By adding a load reset routine to cstart.S we can also test the clear
reset done by subcode 0, as we now can restore our registers again.
Signed-off-by: Janosch Frank <frankja@xxxxxxxxxxxxx>
---
I managed to extract this from another bigger test, so let's add it to the bunch.
I'd be very happy about assembly review :-)
---
s390x/cstart64.S | 27 +++++++++++++++++++++++++++
s390x/diag308.c | 31 ++++++++++---------------------
2 files changed, 37 insertions(+), 21 deletions(-)
diff --git a/s390x/cstart64.S b/s390x/cstart64.S
index dedfe80..47045e1 100644
--- a/s390x/cstart64.S
+++ b/s390x/cstart64.S
@@ -145,6 +145,33 @@ memsetxc:
.endm
.section .text
+/*
+ * load_reset calling convention:
+ * %r2 subcode (0 or 1)
+ */
+.globl load_reset
+load_reset:
+ SAVE_REGS
+ /* Save the first PSW word to the IPL PSW */
+ epsw %r0, %r1
+ st %r0, 0
+ /* Store the address and the bit for 31 bit addressing */
+ larl %r0, 0f
+ oilh %r0, 0x8000
+ st %r0, 0x4
+ /* Do the reset */
+ diag %r0,%r2,0x308
+ /* Failure path */
+ xgr %r2, %r2
+ br %r14
+ /* Success path */
+ /* We lost cr0 due to the reset */
+0: larl %r1, initial_cr0
+ lctlg %c0, %c0, 0(%r1)
+ RESTORE_REGS
+ lhi %r2, 1
+ br %r14
+
pgm_int:
SAVE_REGS
brasl %r14, handle_pgm_int
diff --git a/s390x/diag308.c b/s390x/diag308.c
index f085b1a..baf9fd3 100644
--- a/s390x/diag308.c
+++ b/s390x/diag308.c
@@ -21,32 +21,20 @@ static void test_priv(void)
check_pgm_int_code(PGM_INT_CODE_PRIVILEGED_OPERATION);
}
+
/*
- * Check that diag308 with subcode 1 loads the PSW at address 0, i.e.
+ * Check that diag308 with subcode 0 and 1 loads the PSW at address 0, i.e.
* that we can put a pointer into address 4 which then gets executed.
*/
+extern int load_reset(u64);
+static void test_subcode0(void)
+{
+ report("load modified clear done", load_reset(0));
+}
+
static void test_subcode1(void)
{
- uint64_t saved_psw = *(uint64_t *)0;
- long subcode = 1;
- long ret, tmp;
-
- asm volatile (
- " epsw %0,%1\n"
- " st %0,0\n"
- " larl %0,0f\n"
- " oilh %0,0x8000\n"
- " st %0,4\n"
- " diag 0,%2,0x308\n"
- " lghi %0,0\n"
- " j 1f\n"
- "0: lghi %0,1\n"
- "1:"
- : "=&d"(ret), "=&d"(tmp) : "d"(subcode) : "memory");
-
- *(uint64_t *)0 = saved_psw;
-
- report("load normal reset done", ret == 1);
+ report("load normal reset done", load_reset(1));
}
/* Expect a specification exception when using an uneven register */
@@ -107,6 +95,7 @@ static struct {
void (*func)(void);
} tests[] = {
{ "privileged", test_priv },
+ { "subcode 0", test_subcode0 },
{ "subcode 1", test_subcode1 },
{ "subcode 5", test_subcode5 },
{ "subcode 6", test_subcode6 },
--
2.17.0
