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linux/arch/mn10300/kernel/traps.c
David Howells aa409e028c MN10300: Make the kernel jump into gdbstub on a BUG 
Make the kernel jump into gdbstub (if configured) on a BUG with the register
set from the BUG rather than interpolating another illegal instruction and
leaving gdbstub's idea of the process counter in unsupported_syscall() where
the original BUG was detected.

With this patch, gdbstub reports a SIGABRT to the compiler and reports the
program counter at the original BUG, allowing the execution state at the time
of the BUG to be examined with GDB.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-19 15:51:36 -08:00

620 lines
16 KiB
C
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/* MN10300 Exception handling
*
* Copyright (C) 2007 Matsushita Electric Industrial Co., Ltd.
* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
* Modified by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/smp_lock.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/kallsyms.h>
#include <linux/pci.h>
#include <linux/kdebug.h>
#include <linux/bug.h>
#include <linux/irq.h>
#include <asm/processor.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/atomic.h>
#include <asm/smp.h>
#include <asm/pgalloc.h>
#include <asm/cacheflush.h>
#include <asm/cpu-regs.h>
#include <asm/busctl-regs.h>
#include <asm/unit/leds.h>
#include <asm/fpu.h>
#include <asm/gdb-stub.h>
#include <asm/sections.h>
#if (CONFIG_INTERRUPT_VECTOR_BASE & 0xffffff)
#error "INTERRUPT_VECTOR_BASE not aligned to 16MiB boundary!"
#endif
struct pt_regs *__frame; /* current frame pointer */
EXPORT_SYMBOL(__frame);
int kstack_depth_to_print = 24;
spinlock_t die_lock = __SPIN_LOCK_UNLOCKED(die_lock);
ATOMIC_NOTIFIER_HEAD(mn10300_die_chain);
/*
* These constants are for searching for possible module text
* segments. MODULE_RANGE is a guess of how much space is likely
* to be vmalloced.
*/
#define MODULE_RANGE (8 * 1024 * 1024)
#define DO_ERROR(signr, prologue, str, name) \
asmlinkage void name(struct pt_regs *regs, u32 intcode) \
{ \
prologue; \
if (die_if_no_fixup(str, regs, intcode)) \
return; \
force_sig(signr, current); \
}
#define DO_EINFO(signr, prologue, str, name, sicode) \
asmlinkage void name(struct pt_regs *regs, u32 intcode) \
{ \
siginfo_t info; \
prologue; \
if (die_if_no_fixup(str, regs, intcode)) \
return; \
info.si_signo = signr; \
if (signr == SIGILL && sicode == ILL_ILLOPC) { \
uint8_t opcode; \
if (get_user(opcode, (uint8_t __user *)regs->pc) == 0) \
if (opcode == 0xff) \
info.si_signo = SIGTRAP; \
} \
info.si_errno = 0; \
info.si_code = sicode; \
info.si_addr = (void *) regs->pc; \
force_sig_info(info.si_signo, &info, current); \
}
DO_ERROR(SIGTRAP, {}, "trap", trap);
DO_ERROR(SIGSEGV, {}, "ibreak", ibreak);
DO_ERROR(SIGSEGV, {}, "obreak", obreak);
DO_EINFO(SIGSEGV, {}, "access error", access_error, SEGV_ACCERR);
DO_EINFO(SIGSEGV, {}, "insn access error", insn_acc_error, SEGV_ACCERR);
DO_EINFO(SIGSEGV, {}, "data access error", data_acc_error, SEGV_ACCERR);
DO_EINFO(SIGILL, {}, "privileged opcode", priv_op, ILL_PRVOPC);
DO_EINFO(SIGILL, {}, "invalid opcode", invalid_op, ILL_ILLOPC);
DO_EINFO(SIGILL, {}, "invalid ex opcode", invalid_exop, ILL_ILLOPC);
DO_EINFO(SIGBUS, {}, "invalid address", mem_error, BUS_ADRERR);
DO_EINFO(SIGBUS, {}, "bus error", bus_error, BUS_ADRERR);
DO_EINFO(SIGILL, {}, "FPU invalid opcode", fpu_invalid_op, ILL_COPROC);
DO_ERROR(SIGTRAP,
#ifndef CONFIG_MN10300_USING_JTAG
DCR &= ~0x0001,
#else
{},
#endif
"single step", istep);
/*
* handle NMI
*/
asmlinkage void nmi(struct pt_regs *regs, enum exception_code code)
{
/* see if gdbstub wants to deal with it */
#ifdef CONFIG_GDBSTUB
if (gdbstub_intercept(regs, code))
return;
#endif
printk(KERN_WARNING "--- Register Dump ---\n");
show_registers(regs);
printk(KERN_WARNING "---------------------\n");
}
/*
* show a stack trace from the specified stack pointer
*/
void show_trace(unsigned long *sp)
{
unsigned long *stack, addr, module_start, module_end;
int i;
printk(KERN_EMERG "\n"
KERN_EMERG "Call Trace:");
stack = sp;
i = 0;
module_start = VMALLOC_START;
module_end = VMALLOC_END;
while (((long) stack & (THREAD_SIZE - 1)) != 0) {
addr = *stack++;
if (__kernel_text_address(addr)) {
#if 1
printk(" [<%08lx>]", addr);
print_symbol(" %s", addr);
printk("\n");
#else
if ((i % 6) == 0)
printk("\n" KERN_EMERG " ");
printk("[<%08lx>] ", addr);
i++;
#endif
}
}
printk("\n");
}
/*
* show the raw stack from the specified stack pointer
*/
void show_stack(struct task_struct *task, unsigned long *sp)
{
unsigned long *stack;
int i;
if (!sp)
sp = (unsigned long *) &sp;
stack = sp;
printk(KERN_EMERG "Stack:");
for (i = 0; i < kstack_depth_to_print; i++) {
if (((long) stack & (THREAD_SIZE - 1)) == 0)
break;
if ((i % 8) == 0)
printk("\n" KERN_EMERG " ");
printk("%08lx ", *stack++);
}
show_trace(sp);
}
/*
* the architecture-independent dump_stack generator
*/
void dump_stack(void)
{
unsigned long stack;
show_stack(current, &stack);
}
EXPORT_SYMBOL(dump_stack);
/*
* dump the register file in the specified exception frame
*/
void show_registers_only(struct pt_regs *regs)
{
unsigned long ssp;
ssp = (unsigned long) regs + sizeof(*regs);
printk(KERN_EMERG "PC: %08lx EPSW: %08lx SSP: %08lx mode: %s\n",
regs->pc, regs->epsw, ssp, user_mode(regs) ? "User" : "Super");
printk(KERN_EMERG "d0: %08lx d1: %08lx d2: %08lx d3: %08lx\n",
regs->d0, regs->d1, regs->d2, regs->d3);
printk(KERN_EMERG "a0: %08lx a1: %08lx a2: %08lx a3: %08lx\n",
regs->a0, regs->a1, regs->a2, regs->a3);
printk(KERN_EMERG "e0: %08lx e1: %08lx e2: %08lx e3: %08lx\n",
regs->e0, regs->e1, regs->e2, regs->e3);
printk(KERN_EMERG "e4: %08lx e5: %08lx e6: %08lx e7: %08lx\n",
regs->e4, regs->e5, regs->e6, regs->e7);
printk(KERN_EMERG "lar: %08lx lir: %08lx mdr: %08lx usp: %08lx\n",
regs->lar, regs->lir, regs->mdr, regs->sp);
printk(KERN_EMERG "cvf: %08lx crl: %08lx crh: %08lx drq: %08lx\n",
regs->mcvf, regs->mcrl, regs->mcrh, regs->mdrq);
printk(KERN_EMERG "threadinfo=%p task=%p)\n",
current_thread_info(), current);
if ((unsigned long) current >= 0x90000000UL &&
(unsigned long) current < 0x94000000UL)
printk(KERN_EMERG "Process %s (pid: %d)\n",
current->comm, current->pid);
printk(KERN_EMERG "CPUP: %04hx\n", CPUP);
printk(KERN_EMERG "TBR: %08x\n", TBR);
printk(KERN_EMERG "DEAR: %08x\n", DEAR);
printk(KERN_EMERG "sISR: %08x\n", sISR);
printk(KERN_EMERG "NMICR: %04hx\n", NMICR);
printk(KERN_EMERG "BCBERR: %08x\n", BCBERR);
printk(KERN_EMERG "BCBEAR: %08x\n", BCBEAR);
printk(KERN_EMERG "MMUFCR: %08x\n", MMUFCR);
printk(KERN_EMERG "IPTEU : %08x IPTEL2: %08x\n", IPTEU, IPTEL2);
printk(KERN_EMERG "DPTEU: %08x DPTEL2: %08x\n", DPTEU, DPTEL2);
}
/*
* dump the registers and the stack
*/
void show_registers(struct pt_regs *regs)
{
unsigned long sp;
int i;
show_registers_only(regs);
if (!user_mode(regs))
sp = (unsigned long) regs + sizeof(*regs);
else
sp = regs->sp;
/* when in-kernel, we also print out the stack and code at the
* time of the fault..
*/
if (!user_mode(regs)) {
printk(KERN_EMERG "\n");
show_stack(current, (unsigned long *) sp);
#if 0
printk(KERN_EMERG "\n"
KERN_EMERG "Code: ");
if (regs->pc < PAGE_OFFSET)
goto bad;
for (i = 0; i < 20; i++) {
unsigned char c;
if (__get_user(c, &((unsigned char *) regs->pc)[i]))
goto bad;
printk("%02x ", c);
}
#else
i = 0;
#endif
}
printk("\n");
return;
#if 0
bad:
printk(KERN_EMERG " Bad PC value.");
break;
#endif
}
/*
*
*/
void show_trace_task(struct task_struct *tsk)
{
unsigned long sp = tsk->thread.sp;
/* User space on another CPU? */
if ((sp ^ (unsigned long) tsk) & (PAGE_MASK << 1))
return;
show_trace((unsigned long *) sp);
}
/*
* note the untimely death of part of the kernel
*/
void die(const char *str, struct pt_regs *regs, enum exception_code code)
{
console_verbose();
spin_lock_irq(&die_lock);
printk(KERN_EMERG "\n"
KERN_EMERG "%s: %04x\n",
str, code & 0xffff);
show_registers(regs);
if (regs->pc >= 0x02000000 && regs->pc < 0x04000000 &&
(regs->epsw & (EPSW_IM | EPSW_IE)) != (EPSW_IM | EPSW_IE)) {
printk(KERN_EMERG "Exception in usermode interrupt handler\n");
printk(KERN_EMERG "\n"
KERN_EMERG " Please connect to kernel debugger !!\n");
asm volatile ("0: bra 0b");
}
spin_unlock_irq(&die_lock);
do_exit(SIGSEGV);
}
/*
* see if there's a fixup handler we can force a jump to when an exception
* happens due to something kernel code did
*/
int die_if_no_fixup(const char *str, struct pt_regs *regs,
enum exception_code code)
{
if (user_mode(regs))
return 0;
peripheral_leds_display_exception(code);
switch (code) {
/* see if we can fixup the kernel accessing memory */
case EXCEP_ITLBMISS:
case EXCEP_DTLBMISS:
case EXCEP_IAERROR:
case EXCEP_DAERROR:
case EXCEP_MEMERR:
case EXCEP_MISALIGN:
case EXCEP_BUSERROR:
case EXCEP_ILLDATACC:
case EXCEP_IOINSACC:
case EXCEP_PRIVINSACC:
case EXCEP_PRIVDATACC:
case EXCEP_DATINSACC:
if (fixup_exception(regs))
return 1;
case EXCEP_UNIMPINS:
if (regs->pc && *(uint8_t *)regs->pc == 0xff)
if (notify_die(DIE_BREAKPOINT, str, regs, code, 0, 0))
return 1;
break;
default:
break;
}
/* see if gdbstub wants to deal with it */
#ifdef CONFIG_GDBSTUB
if (gdbstub_intercept(regs, code))
return 1;
#endif
if (notify_die(DIE_GPF, str, regs, code, 0, 0))
return 1;
/* make the process die as the last resort */
die(str, regs, code);
}
/*
* handle unsupported syscall instructions (syscall 1-15)
*/
static asmlinkage void unsupported_syscall(struct pt_regs *regs,
enum exception_code code)
{
struct task_struct *tsk = current;
siginfo_t info;
/* catch a kernel BUG() */
if (code == EXCEP_SYSCALL15 && !user_mode(regs)) {
if (report_bug(regs->pc, regs) == BUG_TRAP_TYPE_BUG) {
#ifdef CONFIG_GDBSTUB
gdbstub_intercept(regs, code);
#endif
}
}
regs->pc -= 2; /* syscall return addr is _after_ the instruction */
die_if_no_fixup("An unsupported syscall insn was used by the kernel\n",
regs, code);
info.si_signo = SIGILL;
info.si_errno = ENOSYS;
info.si_code = ILL_ILLTRP;
info.si_addr = (void *) regs->pc;
force_sig_info(SIGILL, &info, tsk);
}
/*
* display the register file when the stack pointer gets clobbered
*/
asmlinkage void do_double_fault(struct pt_regs *regs)
{
struct task_struct *tsk = current;
strcpy(tsk->comm, "emergency tsk");
tsk->pid = 0;
console_verbose();
printk(KERN_EMERG "--- double fault ---\n");
show_registers(regs);
}
/*
* asynchronous bus error (external, usually I/O DMA)
*/
asmlinkage void io_bus_error(u32 bcberr, u32 bcbear, struct pt_regs *regs)
{
console_verbose();
printk(KERN_EMERG "\n"
KERN_EMERG "Asynchronous I/O Bus Error\n"
KERN_EMERG "==========================\n");
if (bcberr & BCBERR_BEME)
printk(KERN_EMERG "- Multiple recorded errors\n");
printk(KERN_EMERG "- Faulting Buses:%s%s%s\n",
bcberr & BCBERR_BEMR_CI ? " CPU-Ins-Fetch" : "",
bcberr & BCBERR_BEMR_CD ? " CPU-Data" : "",
bcberr & BCBERR_BEMR_DMA ? " DMA" : "");
printk(KERN_EMERG "- %s %s access made to %s at address %08x\n",
bcberr & BCBERR_BEBST ? "Burst" : "Single",
bcberr & BCBERR_BERW ? "Read" : "Write",
bcberr & BCBERR_BESB_MON ? "Monitor Space" :
bcberr & BCBERR_BESB_IO ? "Internal CPU I/O Space" :
bcberr & BCBERR_BESB_EX ? "External I/O Bus" :
bcberr & BCBERR_BESB_OPEX ? "External Memory Bus" :
"On Chip Memory",
bcbear
);
printk(KERN_EMERG "- Detected by the %s\n",
bcberr&BCBERR_BESD ? "Bus Control Unit" : "Slave Bus");
#ifdef CONFIG_PCI
#define BRIDGEREGB(X) (*(volatile __u8 *)(0xBE040000 + (X)))
#define BRIDGEREGW(X) (*(volatile __u16 *)(0xBE040000 + (X)))
#define BRIDGEREGL(X) (*(volatile __u32 *)(0xBE040000 + (X)))
printk(KERN_EMERG "- PCI Memory Paging Reg: %08x\n",
*(volatile __u32 *) (0xBFFFFFF4));
printk(KERN_EMERG "- PCI Bridge Base Address 0: %08x\n",
BRIDGEREGL(PCI_BASE_ADDRESS_0));
printk(KERN_EMERG "- PCI Bridge AMPCI Base Address: %08x\n",
BRIDGEREGL(0x48));
printk(KERN_EMERG "- PCI Bridge Command: %04hx\n",
BRIDGEREGW(PCI_COMMAND));
printk(KERN_EMERG "- PCI Bridge Status: %04hx\n",
BRIDGEREGW(PCI_STATUS));
printk(KERN_EMERG "- PCI Bridge Int Status: %08hx\n",
BRIDGEREGL(0x4c));
#endif
printk(KERN_EMERG "\n");
show_registers(regs);
panic("Halted due to asynchronous I/O Bus Error\n");
}
/*
* handle an exception for which a handler has not yet been installed
*/
asmlinkage void uninitialised_exception(struct pt_regs *regs,
enum exception_code code)
{
/* see if gdbstub wants to deal with it */
#ifdef CONFIG_GDBSTUB
if (gdbstub_intercept(regs, code))
return;
#endif
peripheral_leds_display_exception(code);
printk(KERN_EMERG "Uninitialised Exception 0x%04x\n", code & 0xFFFF);
show_registers(regs);
for (;;)
continue;
}
/*
* set an interrupt stub to jump to a handler
* ! NOTE: this does *not* flush the caches
*/
void __init __set_intr_stub(enum exception_code code, void *handler)
{
unsigned long addr;
u8 *vector = (u8 *)(CONFIG_INTERRUPT_VECTOR_BASE + code);
addr = (unsigned long) handler - (unsigned long) vector;
vector[0] = 0xdc; /* JMP handler */
vector[1] = addr;
vector[2] = addr >> 8;
vector[3] = addr >> 16;
vector[4] = addr >> 24;
vector[5] = 0xcb;
vector[6] = 0xcb;
vector[7] = 0xcb;
}
/*
* set an interrupt stub to jump to a handler
*/
void __init set_intr_stub(enum exception_code code, void *handler)
{
unsigned long addr;
u8 *vector = (u8 *)(CONFIG_INTERRUPT_VECTOR_BASE + code);
addr = (unsigned long) handler - (unsigned long) vector;
vector[0] = 0xdc; /* JMP handler */
vector[1] = addr;
vector[2] = addr >> 8;
vector[3] = addr >> 16;
vector[4] = addr >> 24;
vector[5] = 0xcb;
vector[6] = 0xcb;
vector[7] = 0xcb;
mn10300_dcache_flush_inv();
mn10300_icache_inv();
}
/*
* set an interrupt stub to invoke the JTAG unit and then jump to a handler
*/
void __init set_jtag_stub(enum exception_code code, void *handler)
{
unsigned long addr;
u8 *vector = (u8 *)(CONFIG_INTERRUPT_VECTOR_BASE + code);
addr = (unsigned long) handler - ((unsigned long) vector + 1);
vector[0] = 0xff; /* PI to jump into JTAG debugger */
vector[1] = 0xdc; /* jmp handler */
vector[2] = addr;
vector[3] = addr >> 8;
vector[4] = addr >> 16;
vector[5] = addr >> 24;
vector[6] = 0xcb;
vector[7] = 0xcb;
mn10300_dcache_flush_inv();
flush_icache_range((unsigned long) vector, (unsigned long) vector + 8);
}
/*
* initialise the exception table
*/
void __init trap_init(void)
{
set_excp_vector(EXCEP_TRAP, trap);
set_excp_vector(EXCEP_ISTEP, istep);
set_excp_vector(EXCEP_IBREAK, ibreak);
set_excp_vector(EXCEP_OBREAK, obreak);
set_excp_vector(EXCEP_PRIVINS, priv_op);
set_excp_vector(EXCEP_UNIMPINS, invalid_op);
set_excp_vector(EXCEP_UNIMPEXINS, invalid_exop);
set_excp_vector(EXCEP_MEMERR, mem_error);
set_excp_vector(EXCEP_MISALIGN, misalignment);
set_excp_vector(EXCEP_BUSERROR, bus_error);
set_excp_vector(EXCEP_ILLINSACC, insn_acc_error);
set_excp_vector(EXCEP_ILLDATACC, data_acc_error);
set_excp_vector(EXCEP_IOINSACC, insn_acc_error);
set_excp_vector(EXCEP_PRIVINSACC, insn_acc_error);
set_excp_vector(EXCEP_PRIVDATACC, data_acc_error);
set_excp_vector(EXCEP_DATINSACC, insn_acc_error);
set_excp_vector(EXCEP_FPU_DISABLED, fpu_disabled);
set_excp_vector(EXCEP_FPU_UNIMPINS, fpu_invalid_op);
set_excp_vector(EXCEP_FPU_OPERATION, fpu_exception);
set_excp_vector(EXCEP_NMI, nmi);
set_excp_vector(EXCEP_SYSCALL1, unsupported_syscall);
set_excp_vector(EXCEP_SYSCALL2, unsupported_syscall);
set_excp_vector(EXCEP_SYSCALL3, unsupported_syscall);
set_excp_vector(EXCEP_SYSCALL4, unsupported_syscall);
set_excp_vector(EXCEP_SYSCALL5, unsupported_syscall);
set_excp_vector(EXCEP_SYSCALL6, unsupported_syscall);
set_excp_vector(EXCEP_SYSCALL7, unsupported_syscall);
set_excp_vector(EXCEP_SYSCALL8, unsupported_syscall);
set_excp_vector(EXCEP_SYSCALL9, unsupported_syscall);
set_excp_vector(EXCEP_SYSCALL10, unsupported_syscall);
set_excp_vector(EXCEP_SYSCALL11, unsupported_syscall);
set_excp_vector(EXCEP_SYSCALL12, unsupported_syscall);
set_excp_vector(EXCEP_SYSCALL13, unsupported_syscall);
set_excp_vector(EXCEP_SYSCALL14, unsupported_syscall);
set_excp_vector(EXCEP_SYSCALL15, unsupported_syscall);
}
/*
* determine if a program counter value is a valid bug address
*/
int is_valid_bugaddr(unsigned long pc)
{
return pc >= PAGE_OFFSET;
}
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