f5316b4aea
The design of the kdb shell requires that every device that can provide input to kdb have a polling routine that exits immediately if there is no character available. This is required in order to get the page scrolling mechanism working. Changing the kernel debugger I/O API to require all polling character routines to exit immediately if there is no data allows the kernel debugger to process multiple input channels. NO_POLL_CHAR will be the return code to the polling routine when ever there is no character available. CC: linux-serial@vger.kernel.org Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
169 lines
4.5 KiB
C
169 lines
4.5 KiB
C
/*
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* Created by: Jason Wessel <jason.wessel@windriver.com>
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*
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* Copyright (c) 2009 Wind River Systems, Inc. All Rights Reserved.
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*
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* This file is licensed under the terms of the GNU General Public
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* License version 2. This program is licensed "as is" without any
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* warranty of any kind, whether express or implied.
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*/
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#include <linux/kgdb.h>
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#include <linux/kdb.h>
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#include <linux/kdebug.h>
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#include "kdb_private.h"
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#include "../debug_core.h"
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/*
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* KDB interface to KGDB internals
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*/
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get_char_func kdb_poll_funcs[] = {
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dbg_io_get_char,
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NULL,
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NULL,
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NULL,
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NULL,
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NULL,
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};
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EXPORT_SYMBOL_GPL(kdb_poll_funcs);
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int kdb_poll_idx = 1;
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EXPORT_SYMBOL_GPL(kdb_poll_idx);
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int kdb_stub(struct kgdb_state *ks)
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{
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int error = 0;
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kdb_bp_t *bp;
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unsigned long addr = kgdb_arch_pc(ks->ex_vector, ks->linux_regs);
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kdb_reason_t reason = KDB_REASON_OOPS;
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kdb_dbtrap_t db_result = KDB_DB_NOBPT;
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int i;
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if (KDB_STATE(REENTRY)) {
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reason = KDB_REASON_SWITCH;
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KDB_STATE_CLEAR(REENTRY);
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addr = instruction_pointer(ks->linux_regs);
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}
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ks->pass_exception = 0;
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if (atomic_read(&kgdb_setting_breakpoint))
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reason = KDB_REASON_KEYBOARD;
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for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++) {
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if ((bp->bp_enabled) && (bp->bp_addr == addr)) {
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reason = KDB_REASON_BREAK;
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db_result = KDB_DB_BPT;
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if (addr != instruction_pointer(ks->linux_regs))
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kgdb_arch_set_pc(ks->linux_regs, addr);
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break;
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}
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}
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if (reason == KDB_REASON_BREAK || reason == KDB_REASON_SWITCH) {
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for (i = 0, bp = kdb_breakpoints; i < KDB_MAXBPT; i++, bp++) {
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if (bp->bp_free)
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continue;
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if (bp->bp_addr == addr) {
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bp->bp_delay = 1;
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bp->bp_delayed = 1;
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/*
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* SSBPT is set when the kernel debugger must single step a
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* task in order to re-establish an instruction breakpoint
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* which uses the instruction replacement mechanism. It is
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* cleared by any action that removes the need to single-step
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* the breakpoint.
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*/
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reason = KDB_REASON_BREAK;
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db_result = KDB_DB_BPT;
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KDB_STATE_SET(SSBPT);
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break;
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}
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}
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}
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if (reason != KDB_REASON_BREAK && ks->ex_vector == 0 &&
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ks->signo == SIGTRAP) {
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reason = KDB_REASON_SSTEP;
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db_result = KDB_DB_BPT;
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}
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/* Set initial kdb state variables */
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KDB_STATE_CLEAR(KGDB_TRANS);
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kdb_initial_cpu = ks->cpu;
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kdb_current_task = kgdb_info[ks->cpu].task;
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kdb_current_regs = kgdb_info[ks->cpu].debuggerinfo;
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/* Remove any breakpoints as needed by kdb and clear single step */
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kdb_bp_remove();
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KDB_STATE_CLEAR(DOING_SS);
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KDB_STATE_CLEAR(DOING_SSB);
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KDB_STATE_SET(PAGER);
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/* zero out any offline cpu data */
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for_each_present_cpu(i) {
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if (!cpu_online(i)) {
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kgdb_info[i].debuggerinfo = NULL;
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kgdb_info[i].task = NULL;
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}
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}
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if (ks->err_code == DIE_OOPS || reason == KDB_REASON_OOPS) {
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ks->pass_exception = 1;
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KDB_FLAG_SET(CATASTROPHIC);
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}
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kdb_initial_cpu = ks->cpu;
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if (KDB_STATE(SSBPT) && reason == KDB_REASON_SSTEP) {
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KDB_STATE_CLEAR(SSBPT);
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KDB_STATE_CLEAR(DOING_SS);
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} else {
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/* Start kdb main loop */
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error = kdb_main_loop(KDB_REASON_ENTER, reason,
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ks->err_code, db_result, ks->linux_regs);
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}
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/*
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* Upon exit from the kdb main loop setup break points and restart
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* the system based on the requested continue state
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*/
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kdb_initial_cpu = -1;
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kdb_current_task = NULL;
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kdb_current_regs = NULL;
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KDB_STATE_CLEAR(PAGER);
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kdbnearsym_cleanup();
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if (error == KDB_CMD_KGDB) {
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if (KDB_STATE(DOING_KGDB) || KDB_STATE(DOING_KGDB2)) {
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/*
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* This inteface glue which allows kdb to transition in into
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* the gdb stub. In order to do this the '?' or '' gdb serial
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* packet response is processed here. And then control is
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* passed to the gdbstub.
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*/
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if (KDB_STATE(DOING_KGDB))
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gdbstub_state(ks, "?");
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else
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gdbstub_state(ks, "");
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KDB_STATE_CLEAR(DOING_KGDB);
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KDB_STATE_CLEAR(DOING_KGDB2);
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}
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return DBG_PASS_EVENT;
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}
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kdb_bp_install(ks->linux_regs);
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dbg_activate_sw_breakpoints();
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/* Set the exit state to a single step or a continue */
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if (KDB_STATE(DOING_SS))
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gdbstub_state(ks, "s");
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else
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gdbstub_state(ks, "c");
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KDB_FLAG_CLEAR(CATASTROPHIC);
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/* Invoke arch specific exception handling prior to system resume */
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kgdb_info[ks->cpu].ret_state = gdbstub_state(ks, "e");
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if (ks->pass_exception)
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kgdb_info[ks->cpu].ret_state = 1;
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if (error == KDB_CMD_CPU) {
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KDB_STATE_SET(REENTRY);
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/*
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* Force clear the single step bit because kdb emulates this
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* differently vs the gdbstub
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*/
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kgdb_single_step = 0;
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dbg_deactivate_sw_breakpoints();
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return DBG_SWITCH_CPU_EVENT;
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}
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return kgdb_info[ks->cpu].ret_state;
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}
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