cregit-Linux how code gets into the kernel

Release 4.10 tools/testing/selftests/powerpc/tm/tm-signal-context-chk-fpu.c

/*
 * Copyright 2016, Cyril Bur, IBM Corp.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 *
 *
 * Test the kernel's signal frame code.
 *
 * The kernel sets up two sets of ucontexts if the signal was to be
 * delivered while the thread was in a transaction.
 * Expected behaviour is that the checkpointed state is in the user
 * context passed to the signal handler. The speculated state can be
 * accessed with the uc_link pointer.
 *
 * The rationale for this is that if TM unaware code (which linked
 * against TM libs) installs a signal handler it will not know of the
 * speculative nature of the 'live' registers and may infer the wrong
 * thing.
 */

#include <stdlib.h>
#include <stdio.h>
#include <signal.h>
#include <unistd.h>

#include <altivec.h>

#include "utils.h"
#include "tm.h"


#define MAX_ATTEMPT 500000


#define NV_FPU_REGS 18

long tm_signal_self_context_load(pid_t pid, long *gprs, double *fps, vector int *vms, vector int *vss);

/* Be sure there are 2x as many as there are NV FPU regs (2x18) */

static double fps[] = {
	 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18,
	-1,-2,-3,-4,-5,-6,-7,-8,-9,-10,-11,-12,-13,-14,-15,-16,-17,-18
};


static sig_atomic_t fail;


static void signal_usr1(int signum, siginfo_t *info, void *uc) { int i; ucontext_t *ucp = uc; ucontext_t *tm_ucp = ucp->uc_link; for (i = 0; i < NV_FPU_REGS && !fail; i++) { fail = (ucp->uc_mcontext.fp_regs[i + 14] != fps[i]); fail |= (tm_ucp->uc_mcontext.fp_regs[i + 14] != fps[i + NV_FPU_REGS]); if (fail) printf("Failed on %d FP %g or %g\n", i, ucp->uc_mcontext.fp_regs[i + 14], tm_ucp->uc_mcontext.fp_regs[i + 14]); } }

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static int tm_signal_context_chk_fpu() { struct sigaction act; int i; long rc; pid_t pid = getpid(); SKIP_IF(!have_htm()); act.sa_sigaction = signal_usr1; sigemptyset(&act.sa_mask); act.sa_flags = SA_SIGINFO; if (sigaction(SIGUSR1, &act, NULL) < 0) { perror("sigaction sigusr1"); exit(1); } i = 0; while (i < MAX_ATTEMPT && !fail) { rc = tm_signal_self_context_load(pid, NULL, fps, NULL, NULL); FAIL_IF(rc != pid); i++; } return fail; }

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int main(void) { return test_harness(tm_signal_context_chk_fpu, "tm_signal_context_chk_fpu"); }

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