diff options
Diffstat (limited to 'kernel/kgdb.c')
| -rw-r--r-- | kernel/kgdb.c | 59 |
1 files changed, 43 insertions, 16 deletions
diff --git a/kernel/kgdb.c b/kernel/kgdb.c index 7d7014634022..c7ade62e4ef0 100644 --- a/kernel/kgdb.c +++ b/kernel/kgdb.c @@ -129,6 +129,7 @@ struct task_struct *kgdb_usethread; struct task_struct *kgdb_contthread; int kgdb_single_step; +pid_t kgdb_sstep_pid; /* Our I/O buffers. */ static char remcom_in_buffer[BUFMAX]; @@ -541,12 +542,17 @@ static struct task_struct *getthread(struct pt_regs *regs, int tid) */ if (tid == 0 || tid == -1) tid = -atomic_read(&kgdb_active) - 2; - if (tid < 0) { + if (tid < -1 && tid > -NR_CPUS - 2) { if (kgdb_info[-tid - 2].task) return kgdb_info[-tid - 2].task; else return idle_task(-tid - 2); } + if (tid <= 0) { + printk(KERN_ERR "KGDB: Internal thread select error\n"); + dump_stack(); + return NULL; + } /* * find_task_by_pid_ns() does not take the tasklist lock anymore @@ -577,6 +583,9 @@ static void kgdb_wait(struct pt_regs *regs) smp_wmb(); atomic_set(&cpu_in_kgdb[cpu], 1); + /* Disable any cpu specific hw breakpoints */ + kgdb_disable_hw_debug(regs); + /* Wait till primary CPU is done with debugging */ while (atomic_read(&passive_cpu_wait[cpu])) cpu_relax(); @@ -619,7 +628,8 @@ static void kgdb_flush_swbreak_addr(unsigned long addr) static int kgdb_activate_sw_breakpoints(void) { unsigned long addr; - int error = 0; + int error; + int ret = 0; int i; for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { @@ -629,13 +639,16 @@ static int kgdb_activate_sw_breakpoints(void) addr = kgdb_break[i].bpt_addr; error = kgdb_arch_set_breakpoint(addr, kgdb_break[i].saved_instr); - if (error) - return error; + if (error) { + ret = error; + printk(KERN_INFO "KGDB: BP install failed: %lx", addr); + continue; + } kgdb_flush_swbreak_addr(addr); kgdb_break[i].state = BP_ACTIVE; } - return 0; + return ret; } static int kgdb_set_sw_break(unsigned long addr) @@ -682,7 +695,8 @@ static int kgdb_set_sw_break(unsigned long addr) static int kgdb_deactivate_sw_breakpoints(void) { unsigned long addr; - int error = 0; + int error; + int ret = 0; int i; for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) { @@ -691,13 +705,15 @@ static int kgdb_deactivate_sw_breakpoints(void) addr = kgdb_break[i].bpt_addr; error = kgdb_arch_remove_breakpoint(addr, kgdb_break[i].saved_instr); - if (error) - return error; + if (error) { + printk(KERN_INFO "KGDB: BP remove failed: %lx\n", addr); + ret = error; + } kgdb_flush_swbreak_addr(addr); kgdb_break[i].state = BP_SET; } - return 0; + return ret; } static int kgdb_remove_sw_break(unsigned long addr) @@ -1204,8 +1220,10 @@ static int gdb_cmd_exception_pass(struct kgdb_state *ks) return 1; } else { - error_packet(remcom_out_buffer, -EINVAL); - return 0; + kgdb_msg_write("KGDB only knows signal 9 (pass)" + " and 15 (pass and disconnect)\n" + "Executing a continue without signal passing\n", 0); + remcom_in_buffer[0] = 'c'; } /* Indicate fall through */ @@ -1395,6 +1413,7 @@ kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs) struct kgdb_state kgdb_var; struct kgdb_state *ks = &kgdb_var; unsigned long flags; + int sstep_tries = 100; int error = 0; int i, cpu; @@ -1425,13 +1444,14 @@ acquirelock: cpu_relax(); /* - * Do not start the debugger connection on this CPU if the last - * instance of the exception handler wanted to come into the - * debugger on a different CPU via a single step + * For single stepping, try to only enter on the processor + * that was single stepping. To gaurd against a deadlock, the + * kernel will only try for the value of sstep_tries before + * giving up and continuing on. */ if (atomic_read(&kgdb_cpu_doing_single_step) != -1 && - atomic_read(&kgdb_cpu_doing_single_step) != cpu) { - + (kgdb_info[cpu].task && + kgdb_info[cpu].task->pid != kgdb_sstep_pid) && --sstep_tries) { atomic_set(&kgdb_active, -1); touch_softlockup_watchdog(); clocksource_touch_watchdog(); @@ -1524,6 +1544,13 @@ acquirelock: } kgdb_restore: + if (atomic_read(&kgdb_cpu_doing_single_step) != -1) { + int sstep_cpu = atomic_read(&kgdb_cpu_doing_single_step); + if (kgdb_info[sstep_cpu].task) + kgdb_sstep_pid = kgdb_info[sstep_cpu].task->pid; + else + kgdb_sstep_pid = 0; + } /* Free kgdb_active */ atomic_set(&kgdb_active, -1); touch_softlockup_watchdog(); |