Release 4.18 drivers/s390/char/vmcp.c
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright IBM Corp. 2004, 2010
* Interface implementation for communication with the z/VM control program
*
* Author(s): Christian Borntraeger <borntraeger@de.ibm.com>
*
* z/VMs CP offers the possibility to issue commands via the diagnose code 8
* this driver implements a character device that issues these commands and
* returns the answer of CP.
*
* The idea of this driver is based on cpint from Neale Ferguson and #CP in CMS
*/
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/compat.h>
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/export.h>
#include <linux/mutex.h>
#include <linux/cma.h>
#include <linux/mm.h>
#include <asm/cpcmd.h>
#include <asm/debug.h>
#include <asm/vmcp.h>
struct vmcp_session {
char *response;
unsigned int bufsize;
unsigned int cma_alloc : 1;
int resp_size;
int resp_code;
struct mutex mutex;
};
static debug_info_t *vmcp_debug;
static unsigned long vmcp_cma_size __initdata = CONFIG_VMCP_CMA_SIZE * 1024 * 1024;
static struct cma *vmcp_cma;
static int __init early_parse_vmcp_cma(char *p)
{
vmcp_cma_size = ALIGN(memparse(p, NULL), PAGE_SIZE);
return 0;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Heiko Carstens | 28 | 100.00% | 1 | 100.00% |
| Total | 28 | 100.00% | 1 | 100.00% |
early_param("vmcp_cma", early_parse_vmcp_cma);
void __init vmcp_cma_reserve(void)
{
if (!MACHINE_IS_VM)
return;
cma_declare_contiguous(0, vmcp_cma_size, 0, 0, 0, false, "vmcp", &vmcp_cma);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Heiko Carstens | 34 | 100.00% | 1 | 100.00% |
| Total | 34 | 100.00% | 1 | 100.00% |
static void vmcp_response_alloc(struct vmcp_session *session)
{
struct page *page = NULL;
int nr_pages, order;
order = get_order(session->bufsize);
nr_pages = ALIGN(session->bufsize, PAGE_SIZE) >> PAGE_SHIFT;
/*
* For anything below order 3 allocations rely on the buddy
* allocator. If such low-order allocations can't be handled
* anymore the system won't work anyway.
*/
if (order > 2)
page = cma_alloc(vmcp_cma, nr_pages, 0, GFP_KERNEL);
if (page) {
session->response = (char *)page_to_phys(page);
session->cma_alloc = 1;
return;
}
session->response = (char *)__get_free_pages(GFP_KERNEL | __GFP_RETRY_MAYFAIL, order);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Heiko Carstens | 108 | 100.00% | 1 | 100.00% |
| Total | 108 | 100.00% | 1 | 100.00% |
static void vmcp_response_free(struct vmcp_session *session)
{
int nr_pages, order;
struct page *page;
if (!session->response)
return;
order = get_order(session->bufsize);
nr_pages = ALIGN(session->bufsize, PAGE_SIZE) >> PAGE_SHIFT;
if (session->cma_alloc) {
page = phys_to_page((unsigned long)session->response);
cma_release(vmcp_cma, page, nr_pages);
session->cma_alloc = 0;
} else {
free_pages((unsigned long)session->response, order);
}
session->response = NULL;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Heiko Carstens | 109 | 100.00% | 2 | 100.00% |
| Total | 109 | 100.00% | 2 | 100.00% |
static int vmcp_open(struct inode *inode, struct file *file)
{
struct vmcp_session *session;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
session = kmalloc(sizeof(*session), GFP_KERNEL);
if (!session)
return -ENOMEM;
session->bufsize = PAGE_SIZE;
session->response = NULL;
session->resp_size = 0;
mutex_init(&session->mutex);
file->private_data = session;
return nonseekable_open(inode, file);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Christian Bornträger | 95 | 100.00% | 2 | 100.00% |
| Total | 95 | 100.00% | 2 | 100.00% |
static int vmcp_release(struct inode *inode, struct file *file)
{
struct vmcp_session *session;
session = file->private_data;
file->private_data = NULL;
vmcp_response_free(session);
kfree(session);
return 0;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Christian Bornträger | 45 | 97.83% | 1 | 50.00% |
| Heiko Carstens | 1 | 2.17% | 1 | 50.00% |
| Total | 46 | 100.00% | 2 | 100.00% |
static ssize_t
vmcp_read(struct file *file, char __user *buff, size_t count, loff_t *ppos)
{
ssize_t ret;
size_t size;
struct vmcp_session *session;
session = file->private_data;
if (mutex_lock_interruptible(&session->mutex))
return -ERESTARTSYS;
if (!session->response) {
mutex_unlock(&session->mutex);
return 0;
}
size = min_t(size_t, session->resp_size, session->bufsize);
ret = simple_read_from_buffer(buff, count, ppos,
session->response, size);
mutex_unlock(&session->mutex);
return ret;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Christian Bornträger | 100 | 85.47% | 2 | 66.67% |
| Akinobu Mita | 17 | 14.53% | 1 | 33.33% |
| Total | 117 | 100.00% | 3 | 100.00% |
static ssize_t
vmcp_write(struct file *file, const char __user *buff, size_t count,
loff_t *ppos)
{
char *cmd;
struct vmcp_session *session;
if (count > 240)
return -EINVAL;
cmd = memdup_user_nul(buff, count);
if (IS_ERR(cmd))
return PTR_ERR(cmd);
session = file->private_data;
if (mutex_lock_interruptible(&session->mutex)) {
kfree(cmd);
return -ERESTARTSYS;
}
if (!session->response)
vmcp_response_alloc(session);
if (!session->response) {
mutex_unlock(&session->mutex);
kfree(cmd);
return -ENOMEM;
}
debug_text_event(vmcp_debug, 1, cmd);
session->resp_size = cpcmd(cmd, session->response, session->bufsize,
&session->resp_code);
mutex_unlock(&session->mutex);
kfree(cmd);
*ppos = 0; /* reset the file pointer after a command */
return count;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Christian Bornträger | 176 | 96.17% | 4 | 66.67% |
| Al Viro | 6 | 3.28% | 1 | 16.67% |
| Heiko Carstens | 1 | 0.55% | 1 | 16.67% |
| Total | 183 | 100.00% | 6 | 100.00% |
/*
* These ioctls are available, as the semantics of the diagnose 8 call
* does not fit very well into a Linux call. Diagnose X'08' is described in
* CP Programming Services SC24-6084-00
*
* VMCP_GETCODE: gives the CP return code back to user space
* VMCP_SETBUF: sets the response buffer for the next write call. diagnose 8
* expects adjacent pages in real storage and to make matters worse, we
* dont know the size of the response. Therefore we default to PAGESIZE and
* let userspace to change the response size, if userspace expects a bigger
* response
*/
static long vmcp_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
struct vmcp_session *session;
int ret = -ENOTTY;
int __user *argp;
session = file->private_data;
if (is_compat_task())
argp = compat_ptr(arg);
else
argp = (int __user *)arg;
if (mutex_lock_interruptible(&session->mutex))
return -ERESTARTSYS;
switch (cmd) {
case VMCP_GETCODE:
ret = put_user(session->resp_code, argp);
break;
case VMCP_SETBUF:
vmcp_response_free(session);
ret = get_user(session->bufsize, argp);
if (ret)
session->bufsize = PAGE_SIZE;
if (!session->bufsize || get_order(session->bufsize) > 8) {
session->bufsize = PAGE_SIZE;
ret = -EINVAL;
}
break;
case VMCP_GETSIZE:
ret = put_user(session->resp_size, argp);
break;
default:
break;
}
mutex_unlock(&session->mutex);
return ret;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Christian Bornträger | 118 | 63.78% | 2 | 33.33% |
| Heiko Carstens | 67 | 36.22% | 4 | 66.67% |
| Total | 185 | 100.00% | 6 | 100.00% |
static const struct file_operations vmcp_fops = {
.owner = THIS_MODULE,
.open = vmcp_open,
.release = vmcp_release,
.read = vmcp_read,
.write = vmcp_write,
.unlocked_ioctl = vmcp_ioctl,
.compat_ioctl = vmcp_ioctl,
.llseek = no_llseek,
};
static struct miscdevice vmcp_dev = {
.name = "vmcp",
.minor = MISC_DYNAMIC_MINOR,
.fops = &vmcp_fops,
};
static int __init vmcp_init(void)
{
int ret;
if (!MACHINE_IS_VM)
return 0;
vmcp_debug = debug_register("vmcp", 1, 1, 240);
if (!vmcp_debug)
return -ENOMEM;
ret = debug_register_view(vmcp_debug, &debug_hex_ascii_view);
if (ret) {
debug_unregister(vmcp_debug);
return ret;
}
ret = misc_register(&vmcp_dev);
if (ret)
debug_unregister(vmcp_debug);
return ret;
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Christian Bornträger | 85 | 98.84% | 2 | 66.67% |
| Heiko Carstens | 1 | 1.16% | 1 | 33.33% |
| Total | 86 | 100.00% | 3 | 100.00% |
device_initcall(vmcp_init);
Overall Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Christian Bornträger | 714 | 60.97% | 4 | 20.00% |
| Heiko Carstens | 424 | 36.21% | 10 | 50.00% |
| Akinobu Mita | 17 | 1.45% | 1 | 5.00% |
| Al Viro | 6 | 0.51% | 1 | 5.00% |
| Arnd Bergmann | 5 | 0.43% | 1 | 5.00% |
| Tejun Heo | 3 | 0.26% | 1 | 5.00% |
| Arjan van de Ven | 1 | 0.09% | 1 | 5.00% |
| Greg Kroah-Hartman | 1 | 0.09% | 1 | 5.00% |
| Total | 1171 | 100.00% | 20 | 100.00% |
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