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// SPDX-License-Identifier: GPL-2.0-only
/*
* POWER Data Stream Control Register (DSCR) fork exec test
*
* This testcase modifies the DSCR using mtspr, forks & execs and
* verifies that the child is using the changed DSCR using mfspr.
*
* When using the privilege state SPR, the instructions such as
* mfspr or mtspr are privileged and the kernel emulates them
* for us. Instructions using problem state SPR can be executed
* directly without any emulation if the HW supports them. Else
* they also get emulated by the kernel.
*
* Copyright 2012, Anton Blanchard, IBM Corporation.
* Copyright 2015, Anshuman Khandual, IBM Corporation.
*/
#include "dscr.h"
static char *prog;
static void do_exec(unsigned long parent_dscr)
{
unsigned long cur_dscr, cur_dscr_usr;
cur_dscr = get_dscr();
cur_dscr_usr = get_dscr_usr();
if (cur_dscr != parent_dscr) {
fprintf(stderr, "Parent DSCR %ld was not inherited "
"over exec (kernel value)\n", parent_dscr);
exit(1);
}
if (cur_dscr_usr != parent_dscr) {
fprintf(stderr, "Parent DSCR %ld was not inherited "
"over exec (user value)\n", parent_dscr);
exit(1);
}
exit(0);
}
int dscr_inherit_exec(void)
{
unsigned long i, dscr = 0;
pid_t pid;
SKIP_IF(!have_hwcap2(PPC_FEATURE2_DSCR));
for (i = 0; i < COUNT; i++) {
dscr++;
if (dscr > DSCR_MAX)
dscr = 0;
if (dscr == get_default_dscr())
continue;
if (i % 2 == 0)
set_dscr_usr(dscr);
else
set_dscr(dscr);
pid = fork();
if (pid == -1) {
perror("fork() failed");
exit(1);
} else if (pid) {
int status;
if (waitpid(pid, &status, 0) == -1) {
perror("waitpid() failed");
exit(1);
}
if (!WIFEXITED(status)) {
fprintf(stderr, "Child didn't exit cleanly\n");
exit(1);
}
if (WEXITSTATUS(status) != 0) {
fprintf(stderr, "Child didn't exit cleanly\n");
return 1;
}
} else {
char dscr_str[16];
sprintf(dscr_str, "%ld", dscr);
execlp(prog, prog, "exec", dscr_str, NULL);
exit(1);
}
}
return 0;
}
int main(int argc, char *argv[])
{
if (argc == 3 && !strcmp(argv[1], "exec")) {
unsigned long parent_dscr;
parent_dscr = atoi(argv[2]);
do_exec(parent_dscr);
} else if (argc != 1) {
fprintf(stderr, "Usage: %s\n", argv[0]);
exit(1);
}
prog = argv[0];
return test_harness(dscr_inherit_exec, "dscr_inherit_exec_test");
}
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