On Fri, Jan 24, 2025 at 09:59:37AM -0800, Andrii Nakryiko wrote: > On Tue, Jan 21, 2025 at 6:32 PM Josh Poimboeuf <[email protected]> wrote: > > > > Add optional support for user space frame pointer unwinding. If > > supported, the arch needs to enable CONFIG_HAVE_UNWIND_USER_FP and > > define ARCH_INIT_USER_FP_FRAME. > > > > By encoding the frame offsets in struct unwind_user_frame, much of this > > code can also be reused for future unwinder implementations like sframe. > > > > Signed-off-by: Josh Poimboeuf <[email protected]> > > --- > > arch/Kconfig | 4 +++ > > include/asm-generic/unwind_user.h | 9 ++++++ > > include/linux/unwind_user_types.h | 1 + > > kernel/unwind/user.c | 49 +++++++++++++++++++++++++++++-- > > 4 files changed, 60 insertions(+), 3 deletions(-) > > create mode 100644 include/asm-generic/unwind_user.h > > > > Do you plan to reuse this logic for stack unwinding done by perf > subsystem in perf_callchain_user()? See is_uprobe_at_func_entry() > parts and also fixup_uretprobe_trampoline_entries() for some of the > quirks that have to be taken into account when doing frame > pointer-based unwinding. It would be great not to lose those in this > new reimplementation. > > Not sure what's the best way to avoid duplicating the logic, but I > thought I'd bring that up.
Indeed! That was on the todo list and somehow evaporated. -- Josh
