[kvm-unit-tests PATCH v2 3/3] s390x/spec_ex: Add test of EXECUTE with odd target address

[Nina Schoetterl-Glausch <nsg@xxxxxxxxxxxxx>]

The EXECUTE instruction executes the instruction at the given target
address. This address must be halfword aligned, otherwise a
specification exception occurs.
Add a test for this.

Signed-off-by: Nina Schoetterl-Glausch <nsg@xxxxxxxxxxxxx>
---
 s390x/spec_ex.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/s390x/spec_ex.c b/s390x/spec_ex.c
index a26c56aa..dd097f9b 100644
--- a/s390x/spec_ex.c
+++ b/s390x/spec_ex.c
@@ -177,6 +177,30 @@ static int short_psw_bit_12_is_0(void)
 	return 0;
 }
 
+static int odd_ex_target(void)
+{
+	uint64_t pre_target_addr;
+	int to = 0, from = 0x0dd;
+
+	asm volatile ( ".pushsection .rodata\n"
+		"pre_odd_ex_target:\n"
+		"	.balign	2\n"
+		"	. = . + 1\n"
+		"	lr	%[to],%[from]\n"
+		"	.popsection\n"
+
+		"	larl	%[pre_target_addr],pre_odd_ex_target\n"
+		"	ex	0,1(%[pre_target_addr])\n"
+		: [pre_target_addr] "=&a" (pre_target_addr),
+		  [to] "+d" (to)
+		: [from] "d" (from)
+	);
+
+	assert((pre_target_addr + 1) & 1);
+	report(to != from, "did not perform ex with odd target");
+	return 0;
+}
+
 static int bad_alignment(void)
 {
 	uint32_t words[5] __attribute__((aligned(16)));
@@ -218,6 +242,7 @@ static const struct spec_ex_trigger spec_ex_triggers[] = {
 	{ "psw_bit_12_is_1", &psw_bit_12_is_1, false, &fixup_invalid_psw },
 	{ "short_psw_bit_12_is_0", &short_psw_bit_12_is_0, false, &fixup_invalid_psw },
 	{ "psw_odd_address", &psw_odd_address, false, &fixup_invalid_psw },
+	{ "odd_ex_target", &odd_ex_target, true, NULL },
 	{ "bad_alignment", &bad_alignment, true, NULL },
 	{ "not_even", &not_even, true, NULL },
 	{ NULL, NULL, false, NULL },
-- 
2.36.1