On Thursday 13 November 2014 15:49:20 Ulrich Weigand wrote:
Arnd Bergmann arnd@arndb.de wrote on 13.11.2014 11:21:28:
I have to admit that I don't really understand gdb internals, but from a first look I get the impression that it will just do the right thing if you reuse NT_S390_SYSTEM_CALL on ARM64 with the same semantics.
There's an interface between BFD and GDB proper involved here. BFD will detect the presence of register set notes in the core dump, and will translate them into virtual sections; GDB will then simply look up such sections under well-known names.
In particular, the NT_S390_SYSTEM_CALL note will be translated by BFD into a virtual section named ".reg-s390-system-call"; GDB platform- specific code will look for sections of this particular name.
So if you were to create notes using the same note type, by default it would do nothing on ARM64. You might add code to the ARM64 back-end to also look for a section ".reg-s390-system-call", but that would be somewhat confusing. Using a new, platform-specific note type for ARM64 would appear to fit better with existing precedent.
Ok, thanks a lot for your insight and for confirming what Takahiro AKASHI said. Let's use a new NT_ARM64_SYSTEM_CALL type with a different number then.
Arnd