// SPDX-License-Identifier: GPL-2.0-only
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/*
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* POWER Data Stream Control Register (DSCR) fork test
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*
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* This testcase modifies the DSCR using mtspr, forks and then
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* verifies that the child process has the correct changed DSCR
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* value using mfspr.
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*
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* When using the privilege state SPR, the instructions such as
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* mfspr or mtspr are priviledged and the kernel emulates them
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* for us. Instructions using problem state SPR can be exuecuted
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* directly without any emulation if the HW supports them. Else
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* they also get emulated by the kernel.
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*
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* Copyright 2012, Anton Blanchard, IBM Corporation.
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* Copyright 2015, Anshuman Khandual, IBM Corporation.
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*/
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#include "dscr.h"
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int dscr_inherit(void)
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{
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unsigned long i, dscr = 0;
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pid_t pid;
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SKIP_IF(!have_hwcap2(PPC_FEATURE2_DSCR));
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srand(getpid());
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set_dscr(dscr);
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for (i = 0; i < COUNT; i++) {
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unsigned long cur_dscr, cur_dscr_usr;
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dscr++;
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if (dscr > DSCR_MAX)
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dscr = 0;
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if (i % 2 == 0)
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set_dscr_usr(dscr);
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else
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set_dscr(dscr);
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pid = fork();
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if (pid == -1) {
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perror("fork() failed");
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exit(1);
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} else if (pid) {
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int status;
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if (waitpid(pid, &status, 0) == -1) {
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perror("waitpid() failed");
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exit(1);
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}
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if (!WIFEXITED(status)) {
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fprintf(stderr, "Child didn't exit cleanly\n");
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exit(1);
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}
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if (WEXITSTATUS(status) != 0) {
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fprintf(stderr, "Child didn't exit cleanly\n");
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return 1;
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}
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} else {
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cur_dscr = get_dscr();
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if (cur_dscr != dscr) {
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fprintf(stderr, "Kernel DSCR should be %ld "
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"but is %ld\n", dscr, cur_dscr);
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exit(1);
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}
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cur_dscr_usr = get_dscr_usr();
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if (cur_dscr_usr != dscr) {
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fprintf(stderr, "User DSCR should be %ld "
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"but is %ld\n", dscr, cur_dscr_usr);
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exit(1);
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}
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exit(0);
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}
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}
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return 0;
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}
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int main(int argc, char *argv[])
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{
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return test_harness(dscr_inherit, "dscr_inherit_test");
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}
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