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linux/arch/mn10300/kernel/traps.c
David Howells db1c9dfa64 MN10300: die_if_no_fixup() shouldn't use get_user() as it doesn't call set_fs() 
die_if_no_fixup() shouldn't use get_user() as it doesn't call set_fs() to
indicate that it wants to probe a kernel address.  Instead it should use
probe_kernel_read().

This fixes the problem of gdb seeing SIGILL rather than SIGTRAP when hitting
the KGDB special breakpoint upon SysRq+g being seen.  The problem was that
die_if_no_fixup() was failing to read the opcode of the instruction that caused
the exception, and thus not fixing up the exception.

This caused gdb to get a S04 response to the $? request in its remote protocol
rather than S05 - which would then cause it to continue with $C04 rather than
$c in an attempt to pass the signal onto the inferior process.  The kernel,
however, does not support $Cnn, and so objects by returning an E22 response,
indicating an error.  gdb does not expect this and prints:

	warning: Remote failure reply: E22

and then returns to the gdb command prompt unable to continue.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-06-07 19:03:52 -07:00

628 lines
17 KiB
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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/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 <linux/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 <unit/leds.h>
#include <asm/fpu.h>
#include <asm/sections.h>
#include <asm/debugger.h>
#include "internal.h"
#if (CONFIG_INTERRUPT_VECTOR_BASE & 0xffffff)
#error "INTERRUPT_VECTOR_BASE not aligned to 16MiB boundary!"
#endif
int kstack_depth_to_print = 24;
spinlock_t die_lock = __SPIN_LOCK_UNLOCKED(die_lock);
struct exception_to_signal_map {
u8 signo;
u32 si_code;
};
static const struct exception_to_signal_map exception_to_signal_map[256] = {
/* MMU exceptions */
[EXCEP_ITLBMISS >> 3] = { 0, 0 },
[EXCEP_DTLBMISS >> 3] = { 0, 0 },
[EXCEP_IAERROR >> 3] = { 0, 0 },
[EXCEP_DAERROR >> 3] = { 0, 0 },
/* system exceptions */
[EXCEP_TRAP >> 3] = { SIGTRAP, TRAP_BRKPT },
[EXCEP_ISTEP >> 3] = { SIGTRAP, TRAP_TRACE }, /* Monitor */
[EXCEP_IBREAK >> 3] = { SIGTRAP, TRAP_HWBKPT }, /* Monitor */
[EXCEP_OBREAK >> 3] = { SIGTRAP, TRAP_HWBKPT }, /* Monitor */
[EXCEP_PRIVINS >> 3] = { SIGILL, ILL_PRVOPC },
[EXCEP_UNIMPINS >> 3] = { SIGILL, ILL_ILLOPC },
[EXCEP_UNIMPEXINS >> 3] = { SIGILL, ILL_ILLOPC },
[EXCEP_MEMERR >> 3] = { SIGSEGV, SEGV_ACCERR },
[EXCEP_MISALIGN >> 3] = { SIGBUS, BUS_ADRALN },
[EXCEP_BUSERROR >> 3] = { SIGBUS, BUS_ADRERR },
[EXCEP_ILLINSACC >> 3] = { SIGSEGV, SEGV_ACCERR },
[EXCEP_ILLDATACC >> 3] = { SIGSEGV, SEGV_ACCERR },
[EXCEP_IOINSACC >> 3] = { SIGSEGV, SEGV_ACCERR },
[EXCEP_PRIVINSACC >> 3] = { SIGSEGV, SEGV_ACCERR }, /* userspace */
[EXCEP_PRIVDATACC >> 3] = { SIGSEGV, SEGV_ACCERR }, /* userspace */
[EXCEP_DATINSACC >> 3] = { SIGSEGV, SEGV_ACCERR },
[EXCEP_DOUBLE_FAULT >> 3] = { SIGILL, ILL_BADSTK },
/* FPU exceptions */
[EXCEP_FPU_DISABLED >> 3] = { SIGILL, ILL_COPROC },
[EXCEP_FPU_UNIMPINS >> 3] = { SIGILL, ILL_COPROC },
[EXCEP_FPU_OPERATION >> 3] = { SIGFPE, FPE_INTDIV },
/* interrupts */
[EXCEP_WDT >> 3] = { SIGALRM, 0 },
[EXCEP_NMI >> 3] = { SIGQUIT, 0 },
[EXCEP_IRQ_LEVEL0 >> 3] = { SIGINT, 0 },
[EXCEP_IRQ_LEVEL1 >> 3] = { 0, 0 },
[EXCEP_IRQ_LEVEL2 >> 3] = { 0, 0 },
[EXCEP_IRQ_LEVEL3 >> 3] = { 0, 0 },
[EXCEP_IRQ_LEVEL4 >> 3] = { 0, 0 },
[EXCEP_IRQ_LEVEL5 >> 3] = { 0, 0 },
[EXCEP_IRQ_LEVEL6 >> 3] = { 0, 0 },
/* system calls */
[EXCEP_SYSCALL0 >> 3] = { 0, 0 },
[EXCEP_SYSCALL1 >> 3] = { SIGILL, ILL_ILLTRP },
[EXCEP_SYSCALL2 >> 3] = { SIGILL, ILL_ILLTRP },
[EXCEP_SYSCALL3 >> 3] = { SIGILL, ILL_ILLTRP },
[EXCEP_SYSCALL4 >> 3] = { SIGILL, ILL_ILLTRP },
[EXCEP_SYSCALL5 >> 3] = { SIGILL, ILL_ILLTRP },
[EXCEP_SYSCALL6 >> 3] = { SIGILL, ILL_ILLTRP },
[EXCEP_SYSCALL7 >> 3] = { SIGILL, ILL_ILLTRP },
[EXCEP_SYSCALL8 >> 3] = { SIGILL, ILL_ILLTRP },
[EXCEP_SYSCALL9 >> 3] = { SIGILL, ILL_ILLTRP },
[EXCEP_SYSCALL10 >> 3] = { SIGILL, ILL_ILLTRP },
[EXCEP_SYSCALL11 >> 3] = { SIGILL, ILL_ILLTRP },
[EXCEP_SYSCALL12 >> 3] = { SIGILL, ILL_ILLTRP },
[EXCEP_SYSCALL13 >> 3] = { SIGILL, ILL_ILLTRP },
[EXCEP_SYSCALL14 >> 3] = { SIGILL, ILL_ILLTRP },
[EXCEP_SYSCALL15 >> 3] = { SIGABRT, 0 },
};
/*
* Handle kernel exceptions.
*
* 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)
{
u8 opcode;
int signo, si_code;
if (user_mode(regs))
return 0;
peripheral_leds_display_exception(code);
signo = exception_to_signal_map[code >> 3].signo;
si_code = exception_to_signal_map[code >> 3].si_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;
break;
case EXCEP_TRAP:
case EXCEP_UNIMPINS:
if (probe_kernel_read(&opcode, (u8 *)regs->pc, 1) < 0)
break;
if (opcode == 0xff) {
if (notify_die(DIE_BREAKPOINT, str, regs, code, 0, 0))
return 1;
if (at_debugger_breakpoint(regs))
regs->pc++;
signo = SIGTRAP;
si_code = TRAP_BRKPT;
}
break;
case EXCEP_SYSCALL1 ... EXCEP_SYSCALL14:
/* syscall return addr is _after_ the instruction */
regs->pc -= 2;
break;
case EXCEP_SYSCALL15:
if (report_bug(regs->pc, regs) == BUG_TRAP_TYPE_WARN)
return 1;
/* syscall return addr is _after_ the instruction */
regs->pc -= 2;
break;
default:
break;
}
if (debugger_intercept(code, signo, si_code, regs) == 0)
return 1;
if (notify_die(DIE_GPF, str, regs, code, 0, 0))
return 1;
/* make the process die as the last resort */
die(str, regs, code);
}
/*
* General exception handler
*/
asmlinkage void handle_exception(struct pt_regs *regs, u32 intcode)
{
siginfo_t info;
/* deal with kernel exceptions here */
if (die_if_no_fixup(NULL, regs, intcode))
return;
/* otherwise it's a userspace exception */
info.si_signo = exception_to_signal_map[intcode >> 3].signo;
info.si_code = exception_to_signal_map[intcode >> 3].si_code;
info.si_errno = 0;
info.si_addr = (void *) regs->pc;
force_sig_info(info.si_signo, &info, current);
}
/*
* handle NMI
*/
asmlinkage void nmi(struct pt_regs *regs, enum exception_code code)
{
/* see if gdbstub wants to deal with it */
if (debugger_intercept(code, SIGQUIT, 0, regs))
return;
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 bottom, stack, addr, fp, raslot;
printk(KERN_EMERG "\nCall Trace:\n");
//stack = (unsigned long)sp;
asm("mov sp,%0" : "=a"(stack));
asm("mov a3,%0" : "=r"(fp));
raslot = ULONG_MAX;
bottom = (stack + THREAD_SIZE) & ~(THREAD_SIZE - 1);
for (; stack < bottom; stack += sizeof(addr)) {
addr = *(unsigned long *)stack;
if (stack == fp) {
if (addr > stack && addr < bottom) {
fp = addr;
raslot = stack + sizeof(addr);
continue;
}
fp = 0;
raslot = ULONG_MAX;
}
if (__kernel_text_address(addr)) {
printk(" [<%08lx>]", addr);
if (stack >= raslot)
raslot = ULONG_MAX;
else
printk(" ?");
print_symbol(" %s", addr);
printk("\n");
}
}
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(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 >= PAGE_OFFSET &&
(unsigned long) current < (unsigned long)high_memory)
printk(KERN_EMERG "Process %s (pid: %d)\n",
current->comm, current->pid);
#ifdef CONFIG_SMP
printk(KERN_EMERG "CPUID: %08x\n", CPUID);
#endif
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 "\nCode: ");
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%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 "\nPlease connect to kernel debugger !!\n");
asm volatile ("0: bra 0b");
}
spin_unlock_irq(&die_lock);
do_exit(SIGSEGV);
}
/*
* 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 "Asynchronous I/O Bus Error\n");
printk(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 */
if (debugger_intercept(code, SIGSYS, 0, regs) == 0)
return;
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);
unsigned long flags;
addr = (unsigned long) handler - (unsigned long) vector;
flags = arch_local_cli_save();
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;
arch_local_irq_restore(flags);
#ifndef CONFIG_MN10300_CACHE_SNOOP
mn10300_dcache_flush_inv();
mn10300_icache_inv();
#endif
}
/*
* initialise the exception table
*/
void __init trap_init(void)
{
set_excp_vector(EXCEP_TRAP, handle_exception);
set_excp_vector(EXCEP_ISTEP, handle_exception);
set_excp_vector(EXCEP_IBREAK, handle_exception);
set_excp_vector(EXCEP_OBREAK, handle_exception);
set_excp_vector(EXCEP_PRIVINS, handle_exception);
set_excp_vector(EXCEP_UNIMPINS, handle_exception);
set_excp_vector(EXCEP_UNIMPEXINS, handle_exception);
set_excp_vector(EXCEP_MEMERR, handle_exception);
set_excp_vector(EXCEP_MISALIGN, misalignment);
set_excp_vector(EXCEP_BUSERROR, handle_exception);
set_excp_vector(EXCEP_ILLINSACC, handle_exception);
set_excp_vector(EXCEP_ILLDATACC, handle_exception);
set_excp_vector(EXCEP_IOINSACC, handle_exception);
set_excp_vector(EXCEP_PRIVINSACC, handle_exception);
set_excp_vector(EXCEP_PRIVDATACC, handle_exception);
set_excp_vector(EXCEP_DATINSACC, handle_exception);
set_excp_vector(EXCEP_FPU_UNIMPINS, handle_exception);
set_excp_vector(EXCEP_FPU_OPERATION, fpu_exception);
set_excp_vector(EXCEP_NMI, nmi);
set_excp_vector(EXCEP_SYSCALL1, handle_exception);
set_excp_vector(EXCEP_SYSCALL2, handle_exception);
set_excp_vector(EXCEP_SYSCALL3, handle_exception);
set_excp_vector(EXCEP_SYSCALL4, handle_exception);
set_excp_vector(EXCEP_SYSCALL5, handle_exception);
set_excp_vector(EXCEP_SYSCALL6, handle_exception);
set_excp_vector(EXCEP_SYSCALL7, handle_exception);
set_excp_vector(EXCEP_SYSCALL8, handle_exception);
set_excp_vector(EXCEP_SYSCALL9, handle_exception);
set_excp_vector(EXCEP_SYSCALL10, handle_exception);
set_excp_vector(EXCEP_SYSCALL11, handle_exception);
set_excp_vector(EXCEP_SYSCALL12, handle_exception);
set_excp_vector(EXCEP_SYSCALL13, handle_exception);
set_excp_vector(EXCEP_SYSCALL14, handle_exception);
set_excp_vector(EXCEP_SYSCALL15, handle_exception);
}
/*
* 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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