Commit 88547001 authored by Jason Wessel's avatar Jason Wessel Committed by Ralf Baechle

[MIPS] kgdb: add arch support for the kernel's kgdb core

The new kgdb architecture specific handler registers and unregisters
dynamically for exceptions depending on when you configure a kgdb I/O
driver.

Aside from initializing the exceptions earlier in the boot process,
kgdb should have no impact on a device when it is compiled in so long
as an I/O module is not configured for use.

There have been quite a number of contributors during the existence of
this patch (see arch/mips/kernel/kgdb.c).  Most recently Jason
re-wrote the mips kgdb logic to use the die notification handlers.
Signed-off-by: default avatarJason Wessel <jason.wessel@windriver.com>
Signed-off-by: default avatarRalf Baechle <ralf@linux-mips.org>
parent 8d60a903
...@@ -3,6 +3,7 @@ config MIPS ...@@ -3,6 +3,7 @@ config MIPS
default y default y
select HAVE_IDE select HAVE_IDE
select HAVE_OPROFILE select HAVE_OPROFILE
select HAVE_ARCH_KGDB
# Horrible source of confusion. Die, die, die ... # Horrible source of confusion. Die, die, die ...
select EMBEDDED select EMBEDDED
select RTC_LIB select RTC_LIB
......
...@@ -71,6 +71,7 @@ obj-$(CONFIG_MIPS32_COMPAT) += linux32.o ptrace32.o signal32.o ...@@ -71,6 +71,7 @@ obj-$(CONFIG_MIPS32_COMPAT) += linux32.o ptrace32.o signal32.o
obj-$(CONFIG_MIPS32_N32) += binfmt_elfn32.o scall64-n32.o signal_n32.o obj-$(CONFIG_MIPS32_N32) += binfmt_elfn32.o scall64-n32.o signal_n32.o
obj-$(CONFIG_MIPS32_O32) += binfmt_elfo32.o scall64-o32.o obj-$(CONFIG_MIPS32_O32) += binfmt_elfo32.o scall64-o32.o
obj-$(CONFIG_KGDB) += kgdb.o
obj-$(CONFIG_PROC_FS) += proc.o obj-$(CONFIG_PROC_FS) += proc.o
obj-$(CONFIG_64BIT) += cpu-bugs64.o obj-$(CONFIG_64BIT) += cpu-bugs64.o
......
...@@ -21,11 +21,16 @@ ...@@ -21,11 +21,16 @@
#include <linux/sched.h> #include <linux/sched.h>
#include <linux/seq_file.h> #include <linux/seq_file.h>
#include <linux/kallsyms.h> #include <linux/kallsyms.h>
#include <linux/kgdb.h>
#include <asm/atomic.h> #include <asm/atomic.h>
#include <asm/system.h> #include <asm/system.h>
#include <asm/uaccess.h> #include <asm/uaccess.h>
#ifdef CONFIG_KGDB
int kgdb_early_setup;
#endif
static unsigned long irq_map[NR_IRQS / BITS_PER_LONG]; static unsigned long irq_map[NR_IRQS / BITS_PER_LONG];
int allocate_irqno(void) int allocate_irqno(void)
...@@ -130,8 +135,18 @@ void __init init_IRQ(void) ...@@ -130,8 +135,18 @@ void __init init_IRQ(void)
{ {
int i; int i;
#ifdef CONFIG_KGDB
if (kgdb_early_setup)
return;
#endif
for (i = 0; i < NR_IRQS; i++) for (i = 0; i < NR_IRQS; i++)
set_irq_noprobe(i); set_irq_noprobe(i);
arch_init_irq(); arch_init_irq();
#ifdef CONFIG_KGDB
if (!kgdb_early_setup)
kgdb_early_setup = 1;
#endif
} }
/*
* 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(), (void *)0);
}
void kgdb_roundup_cpus(unsigned long flags)
{
local_irq_enable();
smp_call_function(kgdb_call_nmi_hook, NULL, NULL);
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;
if (fixup_exception(regs))
return NOTIFY_DONE;
/* 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')
if (kgdb_contthread)
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);
}
...@@ -23,6 +23,8 @@ ...@@ -23,6 +23,8 @@
#include <linux/bootmem.h> #include <linux/bootmem.h>
#include <linux/interrupt.h> #include <linux/interrupt.h>
#include <linux/ptrace.h> #include <linux/ptrace.h>
#include <linux/kgdb.h>
#include <linux/kdebug.h>
#include <asm/bootinfo.h> #include <asm/bootinfo.h>
#include <asm/branch.h> #include <asm/branch.h>
...@@ -425,6 +427,10 @@ asmlinkage void do_be(struct pt_regs *regs) ...@@ -425,6 +427,10 @@ asmlinkage void do_be(struct pt_regs *regs)
printk(KERN_ALERT "%s bus error, epc == %0*lx, ra == %0*lx\n", printk(KERN_ALERT "%s bus error, epc == %0*lx, ra == %0*lx\n",
data ? "Data" : "Instruction", data ? "Data" : "Instruction",
field, regs->cp0_epc, field, regs->regs[31]); field, regs->cp0_epc, field, regs->regs[31]);
if (notify_die(DIE_OOPS, "bus error", regs, SIGBUS, 0, 0)
== NOTIFY_STOP)
return;
die_if_kernel("Oops", regs); die_if_kernel("Oops", regs);
force_sig(SIGBUS, current); force_sig(SIGBUS, current);
} }
...@@ -623,6 +629,9 @@ asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31) ...@@ -623,6 +629,9 @@ asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
{ {
siginfo_t info; siginfo_t info;
if (notify_die(DIE_FP, "FP exception", regs, SIGFPE, 0, 0)
== NOTIFY_STOP)
return;
die_if_kernel("FP exception in kernel code", regs); die_if_kernel("FP exception in kernel code", regs);
if (fcr31 & FPU_CSR_UNI_X) { if (fcr31 & FPU_CSR_UNI_X) {
...@@ -682,6 +691,9 @@ static void do_trap_or_bp(struct pt_regs *regs, unsigned int code, ...@@ -682,6 +691,9 @@ static void do_trap_or_bp(struct pt_regs *regs, unsigned int code,
siginfo_t info; siginfo_t info;
char b[40]; char b[40];
if (notify_die(DIE_TRAP, str, regs, code, 0, 0) == NOTIFY_STOP)
return;
/* /*
* A short test says that IRIX 5.3 sends SIGTRAP for all trap * A short test says that IRIX 5.3 sends SIGTRAP for all trap
* insns, even for trap and break codes that indicate arithmetic * insns, even for trap and break codes that indicate arithmetic
...@@ -762,6 +774,10 @@ asmlinkage void do_ri(struct pt_regs *regs) ...@@ -762,6 +774,10 @@ asmlinkage void do_ri(struct pt_regs *regs)
unsigned int opcode = 0; unsigned int opcode = 0;
int status = -1; int status = -1;
if (notify_die(DIE_RI, "RI Fault", regs, SIGSEGV, 0, 0)
== NOTIFY_STOP)
return;
die_if_kernel("Reserved instruction in kernel code", regs); die_if_kernel("Reserved instruction in kernel code", regs);
if (unlikely(compute_return_epc(regs) < 0)) if (unlikely(compute_return_epc(regs) < 0))
...@@ -1537,6 +1553,11 @@ void __init trap_init(void) ...@@ -1537,6 +1553,11 @@ void __init trap_init(void)
extern char except_vec4; extern char except_vec4;
unsigned long i; unsigned long i;
#if defined(CONFIG_KGDB)
if (kgdb_early_setup)
return; /* Already done */
#endif
if (cpu_has_veic || cpu_has_vint) if (cpu_has_veic || cpu_has_vint)
ebase = (unsigned long) alloc_bootmem_low_pages(0x200 + VECTORSPACING*64); ebase = (unsigned long) alloc_bootmem_low_pages(0x200 + VECTORSPACING*64);
else else
......
#include <asm-generic/kdebug.h> #ifndef _ASM_MIPS_KDEBUG_H
#define _ASM_MIPS_KDEBUG_H
#include <linux/notifier.h>
enum die_val {
DIE_OOPS = 1,
DIE_FP,
DIE_TRAP,
DIE_RI,
};
#endif /* _ASM_MIPS_KDEBUG_H */
#ifndef __ASM_KGDB_H_
#define __ASM_KGDB_H_
#ifdef __KERNEL__
#include <asm/sgidefs.h>
#if (_MIPS_ISA == _MIPS_ISA_MIPS1) || (_MIPS_ISA == _MIPS_ISA_MIPS2) || \
(_MIPS_ISA == _MIPS_ISA_MIPS32)
#define KGDB_GDB_REG_SIZE 32
#elif (_MIPS_ISA == _MIPS_ISA_MIPS3) || (_MIPS_ISA == _MIPS_ISA_MIPS4) || \
(_MIPS_ISA == _MIPS_ISA_MIPS64)
#ifdef CONFIG_32BIT
#define KGDB_GDB_REG_SIZE 32
#else /* CONFIG_CPU_32BIT */
#define KGDB_GDB_REG_SIZE 64
#endif
#else
#error "Need to set KGDB_GDB_REG_SIZE for MIPS ISA"
#endif /* _MIPS_ISA */
#define BUFMAX 2048
#if (KGDB_GDB_REG_SIZE == 32)
#define NUMREGBYTES (90*sizeof(u32))
#define NUMCRITREGBYTES (12*sizeof(u32))
#else
#define NUMREGBYTES (90*sizeof(u64))
#define NUMCRITREGBYTES (12*sizeof(u64))
#endif
#define BREAK_INSTR_SIZE 4
#define CACHE_FLUSH_IS_SAFE 0
extern void arch_kgdb_breakpoint(void);
extern int kgdb_early_setup;
extern void *saved_vectors[32];
extern void handle_exception(struct pt_regs *regs);
extern void breakinst(void);
#endif /* __KERNEL__ */
#endif /* __ASM_KGDB_H_ */
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