root/usr/src/test/os-tests/tests/xsave/setcontext_replace.c
/*
 * This file and its contents are supplied under the terms of the
 * Common Development and Distribution License ("CDDL"), version 1.0.
 * You may only use this file in accordance with the terms of version
 * 1.0 of the CDDL.
 *
 * A full copy of the text of the CDDL should have accompanied this
 * source.  A copy of the CDDL is also available via the Internet at
 * http://www.illumos.org/license/CDDL.
 */

/*
 * Copyright 2023 Oxide Computer Company
 */

/*
 * The purpose of this program is to go through and replace all the FPU
 * registers in the floating point state in a ucontext_t and verify that we see
 * what we expected here.
 */

#include <err.h>
#include <stdlib.h>
#include <ucontext.h>

#include "xsave_util.h"

xsu_fpu_t to_set, found;

static void
setcontext_replace_check(uint32_t hwsup)
{
        xsu_getfpu(&found, hwsup);
        if (xsu_same(&to_set, &found, hwsup)) {
                (void) printf("TEST PASSED: setcontext() correctly wrote FPU "
                    "contents\n");
                exit(EXIT_SUCCESS);
        } else {
                errx(EXIT_FAILURE, "TEST_FAILED: setcontext() did not write "
                    "full FPU state");
        }
}

int
main(void)
{
        ucontext_t *ctx;
        uint32_t start = arc4random();
        uint32_t hwsup = xsu_hwsupport();

        ctx = ucontext_alloc(0);
        if (ctx == NULL) {
                err(EXIT_FAILURE, "failed to get allocate ucontext_t");
        }
        (void) printf("filling starting at 0x%x\n", start);
        xsu_fill(&to_set, hwsup, start);
        if (getcontext_extd(ctx, 0) != 0) {
                err(EXIT_FAILURE, "failed to get extended context");
        }

        xsu_overwrite_uctx(ctx, &to_set, hwsup);
        xsu_ustack_alloc(ctx);
        makecontext(ctx, setcontext_replace_check, 1, hwsup);
        (void) setcontext(ctx);

        err(EXIT_FAILURE, "TEST FAILED: set context did not work!");
}