1 files changed, 219 insertions, 0 deletions
diff --git a/arch/s390/hypfs/hypfs_diag.c b/arch/s390/hypfs/hypfs_diag.c
new file mode 100644
index 000000000..279b7bba4
--- /dev/null
+++ b/arch/s390/hypfs/hypfs_diag.c
@@ -0,0 +1,219 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *    Hypervisor filesystem for Linux on s390. Diag 204 and 224
+ *    implementation.
+ *
+ *    Copyright IBM Corp. 2006, 2008
+ *    Author(s): Michael Holzheu <holzheu@de.ibm.com>
+ */
+
+#define KMSG_COMPONENT "hypfs"
+#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
+
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/vmalloc.h>
+#include <linux/mm.h>
+#include <asm/diag.h>
+#include <asm/ebcdic.h>
+#include "hypfs_diag.h"
+#include "hypfs.h"
+
+#define DBFS_D204_HDR_VERSION	0
+
+static enum diag204_sc diag204_store_sc;	/* used subcode for store */
+static enum diag204_format diag204_info_type;	/* used diag 204 data format */
+
+static void *diag204_buf;		/* 4K aligned buffer for diag204 data */
+static int diag204_buf_pages;		/* number of pages for diag204 data */
+
+static struct dentry *dbfs_d204_file;
+
+enum diag204_format diag204_get_info_type(void)
+{
+	return diag204_info_type;
+}
+
+static void diag204_set_info_type(enum diag204_format type)
+{
+	diag204_info_type = type;
+}
+
+/* Diagnose 204 functions */
+/*
+ * For the old diag subcode 4 with simple data format we have to use real
+ * memory. If we use subcode 6 or 7 with extended data format, we can (and
+ * should) use vmalloc, since we need a lot of memory in that case. Currently
+ * up to 93 pages!
+ */
+
+static void diag204_free_buffer(void)
+{
+	vfree(diag204_buf);
+	diag204_buf = NULL;
+}
+
+void *diag204_get_buffer(enum diag204_format fmt, int *pages)
+{
+	if (diag204_buf) {
+		*pages = diag204_buf_pages;
+		return diag204_buf;
+	}
+	if (fmt == DIAG204_INFO_SIMPLE) {
+		*pages = 1;
+	} else {/* DIAG204_INFO_EXT */
+		*pages = diag204((unsigned long)DIAG204_SUBC_RSI |
+				 (unsigned long)DIAG204_INFO_EXT, 0, NULL);
+		if (*pages <= 0)
+			return ERR_PTR(-EOPNOTSUPP);
+	}
+	diag204_buf = __vmalloc_node(array_size(*pages, PAGE_SIZE),
+				     PAGE_SIZE, GFP_KERNEL, NUMA_NO_NODE,
+				     __builtin_return_address(0));
+	if (!diag204_buf)
+		return ERR_PTR(-ENOMEM);
+	diag204_buf_pages = *pages;
+	return diag204_buf;
+}
+
+/*
+ * diag204_probe() has to find out, which type of diagnose 204 implementation
+ * we have on our machine. Currently there are three possible scanarios:
+ *   - subcode 4   + simple data format (only one page)
+ *   - subcode 4-6 + extended data format
+ *   - subcode 4-7 + extended data format
+ *
+ * Subcode 5 is used to retrieve the size of the data, provided by subcodes
+ * 6 and 7. Subcode 7 basically has the same function as subcode 6. In addition
+ * to subcode 6 it provides also information about secondary cpus.
+ * In order to get as much information as possible, we first try
+ * subcode 7, then 6 and if both fail, we use subcode 4.
+ */
+
+static int diag204_probe(void)
+{
+	void *buf;
+	int pages, rc;
+
+	buf = diag204_get_buffer(DIAG204_INFO_EXT, &pages);
+	if (!IS_ERR(buf)) {
+		if (diag204((unsigned long)DIAG204_SUBC_STIB7 |
+			    (unsigned long)DIAG204_INFO_EXT, pages, buf) >= 0) {
+			diag204_store_sc = DIAG204_SUBC_STIB7;
+			diag204_set_info_type(DIAG204_INFO_EXT);
+			goto out;
+		}
+		if (diag204((unsigned long)DIAG204_SUBC_STIB6 |
+			    (unsigned long)DIAG204_INFO_EXT, pages, buf) >= 0) {
+			diag204_store_sc = DIAG204_SUBC_STIB6;
+			diag204_set_info_type(DIAG204_INFO_EXT);
+			goto out;
+		}
+		diag204_free_buffer();
+	}
+
+	/* subcodes 6 and 7 failed, now try subcode 4 */
+
+	buf = diag204_get_buffer(DIAG204_INFO_SIMPLE, &pages);
+	if (IS_ERR(buf)) {
+		rc = PTR_ERR(buf);
+		goto fail_alloc;
+	}
+	if (diag204((unsigned long)DIAG204_SUBC_STIB4 |
+		    (unsigned long)DIAG204_INFO_SIMPLE, pages, buf) >= 0) {
+		diag204_store_sc = DIAG204_SUBC_STIB4;
+		diag204_set_info_type(DIAG204_INFO_SIMPLE);
+		goto out;
+	} else {
+		rc = -EOPNOTSUPP;
+		goto fail_store;
+	}
+out:
+	rc = 0;
+fail_store:
+	diag204_free_buffer();
+fail_alloc:
+	return rc;
+}
+
+int diag204_store(void *buf, int pages)
+{
+	int rc;
+
+	rc = diag204((unsigned long)diag204_store_sc |
+		     (unsigned long)diag204_get_info_type(), pages, buf);
+	return rc < 0 ? -EOPNOTSUPP : 0;
+}
+
+struct dbfs_d204_hdr {
+	u64	len;		/* Length of d204 buffer without header */
+	u16	version;	/* Version of header */
+	u8	sc;		/* Used subcode */
+	char	reserved[53];
+} __attribute__ ((packed));
+
+struct dbfs_d204 {
+	struct dbfs_d204_hdr	hdr;	/* 64 byte header */
+	char			buf[];	/* d204 buffer */
+} __attribute__ ((packed));
+
+static int dbfs_d204_create(void **data, void **data_free_ptr, size_t *size)
+{
+	struct dbfs_d204 *d204;
+	int rc, buf_size;
+	void *base;
+
+	buf_size = PAGE_SIZE * (diag204_buf_pages + 1) + sizeof(d204->hdr);
+	base = vzalloc(buf_size);
+	if (!base)
+		return -ENOMEM;
+	d204 = PTR_ALIGN(base + sizeof(d204->hdr), PAGE_SIZE) - sizeof(d204->hdr);
+	rc = diag204_store(d204->buf, diag204_buf_pages);
+	if (rc) {
+		vfree(base);
+		return rc;
+	}
+	d204->hdr.version = DBFS_D204_HDR_VERSION;
+	d204->hdr.len = PAGE_SIZE * diag204_buf_pages;
+	d204->hdr.sc = diag204_store_sc;
+	*data = d204;
+	*data_free_ptr = base;
+	*size = d204->hdr.len + sizeof(struct dbfs_d204_hdr);
+	return 0;
+}
+
+static struct hypfs_dbfs_file dbfs_file_d204 = {
+	.name		= "diag_204",
+	.data_create	= dbfs_d204_create,
+	.data_free	= vfree,
+};
+
+__init int hypfs_diag_init(void)
+{
+	int rc;
+
+	if (diag204_probe()) {
+		pr_info("The hardware system does not support hypfs\n");
+		return -ENODATA;
+	}
+
+	if (diag204_get_info_type() == DIAG204_INFO_EXT)
+		hypfs_dbfs_create_file(&dbfs_file_d204);
+
+	rc = hypfs_diag_fs_init();
+	if (rc) {
+		pr_err("The hardware system does not provide all functions required by hypfs\n");
+		debugfs_remove(dbfs_d204_file);
+	}
+	return rc;
+}
+
+void hypfs_diag_exit(void)
+{
+	debugfs_remove(dbfs_d204_file);
+	hypfs_diag_fs_exit();
+	diag204_free_buffer();
+	hypfs_dbfs_remove_file(&dbfs_file_d204);
+}