linux/arch/s390/hypfs/hypfs_sprp.c
Martin Schwidefsky 07be038209 s390/hypfs: add interface for diagnose 0x304
To provide access to the set-partition-resource-parameter interface
to user space add a new attribute to hypfs/debugfs:
 * s390_hypsfs/diag_304
The data for the query-partition-resource-parameters command can
be access by a read on the attribute. All other diagnose 0x304
requests need to be submitted via ioctl with CAP_SYS_ADMIN rights.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2014-01-24 09:40:59 +01:00

142 lines
3.1 KiB
C

/*
* Hypervisor filesystem for Linux on s390.
* Set Partition-Resource Parameter interface.
*
* Copyright IBM Corp. 2013
* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
*/
#include <linux/compat.h>
#include <linux/errno.h>
#include <linux/gfp.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/uaccess.h>
#include <asm/compat.h>
#include <asm/sclp.h>
#include "hypfs.h"
#define DIAG304_SET_WEIGHTS 0
#define DIAG304_QUERY_PRP 1
#define DIAG304_SET_CAPPING 2
#define DIAG304_CMD_MAX 2
static unsigned long hypfs_sprp_diag304(void *data, unsigned long cmd)
{
register unsigned long _data asm("2") = (unsigned long) data;
register unsigned long _rc asm("3");
register unsigned long _cmd asm("4") = cmd;
asm volatile("diag %1,%2,0x304\n"
: "=d" (_rc) : "d" (_data), "d" (_cmd) : "memory");
return _rc;
}
static void hypfs_sprp_free(const void *data)
{
free_page((unsigned long) data);
}
static int hypfs_sprp_create(void **data_ptr, void **free_ptr, size_t *size)
{
unsigned long rc;
void *data;
data = (void *) get_zeroed_page(GFP_KERNEL);
if (!data)
return -ENOMEM;
rc = hypfs_sprp_diag304(data, DIAG304_QUERY_PRP);
if (rc != 1) {
*data_ptr = *free_ptr = NULL;
*size = 0;
free_page((unsigned long) data);
return -EIO;
}
*data_ptr = *free_ptr = data;
*size = PAGE_SIZE;
return 0;
}
static int __hypfs_sprp_ioctl(void __user *user_area)
{
struct hypfs_diag304 diag304;
unsigned long cmd;
void __user *udata;
void *data;
int rc;
if (copy_from_user(&diag304, user_area, sizeof(diag304)))
return -EFAULT;
if ((diag304.args[0] >> 8) != 0 || diag304.args[1] > DIAG304_CMD_MAX)
return -EINVAL;
data = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
if (!data)
return -ENOMEM;
udata = (void __user *)(unsigned long) diag304.data;
if (diag304.args[1] == DIAG304_SET_WEIGHTS ||
diag304.args[1] == DIAG304_SET_CAPPING)
if (copy_from_user(data, udata, PAGE_SIZE)) {
rc = -EFAULT;
goto out;
}
cmd = *(unsigned long *) &diag304.args[0];
diag304.rc = hypfs_sprp_diag304(data, cmd);
if (diag304.args[1] == DIAG304_QUERY_PRP)
if (copy_to_user(udata, data, PAGE_SIZE)) {
rc = -EFAULT;
goto out;
}
rc = copy_to_user(user_area, &diag304, sizeof(diag304)) ? -EFAULT : 0;
out:
free_page((unsigned long) data);
return rc;
}
static long hypfs_sprp_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
void __user *argp;
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
if (is_compat_task())
argp = compat_ptr(arg);
else
argp = (void __user *) arg;
switch (cmd) {
case HYPFS_DIAG304:
return __hypfs_sprp_ioctl(argp);
default: /* unknown ioctl number */
return -ENOTTY;
}
return 0;
}
static struct hypfs_dbfs_file hypfs_sprp_file = {
.name = "diag_304",
.data_create = hypfs_sprp_create,
.data_free = hypfs_sprp_free,
.unlocked_ioctl = hypfs_sprp_ioctl,
};
int hypfs_sprp_init(void)
{
if (!sclp_has_sprp())
return 0;
return hypfs_dbfs_create_file(&hypfs_sprp_file);
}
void hypfs_sprp_exit(void)
{
if (!sclp_has_sprp())
return;
hypfs_dbfs_remove_file(&hypfs_sprp_file);
}