diff options
| -rw-r--r-- | Documentation/kernel-parameters.txt | 23 | ||||
| -rw-r--r-- | arch/x86/Kconfig | 50 | ||||
| -rw-r--r-- | arch/x86/kernel/setup.c | 196 | ||||
| -rw-r--r-- | arch/x86/mm/init_32.c | 2 | ||||
| -rw-r--r-- | arch/x86/mm/init_64.c | 2 | ||||
| -rw-r--r-- | drivers/base/power/main.c | 1 | ||||
| -rw-r--r-- | include/linux/kernel.h | 17 |
7 files changed, 289 insertions, 2 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 25efbaf1f59..bade177ab73 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1231,6 +1231,29 @@ and is between 256 and 4096 characters. It is defined in the file or memmap=0x10000$0x18690000 + memory_corruption_check=0/1 [X86] + Some BIOSes seem to corrupt the first 64k of + memory when doing things like suspend/resume. + Setting this option will scan the memory + looking for corruption. Enabling this will + both detect corruption and prevent the kernel + from using the memory being corrupted. + However, its intended as a diagnostic tool; if + repeatable BIOS-originated corruption always + affects the same memory, you can use memmap= + to prevent the kernel from using that memory. + + memory_corruption_check_size=size [X86] + By default it checks for corruption in the low + 64k, making this memory unavailable for normal + use. Use this parameter to scan for + corruption in more or less memory. + + memory_corruption_check_period=seconds [X86] + By default it checks for corruption every 60 + seconds. Use this parameter to check at some + other rate. 0 disables periodic checking. + memtest= [KNL,X86] Enable memtest Format: <integer> range: 0,4 : pattern number diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 44d4f2130d0..25e2f7a20d6 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1061,6 +1061,56 @@ config HIGHPTE low memory. Setting this option will put user-space page table entries in high memory. +config X86_CHECK_BIOS_CORRUPTION + bool "Check for low memory corruption" + help + Periodically check for memory corruption in low memory, which + is suspected to be caused by BIOS. Even when enabled in the + configuration, it is disabled at runtime. Enable it by + setting "memory_corruption_check=1" on the kernel command + line. By default it scans the low 64k of memory every 60 + seconds; see the memory_corruption_check_size and + memory_corruption_check_period parameters in + Documentation/kernel-parameters.txt to adjust this. + + When enabled with the default parameters, this option has + almost no overhead, as it reserves a relatively small amount + of memory and scans it infrequently. It both detects corruption + and prevents it from affecting the running system. + + It is, however, intended as a diagnostic tool; if repeatable + BIOS-originated corruption always affects the same memory, + you can use memmap= to prevent the kernel from using that + memory. + +config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK + bool "Set the default setting of memory_corruption_check" + depends on X86_CHECK_BIOS_CORRUPTION + default y + help + Set whether the default state of memory_corruption_check is + on or off. + +config X86_RESERVE_LOW_64K + bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen" + default y + help + Reserve the first 64K of physical RAM on BIOSes that are known + to potentially corrupt that memory range. A numbers of BIOSes are + known to utilize this area during suspend/resume, so it must not + be used by the kernel. + + Set this to N if you are absolutely sure that you trust the BIOS + to get all its memory reservations and usages right. + + If you have doubts about the BIOS (e.g. suspend/resume does not + work or there's kernel crashes after certain hardware hotplug + events) and it's not AMI or Phoenix, then you might want to enable + X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical + corruption patterns. + + Say Y if unsure. + config MATH_EMULATION bool prompt "Math emulation" if X86_32 diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index 46c98efbbf8..21b8e0a5978 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -582,6 +582,190 @@ static struct x86_quirks default_x86_quirks __initdata; struct x86_quirks *x86_quirks __initdata = &default_x86_quirks; /* + * Some BIOSes seem to corrupt the low 64k of memory during events + * like suspend/resume and unplugging an HDMI cable. Reserve all + * remaining free memory in that area and fill it with a distinct + * pattern. + */ +#ifdef CONFIG_X86_CHECK_BIOS_CORRUPTION +#define MAX_SCAN_AREAS 8 + +static int __read_mostly memory_corruption_check = -1; + +static unsigned __read_mostly corruption_check_size = 64*1024; +static unsigned __read_mostly corruption_check_period = 60; /* seconds */ + +static struct e820entry scan_areas[MAX_SCAN_AREAS]; +static int num_scan_areas; + + +static int set_corruption_check(char *arg) +{ + char *end; + + memory_corruption_check = simple_strtol(arg, &end, 10); + + return (*end == 0) ? 0 : -EINVAL; +} +early_param("memory_corruption_check", set_corruption_check); + +static int set_corruption_check_period(char *arg) +{ + char *end; + + corruption_check_period = simple_strtoul(arg, &end, 10); + + return (*end == 0) ? 0 : -EINVAL; +} +early_param("memory_corruption_check_period", set_corruption_check_period); + +static int set_corruption_check_size(char *arg) +{ + char *end; + unsigned size; + + size = memparse(arg, &end); + + if (*end == '\0') + corruption_check_size = size; + + return (size == corruption_check_size) ? 0 : -EINVAL; +} +early_param("memory_corruption_check_size", set_corruption_check_size); + + +static void __init setup_bios_corruption_check(void) +{ + u64 addr = PAGE_SIZE; /* assume first page is reserved anyway */ + + if (memory_corruption_check == -1) { + memory_corruption_check = +#ifdef CONFIG_X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK + 1 +#else + 0 +#endif + ; + } + + if (corruption_check_size == 0) + memory_corruption_check = 0; + + if (!memory_corruption_check) + return; + + corruption_check_size = round_up(corruption_check_size, PAGE_SIZE); + + while(addr < corruption_check_size && num_scan_areas < MAX_SCAN_AREAS) { + u64 size; + addr = find_e820_area_size(addr, &size, PAGE_SIZE); + + if (addr == 0) + break; + + if ((addr + size) > corruption_check_size) + size = corruption_check_size - addr; + + if (size == 0) + break; + + e820_update_range(addr, size, E820_RAM, E820_RESERVED); + scan_areas[num_scan_areas].addr = addr; + scan_areas[num_scan_areas].size = size; + num_scan_areas++; + + /* Assume we've already mapped this early memory */ + memset(__va(addr), 0, size); + + addr += size; + } + + printk(KERN_INFO "Scanning %d areas for low memory corruption\n", + num_scan_areas); + update_e820(); +} + +static struct timer_list periodic_check_timer; + +void check_for_bios_corruption(void) +{ + int i; + int corruption = 0; + + if (!memory_corruption_check) + return; + + for(i = 0; i < num_scan_areas; i++) { + unsigned long *addr = __va(scan_areas[i].addr); + unsigned long size = scan_areas[i].size; + + for(; size; addr++, size -= sizeof(unsigned long)) { + if (!*addr) + continue; + printk(KERN_ERR "Corrupted low memory at %p (%lx phys) = %08lx\n", + addr, __pa(addr), *addr); + corruption = 1; + *addr = 0; + } + } + + WARN(corruption, KERN_ERR "Memory corruption detected in low memory\n"); +} + +static void periodic_check_for_corruption(unsigned long data) +{ + check_for_bios_corruption(); + mod_timer(&periodic_check_timer, round_jiffies(jiffies + corruption_check_period*HZ)); +} + +void start_periodic_check_for_corruption(void) +{ + if (!memory_corruption_check || corruption_check_period == 0) + return; + + printk(KERN_INFO "Scanning for low memory corruption every %d seconds\n", + corruption_check_period); + + init_timer(&periodic_check_timer); + periodic_check_timer.function = &periodic_check_for_corruption; + periodic_check_for_corruption(0); +} +#endif + +static int __init dmi_low_memory_corruption(const struct dmi_system_id *d) +{ + printk(KERN_NOTICE + "%s detected: BIOS may corrupt low RAM, working it around.\n", + d->ident); + + e820_update_range(0, 0x10000, E820_RAM, E820_RESERVED); + sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map); + + return 0; +} + +/* List of systems that have known low memory corruption BIOS problems */ +static struct dmi_system_id __initdata bad_bios_dmi_table[] = { +#ifdef CONFIG_X86_RESERVE_LOW_64K + { + .callback = dmi_low_memory_corruption, + .ident = "AMI BIOS", + .matches = { + DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."), + }, + }, + { + .callback = dmi_low_memory_corruption, + .ident = "Phoenix BIOS", + .matches = { + DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies, LTD"), + }, + }, +#endif + {} +}; + +/* * Determine if we were loaded by an EFI loader. If so, then we have also been * passed the efi memmap, systab, etc., so we should use these data structures * for initialization. Note, the efi init code path is determined by the @@ -715,6 +899,10 @@ void __init setup_arch(char **cmdline_p) finish_e820_parsing(); + dmi_scan_machine(); + + dmi_check_system(bad_bios_dmi_table); + #ifdef CONFIG_X86_32 probe_roms(); #endif @@ -771,6 +959,10 @@ void __init setup_arch(char **cmdline_p) high_memory = (void *)__va(max_pfn * PAGE_SIZE - 1) + 1; #endif +#ifdef CONFIG_X86_CHECK_BIOS_CORRUPTION + setup_bios_corruption_check(); +#endif + /* max_pfn_mapped is updated here */ max_low_pfn_mapped = init_memory_mapping(0, max_low_pfn<<PAGE_SHIFT); max_pfn_mapped = max_low_pfn_mapped; @@ -799,8 +991,6 @@ void __init setup_arch(char **cmdline_p) vsmp_init(); #endif - dmi_scan_machine(); - io_delay_init(); /* @@ -903,3 +1093,5 @@ void __init setup_arch(char **cmdline_p) #endif #endif } + + diff --git a/arch/x86/mm/init_32.c b/arch/x86/mm/init_32.c index c3789bb1930..7e05462ffb1 100644 --- a/arch/x86/mm/init_32.c +++ b/arch/x86/mm/init_32.c @@ -969,6 +969,8 @@ void __init mem_init(void) int codesize, reservedpages, datasize, initsize; int tmp; + start_periodic_check_for_corruption(); + #ifdef CONFIG_FLATMEM BUG_ON(!mem_map); #endif diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index 83e13f2d53d..d84d3e91d34 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -881,6 +881,8 @@ void __init mem_init(void) { long codesize, reservedpages, datasize, initsize; + start_periodic_check_for_corruption(); + pci_iommu_alloc(); /* clear_bss() already clear the empty_zero_page */ diff --git a/drivers/base/power/main.c b/drivers/base/power/main.c index 273a944d404..bf6d3554e50 100644 --- a/drivers/base/power/main.c +++ b/drivers/base/power/main.c @@ -254,6 +254,7 @@ static char *pm_verb(int event) static void pm_dev_dbg(struct device *dev, pm_message_t state, char *info) { + check_for_bios_corruption(); dev_dbg(dev, "%s%s%s\n", info, pm_verb(state.event), ((state.event & PM_EVENT_SLEEP) && device_may_wakeup(dev)) ? ", may wakeup" : ""); diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 2651f805ba6..50873b21178 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -240,6 +240,23 @@ extern const char *print_tainted(void); extern void add_taint(unsigned); extern int root_mountflags; +#ifdef CONFIG_X86_CHECK_BIOS_CORRUPTION +/* + * This is obviously not a great place for this, but we want to be + * able to scatter it around anywhere in the kernel. + */ +void check_for_bios_corruption(void); +void start_periodic_check_for_corruption(void); +#else +static inline void check_for_bios_corruption(void) +{ +} + +static inline void start_periodic_check_for_corruption(void) +{ +} +#endif + /* Values used for system_state */ extern enum system_states { SYSTEM_BOOTING, |