From 1b4d60ec162f82ea29a2e7a907b5c6cc9f926321 Mon Sep 17 00:00:00 2001 From: Song Liu Date: Fri, 25 Sep 2020 13:54:29 -0700 Subject: [PATCH] bpf: Enable BPF_PROG_TEST_RUN for raw_tracepoint Add .test_run for raw_tracepoint. Also, introduce a new feature that runs the target program on a specific CPU. This is achieved by a new flag in bpf_attr.test, BPF_F_TEST_RUN_ON_CPU. When this flag is set, the program is triggered on cpu with id bpf_attr.test.cpu. This feature is needed for BPF programs that handle perf_event and other percpu resources, as the program can access these resource locally. Signed-off-by: Song Liu Signed-off-by: Daniel Borkmann Acked-by: John Fastabend Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20200925205432.1777-2-songliubraving@fb.com --- include/linux/bpf.h | 3 ++ include/uapi/linux/bpf.h | 7 ++++ kernel/bpf/syscall.c | 2 +- kernel/trace/bpf_trace.c | 1 + net/bpf/test_run.c | 91 ++++++++++++++++++++++++++++++++++++++++++ tools/include/uapi/linux/bpf.h | 7 ++++ 6 files changed, 110 insertions(+), 1 deletion(-) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 79902325bef8..db6dcdee7933 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1396,6 +1396,9 @@ int bpf_prog_test_run_tracing(struct bpf_prog *prog, int bpf_prog_test_run_flow_dissector(struct bpf_prog *prog, const union bpf_attr *kattr, union bpf_attr __user *uattr); +int bpf_prog_test_run_raw_tp(struct bpf_prog *prog, + const union bpf_attr *kattr, + union bpf_attr __user *uattr); bool btf_ctx_access(int off, int size, enum bpf_access_type type, const struct bpf_prog *prog, struct bpf_insn_access_aux *info); diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index 2d6519a2ed77..82522f05c021 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -424,6 +424,11 @@ enum { */ #define BPF_F_QUERY_EFFECTIVE (1U << 0) +/* Flags for BPF_PROG_TEST_RUN */ + +/* If set, run the test on the cpu specified by bpf_attr.test.cpu */ +#define BPF_F_TEST_RUN_ON_CPU (1U << 0) + /* type for BPF_ENABLE_STATS */ enum bpf_stats_type { /* enabled run_time_ns and run_cnt */ @@ -566,6 +571,8 @@ union bpf_attr { */ __aligned_u64 ctx_in; __aligned_u64 ctx_out; + __u32 flags; + __u32 cpu; } test; struct { /* anonymous struct used by BPF_*_GET_*_ID */ diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index 2740df19f55e..3bc2ed2e171b 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -2979,7 +2979,7 @@ static int bpf_prog_query(const union bpf_attr *attr, } } -#define BPF_PROG_TEST_RUN_LAST_FIELD test.ctx_out +#define BPF_PROG_TEST_RUN_LAST_FIELD test.cpu static int bpf_prog_test_run(const union bpf_attr *attr, union bpf_attr __user *uattr) diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 36508f46a8db..2834866d379a 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -1678,6 +1678,7 @@ const struct bpf_verifier_ops raw_tracepoint_verifier_ops = { }; const struct bpf_prog_ops raw_tracepoint_prog_ops = { + .test_run = bpf_prog_test_run_raw_tp, }; const struct bpf_verifier_ops tracing_verifier_ops = { diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c index a66f211726e7..fde5db93507c 100644 --- a/net/bpf/test_run.c +++ b/net/bpf/test_run.c @@ -11,6 +11,7 @@ #include #include #include +#include #define CREATE_TRACE_POINTS #include @@ -204,6 +205,9 @@ int bpf_prog_test_run_tracing(struct bpf_prog *prog, int b = 2, err = -EFAULT; u32 retval = 0; + if (kattr->test.flags || kattr->test.cpu) + return -EINVAL; + switch (prog->expected_attach_type) { case BPF_TRACE_FENTRY: case BPF_TRACE_FEXIT: @@ -236,6 +240,87 @@ out: return err; } +struct bpf_raw_tp_test_run_info { + struct bpf_prog *prog; + void *ctx; + u32 retval; +}; + +static void +__bpf_prog_test_run_raw_tp(void *data) +{ + struct bpf_raw_tp_test_run_info *info = data; + + rcu_read_lock(); + migrate_disable(); + info->retval = BPF_PROG_RUN(info->prog, info->ctx); + migrate_enable(); + rcu_read_unlock(); +} + +int bpf_prog_test_run_raw_tp(struct bpf_prog *prog, + const union bpf_attr *kattr, + union bpf_attr __user *uattr) +{ + void __user *ctx_in = u64_to_user_ptr(kattr->test.ctx_in); + __u32 ctx_size_in = kattr->test.ctx_size_in; + struct bpf_raw_tp_test_run_info info; + int cpu = kattr->test.cpu, err = 0; + + /* doesn't support data_in/out, ctx_out, duration, or repeat */ + if (kattr->test.data_in || kattr->test.data_out || + kattr->test.ctx_out || kattr->test.duration || + kattr->test.repeat) + return -EINVAL; + + if (ctx_size_in < prog->aux->max_ctx_offset) + return -EINVAL; + + if ((kattr->test.flags & BPF_F_TEST_RUN_ON_CPU) == 0 && cpu != 0) + return -EINVAL; + + if (ctx_size_in) { + info.ctx = kzalloc(ctx_size_in, GFP_USER); + if (!info.ctx) + return -ENOMEM; + if (copy_from_user(info.ctx, ctx_in, ctx_size_in)) { + err = -EFAULT; + goto out; + } + } else { + info.ctx = NULL; + } + + info.prog = prog; + + if ((kattr->test.flags & BPF_F_TEST_RUN_ON_CPU) == 0 || + cpu == smp_processor_id()) { + __bpf_prog_test_run_raw_tp(&info); + } else { + /* smp_call_function_single() also checks cpu_online() + * after csd_lock(). However, since cpu is from user + * space, let's do an extra quick check to filter out + * invalid value before smp_call_function_single(). + */ + if (cpu >= nr_cpu_ids || !cpu_online(cpu)) { + err = -ENXIO; + goto out; + } + + err = smp_call_function_single(cpu, __bpf_prog_test_run_raw_tp, + &info, 1); + if (err) + goto out; + } + + if (copy_to_user(&uattr->test.retval, &info.retval, sizeof(u32))) + err = -EFAULT; + +out: + kfree(info.ctx); + return err; +} + static void *bpf_ctx_init(const union bpf_attr *kattr, u32 max_size) { void __user *data_in = u64_to_user_ptr(kattr->test.ctx_in); @@ -410,6 +495,9 @@ int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr, void *data; int ret; + if (kattr->test.flags || kattr->test.cpu) + return -EINVAL; + data = bpf_test_init(kattr, size, NET_SKB_PAD + NET_IP_ALIGN, SKB_DATA_ALIGN(sizeof(struct skb_shared_info))); if (IS_ERR(data)) @@ -607,6 +695,9 @@ int bpf_prog_test_run_flow_dissector(struct bpf_prog *prog, if (prog->type != BPF_PROG_TYPE_FLOW_DISSECTOR) return -EINVAL; + if (kattr->test.flags || kattr->test.cpu) + return -EINVAL; + if (size < ETH_HLEN) return -EINVAL; diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 2d6519a2ed77..82522f05c021 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -424,6 +424,11 @@ enum { */ #define BPF_F_QUERY_EFFECTIVE (1U << 0) +/* Flags for BPF_PROG_TEST_RUN */ + +/* If set, run the test on the cpu specified by bpf_attr.test.cpu */ +#define BPF_F_TEST_RUN_ON_CPU (1U << 0) + /* type for BPF_ENABLE_STATS */ enum bpf_stats_type { /* enabled run_time_ns and run_cnt */ @@ -566,6 +571,8 @@ union bpf_attr { */ __aligned_u64 ctx_in; __aligned_u64 ctx_out; + __u32 flags; + __u32 cpu; } test; struct { /* anonymous struct used by BPF_*_GET_*_ID */ -- 2.11.0