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/* Copyright 2022 The ChromiumOS Authors
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "common.h"
#include "console.h"
#include "cpu.h"
#include "ec_commands.h"
#include "hooks.h"
#include "host_command.h"
#include "panic.h"
#include "stddef.h"
#include "system.h"
#include "system_safe_mode.h"
#include "task.h"
#include "timer.h"
#include "watchdog.h"
#define STACK_PRINT_SIZE_WORDS 32
static bool in_safe_mode;
static const int safe_mode_allowed_hostcmds[] = {
EC_CMD_CONSOLE_READ,
EC_CMD_CONSOLE_SNAPSHOT,
EC_CMD_GET_NEXT_EVENT,
EC_CMD_GET_PANIC_INFO,
EC_CMD_GET_PROTOCOL_INFO,
EC_CMD_GET_UPTIME_INFO,
EC_CMD_GET_VERSION,
EC_CMD_MEMORY_DUMP_GET_ENTRY_INFO,
EC_CMD_MEMORY_DUMP_GET_METADATA,
EC_CMD_MEMORY_DUMP_READ_MEMORY,
EC_CMD_SYSINFO,
};
bool is_task_safe_mode_critical(task_id_t task_id)
{
const task_id_t safe_mode_critical_tasks[] = {
#ifdef HAS_TASK_HOOKS
TASK_ID_HOOKS,
#endif
TASK_ID_IDLE,
#ifdef HAS_TASK_HOSTCMD
TASK_ID_HOSTCMD,
#endif
#ifdef HAS_TASK_MAIN
TASK_ID_MAIN,
#endif
#ifdef HAS_TASK_SYSWORKQ
TASK_ID_SYSWORKQ,
#endif
};
for (int i = 0; i < ARRAY_SIZE(safe_mode_critical_tasks); i++)
if (safe_mode_critical_tasks[i] == task_id)
return true;
return false;
}
bool is_current_task_safe_mode_critical(void)
{
return is_task_safe_mode_critical(task_get_current());
}
#ifndef CONFIG_ZEPHYR
int disable_non_safe_mode_critical_tasks(void)
{
for (task_id_t task_id = 0; task_id < TASK_ID_COUNT; task_id++) {
if (!is_task_safe_mode_critical(task_id)) {
task_disable_task(task_id);
}
}
return EC_SUCCESS;
}
#endif /* CONFIG_ZEPHYR */
void handle_system_safe_mode_timeout(void)
{
panic_printf("Safe mode timeout after %d msec\n",
CONFIG_SYSTEM_SAFE_MODE_TIMEOUT_MSEC);
panic_reboot();
}
DECLARE_DEFERRED(handle_system_safe_mode_timeout);
__overridable int schedule_system_safe_mode_timeout(void)
{
hook_call_deferred(&handle_system_safe_mode_timeout_data,
CONFIG_SYSTEM_SAFE_MODE_TIMEOUT_MSEC * MSEC);
return EC_SUCCESS;
}
bool system_is_in_safe_mode(void)
{
return !!in_safe_mode;
}
/*
* Print contents of stack to console buffer.
*/
static void print_panic_stack(void)
{
uint32_t sp;
const struct panic_data *pdata = panic_get_data();
ccprintf("\n========== Stack Contents ===========");
sp = get_panic_stack_pointer(pdata);
for (int i = 0; i < STACK_PRINT_SIZE_WORDS; i++) {
if (sp == 0 ||
sp + sizeof(uint32_t) > CONFIG_RAM_BASE + CONFIG_RAM_SIZE) {
ccprintf("\nSP(%x) out of range", sp);
break;
}
if (i % 4 == 0)
ccprintf("\n%08x:", sp);
ccprintf(" %08x", *(uint32_t *)sp);
sp += sizeof(uint32_t);
}
ccprintf("\n");
/* Flush so dump isn't mixed with other output */
cflush();
}
bool command_is_allowed_in_safe_mode(int command)
{
for (int i = 0; i < ARRAY_SIZE(safe_mode_allowed_hostcmds); i++)
if (command == safe_mode_allowed_hostcmds[i])
return true;
return false;
}
static void system_safe_mode_start(void)
{
ccprintf("*** Post Panic System Safe Mode ***\n");
if (IS_ENABLED(CONFIG_SYSTEM_SAFE_MODE_PRINT_STACK))
print_panic_stack();
if (IS_ENABLED(CONFIG_HOSTCMD_EVENTS))
host_set_single_event(EC_HOST_EVENT_PANIC);
}
DECLARE_DEFERRED(system_safe_mode_start);
int start_system_safe_mode(void)
{
if (!system_is_in_rw()) {
panic_printf("Can only enter safe mode from RW image\n");
return EC_ERROR_INVAL;
}
if (system_is_in_safe_mode()) {
panic_printf("Already in system safe mode");
return EC_ERROR_INVAL;
}
if (is_current_task_safe_mode_critical()) {
/* TODO: Restart critical tasks */
panic_printf(
"Fault in critical task, cannot enter system safe mode\n");
return EC_ERROR_INVAL;
}
disable_non_safe_mode_critical_tasks();
schedule_system_safe_mode_timeout();
/*
* Schedule a deferred function to run immediately
* after returning from fault handler. Defer operations that
* must not run in an ISR to this function.
*/
hook_call_deferred(&system_safe_mode_start_data, 0);
in_safe_mode = true;
panic_printf("\nStarting system safe mode\n");
return EC_SUCCESS;
}
#ifdef TEST_BUILD
void set_system_safe_mode(bool mode)
{
in_safe_mode = mode;
}
#endif
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