Generate specification exceptions and check that they occur.
Signed-off-by: Janis Schoetterl-Glausch <scgl@xxxxxxxxxxxxx>
---
s390x/Makefile | 1 +
lib/s390x/asm/arch_def.h | 5 +
s390x/spec_ex.c | 194 +++++++++++++++++++++++++++++++++++++++
s390x/unittests.cfg | 3 +
4 files changed, 203 insertions(+)
create mode 100644 s390x/spec_ex.c
diff --git a/s390x/Makefile b/s390x/Makefile
index efd5e0c1..58b1bf54 100644
--- a/s390x/Makefile
+++ b/s390x/Makefile
@@ -27,6 +27,7 @@ tests += $(TEST_DIR)/uv-host.elf
tests += $(TEST_DIR)/edat.elf
tests += $(TEST_DIR)/mvpg-sie.elf
tests += $(TEST_DIR)/spec_ex-sie.elf
+tests += $(TEST_DIR)/spec_ex.elf
tests += $(TEST_DIR)/firq.elf
tests += $(TEST_DIR)/epsw.elf
tests += $(TEST_DIR)/adtl-status.elf
diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h
index e7ae454b..b6e60fb0 100644
--- a/lib/s390x/asm/arch_def.h
+++ b/lib/s390x/asm/arch_def.h
@@ -41,6 +41,11 @@ struct psw {
uint64_t addr;
};
+struct short_psw {
+ uint32_t mask;
+ uint32_t addr;
+};
+
struct cpu {
struct lowcore *lowcore;
uint64_t *stack;
diff --git a/s390x/spec_ex.c b/s390x/spec_ex.c
new file mode 100644
index 00000000..68469e4b
--- /dev/null
+++ b/s390x/spec_ex.c
@@ -0,0 +1,194 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright IBM Corp. 2021, 2022
+ *
+ * Specification exception test.
+ * Tests that specification exceptions occur when expected.
+ *
+ * Can be extended by adding triggers to spec_ex_triggers, see comments below.
+ */
+#include <stdlib.h>
+#include <libcflat.h>
+#include <bitops.h>
+#include <asm/interrupt.h>
+
+/* toggled to signal occurrence of invalid psw fixup */
+static bool invalid_psw_expected;
+static struct psw expected_psw;
+static struct psw invalid_psw;
+static struct psw fixup_psw;
+
+/*
+ * The standard program exception handler cannot deal with invalid old PSWs,
+ * especially not invalid instruction addresses, as in that case one cannot
+ * find the instruction following the faulting one from the old PSW.
+ * The PSW to return to is set by load_psw.
+ */
+static void fixup_invalid_psw(struct stack_frame_int *stack)
+{
+ /* signal occurrence of invalid psw fixup */
+ invalid_psw_expected = false;
+ invalid_psw = lowcore.pgm_old_psw;
+ lowcore.pgm_old_psw = fixup_psw;
+}
+
+/*
+ * Load possibly invalid psw, but setup fixup_psw before,
+ * so that fixup_invalid_psw() can bring us back onto the right track.
+ * Also acts as compiler barrier, -> none required in expect/check_invalid_psw
+ */
+static void load_psw(struct psw psw)
+{
+ uint64_t scratch;
+
+ /*
+ * The fixup psw is current psw with the instruction address replaced by
+ * the address of the nop following the instruction loading the new psw.
+ */
+ fixup_psw.mask = extract_psw_mask();
+ asm volatile ( "larl %[scratch],0f\n"
+ " stg %[scratch],%[fixup_addr]\n"
+ " lpswe %[psw]\n"
+ "0: nop\n"
+ : [scratch] "=&d" (scratch),
+ [fixup_addr] "=&T" (fixup_psw.addr)
+ : [psw] "Q" (psw)
+ : "cc", "memory"
+ );
+}
+
+static void load_short_psw(struct short_psw psw)
+{
+ uint64_t scratch;
+
+ fixup_psw.mask = extract_psw_mask();
+ asm volatile ( "larl %[scratch],0f\n"
+ " stg %[scratch],%[fixup_addr]\n"
+ " lpsw %[psw]\n"
+ "0: nop\n"
+ : [scratch] "=&d" (scratch),
+ [fixup_addr] "=&T" (fixup_psw.addr)
+ : [psw] "Q" (psw)
+ : "cc", "memory"
+ );
+}
+
+static void expect_invalid_psw(struct psw psw)
+{
+ expected_psw = psw;
+ invalid_psw_expected = true;
+}
+
+static int check_invalid_psw(void)
+{
+ if (!invalid_psw_expected) {
+ if (expected_psw.mask == invalid_psw.mask &&
+ expected_psw.addr == invalid_psw.addr)
+ return 0;
+ report_fail("Wrong invalid PSW");
+ } else {
+ report_fail("Expected exception due to invalid PSW");
+ }
+ return 1;
+}
+
+/* For normal PSWs bit 12 has to be 0 to be a valid PSW*/
+static int psw_bit_12_is_1(void)
+{
+ struct psw invalid = {
+ .mask = BIT(63 - 12),
+ .addr = 0x00000000deadbeee
+ };
+
+ expect_invalid_psw(invalid);
+ load_psw(invalid);
+ return check_invalid_psw();
+}
+
+/* A short PSW needs to have bit 12 set to be valid. */
+static int short_psw_bit_12_is_0(void)
+{
+ struct short_psw short_invalid = {
+ .mask = 0x0,
+ .addr = 0xdeadbeee
+ };
+
+ /*
+ * lpsw may optionally check bit 12 before loading the new psw
+ * -> cannot check the expected invalid psw like with lpswe
+ */
+ load_short_psw(short_invalid);
+ return 0;
+}
+
+static int bad_alignment(void)
+{
+ uint32_t words[5] __attribute__((aligned(16)));
+ uint32_t (*bad_aligned)[4] = (uint32_t (*)[4])&words[1];
+
+ /* LOAD PAIR FROM QUADWORD (LPQ) requires quadword alignment */
+ asm volatile ("lpq %%r6,%[bad]"
+ : : [bad] "T" (*bad_aligned)
+ : "%r6", "%r7"
+ );
+ return 0;
+}
+
+static int not_even(void)
+{
+ uint64_t quad[2] __attribute__((aligned(16))) = {0};
+
+ asm volatile (".insn rxy,0xe3000000008f,%%r7,%[quad]" /* lpq %%r7,%[quad] */
+ : : [quad] "T" (quad)
+ : "%r7", "%r8"
+ );
+ return 0;
+}
+
+/*
+ * Harness for specification exception testing.
+ * func only triggers exception, reporting is taken care of automatically.
+ */
+struct spec_ex_trigger {
+ const char *name;
+ int (*func)(void);
+ void (*fixup)(struct stack_frame_int *stack);
+};
+
+/* List of all tests to execute */
+static const struct spec_ex_trigger spec_ex_triggers[] = {
+ { "psw_bit_12_is_1", &psw_bit_12_is_1, &fixup_invalid_psw },
+ { "short_psw_bit_12_is_0", &short_psw_bit_12_is_0, &fixup_invalid_psw },
+ { "bad_alignment", &bad_alignment, NULL },
+ { "not_even", ¬_even, NULL },
+ { NULL, NULL, NULL },
+};
+
+static void test_spec_ex(const struct spec_ex_trigger *trigger)
+{
+ int rc;
+
+ expect_pgm_int();
+ register_pgm_cleanup_func(trigger->fixup);
+ rc = trigger->func();
+ register_pgm_cleanup_func(NULL);
+ /* test failed, nothing to be done, reporting responsibility of trigger */
+ if (rc)
+ return;
+ check_pgm_int_code(PGM_INT_CODE_SPECIFICATION);
+}
+
+int main(int argc, char **argv)
+{
+ unsigned int i;
+
+ report_prefix_push("specification exception");
+ for (i = 0; spec_ex_triggers[i].name; i++) {
+ report_prefix_push(spec_ex_triggers[i].name);
+ test_spec_ex(&spec_ex_triggers[i]);
+ report_prefix_pop();
+ }
+ report_prefix_pop();
+
+ return report_summary();
+}
diff --git a/s390x/unittests.cfg b/s390x/unittests.cfg
index f7b1fc3d..2ecaee1f 100644
--- a/s390x/unittests.cfg
+++ b/s390x/unittests.cfg
@@ -114,6 +114,9 @@ file = mvpg-sie.elf
[spec_ex-sie]
file = spec_ex-sie.elf
+[spec_ex]
+file = spec_ex.elf
+
[firq-linear-cpu-ids-kvm]
file = firq.elf
timeout = 20
--
2.36.1
