linux-kernel - [PATCH bpf-next v3 0/4] powerpc64/bpf: Add support for bpf arena and arena atomics

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Message-ID: <20250904100835.1100423-1-skb99@linux.ibm.com>
Date: Thu,  4 Sep 2025 15:38:31 +0530
From: Saket Kumar Bhaskar <skb99@...ux.ibm.com>
To: bpf@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        linux-kselftest@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: hbathini@...ux.ibm.com, sachinpb@...ux.ibm.com, venkat88@...ux.ibm.com,
        andrii@...nel.org, eddyz87@...il.com, mykolal@...com, ast@...nel.org,
        daniel@...earbox.net, martin.lau@...ux.dev, song@...nel.org,
        yonghong.song@...ux.dev, john.fastabend@...il.com, kpsingh@...nel.org,
        sdf@...ichev.me, haoluo@...gle.com, jolsa@...nel.org,
        christophe.leroy@...roup.eu, naveen@...nel.org, maddy@...ux.ibm.com,
        mpe@...erman.id.au, npiggin@...il.com, memxor@...il.com,
        iii@...ux.ibm.com, shuah@...nel.org
Subject: [PATCH bpf-next v3 0/4] powerpc64/bpf: Add support for bpf arena and arena atomics

This patch series introduces support for the PROBE_MEM32,
bpf_addr_space_cast and PROBE_ATOMIC instructions in the powerpc BPF JIT,
facilitating the implementation of BPF arena and arena atomics.

All selftests related to bpf_arena, bpf_arena_atomic(except
load_acquire/store_release) enablement are passing:

# ./test_progs -t arena_list
#5/1     arena_list/arena_list_1:OK
#5/2     arena_list/arena_list_1000:OK
#5       arena_list:OK
Summary: 1/2 PASSED, 0 SKIPPED, 0 FAILED

# ./test_progs -t arena_htab
#4/1     arena_htab/arena_htab_llvm:OK
#4/2     arena_htab/arena_htab_asm:OK
#4       arena_htab:OK
Summary: 1/2 PASSED, 0 SKIPPED, 0 FAILED

# ./test_progs -t verifier_arena
#464/1   verifier_arena/basic_alloc1:OK
#464/2   verifier_arena/basic_alloc2:OK
#464/3   verifier_arena/basic_alloc3:OK
#464/4   verifier_arena/iter_maps1:OK
#464/5   verifier_arena/iter_maps2:OK
#464/6   verifier_arena/iter_maps3:OK
#464     verifier_arena:OK
#465/1   verifier_arena_large/big_alloc1:OK
#465/2   verifier_arena_large/big_alloc2:OK
#465     verifier_arena_large:OK
Summary: 2/8 PASSED, 0 SKIPPED, 0 FAILED

# ./test_progs -t arena_atomics
#3/1     arena_atomics/add:OK
#3/2     arena_atomics/sub:OK
#3/3     arena_atomics/and:OK
#3/4     arena_atomics/or:OK
#3/5     arena_atomics/xor:OK
#3/6     arena_atomics/cmpxchg:OK
#3/7     arena_atomics/xchg:OK
#3/8     arena_atomics/uaf:OK
#3/9     arena_atomics/load_acquire:SKIP
#3/10    arena_atomics/store_release:SKIP
#3       arena_atomics:OK (SKIP: 2/10)
Summary: 1/8 PASSED, 2 SKIPPED, 0 FAILED

Changes since v2:
* Dropped arena_spin_lock selftest fix patch from the patchset as it has
  to go via bpf-next while these changes will go via powerpc tree.

v2:https://lore.kernel.org/all/20250829165135.1273071-1-skb99@linux.ibm.com/

Changes since v1:

Addressed comments from Chris:
* Squashed introduction of bpf_jit_emit_probe_mem_store() and its usage in
  one patch.
* Defined and used PPC_RAW_RLDICL_DOT to avoid the CMPDI.
* Removed conditional statement for fixup[0] = PPC_RAW_LI(dst_reg, 0);
* Indicated this change is limited to powerpc64 in subject.

Addressed comments from Alexei:
* Removed skel->rodata->nr_cpus = get_nprocs() and its usage to get
  currently online cpus(as it needs to be updated from userspace).

Addressed comments from Hari:
* Updated the bpf jit stack layout and associated macros to accommodate
  new NVR.

v1:https://lore.kernel.org/all/20250805062747.3479221-1-skb99@linux.ibm.com/

Saket Kumar Bhaskar (4):
  powerpc64/bpf: Implement PROBE_MEM32 pseudo instructions
  powerpc64/bpf: Implement bpf_addr_space_cast instruction
  powerpc64/bpf: Introduce bpf_jit_emit_atomic_ops() to emit atomic
    instructions
  powerpc64/bpf: Implement PROBE_ATOMIC instructions

 arch/powerpc/include/asm/ppc-opcode.h |   1 +
 arch/powerpc/net/bpf_jit.h            |   6 +-
 arch/powerpc/net/bpf_jit_comp.c       |  32 +-
 arch/powerpc/net/bpf_jit_comp32.c     |   2 +-
 arch/powerpc/net/bpf_jit_comp64.c     | 401 +++++++++++++++++++-------
 5 files changed, 330 insertions(+), 112 deletions(-)

-- 
2.43.5