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| author | Paul Chaignon <paul.chaignon@orange.com> | 2019-12-09 19:52:07 +0100 |
|---|---|---|
| committer | Daniel Borkmann <daniel@iogearbox.net> | 2019-12-11 13:57:17 +0100 |
| commit | 96bc4432f5ade1045521f3b247f516b1478166bd (patch) | |
| tree | fdfa20e990e22c74004d58a1246f958112394b86 /arch | |
| parent | 24dee0c7478d1a1e00abdf5625b7f921467325dc (diff) | |
| download | linux-96bc4432f5ade1045521f3b247f516b1478166bd.tar.gz linux-96bc4432f5ade1045521f3b247f516b1478166bd.tar.bz2 linux-96bc4432f5ade1045521f3b247f516b1478166bd.zip | |
bpf, riscv: Limit to 33 tail calls
All BPF JIT compilers except RISC-V's and MIPS' enforce a 33-tail calls
limit at runtime. In addition, a test was recently added, in tailcalls2,
to check this limit.
This patch updates the tail call limit in RISC-V's JIT compiler to allow
33 tail calls. I tested it using the above selftest on an emulated
RISCV64.
Fixes: 2353ecc6f91f ("bpf, riscv: add BPF JIT for RV64G")
Reported-by: Mahshid Khezri <khezri.mahshid@gmail.com>
Signed-off-by: Paul Chaignon <paul.chaignon@orange.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Björn Töpel <bjorn.topel@gmail.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/966fe384383bf23a0ee1efe8d7291c78a3fb832b.1575916815.git.paul.chaignon@gmail.com
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/riscv/net/bpf_jit_comp.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/riscv/net/bpf_jit_comp.c b/arch/riscv/net/bpf_jit_comp.c index 5451ef3845f2..7fbf56aab661 100644 --- a/arch/riscv/net/bpf_jit_comp.c +++ b/arch/riscv/net/bpf_jit_comp.c @@ -631,14 +631,14 @@ static int emit_bpf_tail_call(int insn, struct rv_jit_context *ctx) return -1; emit(rv_bgeu(RV_REG_A2, RV_REG_T1, off >> 1), ctx); - /* if (--TCC < 0) + /* if (TCC-- < 0) * goto out; */ emit(rv_addi(RV_REG_T1, tcc, -1), ctx); off = (tc_ninsn - (ctx->ninsns - start_insn)) << 2; if (is_13b_check(off, insn)) return -1; - emit(rv_blt(RV_REG_T1, RV_REG_ZERO, off >> 1), ctx); + emit(rv_blt(tcc, RV_REG_ZERO, off >> 1), ctx); /* prog = array->ptrs[index]; * if (!prog) |