[kvm-unit-tests GIT PULL v2 11/14] s390x: Add tests for execute-type instructions

Nico Boehr
2023-04-04T11:37:22Z

From: Nina Schoetterl-Glausch <nsg@linux.ibm.com>

Test the instruction address used by targets of an execute instruction.
When the target instruction calculates a relative address, the result is
relative to the target instruction, not the execute instruction.

Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Nina Schoetterl-Glausch <nsg@linux.ibm.com>
Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Link: https://lore.kernel.org/r/20230317112339.774659-1-nsg@linux.ibm.com
Signed-off-by: Nico Boehr <nrb@linux.ibm.com>
---
s390x/Makefile | 1 +
s390x/ex.c | 188 ++++++++++++++++++++++++++++++++++++++++++++
s390x/unittests.cfg | 3 +
.gitlab-ci.yml | 1 +
4 files changed, 193 insertions(+)
create mode 100644 s390x/ex.c

diff --git a/s390x/Makefile b/s390x/Makefile
index ab146eb..a80db53 100644
--- a/s390x/Makefile
+++ b/s390x/Makefile
@@ -39,6 +39,7 @@ tests += $(TEST_DIR)/panic-loop-extint.elf
tests += $(TEST_DIR)/panic-loop-pgm.elf
tests += $(TEST_DIR)/migration-sck.elf
tests += $(TEST_DIR)/exittime.elf
+tests += $(TEST_DIR)/ex.elf

pv-tests += $(TEST_DIR)/pv-diags.elf

diff --git a/s390x/ex.c b/s390x/ex.c
new file mode 100644
index 0000000..dbd8030
--- /dev/null
+++ b/s390x/ex.c
@@ -0,0 +1,188 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright IBM Corp. 2023
+ *
+ * Test EXECUTE (RELATIVE LONG).
+ * These instructions execute a target instruction. The target instruction is formed
+ * by reading an instruction from memory and optionally modifying some of its bits.
+ * The execution of the target instruction is the same as if it was executed
+ * normally as part of the instruction sequence, except for the instruction
+ * address and the instruction-length code.
+ */
+
+#include <libcflat.h>
+
+/*
+ * Accesses to the operand of execute-type instructions are instruction fetches.
+ * Minimum alignment is two, since the relative offset is specified by number of halfwords.
+ */
+asm ( ".pushsection .text.exrl_targets,\"x\"\n"
+" .balign 2\n"
+" .popsection\n"
+);
+
+/*
+ * BRANCH AND SAVE, register register variant.
+ * Saves the next instruction address (address from PSW + length of instruction)
+ * to the first register. No branch is taken in this test, because 0 is
+ * specified as target.
+ * BASR does *not* perform a relative address calculation with an intermediate.
+ */
+static void test_basr(void)
+{
+ uint64_t ret_addr, after_ex;
+
+ report_prefix_push("BASR");
+ asm volatile ( ".pushsection .text.exrl_targets\n"
+ "0: basr %[ret_addr],0\n"
+ " .popsection\n"
+
+ " larl %[after_ex],1f\n"
+ " exrl 0,0b\n"
+ "1:\n"
+ : [ret_addr] "=d" (ret_addr),
+ [after_ex] "=d" (after_ex)
+ );
+
+ report(ret_addr == after_ex, "return address after EX");
+ report_prefix_pop();
+}
+
+/*
+ * BRANCH RELATIVE AND SAVE.
+ * According to PoP (Branch-Address Generation), the address calculated relative
+ * to the instruction address is relative to BRAS when it is the target of an
+ * execute-type instruction, not relative to the execute-type instruction.
+ */
+static void test_bras(void)
+{
+ uint64_t after_target, ret_addr, after_ex, branch_addr;
+
+ report_prefix_push("BRAS");
+ asm volatile ( ".pushsection .text.exrl_targets\n"
+ "0: bras %[ret_addr],1f\n"
+ " nopr %%r7\n"
+ "1: larl %[branch_addr],0\n"
+ " j 4f\n"
+ " .popsection\n"
+
+ " larl %[after_target],1b\n"
+ " larl %[after_ex],3f\n"
+ "2: exrl 0,0b\n"
+/*
+ * In case the address calculation is correct, we jump by the relative offset 1b-0b from 0b to 1b.
+ * In case the address calculation is relative to the exrl (i.e. a test failure),
+ * put a valid instruction at the same relative offset from the exrl, so the test continues in a
+ * controlled manner.
+ */
+ "3: larl %[branch_addr],0\n"
+ "4:\n"
+
+ " .if (1b - 0b) != (3b - 2b)\n"
+ " .error \"right and wrong target must have same offset\"\n"
+ " .endif\n"
+ : [after_target] "=d" (after_target),
+ [ret_addr] "=d" (ret_addr),
+ [after_ex] "=d" (after_ex),
+ [branch_addr] "=d" (branch_addr)
+ );
+
+ report(after_target == branch_addr, "address calculated relative to BRAS");
+ report(ret_addr == after_ex, "return address after EX");
+ report_prefix_pop();
+}
+
+/*
+ * LOAD ADDRESS RELATIVE LONG.
+ * If it is the target of an execute-type instruction, the address is relative
+ * to the LARL.
+ */
+static void test_larl(void)
+{
+ uint64_t target, addr;
+
+ report_prefix_push("LARL");
+ asm volatile ( ".pushsection .text.exrl_targets\n"
+ "0: larl %[addr],0\n"
+ " .popsection\n"
+
+ " larl %[target],0b\n"
+ " exrl 0,0b\n"
+ : [target] "=d" (target),
+ [addr] "=d" (addr)
+ );
+
+ report(target == addr, "address calculated relative to LARL");
+ report_prefix_pop();
+}
+
+/* LOAD LOGICAL RELATIVE LONG.
+ * If it is the target of an execute-type instruction, the address is relative
+ * to the LLGFRL.
+ */
+static void test_llgfrl(void)
+{
+ uint64_t target, value;
+
+ report_prefix_push("LLGFRL");
+ asm volatile ( ".pushsection .text.exrl_targets\n"
+ " .balign 4\n"
+ //operand of llgfrl must be word aligned
+ "0: llgfrl %[value],0\n"
+ " .popsection\n"
+
+ " llgfrl %[target],0b\n"
+ //align (pad with nop), in case the wrong operand is used
+ " .balignw 4,0x0707\n"
+ " exrl 0,0b\n"
+ : [target] "=d" (target),
+ [value] "=d" (value)
+ );
+
+ report(target == value, "loaded correct value");
+ report_prefix_pop();
+}
+
+/*
+ * COMPARE RELATIVE LONG
+ * If it is the target of an execute-type instruction, the address is relative
+ * to the CRL.
+ */
+static void test_crl(void)
+{
+ uint32_t program_mask, cc, crl_word;
+
+ report_prefix_push("CRL");
+ asm volatile ( ".pushsection .text.exrl_targets\n"
+ //operand of crl must be word aligned
+ " .balign 4\n"
+ "0: crl %[crl_word],0\n"
+ " .popsection\n"
+
+ " lrl %[crl_word],0b\n"
+ //align (pad with nop), in case the wrong operand is used
+ " .balignw 4,0x0707\n"
+ " exrl 0,0b\n"
+ " ipm %[program_mask]\n"
+ : [program_mask] "=d" (program_mask),
+ [crl_word] "=d" (crl_word)
+ :: "cc"
+ );
+
+ cc = program_mask >> 28;
+ report(!cc, "operand compared to is relative to CRL");
+ report_prefix_pop();
+}
+
+int main(int argc, char **argv)
+{
+ report_prefix_push("ex");
+ test_basr();
+ test_bras();
+ test_larl();
+ test_llgfrl();
+ test_crl();
+ report_prefix_pop();
+
+ return report_summary();
+}
diff --git a/s390x/unittests.cfg b/s390x/unittests.cfg
index d97eb5e..b61faf0 100644
--- a/s390x/unittests.cfg
+++ b/s390x/unittests.cfg
@@ -215,3 +215,6 @@ file = migration-skey.elf
smp = 2
groups = migration
extra_params = -append '--parallel'
+
+[execute]
+file = ex.elf
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index ad7949c..a999f64 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -275,6 +275,7 @@ s390x-kvm:
- ACCEL=kvm ./run_tests.sh
selftest-setup intercept emulator sieve sthyi diag10 diag308 pfmf
cmm vector gs iep cpumodel diag288 stsi sclp-1g sclp-3g css skrf sie
+ execute
| tee results.txt
- grep -q PASS results.txt && ! grep -q FAIL results.txt
only:
--
2.39.2