Use TCO watchdog first timeout (pretimeout) to dump CPU backtraces and ease debug of watchdog expiration causes. TCO logic generates a SCI interrupt, then its handler dumps all CPU backtraces and calls panic (in order to execute registered panic callbacks). SCI interrupt number (GPE) is configured from ACPI tables.
Change-Id: If7badb962008ff38560a02575d0d41f6aaa5f7fd Signed-off-by: Francois-Nicolas Muller <[email protected]> --- drivers/watchdog/iTCO_wdt.c | 51 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c index cf8c50d..3dd4175 100644 --- a/drivers/watchdog/iTCO_wdt.c +++ b/drivers/watchdog/iTCO_wdt.c @@ -67,6 +67,8 @@ #include <linux/io.h> /* For inb/outb/... */ #include <linux/mfd/core.h> #include <linux/mfd/lpc_ich.h> +#include <linux/nmi.h> +#include <linux/acpi.h> #include "iTCO_vendor.h" @@ -124,6 +126,13 @@ module_param(turn_SMI_watchdog_clear_off, int, 0); MODULE_PARM_DESC(turn_SMI_watchdog_clear_off, "Turn off SMI clearing watchdog (depends on TCO-version)(default=1)"); +#define DEFAULT_PRETIMEOUT 0 +static bool pretimeout = DEFAULT_PRETIMEOUT; +module_param(pretimeout, bool, 0); +MODULE_PARM_DESC(pretimeout, + "Enable watchdog pretimeout (default=" + __MODULE_STRING(DEFAULT_PRETIMEOUT) ")"); + static int iTCO_wdt_active = 0; /* @@ -200,6 +209,45 @@ static int iTCO_wdt_unset_NO_REBOOT_bit(void) return ret; /* returns: 0 = OK, -EIO = Error */ } +static unsigned char *tco_hid = "8086229C"; + +static u32 iTCO_wdt_pretimeout_handler(acpi_handle gpe_device, u32 gpe, + void *context) +{ + /* dump backtraces for all available cores */ + trigger_all_cpu_backtrace(); + + /* call panic notifiers */ + panic("Kernel Watchdog"); + + return ACPI_INTERRUPT_HANDLED; +} + +static acpi_status __init iTCO_wdt_register_gpe(acpi_handle handle, + u32 lvl, void *context, void **rv) +{ + unsigned long long gpe; + acpi_status status; + union acpi_object object = { 0 }; + struct acpi_buffer buffer = { sizeof(union acpi_object), &object }; + + status = acpi_evaluate_object(handle, "_GPE", NULL, &buffer); + if (ACPI_FAILURE(status)) + return status; + + if (object.type != ACPI_TYPE_INTEGER) + return AE_BAD_DATA; + + gpe = object.integer.value; + status = acpi_install_gpe_handler(NULL, gpe, ACPI_GPE_EDGE_TRIGGERED, + iTCO_wdt_pretimeout_handler, NULL); + if (ACPI_FAILURE(status)) + return status; + + acpi_enable_gpe(NULL, gpe); + return AE_OK; +} + static int iTCO_wdt_start(struct watchdog_device *wd_dev) { unsigned int val; @@ -625,6 +673,9 @@ static int __init iTCO_wdt_init_module(void) if (err) return err; + if (pretimeout) + acpi_get_devices(tco_hid, iTCO_wdt_register_gpe, NULL, NULL); + return 0; } -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-watchdog" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
