1 files changed, 141 insertions, 0 deletions
diff --git a/arch/s390/hypfs/hypfs_vm.c b/arch/s390/hypfs/hypfs_vm.c
new file mode 100644
index 000000000..3db40ad85
--- /dev/null
+++ b/arch/s390/hypfs/hypfs_vm.c
@@ -0,0 +1,141 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *    Hypervisor filesystem for Linux on s390. z/VM implementation.
+ *
+ *    Copyright IBM Corp. 2006
+ *    Author(s): Michael Holzheu <holzheu@de.ibm.com>
+ */
+
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/vmalloc.h>
+#include <asm/extable.h>
+#include <asm/diag.h>
+#include <asm/ebcdic.h>
+#include <asm/timex.h>
+#include "hypfs_vm.h"
+#include "hypfs.h"
+
+#define DBFS_D2FC_HDR_VERSION 0
+
+static char local_guest[] = "        ";
+static char all_guests[] = "*       ";
+static char *all_groups = all_guests;
+char *diag2fc_guest_query;
+
+static int diag2fc(int size, char* query, void *addr)
+{
+	unsigned long residual_cnt;
+	unsigned long rc;
+	struct diag2fc_parm_list parm_list;
+
+	memcpy(parm_list.userid, query, DIAG2FC_NAME_LEN);
+	ASCEBC(parm_list.userid, DIAG2FC_NAME_LEN);
+	memcpy(parm_list.aci_grp, all_groups, DIAG2FC_NAME_LEN);
+	ASCEBC(parm_list.aci_grp, DIAG2FC_NAME_LEN);
+	parm_list.addr = (unsigned long)addr;
+	parm_list.size = size;
+	parm_list.fmt = 0x02;
+	rc = -1;
+
+	diag_stat_inc(DIAG_STAT_X2FC);
+	asm volatile(
+		"	diag    %0,%1,0x2fc\n"
+		"0:	nopr	%%r7\n"
+		EX_TABLE(0b,0b)
+		: "=d" (residual_cnt), "+d" (rc) : "0" (&parm_list) : "memory");
+
+	if ((rc != 0 ) && (rc != -2))
+		return rc;
+	else
+		return -residual_cnt;
+}
+
+/*
+ * Allocate buffer for "query" and store diag 2fc at "offset"
+ */
+void *diag2fc_store(char *query, unsigned int *count, int offset)
+{
+	void *data;
+	int size;
+
+	do {
+		size = diag2fc(0, query, NULL);
+		if (size < 0)
+			return ERR_PTR(-EACCES);
+		data = vmalloc(size + offset);
+		if (!data)
+			return ERR_PTR(-ENOMEM);
+		if (diag2fc(size, query, data + offset) == 0)
+			break;
+		vfree(data);
+	} while (1);
+	*count = (size / sizeof(struct diag2fc_data));
+
+	return data;
+}
+
+void diag2fc_free(const void *data)
+{
+	vfree(data);
+}
+
+struct dbfs_d2fc_hdr {
+	u64	len;		/* Length of d2fc buffer without header */
+	u16	version;	/* Version of header */
+	union tod_clock tod_ext; /* TOD clock for d2fc */
+	u64	count;		/* Number of VM guests in d2fc buffer */
+	char	reserved[30];
+} __attribute__ ((packed));
+
+struct dbfs_d2fc {
+	struct dbfs_d2fc_hdr	hdr;	/* 64 byte header */
+	char			buf[];	/* d2fc buffer */
+} __attribute__ ((packed));
+
+static int dbfs_diag2fc_create(void **data, void **data_free_ptr, size_t *size)
+{
+	struct dbfs_d2fc *d2fc;
+	unsigned int count;
+
+	d2fc = diag2fc_store(diag2fc_guest_query, &count, sizeof(d2fc->hdr));
+	if (IS_ERR(d2fc))
+		return PTR_ERR(d2fc);
+	store_tod_clock_ext(&d2fc->hdr.tod_ext);
+	d2fc->hdr.len = count * sizeof(struct diag2fc_data);
+	d2fc->hdr.version = DBFS_D2FC_HDR_VERSION;
+	d2fc->hdr.count = count;
+	memset(&d2fc->hdr.reserved, 0, sizeof(d2fc->hdr.reserved));
+	*data = d2fc;
+	*data_free_ptr = d2fc;
+	*size = d2fc->hdr.len + sizeof(struct dbfs_d2fc_hdr);
+	return 0;
+}
+
+static struct hypfs_dbfs_file dbfs_file_2fc = {
+	.name		= "diag_2fc",
+	.data_create	= dbfs_diag2fc_create,
+	.data_free	= diag2fc_free,
+};
+
+int hypfs_vm_init(void)
+{
+	if (!MACHINE_IS_VM)
+		return 0;
+	if (diag2fc(0, all_guests, NULL) > 0)
+		diag2fc_guest_query = all_guests;
+	else if (diag2fc(0, local_guest, NULL) > 0)
+		diag2fc_guest_query = local_guest;
+	else
+		return -EACCES;
+	hypfs_dbfs_create_file(&dbfs_file_2fc);
+	return 0;
+}
+
+void hypfs_vm_exit(void)
+{
+	if (!MACHINE_IS_VM)
+		return;
+	hypfs_dbfs_remove_file(&dbfs_file_2fc);
+}