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-rw-r--r--arch/mips/kernel/kgdb.c277
1 files changed, 277 insertions, 0 deletions
diff --git a/arch/mips/kernel/kgdb.c b/arch/mips/kernel/kgdb.c
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+++ b/arch/mips/kernel/kgdb.c
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+/*
+ * Originally written by Glenn Engel, Lake Stevens Instrument Division
+ *
+ * Contributed by HP Systems
+ *
+ * Modified for Linux/MIPS (and MIPS in general) by Andreas Busse
+ * Send complaints, suggestions etc. to <andy@waldorf-gmbh.de>
+ *
+ * Copyright (C) 1995 Andreas Busse
+ *
+ * Copyright (C) 2003 MontaVista Software Inc.
+ * Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
+ *
+ * Copyright (C) 2004-2005 MontaVista Software Inc.
+ * Author: Manish Lachwani, mlachwani@mvista.com or manish@koffee-break.com
+ *
+ * Copyright (C) 2007-2008 Wind River Systems, Inc.
+ * Author/Maintainer: Jason Wessel, jason.wessel@windriver.com
+ *
+ * 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/ptrace.h> /* for linux pt_regs struct */
+#include <linux/kgdb.h>
+#include <linux/kdebug.h>
+#include <linux/sched.h>
+#include <asm/inst.h>
+#include <asm/fpu.h>
+#include <asm/cacheflush.h>
+#include <asm/processor.h>
+#include <asm/sigcontext.h>
+
+static struct hard_trap_info {
+ unsigned char tt; /* Trap type code for MIPS R3xxx and R4xxx */
+ unsigned char signo; /* Signal that we map this trap into */
+} hard_trap_info[] = {
+ { 6, SIGBUS }, /* instruction bus error */
+ { 7, SIGBUS }, /* data bus error */
+ { 9, SIGTRAP }, /* break */
+/* { 11, SIGILL }, */ /* CPU unusable */
+ { 12, SIGFPE }, /* overflow */
+ { 13, SIGTRAP }, /* trap */
+ { 14, SIGSEGV }, /* virtual instruction cache coherency */
+ { 15, SIGFPE }, /* floating point exception */
+ { 23, SIGSEGV }, /* watch */
+ { 31, SIGSEGV }, /* virtual data cache coherency */
+ { 0, 0} /* Must be last */
+};
+
+void arch_kgdb_breakpoint(void)
+{
+ __asm__ __volatile__(
+ ".globl breakinst\n\t"
+ ".set\tnoreorder\n\t"
+ "nop\n"
+ "breakinst:\tbreak\n\t"
+ "nop\n\t"
+ ".set\treorder");
+}
+
+static void kgdb_call_nmi_hook(void *ignored)
+{
+ kgdb_nmicallback(raw_smp_processor_id(), NULL);
+}
+
+void kgdb_roundup_cpus(unsigned long flags)
+{
+ local_irq_enable();
+ smp_call_function(kgdb_call_nmi_hook, NULL, 0);
+ local_irq_disable();
+}
+
+static int compute_signal(int tt)
+{
+ struct hard_trap_info *ht;
+
+ for (ht = hard_trap_info; ht->tt && ht->signo; ht++)
+ if (ht->tt == tt)
+ return ht->signo;
+
+ return SIGHUP; /* default for things we don't know about */
+}
+
+void pt_regs_to_gdb_regs(unsigned long *gdb_regs, struct pt_regs *regs)
+{
+ int reg;
+
+#if (KGDB_GDB_REG_SIZE == 32)
+ u32 *ptr = (u32 *)gdb_regs;
+#else
+ u64 *ptr = (u64 *)gdb_regs;
+#endif
+
+ for (reg = 0; reg < 32; reg++)
+ *(ptr++) = regs->regs[reg];
+
+ *(ptr++) = regs->cp0_status;
+ *(ptr++) = regs->lo;
+ *(ptr++) = regs->hi;
+ *(ptr++) = regs->cp0_badvaddr;
+ *(ptr++) = regs->cp0_cause;
+ *(ptr++) = regs->cp0_epc;
+
+ /* FP REGS */
+ if (!(current && (regs->cp0_status & ST0_CU1)))
+ return;
+
+ save_fp(current);
+ for (reg = 0; reg < 32; reg++)
+ *(ptr++) = current->thread.fpu.fpr[reg];
+}
+
+void gdb_regs_to_pt_regs(unsigned long *gdb_regs, struct pt_regs *regs)
+{
+ int reg;
+
+#if (KGDB_GDB_REG_SIZE == 32)
+ const u32 *ptr = (u32 *)gdb_regs;
+#else
+ const u64 *ptr = (u64 *)gdb_regs;
+#endif
+
+ for (reg = 0; reg < 32; reg++)
+ regs->regs[reg] = *(ptr++);
+
+ regs->cp0_status = *(ptr++);
+ regs->lo = *(ptr++);
+ regs->hi = *(ptr++);
+ regs->cp0_badvaddr = *(ptr++);
+ regs->cp0_cause = *(ptr++);
+ regs->cp0_epc = *(ptr++);
+
+ /* FP REGS from current */
+ if (!(current && (regs->cp0_status & ST0_CU1)))
+ return;
+
+ for (reg = 0; reg < 32; reg++)
+ current->thread.fpu.fpr[reg] = *(ptr++);
+ restore_fp(current);
+}
+
+/*
+ * Similar to regs_to_gdb_regs() except that process is sleeping and so
+ * we may not be able to get all the info.
+ */
+void sleeping_thread_to_gdb_regs(unsigned long *gdb_regs, struct task_struct *p)
+{
+ int reg;
+ struct thread_info *ti = task_thread_info(p);
+ unsigned long ksp = (unsigned long)ti + THREAD_SIZE - 32;
+ struct pt_regs *regs = (struct pt_regs *)ksp - 1;
+#if (KGDB_GDB_REG_SIZE == 32)
+ u32 *ptr = (u32 *)gdb_regs;
+#else
+ u64 *ptr = (u64 *)gdb_regs;
+#endif
+
+ for (reg = 0; reg < 16; reg++)
+ *(ptr++) = regs->regs[reg];
+
+ /* S0 - S7 */
+ for (reg = 16; reg < 24; reg++)
+ *(ptr++) = regs->regs[reg];
+
+ for (reg = 24; reg < 28; reg++)
+ *(ptr++) = 0;
+
+ /* GP, SP, FP, RA */
+ for (reg = 28; reg < 32; reg++)
+ *(ptr++) = regs->regs[reg];
+
+ *(ptr++) = regs->cp0_status;
+ *(ptr++) = regs->lo;
+ *(ptr++) = regs->hi;
+ *(ptr++) = regs->cp0_badvaddr;
+ *(ptr++) = regs->cp0_cause;
+ *(ptr++) = regs->cp0_epc;
+}
+
+/*
+ * Calls linux_debug_hook before the kernel dies. If KGDB is enabled,
+ * then try to fall into the debugger
+ */
+static int kgdb_mips_notify(struct notifier_block *self, unsigned long cmd,
+ void *ptr)
+{
+ struct die_args *args = (struct die_args *)ptr;
+ struct pt_regs *regs = args->regs;
+ int trap = (regs->cp0_cause & 0x7c) >> 2;
+
+ /* Userpace events, ignore. */
+ if (user_mode(regs))
+ return NOTIFY_DONE;
+
+ if (atomic_read(&kgdb_active) != -1)
+ kgdb_nmicallback(smp_processor_id(), regs);
+
+ if (kgdb_handle_exception(trap, compute_signal(trap), 0, regs))
+ return NOTIFY_DONE;
+
+ if (atomic_read(&kgdb_setting_breakpoint))
+ if ((trap == 9) && (regs->cp0_epc == (unsigned long)breakinst))
+ regs->cp0_epc += 4;
+
+ /* In SMP mode, __flush_cache_all does IPI */
+ local_irq_enable();
+ __flush_cache_all();
+
+ return NOTIFY_STOP;
+}
+
+static struct notifier_block kgdb_notifier = {
+ .notifier_call = kgdb_mips_notify,
+};
+
+/*
+ * Handle the 's' and 'c' commands
+ */
+int kgdb_arch_handle_exception(int vector, int signo, int err_code,
+ char *remcom_in_buffer, char *remcom_out_buffer,
+ struct pt_regs *regs)
+{
+ char *ptr;
+ unsigned long address;
+ int cpu = smp_processor_id();
+
+ switch (remcom_in_buffer[0]) {
+ case 's':
+ case 'c':
+ /* handle the optional parameter */
+ ptr = &remcom_in_buffer[1];
+ if (kgdb_hex2long(&ptr, &address))
+ regs->cp0_epc = address;
+
+ atomic_set(&kgdb_cpu_doing_single_step, -1);
+ if (remcom_in_buffer[0] == 's')
+ atomic_set(&kgdb_cpu_doing_single_step, cpu);
+
+ return 0;
+ }
+
+ return -1;
+}
+
+struct kgdb_arch arch_kgdb_ops;
+
+/*
+ * We use kgdb_early_setup so that functions we need to call now don't
+ * cause trouble when called again later.
+ */
+int kgdb_arch_init(void)
+{
+ union mips_instruction insn = {
+ .r_format = {
+ .opcode = spec_op,
+ .func = break_op,
+ }
+ };
+ memcpy(arch_kgdb_ops.gdb_bpt_instr, insn.byte, BREAK_INSTR_SIZE);
+
+ register_die_notifier(&kgdb_notifier);
+
+ return 0;
+}
+
+/*
+ * kgdb_arch_exit - Perform any architecture specific uninitalization.
+ *
+ * This function will handle the uninitalization of any architecture
+ * specific callbacks, for dynamic registration and unregistration.
+ */
+void kgdb_arch_exit(void)
+{
+ unregister_die_notifier(&kgdb_notifier);
+}
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