31 lines
788 B
C
31 lines
788 B
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2024 Meta Platforms, Inc. and affiliates. */
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#include <vmlinux.h>
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#include <bpf/bpf_tracing.h>
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#include "bpf_misc.h"
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char _license[] SEC("license") = "GPL";
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int tid;
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int i;
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SEC("tp_btf/bpf_testmod_test_raw_tp_null")
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int BPF_PROG(test_raw_tp_null, struct sk_buff *skb)
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{
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struct task_struct *task = bpf_get_current_task_btf();
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if (task->pid != tid)
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return 0;
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/* If dead code elimination kicks in, the increment +=2 will be
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* removed. For raw_tp programs attaching to tracepoints in kernel
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* modules, we mark input arguments as PTR_MAYBE_NULL, so branch
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* prediction should never kick in.
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*/
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asm volatile ("%[i] += 1; if %[ctx] != 0 goto +1; %[i] += 2;"
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: [i]"+r"(i)
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: [ctx]"r"(skb)
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: "memory");
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return 0;
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}
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