kfree(new_memmap); return NULL; } @@ -883,7 +919,7 @@ void __init efi_enter_virtual_mode(void) { efi_status_t status; void *new_memmap = NULL; - int count = 0; + int err, count = 0; efi.systab = NULL; @@ -904,6 +940,10 @@ void __init efi_enter_virtual_mode(void) return; } + err = save_runtime_map(); + if (err) + pr_err("Error saving runtime map, efi runtime on kexec non-functional!!\n"); + BUG_ON(!efi.systab); efi_setup_page_tables(); diff --git a/drivers/firmware/efi/Kconfig b/drivers/firmware/efi/Kconfig index 3150aa4874e8..730f5f2e8b7f 100644 --- a/drivers/firmware/efi/Kconfig +++ b/drivers/firmware/efi/Kconfig @@ -39,4 +39,15 @@ config EFI_VARS_PSTORE_DEFAULT_DISABLE config UEFI_CPER def_bool n +config EFI_RUNTIME_MAP + bool "Export efi runtime maps to sysfs" + depends on X86 && EFI && KEXEC + default y + help + Export efi runtime memory maps to /sys/firmware/efi/runtime-map. + That memory map is used for example by kexec to set up efi virtual + mapping the 2nd kernel, but can also be used for debugging purposes. + + See also Documentation/ABI/testing/sysfs-firmware-efi-runtime-map. + endmenu diff --git a/drivers/firmware/efi/Makefile b/drivers/firmware/efi/Makefile index 9ba156d3c775..a58e0f183a08 100644 --- a/drivers/firmware/efi/Makefile +++ b/drivers/firmware/efi/Makefile @@ -5,3 +5,4 @@ obj-y += efi.o vars.o obj-$(CONFIG_EFI_VARS) += efivars.o obj-$(CONFIG_EFI_VARS_PSTORE) += efi-pstore.o obj-$(CONFIG_UEFI_CPER) += cper.o +obj-$(CONFIG_EFI_RUNTIME_MAP) += runtime-map.o diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index 72533af72b98..4753bac65279 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -167,6 +167,10 @@ static int __init efisubsys_init(void) goto err_unregister; } + error = efi_runtime_map_init(efi_kobj); + if (error) + goto err_remove_group; + /* and the standard mountpoint for efivarfs */ efivars_kobj = kobject_create_and_add("efivars", efi_kobj); if (!efivars_kobj) { diff --git a/drivers/firmware/efi/runtime-map.c b/drivers/firmware/efi/runtime-map.c new file mode 100644 index 000000000000..97cdd16a2169 --- /dev/null +++ b/drivers/firmware/efi/runtime-map.c @@ -0,0 +1,181 @@ +/* + * linux/drivers/efi/runtime-map.c + * Copyright (C) 2013 Red Hat, Inc., Dave Young + * + * This file is released under the GPLv2. + */ + +#include +#include +#include +#include +#include +#include + +#include + +static void *efi_runtime_map; +static int nr_efi_runtime_map; +static u32 efi_memdesc_size; + +struct efi_runtime_map_entry { + efi_memory_desc_t md; + struct kobject kobj; /* kobject for each entry */ +}; + +static struct efi_runtime_map_entry **map_entries; + +struct map_attribute { + struct attribute attr; + ssize_t (*show)(struct efi_runtime_map_entry *entry, char *buf); +}; + +static inline struct map_attribute *to_map_attr(struct attribute *attr) +{ + return container_of(attr, struct map_attribute, attr); +} + +static ssize_t type_show(struct efi_runtime_map_entry *entry, char *buf) +{ + return snprintf(buf, PAGE_SIZE, "0x%x\n", entry->md.type); +} + +#define EFI_RUNTIME_FIELD(var) entry->md.var + +#define EFI_RUNTIME_U64_ATTR_SHOW(name) \ +static ssize_t name##_show(struct efi_runtime_map_entry *entry, char *buf) \ +{ \ + return snprintf(buf, PAGE_SIZE, "0x%llx\n", EFI_RUNTIME_FIELD(name)); \ +} + +EFI_RUNTIME_U64_ATTR_SHOW(phys_addr); +EFI_RUNTIME_U64_ATTR_SHOW(virt_addr); +EFI_RUNTIME_U64_ATTR_SHOW(num_pages); +EFI_RUNTIME_U64_ATTR_SHOW(attribute); + +static inline struct efi_runtime_map_entry *to_map_entry(struct kobject *kobj) +{ + return container_of(kobj, struct efi_runtime_map_entry, kobj); +} + +static ssize_t map_attr_show(struct kobject *kobj, struct attribute *attr, + char *buf) +{ + struct efi_runtime_map_entry *entry = to_map_entry(kobj); + struct map_attribute *map_attr = to_map_attr(attr); + + return map_attr->show(entry, buf); +} + +static struct map_attribute map_type_attr = __ATTR_RO(type); +static struct map_attribute map_phys_addr_attr = __ATTR_RO(phys_addr); +static struct map_attribute map_virt_addr_attr = __ATTR_RO(virt_addr); +static struct map_attribute map_num_pages_attr = __ATTR_RO(num_pages); +static struct map_attribute map_attribute_attr = __ATTR_RO(attribute); + +/* + * These are default attributes that are added for every memmap entry. + */ +static struct attribute *def_attrs[] = { + &map_type_attr.attr, + &map_phys_addr_attr.attr, + &map_virt_addr_attr.attr, + &map_num_pages_attr.attr, + &map_attribute_attr.attr, + NULL +}; + +static const struct sysfs_ops map_attr_ops = { + .show = map_attr_show, +}; + +static void map_release(struct kobject *kobj) +{ + struct efi_runtime_map_entry *entry; + + entry = to_map_entry(kobj); + kfree(entry); +} + +static struct kobj_type __refdata map_ktype = { + .sysfs_ops = &map_attr_ops, + .default_attrs = def_attrs, + .release = map_release, +}; + +static struct kset *map_kset; + +static struct efi_runtime_map_entry * +add_sysfs_runtime_map_entry(struct kobject *kobj, int nr) +{ + int ret; + struct efi_runtime_map_entry *entry; + + if (!map_kset) { + map_kset = kset_create_and_add("runtime-map", NULL, kobj); + if (!map_kset) + return ERR_PTR(-ENOMEM); + } + + entry = kzalloc(sizeof(*entry), GFP_KERNEL); + if (!entry) { + kset_unregister(map_kset); + return entry; + } + + memcpy(&entry->md, efi_runtime_map + nr * efi_memdesc_size, + sizeof(efi_memory_desc_t)); + + kobject_init(&entry->kobj, &map_ktype); + entry->kobj.kset = map_kset; + ret = kobject_add(&entry->kobj, NULL, "%d", nr); + if (ret) { + kobject_put(&entry->kobj); + kset_unregister(map_kset); + return ERR_PTR(ret); + } + + return entry; +} + +void efi_runtime_map_setup(void *map, int nr_entries, u32 desc_size) +{ + efi_runtime_map = map; + nr_efi_runtime_map = nr_entries; + efi_memdesc_size = desc_size; +} + +int __init efi_runtime_map_init(struct kobject *efi_kobj) +{ + int i, j, ret = 0; + struct efi_runtime_map_entry *entry; + + if (!efi_runtime_map) + return 0; + + map_entries = kzalloc(nr_efi_runtime_map * sizeof(entry), GFP_KERNEL); + if (!map_entries) { + ret = -ENOMEM; + goto out; + } + + for (i = 0; i < nr_efi_runtime_map; i++) { + entry = add_sysfs_runtime_map_entry(efi_kobj, i); + if (IS_ERR(entry)) { + ret = PTR_ERR(entry); + goto out_add_entry; + } + *(map_entries + i) = entry; + } + + return 0; +out_add_entry: + for (j = i - 1; j > 0; j--) { + entry = *(map_entries + j); + kobject_put(&entry->kobj); + } + if (map_kset) + kset_unregister(map_kset); +out: + return ret; +} diff --git a/include/linux/efi.h b/include/linux/efi.h index fb60b10b7bd9..e64540746c63 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -872,4 +872,17 @@ int efivars_sysfs_init(void); #endif /* CONFIG_EFI_VARS */ +#ifdef CONFIG_EFI_RUNTIME_MAP +int efi_runtime_map_init(struct kobject *); +void efi_runtime_map_setup(void *, int, u32); +#else +static inline int efi_runtime_map_init(struct kobject *kobj) +{ + return 0; +} + +static inline void +efi_runtime_map_setup(void *map, int nr_entries, u32 desc_size) {} +#endif + #endif /* _LINUX_EFI_H */ -- cgit v1.2.3