From dc75a1ecbc2fcedc2facfa217421edeb5f2e1646 Mon Sep 17 00:00:00 2001 From: Hengqi Chen Date: Fri, 15 Dec 2023 14:21:38 +0000 Subject: [PATCH] LoongArch: BPF: Support 64-bit pointers to kfuncs Like commit 1cf3bfc60f9836f ("bpf: Support 64-bit pointers to kfuncs") for s390x, add support for 64-bit pointers to kfuncs for LoongArch. Since the infrastructure is already implemented in BPF core, the only thing need to be done is to override bpf_jit_supports_far_kfunc_call(). Before this change, several test_verifier tests failed: # ./test_verifier | grep # | grep FAIL #119/p calls: invalid kfunc call: ptr_to_mem to struct with non-scalar FAIL #120/p calls: invalid kfunc call: ptr_to_mem to struct with nesting depth > 4 FAIL #121/p calls: invalid kfunc call: ptr_to_mem to struct with FAM FAIL #122/p calls: invalid kfunc call: reg->type != PTR_TO_CTX FAIL #123/p calls: invalid kfunc call: void * not allowed in func proto without mem size arg FAIL #124/p calls: trigger reg2btf_ids[reg->type] for reg->type > __BPF_REG_TYPE_MAX FAIL #125/p calls: invalid kfunc call: reg->off must be zero when passed to release kfunc FAIL #126/p calls: invalid kfunc call: don't match first member type when passed to release kfunc FAIL #127/p calls: invalid kfunc call: PTR_TO_BTF_ID with negative offset FAIL #128/p calls: invalid kfunc call: PTR_TO_BTF_ID with variable offset FAIL #129/p calls: invalid kfunc call: referenced arg needs refcounted PTR_TO_BTF_ID FAIL #130/p calls: valid kfunc call: referenced arg needs refcounted PTR_TO_BTF_ID FAIL #486/p map_kptr: ref: reference state created and released on xchg FAIL This is because the kfuncs in the loaded module are far away from __bpf_call_base: ffff800002009440 t bpf_kfunc_call_test_fail1 [bpf_testmod] 9000000002e128d8 T __bpf_call_base The offset relative to __bpf_call_base does NOT fit in s32, which breaks the assumption in BPF core. Enable bpf_jit_supports_far_kfunc_call() lifts this limit. Note that to reproduce the above result, tools/testing/selftests/bpf/config should be applied, and run the test with JIT enabled, unpriv BPF enabled. With this change, the test_verifier tests now all passed: # ./test_verifier ... Summary: 777 PASSED, 0 SKIPPED, 0 FAILED Tested-by: Tiezhu Yang Signed-off-by: Hengqi Chen Signed-off-by: Huacai Chen --- arch/loongarch/net/bpf_jit.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/loongarch/net/bpf_jit.c b/arch/loongarch/net/bpf_jit.c index 4fcd6cd6da234d..2f154c60ee007a 100644 --- a/arch/loongarch/net/bpf_jit.c +++ b/arch/loongarch/net/bpf_jit.c @@ -201,6 +201,11 @@ bool bpf_jit_supports_kfunc_call(void) return true; } +bool bpf_jit_supports_far_kfunc_call(void) +{ + return true; +} + /* initialized on the first pass of build_body() */ static int out_offset = -1; static int emit_bpf_tail_call(struct jit_ctx *ctx)