Commit a20ae85a authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'for_linus-3.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb 

Pull KGDB/KDB updates from Jason Wessel:
 "Fixes:
   - Fix KDB keyboard repeat scan codes and leaked keyboard events
   - Fix kernel crash with kdb_printf() for users who compile new
     kdb_printf()'s in early code
   - Return all segment registers to gdb on x86_64

  Features:
   - KDB/KGDB hook the reboot notifier and end user can control if it
     stops, detaches or does nothing (updated docs as well)
   - Notify users who use CONFIG_DEBUG_RODATA to use hw breakpoints"

* tag 'for_linus-3.4-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb:
  kdb: Add message about CONFIG_DEBUG_RODATA on failure to install breakpoint
  kdb: Avoid using dbg_io_ops until it is initialized
  kgdb,debug_core: add the ability to control the reboot notifier
  KDB: Fix usability issues relating to the 'enter' key.
  kgdb,debug-core,gdbstub: Hook the reboot notifier for debugger detach
  kgdb: Respect that flush op is optional
  kgdb: x86: Return all segment registers also in 64-bit mode
parents f0a5ec0e 1ba0c172

Documentation/DocBook/kgdb.tmpl

+17 −0
Original line number Diff line number Diff line
@@ -361,6 +361,23 @@ 
   <para>It is possible to use this option with kgdboc on a tty that is not a system console.

   </para>

  </para>

  </sect1>

   <sect1 id="kgdbreboot">

   <title>Run time parameter: kgdbreboot</title>

   <para> The kgdbreboot feature allows you to change how the debugger

   deals with the reboot notification.  You have 3 choices for the

   behavior.  The default behavior is always set to 0.</para>

   <orderedlist>

   <listitem><para>echo -1 > /sys/module/debug_core/parameters/kgdbreboot</para>

   <para>Ignore the reboot notification entirely.</para>

   </listitem>

   <listitem><para>echo 0 > /sys/module/debug_core/parameters/kgdbreboot</para>

   <para>Send the detach message to any attached debugger client.</para>

   </listitem>

   <listitem><para>echo 1 > /sys/module/debug_core/parameters/kgdbreboot</para>

   <para>Enter the debugger on reboot notify.</para>

   </listitem>

   </orderedlist>

  </sect1>

  </chapter>

  <chapter id="usingKDB">

arch/x86/include/asm/kgdb.h

+7 −3
Original line number Diff line number Diff line
@@ -64,11 +64,15 @@ enum regnames { 
	GDB_PS,			/* 17 */

	GDB_CS,			/* 18 */

	GDB_SS,			/* 19 */

	GDB_DS,			/* 20 */

	GDB_ES,			/* 21 */

	GDB_FS,			/* 22 */

	GDB_GS,			/* 23 */

};

#define GDB_ORIG_AX		57

#define DBG_MAX_REG_NUM		20

/* 17 64 bit regs and 3 32 bit regs */

#define NUMREGBYTES		((17 * 8) + (3 * 4))

#define DBG_MAX_REG_NUM		24

/* 17 64 bit regs and 5 32 bit regs */

#define NUMREGBYTES		((17 * 8) + (5 * 4))

#endif /* ! CONFIG_X86_32 */



static inline void arch_kgdb_breakpoint(void)

arch/x86/kernel/kgdb.c

+4 −2
Original line number Diff line number Diff line
@@ -67,8 +67,6 @@ struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = 
	{ "ss", 4, offsetof(struct pt_regs, ss) },

	{ "ds", 4, offsetof(struct pt_regs, ds) },

	{ "es", 4, offsetof(struct pt_regs, es) },

	{ "fs", 4, -1 },

	{ "gs", 4, -1 },

#else

	{ "ax", 8, offsetof(struct pt_regs, ax) },

	{ "bx", 8, offsetof(struct pt_regs, bx) },
@@ -90,7 +88,11 @@ struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] = 
	{ "flags", 4, offsetof(struct pt_regs, flags) },

	{ "cs", 4, offsetof(struct pt_regs, cs) },

	{ "ss", 4, offsetof(struct pt_regs, ss) },

	{ "ds", 4, -1 },

	{ "es", 4, -1 },

#endif

	{ "fs", 4, -1 },

	{ "gs", 4, -1 },

};



int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)

kernel/debug/debug_core.c

+33 −0
Original line number Diff line number Diff line
@@ -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>
@@ -75,6 +76,8 @@ 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 +99,7 @@ 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
@@ -784,6 +788,33 @@ 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 +822,7 @@ 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 +844,7 @@ 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();

kernel/debug/gdbstub.c

+9 −1
Original line number Diff line number Diff line
@@ -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 */

	if (dbg_io_ops->flush)

		dbg_io_ops->flush();

}

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