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-rw-r--r--tools/testing/selftests/powerpc/tm/tm-resched-dscr.c100
1 files changed, 100 insertions, 0 deletions
diff --git a/tools/testing/selftests/powerpc/tm/tm-resched-dscr.c b/tools/testing/selftests/powerpc/tm/tm-resched-dscr.c
new file mode 100644
index 000000000..4cdb83964
--- /dev/null
+++ b/tools/testing/selftests/powerpc/tm/tm-resched-dscr.c
@@ -0,0 +1,100 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Test context switching to see if the DSCR SPR is correctly preserved
+ * when within a transaction.
+ *
+ * Note: We assume that the DSCR has been left at the default value (0)
+ * for all CPUs.
+ *
+ * Method:
+ *
+ * Set a value into the DSCR.
+ *
+ * Start a transaction, and suspend it (*).
+ *
+ * Hard loop checking to see if the transaction has become doomed.
+ *
+ * Now that we *may* have been preempted, record the DSCR and TEXASR SPRS.
+ *
+ * If the abort was because of a context switch, check the DSCR value.
+ * Otherwise, try again.
+ *
+ * (*) If the transaction is not suspended we can't see the problem because
+ * the transaction abort handler will restore the DSCR to it's checkpointed
+ * value before we regain control.
+ */
+
+#include <inttypes.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <asm/tm.h>
+
+#include "utils.h"
+#include "tm.h"
+#include "../pmu/lib.h"
+
+#define SPRN_DSCR 0x03
+
+int test_body(void)
+{
+ uint64_t rv, dscr1 = 1, dscr2, texasr;
+
+ SKIP_IF(!have_htm());
+
+ printf("Check DSCR TM context switch: ");
+ fflush(stdout);
+ for (;;) {
+ asm __volatile__ (
+ /* set a known value into the DSCR */
+ "ld 3, %[dscr1];"
+ "mtspr %[sprn_dscr], 3;"
+
+ "li %[rv], 1;"
+ /* start and suspend a transaction */
+ "tbegin.;"
+ "beq 1f;"
+ "tsuspend.;"
+
+ /* hard loop until the transaction becomes doomed */
+ "2: ;"
+ "tcheck 0;"
+ "bc 4, 0, 2b;"
+
+ /* record DSCR and TEXASR */
+ "mfspr 3, %[sprn_dscr];"
+ "std 3, %[dscr2];"
+ "mfspr 3, %[sprn_texasr];"
+ "std 3, %[texasr];"
+
+ "tresume.;"
+ "tend.;"
+ "li %[rv], 0;"
+ "1: ;"
+ : [rv]"=r"(rv), [dscr2]"=m"(dscr2), [texasr]"=m"(texasr)
+ : [dscr1]"m"(dscr1)
+ , [sprn_dscr]"i"(SPRN_DSCR), [sprn_texasr]"i"(SPRN_TEXASR)
+ : "memory", "r3"
+ );
+ assert(rv); /* make sure the transaction aborted */
+ if ((texasr >> 56) != TM_CAUSE_RESCHED) {
+ continue;
+ }
+ if (dscr2 != dscr1) {
+ printf(" FAIL\n");
+ return 1;
+ } else {
+ printf(" OK\n");
+ return 0;
+ }
+ }
+}
+
+static int tm_resched_dscr(void)
+{
+ return eat_cpu(test_body);
+}
+
+int main(int argc, const char *argv[])
+{
+ return test_harness(tm_resched_dscr, "tm_resched_dscr");
+}