APEI Error INJection
~~~~~~~~~~~~~~~~~~~~
-EINJ provides a hardware error injection mechanism
-It is very useful for debugging and testing of other APEI and RAS features.
+EINJ provides a hardware error injection mechanism. It is very useful
+for debugging and testing APEI and RAS features in general.
-To use EINJ, make sure the following are enabled in your kernel
+You need to check whether your BIOS supports EINJ first. For that, look
+for early boot messages similar to this one:
+
+ACPI: EINJ 0x000000007370A000 000150 (v01 INTEL 00000001 INTL 00000001)
+
+which shows that the BIOS is exposing an EINJ table - it is the
+mechanism through which the injection is done.
+
+Alternatively, look in /sys/firmware/acpi/tables for an "EINJ" file,
+which is a different representation of the same thing.
+
+It doesn't necessarily mean that EINJ is not supported if those above
+don't exist: before you give up, go into BIOS setup to see if the BIOS
+has an option to enable error injection. Look for something called WHEA
+or similar. Often, you need to enable an ACPI5 support option prior, in
+order to see the APEI,EINJ,... functionality supported and exposed by
+the BIOS menu.
+
+To use EINJ, make sure the following are options enabled in your kernel
configuration:
CONFIG_DEBUG_FS
CONFIG_ACPI_APEI
CONFIG_ACPI_APEI_EINJ
-The user interface of EINJ is debug file system, under the
-directory apei/einj. The following files are provided.
+The EINJ user interface is in <debugfs mount point>/apei/einj.
+
+The following files belong to it:
- available_error_type
- Reading this file returns the error injection capability of the
- platform, that is, which error types are supported. The error type
- definition is as follow, the left field is the error type value, the
- right field is error description.
-
- 0x00000001 Processor Correctable
- 0x00000002 Processor Uncorrectable non-fatal
- 0x00000004 Processor Uncorrectable fatal
- 0x00000008 Memory Correctable
- 0x00000010 Memory Uncorrectable non-fatal
- 0x00000020 Memory Uncorrectable fatal
- 0x00000040 PCI Express Correctable
- 0x00000080 PCI Express Uncorrectable fatal
- 0x00000100 PCI Express Uncorrectable non-fatal
- 0x00000200 Platform Correctable
- 0x00000400 Platform Uncorrectable non-fatal
- 0x00000800 Platform Uncorrectable fatal
-
- The format of file contents are as above, except there are only the
- available error type lines.
+
+ This file shows which error types are supported:
+
+ Error Type Value Error Description
+ ================ =================
+ 0x00000001 Processor Correctable
+ 0x00000002 Processor Uncorrectable non-fatal
+ 0x00000004 Processor Uncorrectable fatal
+ 0x00000008 Memory Correctable
+ 0x00000010 Memory Uncorrectable non-fatal
+ 0x00000020 Memory Uncorrectable fatal
+ 0x00000040 PCI Express Correctable
+ 0x00000080 PCI Express Uncorrectable fatal
+ 0x00000100 PCI Express Uncorrectable non-fatal
+ 0x00000200 Platform Correctable
+ 0x00000400 Platform Uncorrectable non-fatal
+ 0x00000800 Platform Uncorrectable fatal
+
+ The format of the file contents are as above, except present are only
+ the available error types.
- error_type
- This file is used to set the error type value. The error type value
- is defined in "available_error_type" description.
+
+ Set the value of the error type being injected. Possible error types
+ are defined in the file available_error_type above.
- error_inject
- Write any integer to this file to trigger the error
- injection. Before this, please specify all necessary error
- parameters.
+
+ Write any integer to this file to trigger the error injection. Make
+ sure you have specified all necessary error parameters, i.e. this
+ write should be the last step when injecting errors.
- flags
- Present for kernel version 3.13 and above. Used to specify which
- of param{1..4} are valid and should be used by BIOS during injection.
- Value is a bitmask as specified in ACPI5.0 spec for the
+
+ Present for kernel versions 3.13 and above. Used to specify which
+ of param{1..4} are valid and should be used by the firmware during
+ injection. Value is a bitmask as specified in ACPI5.0 spec for the
SET_ERROR_TYPE_WITH_ADDRESS data structure:
- Bit 0 - Processor APIC field valid (see param3 below)
- Bit 1 - Memory address and mask valid (param1 and param2)
- Bit 2 - PCIe (seg,bus,dev,fn) valid (param4 below)
- If set to zero, legacy behaviour is used where the type of injection
- specifies just one bit set, and param1 is multiplexed.
+
+ Bit 0 - Processor APIC field valid (see param3 below).
+ Bit 1 - Memory address and mask valid (param1 and param2).
+ Bit 2 - PCIe (seg,bus,dev,fn) valid (see param4 below).
+
+ If set to zero, legacy behavior is mimicked where the type of
+ injection specifies just one bit set, and param1 is multiplexed.
- param1
- This file is used to set the first error parameter value. Effect of
- parameter depends on error_type specified. For example, if error
- type is memory related type, the param1 should be a valid physical
- memory address. [Unless "flag" is set - see above]
+
+ This file is used to set the first error parameter value. Its effect
+ depends on the error type specified in error_type. For example, if
+ error type is memory related type, the param1 should be a valid
+ physical memory address. [Unless "flag" is set - see above]
- param2
- This file is used to set the second error parameter value. Effect of
- parameter depends on error_type specified. For example, if error
- type is memory related type, the param2 should be a physical memory
- address mask. Linux requires page or narrower granularity, say,
- 0xfffffffffffff000.
+
+ Same use as param1 above. For example, if error type is of memory
+ related type, then param2 should be a physical memory address mask.
+ Linux requires page or narrower granularity, say, 0xfffffffffffff000.
- param3
- Used when the 0x1 bit is set in "flag" to specify the APIC id
+
+ Used when the 0x1 bit is set in "flags" to specify the APIC id
- param4
- Used when the 0x4 bit is set in "flag" to specify target PCIe device
+ Used when the 0x4 bit is set in "flags" to specify target PCIe device
- notrigger
- The EINJ mechanism is a two step process. First inject the error, then
- perform some actions to trigger it. Setting "notrigger" to 1 skips the
- trigger phase, which *may* allow the user to cause the error in some other
- context by a simple access to the cpu, memory location, or device that is
- the target of the error injection. Whether this actually works depends
- on what operations the BIOS actually includes in the trigger phase.
-
-BIOS versions based in the ACPI 4.0 specification have limited options
-to control where the errors are injected. Your BIOS may support an
-extension (enabled with the param_extension=1 module parameter, or
-boot command line einj.param_extension=1). This allows the address
-and mask for memory injections to be specified by the param1 and
-param2 files in apei/einj.
-
-BIOS versions using the ACPI 5.0 specification have more control over
-the target of the injection. For processor related errors (type 0x1,
-0x2 and 0x4) the APICID of the target should be provided using the
-param1 file in apei/einj. For memory errors (type 0x8, 0x10 and 0x20)
-the address is set using param1 with a mask in param2 (0x0 is equivalent
-to all ones). For PCI express errors (type 0x40, 0x80 and 0x100) the
-segment, bus, device and function are specified using param1:
+
+ The error injection mechanism is a two-step process. First inject the
+ error, then perform some actions to trigger it. Setting "notrigger"
+ to 1 skips the trigger phase, which *may* allow the user to cause the
+ error in some other context by a simple access to the CPU, memory
+ location, or device that is the target of the error injection. Whether
+ this actually works depends on what operations the BIOS actually
+ includes in the trigger phase.
+
+BIOS versions based on the ACPI 4.0 specification have limited options
+in controlling where the errors are injected. Your BIOS may support an
+extension (enabled with the param_extension=1 module parameter, or boot
+command line einj.param_extension=1). This allows the address and mask
+for memory injections to be specified by the param1 and param2 files in
+apei/einj.
+
+BIOS versions based on the ACPI 5.0 specification have more control over
+the target of the injection. For processor-related errors (type 0x1, 0x2
+and 0x4), you can set flags to 0x3 (param3 for bit 0, and param1 and
+param2 for bit 1) so that you have more information added to the error
+signature being injected. The actual data passed is this:
+
+ memory_address = param1;
+ memory_address_range = param2;
+ apicid = param3;
+ pcie_sbdf = param4;
+
+For memory errors (type 0x8, 0x10 and 0x20) the address is set using
+param1 with a mask in param2 (0x0 is equivalent to all ones). For PCI
+express errors (type 0x40, 0x80 and 0x100) the segment, bus, device and
+function are specified using param1:
31 24 23 16 15 11 10 8 7 0
+-------------------------------------------------+
| segment | bus | device | function | reserved |
+-------------------------------------------------+
-An ACPI 5.0 BIOS may also allow vendor specific errors to be injected.
+Anyway, you get the idea, if there's doubt just take a look at the code
+in drivers/acpi/apei/einj.c.
+
+An ACPI 5.0 BIOS may also allow vendor-specific errors to be injected.
In this case a file named vendor will contain identifying information
from the BIOS that hopefully will allow an application wishing to use
-the vendor specific extension to tell that they are running on a BIOS
+the vendor-specific extension to tell that they are running on a BIOS
that supports it. All vendor extensions have the 0x80000000 bit set in
error_type. A file vendor_flags controls the interpretation of param1
and param2 (1 = PROCESSOR, 2 = MEMORY, 4 = PCI). See your BIOS vendor
documentation for details (and expect changes to this API if vendors
creativity in using this feature expands beyond our expectations).
-Example:
+
+An error injection example:
+
# cd /sys/kernel/debug/apei/einj
# cat available_error_type # See which errors can be injected
0x00000002 Processor Uncorrectable non-fatal
0x00000008 Memory Correctable
0x00000010 Memory Uncorrectable non-fatal
# echo 0x12345000 > param1 # Set memory address for injection
-# echo 0xfffffffffffff000 > param2 # Mask - anywhere in this page
+# echo $((-1 << 12)) > param2 # Mask 0xfffffffffffff000 - anywhere in this page
# echo 0x8 > error_type # Choose correctable memory error
# echo 1 > error_inject # Inject now
+You should see something like this in dmesg:
+
+[22715.830801] EDAC sbridge MC3: HANDLING MCE MEMORY ERROR
+[22715.834759] EDAC sbridge MC3: CPU 0: Machine Check Event: 0 Bank 7: 8c00004000010090
+[22715.834759] EDAC sbridge MC3: TSC 0
+[22715.834759] EDAC sbridge MC3: ADDR 12345000 EDAC sbridge MC3: MISC 144780c86
+[22715.834759] EDAC sbridge MC3: PROCESSOR 0:306e7 TIME 1422553404 SOCKET 0 APIC 0
+[22716.616173] EDAC MC3: 1 CE memory read error on CPU_SrcID#0_Channel#0_DIMM#0 (channel:0 slot:0 page:0x12345 offset:0x0 grain:32 syndrome:0x0 - area:DRAM err_code:0001:0090 socket:0 channel_mask:1 rank:0)
For more information about EINJ, please refer to ACPI specification
version 4.0, section 17.5 and ACPI 5.0, section 18.6.
DECLARE_PER_CPU(mce_banks_t, mce_poll_banks);
enum mcp_flags {
- MCP_TIMESTAMP = (1 << 0), /* log time stamp */
- MCP_UC = (1 << 1), /* log uncorrected errors */
- MCP_DONTLOG = (1 << 2), /* only clear, don't log */
+ MCP_TIMESTAMP = BIT(0), /* log time stamp */
+ MCP_UC = BIT(1), /* log uncorrected errors */
+ MCP_DONTLOG = BIT(2), /* only clear, don't log */
};
-void machine_check_poll(enum mcp_flags flags, mce_banks_t *b);
+bool machine_check_poll(enum mcp_flags flags, mce_banks_t *b);
int mce_notify_irq(void);
};
#define ATTR_LEN 16
+#define INITIAL_CHECK_INTERVAL 5 * 60 /* 5 minutes */
/* One object for each MCE bank, shared by all CPUs */
struct mce_bank {
extern mce_banks_t mce_banks_ce_disabled;
#ifdef CONFIG_X86_MCE_INTEL
-unsigned long mce_intel_adjust_timer(unsigned long interval);
-void mce_intel_cmci_poll(void);
+unsigned long cmci_intel_adjust_timer(unsigned long interval);
+bool mce_intel_cmci_poll(void);
void mce_intel_hcpu_update(unsigned long cpu);
void cmci_disable_bank(int bank);
#else
-# define mce_intel_adjust_timer mce_adjust_timer_default
-static inline void mce_intel_cmci_poll(void) { }
+# define cmci_intel_adjust_timer mce_adjust_timer_default
+static inline bool mce_intel_cmci_poll(void) { return false; }
static inline void mce_intel_hcpu_update(unsigned long cpu) { }
static inline void cmci_disable_bank(int bank) { }
#endif
#define CREATE_TRACE_POINTS
#include <trace/events/mce.h>
-#define SPINUNIT 100 /* 100ns */
+#define SPINUNIT 100 /* 100ns */
DEFINE_PER_CPU(unsigned, mce_exception_count);
static DEFINE_PER_CPU(struct mce, mces_seen);
static int cpu_missing;
-/* CMCI storm detection filter */
-static DEFINE_PER_CPU(unsigned long, mce_polled_error);
-
/*
* MCA banks polled by the period polling timer for corrected events.
* With Intel CMCI, this only has MCA banks which do not support CMCI (if any).
* is already totally * confused. In this case it's likely it will
* not fully execute the machine check handler either.
*/
-void machine_check_poll(enum mcp_flags flags, mce_banks_t *b)
+bool machine_check_poll(enum mcp_flags flags, mce_banks_t *b)
{
+ bool error_logged = false;
struct mce m;
int severity;
int i;
if (!(m.status & MCI_STATUS_VAL))
continue;
- this_cpu_write(mce_polled_error, 1);
+
/*
* Uncorrected or signalled events are handled by the exception
* handler when it is enabled, so don't process those here.
* Don't get the IP here because it's unlikely to
* have anything to do with the actual error location.
*/
- if (!(flags & MCP_DONTLOG) && !mca_cfg.dont_log_ce)
+ if (!(flags & MCP_DONTLOG) && !mca_cfg.dont_log_ce) {
+ error_logged = true;
mce_log(&m);
+ }
/*
* Clear state for this bank.
*/
sync_core();
+
+ return error_logged;
}
EXPORT_SYMBOL_GPL(machine_check_poll);
* other CPUs.
*/
if (m && global_worst >= MCE_PANIC_SEVERITY && mca_cfg.tolerant < 3)
- mce_panic("Fatal Machine check", m, msg);
+ mce_panic("Fatal machine check", m, msg);
/*
* For UC somewhere we let the CPU who detects it handle it.
* source or one CPU is hung. Panic.
*/
if (global_worst <= MCE_KEEP_SEVERITY && mca_cfg.tolerant < 3)
- mce_panic("Machine check from unknown source", NULL, NULL);
+ mce_panic("Fatal machine check from unknown source", NULL, NULL);
/*
* Now clear all the mces_seen so that they don't reappear on
* poller finds an MCE, poll 2x faster. When the poller finds no more
* errors, poll 2x slower (up to check_interval seconds).
*/
-static unsigned long check_interval = 5 * 60; /* 5 minutes */
+static unsigned long check_interval = INITIAL_CHECK_INTERVAL;
static DEFINE_PER_CPU(unsigned long, mce_next_interval); /* in jiffies */
static DEFINE_PER_CPU(struct timer_list, mce_timer);
return interval;
}
-static unsigned long (*mce_adjust_timer)(unsigned long interval) =
- mce_adjust_timer_default;
+static unsigned long (*mce_adjust_timer)(unsigned long interval) = mce_adjust_timer_default;
-static int cmc_error_seen(void)
+static void __restart_timer(struct timer_list *t, unsigned long interval)
{
- unsigned long *v = this_cpu_ptr(&mce_polled_error);
+ unsigned long when = jiffies + interval;
+ unsigned long flags;
+
+ local_irq_save(flags);
+
+ if (timer_pending(t)) {
+ if (time_before(when, t->expires))
+ mod_timer_pinned(t, when);
+ } else {
+ t->expires = round_jiffies(when);
+ add_timer_on(t, smp_processor_id());
+ }
- return test_and_clear_bit(0, v);
+ local_irq_restore(flags);
}
static void mce_timer_fn(unsigned long data)
{
struct timer_list *t = this_cpu_ptr(&mce_timer);
+ int cpu = smp_processor_id();
unsigned long iv;
- int notify;
- WARN_ON(smp_processor_id() != data);
+ WARN_ON(cpu != data);
+
+ iv = __this_cpu_read(mce_next_interval);
if (mce_available(this_cpu_ptr(&cpu_info))) {
- machine_check_poll(MCP_TIMESTAMP,
- this_cpu_ptr(&mce_poll_banks));
- mce_intel_cmci_poll();
+ machine_check_poll(MCP_TIMESTAMP, this_cpu_ptr(&mce_poll_banks));
+
+ if (mce_intel_cmci_poll()) {
+ iv = mce_adjust_timer(iv);
+ goto done;
+ }
}
/*
- * Alert userspace if needed. If we logged an MCE, reduce the
- * polling interval, otherwise increase the polling interval.
+ * Alert userspace if needed. If we logged an MCE, reduce the polling
+ * interval, otherwise increase the polling interval.
*/
- iv = __this_cpu_read(mce_next_interval);
- notify = mce_notify_irq();
- notify |= cmc_error_seen();
- if (notify) {
+ if (mce_notify_irq())
iv = max(iv / 2, (unsigned long) HZ/100);
- } else {
+ else
iv = min(iv * 2, round_jiffies_relative(check_interval * HZ));
- iv = mce_adjust_timer(iv);
- }
+
+done:
__this_cpu_write(mce_next_interval, iv);
- /* Might have become 0 after CMCI storm subsided */
- if (iv) {
- t->expires = jiffies + iv;
- add_timer_on(t, smp_processor_id());
- }
+ __restart_timer(t, iv);
}
/*
void mce_timer_kick(unsigned long interval)
{
struct timer_list *t = this_cpu_ptr(&mce_timer);
- unsigned long when = jiffies + interval;
unsigned long iv = __this_cpu_read(mce_next_interval);
- if (timer_pending(t)) {
- if (time_before(when, t->expires))
- mod_timer_pinned(t, when);
- } else {
- t->expires = round_jiffies(when);
- add_timer_on(t, smp_processor_id());
- }
+ __restart_timer(t, interval);
+
if (interval < iv)
__this_cpu_write(mce_next_interval, interval);
}
switch (c->x86_vendor) {
case X86_VENDOR_INTEL:
mce_intel_feature_init(c);
- mce_adjust_timer = mce_intel_adjust_timer;
+ mce_adjust_timer = cmci_intel_adjust_timer;
break;
case X86_VENDOR_AMD:
mce_amd_feature_init(c);
return (bank == 4);
}
-static const char * const bank4_names(struct threshold_block *b)
+static const char *bank4_names(const struct threshold_block *b)
{
switch (b->address) {
/* MSR4_MISC0 */
if (!b.interrupt_capable)
goto init;
+ b.interrupt_enable = 1;
new = (high & MASK_LVTOFF_HI) >> 20;
offset = setup_APIC_mce(offset, new);
log:
mce_setup(&m);
rdmsrl(MSR_IA32_MCx_STATUS(bank), m.status);
+ if (!(m.status & MCI_STATUS_VAL))
+ return;
m.misc = ((u64)high << 32) | low;
m.bank = bank;
mce_log(&m);
b->interrupt_capable = lvt_interrupt_supported(bank, high);
b->threshold_limit = THRESHOLD_MAX;
- if (b->interrupt_capable)
+ if (b->interrupt_capable) {
threshold_ktype.default_attrs[2] = &interrupt_enable.attr;
- else
+ b->interrupt_enable = 1;
+ } else {
threshold_ktype.default_attrs[2] = NULL;
+ }
INIT_LIST_HEAD(&b->miscj);
*/
static DEFINE_PER_CPU(mce_banks_t, mce_banks_owned);
+/*
+ * CMCI storm detection backoff counter
+ *
+ * During storm, we reset this counter to INITIAL_CHECK_INTERVAL in case we've
+ * encountered an error. If not, we decrement it by one. We signal the end of
+ * the CMCI storm when it reaches 0.
+ */
+static DEFINE_PER_CPU(int, cmci_backoff_cnt);
+
/*
* cmci_discover_lock protects against parallel discovery attempts
* which could race against each other.
#define CMCI_THRESHOLD 1
#define CMCI_POLL_INTERVAL (30 * HZ)
-#define CMCI_STORM_INTERVAL (1 * HZ)
+#define CMCI_STORM_INTERVAL (HZ)
#define CMCI_STORM_THRESHOLD 15
static DEFINE_PER_CPU(unsigned long, cmci_time_stamp);
return !!(cap & MCG_CMCI_P);
}
-void mce_intel_cmci_poll(void)
+bool mce_intel_cmci_poll(void)
{
if (__this_cpu_read(cmci_storm_state) == CMCI_STORM_NONE)
- return;
- machine_check_poll(MCP_TIMESTAMP, this_cpu_ptr(&mce_banks_owned));
+ return false;
+
+ /*
+ * Reset the counter if we've logged an error in the last poll
+ * during the storm.
+ */
+ if (machine_check_poll(MCP_TIMESTAMP, this_cpu_ptr(&mce_banks_owned)))
+ this_cpu_write(cmci_backoff_cnt, INITIAL_CHECK_INTERVAL);
+ else
+ this_cpu_dec(cmci_backoff_cnt);
+
+ return true;
}
void mce_intel_hcpu_update(unsigned long cpu)
per_cpu(cmci_storm_state, cpu) = CMCI_STORM_NONE;
}
-unsigned long mce_intel_adjust_timer(unsigned long interval)
+unsigned long cmci_intel_adjust_timer(unsigned long interval)
{
- int r;
-
- if (interval < CMCI_POLL_INTERVAL)
- return interval;
+ if ((this_cpu_read(cmci_backoff_cnt) > 0) &&
+ (__this_cpu_read(cmci_storm_state) == CMCI_STORM_ACTIVE)) {
+ mce_notify_irq();
+ return CMCI_STORM_INTERVAL;
+ }
switch (__this_cpu_read(cmci_storm_state)) {
case CMCI_STORM_ACTIVE:
+
/*
* We switch back to interrupt mode once the poll timer has
- * silenced itself. That means no events recorded and the
- * timer interval is back to our poll interval.
+ * silenced itself. That means no events recorded and the timer
+ * interval is back to our poll interval.
*/
__this_cpu_write(cmci_storm_state, CMCI_STORM_SUBSIDED);
- r = atomic_sub_return(1, &cmci_storm_on_cpus);
- if (r == 0)
+ if (!atomic_sub_return(1, &cmci_storm_on_cpus))
pr_notice("CMCI storm subsided: switching to interrupt mode\n");
+
/* FALLTHROUGH */
case CMCI_STORM_SUBSIDED:
/*
- * We wait for all cpus to go back to SUBSIDED
- * state. When that happens we switch back to
- * interrupt mode.
+ * We wait for all CPUs to go back to SUBSIDED state. When that
+ * happens we switch back to interrupt mode.
*/
if (!atomic_read(&cmci_storm_on_cpus)) {
__this_cpu_write(cmci_storm_state, CMCI_STORM_NONE);
}
return CMCI_POLL_INTERVAL;
default:
- /*
- * We have shiny weather. Let the poll do whatever it
- * thinks.
- */
+
+ /* We have shiny weather. Let the poll do whatever it thinks. */
return interval;
}
}
cmci_storm_disable_banks();
__this_cpu_write(cmci_storm_state, CMCI_STORM_ACTIVE);
r = atomic_add_return(1, &cmci_storm_on_cpus);
- mce_timer_kick(CMCI_POLL_INTERVAL);
+ mce_timer_kick(CMCI_STORM_INTERVAL);
+ this_cpu_write(cmci_backoff_cnt, INITIAL_CHECK_INTERVAL);
if (r == 1)
pr_notice("CMCI storm detected: switching to poll mode\n");
{
if (cmci_storm_detect())
return;
+
machine_check_poll(MCP_TIMESTAMP, this_cpu_ptr(&mce_banks_owned));
mce_notify_irq();
}
if (!mce_available(raw_cpu_ptr(&cpu_info)) || !cmci_supported(&banks))
return;
+
local_irq_save(flags);
machine_check_poll(MCP_TIMESTAMP, this_cpu_ptr(&mce_banks_owned));
local_irq_restore(flags);
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