Commit 873c38a4 authored by Tom Hromatka's avatar Tom Hromatka Committed by David S. Miller

char: sparc64: Add privileged ADI driver

SPARC M7 and newer processors utilize ADI to version and
protect memory.  This driver is capable of reading/writing
ADI/MCD versions from privileged user space processes.
Addresses in the adi file are mapped linearly to physical
memory at a ratio of 1:adi_blksz.  Thus, a read (or write)
of offset K in the file operates upon the ADI version at
physical address K * adi_blksz.  The version information
is encoded as one version per byte.  Intended consumers
are makedumpfile and crash.
Signed-off-by: default avatarTom Hromatka <tom.hromatka@oracle.com>
Reviewed-by: default avatarKhalid Aziz <khalid.aziz@oracle.com>
Reviewed-by: default avatarShannon Nelson <shannon.nelson@oracle.com>
Reviewed-by: default avatarAnthony Yznaga <anthony.yznaga@oracle.com>
Reviewed-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent fff75eb2
......@@ -540,5 +540,17 @@ source "drivers/s390/char/Kconfig"
source "drivers/char/xillybus/Kconfig"
config ADI
tristate "SPARC Privileged ADI driver"
depends on SPARC64
default m
help
SPARC M7 and newer processors utilize ADI (Application Data
Integrity) to version and protect memory. This driver provides
read/write access to the ADI versions for privileged processes.
This feature is also known as MCD (Memory Corruption Detection)
and SSM (Silicon Secured Memory). Intended consumers of this
driver include crash and makedumpfile.
endmenu
......@@ -57,3 +57,4 @@ js-rtc-y = rtc.o
obj-$(CONFIG_XILLYBUS) += xillybus/
obj-$(CONFIG_POWERNV_OP_PANEL) += powernv-op-panel.o
obj-$(CONFIG_ADI) += adi.o
// 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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