tm-signal-context-chk-gpr.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_GPR_REGS 18 /* Number of non-volatile GPR registers */
 33#define R14 14 /* First non-volatile register to check in r14-r31 subset */
 34
 35long tm_signal_self_context_load(pid_t pid, long *gprs, double *fps, vector int *vms, vector int *vss);
 36
 37static sig_atomic_t fail, broken;
 38
 39/* Test only non-volatile general purpose registers, i.e. r14-r31 */
 40static long gprs[] = {
 41	/* First context will be set with these values, i.e. non-speculative */
 42	/* R14, R15, ... */
 43	 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,
 44	/* Second context will be set with these values, i.e. speculative */
 45	/* R14, R15, ... */
 46	-1,-2,-3,-4,-5,-6,-7,-8,-9,-10,-11,-12,-13,-14,-15,-16,-17,-18
 47};
 48
 49static void signal_usr1(int signum, siginfo_t *info, void *uc)
 50{
 51	int i;
 52	ucontext_t *ucp = uc;
 53	ucontext_t *tm_ucp = ucp->uc_link;
 54
 55	/* Check first context. Print all mismatches. */
 56	for (i = 0; i < NV_GPR_REGS; i++) {
 57		fail = (ucp->uc_mcontext.gp_regs[R14 + i] != gprs[i]);
 58		if (fail) {
 59			broken = 1;
 60			printf("GPR%d (1st context) == %lu instead of %lu (expected)\n",
 61				R14 + i, ucp->uc_mcontext.gp_regs[R14 + i], gprs[i]);
 62		}
 63	}
 64
 65	/* Check second context. Print all mismatches. */
 66	for (i = 0; i < NV_GPR_REGS; i++) {
 67		fail = (tm_ucp->uc_mcontext.gp_regs[R14 + i] != gprs[NV_GPR_REGS + i]);
 68		if (fail) {
 69			broken = 1;
 70			printf("GPR%d (2nd context) == %lu instead of %lu (expected)\n",
 71				R14 + i, tm_ucp->uc_mcontext.gp_regs[R14 + i], gprs[NV_GPR_REGS + i]);
 72		}
 73	}
 74}
 75
 76static int tm_signal_context_chk_gpr()
 77{
 78	struct sigaction act;
 79	int i;
 80	long rc;
 81	pid_t pid = getpid();
 82
 83	SKIP_IF(!have_htm());
 84	SKIP_IF(htm_is_synthetic());
 85
 86	act.sa_sigaction = signal_usr1;
 87	sigemptyset(&act.sa_mask);
 88	act.sa_flags = SA_SIGINFO;
 89	if (sigaction(SIGUSR1, &act, NULL) < 0) {
 90		perror("sigaction sigusr1");
 91		exit(1);
 92	}
 93
 94	i = 0;
 95	while (i < MAX_ATTEMPT && !broken) {
 96                /*
 97                 * tm_signal_self_context_load will set both first and second
 98                 * contexts accordingly to the values passed through non-NULL
 99                 * array pointers to it, in that case 'gprs', and invoke the
100                 * signal handler installed for SIGUSR1.
101                 */
102		rc = tm_signal_self_context_load(pid, gprs, NULL, NULL, NULL);
103		FAIL_IF(rc != pid);
104		i++;
105	}
106
107	return broken;
108}
109
110int main(void)
111{
112	return test_harness(tm_signal_context_chk_gpr, "tm_signal_context_chk_gpr");
113}