diff options
| -rw-r--r-- | Documentation/DocBook/kgdb.tmpl | 17 | ||||
| -rw-r--r-- | arch/x86/include/asm/kgdb.h | 10 | ||||
| -rw-r--r-- | arch/x86/kernel/kgdb.c | 6 | ||||
| -rw-r--r-- | kernel/debug/debug_core.c | 33 | ||||
| -rw-r--r-- | kernel/debug/gdbstub.c | 10 | ||||
| -rw-r--r-- | kernel/debug/kdb/kdb_bp.c | 7 | ||||
| -rw-r--r-- | kernel/debug/kdb/kdb_io.c | 2 | ||||
| -rw-r--r-- | kernel/debug/kdb/kdb_keyboard.c | 95 | ||||
| -rw-r--r-- | kernel/debug/kdb/kdb_main.c | 3 | ||||
| -rw-r--r-- | kernel/debug/kdb/kdb_private.h | 7 |
10 files changed, 161 insertions, 29 deletions
diff --git a/Documentation/DocBook/kgdb.tmpl b/Documentation/DocBook/kgdb.tmpl index d71b57fcf116..4ee4ba3509fc 100644 --- a/Documentation/DocBook/kgdb.tmpl +++ b/Documentation/DocBook/kgdb.tmpl @@ -362,6 +362,23 @@ </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"> <title>Using kdb</title> diff --git a/arch/x86/include/asm/kgdb.h b/arch/x86/include/asm/kgdb.h index 77e95f54570a..332f98c9111f 100644 --- a/arch/x86/include/asm/kgdb.h +++ b/arch/x86/include/asm/kgdb.h @@ -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) diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c index faba5771acad..fdc37b3d0ce3 100644 --- a/arch/x86/kernel/kgdb.c +++ b/arch/x86/kernel/kgdb.c @@ -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) diff --git a/kernel/debug/debug_core.c b/kernel/debug/debug_core.c index 0d7c08784efb..3f88a45e6f0a 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> @@ -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(); diff --git a/kernel/debug/gdbstub.c b/kernel/debug/gdbstub.c index c22d8c28ad84..ce615e064482 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 20059ef4459a..8418c2f8ec5d 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_io.c b/kernel/debug/kdb/kdb_io.c index 4802eb5840e1..9b5f17da1c56 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--) { diff --git a/kernel/debug/kdb/kdb_keyboard.c b/kernel/debug/kdb/kdb_keyboard.c index 4bca634975c0..118527aa60ea 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 e2ae7349437f..67b847dfa2bb 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 e381d105b40b..47c4e56e513b 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 */ |