cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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bperf_follower.bpf.c (1764B)

      1// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
      2// Copyright (c) 2021 Facebook
      3#include "vmlinux.h"
      4#include <bpf/bpf_helpers.h>
      5#include <bpf/bpf_tracing.h>
      6#include "bperf_u.h"
      7
      8struct {
      9	__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
     10	__uint(key_size, sizeof(__u32));
     11	__uint(value_size, sizeof(struct bpf_perf_event_value));
     12	__uint(max_entries, 1);
     13} diff_readings SEC(".maps");
     14
     15struct {
     16	__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
     17	__uint(key_size, sizeof(__u32));
     18	__uint(value_size, sizeof(struct bpf_perf_event_value));
     19	__uint(max_entries, 1);
     20} accum_readings SEC(".maps");
     21
     22struct {
     23	__uint(type, BPF_MAP_TYPE_HASH);
     24	__uint(key_size, sizeof(__u32));
     25	__uint(value_size, sizeof(__u32));
     26} filter SEC(".maps");
     27
     28enum bperf_filter_type type = 0;
     29int enabled = 0;
     30
     31SEC("fexit/XXX")
     32int BPF_PROG(fexit_XXX)
     33{
     34	struct bpf_perf_event_value *diff_val, *accum_val;
     35	__u32 filter_key, zero = 0;
     36	__u32 *accum_key;
     37
     38	if (!enabled)
     39		return 0;
     40
     41	switch (type) {
     42	case BPERF_FILTER_GLOBAL:
     43		accum_key = &zero;
     44		goto do_add;
     45	case BPERF_FILTER_CPU:
     46		filter_key = bpf_get_smp_processor_id();
     47		break;
     48	case BPERF_FILTER_PID:
     49		filter_key = bpf_get_current_pid_tgid() & 0xffffffff;
     50		break;
     51	case BPERF_FILTER_TGID:
     52		filter_key = bpf_get_current_pid_tgid() >> 32;
     53		break;
     54	default:
     55		return 0;
     56	}
     57
     58	accum_key = bpf_map_lookup_elem(&filter, &filter_key);
     59	if (!accum_key)
     60		return 0;
     61
     62do_add:
     63	diff_val = bpf_map_lookup_elem(&diff_readings, &zero);
     64	if (!diff_val)
     65		return 0;
     66
     67	accum_val = bpf_map_lookup_elem(&accum_readings, accum_key);
     68	if (!accum_val)
     69		return 0;
     70
     71	accum_val->counter += diff_val->counter;
     72	accum_val->enabled += diff_val->enabled;
     73	accum_val->running += diff_val->running;
     74
     75	return 0;
     76}
     77
     78char LICENSE[] SEC("license") = "Dual BSD/GPL";