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authorJason Wessel <jason.wessel@windriver.com>2010-05-20 21:04:21 -0500
committerJason Wessel <jason.wessel@windriver.com>2010-05-20 21:04:21 -0500
commit67fc4e0cb931d6b4ccf21248e4199b154478ecea (patch)
tree4cf49d00bc9ac03c3c77d91fadd13fcabc75e0c9 /kernel
parent5d5314d6795f3c1c0f415348ff8c51f7de042b77 (diff)
kdb: core for kgdb back end (2 of 2)
This patch contains the hooks and instrumentation into kernel which live outside the kernel/debug directory, which the kdb core will call to run commands like lsmod, dmesg, bt etc... CC: linux-arch@vger.kernel.org Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Signed-off-by: Martin Hicks <mort@sgi.com>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/kallsyms.c21
-rw-r--r--kernel/module.c4
-rw-r--r--kernel/printk.c16
-rw-r--r--kernel/sched.c7
-rw-r--r--kernel/signal.c40
5 files changed, 86 insertions, 2 deletions
diff --git a/kernel/kallsyms.c b/kernel/kallsyms.c
index 13aff293f4d..6f6d091b575 100644
--- a/kernel/kallsyms.c
+++ b/kernel/kallsyms.c
@@ -16,6 +16,7 @@
#include <linux/init.h>
#include <linux/seq_file.h>
#include <linux/fs.h>
+#include <linux/kdb.h>
#include <linux/err.h>
#include <linux/proc_fs.h>
#include <linux/sched.h> /* for cond_resched */
@@ -516,6 +517,26 @@ static int kallsyms_open(struct inode *inode, struct file *file)
return ret;
}
+#ifdef CONFIG_KGDB_KDB
+const char *kdb_walk_kallsyms(loff_t *pos)
+{
+ static struct kallsym_iter kdb_walk_kallsyms_iter;
+ if (*pos == 0) {
+ memset(&kdb_walk_kallsyms_iter, 0,
+ sizeof(kdb_walk_kallsyms_iter));
+ reset_iter(&kdb_walk_kallsyms_iter, 0);
+ }
+ while (1) {
+ if (!update_iter(&kdb_walk_kallsyms_iter, *pos))
+ return NULL;
+ ++*pos;
+ /* Some debugging symbols have no name. Ignore them. */
+ if (kdb_walk_kallsyms_iter.name[0])
+ return kdb_walk_kallsyms_iter.name;
+ }
+}
+#endif /* CONFIG_KGDB_KDB */
+
static const struct file_operations kallsyms_operations = {
.open = kallsyms_open,
.read = seq_read,
diff --git a/kernel/module.c b/kernel/module.c
index e2564580f3f..b751f190247 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -77,6 +77,10 @@
DEFINE_MUTEX(module_mutex);
EXPORT_SYMBOL_GPL(module_mutex);
static LIST_HEAD(modules);
+#ifdef CONFIG_KGDB_KDB
+struct list_head *kdb_modules = &modules; /* kdb needs the list of modules */
+#endif /* CONFIG_KGDB_KDB */
+
/* Block module loading/unloading? */
int modules_disabled = 0;
diff --git a/kernel/printk.c b/kernel/printk.c
index 75077ad0b53..9213b8b5bb4 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -413,6 +413,22 @@ SYSCALL_DEFINE3(syslog, int, type, char __user *, buf, int, len)
return do_syslog(type, buf, len, SYSLOG_FROM_CALL);
}
+#ifdef CONFIG_KGDB_KDB
+/* kdb dmesg command needs access to the syslog buffer. do_syslog()
+ * uses locks so it cannot be used during debugging. Just tell kdb
+ * where the start and end of the physical and logical logs are. This
+ * is equivalent to do_syslog(3).
+ */
+void kdb_syslog_data(char *syslog_data[4])
+{
+ syslog_data[0] = log_buf;
+ syslog_data[1] = log_buf + log_buf_len;
+ syslog_data[2] = log_buf + log_end -
+ (logged_chars < log_buf_len ? logged_chars : log_buf_len);
+ syslog_data[3] = log_buf + log_end;
+}
+#endif /* CONFIG_KGDB_KDB */
+
/*
* Call the console drivers on a range of log_buf
*/
diff --git a/kernel/sched.c b/kernel/sched.c
index 1d93cd0ae4d..a25c1324af5 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -7758,9 +7758,9 @@ void normalize_rt_tasks(void)
#endif /* CONFIG_MAGIC_SYSRQ */
-#ifdef CONFIG_IA64
+#if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
/*
- * These functions are only useful for the IA64 MCA handling.
+ * These functions are only useful for the IA64 MCA handling, or kdb.
*
* They can only be called when the whole system has been
* stopped - every CPU needs to be quiescent, and no scheduling
@@ -7780,6 +7780,9 @@ struct task_struct *curr_task(int cpu)
return cpu_curr(cpu);
}
+#endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
+
+#ifdef CONFIG_IA64
/**
* set_curr_task - set the current task for a given cpu.
* @cpu: the processor in question.
diff --git a/kernel/signal.c b/kernel/signal.c
index dbd7fe073c5..825a3f24ad7 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -2735,3 +2735,43 @@ void __init signals_init(void)
{
sigqueue_cachep = KMEM_CACHE(sigqueue, SLAB_PANIC);
}
+
+#ifdef CONFIG_KGDB_KDB
+#include <linux/kdb.h>
+/*
+ * kdb_send_sig_info - Allows kdb to send signals without exposing
+ * signal internals. This function checks if the required locks are
+ * available before calling the main signal code, to avoid kdb
+ * deadlocks.
+ */
+void
+kdb_send_sig_info(struct task_struct *t, struct siginfo *info)
+{
+ static struct task_struct *kdb_prev_t;
+ int sig, new_t;
+ if (!spin_trylock(&t->sighand->siglock)) {
+ kdb_printf("Can't do kill command now.\n"
+ "The sigmask lock is held somewhere else in "
+ "kernel, try again later\n");
+ return;
+ }
+ spin_unlock(&t->sighand->siglock);
+ new_t = kdb_prev_t != t;
+ kdb_prev_t = t;
+ if (t->state != TASK_RUNNING && new_t) {
+ kdb_printf("Process is not RUNNING, sending a signal from "
+ "kdb risks deadlock\n"
+ "on the run queue locks. "
+ "The signal has _not_ been sent.\n"
+ "Reissue the kill command if you want to risk "
+ "the deadlock.\n");
+ return;
+ }
+ sig = info->si_signo;
+ if (send_sig_info(sig, info, t))
+ kdb_printf("Fail to deliver Signal %d to process %d.\n",
+ sig, t->pid);
+ else
+ kdb_printf("Signal %d is sent to process %d.\n", sig, t->pid);
+}
+#endif /* CONFIG_KGDB_KDB */