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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test_rdonly_maps.c (1760B)

      1// SPDX-License-Identifier: GPL-2.0
      2// Copyright (c) 2019 Facebook
      3
      4#include <linux/ptrace.h>
      5#include <linux/bpf.h>
      6#include <bpf/bpf_helpers.h>
      7
      8const struct {
      9	unsigned a[4];
     10	/*
     11	 * if the struct's size is multiple of 16, compiler will put it into
     12	 * .rodata.cst16 section, which is not recognized by libbpf; work
     13	 * around this by ensuring we don't have 16-aligned struct
     14	 */
     15	char _y;
     16} rdonly_values = { .a = {2, 3, 4, 5} };
     17
     18struct {
     19	unsigned did_run;
     20	unsigned iters;
     21	unsigned sum;
     22} res = {};
     23
     24SEC("raw_tracepoint/sys_enter:skip_loop")
     25int skip_loop(struct pt_regs *ctx)
     26{
     27	/* prevent compiler to optimize everything out */
     28	unsigned * volatile p = (void *)&rdonly_values.a;
     29	unsigned iters = 0, sum = 0;
     30
     31	/* we should never enter this loop */
     32	while (*p & 1) {
     33		iters++;
     34		sum += *p;
     35		p++;
     36	}
     37	res.did_run = 1;
     38	res.iters = iters;
     39	res.sum = sum;
     40	return 0;
     41}
     42
     43SEC("raw_tracepoint/sys_enter:part_loop")
     44int part_loop(struct pt_regs *ctx)
     45{
     46	/* prevent compiler to optimize everything out */
     47	unsigned * volatile p = (void *)&rdonly_values.a;
     48	unsigned iters = 0, sum = 0;
     49
     50	/* validate verifier can derive loop termination */
     51	while (*p < 5) {
     52		iters++;
     53		sum += *p;
     54		p++;
     55	}
     56	res.did_run = 1;
     57	res.iters = iters;
     58	res.sum = sum;
     59	return 0;
     60}
     61
     62SEC("raw_tracepoint/sys_enter:full_loop")
     63int full_loop(struct pt_regs *ctx)
     64{
     65	/* prevent compiler to optimize everything out */
     66	unsigned * volatile p = (void *)&rdonly_values.a;
     67	int i = sizeof(rdonly_values.a) / sizeof(rdonly_values.a[0]);
     68	unsigned iters = 0, sum = 0;
     69
     70	/* validate verifier can allow full loop as well */
     71	while (i > 0 ) {
     72		iters++;
     73		sum += *p;
     74		p++;
     75		i--;
     76	}
     77	res.did_run = 1;
     78	res.iters = iters;
     79	res.sum = sum;
     80	return 0;
     81}
     82
     83char _license[] SEC("license") = "GPL";