Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 1 | /* |
| 2 | * ARMv8 single-step debug support and mdscr context switching. |
| 3 | * |
| 4 | * Copyright (C) 2012 ARM Limited |
| 5 | * |
| 6 | * This program is free software; you can redistribute it and/or modify |
| 7 | * it under the terms of the GNU General Public License version 2 as |
| 8 | * published by the Free Software Foundation. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU General Public License for more details. |
| 14 | * |
| 15 | * You should have received a copy of the GNU General Public License |
| 16 | * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 17 | * |
| 18 | * Author: Will Deacon <will.deacon@arm.com> |
| 19 | */ |
| 20 | |
| 21 | #include <linux/cpu.h> |
| 22 | #include <linux/debugfs.h> |
| 23 | #include <linux/hardirq.h> |
| 24 | #include <linux/init.h> |
| 25 | #include <linux/ptrace.h> |
Sandeepa Prabhu | 2dd0e8d | 2016-07-08 12:35:48 -0400 | [diff] [blame] | 26 | #include <linux/kprobes.h> |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 27 | #include <linux/stat.h> |
Will Deacon | 1442b6e | 2013-03-16 08:48:13 +0000 | [diff] [blame] | 28 | #include <linux/uaccess.h> |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 29 | |
Suzuki K. Poulose | 3085bb0 | 2015-10-19 14:24:54 +0100 | [diff] [blame] | 30 | #include <asm/cpufeature.h> |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 31 | #include <asm/cputype.h> |
Suzuki K. Poulose | 3085bb0 | 2015-10-19 14:24:54 +0100 | [diff] [blame] | 32 | #include <asm/debug-monitors.h> |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 33 | #include <asm/system_misc.h> |
| 34 | |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 35 | /* Determine debug architecture. */ |
| 36 | u8 debug_monitors_arch(void) |
| 37 | { |
Suzuki K Poulose | 28c5dcb | 2016-01-26 10:58:16 +0000 | [diff] [blame] | 38 | return cpuid_feature_extract_unsigned_field(read_system_reg(SYS_ID_AA64DFR0_EL1), |
Suzuki K. Poulose | 3085bb0 | 2015-10-19 14:24:54 +0100 | [diff] [blame] | 39 | ID_AA64DFR0_DEBUGVER_SHIFT); |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 40 | } |
| 41 | |
| 42 | /* |
| 43 | * MDSCR access routines. |
| 44 | */ |
| 45 | static void mdscr_write(u32 mdscr) |
| 46 | { |
| 47 | unsigned long flags; |
| 48 | local_dbg_save(flags); |
Mark Rutland | adf7589 | 2016-09-08 13:55:38 +0100 | [diff] [blame] | 49 | write_sysreg(mdscr, mdscr_el1); |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 50 | local_dbg_restore(flags); |
| 51 | } |
Pratyush Anand | 44b53f6 | 2016-07-08 12:35:49 -0400 | [diff] [blame] | 52 | NOKPROBE_SYMBOL(mdscr_write); |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 53 | |
| 54 | static u32 mdscr_read(void) |
| 55 | { |
Mark Rutland | adf7589 | 2016-09-08 13:55:38 +0100 | [diff] [blame] | 56 | return read_sysreg(mdscr_el1); |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 57 | } |
Pratyush Anand | 44b53f6 | 2016-07-08 12:35:49 -0400 | [diff] [blame] | 58 | NOKPROBE_SYMBOL(mdscr_read); |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 59 | |
| 60 | /* |
| 61 | * Allow root to disable self-hosted debug from userspace. |
| 62 | * This is useful if you want to connect an external JTAG debugger. |
| 63 | */ |
Viresh Kumar | 621a5f7 | 2015-09-26 15:04:07 -0700 | [diff] [blame] | 64 | static bool debug_enabled = true; |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 65 | |
| 66 | static int create_debug_debugfs_entry(void) |
| 67 | { |
| 68 | debugfs_create_bool("debug_enabled", 0644, NULL, &debug_enabled); |
| 69 | return 0; |
| 70 | } |
| 71 | fs_initcall(create_debug_debugfs_entry); |
| 72 | |
| 73 | static int __init early_debug_disable(char *buf) |
| 74 | { |
Viresh Kumar | 621a5f7 | 2015-09-26 15:04:07 -0700 | [diff] [blame] | 75 | debug_enabled = false; |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 76 | return 0; |
| 77 | } |
| 78 | |
| 79 | early_param("nodebugmon", early_debug_disable); |
| 80 | |
| 81 | /* |
| 82 | * Keep track of debug users on each core. |
| 83 | * The ref counts are per-cpu so we use a local_t type. |
| 84 | */ |
Christoph Lameter | 1436c1a | 2013-10-21 13:17:08 +0100 | [diff] [blame] | 85 | static DEFINE_PER_CPU(int, mde_ref_count); |
| 86 | static DEFINE_PER_CPU(int, kde_ref_count); |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 87 | |
Will Deacon | 6f883d1 | 2015-07-27 18:36:54 +0100 | [diff] [blame] | 88 | void enable_debug_monitors(enum dbg_active_el el) |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 89 | { |
| 90 | u32 mdscr, enable = 0; |
| 91 | |
| 92 | WARN_ON(preemptible()); |
| 93 | |
Christoph Lameter | 1436c1a | 2013-10-21 13:17:08 +0100 | [diff] [blame] | 94 | if (this_cpu_inc_return(mde_ref_count) == 1) |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 95 | enable = DBG_MDSCR_MDE; |
| 96 | |
| 97 | if (el == DBG_ACTIVE_EL1 && |
Christoph Lameter | 1436c1a | 2013-10-21 13:17:08 +0100 | [diff] [blame] | 98 | this_cpu_inc_return(kde_ref_count) == 1) |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 99 | enable |= DBG_MDSCR_KDE; |
| 100 | |
| 101 | if (enable && debug_enabled) { |
| 102 | mdscr = mdscr_read(); |
| 103 | mdscr |= enable; |
| 104 | mdscr_write(mdscr); |
| 105 | } |
| 106 | } |
Pratyush Anand | 44b53f6 | 2016-07-08 12:35:49 -0400 | [diff] [blame] | 107 | NOKPROBE_SYMBOL(enable_debug_monitors); |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 108 | |
Will Deacon | 6f883d1 | 2015-07-27 18:36:54 +0100 | [diff] [blame] | 109 | void disable_debug_monitors(enum dbg_active_el el) |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 110 | { |
| 111 | u32 mdscr, disable = 0; |
| 112 | |
| 113 | WARN_ON(preemptible()); |
| 114 | |
Christoph Lameter | 1436c1a | 2013-10-21 13:17:08 +0100 | [diff] [blame] | 115 | if (this_cpu_dec_return(mde_ref_count) == 0) |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 116 | disable = ~DBG_MDSCR_MDE; |
| 117 | |
| 118 | if (el == DBG_ACTIVE_EL1 && |
Christoph Lameter | 1436c1a | 2013-10-21 13:17:08 +0100 | [diff] [blame] | 119 | this_cpu_dec_return(kde_ref_count) == 0) |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 120 | disable &= ~DBG_MDSCR_KDE; |
| 121 | |
| 122 | if (disable) { |
| 123 | mdscr = mdscr_read(); |
| 124 | mdscr &= disable; |
| 125 | mdscr_write(mdscr); |
| 126 | } |
| 127 | } |
Pratyush Anand | 44b53f6 | 2016-07-08 12:35:49 -0400 | [diff] [blame] | 128 | NOKPROBE_SYMBOL(disable_debug_monitors); |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 129 | |
| 130 | /* |
| 131 | * OS lock clearing. |
| 132 | */ |
Will Deacon | e937dd5 | 2016-08-16 11:29:17 +0100 | [diff] [blame] | 133 | static int clear_os_lock(unsigned int cpu) |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 134 | { |
Mark Rutland | adf7589 | 2016-09-08 13:55:38 +0100 | [diff] [blame] | 135 | write_sysreg(0, oslar_el1); |
Will Deacon | e937dd5 | 2016-08-16 11:29:17 +0100 | [diff] [blame] | 136 | isb(); |
| 137 | return 0; |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 138 | } |
| 139 | |
Paul Gortmaker | b8c6453 | 2013-06-18 10:18:31 -0400 | [diff] [blame] | 140 | static int debug_monitors_init(void) |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 141 | { |
Will Deacon | e937dd5 | 2016-08-16 11:29:17 +0100 | [diff] [blame] | 142 | return cpuhp_setup_state(CPUHP_AP_ARM64_DEBUG_MONITORS_STARTING, |
| 143 | "CPUHP_AP_ARM64_DEBUG_MONITORS_STARTING", |
| 144 | clear_os_lock, NULL); |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 145 | } |
| 146 | postcore_initcall(debug_monitors_init); |
| 147 | |
| 148 | /* |
| 149 | * Single step API and exception handling. |
| 150 | */ |
| 151 | static void set_regs_spsr_ss(struct pt_regs *regs) |
| 152 | { |
Will Deacon | 6b68e14 | 2016-07-19 15:07:38 +0100 | [diff] [blame] | 153 | regs->pstate |= DBG_SPSR_SS; |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 154 | } |
Pratyush Anand | 44b53f6 | 2016-07-08 12:35:49 -0400 | [diff] [blame] | 155 | NOKPROBE_SYMBOL(set_regs_spsr_ss); |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 156 | |
| 157 | static void clear_regs_spsr_ss(struct pt_regs *regs) |
| 158 | { |
Will Deacon | 6b68e14 | 2016-07-19 15:07:38 +0100 | [diff] [blame] | 159 | regs->pstate &= ~DBG_SPSR_SS; |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 160 | } |
Pratyush Anand | 44b53f6 | 2016-07-08 12:35:49 -0400 | [diff] [blame] | 161 | NOKPROBE_SYMBOL(clear_regs_spsr_ss); |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 162 | |
Sandeepa Prabhu | ee6214c | 2013-12-04 05:50:20 +0000 | [diff] [blame] | 163 | /* EL1 Single Step Handler hooks */ |
| 164 | static LIST_HEAD(step_hook); |
Yang Shi | cf0a254 | 2016-02-08 14:49:24 -0800 | [diff] [blame] | 165 | static DEFINE_SPINLOCK(step_hook_lock); |
Sandeepa Prabhu | ee6214c | 2013-12-04 05:50:20 +0000 | [diff] [blame] | 166 | |
| 167 | void register_step_hook(struct step_hook *hook) |
| 168 | { |
Yang Shi | cf0a254 | 2016-02-08 14:49:24 -0800 | [diff] [blame] | 169 | spin_lock(&step_hook_lock); |
| 170 | list_add_rcu(&hook->node, &step_hook); |
| 171 | spin_unlock(&step_hook_lock); |
Sandeepa Prabhu | ee6214c | 2013-12-04 05:50:20 +0000 | [diff] [blame] | 172 | } |
| 173 | |
| 174 | void unregister_step_hook(struct step_hook *hook) |
| 175 | { |
Yang Shi | cf0a254 | 2016-02-08 14:49:24 -0800 | [diff] [blame] | 176 | spin_lock(&step_hook_lock); |
| 177 | list_del_rcu(&hook->node); |
| 178 | spin_unlock(&step_hook_lock); |
| 179 | synchronize_rcu(); |
Sandeepa Prabhu | ee6214c | 2013-12-04 05:50:20 +0000 | [diff] [blame] | 180 | } |
| 181 | |
| 182 | /* |
Yang Shi | 95485fd | 2015-09-18 22:09:00 +0100 | [diff] [blame] | 183 | * Call registered single step handlers |
Sandeepa Prabhu | ee6214c | 2013-12-04 05:50:20 +0000 | [diff] [blame] | 184 | * There is no Syndrome info to check for determining the handler. |
| 185 | * So we call all the registered handlers, until the right handler is |
| 186 | * found which returns zero. |
| 187 | */ |
| 188 | static int call_step_hook(struct pt_regs *regs, unsigned int esr) |
| 189 | { |
| 190 | struct step_hook *hook; |
| 191 | int retval = DBG_HOOK_ERROR; |
| 192 | |
Yang Shi | cf0a254 | 2016-02-08 14:49:24 -0800 | [diff] [blame] | 193 | rcu_read_lock(); |
Sandeepa Prabhu | ee6214c | 2013-12-04 05:50:20 +0000 | [diff] [blame] | 194 | |
Yang Shi | cf0a254 | 2016-02-08 14:49:24 -0800 | [diff] [blame] | 195 | list_for_each_entry_rcu(hook, &step_hook, node) { |
Sandeepa Prabhu | ee6214c | 2013-12-04 05:50:20 +0000 | [diff] [blame] | 196 | retval = hook->fn(regs, esr); |
| 197 | if (retval == DBG_HOOK_HANDLED) |
| 198 | break; |
| 199 | } |
| 200 | |
Yang Shi | cf0a254 | 2016-02-08 14:49:24 -0800 | [diff] [blame] | 201 | rcu_read_unlock(); |
Sandeepa Prabhu | ee6214c | 2013-12-04 05:50:20 +0000 | [diff] [blame] | 202 | |
| 203 | return retval; |
| 204 | } |
Pratyush Anand | 44b53f6 | 2016-07-08 12:35:49 -0400 | [diff] [blame] | 205 | NOKPROBE_SYMBOL(call_step_hook); |
Sandeepa Prabhu | ee6214c | 2013-12-04 05:50:20 +0000 | [diff] [blame] | 206 | |
Will Deacon | e04a28d | 2016-02-10 16:05:28 +0000 | [diff] [blame] | 207 | static void send_user_sigtrap(int si_code) |
| 208 | { |
| 209 | struct pt_regs *regs = current_pt_regs(); |
| 210 | siginfo_t info = { |
| 211 | .si_signo = SIGTRAP, |
| 212 | .si_errno = 0, |
| 213 | .si_code = si_code, |
| 214 | .si_addr = (void __user *)instruction_pointer(regs), |
| 215 | }; |
| 216 | |
| 217 | if (WARN_ON(!user_mode(regs))) |
| 218 | return; |
| 219 | |
| 220 | if (interrupts_enabled(regs)) |
| 221 | local_irq_enable(); |
| 222 | |
| 223 | force_sig_info(SIGTRAP, &info, current); |
| 224 | } |
| 225 | |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 226 | static int single_step_handler(unsigned long addr, unsigned int esr, |
| 227 | struct pt_regs *regs) |
| 228 | { |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 229 | /* |
| 230 | * If we are stepping a pending breakpoint, call the hw_breakpoint |
| 231 | * handler first. |
| 232 | */ |
| 233 | if (!reinstall_suspended_bps(regs)) |
| 234 | return 0; |
| 235 | |
| 236 | if (user_mode(regs)) { |
Will Deacon | adeb68e | 2016-09-01 13:35:02 +0100 | [diff] [blame] | 237 | send_user_sigtrap(TRAP_TRACE); |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 238 | |
| 239 | /* |
| 240 | * ptrace will disable single step unless explicitly |
| 241 | * asked to re-enable it. For other clients, it makes |
| 242 | * sense to leave it enabled (i.e. rewind the controls |
| 243 | * to the active-not-pending state). |
| 244 | */ |
| 245 | user_rewind_single_step(current); |
| 246 | } else { |
Sandeepa Prabhu | 2dd0e8d | 2016-07-08 12:35:48 -0400 | [diff] [blame] | 247 | #ifdef CONFIG_KPROBES |
| 248 | if (kprobe_single_step_handler(regs, esr) == DBG_HOOK_HANDLED) |
| 249 | return 0; |
| 250 | #endif |
Sandeepa Prabhu | ee6214c | 2013-12-04 05:50:20 +0000 | [diff] [blame] | 251 | if (call_step_hook(regs, esr) == DBG_HOOK_HANDLED) |
| 252 | return 0; |
| 253 | |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 254 | pr_warning("Unexpected kernel single-step exception at EL1\n"); |
| 255 | /* |
| 256 | * Re-enable stepping since we know that we will be |
| 257 | * returning to regs. |
| 258 | */ |
| 259 | set_regs_spsr_ss(regs); |
| 260 | } |
| 261 | |
| 262 | return 0; |
| 263 | } |
Pratyush Anand | 44b53f6 | 2016-07-08 12:35:49 -0400 | [diff] [blame] | 264 | NOKPROBE_SYMBOL(single_step_handler); |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 265 | |
Sandeepa Prabhu | ee6214c | 2013-12-04 05:50:20 +0000 | [diff] [blame] | 266 | /* |
| 267 | * Breakpoint handler is re-entrant as another breakpoint can |
| 268 | * hit within breakpoint handler, especically in kprobes. |
| 269 | * Use reader/writer locks instead of plain spinlock. |
| 270 | */ |
| 271 | static LIST_HEAD(break_hook); |
Yang Shi | 62c6c61 | 2015-10-05 14:32:51 -0700 | [diff] [blame] | 272 | static DEFINE_SPINLOCK(break_hook_lock); |
Sandeepa Prabhu | ee6214c | 2013-12-04 05:50:20 +0000 | [diff] [blame] | 273 | |
| 274 | void register_break_hook(struct break_hook *hook) |
| 275 | { |
Yang Shi | 62c6c61 | 2015-10-05 14:32:51 -0700 | [diff] [blame] | 276 | spin_lock(&break_hook_lock); |
| 277 | list_add_rcu(&hook->node, &break_hook); |
| 278 | spin_unlock(&break_hook_lock); |
Sandeepa Prabhu | ee6214c | 2013-12-04 05:50:20 +0000 | [diff] [blame] | 279 | } |
| 280 | |
| 281 | void unregister_break_hook(struct break_hook *hook) |
| 282 | { |
Yang Shi | 62c6c61 | 2015-10-05 14:32:51 -0700 | [diff] [blame] | 283 | spin_lock(&break_hook_lock); |
| 284 | list_del_rcu(&hook->node); |
| 285 | spin_unlock(&break_hook_lock); |
| 286 | synchronize_rcu(); |
Sandeepa Prabhu | ee6214c | 2013-12-04 05:50:20 +0000 | [diff] [blame] | 287 | } |
| 288 | |
| 289 | static int call_break_hook(struct pt_regs *regs, unsigned int esr) |
| 290 | { |
| 291 | struct break_hook *hook; |
| 292 | int (*fn)(struct pt_regs *regs, unsigned int esr) = NULL; |
| 293 | |
Yang Shi | 62c6c61 | 2015-10-05 14:32:51 -0700 | [diff] [blame] | 294 | rcu_read_lock(); |
| 295 | list_for_each_entry_rcu(hook, &break_hook, node) |
Sandeepa Prabhu | ee6214c | 2013-12-04 05:50:20 +0000 | [diff] [blame] | 296 | if ((esr & hook->esr_mask) == hook->esr_val) |
| 297 | fn = hook->fn; |
Yang Shi | 62c6c61 | 2015-10-05 14:32:51 -0700 | [diff] [blame] | 298 | rcu_read_unlock(); |
Sandeepa Prabhu | ee6214c | 2013-12-04 05:50:20 +0000 | [diff] [blame] | 299 | |
| 300 | return fn ? fn(regs, esr) : DBG_HOOK_ERROR; |
| 301 | } |
Pratyush Anand | 44b53f6 | 2016-07-08 12:35:49 -0400 | [diff] [blame] | 302 | NOKPROBE_SYMBOL(call_break_hook); |
Sandeepa Prabhu | ee6214c | 2013-12-04 05:50:20 +0000 | [diff] [blame] | 303 | |
Will Deacon | 1442b6e | 2013-03-16 08:48:13 +0000 | [diff] [blame] | 304 | static int brk_handler(unsigned long addr, unsigned int esr, |
| 305 | struct pt_regs *regs) |
| 306 | { |
Will Deacon | c878e0c | 2014-07-31 11:36:08 +0100 | [diff] [blame] | 307 | if (user_mode(regs)) { |
Will Deacon | e04a28d | 2016-02-10 16:05:28 +0000 | [diff] [blame] | 308 | send_user_sigtrap(TRAP_BRKPT); |
Sandeepa Prabhu | 2dd0e8d | 2016-07-08 12:35:48 -0400 | [diff] [blame] | 309 | } |
| 310 | #ifdef CONFIG_KPROBES |
| 311 | else if ((esr & BRK64_ESR_MASK) == BRK64_ESR_KPROBES) { |
| 312 | if (kprobe_breakpoint_handler(regs, esr) != DBG_HOOK_HANDLED) |
| 313 | return -EFAULT; |
| 314 | } |
| 315 | #endif |
| 316 | else if (call_break_hook(regs, esr) != DBG_HOOK_HANDLED) { |
| 317 | pr_warn("Unexpected kernel BRK exception at EL1\n"); |
Will Deacon | 1442b6e | 2013-03-16 08:48:13 +0000 | [diff] [blame] | 318 | return -EFAULT; |
Will Deacon | c878e0c | 2014-07-31 11:36:08 +0100 | [diff] [blame] | 319 | } |
Will Deacon | 1442b6e | 2013-03-16 08:48:13 +0000 | [diff] [blame] | 320 | |
Will Deacon | 1442b6e | 2013-03-16 08:48:13 +0000 | [diff] [blame] | 321 | return 0; |
| 322 | } |
Pratyush Anand | 44b53f6 | 2016-07-08 12:35:49 -0400 | [diff] [blame] | 323 | NOKPROBE_SYMBOL(brk_handler); |
Will Deacon | 1442b6e | 2013-03-16 08:48:13 +0000 | [diff] [blame] | 324 | |
| 325 | int aarch32_break_handler(struct pt_regs *regs) |
| 326 | { |
Matthew Leach | 2dacab7 | 2013-11-28 12:07:23 +0000 | [diff] [blame] | 327 | u32 arm_instr; |
| 328 | u16 thumb_instr; |
Will Deacon | 1442b6e | 2013-03-16 08:48:13 +0000 | [diff] [blame] | 329 | bool bp = false; |
| 330 | void __user *pc = (void __user *)instruction_pointer(regs); |
| 331 | |
| 332 | if (!compat_user_mode(regs)) |
| 333 | return -EFAULT; |
| 334 | |
| 335 | if (compat_thumb_mode(regs)) { |
| 336 | /* get 16-bit Thumb instruction */ |
Matthew Leach | 2dacab7 | 2013-11-28 12:07:23 +0000 | [diff] [blame] | 337 | get_user(thumb_instr, (u16 __user *)pc); |
| 338 | thumb_instr = le16_to_cpu(thumb_instr); |
| 339 | if (thumb_instr == AARCH32_BREAK_THUMB2_LO) { |
Will Deacon | 1442b6e | 2013-03-16 08:48:13 +0000 | [diff] [blame] | 340 | /* get second half of 32-bit Thumb-2 instruction */ |
Matthew Leach | 2dacab7 | 2013-11-28 12:07:23 +0000 | [diff] [blame] | 341 | get_user(thumb_instr, (u16 __user *)(pc + 2)); |
| 342 | thumb_instr = le16_to_cpu(thumb_instr); |
| 343 | bp = thumb_instr == AARCH32_BREAK_THUMB2_HI; |
Will Deacon | 1442b6e | 2013-03-16 08:48:13 +0000 | [diff] [blame] | 344 | } else { |
Matthew Leach | 2dacab7 | 2013-11-28 12:07:23 +0000 | [diff] [blame] | 345 | bp = thumb_instr == AARCH32_BREAK_THUMB; |
Will Deacon | 1442b6e | 2013-03-16 08:48:13 +0000 | [diff] [blame] | 346 | } |
| 347 | } else { |
| 348 | /* 32-bit ARM instruction */ |
Matthew Leach | 2dacab7 | 2013-11-28 12:07:23 +0000 | [diff] [blame] | 349 | get_user(arm_instr, (u32 __user *)pc); |
| 350 | arm_instr = le32_to_cpu(arm_instr); |
| 351 | bp = (arm_instr & ~0xf0000000) == AARCH32_BREAK_ARM; |
Will Deacon | 1442b6e | 2013-03-16 08:48:13 +0000 | [diff] [blame] | 352 | } |
| 353 | |
| 354 | if (!bp) |
| 355 | return -EFAULT; |
| 356 | |
Will Deacon | e04a28d | 2016-02-10 16:05:28 +0000 | [diff] [blame] | 357 | send_user_sigtrap(TRAP_BRKPT); |
Will Deacon | 1442b6e | 2013-03-16 08:48:13 +0000 | [diff] [blame] | 358 | return 0; |
| 359 | } |
Pratyush Anand | 44b53f6 | 2016-07-08 12:35:49 -0400 | [diff] [blame] | 360 | NOKPROBE_SYMBOL(aarch32_break_handler); |
Will Deacon | 1442b6e | 2013-03-16 08:48:13 +0000 | [diff] [blame] | 361 | |
| 362 | static int __init debug_traps_init(void) |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 363 | { |
| 364 | hook_debug_fault_code(DBG_ESR_EVT_HWSS, single_step_handler, SIGTRAP, |
Will Deacon | adeb68e | 2016-09-01 13:35:02 +0100 | [diff] [blame] | 365 | TRAP_TRACE, "single-step handler"); |
Will Deacon | 1442b6e | 2013-03-16 08:48:13 +0000 | [diff] [blame] | 366 | hook_debug_fault_code(DBG_ESR_EVT_BRK, brk_handler, SIGTRAP, |
| 367 | TRAP_BRKPT, "ptrace BRK handler"); |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 368 | return 0; |
| 369 | } |
Will Deacon | 1442b6e | 2013-03-16 08:48:13 +0000 | [diff] [blame] | 370 | arch_initcall(debug_traps_init); |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 371 | |
| 372 | /* Re-enable single step for syscall restarting. */ |
| 373 | void user_rewind_single_step(struct task_struct *task) |
| 374 | { |
| 375 | /* |
| 376 | * If single step is active for this thread, then set SPSR.SS |
| 377 | * to 1 to avoid returning to the active-pending state. |
| 378 | */ |
| 379 | if (test_ti_thread_flag(task_thread_info(task), TIF_SINGLESTEP)) |
| 380 | set_regs_spsr_ss(task_pt_regs(task)); |
| 381 | } |
Pratyush Anand | 44b53f6 | 2016-07-08 12:35:49 -0400 | [diff] [blame] | 382 | NOKPROBE_SYMBOL(user_rewind_single_step); |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 383 | |
| 384 | void user_fastforward_single_step(struct task_struct *task) |
| 385 | { |
| 386 | if (test_ti_thread_flag(task_thread_info(task), TIF_SINGLESTEP)) |
| 387 | clear_regs_spsr_ss(task_pt_regs(task)); |
| 388 | } |
| 389 | |
| 390 | /* Kernel API */ |
| 391 | void kernel_enable_single_step(struct pt_regs *regs) |
| 392 | { |
| 393 | WARN_ON(!irqs_disabled()); |
| 394 | set_regs_spsr_ss(regs); |
| 395 | mdscr_write(mdscr_read() | DBG_MDSCR_SS); |
| 396 | enable_debug_monitors(DBG_ACTIVE_EL1); |
| 397 | } |
Pratyush Anand | 44b53f6 | 2016-07-08 12:35:49 -0400 | [diff] [blame] | 398 | NOKPROBE_SYMBOL(kernel_enable_single_step); |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 399 | |
| 400 | void kernel_disable_single_step(void) |
| 401 | { |
| 402 | WARN_ON(!irqs_disabled()); |
| 403 | mdscr_write(mdscr_read() & ~DBG_MDSCR_SS); |
| 404 | disable_debug_monitors(DBG_ACTIVE_EL1); |
| 405 | } |
Pratyush Anand | 44b53f6 | 2016-07-08 12:35:49 -0400 | [diff] [blame] | 406 | NOKPROBE_SYMBOL(kernel_disable_single_step); |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 407 | |
| 408 | int kernel_active_single_step(void) |
| 409 | { |
| 410 | WARN_ON(!irqs_disabled()); |
| 411 | return mdscr_read() & DBG_MDSCR_SS; |
| 412 | } |
Pratyush Anand | 44b53f6 | 2016-07-08 12:35:49 -0400 | [diff] [blame] | 413 | NOKPROBE_SYMBOL(kernel_active_single_step); |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 414 | |
| 415 | /* ptrace API */ |
| 416 | void user_enable_single_step(struct task_struct *task) |
| 417 | { |
Will Deacon | 3a402a7 | 2016-08-26 11:36:39 +0100 | [diff] [blame] | 418 | struct thread_info *ti = task_thread_info(task); |
| 419 | |
| 420 | if (!test_and_set_ti_thread_flag(ti, TIF_SINGLESTEP)) |
| 421 | set_regs_spsr_ss(task_pt_regs(task)); |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 422 | } |
Pratyush Anand | 44b53f6 | 2016-07-08 12:35:49 -0400 | [diff] [blame] | 423 | NOKPROBE_SYMBOL(user_enable_single_step); |
Will Deacon | 478fcb2 | 2012-03-05 11:49:33 +0000 | [diff] [blame] | 424 | |
| 425 | void user_disable_single_step(struct task_struct *task) |
| 426 | { |
| 427 | clear_ti_thread_flag(task_thread_info(task), TIF_SINGLESTEP); |
| 428 | } |
Pratyush Anand | 44b53f6 | 2016-07-08 12:35:49 -0400 | [diff] [blame] | 429 | NOKPROBE_SYMBOL(user_disable_single_step); |