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// 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(-ENOSYS);
}
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 = -ENOSYS;
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 ? -ENOSYS : 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);
}
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