diff options
| author | Varun R Mallya <varunrmallya@gmail.com> | 2026-06-03 02:28:47 +0530 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2026-06-05 15:26:18 -0700 |
| commit | 6d13ddb1d46525931d2324d9358721eb3c495d72 (patch) | |
| tree | 10d38a84624b2a60caa3d05cc9f32b41bc18428d /tools/testing/selftests/bpf | |
| parent | 557d0cc3f2520feba45360beeafb93203b3230e0 (diff) | |
bpf, riscv: inline bpf_get_current_task() and bpf_get_current_task_btf()
On RISC-V, the current task pointer is stored in the thread pointer
register (tp). Emit a single `mv a5, tp` instead of a full helper
call for BPF_FUNC_get_current_task and BPF_FUNC_get_current_task_btf.
Register bpf_jit_inlines_helper_call() entries for both helpers so the
verifier treats them as inlined, and add the expected `mv a5, tp`
annotation to the riscv64 selftests.
The following show changes before and after this patch.
Before patch:
auipc t1,0x817a # load upper PC-relative address
jalr -2004(t1) # call bpf_get_current_task helper
mv a5,a0 # move return value to BPF_REG_0
After patch:
mv a5,tp # directly: a5 = current (tp = thread pointer)
Benchmark (bpf_prog_test_run wrapping bpf_get_current_task in loop,
batch=100, 10s, QEMU RISC-V):
| runs/sec | helper-calls/sec | ns/call
-------------+-----------+------------------+---------
Before patch | 173,490 | 17,349,090 | 57
After patch | 320,497 | 32,049,780 | 31
-------------+-----------+------------------+---------
Improvement | +84.7% | +84.7% | -45.6%
Signed-off-by: Varun R Mallya <varunrmallya@gmail.com>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/r/20260602205847.102825-3-varunrmallya@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'tools/testing/selftests/bpf')
| -rw-r--r-- | tools/testing/selftests/bpf/progs/verifier_jit_inline.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/verifier_jit_inline.c b/tools/testing/selftests/bpf/progs/verifier_jit_inline.c index 885ff69a3a62..76d80605ec7f 100644 --- a/tools/testing/selftests/bpf/progs/verifier_jit_inline.c +++ b/tools/testing/selftests/bpf/progs/verifier_jit_inline.c @@ -10,6 +10,8 @@ __arch_x86_64 __jited(" addq %gs:{{.*}}, %rax") __arch_arm64 __jited(" mrs x8, SP_EL0") +__arch_riscv64 +__jited(" mv a5, tp") int inline_bpf_get_current_task(void) { bpf_get_current_task(); |