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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fpu_signal.c (2918B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 * Copyright 2015, Cyril Bur, IBM Corp.
      4 *
      5 * This test attempts to see if the FPU registers are correctly reported in a
      6 * signal context. Each worker just spins checking its FPU registers, at some
      7 * point a signal will interrupt it and C code will check the signal context
      8 * ensuring it is also the same.
      9 */
     10
     11#include <stdio.h>
     12#include <unistd.h>
     13#include <sys/syscall.h>
     14#include <sys/time.h>
     15#include <sys/types.h>
     16#include <sys/wait.h>
     17#include <stdlib.h>
     18#include <pthread.h>
     19
     20#include "utils.h"
     21
     22/* Number of times each thread should receive the signal */
     23#define ITERATIONS 10
     24/*
     25 * Factor by which to multiply number of online CPUs for total number of
     26 * worker threads
     27 */
     28#define THREAD_FACTOR 8
     29
     30__thread double darray[] = {0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0,
     31		     1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0,
     32		     2.1};
     33
     34bool bad_context;
     35int threads_starting;
     36int running;
     37
     38extern long preempt_fpu(double *darray, int *threads_starting, int *running);
     39
     40void signal_fpu_sig(int sig, siginfo_t *info, void *context)
     41{
     42	int i;
     43	ucontext_t *uc = context;
     44	mcontext_t *mc = &uc->uc_mcontext;
     45
     46	/* Only the non volatiles were loaded up */
     47	for (i = 14; i < 32; i++) {
     48		if (mc->fp_regs[i] != darray[i - 14]) {
     49			bad_context = true;
     50			break;
     51		}
     52	}
     53}
     54
     55void *signal_fpu_c(void *p)
     56{
     57	int i;
     58	long rc;
     59	struct sigaction act;
     60	act.sa_sigaction = signal_fpu_sig;
     61	act.sa_flags = SA_SIGINFO;
     62	rc = sigaction(SIGUSR1, &act, NULL);
     63	if (rc)
     64		return p;
     65
     66	srand(pthread_self());
     67	for (i = 0; i < 21; i++)
     68		darray[i] = rand();
     69
     70	rc = preempt_fpu(darray, &threads_starting, &running);
     71
     72	return (void *) rc;
     73}
     74
     75int test_signal_fpu(void)
     76{
     77	int i, j, rc, threads;
     78	void *rc_p;
     79	pthread_t *tids;
     80
     81	threads = sysconf(_SC_NPROCESSORS_ONLN) * THREAD_FACTOR;
     82	tids = malloc(threads * sizeof(pthread_t));
     83	FAIL_IF(!tids);
     84
     85	running = true;
     86	threads_starting = threads;
     87	for (i = 0; i < threads; i++) {
     88		rc = pthread_create(&tids[i], NULL, signal_fpu_c, NULL);
     89		FAIL_IF(rc);
     90	}
     91
     92	setbuf(stdout, NULL);
     93	printf("\tWaiting for all workers to start...");
     94	while (threads_starting)
     95		asm volatile("": : :"memory");
     96	printf("done\n");
     97
     98	printf("\tSending signals to all threads %d times...", ITERATIONS);
     99	for (i = 0; i < ITERATIONS; i++) {
    100		for (j = 0; j < threads; j++) {
    101			pthread_kill(tids[j], SIGUSR1);
    102		}
    103		sleep(1);
    104	}
    105	printf("done\n");
    106
    107	printf("\tStopping workers...");
    108	running = 0;
    109	for (i = 0; i < threads; i++) {
    110		pthread_join(tids[i], &rc_p);
    111
    112		/*
    113		 * Harness will say the fail was here, look at why signal_fpu
    114		 * returned
    115		 */
    116		if ((long) rc_p || bad_context)
    117			printf("oops\n");
    118		if (bad_context)
    119			fprintf(stderr, "\t!! bad_context is true\n");
    120		FAIL_IF((long) rc_p || bad_context);
    121	}
    122	printf("done\n");
    123
    124	free(tids);
    125	return 0;
    126}
    127
    128int main(int argc, char *argv[])
    129{
    130	return test_harness(test_signal_fpu, "fpu_signal");
    131}