J7200 Host Descriptions¶
Introduction¶
This chapter provides information on the set of HostIDs permitted in this J7200 SoC. HostIDs uniquely identify each logically distinct high level software entity. A software entity identification number (HostID) can be assigned to an OS either native or virtualized, or a firmware/native application. The HostID is used to select the set of Secure Proxy channels for which this software entity should use to communicate with the System Firmware.
As an example with an R5 core, then there could be 0, 1, or n number of R5 related hosts. The only limit is the number of available Secure Proxy Channels. Typically though, an R5 core will be assigned one secure host as well as one non secure host, but may be assigned additional hosts for certain usecases. As for other cores, some will only use secure hosts, and others will only use non secure hosts. Since the hosts are tied to Secure Proxy Channels, hosts are just a way of sectioning off data for a designated purpose.
System Firmware also checks that the used HostID comes from software running on the correct core (as implied by Host Name in the below table) and with the correct security level (Security Status column).
Additionally, one of the key reasons why HostID is tied in with Secure Proxy channels is because it prevents spoofing. When a message is received by System Firmware, the Secure Proxy channel tied to the HostID in the message is verified against the Secure Proxy channel on which the message was received. Specifically, only the HostID listed in the “Host Name” column can use the Secure Proxy channel associated with it.
Enumeration of Host IDs¶
| Host ID | Host Name | Security Status | Description |
|---|---|---|---|
| 0 | DMSC | Secure | Security Controller |
| 3 | MCU_0_R5_0 | Non Secure | Cortex R5 context 0 on MCU island |
| 4 | MCU_0_R5_1 | Secure | Cortex R5 context 1 on MCU island(Boot) |
| 5 | MCU_0_R5_2 | Non Secure | Cortex R5 context 2 on MCU island |
| 6 | MCU_0_R5_3 | Secure | Cortex R5 context 3 on MCU island |
| 10 | A72_0 | Secure | Cortex A72 context 0 on Main island |
| 11 | A72_1 | Secure | Cortex A72 context 1 on Main island |
| 12 | A72_2 | Non Secure | Cortex A72 context 2 on Main island |
| 13 | A72_3 | Non Secure | Cortex A72 context 3 on Main island |
| 14 | A72_4 | Non Secure | Cortex A72 context 4 on Main island |
| 35 | MAIN_0_R5_0 | Non Secure | Cortex R5_0 context 0 on Main island |
| 36 | MAIN_0_R5_1 | Secure | Cortex R5_0 context 1 on Main island |
| 37 | MAIN_0_R5_2 | Non Secure | Cortex R5_0 context 2 on Main island |
| 38 | MAIN_0_R5_3 | Secure | Cortex R5_0 context 3 on Main island |
| 250 | DM2DMSC | Secure | DM to DMSC communication |
| 251 | DMSC2DM | Non Secure | DMSC to DM communication |
| 254 | DM | Non Secure | Device Management |
Note
- Description provides an intended purpose of the host ID, though on some systems, this might be used differently, backing memory and link allocations are made with the specified purpose in mind
- Security Status provides an intended purpose for the Host context