X-Git-Url: http://git.buserror.net/cgi-bin/gitweb.cgi?p=polintos%2Fscott%2Fpriv.git;a=blobdiff_plain;f=doc%2Forb%2Fparameter-info-block;h=b868a4474a0a7dcc6070fb7d6f9751716d6d3d38;hp=eeeb80095e0b3a6447861bbcc9b1254ee2d5653f;hb=bc696ad9b0d5a2ad04e2de5ad8b89f746dd78491;hpb=f343d0adfe9ab787cb65cd38e4c4c83aaeea76b7 diff --git a/doc/orb/parameter-info-block b/doc/orb/parameter-info-block index eeeb800..b868a44 100644 --- a/doc/orb/parameter-info-block +++ b/doc/orb/parameter-info-block @@ -1,32 +1,55 @@ -Parameter Info Block (PIB), all offsets in pointer-length words - Name Offset Meaning - buffer_size 0 Size of the destination buffer +Parameter Info Block (PIB) + Name Size Meaning + buffer_size 32-bit Size of the destination buffer, excluding + Copy segments. The total number of bytes in all of the segments that require a - buffer to be created in the destination address space. This is + buffer to be created in the destination address space, with each + buffer individually rounded up to an 8-byte alignment. This is specified so that the kernel can allocate one large buffer for all - segments before traversing the segment list. When returning from a - method, the buffer size only includes buffers allocated by the - caller; "inout" segments where the caller specified a non-NULL ptr, - and the callee did not increase the length, are not included + segments before traversing the segment list. When returning from + a method, the buffer size only includes buffers allocated by the + caller; "inout" segments where the caller specified a non-NULL + ptr, and the callee did not increase the length, are not included (because the kernel does not need to allocate a caller-side buffer - for them). The kernel may throw an exception if the actual - size is greater than specified in this field. + for them). The kernel may throw an exception if the actual size + is greater than specified in this field. + + This only covers the "normal" segments which are mapped only + for the duration of the call. Copy segments are handled + separately. + + copy_size 32-bit Size of all Copy segments. + + This is like buffer_size, but for Copy segments. - objlist_ptr 1 Pointer to the object list - objlist_len 2 Length of the object list + objlist_ptr pointer Pointer to the object list + newobj_ptr pointer Pointer to the new object list. + objlist_len 32-bit Length of the object list, in IDs + newobj_len 32-bit Length of the new object list. The object list is a special segment that contains object IDs rather than arbitrary data. Each object ID will be translated into the destination ID-space, allocating new IDs when - necessary. + necessary. The IDs themselves are 32 bits each, unsigned, + regardless of the pointer size. The first object in the list + is the object to receive the message. + + Objects which live in this address space have the high bit + clear; remote objects have the high bit set. When sending + an object reference that has not been exposed to the kernel + before, its interface hash should exist in the newobj list. + + + + num_segments 32-bit Number of data segments - num_segments 3 Number of data segments - segment.ptr 4+n*4 Pointer to data segment - segment.len 5+n*4 Length of data segment in bytes - segment.flags 6+n*4 Attributes of data segment - reserved 7+n*4 Reserved for future use, and to - ensure power-of-two indexing + segment.ptr pointer Pointer to data segment + segment.len 32-bit Length of data segment in bytes + segment.flags 32-bit Attributes of data segment + reserved Reserved for future use, and for + power-of-two indexing -- pad to + 32 bytes. Each segment describes data being transmitted to and/or from the callee. For out segments, the caller may designate a buffer to hold @@ -40,14 +63,11 @@ Parameter Info Block (PIB), all offsets in pointer-length words Segment Flags (see doc/orb/memory-management for more details): In 0x01 Data is copied/mapped from caller to callee. Out 0x02 Data is copied/mapped from callee to caller. - Shared 0x04 A permanent shared mapping is created. - Push 0x08 The region is unmapped from the source and - transferred to the destination. - Inline 0x10 The callee cannot change the length of an - Out segment. Ignored for In segments. - Immutable 0x20 The segment is to be mapped read-only in - the destination. Ignored unless Shared is - set. - Copy 0x8000 The segment is permanently copied into the + The data is unmapped from the callee unless + Copy is set. + Inline 0x04 The callee cannot change the length of an + Out segment, and the caller must provide the + buffer. Ignored for In segments. + Copy 0x08 The segment is permanently copied into the destination address space, with read/write access.