Struct TORRegionSpec

pub struct TORRegionSpec { /* private fields */ }

A RISC-V PMP memory region specification, configured in TOR mode.

This type checks that the supplied start and end addresses meet the RISC-V TOR requirements, namely that

• the region’s start address is aligned to a 4-byte boundary
• the region’s end address is aligned to a 4-byte boundary
• the region is at least 4 bytes long

Finally, RISC-V restricts physical address spaces to 34 bit on RV32, and 56 bit on RV64 platforms. A TORRegionSpec must not cover addresses exceeding this address space, respectively. In practice, this means that on RV64 platforms TORRegionSpecs whose encoded pmpaddrX CSR contains any non-zero bits in the 10 most significant bits will be rejected. In particular, with the end pmpaddrX CSR / address being exclusive, the region cannot span the last 4 bytes of the 56-bit address space on RV64, or the last 4 bytes of the 34-bit address space on RV32.

By accepting this type, PMP implementations can rely on these requirements to be verified.

Implementations

impl TORRegionSpec

pub fn from_pmpaddr_csrs( pmpaddr_a: usize, pmpaddr_b: usize, ) -> Option<TORRegionSpec>

Construct a new TORRegionSpec from a pair of pmpaddrX CSR values.

This method accepts two pmpaddrX CSR values that together are configured to describe a single TOR memory region. The second pmpaddr_b must be strictly greater than pmpaddr_a, which translates into a minimum region size of 4 bytes. Otherwise this function returns None.

For RV64 platforms, this operation also checks if the range would include any address outside of the 56 bit physical address space and, in this case, returns None (tests whether any of the 10 most significant bits of either pmpaddr are non-zero).

pub fn from_start_end(start: *const u8, end: *const u8) -> Option<Self>

Construct a new TORRegionSpec from a range of addresses.

This method accepts a start and end address. It returns Some(region) when all constraints specified in the TORRegionSpec’s documentation are satisfied, otherwise None.

pub fn pmpaddr_a(&self) -> usize

Get the first pmpaddrX CSR value that this TORRegionSpec encodes.

pub fn pmpaddr_b(&self) -> usize

Trait Implementations

impl Clone for TORRegionSpec

fn clone(&self) -> TORRegionSpec

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for TORRegionSpec

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Copy for TORRegionSpec