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/*
* Alignment access counters and corresponding user-space interfaces.
*
* Copyright (C) 2009 ST Microelectronics
* Copyright (C) 2009 - 2010 Paul Mundt
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/seq_file.h>
#include <linux/proc_fs.h>
#include <linux/uaccess.h>
#include <linux/ratelimit.h>
#include <asm/alignment.h>
#include <asm/processor.h>
static unsigned long se_user;
static unsigned long se_sys;
static unsigned long se_half;
static unsigned long se_word;
static unsigned long se_dword;
static unsigned long se_multi;
/* bitfield: 1: warn 2: fixup 4: signal -> combinations 2|4 && 1|2|4 are not
valid! */
static int se_usermode = UM_WARN | UM_FIXUP;
/* 0: no warning 1: print a warning message, disabled by default */
static int se_kernmode_warn;
core_param(alignment, se_usermode, int, 0600);
void inc_unaligned_byte_access(void)
{
se_half++;
}
void inc_unaligned_word_access(void)
{
se_word++;
}
void inc_unaligned_dword_access(void)
{
se_dword++;
}
void inc_unaligned_multi_access(void)
{
se_multi++;
}
void inc_unaligned_user_access(void)
{
se_user++;
}
void inc_unaligned_kernel_access(void)
{
se_sys++;
}
/*
* This defaults to the global policy which can be set from the command
* line, while processes can overload their preferences via prctl().
*/
unsigned int unaligned_user_action(void)
{
unsigned int action = se_usermode;
if (current->thread.flags & SH_THREAD_UAC_SIGBUS) {
action &= ~UM_FIXUP;
action |= UM_SIGNAL;
}
if (current->thread.flags & SH_THREAD_UAC_NOPRINT)
action &= ~UM_WARN;
return action;
}
int get_unalign_ctl(struct task_struct *tsk, unsigned long addr)
{
return put_user(tsk->thread.flags & SH_THREAD_UAC_MASK,
(unsigned int __user *)addr);
}
int set_unalign_ctl(struct task_struct *tsk, unsigned int val)
{
tsk->thread.flags = (tsk->thread.flags & ~SH_THREAD_UAC_MASK) |
(val & SH_THREAD_UAC_MASK);
return 0;
}
void unaligned_fixups_notify(struct task_struct *tsk, insn_size_t insn,
struct pt_regs *regs)
{
if (user_mode(regs) && (se_usermode & UM_WARN))
pr_notice_ratelimited("Fixing up unaligned userspace access "
"in \"%s\" pid=%d pc=0x%p ins=0x%04hx\n",
tsk->comm, task_pid_nr(tsk),
(void *)instruction_pointer(regs), insn);
else if (se_kernmode_warn)
pr_notice_ratelimited("Fixing up unaligned kernel access "
"in \"%s\" pid=%d pc=0x%p ins=0x%04hx\n",
tsk->comm, task_pid_nr(tsk),
(void *)instruction_pointer(regs), insn);
}
static const char *se_usermode_action[] = {
"ignored",
"warn",
"fixup",
"fixup+warn",
"signal",
"signal+warn"
};
static int alignment_proc_show(struct seq_file *m, void *v)
{
seq_printf(m, "User:\t\t%lu\n", se_user);
seq_printf(m, "System:\t\t%lu\n", se_sys);
seq_printf(m, "Half:\t\t%lu\n", se_half);
seq_printf(m, "Word:\t\t%lu\n", se_word);
seq_printf(m, "DWord:\t\t%lu\n", se_dword);
seq_printf(m, "Multi:\t\t%lu\n", se_multi);
seq_printf(m, "User faults:\t%i (%s)\n", se_usermode,
se_usermode_action[se_usermode]);
seq_printf(m, "Kernel faults:\t%i (fixup%s)\n", se_kernmode_warn,
se_kernmode_warn ? "+warn" : "");
return 0;
}
static int alignment_proc_open(struct inode *inode, struct file *file)
{
return single_open(file, alignment_proc_show, NULL);
}
static ssize_t alignment_proc_write(struct file *file,
const char __user *buffer, size_t count, loff_t *pos)
{
int *data = PDE_DATA(file_inode(file));
char mode;
if (count > 0) {
if (get_user(mode, buffer))
return -EFAULT;
if (mode >= '0' && mode <= '5')
*data = mode - '0';
}
return count;
}
static const struct proc_ops alignment_proc_ops = {
.proc_open = alignment_proc_open,
.proc_read = seq_read,
.proc_lseek = seq_lseek,
.proc_release = single_release,
.proc_write = alignment_proc_write,
};
/*
* This needs to be done after sysctl_init, otherwise sys/ will be
* overwritten. Actually, this shouldn't be in sys/ at all since
* it isn't a sysctl, and it doesn't contain sysctl information.
* We now locate it in /proc/cpu/alignment instead.
*/
static int __init alignment_init(void)
{
struct proc_dir_entry *dir, *res;
dir = proc_mkdir("cpu", NULL);
if (!dir)
return -ENOMEM;
res = proc_create_data("alignment", S_IWUSR | S_IRUGO, dir,
&alignment_proc_ops, &se_usermode);
if (!res)
return -ENOMEM;
res = proc_create_data("kernel_alignment", S_IWUSR | S_IRUGO, dir,
&alignment_proc_ops, &se_kernmode_warn);
if (!res)
return -ENOMEM;
return 0;
}
fs_initcall(alignment_init);
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