From 469fb2c3c1bbaa092f541e3a8d3b3554042aa6a5 Mon Sep 17 00:00:00 2001 From: Pu Lehui Date: Thu, 24 Aug 2023 09:49:55 +0000 Subject: [PATCH] riscv, bpf: Fix missing exception handling and redundant zext for LDX_B/H/W For LDX_B/H/W, when zext has been inserted by verifier, it'll return 1, and no exception handling will continue. Also, when the offset is 12-bit value, the redundant zext inserted by the verifier is not removed. Fix both scenarios by moving down the removal of redundant zext. Signed-off-by: Pu Lehui Link: https://lore.kernel.org/r/20230824095001.3408573-2-pulehui@huaweicloud.com Signed-off-by: Alexei Starovoitov --- arch/riscv/net/bpf_jit_comp64.c | 9 +++------ 1 file changed, 3 insertions(+), 6 deletions(-) diff --git a/arch/riscv/net/bpf_jit_comp64.c b/arch/riscv/net/bpf_jit_comp64.c index 0ca4f5c0097c..f2644e7ea6b5 100644 --- a/arch/riscv/net/bpf_jit_comp64.c +++ b/arch/riscv/net/bpf_jit_comp64.c @@ -1512,8 +1512,6 @@ out_be: insns_start = ctx->ninsns; emit(rv_lbu(rd, 0, RV_REG_T1), ctx); insn_len = ctx->ninsns - insns_start; - if (insn_is_zext(&insn[1])) - return 1; break; case BPF_H: if (is_12b_int(off)) { @@ -1528,8 +1526,6 @@ out_be: insns_start = ctx->ninsns; emit(rv_lhu(rd, 0, RV_REG_T1), ctx); insn_len = ctx->ninsns - insns_start; - if (insn_is_zext(&insn[1])) - return 1; break; case BPF_W: if (is_12b_int(off)) { @@ -1544,8 +1540,6 @@ out_be: insns_start = ctx->ninsns; emit(rv_lwu(rd, 0, RV_REG_T1), ctx); insn_len = ctx->ninsns - insns_start; - if (insn_is_zext(&insn[1])) - return 1; break; case BPF_DW: if (is_12b_int(off)) { @@ -1566,6 +1560,9 @@ out_be: ret = add_exception_handler(insn, ctx, rd, insn_len); if (ret) return ret; + + if (BPF_SIZE(code) != BPF_DW && insn_is_zext(&insn[1])) + return 1; break; } /* speculation barrier */