RChunk Class Reference

Creates a global, disconnected, chunk.

The chunk is global; i.e. it is visible to all processes and is intended for access by other user processes.

A disconnected chunk has a committed region consisting of an arbitrary set of MMU pages within the reserved region, i.e. each page-sized address range within the reserved region which begins on a page boundary may be committed independently.

aMaxSize specifies the maximum size of the chunk.

The difference between aInitialTop and aInitialBottom gives the number of bytes to be committed, on creation of the chunk; aInitialBottom gives the offset of the bottom of the committed region from the base of the chunk's reserved region; aInitialTop gives the offset of the top of the committed region from the base of the chunk's reserved region.

Both aInitialBottom and aInitialTop are rounded up to the next nearest processor page boundary value, if they are not already on a processor page boundary value.

The descriptor aName contains the name to be assigned to this global chunk.

By default, ownership of this chunk handle is vested in the current process. Ownership of the chunk handle can be vested in the current thread by passing EOwnerThread as the third parameter to this function.

Creates a local, disconnected chunk.

The chunk is local to the process creating it; i.e. it is private to the process creating it and is not intended for access by other user processes.

A disconnected chunk has a committed region consisting of an arbitrary set of MMU pages within the reserved region, i.e. each page-sized address range within the reserved region which begins on a page boundary may be committed independently.

aMaxSize specifies the maximum size of the chunk.

The difference between aInitialTop and aInitialBottom gives the number of bytes to be committed, on creation of the chunk; aInitialBottom gives the offset of the bottom of the committed region from the base of the chunk's reserved region; aInitialTop gives the offset of the top of the committed region from the base of the chunk's reserved region.

Both aInitialBottom and aInitialTop are rounded up to the next nearest processor page boundary value, if they are not already on a processor page boundary value.

By default, ownership of this chunk handle is vested in the current process. Ownership of the chunk handle can be vested in the current thread by passing EOwnerThread as the third parameter to this function.

Creates a global, double ended, chunk.

The chunk is global; i.e. it is visible to all processes and is intended for access by other user processes.

The committed region of a double ended chunk can be any contiguous subset of the reserved region.

aMaxSize specifies the maximum size of the chunk.

The difference between aInitialTop and aInitialBottom gives the number of bytes to be committed, on creation of the chunk; aInitialBottom gives the offset of the bottom of the committed region from the base of the chunk's reserved region; aInitialTop gives the offset of the top of the committed region from the base of the chunk's reserved region.

Both aInitialBottom and aInitialTop are rounded up to the next nearest processor page boundary value, if they are not already on a processor page boundary value.

The descriptor aName contains the name to be assigned to this global chunk.

By default, ownership of this chunk handle is vested in the current process. Ownership of the chunk handle can be vested in the current thread by passing EOwnerThread as the third parameter to this function.

Note that:

1. the lowest valid address in a double ended chunk is the sum of the base of the chunk's reserved region plus the adjusted value of aInitialBottom

2. the highest valid address in a double ended chunk is the the sum of the base of the chunk's reserved region plus the adjusted value of aInitialTop - 1.

Creates a local, double ended, chunk.

The chunk is local to the process creating it; i.e. it is private to the process creating it and is not intended for access by other user processes.

The committed region of a double ended chunk can be any contiguous subset of the reserved region.

aMaxSize specifies the maximum size of the chunk.

The difference between aInitialTop and aInitialBottom gives the number of bytes to be committed, on creation of the chunk; aInitialBottom gives the offset of the bottom of the committed region from the base of the chunk's reserved region; aInitialTop gives the offset of the top of the committed region from the base of the chunk's reserved region.

Both aInitialBottom and aInitialTop are rounded up to the next nearest processor page boundary value, if they are not already on a processor page boundary value.

By default, ownership of this chunk handle is vested in the current process. Ownership of the chunk handle can be vested in the current thread by passing EOwnerThread as the third parameter to this function.

Note that:

1. the lowest valid address in a double ended chunk is the sum of the base of the chunk's reserved region plus the adjusted value of aInitialBottom

2. the highest valid address in a double ended chunk is the the sum of the base of the chunk's reserved region plus the adjusted value of aInitialTop - 1.

Creates a global chunk.

The chunk is global; i.e. it is potentially visible to all processes and is intended for access by other user processes.

aMaxSize specifies the maximum size of the chunk and aSize specifies the number of bytes to be committed on creation of the chunk. Both values are rounded up to the next nearest processor page boundary value ,if they are not already on a processor page boundary value.

The committed region always starts at the bottom of the reserved region.

The descriptor aName contains the name to be assigned to this global chunk. If this name is empty, the chunk will be anonymous. Anonymous chunks cannot be accessed by other processes unless the creator explicitly passes them a handle to the chunk - this can be used to transfer large amounts of data between processes in a secure fashion.

By default, ownership of this chunk handle is vested in the current process. Ownership of the chunk handle can be vested in the current thread by passing EOwnerThread as the third parameter to this function.

Creates a local chunk.

The chunk is local to the process creating it; i.e. it is private to the process creating it and is not intended for access by other user processes.

aMaxSize specifies the maximum size of the chunk and aSize specifies the number of bytes to be committed on creation of the chunk. Both values are rounded up to the next nearest processor page boundary value if they are not already on a processor page boundary.

The committed region always starts at the bottom of the reserved region.

By default, ownership of this chunk handle is vested in the current process. Ownership of the chunk handle can be vested in the current thread by passing EOwnerThread as the third parameter to this function.

Creates a user writable chunk that is marked by the kernel as containing code.

The chunk is local to the process creating it, i.e. it is private to the process creating it and is not intended for access by other user processes.

On systems using a Harvard cache, this type of chunk removes the need to flush the instruction cache (I-Cache) on a context switch. However, the instruction Translation Look-aside Buffer (ITLB) still needs to be flushed when switching to or from a process with one of these chunks in its address space. Systems with a dynamic branch predictor may also need to flush their branch target buffer when switching from one process using this type of chunk to another.

See also: UserHeap::ChunkHeap User::IMB_Range

Decommits memory from a disconnected chunk.

TInt pageSize;
HAL::Get(HAL::EMemoryPageSize,pageSize)

This can be used to determine whether the data for the chunk is demand paged or not.

Tests whether the chunk is mapped into its process address space.

Tests whether the chunk mapped into its process address space and is writable.