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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: Tom Hromatka <tom.hromatka@oracle.com> Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com> Reviewed-by: Shannon Nelson <shannon.nelson@oracle.com> Reviewed-by: Anthony Yznaga <anthony.yznaga@oracle.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Tom Hromatka
David S. Miller
parent
fff75eb2a0
commit
873c38a424
@ -540,5 +540,17 @@ source "drivers/s390/char/Kconfig"
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source "drivers/char/xillybus/Kconfig"
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config ADI
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tristate "SPARC Privileged ADI driver"
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depends on SPARC64
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default m
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help
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SPARC M7 and newer processors utilize ADI (Application Data
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Integrity) to version and protect memory. This driver provides
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read/write access to the ADI versions for privileged processes.
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This feature is also known as MCD (Memory Corruption Detection)
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and SSM (Silicon Secured Memory). Intended consumers of this
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driver include crash and makedumpfile.
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endmenu
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@ -57,3 +57,4 @@ js-rtc-y = rtc.o
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obj-$(CONFIG_XILLYBUS) += xillybus/
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obj-$(CONFIG_POWERNV_OP_PANEL) += powernv-op-panel.o
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obj-$(CONFIG_ADI) += adi.o
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239
drivers/char/adi.c
Normal file
239
drivers/char/adi.c
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@ -0,0 +1,239 @@
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// SPDX-License-Identifier: GPL-2.0
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/*
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* Privileged ADI driver for sparc64
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*
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* Author: Tom Hromatka <tom.hromatka@oracle.com>
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*/
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#include <linux/kernel.h>
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#include <linux/miscdevice.h>
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#include <linux/module.h>
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#include <linux/proc_fs.h>
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#include <linux/slab.h>
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#include <linux/uaccess.h>
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#include <asm/asi.h>
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#define MAX_BUF_SZ PAGE_SIZE
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static int adi_open(struct inode *inode, struct file *file)
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{
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file->f_mode |= FMODE_UNSIGNED_OFFSET;
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return 0;
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}
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static int read_mcd_tag(unsigned long addr)
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{
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long err;
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int ver;
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__asm__ __volatile__(
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"1: ldxa [%[addr]] %[asi], %[ver]\n"
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" mov 0, %[err]\n"
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"2:\n"
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" .section .fixup,#alloc,#execinstr\n"
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" .align 4\n"
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"3: sethi %%hi(2b), %%g1\n"
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" jmpl %%g1 + %%lo(2b), %%g0\n"
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" mov %[invalid], %[err]\n"
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" .previous\n"
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" .section __ex_table, \"a\"\n"
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" .align 4\n"
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" .word 1b, 3b\n"
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" .previous\n"
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: [ver] "=r" (ver), [err] "=r" (err)
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: [addr] "r" (addr), [invalid] "i" (EFAULT),
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[asi] "i" (ASI_MCD_REAL)
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: "memory", "g1"
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);
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if (err)
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return -EFAULT;
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else
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return ver;
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}
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static ssize_t adi_read(struct file *file, char __user *buf,
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size_t count, loff_t *offp)
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{
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size_t ver_buf_sz, bytes_read = 0;
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int ver_buf_idx = 0;
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loff_t offset;
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u8 *ver_buf;
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ssize_t ret;
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ver_buf_sz = min_t(size_t, count, MAX_BUF_SZ);
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ver_buf = kmalloc(ver_buf_sz, GFP_KERNEL);
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if (!ver_buf)
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return -ENOMEM;
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offset = (*offp) * adi_blksize();
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while (bytes_read < count) {
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ret = read_mcd_tag(offset);
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if (ret < 0)
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goto out;
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ver_buf[ver_buf_idx] = (u8)ret;
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ver_buf_idx++;
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offset += adi_blksize();
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if (ver_buf_idx >= ver_buf_sz) {
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if (copy_to_user(buf + bytes_read, ver_buf,
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ver_buf_sz)) {
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ret = -EFAULT;
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goto out;
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}
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bytes_read += ver_buf_sz;
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ver_buf_idx = 0;
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ver_buf_sz = min(count - bytes_read,
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(size_t)MAX_BUF_SZ);
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}
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}
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(*offp) += bytes_read;
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ret = bytes_read;
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out:
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kfree(ver_buf);
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return ret;
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}
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static int set_mcd_tag(unsigned long addr, u8 ver)
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{
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long err;
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__asm__ __volatile__(
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"1: stxa %[ver], [%[addr]] %[asi]\n"
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" mov 0, %[err]\n"
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"2:\n"
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" .section .fixup,#alloc,#execinstr\n"
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" .align 4\n"
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"3: sethi %%hi(2b), %%g1\n"
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" jmpl %%g1 + %%lo(2b), %%g0\n"
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" mov %[invalid], %[err]\n"
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" .previous\n"
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" .section __ex_table, \"a\"\n"
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" .align 4\n"
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" .word 1b, 3b\n"
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" .previous\n"
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: [err] "=r" (err)
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: [ver] "r" (ver), [addr] "r" (addr),
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[invalid] "i" (EFAULT), [asi] "i" (ASI_MCD_REAL)
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: "memory", "g1"
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);
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if (err)
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return -EFAULT;
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else
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return ver;
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}
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static ssize_t adi_write(struct file *file, const char __user *buf,
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size_t count, loff_t *offp)
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{
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size_t ver_buf_sz, bytes_written = 0;
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loff_t offset;
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u8 *ver_buf;
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ssize_t ret;
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int i;
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if (count <= 0)
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return -EINVAL;
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ver_buf_sz = min_t(size_t, count, MAX_BUF_SZ);
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ver_buf = kmalloc(ver_buf_sz, GFP_KERNEL);
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if (!ver_buf)
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return -ENOMEM;
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offset = (*offp) * adi_blksize();
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do {
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if (copy_from_user(ver_buf, &buf[bytes_written],
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ver_buf_sz)) {
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ret = -EFAULT;
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goto out;
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}
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for (i = 0; i < ver_buf_sz; i++) {
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ret = set_mcd_tag(offset, ver_buf[i]);
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if (ret < 0)
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goto out;
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offset += adi_blksize();
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}
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bytes_written += ver_buf_sz;
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ver_buf_sz = min(count - bytes_written, (size_t)MAX_BUF_SZ);
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} while (bytes_written < count);
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(*offp) += bytes_written;
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ret = bytes_written;
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out:
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__asm__ __volatile__("membar #Sync");
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kfree(ver_buf);
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return ret;
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}
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static loff_t adi_llseek(struct file *file, loff_t offset, int whence)
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{
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loff_t ret = -EINVAL;
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switch (whence) {
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case SEEK_END:
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case SEEK_DATA:
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case SEEK_HOLE:
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/* unsupported */
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return -EINVAL;
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case SEEK_CUR:
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if (offset == 0)
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return file->f_pos;
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offset += file->f_pos;
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break;
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case SEEK_SET:
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break;
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}
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if (offset != file->f_pos) {
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file->f_pos = offset;
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file->f_version = 0;
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ret = offset;
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}
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return ret;
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}
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static const struct file_operations adi_fops = {
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.owner = THIS_MODULE,
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.llseek = adi_llseek,
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.open = adi_open,
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.read = adi_read,
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.write = adi_write,
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};
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static struct miscdevice adi_miscdev = {
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.minor = MISC_DYNAMIC_MINOR,
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.name = KBUILD_MODNAME,
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.fops = &adi_fops,
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};
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static int __init adi_init(void)
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{
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if (!adi_capable())
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return -EPERM;
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return misc_register(&adi_miscdev);
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}
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static void __exit adi_exit(void)
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{
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misc_deregister(&adi_miscdev);
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}
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module_init(adi_init);
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module_exit(adi_exit);
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MODULE_AUTHOR("Tom Hromatka <tom.hromatka@oracle.com>");
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MODULE_DESCRIPTION("Privileged interface to ADI");
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MODULE_VERSION("1.0");
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MODULE_LICENSE("GPL v2");
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