--- /dev/null
+/*
+ * 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 file_operations alignment_proc_fops = {
+ .owner = THIS_MODULE,
+ .open = alignment_proc_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = single_release,
+ .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_fops, &se_usermode);
+ if (!res)
+ return -ENOMEM;
+
+ res = proc_create_data("kernel_alignment", S_IWUSR | S_IRUGO, dir,
+ &alignment_proc_fops, &se_kernmode_warn);
+ if (!res)
+ return -ENOMEM;
+
+ return 0;
+}
+fs_initcall(alignment_init);
Code Review / kvmfornfv.git / blobdiff