Merge tag 'for_linus-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb

Pull KGDB/KDB fixes and cleanups from Jason Wessel:
 "Cleanups
   - Clean up compile warnings in kgdboc.c and x86/kernel/kgdb.c
   - Add module event hooks for simplified debugging with gdb
 Fixes
   - Fix kdb to stop paging with 'q' on bta and dmesg
   - Fix for data that scrolls off the vga console due to line wrapping
     when using the kdb pager
 New
   - The debug core registers for kernel module events which allows a
     kernel aware gdb to automatically load symbols and break on entry
     to a kernel module
   - Allow kgdboc=kdb to setup kdb on the vga console"

* tag 'for_linus-3.7' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb:
  tty/console: fix warnings in drivers/tty/serial/kgdboc.c
  kdb,vt_console: Fix missed data due to pager overruns
  kdb: Fix dmesg/bta scroll to quit with 'q'
  kgdboc: Accept either kbd or kdb to activate the vga + keyboard kdb shell
  kgdb,x86: fix warning about unused variable
  mips,kgdb: fix recursive page fault with CONFIG_KPROBES
  kgdb: Add module event hooks

9 files changed, 84 insertions, 8 deletions

diff --git a/arch/mips/kernel/kgdb.c b/arch/mips/kernel/kgdb.c
index f4546e97c60d..23817a6e32b6 100644
--- a/arch/mips/kernel/kgdb.c
+++ b/arch/mips/kernel/kgdb.c
@@ -283,6 +283,15 @@ static int kgdb_mips_notify(struct notifier_block *self, unsigned long cmd,
         struct pt_regs *regs = args->regs;
         int trap = (regs->cp0_cause & 0x7c) >> 2;
 
+#ifdef CONFIG_KPROBES
+        /*
+         * Return immediately if the kprobes fault notifier has set
+         * DIE_PAGE_FAULT.
+         */
+        if (cmd == DIE_PAGE_FAULT)
+                return NOTIFY_DONE;
+#endif /* CONFIG_KPROBES */
+
         /* Userspace events, ignore. */
         if (user_mode(regs))
                 return NOTIFY_DONE;
diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c
index 3f61904365cf..836f8322960e 100644
--- a/arch/x86/kernel/kgdb.c
+++ b/arch/x86/kernel/kgdb.c
@@ -746,7 +746,9 @@ void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
 int kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
 {
         int err;
+#ifdef CONFIG_DEBUG_RODATA
         char opc[BREAK_INSTR_SIZE];
+#endif /* CONFIG_DEBUG_RODATA */
 
         bpt->type = BP_BREAKPOINT;
         err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr,
diff --git a/drivers/tty/serial/kgdboc.c b/drivers/tty/serial/kgdboc.c
index c0b334327d93..10020547c60b 100644
--- a/drivers/tty/serial/kgdboc.c
+++ b/drivers/tty/serial/kgdboc.c
@@ -97,7 +97,8 @@ static void kgdboc_restore_input(void)
 
 static int kgdboc_register_kbd(char **cptr)
 {
-        if (strncmp(*cptr, "kbd", 3) == 0) {
+        if (strncmp(*cptr, "kbd", 3) == 0 ||
+                strncmp(*cptr, "kdb", 3) == 0) {
                 if (kdb_poll_idx < KDB_POLL_FUNC_MAX) {
                         kdb_poll_funcs[kdb_poll_idx] = kdb_get_kbd_char;
                         kdb_poll_idx++;
diff --git a/drivers/tty/vt/vt.c b/drivers/tty/vt/vt.c
index 999ca63afdef..f87d7e8964bf 100644
--- a/drivers/tty/vt/vt.c
+++ b/drivers/tty/vt/vt.c
@@ -3442,6 +3442,19 @@ int con_debug_enter(struct vc_data *vc)
                         kdb_set(2, setargs);
                 }
         }
+        if (vc->vc_cols < 999) {
+                int colcount;
+                char cols[4];
+                const char *setargs[3] = {
+                        "set",
+                        "COLUMNS",
+                        cols,
+                };
+                if (kdbgetintenv(setargs[0], &colcount)) {
+                        snprintf(cols, 4, "%i", vc->vc_cols);
+                        kdb_set(2, setargs);
+                }
+        }
 #endif /* CONFIG_KGDB_KDB */
         return ret;
 }
diff --git a/include/linux/console.h b/include/linux/console.h
index 7201ce4280ca..dedb082fe50f 100644
--- a/include/linux/console.h
+++ b/include/linux/console.h
@@ -83,8 +83,14 @@ void give_up_console(const struct consw *sw);
 int con_debug_enter(struct vc_data *vc);
 int con_debug_leave(void);
 #else
-#define con_debug_enter(vc) (0)
-#define con_debug_leave() (0)
+static inline int con_debug_enter(struct vc_data *vc)
+{
+        return 0;
+}
+static inline int con_debug_leave(void)
+{
+        return 0;
+}
 #endif
 
 /* scroll */
diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c
index 17e073c309e6..9a61738cefc8 100644
--- a/kernel/debug/debug_core.c
+++ b/kernel/debug/debug_core.c
@@ -696,6 +696,22 @@ out:
         return ret;
 }
 
+/*
+ * GDB places a breakpoint at this function to know dynamically
+ * loaded objects. It's not defined static so that only one instance with this
+ * name exists in the kernel.
+ */
+
+static int module_event(struct notifier_block *self, unsigned long val,
+        void *data)
+{
+        return 0;
+}
+
+static struct notifier_block dbg_module_load_nb = {
+        .notifier_call  = module_event,
+};
+
 int kgdb_nmicallback(int cpu, void *regs)
 {
 #ifdef CONFIG_SMP
@@ -824,6 +840,7 @@ static void kgdb_register_callbacks(void)
                 kgdb_arch_init();
                 if (!dbg_is_early)
                         kgdb_arch_late();
+                register_module_notifier(&dbg_module_load_nb);
                 register_reboot_notifier(&dbg_reboot_notifier);
                 atomic_notifier_chain_register(&panic_notifier_list,
                                                &kgdb_panic_event_nb);
@@ -847,6 +864,7 @@ static void kgdb_unregister_callbacks(void)
         if (kgdb_io_module_registered) {
                 kgdb_io_module_registered = 0;
                 unregister_reboot_notifier(&dbg_reboot_notifier);
+                unregister_module_notifier(&dbg_module_load_nb);
                 atomic_notifier_chain_unregister(&panic_notifier_list,
                                                &kgdb_panic_event_nb);
                 kgdb_arch_exit();
diff --git a/kernel/debug/kdb/kdb_bt.c b/kernel/debug/kdb/kdb_bt.c
index 07c9bbb94a0b..b03e0e814e43 100644
--- a/kernel/debug/kdb/kdb_bt.c
+++ b/kernel/debug/kdb/kdb_bt.c
@@ -129,6 +129,8 @@ kdb_bt(int argc, const char **argv)
                 }
                 /* Now the inactive tasks */
                 kdb_do_each_thread(g, p) {
+                        if (KDB_FLAG(CMD_INTERRUPT))
+                                return 0;
                         if (task_curr(p))
                                 continue;
                         if (kdb_bt1(p, mask, argcount, btaprompt))
diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index 0a69d2adc4f3..14ff4849262c 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -552,6 +552,7 @@ int vkdb_printf(const char *fmt, va_list ap)
 {
         int diag;
         int linecount;
+        int colcount;
         int logging, saved_loglevel = 0;
         int saved_trap_printk;
         int got_printf_lock = 0;
@@ -584,6 +585,10 @@ int vkdb_printf(const char *fmt, va_list ap)
         if (diag || linecount <= 1)
                 linecount = 24;
 
+        diag = kdbgetintenv("COLUMNS", &colcount);
+        if (diag || colcount <= 1)
+                colcount = 80;
+
         diag = kdbgetintenv("LOGGING", &logging);
         if (diag)
                 logging = 0;
@@ -690,7 +695,7 @@ kdb_printit:
                 gdbstub_msg_write(kdb_buffer, retlen);
         } else {
                 if (dbg_io_ops && !dbg_io_ops->is_console) {
-                        len = strlen(kdb_buffer);
+                        len = retlen;
                         cp = kdb_buffer;
                         while (len--) {
                                 dbg_io_ops->write_char(*cp);
@@ -709,11 +714,29 @@ kdb_printit:
                 printk(KERN_INFO "%s", kdb_buffer);
         }
 
-        if (KDB_STATE(PAGER) && strchr(kdb_buffer, '\n'))
-                kdb_nextline++;
+        if (KDB_STATE(PAGER)) {
+                /*
+                 * Check printed string to decide how to bump the
+                 * kdb_nextline to control when the more prompt should
+                 * show up.
+                 */
+                int got = 0;
+                len = retlen;
+                while (len--) {
+                        if (kdb_buffer[len] == '\n') {
+                                kdb_nextline++;
+                                got = 0;
+                        } else if (kdb_buffer[len] == '\r') {
+                                got = 0;
+                        } else {
+                                got++;
+                        }
+                }
+                kdb_nextline += got / (colcount + 1);
+        }
 
         /* check for having reached the LINES number of printed lines */
-        if (kdb_nextline == linecount) {
+        if (kdb_nextline >= linecount) {
                 char buf1[16] = "";
 
                 /* Watch out for recursion here.  Any routine that calls
@@ -765,7 +788,7 @@ kdb_printit:
                         kdb_grepping_flag = 0;
                         kdb_printf("\n");
                 } else if (buf1[0] == ' ') {
-                        kdb_printf("\n");
+                        kdb_printf("\r");
                         suspend_grep = 1; /* for this recursion */
                 } else if (buf1[0] == '\n') {
                         kdb_nextline = linecount - 1;
diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
index 1261dc7eaeb9..4d5f8d5612f3 100644
--- a/kernel/debug/kdb/kdb_main.c
+++ b/kernel/debug/kdb/kdb_main.c
@@ -2101,6 +2101,8 @@ static int kdb_dmesg(int argc, const char **argv)
                 }
                 if (!lines--)
                         break;
+                if (KDB_FLAG(CMD_INTERRUPT))
+                        return 0;
 
                 kdb_printf("%.*s\n", (int)len - 1, buf);
         }