Paul Mundt | a99eae5 | 2010-01-12 16:12:25 +0900 | [diff] [blame] | 1 | /* |
| 2 | * Alignment access counters and corresponding user-space interfaces. |
| 3 | * |
| 4 | * Copyright (C) 2009 ST Microelectronics |
| 5 | * Copyright (C) 2009 - 2010 Paul Mundt |
| 6 | * |
| 7 | * This file is subject to the terms and conditions of the GNU General Public |
| 8 | * License. See the file "COPYING" in the main directory of this archive |
| 9 | * for more details. |
| 10 | */ |
| 11 | #include <linux/module.h> |
| 12 | #include <linux/kernel.h> |
| 13 | #include <linux/seq_file.h> |
| 14 | #include <linux/proc_fs.h> |
| 15 | #include <linux/uaccess.h> |
Paul Mundt | 9ab3a15 | 2011-06-30 15:10:06 +0900 | [diff] [blame] | 16 | #include <linux/ratelimit.h> |
Paul Mundt | a99eae5 | 2010-01-12 16:12:25 +0900 | [diff] [blame] | 17 | #include <asm/alignment.h> |
Paul Mundt | 94ea5e4 | 2010-02-23 12:56:30 +0900 | [diff] [blame] | 18 | #include <asm/processor.h> |
Paul Mundt | a99eae5 | 2010-01-12 16:12:25 +0900 | [diff] [blame] | 19 | |
| 20 | static unsigned long se_user; |
| 21 | static unsigned long se_sys; |
| 22 | static unsigned long se_half; |
| 23 | static unsigned long se_word; |
| 24 | static unsigned long se_dword; |
| 25 | static unsigned long se_multi; |
| 26 | /* bitfield: 1: warn 2: fixup 4: signal -> combinations 2|4 && 1|2|4 are not |
| 27 | valid! */ |
| 28 | static int se_usermode = UM_WARN | UM_FIXUP; |
| 29 | /* 0: no warning 1: print a warning message, disabled by default */ |
| 30 | static int se_kernmode_warn; |
| 31 | |
Paul Mundt | 7c1b2c6 | 2010-02-23 11:48:50 +0900 | [diff] [blame] | 32 | core_param(alignment, se_usermode, int, 0600); |
| 33 | |
Paul Mundt | a99eae5 | 2010-01-12 16:12:25 +0900 | [diff] [blame] | 34 | void inc_unaligned_byte_access(void) |
| 35 | { |
| 36 | se_half++; |
| 37 | } |
| 38 | |
| 39 | void inc_unaligned_word_access(void) |
| 40 | { |
| 41 | se_word++; |
| 42 | } |
| 43 | |
| 44 | void inc_unaligned_dword_access(void) |
| 45 | { |
| 46 | se_dword++; |
| 47 | } |
| 48 | |
| 49 | void inc_unaligned_multi_access(void) |
| 50 | { |
| 51 | se_multi++; |
| 52 | } |
| 53 | |
| 54 | void inc_unaligned_user_access(void) |
| 55 | { |
| 56 | se_user++; |
| 57 | } |
| 58 | |
| 59 | void inc_unaligned_kernel_access(void) |
| 60 | { |
| 61 | se_sys++; |
| 62 | } |
| 63 | |
Paul Mundt | 94ea5e4 | 2010-02-23 12:56:30 +0900 | [diff] [blame] | 64 | /* |
| 65 | * This defaults to the global policy which can be set from the command |
| 66 | * line, while processes can overload their preferences via prctl(). |
| 67 | */ |
Paul Mundt | a99eae5 | 2010-01-12 16:12:25 +0900 | [diff] [blame] | 68 | unsigned int unaligned_user_action(void) |
| 69 | { |
Paul Mundt | 94ea5e4 | 2010-02-23 12:56:30 +0900 | [diff] [blame] | 70 | unsigned int action = se_usermode; |
| 71 | |
| 72 | if (current->thread.flags & SH_THREAD_UAC_SIGBUS) { |
| 73 | action &= ~UM_FIXUP; |
| 74 | action |= UM_SIGNAL; |
| 75 | } |
| 76 | |
| 77 | if (current->thread.flags & SH_THREAD_UAC_NOPRINT) |
| 78 | action &= ~UM_WARN; |
| 79 | |
| 80 | return action; |
| 81 | } |
| 82 | |
| 83 | int get_unalign_ctl(struct task_struct *tsk, unsigned long addr) |
| 84 | { |
| 85 | return put_user(tsk->thread.flags & SH_THREAD_UAC_MASK, |
| 86 | (unsigned int __user *)addr); |
| 87 | } |
| 88 | |
| 89 | int set_unalign_ctl(struct task_struct *tsk, unsigned int val) |
| 90 | { |
| 91 | tsk->thread.flags = (tsk->thread.flags & ~SH_THREAD_UAC_MASK) | |
| 92 | (val & SH_THREAD_UAC_MASK); |
| 93 | return 0; |
Paul Mundt | a99eae5 | 2010-01-12 16:12:25 +0900 | [diff] [blame] | 94 | } |
| 95 | |
| 96 | void unaligned_fixups_notify(struct task_struct *tsk, insn_size_t insn, |
| 97 | struct pt_regs *regs) |
| 98 | { |
Paul Mundt | 9ab3a15 | 2011-06-30 15:10:06 +0900 | [diff] [blame] | 99 | if (user_mode(regs) && (se_usermode & UM_WARN)) |
| 100 | pr_notice_ratelimited("Fixing up unaligned userspace access " |
Paul Mundt | a99eae5 | 2010-01-12 16:12:25 +0900 | [diff] [blame] | 101 | "in \"%s\" pid=%d pc=0x%p ins=0x%04hx\n", |
| 102 | tsk->comm, task_pid_nr(tsk), |
Paul Mundt | 88ea1a4 | 2010-01-19 15:41:50 +0900 | [diff] [blame] | 103 | (void *)instruction_pointer(regs), insn); |
Paul Mundt | 9ab3a15 | 2011-06-30 15:10:06 +0900 | [diff] [blame] | 104 | else if (se_kernmode_warn) |
| 105 | pr_notice_ratelimited("Fixing up unaligned kernel access " |
Paul Mundt | a99eae5 | 2010-01-12 16:12:25 +0900 | [diff] [blame] | 106 | "in \"%s\" pid=%d pc=0x%p ins=0x%04hx\n", |
| 107 | tsk->comm, task_pid_nr(tsk), |
Paul Mundt | 88ea1a4 | 2010-01-19 15:41:50 +0900 | [diff] [blame] | 108 | (void *)instruction_pointer(regs), insn); |
Paul Mundt | a99eae5 | 2010-01-12 16:12:25 +0900 | [diff] [blame] | 109 | } |
| 110 | |
| 111 | static const char *se_usermode_action[] = { |
| 112 | "ignored", |
| 113 | "warn", |
| 114 | "fixup", |
| 115 | "fixup+warn", |
| 116 | "signal", |
| 117 | "signal+warn" |
| 118 | }; |
| 119 | |
| 120 | static int alignment_proc_show(struct seq_file *m, void *v) |
| 121 | { |
| 122 | seq_printf(m, "User:\t\t%lu\n", se_user); |
| 123 | seq_printf(m, "System:\t\t%lu\n", se_sys); |
| 124 | seq_printf(m, "Half:\t\t%lu\n", se_half); |
| 125 | seq_printf(m, "Word:\t\t%lu\n", se_word); |
| 126 | seq_printf(m, "DWord:\t\t%lu\n", se_dword); |
| 127 | seq_printf(m, "Multi:\t\t%lu\n", se_multi); |
| 128 | seq_printf(m, "User faults:\t%i (%s)\n", se_usermode, |
| 129 | se_usermode_action[se_usermode]); |
| 130 | seq_printf(m, "Kernel faults:\t%i (fixup%s)\n", se_kernmode_warn, |
| 131 | se_kernmode_warn ? "+warn" : ""); |
| 132 | return 0; |
| 133 | } |
| 134 | |
| 135 | static int alignment_proc_open(struct inode *inode, struct file *file) |
| 136 | { |
| 137 | return single_open(file, alignment_proc_show, NULL); |
| 138 | } |
| 139 | |
| 140 | static ssize_t alignment_proc_write(struct file *file, |
| 141 | const char __user *buffer, size_t count, loff_t *pos) |
| 142 | { |
Al Viro | 496ad9a | 2013-01-23 17:07:38 -0500 | [diff] [blame] | 143 | int *data = PDE(file_inode(file))->data; |
Paul Mundt | a99eae5 | 2010-01-12 16:12:25 +0900 | [diff] [blame] | 144 | char mode; |
| 145 | |
| 146 | if (count > 0) { |
| 147 | if (get_user(mode, buffer)) |
| 148 | return -EFAULT; |
| 149 | if (mode >= '0' && mode <= '5') |
| 150 | *data = mode - '0'; |
| 151 | } |
| 152 | return count; |
| 153 | } |
| 154 | |
| 155 | static const struct file_operations alignment_proc_fops = { |
| 156 | .owner = THIS_MODULE, |
| 157 | .open = alignment_proc_open, |
| 158 | .read = seq_read, |
| 159 | .llseek = seq_lseek, |
| 160 | .release = single_release, |
| 161 | .write = alignment_proc_write, |
| 162 | }; |
| 163 | |
| 164 | /* |
| 165 | * This needs to be done after sysctl_init, otherwise sys/ will be |
| 166 | * overwritten. Actually, this shouldn't be in sys/ at all since |
| 167 | * it isn't a sysctl, and it doesn't contain sysctl information. |
| 168 | * We now locate it in /proc/cpu/alignment instead. |
| 169 | */ |
| 170 | static int __init alignment_init(void) |
| 171 | { |
| 172 | struct proc_dir_entry *dir, *res; |
| 173 | |
| 174 | dir = proc_mkdir("cpu", NULL); |
| 175 | if (!dir) |
| 176 | return -ENOMEM; |
| 177 | |
| 178 | res = proc_create_data("alignment", S_IWUSR | S_IRUGO, dir, |
| 179 | &alignment_proc_fops, &se_usermode); |
| 180 | if (!res) |
| 181 | return -ENOMEM; |
| 182 | |
| 183 | res = proc_create_data("kernel_alignment", S_IWUSR | S_IRUGO, dir, |
| 184 | &alignment_proc_fops, &se_kernmode_warn); |
| 185 | if (!res) |
| 186 | return -ENOMEM; |
| 187 | |
| 188 | return 0; |
| 189 | } |
| 190 | fs_initcall(alignment_init); |