10 System Reset Extension (EID #0x53525354 "SRST")
The System Reset Extension provides a function that allow the supervisor software to request system-level reboot or shutdown. The term "system" refers to the world-view of supervisor software and the underlying SBI implementation could be provided by machine mode firmware or a hypervisor.
10.1 Function: System reset (FID #0)
struct sbiret sbi_system_reset(uint32_t reset_type, uint32_t reset_reason)
Reset the system based on provided reset_type and reset_reason. This is
a synchronous call and does not return if it succeeds.
The reset_type parameter is 32 bits wide and it’s possible values are shown
in the Table 26 below.
Table 26. SRST System Reset Types
| Value | Description |
|---|---|
| 0x00000000 | Shutdown |
| 0x00000001 | Cold reboot |
| 0x00000002 | Warm reboot |
| 0x00000003 - 0xEFFFFFFF | Reserved for future use |
| 0xF0000000 - 0xFFFFFFFF | Vendor or platform specific reset type |
The reset_reason is an optional parameter representing the reason for
system reset. This parameter is 32 bits wide with possible values shown
in the Table 27 below
Table 27. SRST System Reset Reasons
| Value | Description |
|---|---|
| 0x00000000 | No reason |
| 0x00000001 | System failure |
| 0x00000002 - 0xDFFFFFFF | Reserved for future use |
| 0xE0000000 - 0xEFFFFFFF | SBI implementation specific reset reason |
| 0xF0000000 - 0xFFFFFFFF | Vendor or platform specific reset reason |
When supervisor software is running natively, the SBI implementation is provided by machine mode firmware. In this case, shutdown is equivalent to a physical power down of the entire system and cold reboot is equivalent to a physical power cycle of the entire system. Further, warm reboot is equivalent to a power cycle of the main processor and parts of the system, but not the entire system. For example, on a server class system with a BMC (board management controller), a warm reboot will not power cycle the BMC whereas a cold reboot will definitely power cycle the BMC.
When supervisor software is running inside a virtual machine, the SBI implementation is provided by a hypervisor. Shutdown, cold reboot and warm reboot will behave functionally the same as the native case, but might not result in any physical power changes.
The possible error codes returned in sbiret.error are shown in the
Table 28 below.
Table 28. SRST System Reset Errors
| Error code | Description |
|---|---|
| SBI_ERR_INVALID_PARAM | At least one of reset_type or reset_reason is reserved or is platform-specific and unimplemented. |
| SBI_ERR_NOT_SUPPORTED | reset_type is not reserved and is implemented, but the platform does not support it due to one or more missing dependencies. |
| SBI_ERR_FAILED | The reset request failed for unspecified or unknown other reasons. |
10.2 Function Listing
Table 29. SRST Function List
| Function Name | SBI Version | FID | EID |
|---|---|---|---|
| sbi_system_reset | 0.3 | 0 | 0x53525354 |