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linux/arch/s390/kernel/traps.c
Heiko Carstens 02834eece0 [S390] Enable exception traces by default 
Enable exception traces by default so that early user space breakage
(e.g. broken code in initrd) can be easily indentified.

If not needed afterwards it can be disabled by writing '0' in one of
these two files:

/proc/sys/kernel/userprocess_debug
/proc/sys/debug/exception-trace

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-12-27 11:27:14 +01:00

656 lines
19 KiB
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/*
* arch/s390/kernel/traps.c
*
* S390 version
* Copyright (C) 1999,2000 IBM Deutschland Entwicklung GmbH, IBM Corporation
* Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com),
* Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
*
* Derived from "arch/i386/kernel/traps.c"
* Copyright (C) 1991, 1992 Linus Torvalds
*/
/*
* 'Traps.c' handles hardware traps and faults after we have saved some
* state in 'asm.s'.
*/
#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/interrupt.h>
#include <linux/seq_file.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/kdebug.h>
#include <linux/kallsyms.h>
#include <linux/reboot.h>
#include <linux/kprobes.h>
#include <linux/bug.h>
#include <linux/utsname.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <linux/atomic.h>
#include <asm/mathemu.h>
#include <asm/cpcmd.h>
#include <asm/lowcore.h>
#include <asm/debug.h>
#include "entry.h"
void (*pgm_check_table[128])(struct pt_regs *regs);
int show_unhandled_signals = 1;
#define stack_pointer ({ void **sp; asm("la %0,0(15)" : "=&d" (sp)); sp; })
#ifndef CONFIG_64BIT
#define LONG "%08lx "
#define FOURLONG "%08lx %08lx %08lx %08lx\n"
static int kstack_depth_to_print = 12;
#else /* CONFIG_64BIT */
#define LONG "%016lx "
#define FOURLONG "%016lx %016lx %016lx %016lx\n"
static int kstack_depth_to_print = 20;
#endif /* CONFIG_64BIT */
/*
* For show_trace we have tree different stack to consider:
* - the panic stack which is used if the kernel stack has overflown
* - the asynchronous interrupt stack (cpu related)
* - the synchronous kernel stack (process related)
* The stack trace can start at any of the three stack and can potentially
* touch all of them. The order is: panic stack, async stack, sync stack.
*/
static unsigned long
__show_trace(unsigned long sp, unsigned long low, unsigned long high)
{
struct stack_frame *sf;
struct pt_regs *regs;
while (1) {
sp = sp & PSW_ADDR_INSN;
if (sp < low || sp > high - sizeof(*sf))
return sp;
sf = (struct stack_frame *) sp;
printk("([<%016lx>] ", sf->gprs[8] & PSW_ADDR_INSN);
print_symbol("%s)\n", sf->gprs[8] & PSW_ADDR_INSN);
/* Follow the backchain. */
while (1) {
low = sp;
sp = sf->back_chain & PSW_ADDR_INSN;
if (!sp)
break;
if (sp <= low || sp > high - sizeof(*sf))
return sp;
sf = (struct stack_frame *) sp;
printk(" [<%016lx>] ", sf->gprs[8] & PSW_ADDR_INSN);
print_symbol("%s\n", sf->gprs[8] & PSW_ADDR_INSN);
}
/* Zero backchain detected, check for interrupt frame. */
sp = (unsigned long) (sf + 1);
if (sp <= low || sp > high - sizeof(*regs))
return sp;
regs = (struct pt_regs *) sp;
printk(" [<%016lx>] ", regs->psw.addr & PSW_ADDR_INSN);
print_symbol("%s\n", regs->psw.addr & PSW_ADDR_INSN);
low = sp;
sp = regs->gprs[15];
}
}
static void show_trace(struct task_struct *task, unsigned long *stack)
{
register unsigned long __r15 asm ("15");
unsigned long sp;
sp = (unsigned long) stack;
if (!sp)
sp = task ? task->thread.ksp : __r15;
printk("Call Trace:\n");
#ifdef CONFIG_CHECK_STACK
sp = __show_trace(sp, S390_lowcore.panic_stack - 4096,
S390_lowcore.panic_stack);
#endif
sp = __show_trace(sp, S390_lowcore.async_stack - ASYNC_SIZE,
S390_lowcore.async_stack);
if (task)
__show_trace(sp, (unsigned long) task_stack_page(task),
(unsigned long) task_stack_page(task) + THREAD_SIZE);
else
__show_trace(sp, S390_lowcore.thread_info,
S390_lowcore.thread_info + THREAD_SIZE);
if (!task)
task = current;
debug_show_held_locks(task);
}
void show_stack(struct task_struct *task, unsigned long *sp)
{
register unsigned long * __r15 asm ("15");
unsigned long *stack;
int i;
if (!sp)
stack = task ? (unsigned long *) task->thread.ksp : __r15;
else
stack = sp;
for (i = 0; i < kstack_depth_to_print; i++) {
if (((addr_t) stack & (THREAD_SIZE-1)) == 0)
break;
if (i && ((i * sizeof (long) % 32) == 0))
printk("\n ");
printk(LONG, *stack++);
}
printk("\n");
show_trace(task, sp);
}
static void show_last_breaking_event(struct pt_regs *regs)
{
#ifdef CONFIG_64BIT
printk("Last Breaking-Event-Address:\n");
printk(" [<%016lx>] ", regs->args[0] & PSW_ADDR_INSN);
print_symbol("%s\n", regs->args[0] & PSW_ADDR_INSN);
#endif
}
/*
* The architecture-independent dump_stack generator
*/
void dump_stack(void)
{
printk("CPU: %d %s %s %.*s\n",
task_thread_info(current)->cpu, print_tainted(),
init_utsname()->release,
(int)strcspn(init_utsname()->version, " "),
init_utsname()->version);
printk("Process %s (pid: %d, task: %p, ksp: %p)\n",
current->comm, current->pid, current,
(void *) current->thread.ksp);
show_stack(NULL, NULL);
}
EXPORT_SYMBOL(dump_stack);
static inline int mask_bits(struct pt_regs *regs, unsigned long bits)
{
return (regs->psw.mask & bits) / ((~bits + 1) & bits);
}
void show_registers(struct pt_regs *regs)
{
char *mode;
mode = (regs->psw.mask & PSW_MASK_PSTATE) ? "User" : "Krnl";
printk("%s PSW : %p %p",
mode, (void *) regs->psw.mask,
(void *) regs->psw.addr);
print_symbol(" (%s)\n", regs->psw.addr & PSW_ADDR_INSN);
printk(" R:%x T:%x IO:%x EX:%x Key:%x M:%x W:%x "
"P:%x AS:%x CC:%x PM:%x", mask_bits(regs, PSW_MASK_PER),
mask_bits(regs, PSW_MASK_DAT), mask_bits(regs, PSW_MASK_IO),
mask_bits(regs, PSW_MASK_EXT), mask_bits(regs, PSW_MASK_KEY),
mask_bits(regs, PSW_MASK_MCHECK), mask_bits(regs, PSW_MASK_WAIT),
mask_bits(regs, PSW_MASK_PSTATE), mask_bits(regs, PSW_MASK_ASC),
mask_bits(regs, PSW_MASK_CC), mask_bits(regs, PSW_MASK_PM));
#ifdef CONFIG_64BIT
printk(" EA:%x", mask_bits(regs, PSW_MASK_EA | PSW_MASK_BA));
#endif
printk("\n%s GPRS: " FOURLONG, mode,
regs->gprs[0], regs->gprs[1], regs->gprs[2], regs->gprs[3]);
printk(" " FOURLONG,
regs->gprs[4], regs->gprs[5], regs->gprs[6], regs->gprs[7]);
printk(" " FOURLONG,
regs->gprs[8], regs->gprs[9], regs->gprs[10], regs->gprs[11]);
printk(" " FOURLONG,
regs->gprs[12], regs->gprs[13], regs->gprs[14], regs->gprs[15]);
show_code(regs);
}
void show_regs(struct pt_regs *regs)
{
print_modules();
printk("CPU: %d %s %s %.*s\n",
task_thread_info(current)->cpu, print_tainted(),
init_utsname()->release,
(int)strcspn(init_utsname()->version, " "),
init_utsname()->version);
printk("Process %s (pid: %d, task: %p, ksp: %p)\n",
current->comm, current->pid, current,
(void *) current->thread.ksp);
show_registers(regs);
/* Show stack backtrace if pt_regs is from kernel mode */
if (!(regs->psw.mask & PSW_MASK_PSTATE))
show_trace(NULL, (unsigned long *) regs->gprs[15]);
show_last_breaking_event(regs);
}
static DEFINE_SPINLOCK(die_lock);
void die(struct pt_regs *regs, const char *str)
{
static int die_counter;
oops_enter();
debug_stop_all();
console_verbose();
spin_lock_irq(&die_lock);
bust_spinlocks(1);
printk("%s: %04x [#%d] ", str, regs->int_code & 0xffff, ++die_counter);
#ifdef CONFIG_PREEMPT
printk("PREEMPT ");
#endif
#ifdef CONFIG_SMP
printk("SMP ");
#endif
#ifdef CONFIG_DEBUG_PAGEALLOC
printk("DEBUG_PAGEALLOC");
#endif
printk("\n");
notify_die(DIE_OOPS, str, regs, 0, regs->int_code & 0xffff, SIGSEGV);
show_regs(regs);
bust_spinlocks(0);
add_taint(TAINT_DIE);
spin_unlock_irq(&die_lock);
if (in_interrupt())
panic("Fatal exception in interrupt");
if (panic_on_oops)
panic("Fatal exception: panic_on_oops");
oops_exit();
do_exit(SIGSEGV);
}
static inline void report_user_fault(struct pt_regs *regs, int signr)
{
if ((task_pid_nr(current) > 1) && !show_unhandled_signals)
return;
if (!unhandled_signal(current, signr))
return;
if (!printk_ratelimit())
return;
printk("User process fault: interruption code 0x%X ", regs->int_code);
print_vma_addr("in ", regs->psw.addr & PSW_ADDR_INSN);
printk("\n");
show_regs(regs);
}
int is_valid_bugaddr(unsigned long addr)
{
return 1;
}
static inline void __user *get_psw_address(struct pt_regs *regs)
{
return (void __user *)
((regs->psw.addr - (regs->int_code >> 16)) & PSW_ADDR_INSN);
}
static void __kprobes do_trap(struct pt_regs *regs,
int si_signo, int si_code, char *str)
{
siginfo_t info;
if (notify_die(DIE_TRAP, str, regs, 0,
regs->int_code, si_signo) == NOTIFY_STOP)
return;
if (regs->psw.mask & PSW_MASK_PSTATE) {
info.si_signo = si_signo;
info.si_errno = 0;
info.si_code = si_code;
info.si_addr = get_psw_address(regs);
force_sig_info(si_signo, &info, current);
report_user_fault(regs, si_signo);
} else {
const struct exception_table_entry *fixup;
fixup = search_exception_tables(regs->psw.addr & PSW_ADDR_INSN);
if (fixup)
regs->psw.addr = fixup->fixup | PSW_ADDR_AMODE;
else {
enum bug_trap_type btt;
btt = report_bug(regs->psw.addr & PSW_ADDR_INSN, regs);
if (btt == BUG_TRAP_TYPE_WARN)
return;
die(regs, str);
}
}
}
void __kprobes do_per_trap(struct pt_regs *regs)
{
siginfo_t info;
if (notify_die(DIE_SSTEP, "sstep", regs, 0, 0, SIGTRAP) == NOTIFY_STOP)
return;
if (!current->ptrace)
return;
info.si_signo = SIGTRAP;
info.si_errno = 0;
info.si_code = TRAP_HWBKPT;
info.si_addr =
(void __force __user *) current->thread.per_event.address;
force_sig_info(SIGTRAP, &info, current);
}
static void default_trap_handler(struct pt_regs *regs)
{
if (regs->psw.mask & PSW_MASK_PSTATE) {
report_user_fault(regs, SIGSEGV);
do_exit(SIGSEGV);
} else
die(regs, "Unknown program exception");
}
#define DO_ERROR_INFO(name, signr, sicode, str) \
static void name(struct pt_regs *regs) \
{ \
do_trap(regs, signr, sicode, str); \
}
DO_ERROR_INFO(addressing_exception, SIGILL, ILL_ILLADR,
"addressing exception")
DO_ERROR_INFO(execute_exception, SIGILL, ILL_ILLOPN,
"execute exception")
DO_ERROR_INFO(divide_exception, SIGFPE, FPE_INTDIV,
"fixpoint divide exception")
DO_ERROR_INFO(overflow_exception, SIGFPE, FPE_INTOVF,
"fixpoint overflow exception")
DO_ERROR_INFO(hfp_overflow_exception, SIGFPE, FPE_FLTOVF,
"HFP overflow exception")
DO_ERROR_INFO(hfp_underflow_exception, SIGFPE, FPE_FLTUND,
"HFP underflow exception")
DO_ERROR_INFO(hfp_significance_exception, SIGFPE, FPE_FLTRES,
"HFP significance exception")
DO_ERROR_INFO(hfp_divide_exception, SIGFPE, FPE_FLTDIV,
"HFP divide exception")
DO_ERROR_INFO(hfp_sqrt_exception, SIGFPE, FPE_FLTINV,
"HFP square root exception")
DO_ERROR_INFO(operand_exception, SIGILL, ILL_ILLOPN,
"operand exception")
DO_ERROR_INFO(privileged_op, SIGILL, ILL_PRVOPC,
"privileged operation")
DO_ERROR_INFO(special_op_exception, SIGILL, ILL_ILLOPN,
"special operation exception")
DO_ERROR_INFO(translation_exception, SIGILL, ILL_ILLOPN,
"translation exception")
static inline void do_fp_trap(struct pt_regs *regs, int fpc)
{
int si_code = 0;
/* FPC[2] is Data Exception Code */
if ((fpc & 0x00000300) == 0) {
/* bits 6 and 7 of DXC are 0 iff IEEE exception */
if (fpc & 0x8000) /* invalid fp operation */
si_code = FPE_FLTINV;
else if (fpc & 0x4000) /* div by 0 */
si_code = FPE_FLTDIV;
else if (fpc & 0x2000) /* overflow */
si_code = FPE_FLTOVF;
else if (fpc & 0x1000) /* underflow */
si_code = FPE_FLTUND;
else if (fpc & 0x0800) /* inexact */
si_code = FPE_FLTRES;
}
do_trap(regs, SIGFPE, si_code, "floating point exception");
}
static void __kprobes illegal_op(struct pt_regs *regs)
{
siginfo_t info;
__u8 opcode[6];
__u16 __user *location;
int signal = 0;
location = get_psw_address(regs);
if (regs->psw.mask & PSW_MASK_PSTATE) {
if (get_user(*((__u16 *) opcode), (__u16 __user *) location))
return;
if (*((__u16 *) opcode) == S390_BREAKPOINT_U16) {
if (current->ptrace) {
info.si_signo = SIGTRAP;
info.si_errno = 0;
info.si_code = TRAP_BRKPT;
info.si_addr = location;
force_sig_info(SIGTRAP, &info, current);
} else
signal = SIGILL;
#ifdef CONFIG_MATHEMU
} else if (opcode[0] == 0xb3) {
if (get_user(*((__u16 *) (opcode+2)), location+1))
return;
signal = math_emu_b3(opcode, regs);
} else if (opcode[0] == 0xed) {
if (get_user(*((__u32 *) (opcode+2)),
(__u32 __user *)(location+1)))
return;
signal = math_emu_ed(opcode, regs);
} else if (*((__u16 *) opcode) == 0xb299) {
if (get_user(*((__u16 *) (opcode+2)), location+1))
return;
signal = math_emu_srnm(opcode, regs);
} else if (*((__u16 *) opcode) == 0xb29c) {
if (get_user(*((__u16 *) (opcode+2)), location+1))
return;
signal = math_emu_stfpc(opcode, regs);
} else if (*((__u16 *) opcode) == 0xb29d) {
if (get_user(*((__u16 *) (opcode+2)), location+1))
return;
signal = math_emu_lfpc(opcode, regs);
#endif
} else
signal = SIGILL;
} else {
/*
* If we get an illegal op in kernel mode, send it through the
* kprobes notifier. If kprobes doesn't pick it up, SIGILL
*/
if (notify_die(DIE_BPT, "bpt", regs, 0,
3, SIGTRAP) != NOTIFY_STOP)
signal = SIGILL;
}
#ifdef CONFIG_MATHEMU
if (signal == SIGFPE)
do_fp_trap(regs, current->thread.fp_regs.fpc);
else if (signal == SIGSEGV)
do_trap(regs, signal, SEGV_MAPERR, "user address fault");
else
#endif
if (signal)
do_trap(regs, signal, ILL_ILLOPC, "illegal operation");
}
#ifdef CONFIG_MATHEMU
void specification_exception(struct pt_regs *regs)
{
__u8 opcode[6];
__u16 __user *location = NULL;
int signal = 0;
location = (__u16 __user *) get_psw_address(regs);
if (regs->psw.mask & PSW_MASK_PSTATE) {
get_user(*((__u16 *) opcode), location);
switch (opcode[0]) {
case 0x28: /* LDR Rx,Ry */
signal = math_emu_ldr(opcode);
break;
case 0x38: /* LER Rx,Ry */
signal = math_emu_ler(opcode);
break;
case 0x60: /* STD R,D(X,B) */
get_user(*((__u16 *) (opcode+2)), location+1);
signal = math_emu_std(opcode, regs);
break;
case 0x68: /* LD R,D(X,B) */
get_user(*((__u16 *) (opcode+2)), location+1);
signal = math_emu_ld(opcode, regs);
break;
case 0x70: /* STE R,D(X,B) */
get_user(*((__u16 *) (opcode+2)), location+1);
signal = math_emu_ste(opcode, regs);
break;
case 0x78: /* LE R,D(X,B) */
get_user(*((__u16 *) (opcode+2)), location+1);
signal = math_emu_le(opcode, regs);
break;
default:
signal = SIGILL;
break;
}
} else
signal = SIGILL;
if (signal == SIGFPE)
do_fp_trap(regs, current->thread.fp_regs.fpc);
else if (signal)
do_trap(regs, signal, ILL_ILLOPN, "specification exception");
}
#else
DO_ERROR_INFO(specification_exception, SIGILL, ILL_ILLOPN,
"specification exception");
#endif
static void data_exception(struct pt_regs *regs)
{
__u16 __user *location;
int signal = 0;
location = get_psw_address(regs);
if (MACHINE_HAS_IEEE)
asm volatile("stfpc %0" : "=m" (current->thread.fp_regs.fpc));
#ifdef CONFIG_MATHEMU
else if (regs->psw.mask & PSW_MASK_PSTATE) {
__u8 opcode[6];
get_user(*((__u16 *) opcode), location);
switch (opcode[0]) {
case 0x28: /* LDR Rx,Ry */
signal = math_emu_ldr(opcode);
break;
case 0x38: /* LER Rx,Ry */
signal = math_emu_ler(opcode);
break;
case 0x60: /* STD R,D(X,B) */
get_user(*((__u16 *) (opcode+2)), location+1);
signal = math_emu_std(opcode, regs);
break;
case 0x68: /* LD R,D(X,B) */
get_user(*((__u16 *) (opcode+2)), location+1);
signal = math_emu_ld(opcode, regs);
break;
case 0x70: /* STE R,D(X,B) */
get_user(*((__u16 *) (opcode+2)), location+1);
signal = math_emu_ste(opcode, regs);
break;
case 0x78: /* LE R,D(X,B) */
get_user(*((__u16 *) (opcode+2)), location+1);
signal = math_emu_le(opcode, regs);
break;
case 0xb3:
get_user(*((__u16 *) (opcode+2)), location+1);
signal = math_emu_b3(opcode, regs);
break;
case 0xed:
get_user(*((__u32 *) (opcode+2)),
(__u32 __user *)(location+1));
signal = math_emu_ed(opcode, regs);
break;
case 0xb2:
if (opcode[1] == 0x99) {
get_user(*((__u16 *) (opcode+2)), location+1);
signal = math_emu_srnm(opcode, regs);
} else if (opcode[1] == 0x9c) {
get_user(*((__u16 *) (opcode+2)), location+1);
signal = math_emu_stfpc(opcode, regs);
} else if (opcode[1] == 0x9d) {
get_user(*((__u16 *) (opcode+2)), location+1);
signal = math_emu_lfpc(opcode, regs);
} else
signal = SIGILL;
break;
default:
signal = SIGILL;
break;
}
}
#endif
if (current->thread.fp_regs.fpc & FPC_DXC_MASK)
signal = SIGFPE;
else
signal = SIGILL;
if (signal == SIGFPE)
do_fp_trap(regs, current->thread.fp_regs.fpc);
else if (signal)
do_trap(regs, signal, ILL_ILLOPN, "data exception");
}
static void space_switch_exception(struct pt_regs *regs)
{
/* Set user psw back to home space mode. */
if (regs->psw.mask & PSW_MASK_PSTATE)
regs->psw.mask |= PSW_ASC_HOME;
/* Send SIGILL. */
do_trap(regs, SIGILL, ILL_PRVOPC, "space switch event");
}
void __kprobes kernel_stack_overflow(struct pt_regs * regs)
{
bust_spinlocks(1);
printk("Kernel stack overflow.\n");
show_regs(regs);
bust_spinlocks(0);
panic("Corrupt kernel stack, can't continue.");
}
/* init is done in lowcore.S and head.S */
void __init trap_init(void)
{
int i;
for (i = 0; i < 128; i++)
pgm_check_table[i] = &default_trap_handler;
pgm_check_table[1] = &illegal_op;
pgm_check_table[2] = &privileged_op;
pgm_check_table[3] = &execute_exception;
pgm_check_table[4] = &do_protection_exception;
pgm_check_table[5] = &addressing_exception;
pgm_check_table[6] = &specification_exception;
pgm_check_table[7] = &data_exception;
pgm_check_table[8] = &overflow_exception;
pgm_check_table[9] = &divide_exception;
pgm_check_table[0x0A] = &overflow_exception;
pgm_check_table[0x0B] = &divide_exception;
pgm_check_table[0x0C] = &hfp_overflow_exception;
pgm_check_table[0x0D] = &hfp_underflow_exception;
pgm_check_table[0x0E] = &hfp_significance_exception;
pgm_check_table[0x0F] = &hfp_divide_exception;
pgm_check_table[0x10] = &do_dat_exception;
pgm_check_table[0x11] = &do_dat_exception;
pgm_check_table[0x12] = &translation_exception;
pgm_check_table[0x13] = &special_op_exception;
#ifdef CONFIG_64BIT
pgm_check_table[0x38] = &do_asce_exception;
pgm_check_table[0x39] = &do_dat_exception;
pgm_check_table[0x3A] = &do_dat_exception;
pgm_check_table[0x3B] = &do_dat_exception;
#endif /* CONFIG_64BIT */
pgm_check_table[0x15] = &operand_exception;
pgm_check_table[0x1C] = &space_switch_exception;
pgm_check_table[0x1D] = &hfp_sqrt_exception;
/* Enable machine checks early. */
local_mcck_enable();
}
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