Re: [PATCH v3 3/3] LoongArch: BPF: Optimize 32-bit operations using native instructions

[Tiezhu Yang <yangtiezhu@loongson.cn>]

On 2026/10/16 下午11:18, Alexei Starovoitov wrote:
> On Fri, Oct 16, 2026 at 04:10 PM Tiezhu Yang <yangtiezhu@loongson.cn> wrote:
> 
>> All of the testcases of test_bpf passed on Loongson-3A6000 (with DIV32)
>> and Loongson-3A5000 (without DIV32), here are the test results:
> 
> fyi test_bpf is gone. See
> commit 4532e525b286 ("selftests/bpf: Remove the old test_bpf module").
> Pls run test_progs

I tested this series based on bpf-next tree with "./test_progs -a jit_insns"
and "./test_progs -a jit_insns_blinded", there are 3 pre-existing failures:
(1) #191/1   jit_insns/arena access with zero offset:FAIL
(2) #191/25  jit_insns/ldst_offsets:FAIL
(3) #192/11  jit_insns_blinded/ldst_offsets:FAIL

These 3 failures are entirely unrelated to this series; they still fail on
the clean, original bpf-next tree without this series.

The root cause is that LoongArch BPF JIT support for arena atomics and
sign-extending loads from arena is still a work-in-progress.

IIUC, there are already two patches to fix them, but need revisions:
https://lore.kernel.org/loongarch/20260702022322.51033-8-dongtai.guo@linux.dev/
https://lore.kernel.org/loongarch/20260702022322.51033-7-dongtai.guo@linux.dev/

Bypassing these known architectural gaps using the blacklist (-b) option
allows the remaining subtests under jit_insns and jit_insns_blinded to pass:

$ sudo ./test_progs -a jit_insns -b "jit_insns/arena access with zero 
offset,jit_insns/ldst_offsets"
#191/2   jit_insns/cast to a user address:OK
#191/3   jit_insns/alu_imm:OK
#191/4   jit_insns/alu_reg:OK
#191/5   jit_insns/alu_imm_regs:OK
#191/6   jit_insns/div_const:OK
#191/7   jit_insns/alu_reg_pairs:OK
#191/8   jit_insns/alu_edges:OK
#191/9   jit_insns/shifts:OK
#191/10  jit_insns/shift_counts:OK
#191/11  jit_insns/atomics:OK
#191/12  jit_insns/atomic_reg_pairs:OK
#191/13  jit_insns/xadd_chain:OK
#191/14  jit_insns/ld_imm64:OK
#191/15  jit_insns/jmp_imm:OK
#191/16  jit_insns/jmp_reg:OK
#191/17  jit_insns/jmp_reg_pairs:OK
#191/18  jit_insns/jmp_edges:OK
#191/19  jit_insns/staggered_jumps:OK
#191/20  jit_insns/max_jmp:OK
#191/21  jit_insns/convergence:OK
#191/22  jit_insns/calls:OK
#191/23  jit_insns/helper_calls:OK
#191/24  jit_insns/ldst_zero_off:OK
#191/26  jit_insns/acq_rel:OK
#191/27  jit_insns/movsx:OK
#191/28  jit_insns/jset_imm:OK
#191/29  jit_insns/cmp_imm:OK
#191/30  jit_insns/alu_consts:OK
#191/31  jit_insns/bswap:OK
#191/32  jit_insns/probe_mem:OK
#191     jit_insns:OK
Summary: 1/30 PASSED, 0 SKIPPED, 0/0 FAILED

$ sudo ./test_progs -a jit_insns_blinded -b jit_insns_blinded/ldst_offsets
#192/1   jit_insns_blinded/alu_imm:OK
#192/2   jit_insns_blinded/alu_imm_regs:OK
#192/3   jit_insns_blinded/alu_edges:OK
#192/4   jit_insns_blinded/div_const:OK
#192/5   jit_insns_blinded/shifts:OK
#192/6   jit_insns_blinded/xadd_chain:OK
#192/7   jit_insns_blinded/ld_imm64:OK
#192/8   jit_insns_blinded/jmp_imm:OK
#192/9   jit_insns_blinded/jmp_edges:OK
#192/10  jit_insns_blinded/ldst_zero_off:OK
#192/12  jit_insns_blinded/jset_imm:OK
#192/13  jit_insns_blinded/cmp_imm:OK
#192/14  jit_insns_blinded/alu_consts:OK
#192     jit_insns_blinded:OK
Summary: 1/13 PASSED, 0 SKIPPED, 0/0 FAILED

Thanks,
Tiezhu