[kvm-unit-tests PATCH v2 2/3] lib: s390x: snippet.h: Add a few constants that will make our life easier

[Janosch Frank <frankja@linux.ibm.com>]

The variable names for the snippet objects are of gigantic length so
let's define a few macros to make them easier to read.

Also add a standard PSW which should be used to start the snippet.

Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
---
 lib/s390x/snippet.h | 34 ++++++++++++++++++++++++++++++++++
 s390x/mvpg-sie.c    | 13 ++++++-------
 2 files changed, 40 insertions(+), 7 deletions(-)
 create mode 100644 lib/s390x/snippet.h

diff --git a/lib/s390x/snippet.h b/lib/s390x/snippet.h
new file mode 100644
index 00000000..8e4765f8
--- /dev/null
+++ b/lib/s390x/snippet.h
@@ -0,0 +1,34 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Snippet definitions
+ *
+ * Copyright IBM Corp. 2021
+ * Author: Janosch Frank <frankja@linux.ibm.com>
+ */
+
+#ifndef _S390X_SNIPPET_H_
+#define _S390X_SNIPPET_H_
+
+/* This macro cuts down the length of the pointers to snippets */
+#define SNIPPET_NAME_START(type, file) \
+	_binary_s390x_snippets_##type##_##file##_gbin_start
+#define SNIPPET_NAME_END(type, file) \
+	_binary_s390x_snippets_##type##_##file##_gbin_end
+
+/* Returns the length of the snippet */
+#define SNIPPET_LEN(type, file) \
+	((uintptr_t)SNIPPET_NAME_END(type, file) - (uintptr_t)SNIPPET_NAME_START(type, file))
+
+/*
+ * C snippet instructions start at 0x4000 due to the prefix and the
+ * stack being before that. ASM snippets don't strictly need a stack
+ * but keeping the starting address the same means less code.
+ */
+#define SNIPPET_ENTRY_ADDR 0x4000
+
+/* Standard entry PSWs for snippets which can simply be copied into the guest PSW */
+static const struct psw snippet_psw = {
+	.mask = PSW_MASK_64,
+	.addr = SNIPPET_ENTRY_ADDR,
+};
+#endif
diff --git a/s390x/mvpg-sie.c b/s390x/mvpg-sie.c
index 5adcec1e..d526069d 100644
--- a/s390x/mvpg-sie.c
+++ b/s390x/mvpg-sie.c
@@ -19,6 +19,7 @@
 #include <vm.h>
 #include <sclp.h>
 #include <sie.h>
+#include <snippet.h>
 
 static u8 *guest;
 static struct vm vm;
@@ -27,8 +28,8 @@ static uint8_t *src;
 static uint8_t *dst;
 static uint8_t *cmp;
 
-extern const char _binary_s390x_snippets_c_mvpg_snippet_gbin_start[];
-extern const char _binary_s390x_snippets_c_mvpg_snippet_gbin_end[];
+extern const char SNIPPET_NAME_START(c, mvpg_snippet)[];
+extern const char SNIPPET_NAME_END(c, mvpg_snippet)[];
 int binary_size;
 
 static void test_mvpg_pei(void)
@@ -77,10 +78,9 @@ static void test_mvpg_pei(void)
 
 static void test_mvpg(void)
 {
-	int binary_size = ((uintptr_t)_binary_s390x_snippets_c_mvpg_snippet_gbin_end -
-			   (uintptr_t)_binary_s390x_snippets_c_mvpg_snippet_gbin_start);
+	int binary_size = SNIPPET_LEN(c, mvpg_snippet);
 
-	memcpy(guest, _binary_s390x_snippets_c_mvpg_snippet_gbin_start, binary_size);
+	memcpy(guest, SNIPPET_NAME_START(c, mvpg_snippet), binary_size);
 	memset(src, 0x42, PAGE_SIZE);
 	memset(dst, 0x43, PAGE_SIZE);
 	sie(&vm);
@@ -96,8 +96,7 @@ static void setup_guest(void)
 
 	sie_guest_create(&vm, (uint64_t)guest, HPAGE_SIZE);
 
-	vm.sblk->gpsw.addr = PAGE_SIZE * 4;
-	vm.sblk->gpsw.mask = PSW_MASK_64;
+	vm.sblk->gpsw = snippet_psw;
 	vm.sblk->ictl = ICTL_OPEREXC | ICTL_PINT;
 	/* Enable MVPG interpretation as we want to test KVM and not ourselves */
 	vm.sblk->eca = ECA_MVPGI;
-- 
2.30.2