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/*
* Copyright(c) 2021 Qualcomm Innovation Center, Inc. All Rights Reserved.
*
* 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.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <fcntl.h>
#include <setjmp.h>
#include <signal.h>
int err;
static void __check(const char *filename, int line, int x, int expect)
{
if (x != expect) {
printf("ERROR %s:%d - %d != %d\n",
filename, line, x, expect);
err++;
}
}
#define check(x, expect) __check(__FILE__, __LINE__, (x), (expect))
static int satub(int src, int *p, int *ovf_result)
{
int result;
int usr;
/*
* This instruction can set bit 0 (OVF/overflow) in usr
* Clear the bit first, then return that bit to the caller
*
* We also store the src into *p in the same packet, so we
* can ensure the overflow doesn't get set when an exception
* is generated.
*/
asm volatile("r2 = usr\n\t"
"r2 = clrbit(r2, #0)\n\t" /* clear overflow bit */
"usr = r2\n\t"
"{\n\t"
" %0 = satub(%2)\n\t"
" memw(%3) = %2\n\t"
"}\n\t"
"%1 = usr\n\t"
: "=r"(result), "=r"(usr)
: "r"(src), "r"(p)
: "r2", "usr", "memory");
*ovf_result = (usr & 1);
return result;
}
int read_usr_overflow(void)
{
int result;
asm volatile("%0 = usr\n\t" : "=r"(result));
return result & 1;
}
jmp_buf jmp_env;
int usr_overflow;
static void sig_segv(int sig, siginfo_t *info, void *puc)
{
usr_overflow = read_usr_overflow();
longjmp(jmp_env, 1);
}
int main()
{
struct sigaction act;
int ovf;
/* SIGSEGV test */
act.sa_sigaction = sig_segv;
sigemptyset(&act.sa_mask);
act.sa_flags = SA_SIGINFO;
sigaction(SIGSEGV, &act, NULL);
if (setjmp(jmp_env) == 0) {
satub(300, 0, &ovf);
}
act.sa_handler = SIG_DFL;
sigemptyset(&act.sa_mask);
act.sa_flags = 0;
check(usr_overflow, 0);
puts(err ? "FAIL" : "PASS");
return err ? EXIT_FAILURE : EXIT_SUCCESS;
}
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