Re: [PATCH v4 17/39] unwind_user/sframe: Add support for reading .sframe headers
From: Jens Remus <hidden>
Date: 2025-02-05 13:57:32
Also in:
linux-perf-users, linux-toolchains, lkml
On 29.01.2025 03:02, Josh Poimboeuf wrote:
Note FDEs aren't even needed here as the unwinder doesn't need to know when a function begins/ends. The only info needed by the unwinder is just the fre_data struct. So a simple binary search of fres[] is all that's really needed.
In SFrame V2 FDEs specify ranges bound by function start address and length. FREs in contrast specify open ranges bounded by start address. Their effect ends either with the next FRE becoming into effect or when their FDE range ends. This concept enables holes in the .text section which do not have any valid FDE/FRE information associated. Your proposal lacks some sort of mechanism to replicate those holes. It could be FDEs with a flag (or no offsets?) that specifies their range has no valid information. Regards, Jens -- Jens Remus Linux on Z Development (D3303) +49-7031-16-1128 Office jremus@de.ibm.com IBM IBM Deutschland Research & Development GmbH; Vorsitzender des Aufsichtsrats: Wolfgang Wendt; Geschäftsführung: David Faller; Sitz der Gesellschaft: Böblingen; Registergericht: Amtsgericht Stuttgart, HRB 243294 IBM Data Privacy Statement: https://www.ibm.com/privacy/