K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 1 | /* |
| 2 | * This program is free software; you can redistribute it and/or modify |
| 3 | * it under the terms of the GNU General Public License as published by |
| 4 | * the Free Software Foundation; either version 2 of the License, or |
| 5 | * (at your option) any later version. |
| 6 | * |
| 7 | * This program is distributed in the hope that it will be useful, |
| 8 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 9 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 10 | * GNU General Public License for more details. |
| 11 | * |
| 12 | * You should have received a copy of the GNU General Public License |
| 13 | * along with this program; if not, write to the Free Software |
| 14 | * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
| 15 | * |
| 16 | * Copyright (C) 2007 Alan Stern |
| 17 | * Copyright (C) 2009 IBM Corporation |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 18 | * Copyright (C) 2009 Frederic Weisbecker <fweisbec@gmail.com> |
K.Prasad | ba6909b | 2009-11-23 21:17:13 +0530 | [diff] [blame] | 19 | * |
| 20 | * Authors: Alan Stern <stern@rowland.harvard.edu> |
| 21 | * K.Prasad <prasad@linux.vnet.ibm.com> |
| 22 | * Frederic Weisbecker <fweisbec@gmail.com> |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 23 | */ |
| 24 | |
| 25 | /* |
| 26 | * HW_breakpoint: a unified kernel/user-space hardware breakpoint facility, |
| 27 | * using the CPU's debug registers. |
| 28 | */ |
| 29 | |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 30 | #include <linux/perf_event.h> |
| 31 | #include <linux/hw_breakpoint.h> |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 32 | #include <linux/irqflags.h> |
| 33 | #include <linux/notifier.h> |
| 34 | #include <linux/kallsyms.h> |
| 35 | #include <linux/kprobes.h> |
| 36 | #include <linux/percpu.h> |
| 37 | #include <linux/kdebug.h> |
| 38 | #include <linux/kernel.h> |
| 39 | #include <linux/module.h> |
| 40 | #include <linux/sched.h> |
| 41 | #include <linux/init.h> |
| 42 | #include <linux/smp.h> |
| 43 | |
| 44 | #include <asm/hw_breakpoint.h> |
| 45 | #include <asm/processor.h> |
| 46 | #include <asm/debugreg.h> |
| 47 | |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 48 | /* Per cpu debug control register value */ |
Tejun Heo | 28b4e0d | 2009-11-25 22:24:44 +0900 | [diff] [blame] | 49 | DEFINE_PER_CPU(unsigned long, cpu_dr7); |
| 50 | EXPORT_PER_CPU_SYMBOL(cpu_dr7); |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 51 | |
| 52 | /* Per cpu debug address registers values */ |
| 53 | static DEFINE_PER_CPU(unsigned long, cpu_debugreg[HBP_NUM]); |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 54 | |
| 55 | /* |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 56 | * Stores the breakpoints currently in use on each breakpoint address |
| 57 | * register for each cpus |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 58 | */ |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 59 | static DEFINE_PER_CPU(struct perf_event *, bp_per_reg[HBP_NUM]); |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 60 | |
| 61 | |
Frederic Weisbecker | 2c31b79 | 2009-11-26 06:04:38 +0100 | [diff] [blame] | 62 | static inline unsigned long |
| 63 | __encode_dr7(int drnum, unsigned int len, unsigned int type) |
| 64 | { |
| 65 | unsigned long bp_info; |
| 66 | |
| 67 | bp_info = (len | type) & 0xf; |
| 68 | bp_info <<= (DR_CONTROL_SHIFT + drnum * DR_CONTROL_SIZE); |
| 69 | bp_info |= (DR_GLOBAL_ENABLE << (drnum * DR_ENABLE_SIZE)); |
| 70 | |
| 71 | return bp_info; |
| 72 | } |
| 73 | |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 74 | /* |
| 75 | * Encode the length, type, Exact, and Enable bits for a particular breakpoint |
| 76 | * as stored in debug register 7. |
| 77 | */ |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 78 | unsigned long encode_dr7(int drnum, unsigned int len, unsigned int type) |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 79 | { |
Frederic Weisbecker | 2c31b79 | 2009-11-26 06:04:38 +0100 | [diff] [blame] | 80 | return __encode_dr7(drnum, len, type) | DR_GLOBAL_SLOWDOWN; |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 81 | } |
| 82 | |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 83 | /* |
| 84 | * Decode the length and type bits for a particular breakpoint as |
| 85 | * stored in debug register 7. Return the "enabled" status. |
| 86 | */ |
| 87 | int decode_dr7(unsigned long dr7, int bpnum, unsigned *len, unsigned *type) |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 88 | { |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 89 | int bp_info = dr7 >> (DR_CONTROL_SHIFT + bpnum * DR_CONTROL_SIZE); |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 90 | |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 91 | *len = (bp_info & 0xc) | 0x40; |
| 92 | *type = (bp_info & 0x3) | 0x80; |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 93 | |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 94 | return (dr7 >> (bpnum * DR_ENABLE_SIZE)) & 0x3; |
| 95 | } |
| 96 | |
| 97 | /* |
| 98 | * Install a perf counter breakpoint. |
| 99 | * |
| 100 | * We seek a free debug address register and use it for this |
| 101 | * breakpoint. Eventually we enable it in the debug control register. |
| 102 | * |
| 103 | * Atomic: we hold the counter->ctx->lock and we only handle variables |
| 104 | * and registers local to this cpu. |
| 105 | */ |
| 106 | int arch_install_hw_breakpoint(struct perf_event *bp) |
| 107 | { |
| 108 | struct arch_hw_breakpoint *info = counter_arch_bp(bp); |
| 109 | unsigned long *dr7; |
| 110 | int i; |
| 111 | |
| 112 | for (i = 0; i < HBP_NUM; i++) { |
| 113 | struct perf_event **slot = &__get_cpu_var(bp_per_reg[i]); |
| 114 | |
| 115 | if (!*slot) { |
| 116 | *slot = bp; |
| 117 | break; |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 118 | } |
| 119 | } |
| 120 | |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 121 | if (WARN_ONCE(i == HBP_NUM, "Can't find any breakpoint slot")) |
| 122 | return -EBUSY; |
| 123 | |
| 124 | set_debugreg(info->address, i); |
| 125 | __get_cpu_var(cpu_debugreg[i]) = info->address; |
| 126 | |
Tejun Heo | 28b4e0d | 2009-11-25 22:24:44 +0900 | [diff] [blame] | 127 | dr7 = &__get_cpu_var(cpu_dr7); |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 128 | *dr7 |= encode_dr7(i, info->len, info->type); |
| 129 | |
| 130 | set_debugreg(*dr7, 7); |
| 131 | |
| 132 | return 0; |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 133 | } |
| 134 | |
| 135 | /* |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 136 | * Uninstall the breakpoint contained in the given counter. |
| 137 | * |
| 138 | * First we search the debug address register it uses and then we disable |
| 139 | * it. |
| 140 | * |
| 141 | * Atomic: we hold the counter->ctx->lock and we only handle variables |
| 142 | * and registers local to this cpu. |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 143 | */ |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 144 | void arch_uninstall_hw_breakpoint(struct perf_event *bp) |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 145 | { |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 146 | struct arch_hw_breakpoint *info = counter_arch_bp(bp); |
| 147 | unsigned long *dr7; |
| 148 | int i; |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 149 | |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 150 | for (i = 0; i < HBP_NUM; i++) { |
| 151 | struct perf_event **slot = &__get_cpu_var(bp_per_reg[i]); |
| 152 | |
| 153 | if (*slot == bp) { |
| 154 | *slot = NULL; |
| 155 | break; |
| 156 | } |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 157 | } |
| 158 | |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 159 | if (WARN_ONCE(i == HBP_NUM, "Can't find any breakpoint slot")) |
| 160 | return; |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 161 | |
Tejun Heo | 28b4e0d | 2009-11-25 22:24:44 +0900 | [diff] [blame] | 162 | dr7 = &__get_cpu_var(cpu_dr7); |
Frederic Weisbecker | 2c31b79 | 2009-11-26 06:04:38 +0100 | [diff] [blame] | 163 | *dr7 &= ~__encode_dr7(i, info->len, info->type); |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 164 | |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 165 | set_debugreg(*dr7, 7); |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 166 | } |
| 167 | |
| 168 | static int get_hbp_len(u8 hbp_len) |
| 169 | { |
| 170 | unsigned int len_in_bytes = 0; |
| 171 | |
| 172 | switch (hbp_len) { |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 173 | case X86_BREAKPOINT_LEN_1: |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 174 | len_in_bytes = 1; |
| 175 | break; |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 176 | case X86_BREAKPOINT_LEN_2: |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 177 | len_in_bytes = 2; |
| 178 | break; |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 179 | case X86_BREAKPOINT_LEN_4: |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 180 | len_in_bytes = 4; |
| 181 | break; |
| 182 | #ifdef CONFIG_X86_64 |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 183 | case X86_BREAKPOINT_LEN_8: |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 184 | len_in_bytes = 8; |
| 185 | break; |
| 186 | #endif |
| 187 | } |
| 188 | return len_in_bytes; |
| 189 | } |
| 190 | |
| 191 | /* |
| 192 | * Check for virtual address in user space. |
| 193 | */ |
| 194 | int arch_check_va_in_userspace(unsigned long va, u8 hbp_len) |
| 195 | { |
| 196 | unsigned int len; |
| 197 | |
| 198 | len = get_hbp_len(hbp_len); |
| 199 | |
| 200 | return (va <= TASK_SIZE - len); |
| 201 | } |
| 202 | |
| 203 | /* |
| 204 | * Check for virtual address in kernel space. |
| 205 | */ |
Jaswinder Singh Rajput | 4555835 | 2009-06-17 14:44:19 +0530 | [diff] [blame] | 206 | static int arch_check_va_in_kernelspace(unsigned long va, u8 hbp_len) |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 207 | { |
| 208 | unsigned int len; |
| 209 | |
| 210 | len = get_hbp_len(hbp_len); |
| 211 | |
| 212 | return (va >= TASK_SIZE) && ((va + len - 1) >= TASK_SIZE); |
| 213 | } |
| 214 | |
| 215 | /* |
| 216 | * Store a breakpoint's encoded address, length, and type. |
| 217 | */ |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 218 | static int arch_store_info(struct perf_event *bp) |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 219 | { |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 220 | struct arch_hw_breakpoint *info = counter_arch_bp(bp); |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 221 | /* |
| 222 | * For kernel-addresses, either the address or symbol name can be |
| 223 | * specified. |
| 224 | */ |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 225 | if (info->name) |
| 226 | info->address = (unsigned long) |
| 227 | kallsyms_lookup_name(info->name); |
| 228 | if (info->address) |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 229 | return 0; |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 230 | |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 231 | return -EINVAL; |
| 232 | } |
| 233 | |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 234 | int arch_bp_generic_fields(int x86_len, int x86_type, |
| 235 | int *gen_len, int *gen_type) |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 236 | { |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 237 | /* Len */ |
| 238 | switch (x86_len) { |
| 239 | case X86_BREAKPOINT_LEN_1: |
| 240 | *gen_len = HW_BREAKPOINT_LEN_1; |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 241 | break; |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 242 | case X86_BREAKPOINT_LEN_2: |
| 243 | *gen_len = HW_BREAKPOINT_LEN_2; |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 244 | break; |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 245 | case X86_BREAKPOINT_LEN_4: |
| 246 | *gen_len = HW_BREAKPOINT_LEN_4; |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 247 | break; |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 248 | #ifdef CONFIG_X86_64 |
| 249 | case X86_BREAKPOINT_LEN_8: |
| 250 | *gen_len = HW_BREAKPOINT_LEN_8; |
| 251 | break; |
| 252 | #endif |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 253 | default: |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 254 | return -EINVAL; |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 255 | } |
| 256 | |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 257 | /* Type */ |
| 258 | switch (x86_type) { |
| 259 | case X86_BREAKPOINT_EXECUTE: |
| 260 | *gen_type = HW_BREAKPOINT_X; |
| 261 | break; |
| 262 | case X86_BREAKPOINT_WRITE: |
| 263 | *gen_type = HW_BREAKPOINT_W; |
| 264 | break; |
| 265 | case X86_BREAKPOINT_RW: |
| 266 | *gen_type = HW_BREAKPOINT_W | HW_BREAKPOINT_R; |
| 267 | break; |
| 268 | default: |
| 269 | return -EINVAL; |
| 270 | } |
| 271 | |
| 272 | return 0; |
| 273 | } |
| 274 | |
| 275 | |
| 276 | static int arch_build_bp_info(struct perf_event *bp) |
| 277 | { |
| 278 | struct arch_hw_breakpoint *info = counter_arch_bp(bp); |
| 279 | |
| 280 | info->address = bp->attr.bp_addr; |
| 281 | |
| 282 | /* Len */ |
| 283 | switch (bp->attr.bp_len) { |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 284 | case HW_BREAKPOINT_LEN_1: |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 285 | info->len = X86_BREAKPOINT_LEN_1; |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 286 | break; |
| 287 | case HW_BREAKPOINT_LEN_2: |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 288 | info->len = X86_BREAKPOINT_LEN_2; |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 289 | break; |
| 290 | case HW_BREAKPOINT_LEN_4: |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 291 | info->len = X86_BREAKPOINT_LEN_4; |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 292 | break; |
| 293 | #ifdef CONFIG_X86_64 |
| 294 | case HW_BREAKPOINT_LEN_8: |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 295 | info->len = X86_BREAKPOINT_LEN_8; |
| 296 | break; |
| 297 | #endif |
| 298 | default: |
| 299 | return -EINVAL; |
| 300 | } |
| 301 | |
| 302 | /* Type */ |
| 303 | switch (bp->attr.bp_type) { |
| 304 | case HW_BREAKPOINT_W: |
| 305 | info->type = X86_BREAKPOINT_WRITE; |
| 306 | break; |
| 307 | case HW_BREAKPOINT_W | HW_BREAKPOINT_R: |
| 308 | info->type = X86_BREAKPOINT_RW; |
| 309 | break; |
| 310 | case HW_BREAKPOINT_X: |
| 311 | info->type = X86_BREAKPOINT_EXECUTE; |
| 312 | break; |
| 313 | default: |
| 314 | return -EINVAL; |
| 315 | } |
| 316 | |
| 317 | return 0; |
| 318 | } |
| 319 | /* |
| 320 | * Validate the arch-specific HW Breakpoint register settings |
| 321 | */ |
| 322 | int arch_validate_hwbkpt_settings(struct perf_event *bp, |
| 323 | struct task_struct *tsk) |
| 324 | { |
| 325 | struct arch_hw_breakpoint *info = counter_arch_bp(bp); |
| 326 | unsigned int align; |
| 327 | int ret; |
| 328 | |
| 329 | |
| 330 | ret = arch_build_bp_info(bp); |
| 331 | if (ret) |
| 332 | return ret; |
| 333 | |
| 334 | ret = -EINVAL; |
| 335 | |
| 336 | if (info->type == X86_BREAKPOINT_EXECUTE) |
| 337 | /* |
| 338 | * Ptrace-refactoring code |
| 339 | * For now, we'll allow instruction breakpoint only for user-space |
| 340 | * addresses |
| 341 | */ |
| 342 | if ((!arch_check_va_in_userspace(info->address, info->len)) && |
| 343 | info->len != X86_BREAKPOINT_EXECUTE) |
| 344 | return ret; |
| 345 | |
| 346 | switch (info->len) { |
| 347 | case X86_BREAKPOINT_LEN_1: |
| 348 | align = 0; |
| 349 | break; |
| 350 | case X86_BREAKPOINT_LEN_2: |
| 351 | align = 1; |
| 352 | break; |
| 353 | case X86_BREAKPOINT_LEN_4: |
| 354 | align = 3; |
| 355 | break; |
| 356 | #ifdef CONFIG_X86_64 |
| 357 | case X86_BREAKPOINT_LEN_8: |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 358 | align = 7; |
| 359 | break; |
| 360 | #endif |
| 361 | default: |
| 362 | return ret; |
| 363 | } |
| 364 | |
Frederic Weisbecker | b326e95 | 2009-12-05 09:44:31 +0100 | [diff] [blame] | 365 | ret = arch_store_info(bp); |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 366 | |
| 367 | if (ret < 0) |
| 368 | return ret; |
| 369 | /* |
| 370 | * Check that the low-order bits of the address are appropriate |
| 371 | * for the alignment implied by len. |
| 372 | */ |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 373 | if (info->address & align) |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 374 | return -EINVAL; |
| 375 | |
| 376 | /* Check that the virtual address is in the proper range */ |
| 377 | if (tsk) { |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 378 | if (!arch_check_va_in_userspace(info->address, info->len)) |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 379 | return -EFAULT; |
| 380 | } else { |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 381 | if (!arch_check_va_in_kernelspace(info->address, info->len)) |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 382 | return -EFAULT; |
| 383 | } |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 384 | |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 385 | return 0; |
| 386 | } |
| 387 | |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 388 | /* |
Frederic Weisbecker | 9f6b3c2 | 2009-11-09 21:03:43 +0100 | [diff] [blame] | 389 | * Dump the debug register contents to the user. |
| 390 | * We can't dump our per cpu values because it |
| 391 | * may contain cpu wide breakpoint, something that |
| 392 | * doesn't belong to the current task. |
| 393 | * |
| 394 | * TODO: include non-ptrace user breakpoints (perf) |
| 395 | */ |
| 396 | void aout_dump_debugregs(struct user *dump) |
| 397 | { |
| 398 | int i; |
| 399 | int dr7 = 0; |
| 400 | struct perf_event *bp; |
| 401 | struct arch_hw_breakpoint *info; |
| 402 | struct thread_struct *thread = ¤t->thread; |
| 403 | |
| 404 | for (i = 0; i < HBP_NUM; i++) { |
| 405 | bp = thread->ptrace_bps[i]; |
| 406 | |
| 407 | if (bp && !bp->attr.disabled) { |
| 408 | dump->u_debugreg[i] = bp->attr.bp_addr; |
| 409 | info = counter_arch_bp(bp); |
| 410 | dr7 |= encode_dr7(i, info->len, info->type); |
| 411 | } else { |
| 412 | dump->u_debugreg[i] = 0; |
| 413 | } |
| 414 | } |
| 415 | |
| 416 | dump->u_debugreg[4] = 0; |
| 417 | dump->u_debugreg[5] = 0; |
| 418 | dump->u_debugreg[6] = current->thread.debugreg6; |
| 419 | |
| 420 | dump->u_debugreg[7] = dr7; |
| 421 | } |
Ingo Molnar | 68efa37 | 2009-11-14 01:35:29 +0100 | [diff] [blame] | 422 | EXPORT_SYMBOL_GPL(aout_dump_debugregs); |
Frederic Weisbecker | 9f6b3c2 | 2009-11-09 21:03:43 +0100 | [diff] [blame] | 423 | |
| 424 | /* |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 425 | * Release the user breakpoints used by ptrace |
| 426 | */ |
| 427 | void flush_ptrace_hw_breakpoint(struct task_struct *tsk) |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 428 | { |
| 429 | int i; |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 430 | struct thread_struct *t = &tsk->thread; |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 431 | |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 432 | for (i = 0; i < HBP_NUM; i++) { |
| 433 | unregister_hw_breakpoint(t->ptrace_bps[i]); |
| 434 | t->ptrace_bps[i] = NULL; |
| 435 | } |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 436 | } |
| 437 | |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 438 | void hw_breakpoint_restore(void) |
| 439 | { |
| 440 | set_debugreg(__get_cpu_var(cpu_debugreg[0]), 0); |
| 441 | set_debugreg(__get_cpu_var(cpu_debugreg[1]), 1); |
| 442 | set_debugreg(__get_cpu_var(cpu_debugreg[2]), 2); |
| 443 | set_debugreg(__get_cpu_var(cpu_debugreg[3]), 3); |
| 444 | set_debugreg(current->thread.debugreg6, 6); |
Tejun Heo | 28b4e0d | 2009-11-25 22:24:44 +0900 | [diff] [blame] | 445 | set_debugreg(__get_cpu_var(cpu_dr7), 7); |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 446 | } |
| 447 | EXPORT_SYMBOL_GPL(hw_breakpoint_restore); |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 448 | |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 449 | /* |
| 450 | * Handle debug exception notifications. |
| 451 | * |
| 452 | * Return value is either NOTIFY_STOP or NOTIFY_DONE as explained below. |
| 453 | * |
| 454 | * NOTIFY_DONE returned if one of the following conditions is true. |
| 455 | * i) When the causative address is from user-space and the exception |
| 456 | * is a valid one, i.e. not triggered as a result of lazy debug register |
| 457 | * switching |
| 458 | * ii) When there are more bits than trap<n> set in DR6 register (such |
| 459 | * as BD, BS or BT) indicating that more than one debug condition is |
| 460 | * met and requires some more action in do_debug(). |
| 461 | * |
| 462 | * NOTIFY_STOP returned for all other cases |
| 463 | * |
| 464 | */ |
Jaswinder Singh Rajput | 4555835 | 2009-06-17 14:44:19 +0530 | [diff] [blame] | 465 | static int __kprobes hw_breakpoint_handler(struct die_args *args) |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 466 | { |
| 467 | int i, cpu, rc = NOTIFY_STOP; |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 468 | struct perf_event *bp; |
K.Prasad | 62edab9 | 2009-06-01 23:47:06 +0530 | [diff] [blame] | 469 | unsigned long dr7, dr6; |
| 470 | unsigned long *dr6_p; |
| 471 | |
| 472 | /* The DR6 value is pointed by args->err */ |
| 473 | dr6_p = (unsigned long *)ERR_PTR(args->err); |
| 474 | dr6 = *dr6_p; |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 475 | |
| 476 | /* Do an early return if no trap bits are set in DR6 */ |
| 477 | if ((dr6 & DR_TRAP_BITS) == 0) |
| 478 | return NOTIFY_DONE; |
| 479 | |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 480 | get_debugreg(dr7, 7); |
| 481 | /* Disable breakpoints during exception handling */ |
| 482 | set_debugreg(0UL, 7); |
| 483 | /* |
| 484 | * Assert that local interrupts are disabled |
| 485 | * Reset the DRn bits in the virtualized register value. |
| 486 | * The ptrace trigger routine will add in whatever is needed. |
| 487 | */ |
| 488 | current->thread.debugreg6 &= ~DR_TRAP_BITS; |
| 489 | cpu = get_cpu(); |
| 490 | |
| 491 | /* Handle all the breakpoints that were triggered */ |
| 492 | for (i = 0; i < HBP_NUM; ++i) { |
| 493 | if (likely(!(dr6 & (DR_TRAP0 << i)))) |
| 494 | continue; |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 495 | |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 496 | /* |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 497 | * The counter may be concurrently released but that can only |
| 498 | * occur from a call_rcu() path. We can then safely fetch |
| 499 | * the breakpoint, use its callback, touch its counter |
| 500 | * while we are in an rcu_read_lock() path. |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 501 | */ |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 502 | rcu_read_lock(); |
| 503 | |
| 504 | bp = per_cpu(bp_per_reg[i], cpu); |
| 505 | if (bp) |
| 506 | rc = NOTIFY_DONE; |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 507 | /* |
K.Prasad | 62edab9 | 2009-06-01 23:47:06 +0530 | [diff] [blame] | 508 | * Reset the 'i'th TRAP bit in dr6 to denote completion of |
| 509 | * exception handling |
| 510 | */ |
| 511 | (*dr6_p) &= ~(DR_TRAP0 << i); |
| 512 | /* |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 513 | * bp can be NULL due to lazy debug register switching |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 514 | * or due to concurrent perf counter removing. |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 515 | */ |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 516 | if (!bp) { |
| 517 | rcu_read_unlock(); |
| 518 | break; |
| 519 | } |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 520 | |
Frederic Weisbecker | b326e95 | 2009-12-05 09:44:31 +0100 | [diff] [blame] | 521 | perf_bp_event(bp, args->regs); |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 522 | |
| 523 | rcu_read_unlock(); |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 524 | } |
| 525 | if (dr6 & (~DR_TRAP_BITS)) |
| 526 | rc = NOTIFY_DONE; |
| 527 | |
| 528 | set_debugreg(dr7, 7); |
Ingo Molnar | eadb8a0 | 2009-06-17 12:52:15 +0200 | [diff] [blame] | 529 | put_cpu(); |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 530 | |
K.Prasad | 0067f12 | 2009-06-01 23:43:57 +0530 | [diff] [blame] | 531 | return rc; |
| 532 | } |
| 533 | |
| 534 | /* |
| 535 | * Handle debug exception notifications. |
| 536 | */ |
| 537 | int __kprobes hw_breakpoint_exceptions_notify( |
| 538 | struct notifier_block *unused, unsigned long val, void *data) |
| 539 | { |
| 540 | if (val != DIE_DEBUG) |
| 541 | return NOTIFY_DONE; |
| 542 | |
| 543 | return hw_breakpoint_handler(data); |
| 544 | } |
Frederic Weisbecker | 24f1e32c | 2009-09-09 19:22:48 +0200 | [diff] [blame] | 545 | |
| 546 | void hw_breakpoint_pmu_read(struct perf_event *bp) |
| 547 | { |
| 548 | /* TODO */ |
| 549 | } |
| 550 | |
| 551 | void hw_breakpoint_pmu_unthrottle(struct perf_event *bp) |
| 552 | { |
| 553 | /* TODO */ |
| 554 | } |