Memory #
Memory capabilities represent a range of conventional physical memory available for the allocation of pages and kernel objects. The allocation of most other capabilities requires the use of a memory capability in order to store the state associated with its respective kernel object.
Only the following capabilities support allocation via this interface:
- CSpace
- Endpoint
- Notification
- Page
- Task
- VSpace
- PDPT, PD, PT (x86_64)
- L1PT, L2PT, L3PT (aarch64)
Operations #
Memory::ALLOCATE #
Allocates new kernel objects.
This operation is atomic; if insufficient memory is available then no objects will be allocated. However, the value of the out parameter in the caller’s IPC buffer is undefined in such cases.
Parameters #
The meaning of the size parameter, if provided, is specific to each capability type.
| Register | Details |
|---|---|
| r0 | Capability type |
| r1 | Size (optional) |
Capabilities #
| CSlot | Usage | Type | Details |
|---|---|---|---|
| … | Out | CAddr | Capability slots to store the new capabilities in |
Results #
| Error code | Meaning |
|---|---|
| NONE | Success |
| NOMEM | Insufficient memory to allocate objects |
| INVALID_PARAM | Invalid combination of capability type and size paramter |
| INVALID_PARAM | Attempted to allocate zero capabilities |
| INVALID_CTYPE | Attempted to allocate an invalid capability type |
| INVALID_CSLOT | Attempted to allocate a capability in a non-null cslot |
Semantics #
Memory::ALLOCATE #
The user may allocate new memory capabilities using a subset of the parent capability’s physical memory by providing r0 = ctype::MEMORY and setting r1 to the desired number of pages of memory to use for the new capability.
Destroy #
Destroying a memory capability will destroy all objects allocated from that capability.