remove KMDB branch debugging support
KMDB has vestigial support for two features, ::step branch and ::branches. The former allows you to step to the next branch point, while the latter reports the "last few" branches, as recorded in MSRs such as the LBR.
However, this was never properly implemented for 64-bit, thus is effectively non-existent on any reasonably modern system. While it could be resurrected, fixing this would complicate KPTI implementation. As it's already broken, it's hard to argue that it will be missed; we'll just remove all the relevant code.
Updated by Electric Monk over 5 years ago
- Status changed from New to Closed
- % Done changed from 0 to 100
commit 399ca3a7ff315244c51a7bbd1d3ce2709ef6c7c6 Author: John Levon <email@example.com> Date: 2018-04-10T14:36:44.000Z 9210 remove KMDB branch debugging support 9211 ::crregs could do with cr2/cr3 support 9209 ::ttrace should be able to filter by thread Reviewed by: Patrick Mooney <firstname.lastname@example.org> Reviewed by: Yuri Pankov <email@example.com> Approved by: Gordon Ross <firstname.lastname@example.org>