Hi Xu, On Thu Apr 24, 2025 at 2:00 PM CEST, Xu Kuohai wrote: > On 4/24/2025 3:24 AM, Alexis Lothoré wrote: >> Hi Andrii, >> >> On Wed Apr 23, 2025 at 7:15 PM CEST, Andrii Nakryiko wrote: >>> On Thu, Apr 17, 2025 at 12:14 AM Alexis Lothoré >>> <alexis.loth...@bootlin.com> wrote: >>>> >>>> Hi Andrii, >>>> >>>> On Wed Apr 16, 2025 at 11:24 PM CEST, Andrii Nakryiko wrote: >>>>> On Fri, Apr 11, 2025 at 1:32 PM Alexis Lothoré (eBPF Foundation) >>>>> <alexis.loth...@bootlin.com> wrote:
[...] >> Thanks for the pointer, I'll take a look at it. The more we discuss this >> series, the less member size sounds relevant for what I'm trying to achieve >> here. >> >> Following Xu's comments, I have been thinking about how I could detect the >> custom alignments and packing on structures, and I was wondering if I could >> somehow benefit from __attribute__ encoding in BTF info ([1]). But >> following your hint, I also see some btf_is_struct_packed() in >> tools/lib/bpf/btf_dump.c that could help. I'll dig this further and see if >> I can manage to make something work with all of this. >> > > With DWARF info, we might not need to detect the structure alignment anymore, > since the DW_AT_location attribute tells us where the structure parameter is > located on the stack, and DW_AT_byte_size gives us the size of the structure. I am not sure to follow you here, because DWARF info is not accessible from kernel at runtime, right ? Or are you meaning that we could, at build time, enrich the BTF info embedded in the kernel thanks to DWARF info ? Thanks, Alexis -- Alexis Lothoré, Bootlin Embedded Linux and Kernel engineering https://bootlin.com
