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Diffstat (limited to 'kernel/debug/kdb/kdb_debugger.c')
-rw-r--r--kernel/debug/kdb/kdb_debugger.c159
1 files changed, 159 insertions, 0 deletions
diff --git a/kernel/debug/kdb/kdb_debugger.c b/kernel/debug/kdb/kdb_debugger.c
new file mode 100644
index 000000000000..f024c0c4b8c4
--- /dev/null
+++ b/kernel/debug/kdb/kdb_debugger.c
@@ -0,0 +1,159 @@
+/*
+ * Created by: Jason Wessel <jason.wessel@windriver.com>
+ *
+ * Copyright (c) 2009 Wind River Systems, Inc. All Rights Reserved.
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/kgdb.h>
+#include <linux/kdb.h>
+#include <linux/kdebug.h>
+#include "kdb_private.h"
+#include "../debug_core.h"
+
+/*
+ * KDB interface to KGDB internals
+ */
+get_char_func kdb_poll_funcs[] = {
+ dbg_io_get_char,
+ NULL,
+};
+
+int kdb_stub(struct kgdb_state *ks)
+{
+ int error = 0;
+ kdb_bp_t *bp;
+ unsigned long addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs);
+ kdb_reason_t reason = KDB_REASON_OOPS;
+ kdb_dbtrap_t db_result = KDB_DB_NOBPT;
+ int i;
+
+ if (KDB_STATE(REENTRY)) {
+ reason = KDB_REASON_SWITCH;
+ KDB_STATE_CLEAR(REENTRY);
+ addr = instruction_pointer(ks->linux_regs);
+ }
+ ks->pass_exception = 0;
+ if (atomic_read(&kgdb_setting_breakpoint))
+ reason = KDB_REASON_KEYBOARD;
+
+ for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++) {
+ if ((bp->bp_enabled) && (bp->bp_addr == addr)) {
+ reason = KDB_REASON_BREAK;
+ db_result = KDB_DB_BPT;
+ if (addr != instruction_pointer(ks->linux_regs))
+ kgdb_arch_set_pc(ks->linux_regs, addr);
+ break;
+ }
+ }
+ if (reason == KDB_REASON_BREAK || reason == KDB_REASON_SWITCH) {
+ for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++) {
+ if (bp->bp_free)
+ continue;
+ if (bp->bp_addr == addr) {
+ bp->bp_delay = 1;
+ bp->bp_delayed = 1;
+ /*
+ * SSBPT is set when the kernel debugger must single step a
+ * task in order to re-establish an instruction breakpoint
+ * which uses the instruction replacement mechanism. It is
+ * cleared by any action that removes the need to single-step
+ * the breakpoint.
+ */
+ reason = KDB_REASON_BREAK;
+ db_result = KDB_DB_BPT;
+ KDB_STATE_SET(SSBPT);
+ break;
+ }
+ }
+ }
+
+ if (reason != KDB_REASON_BREAK && ks->ex_vector == 0 &&
+ ks->signo == SIGTRAP) {
+ reason = KDB_REASON_SSTEP;
+ db_result = KDB_DB_BPT;
+ }
+ /* Set initial kdb state variables */
+ KDB_STATE_CLEAR(KGDB_TRANS);
+ kdb_initial_cpu = ks->cpu;
+ kdb_current_task = kgdb_info[ks->cpu].task;
+ kdb_current_regs = kgdb_info[ks->cpu].debuggerinfo;
+ /* Remove any breakpoints as needed by kdb and clear single step */
+ kdb_bp_remove();
+ KDB_STATE_CLEAR(DOING_SS);
+ KDB_STATE_CLEAR(DOING_SSB);
+ /* zero out any offline cpu data */
+ for_each_present_cpu(i) {
+ if (!cpu_online(i)) {
+ kgdb_info[i].debuggerinfo = NULL;
+ kgdb_info[i].task = NULL;
+ }
+ }
+ if (ks->err_code == DIE_OOPS || reason == KDB_REASON_OOPS) {
+ ks->pass_exception = 1;
+ KDB_FLAG_SET(CATASTROPHIC);
+ }
+ kdb_initial_cpu = ks->cpu;
+ if (KDB_STATE(SSBPT) && reason == KDB_REASON_SSTEP) {
+ KDB_STATE_CLEAR(SSBPT);
+ KDB_STATE_CLEAR(DOING_SS);
+ } else {
+ /* Start kdb main loop */
+ error = kdb_main_loop(KDB_REASON_ENTER, reason,
+ ks->err_code, db_result, ks->linux_regs);
+ }
+ /*
+ * Upon exit from the kdb main loop setup break points and restart
+ * the system based on the requested continue state
+ */
+ kdb_initial_cpu = -1;
+ kdb_current_task = NULL;
+ kdb_current_regs = NULL;
+ kdbnearsym_cleanup();
+ if (error == KDB_CMD_KGDB) {
+ if (KDB_STATE(DOING_KGDB) || KDB_STATE(DOING_KGDB2)) {
+ /*
+ * This inteface glue which allows kdb to transition in into
+ * the gdb stub. In order to do this the '?' or '' gdb serial
+ * packet response is processed here. And then control is
+ * passed to the gdbstub.
+ */
+ if (KDB_STATE(DOING_KGDB))
+ gdbstub_state(ks, "?");
+ else
+ gdbstub_state(ks, "");
+ KDB_STATE_CLEAR(DOING_KGDB);
+ KDB_STATE_CLEAR(DOING_KGDB2);
+ }
+ return DBG_PASS_EVENT;
+ }
+ kdb_bp_install(ks->linux_regs);
+ dbg_activate_sw_breakpoints();
+ /* Set the exit state to a single step or a continue */
+ if (KDB_STATE(DOING_SS))
+ gdbstub_state(ks, "s");
+ else
+ gdbstub_state(ks, "c");
+
+ KDB_FLAG_CLEAR(CATASTROPHIC);
+
+ /* Invoke arch specific exception handling prior to system resume */
+ kgdb_info[ks->cpu].ret_state = gdbstub_state(ks, "e");
+ if (ks->pass_exception)
+ kgdb_info[ks->cpu].ret_state = 1;
+ if (error == KDB_CMD_CPU) {
+ KDB_STATE_SET(REENTRY);
+ /*
+ * Force clear the single step bit because kdb emulates this
+ * differently vs the gdbstub
+ */
+ kgdb_single_step = 0;
+ dbg_deactivate_sw_breakpoints();
+ return DBG_SWITCH_CPU_EVENT;
+ }
+ return kgdb_info[ks->cpu].ret_state;
+}
+

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