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Test bpf_per_cpu_ptr() and bpf_this_cpu_ptr(). Test two paths in the kernel. If the base pointer points to a struct, the returned reg is of type PTR_TO_BTF_ID. Direct pointer dereference can be applied on the returned variable. If the base pointer isn't a struct, the returned reg is of type PTR_TO_MEM, which also supports direct pointer dereference. Signed-off-by: Hao Luo <haoluo@google.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Andrii Nakryiko <andriin@fb.com> Link: https://lore.kernel.org/bpf/20200929235049.2533242-7-haoluo@google.com
55 lines
1.4 KiB
C
55 lines
1.4 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2020 Google */
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#include "vmlinux.h"
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#include <bpf/bpf_helpers.h>
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__u64 out__runqueues_addr = -1;
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__u64 out__bpf_prog_active_addr = -1;
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__u32 out__rq_cpu = -1; /* percpu struct fields */
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int out__bpf_prog_active = -1; /* percpu int */
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__u32 out__this_rq_cpu = -1;
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int out__this_bpf_prog_active = -1;
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__u32 out__cpu_0_rq_cpu = -1; /* cpu_rq(0)->cpu */
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extern const struct rq runqueues __ksym; /* struct type global var. */
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extern const int bpf_prog_active __ksym; /* int type global var. */
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SEC("raw_tp/sys_enter")
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int handler(const void *ctx)
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{
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struct rq *rq;
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int *active;
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__u32 cpu;
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out__runqueues_addr = (__u64)&runqueues;
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out__bpf_prog_active_addr = (__u64)&bpf_prog_active;
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cpu = bpf_get_smp_processor_id();
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/* test bpf_per_cpu_ptr() */
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rq = (struct rq *)bpf_per_cpu_ptr(&runqueues, cpu);
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if (rq)
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out__rq_cpu = rq->cpu;
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active = (int *)bpf_per_cpu_ptr(&bpf_prog_active, cpu);
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if (active)
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out__bpf_prog_active = *active;
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rq = (struct rq *)bpf_per_cpu_ptr(&runqueues, 0);
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if (rq) /* should always be valid, but we can't spare the check. */
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out__cpu_0_rq_cpu = rq->cpu;
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/* test bpf_this_cpu_ptr */
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rq = (struct rq *)bpf_this_cpu_ptr(&runqueues);
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out__this_rq_cpu = rq->cpu;
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active = (int *)bpf_this_cpu_ptr(&bpf_prog_active);
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out__this_bpf_prog_active = *active;
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return 0;
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}
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char _license[] SEC("license") = "GPL";
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