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authorAnshuman Khandual <khandual@linux.vnet.ibm.com>2015-05-21 12:13:09 +0530
committerMichael Ellerman <mpe@ellerman.id.au>2015-06-07 19:37:11 +1000
commitcf9c4a5ecf806348940ee26b7ff0ff59f5530059 (patch)
tree449e44ab945ecadc1e1eb3bfbedb74f761566783 /tools
parentcc6a93f1c3d6923ebf2f305416d080e9afc7ee95 (diff)
downloadop-kernel-dev-cf9c4a5ecf806348940ee26b7ff0ff59f5530059.zip
op-kernel-dev-cf9c4a5ecf806348940ee26b7ff0ff59f5530059.tar.gz
selftests/powerpc: Add test for DSCR value inheritence across fork
This patch adds a test to verify that the changed DSCR value inside any process would be inherited to it's child process across the fork system call. Acked-by: Shuah Khan <shuahkh@osg.samsung.com> Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com> Signed-off-by: Anton Blanchard <anton@samba.org> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'tools')
-rw-r--r--tools/testing/selftests/powerpc/dscr/Makefile3
-rw-r--r--tools/testing/selftests/powerpc/dscr/dscr_inherit_test.c95
2 files changed, 97 insertions, 1 deletions
diff --git a/tools/testing/selftests/powerpc/dscr/Makefile b/tools/testing/selftests/powerpc/dscr/Makefile
index 3c3856b..764fadc 100644
--- a/tools/testing/selftests/powerpc/dscr/Makefile
+++ b/tools/testing/selftests/powerpc/dscr/Makefile
@@ -1,4 +1,5 @@
-TEST_PROGS := dscr_default_test dscr_explicit_test dscr_user_test
+TEST_PROGS := dscr_default_test dscr_explicit_test dscr_user_test \
+ dscr_inherit_test
dscr_default_test: LDLIBS += -lpthread
diff --git a/tools/testing/selftests/powerpc/dscr/dscr_inherit_test.c b/tools/testing/selftests/powerpc/dscr/dscr_inherit_test.c
new file mode 100644
index 0000000..4e414ca
--- /dev/null
+++ b/tools/testing/selftests/powerpc/dscr/dscr_inherit_test.c
@@ -0,0 +1,95 @@
+/*
+ * POWER Data Stream Control Register (DSCR) fork test
+ *
+ * This testcase modifies the DSCR using mtspr, forks and then
+ * verifies that the child process has the correct changed DSCR
+ * value using mfspr.
+ *
+ * When using the privilege state SPR, the instructions such as
+ * mfspr or mtspr are priviledged and the kernel emulates them
+ * for us. Instructions using problem state SPR can be exuecuted
+ * 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.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+#include "dscr.h"
+
+int dscr_inherit(void)
+{
+ unsigned long i, dscr = 0;
+ pid_t pid;
+
+ srand(getpid());
+ set_dscr(dscr);
+
+ for (i = 0; i < COUNT; i++) {
+ unsigned long cur_dscr, cur_dscr_usr;
+
+ dscr++;
+ if (dscr > DSCR_MAX)
+ dscr = 0;
+
+ if (i % 2 == 0)
+ set_dscr_usr(dscr);
+ else
+ set_dscr(dscr);
+
+ /*
+ * XXX: Force a context switch out so that DSCR
+ * current value is copied into the thread struct
+ * which is required for the child to inherit the
+ * changed value.
+ */
+ sleep(1);
+
+ 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 {
+ cur_dscr = get_dscr();
+ if (cur_dscr != dscr) {
+ fprintf(stderr, "Kernel DSCR should be %ld "
+ "but is %ld\n", dscr, cur_dscr);
+ exit(1);
+ }
+
+ cur_dscr_usr = get_dscr_usr();
+ if (cur_dscr_usr != dscr) {
+ fprintf(stderr, "User DSCR should be %ld "
+ "but is %ld\n", dscr, cur_dscr_usr);
+ exit(1);
+ }
+ exit(0);
+ }
+ }
+ return 0;
+}
+
+int main(int argc, char *argv[])
+{
+ return test_harness(dscr_inherit, "dscr_inherit_test");
+}
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