diff options
author | Sandeepa Prabhu <sandeepa.prabhu@linaro.org> | 2013-12-04 00:50:20 -0500 |
---|---|---|
committer | Catalin Marinas <catalin.marinas@arm.com> | 2013-12-19 12:43:11 -0500 |
commit | ee6214cec7818867f368c35843ea1f3dffcbb57c (patch) | |
tree | dc85030cc4fee90004063af8401489f5091af3a6 /arch/arm64/kernel/debug-monitors.c | |
parent | 26920dd2da79a3207803da9453c0e6c82ac968ca (diff) |
arm64: support single-step and breakpoint handler hooks
AArch64 Single Steping and Breakpoint debug exceptions will be
used by multiple debug framworks like kprobes & kgdb.
This patch implements the hooks for those frameworks to register
their own handlers for handling breakpoint and single step events.
Reworked the debug exception handler in entry.S: do_dbg to route
software breakpoint (BRK64) exception to do_debug_exception()
Signed-off-by: Sandeepa Prabhu <sandeepa.prabhu@linaro.org>
Signed-off-by: Deepak Saxena <dsaxena@linaro.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Diffstat (limited to 'arch/arm64/kernel/debug-monitors.c')
-rw-r--r-- | arch/arm64/kernel/debug-monitors.c | 88 |
1 files changed, 87 insertions, 1 deletions
diff --git a/arch/arm64/kernel/debug-monitors.c b/arch/arm64/kernel/debug-monitors.c index 4ae68579031d..636ba8b6240b 100644 --- a/arch/arm64/kernel/debug-monitors.c +++ b/arch/arm64/kernel/debug-monitors.c | |||
@@ -187,6 +187,48 @@ static void clear_regs_spsr_ss(struct pt_regs *regs) | |||
187 | regs->pstate = spsr; | 187 | regs->pstate = spsr; |
188 | } | 188 | } |
189 | 189 | ||
190 | /* EL1 Single Step Handler hooks */ | ||
191 | static LIST_HEAD(step_hook); | ||
192 | DEFINE_RWLOCK(step_hook_lock); | ||
193 | |||
194 | void register_step_hook(struct step_hook *hook) | ||
195 | { | ||
196 | write_lock(&step_hook_lock); | ||
197 | list_add(&hook->node, &step_hook); | ||
198 | write_unlock(&step_hook_lock); | ||
199 | } | ||
200 | |||
201 | void unregister_step_hook(struct step_hook *hook) | ||
202 | { | ||
203 | write_lock(&step_hook_lock); | ||
204 | list_del(&hook->node); | ||
205 | write_unlock(&step_hook_lock); | ||
206 | } | ||
207 | |||
208 | /* | ||
209 | * Call registered single step handers | ||
210 | * There is no Syndrome info to check for determining the handler. | ||
211 | * So we call all the registered handlers, until the right handler is | ||
212 | * found which returns zero. | ||
213 | */ | ||
214 | static int call_step_hook(struct pt_regs *regs, unsigned int esr) | ||
215 | { | ||
216 | struct step_hook *hook; | ||
217 | int retval = DBG_HOOK_ERROR; | ||
218 | |||
219 | read_lock(&step_hook_lock); | ||
220 | |||
221 | list_for_each_entry(hook, &step_hook, node) { | ||
222 | retval = hook->fn(regs, esr); | ||
223 | if (retval == DBG_HOOK_HANDLED) | ||
224 | break; | ||
225 | } | ||
226 | |||
227 | read_unlock(&step_hook_lock); | ||
228 | |||
229 | return retval; | ||
230 | } | ||
231 | |||
190 | static int single_step_handler(unsigned long addr, unsigned int esr, | 232 | static int single_step_handler(unsigned long addr, unsigned int esr, |
191 | struct pt_regs *regs) | 233 | struct pt_regs *regs) |
192 | { | 234 | { |
@@ -214,7 +256,9 @@ static int single_step_handler(unsigned long addr, unsigned int esr, | |||
214 | */ | 256 | */ |
215 | user_rewind_single_step(current); | 257 | user_rewind_single_step(current); |
216 | } else { | 258 | } else { |
217 | /* TODO: route to KGDB */ | 259 | if (call_step_hook(regs, esr) == DBG_HOOK_HANDLED) |
260 | return 0; | ||
261 | |||
218 | pr_warning("Unexpected kernel single-step exception at EL1\n"); | 262 | pr_warning("Unexpected kernel single-step exception at EL1\n"); |
219 | /* | 263 | /* |
220 | * Re-enable stepping since we know that we will be | 264 | * Re-enable stepping since we know that we will be |
@@ -226,11 +270,53 @@ static int single_step_handler(unsigned long addr, unsigned int esr, | |||
226 | return 0; | 270 | return 0; |
227 | } | 271 | } |
228 | 272 | ||
273 | /* | ||
274 | * Breakpoint handler is re-entrant as another breakpoint can | ||
275 | * hit within breakpoint handler, especically in kprobes. | ||
276 | * Use reader/writer locks instead of plain spinlock. | ||
277 | */ | ||
278 | static LIST_HEAD(break_hook); | ||
279 | DEFINE_RWLOCK(break_hook_lock); | ||
280 | |||
281 | void register_break_hook(struct break_hook *hook) | ||
282 | { | ||
283 | write_lock(&break_hook_lock); | ||
284 | list_add(&hook->node, &break_hook); | ||
285 | write_unlock(&break_hook_lock); | ||
286 | } | ||
287 | |||
288 | void unregister_break_hook(struct break_hook *hook) | ||
289 | { | ||
290 | write_lock(&break_hook_lock); | ||
291 | list_del(&hook->node); | ||
292 | write_unlock(&break_hook_lock); | ||
293 | } | ||
294 | |||
295 | static int call_break_hook(struct pt_regs *regs, unsigned int esr) | ||
296 | { | ||
297 | struct break_hook *hook; | ||
298 | int (*fn)(struct pt_regs *regs, unsigned int esr) = NULL; | ||
299 | |||
300 | read_lock(&break_hook_lock); | ||
301 | list_for_each_entry(hook, &break_hook, node) | ||
302 | if ((esr & hook->esr_mask) == hook->esr_val) | ||
303 | fn = hook->fn; | ||
304 | read_unlock(&break_hook_lock); | ||
305 | |||
306 | return fn ? fn(regs, esr) : DBG_HOOK_ERROR; | ||
307 | } | ||
308 | |||
229 | static int brk_handler(unsigned long addr, unsigned int esr, | 309 | static int brk_handler(unsigned long addr, unsigned int esr, |
230 | struct pt_regs *regs) | 310 | struct pt_regs *regs) |
231 | { | 311 | { |
232 | siginfo_t info; | 312 | siginfo_t info; |
233 | 313 | ||
314 | if (call_break_hook(regs, esr) == DBG_HOOK_HANDLED) | ||
315 | return 0; | ||
316 | |||
317 | pr_warn("unexpected brk exception at %lx, esr=0x%x\n", | ||
318 | (long)instruction_pointer(regs), esr); | ||
319 | |||
234 | if (!user_mode(regs)) | 320 | if (!user_mode(regs)) |
235 | return -EFAULT; | 321 | return -EFAULT; |
236 | 322 | ||