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OpenCloudOS-Kernel
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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 <pulehui@huawei.com>
Link: https://lore.kernel.org/r/20230824095001.3408573-2-pulehui@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Pu Lehui 2023-08-24 09:49:55 +00:00 committed by Alexei Starovoitov
parent 1b580c9bb6
commit 469fb2c3c1
1 changed files with 3 additions and 6 deletions
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9
arch/riscv/net/bpf_jit_comp64.c
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@ -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 */