Pu Lehui adebac5995 riscv, bpf: Emit fixed-length instructions for BPF_PSEUDO_FUNC
[ Upstream commit b54b6003612a376e7be32cbc5c1af3754bbbbb3d ]

For BPF_PSEUDO_FUNC instruction, verifier will refill imm with
correct addresses of bpf_calls and then run last pass of JIT.
Since the emit_imm of RV64 is variable-length, which will emit
appropriate length instructions accorroding to the imm, it may
broke ctx->offset, and lead to unpredictable problem, such as
inaccurate jump. So let's fix it with fixed-length instructions.

Fixes: 69c087ba6225 ("bpf: Add bpf_for_each_map_elem() helper")
Suggested-by: Björn Töpel <bjorn@rivosinc.com>
Signed-off-by: Pu Lehui <pulehui@huawei.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Björn Töpel <bjorn@kernel.org>
Acked-by: Björn Töpel <bjorn@kernel.org>
Link: https://lore.kernel.org/bpf/20221206091410.1584784-1-pulehui@huaweicloud.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-12-31 13:32:23 +01:00
..
2022-12-31 13:31:54 +01:00
2022-11-27 08:28:41 +09:00
2022-10-15 16:47:33 -07:00