Merge branch 'dbg-early-merge' of git://git.kernel.org/pub/scm/linux/…

…kernel/git/jwessel/linux-2.6-kgdb

* 'dbg-early-merge' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/linux-2.6-kgdb:
  echi-dbgp: Add kernel debugger support for the usb debug port
  earlyprintk,vga,kdb: Fix \b and \r for earlyprintk=vga with kdb
  kgdboc: Add ekgdboc for early use of the kernel debugger
  x86,early dr regs,kgdb: Allow kernel debugger early dr register access
  x86,kgdb: Implement early hardware breakpoint debugging
  x86, kgdb, init: Add early and late debug states
  x86, kgdb: early trap init for early debug

Documentation/kernel-parameters.txt

@@ -713,6 +713,12 @@ and is between 256 and 4096 characters. It is defined in the file
 			The VGA output is eventually overwritten by the real
 			console.
 
+	ekgdboc=	[X86,KGDB] Allow early kernel console debugging
+			ekgdboc=kbd
+
+			This is desgined to be used in conjunction with
+			the boot argument: earlyprintk=vga
+
 	eata=		[HW,SCSI]
 
 	edd=		[EDD]
@@ -1121,6 +1127,17 @@ and is between 256 and 4096 characters. It is defined in the file
 			use the HighMem zone if it exists, and the Normal
 			zone if it does not.
 
+	kgdbdbgp=	[KGDB,HW] kgdb over EHCI usb debug port.
+			Format: <Controller#>[,poll interval]
+			The controller # is the number of the ehci usb debug
+			port as it is probed via PCI.  The poll interval is
+			optional and is the number seconds in between
+			each poll cycle to the debug port in case you need
+			the functionality for interrupting the kernel with
+			gdb or control-c on the dbgp connection.  When
+			not using this parameter you use sysrq-g to break into
+			the kernel debugger.
+
 	kgdboc=		[KGDB,HW] kgdb over consoles.
 			Requires a tty driver that supports console polling,
 			or a supported polling keyboard driver (non-usb).

arch/x86/include/asm/processor.h

@@ -789,6 +789,8 @@ static inline void wbinvd_halt(void)
 extern void enable_sep_cpu(void);
 extern int sysenter_setup(void);
 
+extern void early_trap_init(void);
+
 /* Defined in head.S */
 extern struct desc_ptr		early_gdt_descr;
 

arch/x86/kernel/cpu/common.c

@@ -1084,6 +1084,20 @@ static void clear_all_debug_regs(void)
 	}
 }
 
+#ifdef CONFIG_KGDB
+/*
+ * Restore debug regs if using kgdbwait and you have a kernel debugger
+ * connection established.
+ */
+static void dbg_restore_debug_regs(void)
+{
+	if (unlikely(kgdb_connected && arch_kgdb_ops.correct_hw_break))
+		arch_kgdb_ops.correct_hw_break();
+}
+#else /* ! CONFIG_KGDB */
+#define dbg_restore_debug_regs()
+#endif /* ! CONFIG_KGDB */
+
 /*
  * cpu_init() initializes state that is per-CPU. Some data is already
  * initialized (naturally) in the bootstrap process, such as the GDT
@@ -1174,18 +1188,8 @@ void __cpuinit cpu_init(void)
 	load_TR_desc();
 	load_LDT(&init_mm.context);
 
-#ifdef CONFIG_KGDB
-	/*
-	 * If the kgdb is connected no debug regs should be altered.  This
-	 * is only applicable when KGDB and a KGDB I/O module are built
-	 * into the kernel and you are using early debugging with
-	 * kgdbwait. KGDB will control the kernel HW breakpoint registers.
-	 */
-	if (kgdb_connected && arch_kgdb_ops.correct_hw_break)
-		arch_kgdb_ops.correct_hw_break();
-	else
-#endif
-		clear_all_debug_regs();
+	clear_all_debug_regs();
+	dbg_restore_debug_regs();
 
 	fpu_init();
 
@@ -1239,6 +1243,7 @@ void __cpuinit cpu_init(void)
 #endif
 
 	clear_all_debug_regs();
+	dbg_restore_debug_regs();
 
 	/*
 	 * Force FPU initialization:

arch/x86/kernel/early_printk.c

@@ -41,6 +41,14 @@ static void early_vga_write(struct console *con, const char *str, unsigned n)
 				writew(0x720, VGABASE + 2*(max_xpos*j + i));
 			current_ypos = max_ypos-1;
 		}
+#ifdef CONFIG_KGDB_KDB
+		if (c == '\b') {
+			if (current_xpos > 0)
+				current_xpos--;
+		} else if (c == '\r') {
+			current_xpos = 0;
+		} else
+#endif
 		if (c == '\n') {
 			current_xpos = 0;
 			current_ypos++;

arch/x86/kernel/kgdb.c

@@ -199,6 +199,8 @@ static struct hw_breakpoint {
 	struct perf_event	**pev;
 } breakinfo[4];
 
+static unsigned long early_dr7;
+
 static void kgdb_correct_hw_break(void)
 {
 	int breakno;
@@ -210,6 +212,14 @@ static void kgdb_correct_hw_break(void)
 		int cpu = raw_smp_processor_id();
 		if (!breakinfo[breakno].enabled)
 			continue;
+		if (dbg_is_early) {
+			set_debugreg(breakinfo[breakno].addr, breakno);
+			early_dr7 |= encode_dr7(breakno,
+						breakinfo[breakno].len,
+						breakinfo[breakno].type);
+			set_debugreg(early_dr7, 7);
+			continue;
+		}
 		bp = *per_cpu_ptr(breakinfo[breakno].pev, cpu);
 		info = counter_arch_bp(bp);
 		if (bp->attr.disabled != 1)
@@ -224,7 +234,8 @@ static void kgdb_correct_hw_break(void)
 		if (!val)
 			bp->attr.disabled = 0;
 	}
-	hw_breakpoint_restore();
+	if (!dbg_is_early)
+		hw_breakpoint_restore();
 }
 
 static int hw_break_reserve_slot(int breakno)
@@ -233,6 +244,9 @@ static int hw_break_reserve_slot(int breakno)
 	int cnt = 0;
 	struct perf_event **pevent;
 
+	if (dbg_is_early)
+		return 0;
+
 	for_each_online_cpu(cpu) {
 		cnt++;
 		pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu);
@@ -258,6 +272,9 @@ static int hw_break_release_slot(int breakno)
 	struct perf_event **pevent;
 	int cpu;
 
+	if (dbg_is_early)
+		return 0;
+
 	for_each_online_cpu(cpu) {
 		pevent = per_cpu_ptr(breakinfo[breakno].pev, cpu);
 		if (dbg_release_bp_slot(*pevent))
@@ -302,7 +319,11 @@ static void kgdb_remove_all_hw_break(void)
 		bp = *per_cpu_ptr(breakinfo[i].pev, cpu);
 		if (bp->attr.disabled == 1)
 			continue;
-		arch_uninstall_hw_breakpoint(bp);
+		if (dbg_is_early)
+			early_dr7 &= ~encode_dr7(i, breakinfo[i].len,
+						 breakinfo[i].type);
+		else
+			arch_uninstall_hw_breakpoint(bp);
 		bp->attr.disabled = 1;
 	}
 }
@@ -379,6 +400,11 @@ void kgdb_disable_hw_debug(struct pt_regs *regs)
 	for (i = 0; i < 4; i++) {
 		if (!breakinfo[i].enabled)
 			continue;
+		if (dbg_is_early) {
+			early_dr7 &= ~encode_dr7(i, breakinfo[i].len,
+						 breakinfo[i].type);
+			continue;
+		}
 		bp = *per_cpu_ptr(breakinfo[i].pev, cpu);
 		if (bp->attr.disabled == 1)
 			continue;
@@ -595,15 +621,16 @@ static struct notifier_block kgdb_notifier = {
  *	specific callbacks.
  */
 int kgdb_arch_init(void)
+{
+	return register_die_notifier(&kgdb_notifier);
+}
+
+void kgdb_arch_late(void)
 {
 	int i, cpu;
-	int ret;
 	struct perf_event_attr attr;
 	struct perf_event **pevent;
 
-	ret = register_die_notifier(&kgdb_notifier);
-	if (ret != 0)
-		return ret;
 	/*
 	 * Pre-allocate the hw breakpoint structions in the non-atomic
 	 * portion of kgdb because this operation requires mutexs to
@@ -615,12 +642,15 @@ int kgdb_arch_init(void)
 	attr.bp_type = HW_BREAKPOINT_W;
 	attr.disabled = 1;
 	for (i = 0; i < 4; i++) {
+		if (breakinfo[i].pev)
+			continue;
 		breakinfo[i].pev = register_wide_hw_breakpoint(&attr, NULL);
 		if (IS_ERR(breakinfo[i].pev)) {
-			printk(KERN_ERR "kgdb: Could not allocate hw breakpoints\n");
+			printk(KERN_ERR "kgdb: Could not allocate hw"
+			       "breakpoints\nDisabling the kernel debugger\n");
 			breakinfo[i].pev = NULL;
 			kgdb_arch_exit();
-			return -1;
+			return;
 		}
 		for_each_online_cpu(cpu) {
 			pevent = per_cpu_ptr(breakinfo[i].pev, cpu);
@@ -631,7 +661,6 @@ int kgdb_arch_init(void)
 			}
 		}
 	}
-	return ret;
 }
 
 /**

arch/x86/kernel/setup.c

@@ -725,6 +725,7 @@ void __init setup_arch(char **cmdline_p)
 	/* VMI may relocate the fixmap; do this before touching ioremap area */
 	vmi_init();
 
+	early_trap_init();
 	early_cpu_init();
 	early_ioremap_init();
 

arch/x86/kernel/traps.c

@@ -808,6 +808,16 @@ dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code)
 }
 #endif
 
+/* Set of traps needed for early debugging. */
+void __init early_trap_init(void)
+{
+	set_intr_gate_ist(1, &debug, DEBUG_STACK);
+	/* int3 can be called from all */
+	set_system_intr_gate_ist(3, &int3, DEBUG_STACK);
+	set_intr_gate(14, &page_fault);
+	load_idt(&idt_descr);
+}
+
 void __init trap_init(void)
 {
 	int i;
@@ -821,10 +831,7 @@ void __init trap_init(void)
 #endif
 
 	set_intr_gate(0, &divide_error);
-	set_intr_gate_ist(1, &debug, DEBUG_STACK);
 	set_intr_gate_ist(2, &nmi, NMI_STACK);
-	/* int3 can be called from all */
-	set_system_intr_gate_ist(3, &int3, DEBUG_STACK);
 	/* int4 can be called from all */
 	set_system_intr_gate(4, &overflow);
 	set_intr_gate(5, &bounds);
@@ -840,7 +847,6 @@ void __init trap_init(void)
 	set_intr_gate(11, &segment_not_present);
 	set_intr_gate_ist(12, &stack_segment, STACKFAULT_STACK);
 	set_intr_gate(13, &general_protection);
-	set_intr_gate(14, &page_fault);
 	set_intr_gate(15, &spurious_interrupt_bug);
 	set_intr_gate(16, &coprocessor_error);
 	set_intr_gate(17, &alignment_check);

drivers/serial/kgdboc.c

@@ -223,6 +223,25 @@ static struct kgdb_io kgdboc_io_ops = {
 	.post_exception		= kgdboc_post_exp_handler,
 };
 
+#ifdef CONFIG_KGDB_SERIAL_CONSOLE
+/* This is only available if kgdboc is a built in for early debugging */
+int __init kgdboc_early_init(char *opt)
+{
+	/* save the first character of the config string because the
+	 * init routine can destroy it.
+	 */
+	char save_ch;
+
+	kgdboc_option_setup(opt);
+	save_ch = config[0];
+	init_kgdboc();
+	config[0] = save_ch;
+	return 0;
+}
+
+early_param("ekgdboc", kgdboc_early_init);
+#endif /* CONFIG_KGDB_SERIAL_CONSOLE */
+
 module_init(init_kgdboc);
 module_exit(cleanup_kgdboc);
 module_param_call(kgdboc, param_set_kgdboc_var, param_get_string, &kps, 0644);