From 5a17dae422d7de4b776a9753cd4673a343a25b4b Mon Sep 17 00:00:00 2001 From: Matt Fleming Date: Tue, 5 Aug 2014 11:52:11 +0100 Subject: efi: Add efi= parameter parsing to the EFI boot stub We need a way to customize the behaviour of the EFI boot stub, in particular, we need a way to disable the "chunking" workaround, used when reading files from the EFI System Partition. One of my machines doesn't cope well when reading files in 1MB chunks to a buffer above the 4GB mark - it appears that the "chunking" bug workaround triggers another firmware bug. This was only discovered with commit 4bf7111f5016 ("x86/efi: Support initrd loaded above 4G"), and that commit is perfectly valid. The symptom I observed was a corrupt initrd rather than any kind of crash. efi= is now used to specify EFI parameters in two very different execution environments, the EFI boot stub and during kernel boot. There is also a slight performance optimization by enabling efi=nochunk, but that's offset by the fact that you're more likely to run into firmware issues, at least on x86. This is the rationale behind leaving the workaround enabled by default. Also provide some documentation for EFI_READ_CHUNK_SIZE and why we're using the current value of 1MB. Tested-by: Ard Biesheuvel Cc: Roy Franz Cc: Maarten Lankhorst Cc: Leif Lindholm Cc: Borislav Petkov Signed-off-by: Matt Fleming --- include/linux/efi.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include') diff --git a/include/linux/efi.h b/include/linux/efi.h index 45cb4ffdea62..518779fb5e90 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -1227,4 +1227,6 @@ efi_status_t handle_cmdline_files(efi_system_table_t *sys_table_arg, unsigned long *load_addr, unsigned long *load_size); +efi_status_t efi_parse_options(char *cmdline); + #endif /* _LINUX_EFI_H */ -- cgit v1.2.3 From b2e0a54a1296a91b800f316df7bef7d1905e4fd0 Mon Sep 17 00:00:00 2001 From: Dave Young Date: Thu, 14 Aug 2014 17:15:26 +0800 Subject: efi: Move noefi early param code out of x86 arch code noefi param can be used for arches other than X86 later, thus move it out of x86 platform code. Signed-off-by: Dave Young Signed-off-by: Matt Fleming --- Documentation/kernel-parameters.txt | 2 +- arch/x86/platform/efi/efi.c | 10 +--------- drivers/firmware/efi/efi.c | 13 +++++++++++++ include/linux/efi.h | 1 + 4 files changed, 16 insertions(+), 10 deletions(-) (limited to 'include') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 67d79597d9d6..08df275eee2b 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -2169,7 +2169,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted. nodsp [SH] Disable hardware DSP at boot time. - noefi [X86] Disable EFI runtime services support. + noefi Disable EFI runtime services support. noexec [IA-64] diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index a1f745b0bf1d..c90d3cd2728c 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -70,14 +70,6 @@ static efi_config_table_type_t arch_tables[] __initdata = { u64 efi_setup; /* efi setup_data physical address */ -static bool disable_runtime __initdata = false; -static int __init setup_noefi(char *arg) -{ - disable_runtime = true; - return 0; -} -early_param("noefi", setup_noefi); - int add_efi_memmap; EXPORT_SYMBOL(add_efi_memmap); @@ -492,7 +484,7 @@ void __init efi_init(void) if (!efi_runtime_supported()) pr_info("No EFI runtime due to 32/64-bit mismatch with kernel\n"); else { - if (disable_runtime || efi_runtime_init()) + if (efi_runtime_disabled() || efi_runtime_init()) return; } if (efi_memmap_init()) diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index 64ecbb501c50..c8f01a73edb5 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -41,6 +41,19 @@ struct efi __read_mostly efi = { }; EXPORT_SYMBOL(efi); +static bool disable_runtime; +static int __init setup_noefi(char *arg) +{ + disable_runtime = true; + return 0; +} +early_param("noefi", setup_noefi); + +bool efi_runtime_disabled(void) +{ + return disable_runtime; +} + static struct kobject *efi_kobj; static struct kobject *efivars_kobj; diff --git a/include/linux/efi.h b/include/linux/efi.h index 518779fb5e90..4812ed0b0374 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -1229,4 +1229,5 @@ efi_status_t handle_cmdline_files(efi_system_table_t *sys_table_arg, efi_status_t efi_parse_options(char *cmdline); +bool efi_runtime_disabled(void); #endif /* _LINUX_EFI_H */ -- cgit v1.2.3 From 6ccc72b87b83ece31c2a75bbe07f440b0378f7a9 Mon Sep 17 00:00:00 2001 From: Dave Young Date: Thu, 14 Aug 2014 17:15:27 +0800 Subject: lib: Add a generic cmdline parse function parse_option_str There should be a generic function to parse params like a=b,c Adding parse_option_str in lib/cmdline.c which will return true if there's specified option set in the params. Also updated efi=old_map parsing code to use the new function Signed-off-by: Dave Young Signed-off-by: Matt Fleming --- arch/x86/platform/efi/efi.c | 22 ++-------------------- include/linux/kernel.h | 1 + lib/cmdline.c | 29 +++++++++++++++++++++++++++++ 3 files changed, 32 insertions(+), 20 deletions(-) (limited to 'include') diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c index c90d3cd2728c..c73a7df5d37f 100644 --- a/arch/x86/platform/efi/efi.c +++ b/arch/x86/platform/efi/efi.c @@ -932,26 +932,8 @@ u64 efi_mem_attributes(unsigned long phys_addr) static int __init parse_efi_cmdline(char *str) { - if (*str == '=') - str++; - - while (*str) { - if (!strncmp(str, "old_map", 7)) { - set_bit(EFI_OLD_MEMMAP, &efi.flags); - str += strlen("old_map"); - } - - /* - * Skip any options we don't understand. Presumably - * they apply to the EFI boot stub. - */ - while (*str && *str != ',') - str++; - - /* If we hit a delimiter, skip it */ - if (*str == ',') - str++; - } + if (parse_option_str(str, "old_map")) + set_bit(EFI_OLD_MEMMAP, &efi.flags); return 0; } diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 95624bed87ef..f66427ef0628 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -407,6 +407,7 @@ int vsscanf(const char *, const char *, va_list); extern int get_option(char **str, int *pint); extern char *get_options(const char *str, int nints, int *ints); extern unsigned long long memparse(const char *ptr, char **retptr); +extern bool parse_option_str(const char *str, const char *option); extern int core_kernel_text(unsigned long addr); extern int core_kernel_data(unsigned long addr); diff --git a/lib/cmdline.c b/lib/cmdline.c index 76a712e6e20e..8f13cf73c2ec 100644 --- a/lib/cmdline.c +++ b/lib/cmdline.c @@ -160,3 +160,32 @@ unsigned long long memparse(const char *ptr, char **retptr) return ret; } EXPORT_SYMBOL(memparse); + +/** + * parse_option_str - Parse a string and check an option is set or not + * @str: String to be parsed + * @option: option name + * + * This function parses a string containing a comma-separated list of + * strings like a=b,c. + * + * Return true if there's such option in the string, or return false. + */ +bool parse_option_str(const char *str, const char *option) +{ + while (*str) { + if (!strncmp(str, option, strlen(option))) { + str += strlen(option); + if (!*str || *str == ',') + return true; + } + + while (*str && *str != ',') + str++; + + if (*str == ',') + str++; + } + + return false; +} -- cgit v1.2.3 From 9c97e0bdd4b4ae44577a1b1ec949e782084e9a78 Mon Sep 17 00:00:00 2001 From: Laszlo Ersek Date: Wed, 3 Sep 2014 13:32:19 +0200 Subject: efi: Add macro for EFI_MEMORY_UCE memory attribute Add the following macro from the UEFI spec, for completeness: EFI_MEMORY_UCE Memory cacheability attribute: The memory region supports being configured as not cacheable, exported, and supports the "fetch and add" semaphore mechanism. Signed-off-by: Laszlo Ersek Tested-by: Ard Biesheuvel Acked-by: Ard Biesheuvel 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 4812ed0b0374..7464032ae00a 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -92,6 +92,7 @@ typedef struct { #define EFI_MEMORY_WC ((u64)0x0000000000000002ULL) /* write-coalescing */ #define EFI_MEMORY_WT ((u64)0x0000000000000004ULL) /* write-through */ #define EFI_MEMORY_WB ((u64)0x0000000000000008ULL) /* write-back */ +#define EFI_MEMORY_UCE ((u64)0x0000000000000010ULL) /* uncached, exported */ #define EFI_MEMORY_WP ((u64)0x0000000000001000ULL) /* write-protect */ #define EFI_MEMORY_RP ((u64)0x0000000000002000ULL) /* read-protect */ #define EFI_MEMORY_XP ((u64)0x0000000000004000ULL) /* execute-protect */ -- cgit v1.2.3 From 98d2a6ca14520904a47c46258d3bad02ffcd3f96 Mon Sep 17 00:00:00 2001 From: Laszlo Ersek Date: Wed, 3 Sep 2014 13:32:20 +0200 Subject: efi: Introduce efi_md_typeattr_format() At the moment, there are three architectures debug-printing the EFI memory map at initialization: x86, ia64, and arm64. They all use different format strings, plus the EFI memory type and the EFI memory attributes are similarly hard to decode for a human reader. Introduce a helper __init function that formats the memory type and the memory attributes in a unified way, to a user-provided character buffer. The array "memory_type_name" is copied from the arm64 code, temporarily duplicating it. The (otherwise optional) braces around each string literal in the initializer list are dropped in order to match the kernel coding style more closely. The element size is tightened from 32 to 20 bytes (maximum actual string length + 1) so that we can derive the field width from the element size. Signed-off-by: Laszlo Ersek Tested-by: Ard Biesheuvel Acked-by: Ard Biesheuvel [ Dropped useless 'register' keyword, which compiler will ignore ] Signed-off-by: Matt Fleming --- drivers/firmware/efi/efi.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++ include/linux/efi.h | 7 ++++++ 2 files changed, 64 insertions(+) (limited to 'include') diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c index cebfa36a27ae..8590099ac148 100644 --- a/drivers/firmware/efi/efi.c +++ b/drivers/firmware/efi/efi.c @@ -445,3 +445,60 @@ int __init efi_get_fdt_params(struct efi_fdt_params *params, int verbose) return ret; } #endif /* CONFIG_EFI_PARAMS_FROM_FDT */ + +static __initdata char memory_type_name[][20] = { + "Reserved", + "Loader Code", + "Loader Data", + "Boot Code", + "Boot Data", + "Runtime Code", + "Runtime Data", + "Conventional Memory", + "Unusable Memory", + "ACPI Reclaim Memory", + "ACPI Memory NVS", + "Memory Mapped I/O", + "MMIO Port Space", + "PAL Code" +}; + +char * __init efi_md_typeattr_format(char *buf, size_t size, + const efi_memory_desc_t *md) +{ + char *pos; + int type_len; + u64 attr; + + pos = buf; + if (md->type >= ARRAY_SIZE(memory_type_name)) + type_len = snprintf(pos, size, "[type=%u", md->type); + else + type_len = snprintf(pos, size, "[%-*s", + (int)(sizeof(memory_type_name[0]) - 1), + memory_type_name[md->type]); + if (type_len >= size) + return buf; + + pos += type_len; + size -= type_len; + + attr = md->attribute; + if (attr & ~(EFI_MEMORY_UC | EFI_MEMORY_WC | EFI_MEMORY_WT | + EFI_MEMORY_WB | EFI_MEMORY_UCE | EFI_MEMORY_WP | + EFI_MEMORY_RP | EFI_MEMORY_XP | EFI_MEMORY_RUNTIME)) + snprintf(pos, size, "|attr=0x%016llx]", + (unsigned long long)attr); + else + snprintf(pos, size, "|%3s|%2s|%2s|%2s|%3s|%2s|%2s|%2s|%2s]", + attr & EFI_MEMORY_RUNTIME ? "RUN" : "", + attr & EFI_MEMORY_XP ? "XP" : "", + attr & EFI_MEMORY_RP ? "RP" : "", + attr & EFI_MEMORY_WP ? "WP" : "", + attr & EFI_MEMORY_UCE ? "UCE" : "", + attr & EFI_MEMORY_WB ? "WB" : "", + attr & EFI_MEMORY_WT ? "WT" : "", + attr & EFI_MEMORY_WC ? "WC" : "", + attr & EFI_MEMORY_UC ? "UC" : ""); + return buf; +} diff --git a/include/linux/efi.h b/include/linux/efi.h index 7464032ae00a..78b29b133e14 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -887,6 +887,13 @@ extern bool efi_poweroff_required(void); (md) <= (efi_memory_desc_t *)((m)->map_end - (m)->desc_size); \ (md) = (void *)(md) + (m)->desc_size) +/* + * Format an EFI memory descriptor's type and attributes to a user-provided + * character buffer, as per snprintf(), and return the buffer. + */ +char * __init efi_md_typeattr_format(char *buf, size_t size, + const efi_memory_desc_t *md); + /** * efi_range_is_wc - check the WC bit on an address range * @start: starting kvirt address -- cgit v1.2.3 From 6d80dba1c9fe4316ef626980102b92fa30c7845a Mon Sep 17 00:00:00 2001 From: Matt Fleming Date: Tue, 30 Sep 2014 21:58:52 +0100 Subject: efi: Provide a non-blocking SetVariable() operation There are some circumstances that call for trying to write an EFI variable in a non-blocking way. One such scenario is when writing pstore data in efi_pstore_write() via the pstore_dump() kdump callback. Now that we have an EFI runtime spinlock we need a way of aborting if there is contention instead of spinning, since when writing pstore data from the kdump callback, the runtime lock may already be held by the CPU that's running the callback if we crashed in the middle of an EFI variable operation. The situation is sufficiently special that a new EFI variable operation is warranted. Introduce ->set_variable_nonblocking() for this use case. It is an optional EFI backend operation, and need only be implemented by those backends that usually acquire locks to serialize access to EFI variables, as is the case for virt_efi_set_variable() where we now grab the EFI runtime spinlock. Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Ard Biesheuvel Cc: Matthew Garrett Signed-off-by: Matt Fleming --- drivers/firmware/efi/runtime-wrappers.c | 19 +++++++++++++ drivers/firmware/efi/vars.c | 47 +++++++++++++++++++++++++++++++++ include/linux/efi.h | 6 +++++ 3 files changed, 72 insertions(+) (limited to 'include') diff --git a/drivers/firmware/efi/runtime-wrappers.c b/drivers/firmware/efi/runtime-wrappers.c index 9694cba665c4..4349206198b2 100644 --- a/drivers/firmware/efi/runtime-wrappers.c +++ b/drivers/firmware/efi/runtime-wrappers.c @@ -200,6 +200,24 @@ static efi_status_t virt_efi_set_variable(efi_char16_t *name, return status; } +static efi_status_t +virt_efi_set_variable_nonblocking(efi_char16_t *name, efi_guid_t *vendor, + u32 attr, unsigned long data_size, + void *data) +{ + unsigned long flags; + efi_status_t status; + + if (!spin_trylock_irqsave(&efi_runtime_lock, flags)) + return EFI_NOT_READY; + + status = efi_call_virt(set_variable, name, vendor, attr, data_size, + data); + spin_unlock_irqrestore(&efi_runtime_lock, flags); + return status; +} + + static efi_status_t virt_efi_query_variable_info(u32 attr, u64 *storage_space, u64 *remaining_space, @@ -287,6 +305,7 @@ void efi_native_runtime_setup(void) efi.get_variable = virt_efi_get_variable; efi.get_next_variable = virt_efi_get_next_variable; efi.set_variable = virt_efi_set_variable; + efi.set_variable_nonblocking = virt_efi_set_variable_nonblocking; efi.get_next_high_mono_count = virt_efi_get_next_high_mono_count; efi.reset_system = virt_efi_reset_system; efi.query_variable_info = virt_efi_query_variable_info; diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c index 1fa724f31b0e..fa3c66bdc1e5 100644 --- a/drivers/firmware/efi/vars.c +++ b/drivers/firmware/efi/vars.c @@ -595,6 +595,39 @@ int efivar_entry_set(struct efivar_entry *entry, u32 attributes, } EXPORT_SYMBOL_GPL(efivar_entry_set); +/* + * efivar_entry_set_nonblocking - call set_variable_nonblocking() + * + * This function is guaranteed to not block and is suitable for calling + * from crash/panic handlers. + * + * Crucially, this function will not block if it cannot acquire + * __efivars->lock. Instead, it returns -EBUSY. + */ +static int +efivar_entry_set_nonblocking(efi_char16_t *name, efi_guid_t vendor, + u32 attributes, unsigned long size, void *data) +{ + const struct efivar_operations *ops = __efivars->ops; + unsigned long flags; + efi_status_t status; + + if (!spin_trylock_irqsave(&__efivars->lock, flags)) + return -EBUSY; + + status = check_var_size(attributes, size + ucs2_strsize(name, 1024)); + if (status != EFI_SUCCESS) { + spin_unlock_irqrestore(&__efivars->lock, flags); + return -ENOSPC; + } + + status = ops->set_variable_nonblocking(name, &vendor, attributes, + size, data); + + spin_unlock_irqrestore(&__efivars->lock, flags); + return efi_status_to_err(status); +} + /** * efivar_entry_set_safe - call set_variable() if enough space in firmware * @name: buffer containing the variable name @@ -622,6 +655,20 @@ int efivar_entry_set_safe(efi_char16_t *name, efi_guid_t vendor, u32 attributes, if (!ops->query_variable_store) return -ENOSYS; + /* + * If the EFI variable backend provides a non-blocking + * ->set_variable() operation and we're in a context where we + * cannot block, then we need to use it to avoid live-locks, + * since the implication is that the regular ->set_variable() + * will block. + * + * If no ->set_variable_nonblocking() is provided then + * ->set_variable() is assumed to be non-blocking. + */ + if (!block && ops->set_variable_nonblocking) + return efivar_entry_set_nonblocking(name, vendor, attributes, + size, data); + if (!block) { if (!spin_trylock_irqsave(&__efivars->lock, flags)) return -EBUSY; diff --git a/include/linux/efi.h b/include/linux/efi.h index 78b29b133e14..0949f9c7e872 100644 --- a/include/linux/efi.h +++ b/include/linux/efi.h @@ -503,6 +503,10 @@ typedef efi_status_t efi_get_next_variable_t (unsigned long *name_size, efi_char typedef efi_status_t efi_set_variable_t (efi_char16_t *name, efi_guid_t *vendor, u32 attr, unsigned long data_size, void *data); +typedef efi_status_t +efi_set_variable_nonblocking_t(efi_char16_t *name, efi_guid_t *vendor, + u32 attr, unsigned long data_size, void *data); + typedef efi_status_t efi_get_next_high_mono_count_t (u32 *count); typedef void efi_reset_system_t (int reset_type, efi_status_t status, unsigned long data_size, efi_char16_t *data); @@ -822,6 +826,7 @@ extern struct efi { efi_get_variable_t *get_variable; efi_get_next_variable_t *get_next_variable; efi_set_variable_t *set_variable; + efi_set_variable_nonblocking_t *set_variable_nonblocking; efi_query_variable_info_t *query_variable_info; efi_update_capsule_t *update_capsule; efi_query_capsule_caps_t *query_capsule_caps; @@ -1042,6 +1047,7 @@ struct efivar_operations { efi_get_variable_t *get_variable; efi_get_next_variable_t *get_next_variable; efi_set_variable_t *set_variable; + efi_set_variable_nonblocking_t *set_variable_nonblocking; efi_query_variable_store_t *query_variable_store; }; -- cgit v1.2.3