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// SPDX-License-Identifier: GPL-2.0
/*
* Privileged ADI driver for sparc64
*
* Author: Tom Hromatka <tom.hromatka@oracle.com>
*/
#include <linux/kernel.h>
#include <linux/miscdevice.h>
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <asm/asi.h>
#define MAX_BUF_SZ PAGE_SIZE
static int adi_open(struct inode *inode, struct file *file)
{
file->f_mode |= FMODE_UNSIGNED_OFFSET;
return 0;
}
static int read_mcd_tag(unsigned long addr)
{
long err;
int ver;
__asm__ __volatile__(
"1: ldxa [%[addr]] %[asi], %[ver]\n"
" mov 0, %[err]\n"
"2:\n"
" .section .fixup,#alloc,#execinstr\n"
" .align 4\n"
"3: sethi %%hi(2b), %%g1\n"
" jmpl %%g1 + %%lo(2b), %%g0\n"
" mov %[invalid], %[err]\n"
" .previous\n"
" .section __ex_table, \"a\"\n"
" .align 4\n"
" .word 1b, 3b\n"
" .previous\n"
: [ver] "=r" (ver), [err] "=r" (err)
: [addr] "r" (addr), [invalid] "i" (EFAULT),
[asi] "i" (ASI_MCD_REAL)
: "memory", "g1"
);
if (err)
return -EFAULT;
else
return ver;
}
static ssize_t adi_read(struct file *file, char __user *buf,
size_t count, loff_t *offp)
{
size_t ver_buf_sz, bytes_read = 0;
int ver_buf_idx = 0;
loff_t offset;
u8 *ver_buf;
ssize_t ret;
ver_buf_sz = min_t(size_t, count, MAX_BUF_SZ);
ver_buf = kmalloc(ver_buf_sz, GFP_KERNEL);
if (!ver_buf)
return -ENOMEM;
offset = (*offp) * adi_blksize();
while (bytes_read < count) {
ret = read_mcd_tag(offset);
if (ret < 0)
goto out;
ver_buf[ver_buf_idx] = (u8)ret;
ver_buf_idx++;
offset += adi_blksize();
if (ver_buf_idx >= ver_buf_sz) {
if (copy_to_user(buf + bytes_read, ver_buf,
ver_buf_sz)) {
ret = -EFAULT;
goto out;
}
bytes_read += ver_buf_sz;
ver_buf_idx = 0;
ver_buf_sz = min(count - bytes_read,
(size_t)MAX_BUF_SZ);
}
}
(*offp) += bytes_read;
ret = bytes_read;
out:
kfree(ver_buf);
return ret;
}
static int set_mcd_tag(unsigned long addr, u8 ver)
{
long err;
__asm__ __volatile__(
"1: stxa %[ver], [%[addr]] %[asi]\n"
" mov 0, %[err]\n"
"2:\n"
" .section .fixup,#alloc,#execinstr\n"
" .align 4\n"
"3: sethi %%hi(2b), %%g1\n"
" jmpl %%g1 + %%lo(2b), %%g0\n"
" mov %[invalid], %[err]\n"
" .previous\n"
" .section __ex_table, \"a\"\n"
" .align 4\n"
" .word 1b, 3b\n"
" .previous\n"
: [err] "=r" (err)
: [ver] "r" (ver), [addr] "r" (addr),
[invalid] "i" (EFAULT), [asi] "i" (ASI_MCD_REAL)
: "memory", "g1"
);
if (err)
return -EFAULT;
else
return ver;
}
static ssize_t adi_write(struct file *file, const char __user *buf,
size_t count, loff_t *offp)
{
size_t ver_buf_sz, bytes_written = 0;
loff_t offset;
u8 *ver_buf;
ssize_t ret;
int i;
if (count <= 0)
return -EINVAL;
ver_buf_sz = min_t(size_t, count, MAX_BUF_SZ);
ver_buf = kmalloc(ver_buf_sz, GFP_KERNEL);
if (!ver_buf)
return -ENOMEM;
offset = (*offp) * adi_blksize();
do {
if (copy_from_user(ver_buf, &buf[bytes_written],
ver_buf_sz)) {
ret = -EFAULT;
goto out;
}
for (i = 0; i < ver_buf_sz; i++) {
ret = set_mcd_tag(offset, ver_buf[i]);
if (ret < 0)
goto out;
offset += adi_blksize();
}
bytes_written += ver_buf_sz;
ver_buf_sz = min(count - bytes_written, (size_t)MAX_BUF_SZ);
} while (bytes_written < count);
(*offp) += bytes_written;
ret = bytes_written;
out:
__asm__ __volatile__("membar #Sync");
kfree(ver_buf);
return ret;
}
static loff_t adi_llseek(struct file *file, loff_t offset, int whence)
{
loff_t ret = -EINVAL;
switch (whence) {
case SEEK_END:
case SEEK_DATA:
case SEEK_HOLE:
/* unsupported */
return -EINVAL;
case SEEK_CUR:
if (offset == 0)
return file->f_pos;
offset += file->f_pos;
break;
case SEEK_SET:
break;
}
if (offset != file->f_pos) {
file->f_pos = offset;
file->f_version = 0;
ret = offset;
}
return ret;
}
static const struct file_operations adi_fops = {
.owner = THIS_MODULE,
.llseek = adi_llseek,
.open = adi_open,
.read = adi_read,
.write = adi_write,
};
static struct miscdevice adi_miscdev = {
.minor = MISC_DYNAMIC_MINOR,
.name = KBUILD_MODNAME,
.fops = &adi_fops,
};
static int __init adi_init(void)
{
if (!adi_capable())
return -EPERM;
return misc_register(&adi_miscdev);
}
static void __exit adi_exit(void)
{
misc_deregister(&adi_miscdev);
}
module_init(adi_init);
module_exit(adi_exit);
MODULE_AUTHOR("Tom Hromatka <tom.hromatka@oracle.com>");
MODULE_DESCRIPTION("Privileged interface to ADI");
MODULE_VERSION("1.0");
MODULE_LICENSE("GPL v2");
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