Merge tag 'kgdb-5.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux

Pull kgdb updates from Daniel Thompson:
 "The major change here is the work from Douglas Anderson that reworks
  the way kdb stack traces are handled on SMP systems. The effect is to
  allow all CPUs to issue their stack trace which reduced the need for
  architecture specific code to support stack tracing.

  Also included are general of clean ups from Doug and myself:

   - Remove some unused variables or arguments.

   - Tidy up the kdb escape handling code and fix a couple of odd corner
     cases.

   - Better ignore escape characters that do not form part of an escape
     sequence. This mostly benefits vi users since they are most likely
     to press escape as a nervous habit but it won't harm anyone else"

* tag 'kgdb-5.5-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/danielt/linux:
  kdb: Tweak escape handling for vi users
  kdb: Improve handling of characters from different input sources
  kdb: Remove special case logic from kdb_read()
  kdb: Simplify code to fetch characters from console
  kdb: Tidy up code to handle escape sequences
  kdb: Avoid array subscript warnings on non-SMP builds
  kdb: Fix stack crawling on 'running' CPUs that aren't the master
  kdb: Fix "btc <cpu>" crash if the CPU didn't round up
  kdb: Remove unused "argcount" param from kdb_bt1(); make btaprompt bool
  kgdb: Remove unused DCPU_SSTEP definition

1 files changed, 61 insertions, 55 deletions

diff --git a/kernel/debug/kdb/kdb_bt.c b/kernel/debug/kdb/kdb_bt.c
index 7e2379aa0a1e..4af48ac53625 100644
--- a/kernel/debug/kdb/kdb_bt.c
+++ b/kernel/debug/kdb/kdb_bt.c
@@ -22,20 +22,15 @@
 static void kdb_show_stack(struct task_struct *p, void *addr)
 {
 	int old_lvl = console_loglevel;
+
 	console_loglevel = CONSOLE_LOGLEVEL_MOTORMOUTH;
 	kdb_trap_printk++;
-	kdb_set_current_task(p);
-	if (addr) {
-		show_stack((struct task_struct *)p, addr);
-	} else if (kdb_current_regs) {
-#ifdef CONFIG_X86
-		show_stack(p, &kdb_current_regs->sp);
-#else
-		show_stack(p, NULL);
-#endif
-	} else {
-		show_stack(p, NULL);
-	}
+
+	if (!addr && kdb_task_has_cpu(p))
+		kdb_dump_stack_on_cpu(kdb_process_cpu(p));
+	else
+		show_stack(p, addr);
+
 	console_loglevel = old_lvl;
 	kdb_trap_printk--;
 }
@@ -78,12 +73,12 @@ static void kdb_show_stack(struct task_struct *p, void *addr)
  */
 
 static int
-kdb_bt1(struct task_struct *p, unsigned long mask,
-	int argcount, int btaprompt)
+kdb_bt1(struct task_struct *p, unsigned long mask, bool btaprompt)
 {
-	char buffer[2];
-	if (kdb_getarea(buffer[0], (unsigned long)p) ||
-	    kdb_getarea(buffer[0], (unsigned long)(p+1)-1))
+	char ch;
+
+	if (kdb_getarea(ch, (unsigned long)p) ||
+	    kdb_getarea(ch, (unsigned long)(p+1)-1))
 		return KDB_BADADDR;
 	if (!kdb_task_state(p, mask))
 		return 0;
@@ -91,22 +86,47 @@ kdb_bt1(struct task_struct *p, unsigned long mask,
 	kdb_ps1(p);
 	kdb_show_stack(p, NULL);
 	if (btaprompt) {
-		kdb_getstr(buffer, sizeof(buffer),
-			   "Enter <q> to end, <cr> to continue:");
-		if (buffer[0] == 'q') {
-			kdb_printf("\n");
+		kdb_printf("Enter <q> to end, <cr> or <space> to continue:");
+		do {
+			ch = kdb_getchar();
+		} while (!strchr("\r\n q", ch));
+		kdb_printf("\n");
+
+		/* reset the pager */
+		kdb_nextline = 1;
+
+		if (ch == 'q')
 			return 1;
-		}
 	}
 	touch_nmi_watchdog();
 	return 0;
 }
 
+static void
+kdb_bt_cpu(unsigned long cpu)
+{
+	struct task_struct *kdb_tsk;
+
+	if (cpu >= num_possible_cpus() || !cpu_online(cpu)) {
+		kdb_printf("WARNING: no process for cpu %ld\n", cpu);
+		return;
+	}
+
+	/* If a CPU failed to round up we could be here */
+	kdb_tsk = KDB_TSK(cpu);
+	if (!kdb_tsk) {
+		kdb_printf("WARNING: no task for cpu %ld\n", cpu);
+		return;
+	}
+
+	kdb_set_current_task(kdb_tsk);
+	kdb_bt1(kdb_tsk, ~0UL, false);
+}
+
 int
 kdb_bt(int argc, const char **argv)
 {
 	int diag;
-	int argcount = 5;
 	int btaprompt = 1;
 	int nextarg;
 	unsigned long addr;
@@ -125,7 +145,7 @@ kdb_bt(int argc, const char **argv)
 		/* Run the active tasks first */
 		for_each_online_cpu(cpu) {
 			p = kdb_curr_task(cpu);
-			if (kdb_bt1(p, mask, argcount, btaprompt))
+			if (kdb_bt1(p, mask, btaprompt))
 				return 0;
 		}
 		/* Now the inactive tasks */
@@ -134,7 +154,7 @@ kdb_bt(int argc, const char **argv)
 				return 0;
 			if (task_curr(p))
 				continue;
-			if (kdb_bt1(p, mask, argcount, btaprompt))
+			if (kdb_bt1(p, mask, btaprompt))
 				return 0;
 		} kdb_while_each_thread(g, p);
 	} else if (strcmp(argv[0], "btp") == 0) {
@@ -148,7 +168,7 @@ kdb_bt(int argc, const char **argv)
 		p = find_task_by_pid_ns(pid, &init_pid_ns);
 		if (p) {
 			kdb_set_current_task(p);
-			return kdb_bt1(p, ~0UL, argcount, 0);
+			return kdb_bt1(p, ~0UL, false);
 		}
 		kdb_printf("No process with pid == %ld found\n", pid);
 		return 0;
@@ -159,11 +179,10 @@ kdb_bt(int argc, const char **argv)
 		if (diag)
 			return diag;
 		kdb_set_current_task((struct task_struct *)addr);
-		return kdb_bt1((struct task_struct *)addr, ~0UL, argcount, 0);
+		return kdb_bt1((struct task_struct *)addr, ~0UL, false);
 	} else if (strcmp(argv[0], "btc") == 0) {
 		unsigned long cpu = ~0;
 		struct task_struct *save_current_task = kdb_current_task;
-		char buf[80];
 		if (argc > 1)
 			return KDB_ARGCOUNT;
 		if (argc == 1) {
@@ -171,35 +190,22 @@ kdb_bt(int argc, const char **argv)
 			if (diag)
 				return diag;
 		}
-		/* Recursive use of kdb_parse, do not use argv after
-		 * this point */
-		argv = NULL;
 		if (cpu != ~0) {
-			if (cpu >= num_possible_cpus() || !cpu_online(cpu)) {
-				kdb_printf("no process for cpu %ld\n", cpu);
-				return 0;
-			}
-			sprintf(buf, "btt 0x%px\n", KDB_TSK(cpu));
-			kdb_parse(buf);
-			return 0;
-		}
-		kdb_printf("btc: cpu status: ");
-		kdb_parse("cpu\n");
-		for_each_online_cpu(cpu) {
-			void *kdb_tsk = KDB_TSK(cpu);
-
-			/* If a CPU failed to round up we could be here */
-			if (!kdb_tsk) {
-				kdb_printf("WARNING: no task for cpu %ld\n",
-					   cpu);
-				continue;
+			kdb_bt_cpu(cpu);
+		} else {
+			/*
+			 * Recursive use of kdb_parse, do not use argv after
+			 * this point.
+			 */
+			argv = NULL;
+			kdb_printf("btc: cpu status: ");
+			kdb_parse("cpu\n");
+			for_each_online_cpu(cpu) {
+				kdb_bt_cpu(cpu);
+				touch_nmi_watchdog();
 			}
-
-			sprintf(buf, "btt 0x%px\n", kdb_tsk);
-			kdb_parse(buf);
-			touch_nmi_watchdog();
+			kdb_set_current_task(save_current_task);
 		}
-		kdb_set_current_task(save_current_task);
 		return 0;
 	} else {
 		if (argc) {
@@ -211,7 +217,7 @@ kdb_bt(int argc, const char **argv)
 			kdb_show_stack(kdb_current_task, (void *)addr);
 			return 0;
 		} else {
-			return kdb_bt1(kdb_current_task, ~0UL, argcount, 0);
+			return kdb_bt1(kdb_current_task, ~0UL, false);
 		}
 	}