| Message ID | 20240822084112.3257995-1-eddyz87@gmail.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | support bpf_fastcall patterns for calls to kfuncs | expand |
Hello: This series was applied to bpf/bpf-next.git (master) by Alexei Starovoitov <ast@kernel.org>: On Thu, 22 Aug 2024 01:41:06 -0700 you wrote: > As an extension of [1], allow bpf_fastcall patterns for kfuncs: > - pattern rules are the same as for helpers; > - spill/fill removal is allowed only for kfuncs listed in the > is_fastcall_kfunc_call (under assumption that such kfuncs would > always be members of special_kfunc_list). > > Allow bpf_fastcall rewrite for bpf_cast_to_kern_ctx() and > bpf_rdonly_cast() in order to conjure selftests for this feature. > > [...] Here is the summary with links: - [bpf-next,v3,1/6] bpf: rename nocsr -> bpf_fastcall in verifier https://git.kernel.org/bpf/bpf-next/c/ae010757a55b - [bpf-next,v3,2/6] selftests/bpf: rename nocsr -> bpf_fastcall in selftests https://git.kernel.org/bpf/bpf-next/c/adec67d372fe - [bpf-next,v3,3/6] bpf: support bpf_fastcall patterns for kfuncs https://git.kernel.org/bpf/bpf-next/c/b2ee6d27e9c6 - [bpf-next,v3,4/6] bpf: allow bpf_fastcall for bpf_cast_to_kern_ctx and bpf_rdonly_cast https://git.kernel.org/bpf/bpf-next/c/40609093247b - [bpf-next,v3,5/6] selftests/bpf: by default use arch mask allowing all archs https://git.kernel.org/bpf/bpf-next/c/f406026fefa7 - [bpf-next,v3,6/6] selftests/bpf: check if bpf_fastcall is recognized for kfuncs https://git.kernel.org/bpf/bpf-next/c/8c2e043daada You are awesome, thank you!
As an extension of [1], allow bpf_fastcall patterns for kfuncs: - pattern rules are the same as for helpers; - spill/fill removal is allowed only for kfuncs listed in the is_fastcall_kfunc_call (under assumption that such kfuncs would always be members of special_kfunc_list). Allow bpf_fastcall rewrite for bpf_cast_to_kern_ctx() and bpf_rdonly_cast() in order to conjure selftests for this feature. After this patch-set verifier would rewrite the program below: r2 = 1 *(u64 *)(r10 - 32) = r2 call %[bpf_cast_to_kern_ctx] r2 = *(u64 *)(r10 - 32) r0 = r2;" As follows: r2 = 1 /* spill/fill at r10[-32] is removed */ r0 = r1 /* replacement for bpf_cast_to_kern_ctx() */ r0 = r2 exit Also, attribute used by LLVM implementation of the feature had been changed from no_caller_saved_registers to bpf_fastcall (see [2]). This patch-set replaces references to nocsr by references to bpf_fastcall to keep LLVM and Kernel parts in sync. [1] no_caller_saved_registers attribute for helper calls https://lore.kernel.org/bpf/20240722233844.1406874-1-eddyz87@gmail.com/ [2] [BPF] introduce __attribute__((bpf_fastcall)) https://github.com/llvm/llvm-project/pull/105417 Changes v2->v3: - added a patch fixing arch_mask handling in test_loader, otherwise newly added tests for the feature were skipped (a fix for regression introduced by a recent commit); - fixed warning regarding unused 'params' variable; - applied stylistical fixes suggested by Yonghong; - added acks from Yonghong; Changes v1->v2: - added two patches replacing all mentions of nocsr by bpf_fastcall (suggested by Andrii); - removed KF_NOCSR flag (suggested by Yonghong). v1: https://lore.kernel.org/bpf/20240812234356.2089263-1-eddyz87@gmail.com/ v2: https://lore.kernel.org/bpf/20240817015140.1039351-1-eddyz87@gmail.com/ Eduard Zingerman (6): bpf: rename nocsr -> bpf_fastcall in verifier selftests/bpf: rename nocsr -> bpf_fastcall in selftests bpf: support bpf_fastcall patterns for kfuncs bpf: allow bpf_fastcall for bpf_cast_to_kern_ctx and bpf_rdonly_cast selftests/bpf: by default use arch mask allowing all archs selftests/bpf: check if bpf_fastcall is recognized for kfuncs include/linux/bpf.h | 6 +- include/linux/bpf_verifier.h | 18 +- kernel/bpf/helpers.c | 2 +- kernel/bpf/verifier.c | 181 +++++++++++------- .../selftests/bpf/prog_tests/verifier.c | 4 +- ...rifier_nocsr.c => verifier_bpf_fastcall.c} | 81 ++++++-- tools/testing/selftests/bpf/test_loader.c | 2 +- 7 files changed, 192 insertions(+), 102 deletions(-) rename tools/testing/selftests/bpf/progs/{verifier_nocsr.c => verifier_bpf_fastcall.c} (89%)