tm-signal-context-chk-fpu.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * Copyright 2016, Cyril Bur, IBM Corp.
  4 *
  5 * Test the kernel's signal frame code.
  6 *
  7 * The kernel sets up two sets of ucontexts if the signal was to be
  8 * delivered while the thread was in a transaction (referred too as
  9 * first and second contexts).
 10 * Expected behaviour is that the checkpointed state is in the user
 11 * context passed to the signal handler (first context). The speculated
 12 * state can be accessed with the uc_link pointer (second context).
 13 *
 14 * The rationale for this is that if TM unaware code (which linked
 15 * against TM libs) installs a signal handler it will not know of the
 16 * speculative nature of the 'live' registers and may infer the wrong
 17 * thing.
 18 */
 19
 20#include <stdlib.h>
 21#include <stdio.h>
 22#include <signal.h>
 23#include <unistd.h>
 24
 25#include <altivec.h>
 26
 27#include "utils.h"
 28#include "tm.h"
 29
 30#define MAX_ATTEMPT 500000
 31
 32#define NV_FPU_REGS 18 /* Number of non-volatile FP registers */
 33#define FPR14 14 /* First non-volatile FP register to check in f14-31 subset */
 34
 35long tm_signal_self_context_load(pid_t pid, long *gprs, double *fps, vector int *vms, vector int *vss);
 36
 37/* Test only non-volatile registers, i.e. 18 fpr registers from f14 to f31 */
 38static double fps[] = {
 39	/* First context will be set with these values, i.e. non-speculative */
 40	 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,
 41	/* Second context will be set with these values, i.e. speculative */
 42	-1,-2,-3,-4,-5,-6,-7,-8,-9,-10,-11,-12,-13,-14,-15,-16,-17,-18
 43};
 44
 45static sig_atomic_t fail, broken;
 46
 47static void signal_usr1(int signum, siginfo_t *info, void *uc)
 48{
 49	int i;
 50	ucontext_t *ucp = uc;
 51	ucontext_t *tm_ucp = ucp->uc_link;
 52
 53	for (i = 0; i < NV_FPU_REGS; i++) {
 54		/* Check first context. Print all mismatches. */
 55		fail = (ucp->uc_mcontext.fp_regs[FPR14 + i] != fps[i]);
 56		if (fail) {
 57			broken = 1;
 58			printf("FPR%d (1st context) == %g instead of %g (expected)\n",
 59				FPR14 + i, ucp->uc_mcontext.fp_regs[FPR14 + i], fps[i]);
 60		}
 61	}
 62
 63	for (i = 0; i < NV_FPU_REGS; i++) {
 64		/* Check second context. Print all mismatches. */
 65		fail = (tm_ucp->uc_mcontext.fp_regs[FPR14 + i] != fps[NV_FPU_REGS + i]);
 66		if (fail) {
 67			broken = 1;
 68			printf("FPR%d (2nd context) == %g instead of %g (expected)\n",
 69				FPR14 + i, tm_ucp->uc_mcontext.fp_regs[FPR14 + i], fps[NV_FPU_REGS + i]);
 70		}
 71	}
 72}
 73
 74static int tm_signal_context_chk_fpu()
 75{
 76	struct sigaction act;
 77	int i;
 78	long rc;
 79	pid_t pid = getpid();
 80
 81	SKIP_IF(!have_htm());
 82	SKIP_IF(htm_is_synthetic());
 83
 84	act.sa_sigaction = signal_usr1;
 85	sigemptyset(&act.sa_mask);
 86	act.sa_flags = SA_SIGINFO;
 87	if (sigaction(SIGUSR1, &act, NULL) < 0) {
 88		perror("sigaction sigusr1");
 89		exit(1);
 90	}
 91
 92	i = 0;
 93	while (i < MAX_ATTEMPT && !broken) {
 94		/*
 95		 * tm_signal_self_context_load will set both first and second
 96		 * contexts accordingly to the values passed through non-NULL
 97		 * array pointers to it, in that case 'fps', and invoke the
 98		 * signal handler installed for SIGUSR1.
 99		 */
100		rc = tm_signal_self_context_load(pid, NULL, fps, NULL, NULL);
101		FAIL_IF(rc != pid);
102		i++;
103	}
104
105	return (broken);
106}
107
108int main(void)
109{
110	return test_harness(tm_signal_context_chk_fpu, "tm_signal_context_chk_fpu");
111}