On 7/22/25 2:13 PM, Steven Rostedt wrote:
On Tue, 22 Jul 2025 14:04:37 -0700
Indu Bhagat <indu.bha...@oracle.com> wrote:
Yes and No. The offset at which the text is loaded is _one_ part of the
information to "fill in the blanks". The other part is what to do with
that information (text_vma) or how to relocate the SFrame section itself
a.k.a. the relocation entries. To know the relocations, one will need
to get access to the respective relocation section, and hence access to
the ELF section headers.
You mean to find where in the sframe section itself that needs to be update?
Correct. Each relocation entry carries pieces of information like :what
is the location to update, how many bytes to update and what is the
calculation to use i.e., the relocation type.
OK, that makes sense. So sframes does need to still be in an ELF file for
its own relocations and such.
It will be interesting on how to do compression and on-demand page loading.
Right, its an open item.
Compression (SHF_COMPRESSED) for non SHF_ALLOC sections is doable. In
fact, debug sections use it already.
The tricky part is SHF_ALLOC and SHF_COMPRESSED, which is what SFrame
may need. This is currently not allowed in ELF. Some previous
discussion here https://groups.google.com/g/generic-abi/c/HUVhliUrTG0.
Not sure if things have evolved since.
There would need to be a table as well that will denote where in the
decompressed pages that relocations need to be performed.
-- Steve
