Re: [RFC PATCH v3 00/11] powerpc: Add support for ftrace direct and BPF trampolines

Vishal Chourasia
2024-06-24T11:59:51Z

On Fri, Jun 21, 2024 at 12:24:03AM +0530, Naveen N Rao wrote:
> This is v3 of the patches posted here:
> http://lkml.kernel.org/r/cover.1718008093.git.naveen@kernel.org
>
> Since v2, I have addressed review comments from Steven and Masahiro
> along with a few fixes. Patches 7-11 are new in this series and add
> support for ftrace direct and bpf trampolines.
>
> This series depends on the patch series from Benjamin Gray adding
> support for patch_ulong():
> http://lkml.kernel.org/r/20240515024445.236364-1-bgray@linux.ibm.com

This patchset, along with its dependent patchset [2], enables support
for BPF schedulers introduced by the sched_ext patchset [1] on
Power Architecture.

Before this patchset, BPF schedulers were failing to load due to the
lack of trampoline support.

GitHub repo for sched_ext: https://github.com/sched-ext/sched_ext
Note: This repo has been archived. Please refer to the description
provided on the repo homepage for more details.

[1] v6 https://lore.kernel.org/lkml/20240501151312.635565-1-tj@kernel.org
[2] http://lkml.kernel.org/r/20240515024445.236364-1-bgray@linux.ibm.com

Thank you for the patch!
>
>
> - Naveen
>
>
> Naveen N Rao (11):
> powerpc/kprobes: Use ftrace to determine if a probe is at function
> entry
> powerpc/ftrace: Unify 32-bit and 64-bit ftrace entry code
> powerpc/module_64: Convert #ifdef to IS_ENABLED()
> powerpc/ftrace: Remove pointer to struct module from dyn_arch_ftrace
> kbuild: Add generic hook for architectures to use before the final
> vmlinux link
> powerpc64/ftrace: Move ftrace sequence out of line
> powerpc/ftrace: Add support for DYNAMIC_FTRACE_WITH_CALL_OPS
> powerpc/ftrace: Add support for DYNAMIC_FTRACE_WITH_DIRECT_CALLS
> samples/ftrace: Add support for ftrace direct samples on powerpc
> powerpc64/bpf: Fold bpf_jit_emit_func_call_hlp() into
> bpf_jit_emit_func_call_rel()
> powerpc64/bpf: Add support for bpf trampolines
>
> arch/Kconfig | 3 +
> arch/powerpc/Kconfig | 9 +
> arch/powerpc/Makefile | 8 +
> arch/powerpc/include/asm/ftrace.h | 29 +-
> arch/powerpc/include/asm/module.h | 5 +
> arch/powerpc/include/asm/ppc-opcode.h | 14 +
> arch/powerpc/kernel/asm-offsets.c | 11 +
> arch/powerpc/kernel/kprobes.c | 18 +-
> arch/powerpc/kernel/module_64.c | 67 +-
> arch/powerpc/kernel/trace/ftrace.c | 269 +++++++-
> arch/powerpc/kernel/trace/ftrace_64_pg.c | 73 +-
> arch/powerpc/kernel/trace/ftrace_entry.S | 210 ++++--
> arch/powerpc/kernel/vmlinux.lds.S | 3 +-
> arch/powerpc/net/bpf_jit.h | 11 +
> arch/powerpc/net/bpf_jit_comp.c | 702 +++++++++++++++++++-
> arch/powerpc/net/bpf_jit_comp32.c | 7 +-
> arch/powerpc/net/bpf_jit_comp64.c | 68 +-
> arch/powerpc/tools/Makefile | 10 +
> arch/powerpc/tools/gen-ftrace-pfe-stubs.sh | 49 ++
> samples/ftrace/ftrace-direct-modify.c | 85 ++-
> samples/ftrace/ftrace-direct-multi-modify.c | 101 ++-
> samples/ftrace/ftrace-direct-multi.c | 79 ++-
> samples/ftrace/ftrace-direct-too.c | 83 ++-
> samples/ftrace/ftrace-direct.c | 69 +-
> scripts/Makefile.vmlinux | 8 +
> scripts/link-vmlinux.sh | 11 +-
> 26 files changed, 1813 insertions(+), 189 deletions(-)
> create mode 100644 arch/powerpc/tools/Makefile
> create mode 100755 arch/powerpc/tools/gen-ftrace-pfe-stubs.sh
>
>
> base-commit: e2b06d707dd067509cdc9ceba783c06fa6a551c2
> prerequisite-patch-id: a1d50e589288239d5a8b1c1f354cd4737057c9d3
> prerequisite-patch-id: da4142d56880861bd0ad7ad7087c9e2670a2ee54
> prerequisite-patch-id: 609d292e054b2396b603890522a940fa0bdfb6d8
> prerequisite-patch-id: 6f7213fb77b1260defbf43be0e47bff9c80054cc
> prerequisite-patch-id: ad3b71bf071ae4ba1bee5b087e61a2055772a74f
> --
> 2.45.2
>