ca779acd72
The memory grant identifier for safecopies now includes a sequence number in its upper bits, to prevent accidental reuse of a grant ID after revocation and subsequent reallocation. This should increase overall system robustness by a tiny amount, and possibly help catch bugs in system services early on. For now, the lower 20 bits of the grant ID are used as grant table slot index (thus allowing for up to a million grants per process), and the next 11 bits of the (signed 32-bit) grant ID are used to store the per-slot sequence number. As grant IDs are never exposed to userland, the split can be changed later on without breaking the userland ABI. Change-Id: Ic34be27ff2a45db0ea5db037a24eef9efcd9ca40