Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
[linux-2.6.git] / kernel / kgdb.c
index eaa21fc..761fdd2 100644 (file)
@@ -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];
@@ -488,7 +489,7 @@ static int write_mem_msg(int binary)
                if (err)
                        return err;
                if (CACHE_FLUSH_IS_SAFE)
-                       flush_icache_range(addr, addr + length + 1);
+                       flush_icache_range(addr, addr + length);
                return 0;
        }
 
@@ -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();
@@ -590,6 +599,7 @@ static void kgdb_wait(struct pt_regs *regs)
 
        /* Signal the primary CPU that we are done: */
        atomic_set(&cpu_in_kgdb[cpu], 0);
+       touch_softlockup_watchdog_sync();
        clocksource_touch_watchdog();
        local_irq_restore(flags);
 }
@@ -618,7 +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++) {
@@ -628,13 +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)
@@ -681,7 +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++) {
@@ -690,13 +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)
@@ -869,7 +886,7 @@ static void gdb_cmd_getregs(struct kgdb_state *ks)
 
        /*
         * All threads that don't have debuggerinfo should be
-        * in __schedule() sleeping, since all other CPUs
+        * in schedule() sleeping, since all other CPUs
         * are in kgdb_wait, and thus have debuggerinfo.
         */
        if (local_debuggerinfo) {
@@ -1203,8 +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 */
@@ -1394,6 +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;
 
@@ -1424,14 +1444,16 @@ 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_sync();
                clocksource_touch_watchdog();
                local_irq_restore(flags);
 
@@ -1462,7 +1484,7 @@ acquirelock:
         * Get the passive CPU lock which will hold all the non-primary
         * CPU in a spin state while the debugger is active
         */
-       if (!kgdb_single_step || !kgdb_contthread) {
+       if (!kgdb_single_step) {
                for (i = 0; i < NR_CPUS; i++)
                        atomic_set(&passive_cpu_wait[i], 1);
        }
@@ -1475,7 +1497,7 @@ acquirelock:
 
 #ifdef CONFIG_SMP
        /* Signal the other CPUs to enter kgdb_wait() */
-       if ((!kgdb_single_step || !kgdb_contthread) && kgdb_do_roundup)
+       if ((!kgdb_single_step) && kgdb_do_roundup)
                kgdb_roundup_cpus(flags);
 #endif
 
@@ -1494,7 +1516,7 @@ acquirelock:
        kgdb_post_primary_code(ks->linux_regs, ks->ex_vector, ks->err_code);
        kgdb_deactivate_sw_breakpoints();
        kgdb_single_step = 0;
-       kgdb_contthread = NULL;
+       kgdb_contthread = current;
        exception_level = 0;
 
        /* Talk to debugger with gdbserial protocol */
@@ -1508,7 +1530,7 @@ acquirelock:
        kgdb_info[ks->cpu].task = NULL;
        atomic_set(&cpu_in_kgdb[ks->cpu], 0);
 
-       if (!kgdb_single_step || !kgdb_contthread) {
+       if (!kgdb_single_step) {
                for (i = NR_CPUS-1; i >= 0; i--)
                        atomic_set(&passive_cpu_wait[i], 0);
                /*
@@ -1522,8 +1544,16 @@ 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_sync();
        clocksource_touch_watchdog();
        local_irq_restore(flags);
 
@@ -1580,8 +1610,8 @@ static void sysrq_handle_gdb(int key, struct tty_struct *tty)
 
 static struct sysrq_key_op sysrq_gdb_op = {
        .handler        = sysrq_handle_gdb,
-       .help_msg       = "Gdb",
-       .action_msg     = "GDB",
+       .help_msg       = "debug(G)",
+       .action_msg     = "DEBUG",
 };
 #endif