Merge branch 'kdb-merge' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb

* 'kdb-merge' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb: (25 commits)
  kdb,debug_core: Allow the debug core to receive a panic notification
  MAINTAINERS: update kgdb, kdb, and debug_core info
  debug_core,kdb: Allow the debug core to process a recursive debug entry
  printk,kdb: capture printk() when in kdb shell
  kgdboc,kdb: Allow kdb to work on a non open console port
  kgdb: Add the ability to schedule a breakpoint via a tasklet
  mips,kgdb: kdb low level trap catch and stack trace
  powerpc,kgdb: Introduce low level trap catching
  x86,kgdb: Add low level debug hook
  kgdb: remove post_primary_code references
  kgdb,docs: Update the kgdb docs to include kdb
  kgdboc,keyboard: Keyboard driver for kdb with kgdb
  kgdb: gdb "monitor" -> kdb passthrough
  sparc,sunzilog: Add console polling support for sunzilog serial driver
  sh,sh-sci: Use NO_POLL_CHAR in the SCIF polled console code
  kgdb,8250,pl011: Return immediately from console poll
  kgdb: core changes to support kdb
  kdb: core for kgdb back end (2 of 2)
  kdb: core for kgdb back end (1 of 2)
  kgdb,blackfin: Add in kgdb_arch_set_pc for blackfin
  ...

15 files changed, 127 insertions, 36 deletions

diff --git a/arch/arm/include/asm/kmap_types.h b/arch/arm/include/asm/kmap_types.h
index c4b2ea3fbe42..e51b1e81df05 100644
--- a/arch/arm/include/asm/kmap_types.h
+++ b/arch/arm/include/asm/kmap_types.h
@@ -20,6 +20,7 @@ enum km_type {
 	KM_SOFTIRQ1,
 	KM_L1_CACHE,
 	KM_L2_CACHE,
+	KM_KDB,
 	KM_TYPE_NR
 };
 
diff --git a/arch/arm/kernel/kgdb.c b/arch/arm/kernel/kgdb.c
index a5b846b9895d..c868a8864117 100644
--- a/arch/arm/kernel/kgdb.c
+++ b/arch/arm/kernel/kgdb.c
@@ -98,6 +98,11 @@ sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *task)
 	gdb_regs[_CPSR]		= thread_regs->ARM_cpsr;
 }
 
+void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
+{
+	regs->ARM_pc = pc;
+}
+
 static int compiled_break;
 
 int kgdb_arch_handle_exception(int exception_vector, int signo,
diff --git a/arch/blackfin/kernel/kgdb.c b/arch/blackfin/kernel/kgdb.c
index 2c501ceb1e55..7367aea4ae59 100644
--- a/arch/blackfin/kernel/kgdb.c
+++ b/arch/blackfin/kernel/kgdb.c
@@ -439,6 +439,11 @@ int kgdb_validate_break_address(unsigned long addr)
 	return -EFAULT;
 }
 
+void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
+{
+	regs->retx = ip;
+}
+
 int kgdb_arch_init(void)
 {
 	kgdb_single_step = 0;
diff --git a/arch/mips/include/asm/kgdb.h b/arch/mips/include/asm/kgdb.h
index 48223b09396c..19002d605ac4 100644
--- a/arch/mips/include/asm/kgdb.h
+++ b/arch/mips/include/asm/kgdb.h
@@ -38,6 +38,8 @@ extern int kgdb_early_setup;
 extern void *saved_vectors[32];
 extern void handle_exception(struct pt_regs *regs);
 extern void breakinst(void);
+extern int kgdb_ll_trap(int cmd, const char *str,
+			struct pt_regs *regs, long err, int trap, int sig);
 
 #endif				/* __KERNEL__ */
 
diff --git a/arch/mips/kernel/kgdb.c b/arch/mips/kernel/kgdb.c
index 50c9bb880667..9b78ff6e9b84 100644
--- a/arch/mips/kernel/kgdb.c
+++ b/arch/mips/kernel/kgdb.c
@@ -180,6 +180,11 @@ void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
 	*(ptr++) = regs->cp0_epc;
 }
 
+void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
+{
+	regs->cp0_epc = pc;
+}
+
 /*
  * Calls linux_debug_hook before the kernel dies. If KGDB is enabled,
  * then try to fall into the debugger
@@ -198,7 +203,7 @@ static int kgdb_mips_notify(struct notifier_block *self, unsigned long cmd,
 	if (atomic_read(&kgdb_active) != -1)
 		kgdb_nmicallback(smp_processor_id(), regs);
 
-	if (kgdb_handle_exception(trap, compute_signal(trap), 0, regs))
+	if (kgdb_handle_exception(trap, compute_signal(trap), cmd, regs))
 		return NOTIFY_DONE;
 
 	if (atomic_read(&kgdb_setting_breakpoint))
@@ -212,6 +217,26 @@ static int kgdb_mips_notify(struct notifier_block *self, unsigned long cmd,
 	return NOTIFY_STOP;
 }
 
+#ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
+int kgdb_ll_trap(int cmd, const char *str,
+		 struct pt_regs *regs, long err, int trap, int sig)
+{
+	struct die_args args = {
+		.regs	= regs,
+		.str	= str,
+		.err	= err,
+		.trapnr	= trap,
+		.signr	= sig,
+
+	};
+
+	if (!kgdb_io_module_registered)
+		return NOTIFY_DONE;
+
+	return kgdb_mips_notify(NULL, cmd, &args);
+}
+#endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */
+
 static struct notifier_block kgdb_notifier = {
 	.notifier_call = kgdb_mips_notify,
 };
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index d612c6dcb746..950bde8813fc 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -26,6 +26,7 @@
 #include <linux/kgdb.h>
 #include <linux/kdebug.h>
 #include <linux/notifier.h>
+#include <linux/kdb.h>
 
 #include <asm/bootinfo.h>
 #include <asm/branch.h>
@@ -185,6 +186,11 @@ void show_stack(struct task_struct *task, unsigned long *sp)
 			regs.regs[29] = task->thread.reg29;
 			regs.regs[31] = 0;
 			regs.cp0_epc = task->thread.reg31;
+#ifdef CONFIG_KGDB_KDB
+		} else if (atomic_read(&kgdb_active) != -1 &&
+			   kdb_current_regs) {
+			memcpy(&regs, kdb_current_regs, sizeof(regs));
+#endif /* CONFIG_KGDB_KDB */
 		} else {
 			prepare_frametrace(&regs);
 		}
@@ -360,6 +366,8 @@ void __noreturn die(const char * str, struct pt_regs * regs)
 	unsigned long dvpret = dvpe();
 #endif /* CONFIG_MIPS_MT_SMTC */
 
+	notify_die(DIE_OOPS, str, (struct pt_regs *)regs, SIGSEGV, 0, 0);
+
 	console_verbose();
 	spin_lock_irq(&die_lock);
 	bust_spinlocks(1);
@@ -704,6 +712,11 @@ static void do_trap_or_bp(struct pt_regs *regs, unsigned int code,
 	siginfo_t info;
 	char b[40];
 
+#ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
+	if (kgdb_ll_trap(DIE_TRAP, str, regs, code, 0, 0) == NOTIFY_STOP)
+		return;
+#endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */
+
 	if (notify_die(DIE_TRAP, str, regs, code, 0, 0) == NOTIFY_STOP)
 		return;
 
diff --git a/arch/powerpc/include/asm/kmap_types.h b/arch/powerpc/include/asm/kmap_types.h
index 916369575c97..bca8fdcd2542 100644
--- a/arch/powerpc/include/asm/kmap_types.h
+++ b/arch/powerpc/include/asm/kmap_types.h
@@ -26,6 +26,7 @@ enum km_type {
 	KM_SOFTIRQ1,
 	KM_PPC_SYNC_PAGE,
 	KM_PPC_SYNC_ICACHE,
+	KM_KDB,
 	KM_TYPE_NR
 };
 
diff --git a/arch/powerpc/kernel/kgdb.c b/arch/powerpc/kernel/kgdb.c
index 41bada0298c8..82a7b228c81a 100644
--- a/arch/powerpc/kernel/kgdb.c
+++ b/arch/powerpc/kernel/kgdb.c
@@ -20,6 +20,7 @@
 #include <linux/smp.h>
 #include <linux/signal.h>
 #include <linux/ptrace.h>
+#include <linux/kdebug.h>
 #include <asm/current.h>
 #include <asm/processor.h>
 #include <asm/machdep.h>
@@ -115,7 +116,8 @@ void kgdb_roundup_cpus(unsigned long flags)
 /* KGDB functions to use existing PowerPC64 hooks. */
 static int kgdb_debugger(struct pt_regs *regs)
 {
-	return kgdb_handle_exception(0, computeSignal(TRAP(regs)), 0, regs);
+	return !kgdb_handle_exception(1, computeSignal(TRAP(regs)),
+				      DIE_OOPS, regs);
 }
 
 static int kgdb_handle_breakpoint(struct pt_regs *regs)
@@ -123,7 +125,7 @@ static int kgdb_handle_breakpoint(struct pt_regs *regs)
 	if (user_mode(regs))
 		return 0;
 
-	if (kgdb_handle_exception(0, SIGTRAP, 0, regs) != 0)
+	if (kgdb_handle_exception(1, SIGTRAP, 0, regs) != 0)
 		return 0;
 
 	if (*(u32 *) (regs->nip) == *(u32 *) (&arch_kgdb_ops.gdb_bpt_instr))
@@ -309,6 +311,11 @@ void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
 	       (unsigned long)(((void *)gdb_regs) + NUMREGBYTES));
 }
 
+void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
+{
+	regs->nip = pc;
+}
+
 /*
  * This function does PowerPC specific procesing for interfacing to gdb.
  */
diff --git a/arch/powerpc/kernel/traps.c b/arch/powerpc/kernel/traps.c
index 29d128eb6c43..b6859aade9c2 100644
--- a/arch/powerpc/kernel/traps.c
+++ b/arch/powerpc/kernel/traps.c
@@ -815,12 +815,15 @@ void __kprobes program_check_exception(struct pt_regs *regs)
 		return;
 	}
 	if (reason & REASON_TRAP) {
+		/* Debugger is first in line to stop recursive faults in
+		 * rcu_lock, notify_die, or atomic_notifier_call_chain */
+		if (debugger_bpt(regs))
+			return;
+
 		/* trap exception */
 		if (notify_die(DIE_BPT, "breakpoint", regs, 5, 5, SIGTRAP)
 				== NOTIFY_STOP)
 			return;
-		if (debugger_bpt(regs))
-			return;
 
 		if (!(regs->msr & MSR_PR) &&  /* not user-mode */
 		    report_bug(regs->nip, regs) == BUG_TRAP_TYPE_WARN) {
diff --git a/arch/sh/kernel/kgdb.c b/arch/sh/kernel/kgdb.c
index 70c69659b846..efb6d398dec3 100644
--- a/arch/sh/kernel/kgdb.c
+++ b/arch/sh/kernel/kgdb.c
@@ -237,6 +237,18 @@ int kgdb_arch_handle_exception(int e_vector, int signo, int err_code,
 	return -1;
 }
 
+unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs)
+{
+	if (exception == 60)
+		return instruction_pointer(regs) - 2;
+	return instruction_pointer(regs);
+}
+
+void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
+{
+	regs->pc = ip;
+}
+
 /*
  * The primary entry points for the kgdb debug trap table entries.
  */
@@ -247,7 +259,7 @@ BUILD_TRAP_HANDLER(singlestep)
 
 	local_irq_save(flags);
 	regs->pc -= instruction_size(__raw_readw(regs->pc - 4));
-	kgdb_handle_exception(vec >> 2, SIGTRAP, 0, regs);
+	kgdb_handle_exception(0, SIGTRAP, 0, regs);
 	local_irq_restore(flags);
 }
 
diff --git a/arch/sparc/kernel/kgdb_32.c b/arch/sparc/kernel/kgdb_32.c
index 04df4edc0073..539243b236fa 100644
--- a/arch/sparc/kernel/kgdb_32.c
+++ b/arch/sparc/kernel/kgdb_32.c
@@ -158,6 +158,12 @@ void kgdb_arch_exit(void)
 {
 }
 
+void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
+{
+	regs->pc = ip;
+	regs->npc = regs->pc + 4;
+}
+
 struct kgdb_arch arch_kgdb_ops = {
 	/* Breakpoint instruction: ta 0x7d */
 	.gdb_bpt_instr		= { 0x91, 0xd0, 0x20, 0x7d },
diff --git a/arch/sparc/kernel/kgdb_64.c b/arch/sparc/kernel/kgdb_64.c
index 0a2bd0f99fc1..768290a6c028 100644
--- a/arch/sparc/kernel/kgdb_64.c
+++ b/arch/sparc/kernel/kgdb_64.c
@@ -181,6 +181,12 @@ void kgdb_arch_exit(void)
 {
 }
 
+void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
+{
+	regs->tpc = ip;
+	regs->tnpc = regs->tpc + 4;
+}
+
 struct kgdb_arch arch_kgdb_ops = {
 	/* Breakpoint instruction: ta 0x72 */
 	.gdb_bpt_instr		= { 0x91, 0xd0, 0x20, 0x72 },
diff --git a/arch/x86/include/asm/kgdb.h b/arch/x86/include/asm/kgdb.h
index e6c6c808489f..006da3687cdc 100644
--- a/arch/x86/include/asm/kgdb.h
+++ b/arch/x86/include/asm/kgdb.h
@@ -76,4 +76,7 @@ static inline void arch_kgdb_breakpoint(void)
 #define BREAK_INSTR_SIZE	1
 #define CACHE_FLUSH_IS_SAFE	1
 
+extern int kgdb_ll_trap(int cmd, const char *str,
+			struct pt_regs *regs, long err, int trap, int sig);
+
 #endif /* _ASM_X86_KGDB_H */
diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c
index b2258ca91003..95b89d4cb8f1 100644
--- a/arch/x86/kernel/kgdb.c
+++ b/arch/x86/kernel/kgdb.c
@@ -47,20 +47,8 @@
 #include <asm/debugreg.h>
 #include <asm/apicdef.h>
 #include <asm/system.h>
-
 #include <asm/apic.h>
 
-/*
- * Put the error code here just in case the user cares:
- */
-static int gdb_x86errcode;
-
-/*
- * Likewise, the vector number here (since GDB only gets the signal
- * number through the usual means, and that's not very specific):
- */
-static int gdb_x86vector = -1;
-
 /**
  *	pt_regs_to_gdb_regs - Convert ptrace regs to GDB regs
  *	@gdb_regs: A pointer to hold the registers in the order GDB wants.
@@ -399,23 +387,6 @@ void kgdb_disable_hw_debug(struct pt_regs *regs)
 	}
 }
 
-/**
- *	kgdb_post_primary_code - Save error vector/code numbers.
- *	@regs: Original pt_regs.
- *	@e_vector: Original error vector.
- *	@err_code: Original error code.
- *
- *	This is needed on architectures which support SMP and KGDB.
- *	This function is called after all the slave cpus have been put
- *	to a know spin state and the primary CPU has control over KGDB.
- */
-void kgdb_post_primary_code(struct pt_regs *regs, int e_vector, int err_code)
-{
-	/* primary processor is completely in the debugger */
-	gdb_x86vector = e_vector;
-	gdb_x86errcode = err_code;
-}
-
 #ifdef CONFIG_SMP
 /**
  *	kgdb_roundup_cpus - Get other CPUs into a holding pattern
@@ -567,7 +538,7 @@ static int __kgdb_notify(struct die_args *args, unsigned long cmd)
 			return NOTIFY_DONE;
 	}
 
-	if (kgdb_handle_exception(args->trapnr, args->signr, args->err, regs))
+	if (kgdb_handle_exception(args->trapnr, args->signr, cmd, regs))
 		return NOTIFY_DONE;
 
 	/* Must touch watchdog before return to normal operation */
@@ -575,6 +546,26 @@ static int __kgdb_notify(struct die_args *args, unsigned long cmd)
 	return NOTIFY_STOP;
 }
 
+#ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
+int kgdb_ll_trap(int cmd, const char *str,
+		 struct pt_regs *regs, long err, int trap, int sig)
+{
+	struct die_args args = {
+		.regs	= regs,
+		.str	= str,
+		.err	= err,
+		.trapnr	= trap,
+		.signr	= sig,
+
+	};
+
+	if (!kgdb_io_module_registered)
+		return NOTIFY_DONE;
+
+	return __kgdb_notify(&args, cmd);
+}
+#endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */
+
 static int
 kgdb_notify(struct notifier_block *self, unsigned long cmd, void *ptr)
 {
@@ -690,6 +681,11 @@ unsigned long kgdb_arch_pc(int exception, struct pt_regs *regs)
 	return instruction_pointer(regs);
 }
 
+void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long ip)
+{
+	regs->ip = ip;
+}
+
 struct kgdb_arch arch_kgdb_ops = {
 	/* Breakpoint instruction: */
 	.gdb_bpt_instr		= { 0xcc },
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index 02cfb9b8f5b1..7eaad4c5110a 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -15,6 +15,7 @@
 #include <linux/kprobes.h>
 #include <linux/uaccess.h>
 #include <linux/kdebug.h>
+#include <linux/kgdb.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/ptrace.h>
@@ -451,6 +452,11 @@ void restart_nmi(void)
 /* May run on IST stack. */
 dotraplinkage void __kprobes do_int3(struct pt_regs *regs, long error_code)
 {
+#ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
+	if (kgdb_ll_trap(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP)
+			== NOTIFY_STOP)
+		return;
+#endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */
 #ifdef CONFIG_KPROBES
 	if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP)
 			== NOTIFY_STOP)