diff options
| -rw-r--r-- | Documentation/acpi/initrd_table_override.txt | 94 | ||||
| -rw-r--r-- | arch/x86/kernel/acpi/boot.c | 6 | ||||
| -rw-r--r-- | arch/x86/kernel/setup.c | 4 | ||||
| -rw-r--r-- | drivers/acpi/Kconfig | 9 | ||||
| -rw-r--r-- | drivers/acpi/osl.c | 202 | ||||
| -rw-r--r-- | include/linux/acpi.h | 16 | ||||
| -rw-r--r-- | include/linux/earlycpio.h | 17 | ||||
| -rw-r--r-- | lib/Makefile | 3 | ||||
| -rw-r--r-- | lib/earlycpio.c | 145 |
9 files changed, 484 insertions, 12 deletions
diff --git a/Documentation/acpi/initrd_table_override.txt b/Documentation/acpi/initrd_table_override.txt new file mode 100644 index 000000000000..35c3f5415476 --- /dev/null +++ b/Documentation/acpi/initrd_table_override.txt @@ -0,0 +1,94 @@ +Overriding ACPI tables via initrd +================================= + +1) Introduction (What is this about) +2) What is this for +3) How does it work +4) References (Where to retrieve userspace tools) + +1) What is this about +--------------------- + +If the ACPI_INITRD_TABLE_OVERRIDE compile option is true, it is possible to +override nearly any ACPI table provided by the BIOS with an instrumented, +modified one. + +For a full list of ACPI tables that can be overridden, take a look at +the char *table_sigs[MAX_ACPI_SIGNATURE]; definition in drivers/acpi/osl.c +All ACPI tables iasl (Intel's ACPI compiler and disassembler) knows should +be overridable, except: + - ACPI_SIG_RSDP (has a signature of 6 bytes) + - ACPI_SIG_FACS (does not have an ordinary ACPI table header) +Both could get implemented as well. + + +2) What is this for +------------------- + +Please keep in mind that this is a debug option. +ACPI tables should not get overridden for productive use. +If BIOS ACPI tables are overridden the kernel will get tainted with the +TAINT_OVERRIDDEN_ACPI_TABLE flag. +Complain to your platform/BIOS vendor if you find a bug which is so sever +that a workaround is not accepted in the Linux kernel. + +Still, it can and should be enabled in any kernel, because: + - There is no functional change with not instrumented initrds + - It provides a powerful feature to easily debug and test ACPI BIOS table + compatibility with the Linux kernel. + + +3) How does it work +------------------- + +# Extract the machine's ACPI tables: +cd /tmp +acpidump >acpidump +acpixtract -a acpidump +# Disassemble, modify and recompile them: +iasl -d *.dat +# For example add this statement into a _PRT (PCI Routing Table) function +# of the DSDT: +Store("HELLO WORLD", debug) +iasl -sa dsdt.dsl +# Add the raw ACPI tables to an uncompressed cpio archive. +# They must be put into a /kernel/firmware/acpi directory inside the +# cpio archive. +# The uncompressed cpio archive must be the first. +# Other, typically compressed cpio archives, must be +# concatenated on top of the uncompressed one. +mkdir -p kernel/firmware/acpi +cp dsdt.aml kernel/firmware/acpi +# A maximum of: #define ACPI_OVERRIDE_TABLES 10 +# tables are currently allowed (see osl.c): +iasl -sa facp.dsl +iasl -sa ssdt1.dsl +cp facp.aml kernel/firmware/acpi +cp ssdt1.aml kernel/firmware/acpi +# Create the uncompressed cpio archive and concatenate the original initrd +# on top: +find kernel | cpio -H newc --create > /boot/instrumented_initrd +cat /boot/initrd >>/boot/instrumented_initrd +# reboot with increased acpi debug level, e.g. boot params: +acpi.debug_level=0x2 acpi.debug_layer=0xFFFFFFFF +# and check your syslog: +[ 1.268089] ACPI: PCI Interrupt Routing Table [\_SB_.PCI0._PRT] +[ 1.272091] [ACPI Debug] String [0x0B] "HELLO WORLD" + +iasl is able to disassemble and recompile quite a lot different, +also static ACPI tables. + + +4) Where to retrieve userspace tools +------------------------------------ + +iasl and acpixtract are part of Intel's ACPICA project: +http://acpica.org/ +and should be packaged by distributions (for example in the acpica package +on SUSE). + +acpidump can be found in Len Browns pmtools: +ftp://kernel.org/pub/linux/kernel/people/lenb/acpi/utils/pmtools/acpidump +This tool is also part of the acpica package on SUSE. +Alternatively, used ACPI tables can be retrieved via sysfs in latest kernels: +/sys/firmware/acpi/tables diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c index e48cafcf92ae..bacf4b0d91f4 100644 --- a/arch/x86/kernel/acpi/boot.c +++ b/arch/x86/kernel/acpi/boot.c @@ -1706,3 +1706,9 @@ int __acpi_release_global_lock(unsigned int *lock) } while (unlikely (val != old)); return old & 0x1; } + +void __init arch_reserve_mem_area(acpi_physical_address addr, size_t size) +{ + e820_add_region(addr, size, E820_ACPI); + update_e820(); +} diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index c228322ca180..23ddd558fbd5 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -952,6 +952,10 @@ void __init setup_arch(char **cmdline_p) reserve_initrd(); +#if defined(CONFIG_ACPI) && defined(CONFIG_BLK_DEV_INITRD) + acpi_initrd_override((void *)initrd_start, initrd_end - initrd_start); +#endif + reserve_crashkernel(); vsmp_init(); diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig index 0300bf612946..38c5078da11d 100644 --- a/drivers/acpi/Kconfig +++ b/drivers/acpi/Kconfig @@ -267,6 +267,15 @@ config ACPI_CUSTOM_DSDT bool default ACPI_CUSTOM_DSDT_FILE != "" +config ACPI_INITRD_TABLE_OVERRIDE + bool "ACPI tables can be passed via uncompressed cpio in initrd" + default n + help + This option provides functionality to override arbitrary ACPI tables + via initrd. No functional change if no ACPI tables are passed via + initrd, therefore it's safe to say Y. + See Documentation/acpi/initrd_table_override.txt for details + config ACPI_BLACKLIST_YEAR int "Disable ACPI for systems before Jan 1st this year" if X86_32 default 0 diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c index 6dc4a2b1e956..3ff267861541 100644 --- a/drivers/acpi/osl.c +++ b/drivers/acpi/osl.c @@ -534,6 +534,137 @@ acpi_os_predefined_override(const struct acpi_predefined_names *init_val, return AE_OK; } +#ifdef CONFIG_ACPI_INITRD_TABLE_OVERRIDE +#include <linux/earlycpio.h> +#include <linux/memblock.h> + +static u64 acpi_tables_addr; +static int all_tables_size; + +/* Copied from acpica/tbutils.c:acpi_tb_checksum() */ +u8 __init acpi_table_checksum(u8 *buffer, u32 length) +{ + u8 sum = 0; + u8 *end = buffer + length; + + while (buffer < end) + sum = (u8) (sum + *(buffer++)); + return sum; +} + +/* All but ACPI_SIG_RSDP and ACPI_SIG_FACS: */ +static const char * const table_sigs[] = { + ACPI_SIG_BERT, ACPI_SIG_CPEP, ACPI_SIG_ECDT, ACPI_SIG_EINJ, + ACPI_SIG_ERST, ACPI_SIG_HEST, ACPI_SIG_MADT, ACPI_SIG_MSCT, + ACPI_SIG_SBST, ACPI_SIG_SLIT, ACPI_SIG_SRAT, ACPI_SIG_ASF, + ACPI_SIG_BOOT, ACPI_SIG_DBGP, ACPI_SIG_DMAR, ACPI_SIG_HPET, + ACPI_SIG_IBFT, ACPI_SIG_IVRS, ACPI_SIG_MCFG, ACPI_SIG_MCHI, + ACPI_SIG_SLIC, ACPI_SIG_SPCR, ACPI_SIG_SPMI, ACPI_SIG_TCPA, + ACPI_SIG_UEFI, ACPI_SIG_WAET, ACPI_SIG_WDAT, ACPI_SIG_WDDT, + ACPI_SIG_WDRT, ACPI_SIG_DSDT, ACPI_SIG_FADT, ACPI_SIG_PSDT, + ACPI_SIG_RSDT, ACPI_SIG_XSDT, ACPI_SIG_SSDT, NULL }; + +/* Non-fatal errors: Affected tables/files are ignored */ +#define INVALID_TABLE(x, path, name) \ + { pr_err("ACPI OVERRIDE: " x " [%s%s]\n", path, name); continue; } + +#define ACPI_HEADER_SIZE sizeof(struct acpi_table_header) + +/* Must not increase 10 or needs code modification below */ +#define ACPI_OVERRIDE_TABLES 10 + +void __init acpi_initrd_override(void *data, size_t size) +{ + int sig, no, table_nr = 0, total_offset = 0; + long offset = 0; + struct acpi_table_header *table; + char cpio_path[32] = "kernel/firmware/acpi/"; + struct cpio_data file; + struct cpio_data early_initrd_files[ACPI_OVERRIDE_TABLES]; + char *p; + + if (data == NULL || size == 0) + return; + + for (no = 0; no < ACPI_OVERRIDE_TABLES; no++) { + file = find_cpio_data(cpio_path, data, size, &offset); + if (!file.data) + break; + + data += offset; + size -= offset; + + if (file.size < sizeof(struct acpi_table_header)) + INVALID_TABLE("Table smaller than ACPI header", + cpio_path, file.name); + + table = file.data; + + for (sig = 0; table_sigs[sig]; sig++) + if (!memcmp(table->signature, table_sigs[sig], 4)) + break; + + if (!table_sigs[sig]) + INVALID_TABLE("Unknown signature", + cpio_path, file.name); + if (file.size != table->length) + INVALID_TABLE("File length does not match table length", + cpio_path, file.name); + if (acpi_table_checksum(file.data, table->length)) + INVALID_TABLE("Bad table checksum", + cpio_path, file.name); + + pr_info("%4.4s ACPI table found in initrd [%s%s][0x%x]\n", + table->signature, cpio_path, file.name, table->length); + + all_tables_size += table->length; + early_initrd_files[table_nr].data = file.data; + early_initrd_files[table_nr].size = file.size; + table_nr++; + } + if (table_nr == 0) + return; + + acpi_tables_addr = + memblock_find_in_range(0, max_low_pfn_mapped << PAGE_SHIFT, + all_tables_size, PAGE_SIZE); + if (!acpi_tables_addr) { + WARN_ON(1); + return; + } + /* + * Only calling e820_add_reserve does not work and the + * tables are invalid (memory got used) later. + * memblock_reserve works as expected and the tables won't get modified. + * But it's not enough on X86 because ioremap will + * complain later (used by acpi_os_map_memory) that the pages + * that should get mapped are not marked "reserved". + * Both memblock_reserve and e820_add_region (via arch_reserve_mem_area) + * works fine. + */ + memblock_reserve(acpi_tables_addr, acpi_tables_addr + all_tables_size); + arch_reserve_mem_area(acpi_tables_addr, all_tables_size); + + p = early_ioremap(acpi_tables_addr, all_tables_size); + + for (no = 0; no < table_nr; no++) { + memcpy(p + total_offset, early_initrd_files[no].data, + early_initrd_files[no].size); + total_offset += early_initrd_files[no].size; + } + early_iounmap(p, all_tables_size); +} +#endif /* CONFIG_ACPI_INITRD_TABLE_OVERRIDE */ + +static void acpi_table_taint(struct acpi_table_header *table) +{ + pr_warn(PREFIX + "Override [%4.4s-%8.8s], this is unsafe: tainting kernel\n", + table->signature, table->oem_table_id); + add_taint(TAINT_OVERRIDDEN_ACPI_TABLE); +} + + acpi_status acpi_os_table_override(struct acpi_table_header * existing_table, struct acpi_table_header ** new_table) @@ -547,24 +678,73 @@ acpi_os_table_override(struct acpi_table_header * existing_table, if (strncmp(existing_table->signature, "DSDT", 4) == 0) *new_table = (struct acpi_table_header *)AmlCode; #endif - if (*new_table != NULL) { - printk(KERN_WARNING PREFIX "Override [%4.4s-%8.8s], " - "this is unsafe: tainting kernel\n", - existing_table->signature, - existing_table->oem_table_id); - add_taint(TAINT_OVERRIDDEN_ACPI_TABLE); - } + if (*new_table != NULL) + acpi_table_taint(existing_table); return AE_OK; } acpi_status acpi_os_physical_table_override(struct acpi_table_header *existing_table, - acpi_physical_address * new_address, - u32 *new_table_length) + acpi_physical_address *address, + u32 *table_length) { - return AE_SUPPORT; -} +#ifndef CONFIG_ACPI_INITRD_TABLE_OVERRIDE + *table_length = 0; + *address = 0; + return AE_OK; +#else + int table_offset = 0; + struct acpi_table_header *table; + + *table_length = 0; + *address = 0; + + if (!acpi_tables_addr) + return AE_OK; + + do { + if (table_offset + ACPI_HEADER_SIZE > all_tables_size) { + WARN_ON(1); + return AE_OK; + } + table = acpi_os_map_memory(acpi_tables_addr + table_offset, + ACPI_HEADER_SIZE); + + if (table_offset + table->length > all_tables_size) { + acpi_os_unmap_memory(table, ACPI_HEADER_SIZE); + WARN_ON(1); + return AE_OK; + } + + table_offset += table->length; + + if (memcmp(existing_table->signature, table->signature, 4)) { + acpi_os_unmap_memory(table, + ACPI_HEADER_SIZE); + continue; + } + + /* Only override tables with matching oem id */ + if (memcmp(table->oem_table_id, existing_table->oem_table_id, + ACPI_OEM_TABLE_ID_SIZE)) { + acpi_os_unmap_memory(table, + ACPI_HEADER_SIZE); + continue; + } + + table_offset -= table->length; + *table_length = table->length; + acpi_os_unmap_memory(table, ACPI_HEADER_SIZE); + *address = acpi_tables_addr + table_offset; + break; + } while (table_offset + ACPI_HEADER_SIZE < all_tables_size); + + if (*address != 0) + acpi_table_taint(existing_table); + return AE_OK; +#endif +} static irqreturn_t acpi_irq(int irq, void *dev_id) { diff --git a/include/linux/acpi.h b/include/linux/acpi.h index c33fa3ce9b7c..3994d7790b23 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -78,6 +78,14 @@ typedef int (*acpi_table_handler) (struct acpi_table_header *table); typedef int (*acpi_table_entry_handler) (struct acpi_subtable_header *header, const unsigned long end); +#ifdef CONFIG_ACPI_INITRD_TABLE_OVERRIDE +void acpi_initrd_override(void *data, size_t size); +#else +static inline void acpi_initrd_override(void *data, size_t size) +{ +} +#endif + char * __acpi_map_table (unsigned long phys_addr, unsigned long size); void __acpi_unmap_table(char *map, unsigned long size); int early_acpi_boot_init(void); @@ -479,6 +487,14 @@ void acpi_os_set_prepare_sleep(int (*func)(u8 sleep_state, acpi_status acpi_os_prepare_sleep(u8 sleep_state, u32 pm1a_control, u32 pm1b_control); +#ifdef CONFIG_X86 +void arch_reserve_mem_area(acpi_physical_address addr, size_t size); +#else +static inline void arch_reserve_mem_area(acpi_physical_address addr, + size_t size) +{ +} +#endif /* CONFIG_X86 */ #else #define acpi_os_set_prepare_sleep(func, pm1a_ctrl, pm1b_ctrl) do { } while (0) #endif diff --git a/include/linux/earlycpio.h b/include/linux/earlycpio.h new file mode 100644 index 000000000000..111f46d83d00 --- /dev/null +++ b/include/linux/earlycpio.h @@ -0,0 +1,17 @@ +#ifndef _LINUX_EARLYCPIO_H +#define _LINUX_EARLYCPIO_H + +#include <linux/types.h> + +#define MAX_CPIO_FILE_NAME 18 + +struct cpio_data { + void *data; + size_t size; + char name[MAX_CPIO_FILE_NAME]; +}; + +struct cpio_data find_cpio_data(const char *path, void *data, size_t len, + long *offset); + +#endif /* _LINUX_EARLYCPIO_H */ diff --git a/lib/Makefile b/lib/Makefile index e3723c7527da..e2152fa7ff4d 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -12,7 +12,8 @@ lib-y := ctype.o string.o vsprintf.o cmdline.o \ idr.o int_sqrt.o extable.o \ sha1.o md5.o irq_regs.o reciprocal_div.o argv_split.o \ proportions.o flex_proportions.o prio_heap.o ratelimit.o show_mem.o \ - is_single_threaded.o plist.o decompress.o kobject_uevent.o + is_single_threaded.o plist.o decompress.o kobject_uevent.o \ + earlycpio.o lib-$(CONFIG_MMU) += ioremap.o lib-$(CONFIG_SMP) += cpumask.o diff --git a/lib/earlycpio.c b/lib/earlycpio.c new file mode 100644 index 000000000000..8078ef49cb79 --- /dev/null +++ b/lib/earlycpio.c @@ -0,0 +1,145 @@ +/* ----------------------------------------------------------------------- * + * + * Copyright 2012 Intel Corporation; author H. Peter Anvin + * + * This file is part of the Linux kernel, and is made available + * under the terms of the GNU General Public License version 2, as + * published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * ----------------------------------------------------------------------- */ + +/* + * earlycpio.c + * + * Find a specific cpio member; must precede any compressed content. + * This is used to locate data items in the initramfs used by the + * kernel itself during early boot (before the main initramfs is + * decompressed.) It is the responsibility of the initramfs creator + * to ensure that these items are uncompressed at the head of the + * blob. Depending on the boot loader or package tool that may be a + * separate file or part of the same file. + */ + +#include <linux/earlycpio.h> +#include <linux/kernel.h> +#include <linux/string.h> + +enum cpio_fields { + C_MAGIC, + C_INO, + C_MODE, + C_UID, + C_GID, + C_NLINK, + C_MTIME, + C_FILESIZE, + C_MAJ, + C_MIN, + C_RMAJ, + C_RMIN, + C_NAMESIZE, + C_CHKSUM, + C_NFIELDS +}; + +/** + * cpio_data find_cpio_data - Search for files in an uncompressed cpio + * @path: The directory to search for, including a slash at the end + * @data: Pointer to the the cpio archive or a header inside + * @len: Remaining length of the cpio based on data pointer + * @offset: When a matching file is found, this is the offset to the + * beginning of the cpio. It can be used to iterate through + * the cpio to find all files inside of a directory path + * + * @return: struct cpio_data containing the address, length and + * filename (with the directory path cut off) of the found file. + * If you search for a filename and not for files in a directory, + * pass the absolute path of the filename in the cpio and make sure + * the match returned an empty filename string. + */ + +struct cpio_data __cpuinit find_cpio_data(const char *path, void *data, + size_t len, long *offset) +{ + const size_t cpio_header_len = 8*C_NFIELDS - 2; + struct cpio_data cd = { NULL, 0, "" }; + const char *p, *dptr, *nptr; + unsigned int ch[C_NFIELDS], *chp, v; + unsigned char c, x; + size_t mypathsize = strlen(path); + int i, j; + + p = data; + + while (len > cpio_header_len) { + if (!*p) { + /* All cpio headers need to be 4-byte aligned */ + p += 4; + len -= 4; + continue; + } + + j = 6; /* The magic field is only 6 characters */ + chp = ch; + for (i = C_NFIELDS; i; i--) { + v = 0; + while (j--) { + v <<= 4; + c = *p++; + + x = c - '0'; + if (x < 10) { + v += x; + continue; + } + + x = (c | 0x20) - 'a'; + if (x < 6) { + v += x + 10; + continue; + } + + goto quit; /* Invalid hexadecimal */ + } + *chp++ = v; + j = 8; /* All other fields are 8 characters */ + } + + if ((ch[C_MAGIC] - 0x070701) > 1) + goto quit; /* Invalid magic */ + + len -= cpio_header_len; + + dptr = PTR_ALIGN(p + ch[C_NAMESIZE], 4); + nptr = PTR_ALIGN(dptr + ch[C_FILESIZE], 4); + + if (nptr > p + len || dptr < p || nptr < dptr) + goto quit; /* Buffer overrun */ + + if ((ch[C_MODE] & 0170000) == 0100000 && + ch[C_NAMESIZE] >= mypathsize && + !memcmp(p, path, mypathsize)) { + *offset = (long)nptr - (long)data; + if (ch[C_NAMESIZE] - mypathsize >= MAX_CPIO_FILE_NAME) { + pr_warn( + "File %s exceeding MAX_CPIO_FILE_NAME [%d]\n", + p, MAX_CPIO_FILE_NAME); + } + strlcpy(cd.name, p + mypathsize, MAX_CPIO_FILE_NAME); + + cd.data = (void *)dptr; + cd.size = ch[C_FILESIZE]; + return cd; /* Found it! */ + } + len -= (nptr - p); + p = nptr; + } + +quit: + return cd; +} |