Merge branch 'perf/core' into perf/uprobes

Merge in latest upstream (and the latest perf development tree),
to prepare for tooling changes, and also to pick up v3.4 MM
changes that the uprobes code needs to take care of.

Signed-off-by: Ingo Molnar <mingo@kernel.org>

9 files changed, 160 insertions, 58 deletions

diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c
index 0d7c08784ef..0557f24c6bc 100644
--- a/kernel/debug/debug_core.c
+++ b/kernel/debug/debug_core.c
@@ -41,6 +41,7 @@
 #include <linux/delay.h>
 #include <linux/sched.h>
 #include <linux/sysrq.h>
+#include <linux/reboot.h>
 #include <linux/init.h>
 #include <linux/kgdb.h>
 #include <linux/kdb.h>
@@ -52,7 +53,6 @@
 #include <asm/cacheflush.h>
 #include <asm/byteorder.h>
 #include <linux/atomic.h>
-#include <asm/system.h>
 
 #include "debug_core.h"
 
@@ -75,6 +75,8 @@ static int			exception_level;
 struct kgdb_io		*dbg_io_ops;
 static DEFINE_SPINLOCK(kgdb_registration_lock);
 
+/* Action for the reboot notifiter, a global allow kdb to change it */
+static int kgdbreboot;
 /* kgdb console driver is loaded */
 static int kgdb_con_registered;
 /* determine if kgdb console output should be used */
@@ -96,6 +98,7 @@ static int __init opt_kgdb_con(char *str)
 early_param("kgdbcon", opt_kgdb_con);
 
 module_param(kgdb_use_con, int, 0644);
+module_param(kgdbreboot, int, 0644);
 
 /*
  * Holds information about breakpoints in a kernel. These breakpoints are
@@ -157,37 +160,39 @@ early_param("nokgdbroundup", opt_nokgdbroundup);
  * Weak aliases for breakpoint management,
  * can be overriden by architectures when needed:
  */
-int __weak kgdb_arch_set_breakpoint(unsigned long addr, char *saved_instr)
+int __weak kgdb_arch_set_breakpoint(struct kgdb_bkpt *bpt)
 {
 	int err;
 
-	err = probe_kernel_read(saved_instr, (char *)addr, BREAK_INSTR_SIZE);
+	err = probe_kernel_read(bpt->saved_instr, (char *)bpt->bpt_addr,
+				BREAK_INSTR_SIZE);
 	if (err)
 		return err;
-
-	return probe_kernel_write((char *)addr, arch_kgdb_ops.gdb_bpt_instr,
-				  BREAK_INSTR_SIZE);
+	err = probe_kernel_write((char *)bpt->bpt_addr,
+				 arch_kgdb_ops.gdb_bpt_instr, BREAK_INSTR_SIZE);
+	return err;
 }
 
-int __weak kgdb_arch_remove_breakpoint(unsigned long addr, char *bundle)
+int __weak kgdb_arch_remove_breakpoint(struct kgdb_bkpt *bpt)
 {
-	return probe_kernel_write((char *)addr,
-				  (char *)bundle, BREAK_INSTR_SIZE);
+	return probe_kernel_write((char *)bpt->bpt_addr,
+				  (char *)bpt->saved_instr, BREAK_INSTR_SIZE);
 }
 
 int __weak kgdb_validate_break_address(unsigned long addr)
 {
-	char tmp_variable[BREAK_INSTR_SIZE];
+	struct kgdb_bkpt tmp;
 	int err;
-	/* Validate setting the breakpoint and then removing it.  In the
+	/* Validate setting the breakpoint and then removing it.  If the
 	 * remove fails, the kernel needs to emit a bad message because we
 	 * are deep trouble not being able to put things back the way we
 	 * found them.
 	 */
-	err = kgdb_arch_set_breakpoint(addr, tmp_variable);
+	tmp.bpt_addr = addr;
+	err = kgdb_arch_set_breakpoint(&tmp);
 	if (err)
 		return err;
-	err = kgdb_arch_remove_breakpoint(addr, tmp_variable);
+	err = kgdb_arch_remove_breakpoint(&tmp);
 	if (err)
 		printk(KERN_ERR "KGDB: Critical breakpoint error, kernel "
 		   "memory destroyed at: %lx", addr);
@@ -231,7 +236,6 @@ static void kgdb_flush_swbreak_addr(unsigned long addr)
  */
 int dbg_activate_sw_breakpoints(void)
 {
-	unsigned long addr;
 	int error;
 	int ret = 0;
 	int i;
@@ -240,16 +244,15 @@ int dbg_activate_sw_breakpoints(void)
 		if (kgdb_break[i].state != BP_SET)
 			continue;
 
-		addr = kgdb_break[i].bpt_addr;
-		error = kgdb_arch_set_breakpoint(addr,
-				kgdb_break[i].saved_instr);
+		error = kgdb_arch_set_breakpoint(&kgdb_break[i]);
 		if (error) {
 			ret = error;
-			printk(KERN_INFO "KGDB: BP install failed: %lx", addr);
+			printk(KERN_INFO "KGDB: BP install failed: %lx",
+			       kgdb_break[i].bpt_addr);
 			continue;
 		}
 
-		kgdb_flush_swbreak_addr(addr);
+		kgdb_flush_swbreak_addr(kgdb_break[i].bpt_addr);
 		kgdb_break[i].state = BP_ACTIVE;
 	}
 	return ret;
@@ -298,7 +301,6 @@ int dbg_set_sw_break(unsigned long addr)
 
 int dbg_deactivate_sw_breakpoints(void)
 {
-	unsigned long addr;
 	int error;
 	int ret = 0;
 	int i;
@@ -306,15 +308,14 @@ int dbg_deactivate_sw_breakpoints(void)
 	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
 		if (kgdb_break[i].state != BP_ACTIVE)
 			continue;
-		addr = kgdb_break[i].bpt_addr;
-		error = kgdb_arch_remove_breakpoint(addr,
-					kgdb_break[i].saved_instr);
+		error = kgdb_arch_remove_breakpoint(&kgdb_break[i]);
 		if (error) {
-			printk(KERN_INFO "KGDB: BP remove failed: %lx\n", addr);
+			printk(KERN_INFO "KGDB: BP remove failed: %lx\n",
+			       kgdb_break[i].bpt_addr);
 			ret = error;
 		}
 
-		kgdb_flush_swbreak_addr(addr);
+		kgdb_flush_swbreak_addr(kgdb_break[i].bpt_addr);
 		kgdb_break[i].state = BP_SET;
 	}
 	return ret;
@@ -348,7 +349,6 @@ int kgdb_isremovedbreak(unsigned long addr)
 
 int dbg_remove_all_break(void)
 {
-	unsigned long addr;
 	int error;
 	int i;
 
@@ -356,12 +356,10 @@ int dbg_remove_all_break(void)
 	for (i = 0; i < KGDB_MAX_BREAKPOINTS; i++) {
 		if (kgdb_break[i].state != BP_ACTIVE)
 			goto setundefined;
-		addr = kgdb_break[i].bpt_addr;
-		error = kgdb_arch_remove_breakpoint(addr,
-				kgdb_break[i].saved_instr);
+		error = kgdb_arch_remove_breakpoint(&kgdb_break[i]);
 		if (error)
 			printk(KERN_ERR "KGDB: breakpoint remove failed: %lx\n",
-			   addr);
+			       kgdb_break[i].bpt_addr);
 setundefined:
 		kgdb_break[i].state = BP_UNDEFINED;
 	}
@@ -784,6 +782,33 @@ void __init dbg_late_init(void)
 	kdb_init(KDB_INIT_FULL);
 }
 
+static int
+dbg_notify_reboot(struct notifier_block *this, unsigned long code, void *x)
+{
+	/*
+	 * Take the following action on reboot notify depending on value:
+	 *    1 == Enter debugger
+	 *    0 == [the default] detatch debug client
+	 *   -1 == Do nothing... and use this until the board resets
+	 */
+	switch (kgdbreboot) {
+	case 1:
+		kgdb_breakpoint();
+	case -1:
+		goto done;
+	}
+	if (!dbg_kdb_mode)
+		gdbstub_exit(code);
+done:
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block dbg_reboot_notifier = {
+	.notifier_call		= dbg_notify_reboot,
+	.next			= NULL,
+	.priority		= INT_MAX,
+};
+
 static void kgdb_register_callbacks(void)
 {
 	if (!kgdb_io_module_registered) {
@@ -791,6 +816,7 @@ static void kgdb_register_callbacks(void)
 		kgdb_arch_init();
 		if (!dbg_is_early)
 			kgdb_arch_late();
+		register_reboot_notifier(&dbg_reboot_notifier);
 		atomic_notifier_chain_register(&panic_notifier_list,
 					       &kgdb_panic_event_nb);
 #ifdef CONFIG_MAGIC_SYSRQ
@@ -812,6 +838,7 @@ static void kgdb_unregister_callbacks(void)
 	 */
 	if (kgdb_io_module_registered) {
 		kgdb_io_module_registered = 0;
+		unregister_reboot_notifier(&dbg_reboot_notifier);
 		atomic_notifier_chain_unregister(&panic_notifier_list,
 					       &kgdb_panic_event_nb);
 		kgdb_arch_exit();
diff --git a/kernel/debug/gdbstub.c b/kernel/debug/gdbstub.c
index c22d8c28ad8..ce615e06448 100644
--- a/kernel/debug/gdbstub.c
+++ b/kernel/debug/gdbstub.c
@@ -1111,6 +1111,13 @@ void gdbstub_exit(int status)
 	unsigned char checksum, ch, buffer[3];
 	int loop;
 
+	if (!kgdb_connected)
+		return;
+	kgdb_connected = 0;
+
+	if (!dbg_io_ops || dbg_kdb_mode)
+		return;
+
 	buffer[0] = 'W';
 	buffer[1] = hex_asc_hi(status);
 	buffer[2] = hex_asc_lo(status);
@@ -1129,5 +1136,6 @@ void gdbstub_exit(int status)
 	dbg_io_ops->write_char(hex_asc_lo(checksum));
 
 	/* make sure the output is flushed, lest the bootloader clobber it */
-	dbg_io_ops->flush();
+	if (dbg_io_ops->flush)
+		dbg_io_ops->flush();
 }
diff --git a/kernel/debug/kdb/kdb_bp.c b/kernel/debug/kdb/kdb_bp.c
index 20059ef4459..8418c2f8ec5 100644
--- a/kernel/debug/kdb/kdb_bp.c
+++ b/kernel/debug/kdb/kdb_bp.c
@@ -153,6 +153,13 @@ static int _kdb_bp_install(struct pt_regs *regs, kdb_bp_t *bp)
 	} else {
 		kdb_printf("%s: failed to set breakpoint at 0x%lx\n",
 			   __func__, bp->bp_addr);
+#ifdef CONFIG_DEBUG_RODATA
+		if (!bp->bp_type) {
+			kdb_printf("Software breakpoints are unavailable.\n"
+				   "  Change the kernel CONFIG_DEBUG_RODATA=n\n"
+				   "  OR use hw breaks: help bph\n");
+		}
+#endif
 		return 1;
 	}
 	return 0;
diff --git a/kernel/debug/kdb/kdb_bt.c b/kernel/debug/kdb/kdb_bt.c
index 7179eac7b41..07c9bbb94a0 100644
--- a/kernel/debug/kdb/kdb_bt.c
+++ b/kernel/debug/kdb/kdb_bt.c
@@ -15,7 +15,6 @@
 #include <linux/sched.h>
 #include <linux/kdb.h>
 #include <linux/nmi.h>
-#include <asm/system.h>
 #include "kdb_private.h"
 
 
diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index 4802eb5840e..bb9520f0f6f 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -689,7 +689,7 @@ kdb_printit:
 	if (!dbg_kdb_mode && kgdb_connected) {
 		gdbstub_msg_write(kdb_buffer, retlen);
 	} else {
-		if (!dbg_io_ops->is_console) {
+		if (dbg_io_ops && !dbg_io_ops->is_console) {
 			len = strlen(kdb_buffer);
 			cp = kdb_buffer;
 			while (len--) {
@@ -743,7 +743,7 @@ kdb_printit:
 		kdb_input_flush();
 		c = console_drivers;
 
-		if (!dbg_io_ops->is_console) {
+		if (dbg_io_ops && !dbg_io_ops->is_console) {
 			len = strlen(moreprompt);
 			cp = moreprompt;
 			while (len--) {
diff --git a/kernel/debug/kdb/kdb_keyboard.c b/kernel/debug/kdb/kdb_keyboard.c
index 4bca634975c..118527aa60e 100644
--- a/kernel/debug/kdb/kdb_keyboard.c
+++ b/kernel/debug/kdb/kdb_keyboard.c
@@ -25,6 +25,7 @@
 #define KBD_STAT_MOUSE_OBF	0x20	/* Mouse output buffer full */
 
 static int kbd_exists;
+static int kbd_last_ret;
 
 /*
  * Check if the keyboard controller has a keypress for us.
@@ -90,8 +91,11 @@ int kdb_get_kbd_char(void)
 		return -1;
 	}
 
-	if ((scancode & 0x80) != 0)
+	if ((scancode & 0x80) != 0) {
+		if (scancode == 0x9c)
+			kbd_last_ret = 0;
 		return -1;
+	}
 
 	scancode &= 0x7f;
 
@@ -178,35 +182,82 @@ int kdb_get_kbd_char(void)
 		return -1;	/* ignore unprintables */
 	}
 
-	if ((scancode & 0x7f) == 0x1c) {
-		/*
-		 * enter key.  All done.  Absorb the release scancode.
-		 */
+	if (scancode == 0x1c) {
+		kbd_last_ret = 1;
+		return 13;
+	}
+
+	return keychar & 0xff;
+}
+EXPORT_SYMBOL_GPL(kdb_get_kbd_char);
+
+/*
+ * Best effort cleanup of ENTER break codes on leaving KDB. Called on
+ * exiting KDB, when we know we processed an ENTER or KP ENTER scan
+ * code.
+ */
+void kdb_kbd_cleanup_state(void)
+{
+	int scancode, scanstatus;
+
+	/*
+	 * Nothing to clean up, since either
+	 * ENTER was never pressed, or has already
+	 * gotten cleaned up.
+	 */
+	if (!kbd_last_ret)
+		return;
+
+	kbd_last_ret = 0;
+	/*
+	 * Enter key. Need to absorb the break code here, lest it gets
+	 * leaked out if we exit KDB as the result of processing 'g'.
+	 *
+	 * This has several interesting implications:
+	 * + Need to handle KP ENTER, which has break code 0xe0 0x9c.
+	 * + Need to handle repeat ENTER and repeat KP ENTER. Repeats
+	 *   only get a break code at the end of the repeated
+	 *   sequence. This means we can't propagate the repeated key
+	 *   press, and must swallow it away.
+	 * + Need to handle possible PS/2 mouse input.
+	 * + Need to handle mashed keys.
+	 */
+
+	while (1) {
 		while ((inb(KBD_STATUS_REG) & KBD_STAT_OBF) == 0)
-			;
+			cpu_relax();
 
 		/*
-		 * Fetch the scancode
+		 * Fetch the scancode.
 		 */
 		scancode = inb(KBD_DATA_REG);
 		scanstatus = inb(KBD_STATUS_REG);
 
-		while (scanstatus & KBD_STAT_MOUSE_OBF) {
-			scancode = inb(KBD_DATA_REG);
-			scanstatus = inb(KBD_STATUS_REG);
-		}
+		/*
+		 * Skip mouse input.
+		 */
+		if (scanstatus & KBD_STAT_MOUSE_OBF)
+			continue;
 
-		if (scancode != 0x9c) {
-			/*
-			 * Wasn't an enter-release,  why not?
-			 */
-			kdb_printf("kdb: expected enter got 0x%x status 0x%x\n",
-			       scancode, scanstatus);
-		}
+		/*
+		 * If we see 0xe0, this is either a break code for KP
+		 * ENTER, or a repeat make for KP ENTER. Either way,
+		 * since the second byte is equivalent to an ENTER,
+		 * skip the 0xe0 and try again.
+		 *
+		 * If we see 0x1c, this must be a repeat ENTER or KP
+		 * ENTER (and we swallowed 0xe0 before). Try again.
+		 *
+		 * We can also see make and break codes for other keys
+		 * mashed before or after pressing ENTER. Thus, if we
+		 * see anything other than 0x9c, we have to try again.
+		 *
+		 * Note, if you held some key as ENTER was depressed,
+		 * that break code would get leaked out.
+		 */
+		if (scancode != 0x9c)
+			continue;
 
-		return 13;
+		return;
 	}
-
-	return keychar & 0xff;
 }
-EXPORT_SYMBOL_GPL(kdb_get_kbd_char);
diff --git a/kernel/debug/kdb/kdb_main.c b/kernel/debug/kdb/kdb_main.c
index e2ae7349437..67b847dfa2b 100644
--- a/kernel/debug/kdb/kdb_main.c
+++ b/kernel/debug/kdb/kdb_main.c
@@ -1400,6 +1400,9 @@ int kdb_main_loop(kdb_reason_t reason, kdb_reason_t reason2, int error,
 	if (KDB_STATE(DOING_SS))
 		KDB_STATE_CLEAR(SSBPT);
 
+	/* Clean up any keyboard devices before leaving */
+	kdb_kbd_cleanup_state();
+
 	return result;
 }
 
diff --git a/kernel/debug/kdb/kdb_private.h b/kernel/debug/kdb/kdb_private.h
index e381d105b40..47c4e56e513 100644
--- a/kernel/debug/kdb/kdb_private.h
+++ b/kernel/debug/kdb/kdb_private.h
@@ -246,6 +246,13 @@ extern void debug_kusage(void);
 
 extern void kdb_set_current_task(struct task_struct *);
 extern struct task_struct *kdb_current_task;
+
+#ifdef CONFIG_KDB_KEYBOARD
+extern void kdb_kbd_cleanup_state(void);
+#else /* ! CONFIG_KDB_KEYBOARD */
+#define kdb_kbd_cleanup_state()
+#endif /* ! CONFIG_KDB_KEYBOARD */
+
 #ifdef CONFIG_MODULES
 extern struct list_head *kdb_modules;
 #endif /* CONFIG_MODULES */
diff --git a/kernel/debug/kdb/kdb_support.c b/kernel/debug/kdb/kdb_support.c
index 7d6fb40d218..d35cc2d3a4c 100644
--- a/kernel/debug/kdb/kdb_support.c
+++ b/kernel/debug/kdb/kdb_support.c
@@ -384,9 +384,9 @@ static int kdb_getphys(void *res, unsigned long addr, size_t size)
 	if (!pfn_valid(pfn))
 		return 1;
 	page = pfn_to_page(pfn);
-	vaddr = kmap_atomic(page, KM_KDB);
+	vaddr = kmap_atomic(page);
 	memcpy(res, vaddr + (addr & (PAGE_SIZE - 1)), size);
-	kunmap_atomic(vaddr, KM_KDB);
+	kunmap_atomic(vaddr);
 
 	return 0;
 }