Merge tag 'tty-3.6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull TTY changes from Greg Kroah-Hartman:
 "As we skipped the merge window for 3.6-rc1 for the tty tree,
  everything is now settled down and working properly, so we are ready
  for 3.7-rc1.  Here's the patchset, it's big, but the large changes are
  removing a firmware file and adding a staging tty driver (it depended
  on the tty core changes, so it's going through this tree instead of
  the staging tree.)

  All of these patches have been in the linux-next tree for a while.

  Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>"

Fix up more-or-less trivial conflicts in
 - drivers/char/pcmcia/synclink_cs.c:
    tty NULL dereference fix vs tty_port_cts_enabled() helper function
 - drivers/staging/{Kconfig,Makefile}:
    add-add conflict (dgrp driver added close to other staging drivers)
 - drivers/staging/ipack/devices/ipoctal.c:
    "split ipoctal_channel from iopctal" vs "TTY: use tty_port_register_device"

* tag 'tty-3.6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (235 commits)
  tty/serial: Add kgdb_nmi driver
  tty/serial/amba-pl011: Quiesce interrupts in poll_get_char
  tty/serial/amba-pl011: Implement poll_init callback
  tty/serial/core: Introduce poll_init callback
  kdb: Turn KGDB_KDB=n stubs into static inlines
  kdb: Implement disable_nmi command
  kernel/debug: Mask KGDB NMI upon entry
  serial: pl011: handle corruption at high clock speeds
  serial: sccnxp: Make 'default' choice in switch last
  serial: sccnxp: Remove mask termios caps for SW flow control
  serial: sccnxp: Report actual baudrate back to core
  serial: samsung: Add poll_get_char & poll_put_char
  Powerpc 8xx CPM_UART setting MAXIDL register proportionaly to baud rate
  Powerpc 8xx CPM_UART maxidl should not depend on fifo size
  Powerpc 8xx CPM_UART too many interrupts
  Powerpc 8xx CPM_UART desynchronisation
  serial: set correct baud_base for EXSYS EX-41092 Dual 16950
  serial: omap: fix the reciever line error case
  8250: blacklist Winbond CIR port
  8250_pnp: do pnp probe before legacy probe
  ...

2 files changed, 42 insertions, 3 deletions

diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c
index 0557f24c6bca..17e073c309e6 100644
--- a/kernel/debug/debug_core.c
+++ b/kernel/debug/debug_core.c
@@ -672,6 +672,10 @@ kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs)
 {
 	struct kgdb_state kgdb_var;
 	struct kgdb_state *ks = &kgdb_var;
+	int ret = 0;
+
+	if (arch_kgdb_ops.enable_nmi)
+		arch_kgdb_ops.enable_nmi(0);
 
 	ks->cpu			= raw_smp_processor_id();
 	ks->ex_vector		= evector;
@@ -681,11 +685,15 @@ kgdb_handle_exception(int evector, int signo, int ecode, struct pt_regs *regs)
 	ks->linux_regs		= regs;
 
 	if (kgdb_reenter_check(ks))
-		return 0; /* Ouch, double exception ! */
+		goto out; /* Ouch, double exception ! */
 	if (kgdb_info[ks->cpu].enter_kgdb != 0)
-		return 0;
+		goto out;
 
-	return kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER);
+	ret = kgdb_cpu_enter(ks, regs, DCPU_WANT_MASTER);
+out:
+	if (arch_kgdb_ops.enable_nmi)
+		arch_kgdb_ops.enable_nmi(1);
+	return ret;
 }
 
 int kgdb_nmicallback(int cpu, void *regs)
diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
index 31df1706b9a9..1261dc7eaeb9 100644
--- a/kernel/debug/kdb/kdb_main.c
+++ b/kernel/debug/kdb/kdb_main.c
@@ -21,6 +21,7 @@
 #include <linux/smp.h>
 #include <linux/utsname.h>
 #include <linux/vmalloc.h>
+#include <linux/atomic.h>
 #include <linux/module.h>
 #include <linux/mm.h>
 #include <linux/init.h>
@@ -2107,6 +2108,32 @@ static int kdb_dmesg(int argc, const char **argv)
 	return 0;
 }
 #endif /* CONFIG_PRINTK */
+
+/* Make sure we balance enable/disable calls, must disable first. */
+static atomic_t kdb_nmi_disabled;
+
+static int kdb_disable_nmi(int argc, const char *argv[])
+{
+	if (atomic_read(&kdb_nmi_disabled))
+		return 0;
+	atomic_set(&kdb_nmi_disabled, 1);
+	arch_kgdb_ops.enable_nmi(0);
+	return 0;
+}
+
+static int kdb_param_enable_nmi(const char *val, const struct kernel_param *kp)
+{
+	if (!atomic_add_unless(&kdb_nmi_disabled, -1, 0))
+		return -EINVAL;
+	arch_kgdb_ops.enable_nmi(1);
+	return 0;
+}
+
+static const struct kernel_param_ops kdb_param_ops_enable_nmi = {
+	.set = kdb_param_enable_nmi,
+};
+module_param_cb(enable_nmi, &kdb_param_ops_enable_nmi, NULL, 0600);
+
 /*
  * kdb_cpu - This function implements the 'cpu' command.
  *	cpu	[<cpunum>]
@@ -2851,6 +2878,10 @@ static void __init kdb_inittab(void)
 	kdb_register_repeat("dmesg", kdb_dmesg, "[lines]",
 	  "Display syslog buffer", 0, KDB_REPEAT_NONE);
 #endif
+	if (arch_kgdb_ops.enable_nmi) {
+		kdb_register_repeat("disable_nmi", kdb_disable_nmi, "",
+		  "Disable NMI entry to KDB", 0, KDB_REPEAT_NONE);
+	}
 	kdb_register_repeat("defcmd", kdb_defcmd, "name \"usage\" \"help\"",
 	  "Define a set of commands, down to endefcmd", 0, KDB_REPEAT_NONE);
 	kdb_register_repeat("kill", kdb_kill, "<-signal> <pid>",