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-rw-r--r--arch/mips/kernel/kgdb.c415
1 files changed, 415 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 <linux/smp.h>
+#include <asm/inst.h>
+#include <asm/fpu.h>
+#include <asm/cacheflush.h>
+#include <asm/processor.h>
+#include <asm/sigcontext.h>
+#include <linux/uaccess.h>
+#include <asm/irq_regs.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 */
+};
+
+struct dbg_reg_def_t dbg_reg_def[DBG_MAX_REG_NUM] =
+{
+ { "zero", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[0]) },
+ { "at", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[1]) },
+ { "v0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[2]) },
+ { "v1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[3]) },
+ { "a0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[4]) },
+ { "a1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[5]) },
+ { "a2", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[6]) },
+ { "a3", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[7]) },
+ { "t0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[8]) },
+ { "t1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[9]) },
+ { "t2", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[10]) },
+ { "t3", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[11]) },
+ { "t4", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[12]) },
+ { "t5", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[13]) },
+ { "t6", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[14]) },
+ { "t7", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[15]) },
+ { "s0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[16]) },
+ { "s1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[17]) },
+ { "s2", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[18]) },
+ { "s3", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[19]) },
+ { "s4", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[20]) },
+ { "s5", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[21]) },
+ { "s6", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[22]) },
+ { "s7", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[23]) },
+ { "t8", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[24]) },
+ { "t9", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[25]) },
+ { "k0", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[26]) },
+ { "k1", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[27]) },
+ { "gp", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[28]) },
+ { "sp", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[29]) },
+ { "s8", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[30]) },
+ { "ra", GDB_SIZEOF_REG, offsetof(struct pt_regs, regs[31]) },
+ { "sr", GDB_SIZEOF_REG, offsetof(struct pt_regs, cp0_status) },
+ { "lo", GDB_SIZEOF_REG, offsetof(struct pt_regs, lo) },
+ { "hi", GDB_SIZEOF_REG, offsetof(struct pt_regs, hi) },
+ { "bad", GDB_SIZEOF_REG, offsetof(struct pt_regs, cp0_badvaddr) },
+ { "cause", GDB_SIZEOF_REG, offsetof(struct pt_regs, cp0_cause) },
+ { "pc", GDB_SIZEOF_REG, offsetof(struct pt_regs, cp0_epc) },
+ { "f0", GDB_SIZEOF_REG, 0 },
+ { "f1", GDB_SIZEOF_REG, 1 },
+ { "f2", GDB_SIZEOF_REG, 2 },
+ { "f3", GDB_SIZEOF_REG, 3 },
+ { "f4", GDB_SIZEOF_REG, 4 },
+ { "f5", GDB_SIZEOF_REG, 5 },
+ { "f6", GDB_SIZEOF_REG, 6 },
+ { "f7", GDB_SIZEOF_REG, 7 },
+ { "f8", GDB_SIZEOF_REG, 8 },
+ { "f9", GDB_SIZEOF_REG, 9 },
+ { "f10", GDB_SIZEOF_REG, 10 },
+ { "f11", GDB_SIZEOF_REG, 11 },
+ { "f12", GDB_SIZEOF_REG, 12 },
+ { "f13", GDB_SIZEOF_REG, 13 },
+ { "f14", GDB_SIZEOF_REG, 14 },
+ { "f15", GDB_SIZEOF_REG, 15 },
+ { "f16", GDB_SIZEOF_REG, 16 },
+ { "f17", GDB_SIZEOF_REG, 17 },
+ { "f18", GDB_SIZEOF_REG, 18 },
+ { "f19", GDB_SIZEOF_REG, 19 },
+ { "f20", GDB_SIZEOF_REG, 20 },
+ { "f21", GDB_SIZEOF_REG, 21 },
+ { "f22", GDB_SIZEOF_REG, 22 },
+ { "f23", GDB_SIZEOF_REG, 23 },
+ { "f24", GDB_SIZEOF_REG, 24 },
+ { "f25", GDB_SIZEOF_REG, 25 },
+ { "f26", GDB_SIZEOF_REG, 26 },
+ { "f27", GDB_SIZEOF_REG, 27 },
+ { "f28", GDB_SIZEOF_REG, 28 },
+ { "f29", GDB_SIZEOF_REG, 29 },
+ { "f30", GDB_SIZEOF_REG, 30 },
+ { "f31", GDB_SIZEOF_REG, 31 },
+ { "fsr", GDB_SIZEOF_REG, 0 },
+ { "fir", GDB_SIZEOF_REG, 0 },
+};
+
+int dbg_set_reg(int regno, void *mem, struct pt_regs *regs)
+{
+ int fp_reg;
+
+ if (regno < 0 || regno >= DBG_MAX_REG_NUM)
+ return -EINVAL;
+
+ if (dbg_reg_def[regno].offset != -1 && regno < 38) {
+ memcpy((void *)regs + dbg_reg_def[regno].offset, mem,
+ dbg_reg_def[regno].size);
+ } else if (current && dbg_reg_def[regno].offset != -1 && regno < 72) {
+ /* FP registers 38 -> 69 */
+ if (!(regs->cp0_status & ST0_CU1))
+ return 0;
+ if (regno == 70) {
+ /* Process the fcr31/fsr (register 70) */
+ memcpy((void *)&current->thread.fpu.fcr31, mem,
+ dbg_reg_def[regno].size);
+ goto out_save;
+ } else if (regno == 71) {
+ /* Ignore the fir (register 71) */
+ goto out_save;
+ }
+ fp_reg = dbg_reg_def[regno].offset;
+ memcpy((void *)&current->thread.fpu.fpr[fp_reg], mem,
+ dbg_reg_def[regno].size);
+out_save:
+ restore_fp(current);
+ }
+
+ return 0;
+}
+
+char *dbg_get_reg(int regno, void *mem, struct pt_regs *regs)
+{
+ int fp_reg;
+
+ if (regno >= DBG_MAX_REG_NUM || regno < 0)
+ return NULL;
+
+ if (dbg_reg_def[regno].offset != -1 && regno < 38) {
+ /* First 38 registers */
+ memcpy(mem, (void *)regs + dbg_reg_def[regno].offset,
+ dbg_reg_def[regno].size);
+ } else if (current && dbg_reg_def[regno].offset != -1 && regno < 72) {
+ /* FP registers 38 -> 69 */
+ if (!(regs->cp0_status & ST0_CU1))
+ goto out;
+ save_fp(current);
+ if (regno == 70) {
+ /* Process the fcr31/fsr (register 70) */
+ memcpy(mem, (void *)&current->thread.fpu.fcr31,
+ dbg_reg_def[regno].size);
+ goto out;
+ } else if (regno == 71) {
+ /* Ignore the fir (register 71) */
+ memset(mem, 0, dbg_reg_def[regno].size);
+ goto out;
+ }
+ fp_reg = dbg_reg_def[regno].offset;
+ memcpy(mem, (void *)&current->thread.fpu.fpr[fp_reg],
+ dbg_reg_def[regno].size);
+ }
+
+out:
+ return dbg_reg_def[regno].name;
+
+}
+
+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");
+}
+
+void kgdb_call_nmi_hook(void *ignored)
+{
+ mm_segment_t old_fs;
+
+ old_fs = get_fs();
+ set_fs(KERNEL_DS);
+
+ kgdb_nmicallback(raw_smp_processor_id(), get_irq_regs());
+
+ set_fs(old_fs);
+}
+
+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 */
+}
+
+/*
+ * 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;
+#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++) = 0;
+
+ /* S0 - S7 */
+ *(ptr++) = p->thread.reg16;
+ *(ptr++) = p->thread.reg17;
+ *(ptr++) = p->thread.reg18;
+ *(ptr++) = p->thread.reg19;
+ *(ptr++) = p->thread.reg20;
+ *(ptr++) = p->thread.reg21;
+ *(ptr++) = p->thread.reg22;
+ *(ptr++) = p->thread.reg23;
+
+ for (reg = 24; reg < 28; reg++)
+ *(ptr++) = 0;
+
+ /* GP, SP, FP, RA */
+ *(ptr++) = (long)p;
+ *(ptr++) = p->thread.reg29;
+ *(ptr++) = p->thread.reg30;
+ *(ptr++) = p->thread.reg31;
+
+ *(ptr++) = p->thread.cp0_status;
+
+ /* lo, hi */
+ *(ptr++) = 0;
+ *(ptr++) = 0;
+
+ /*
+ * BadVAddr, Cause
+ * Ideally these would come from the last exception frame up the stack
+ * but that requires unwinding, otherwise we can't know much for sure.
+ */
+ *(ptr++) = 0;
+ *(ptr++) = 0;
+
+ /*
+ * PC
+ * use return address (RA), i.e. the moment after return from resume()
+ */
+ *(ptr++) = p->thread.reg31;
+}
+
+void kgdb_arch_set_pc(struct pt_regs *regs, unsigned long pc)
+{
+ regs->cp0_epc = pc;
+}
+
+/*
+ * 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;
+ mm_segment_t old_fs;
+
+#ifdef CONFIG_KPROBES
+ /*
+ * Return immediately if the kprobes fault notifier has set
+ * DIE_PAGE_FAULT.
+ */
+ if (cmd == DIE_PAGE_FAULT)
+ return NOTIFY_DONE;
+#endif /* CONFIG_KPROBES */
+
+ /* Userspace events, ignore. */
+ if (user_mode(regs))
+ return NOTIFY_DONE;
+
+ /* Kernel mode. Set correct address limit */
+ old_fs = get_fs();
+ set_fs(KERNEL_DS);
+
+ if (atomic_read(&kgdb_active) != -1)
+ kgdb_nmicallback(smp_processor_id(), regs);
+
+ if (kgdb_handle_exception(trap, compute_signal(trap), cmd, regs)) {
+ set_fs(old_fs);
+ 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();
+
+ set_fs(old_fs);
+ return NOTIFY_STOP;
+}
+
+#ifdef CONFIG_KGDB_LOW_LEVEL_TRAP
+int kgdb_ll_trap(int cmd, const char *str,
+ struct pt_regs *regs, long err, int trap, int sig)
+{
+ struct die_args args = {
+ .regs = regs,
+ .str = str,
+ .err = err,
+ .trapnr = trap,
+ .signr = sig,
+
+ };
+
+ if (!kgdb_io_module_registered)
+ return NOTIFY_DONE;
+
+ return kgdb_mips_notify(NULL, cmd, &args);
+}
+#endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */
+
+static struct notifier_block kgdb_notifier = {
+ .notifier_call = kgdb_mips_notify,
+};
+
+/*
+ * Handle the 'c' command
+ */
+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;
+
+ switch (remcom_in_buffer[0]) {
+ case 'c':
+ /* handle the optional parameter */
+ ptr = &remcom_in_buffer[1];
+ if (kgdb_hex2long(&ptr, &address))
+ regs->cp0_epc = address;
+
+ return 0;
+ }
+
+ return -1;
+}
+
+const struct kgdb_arch arch_kgdb_ops = {
+#ifdef CONFIG_CPU_BIG_ENDIAN
+ .gdb_bpt_instr = { spec_op << 2, 0x00, 0x00, break_op },
+#else
+ .gdb_bpt_instr = { break_op, 0x00, 0x00, spec_op << 2 },
+#endif
+};
+
+int kgdb_arch_init(void)
+{
+ 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);
+}