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authorPaul Chaignon <paul.chaignon@orange.com>2019-12-09 19:52:07 +0100
committerDaniel Borkmann <daniel@iogearbox.net>2019-12-11 13:57:17 +0100
commit96bc4432f5ade1045521f3b247f516b1478166bd (patch)
treefdfa20e990e22c74004d58a1246f958112394b86 /arch
parent24dee0c7478d1a1e00abdf5625b7f921467325dc (diff)
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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.c4
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)