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linux/arch/openrisc/kernel/traps.c
Linus Torvalds ab486bc9a5 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk 
Pull printk updates from Petr Mladek:

 - Add a console_msg_format command line option:

     The value "default" keeps the old "[time stamp] text\n" format. The
     value "syslog" allows to see the syslog-like "<log
     level>[timestamp] text" format.

     This feature was requested by people doing regression tests, for
     example, 0day robot. They want to have both filtered and full logs
     at hands.

 - Reduce the risk of softlockup:

     Pass the console owner in a busy loop.

     This is a new approach to the old problem. It was first proposed by
     Steven Rostedt on Kernel Summit 2017. It marks a context in which
     the console_lock owner calls console drivers and could not sleep.
     On the other side, printk() callers could detect this state and use
     a busy wait instead of a simple console_trylock(). Finally, the
     console_lock owner checks if there is a busy waiter at the end of
     the special context and eventually passes the console_lock to the
     waiter.

     The hand-off works surprisingly well and helps in many situations.
     Well, there is still a possibility of the softlockup, for example,
     when the flood of messages stops and the last owner still has too
     much to flush.

     There is increasing number of people having problems with
     printk-related softlockups. We might eventually need to get better
     solution. Anyway, this looks like a good start and promising
     direction.

 - Do not allow to schedule in console_unlock() called from printk():

     This reverts an older controversial commit. The reschedule helped
     to avoid softlockups. But it also slowed down the console output.
     This patch is obsoleted by the new console waiter logic described
     above. In fact, the reschedule made the hand-off less effective.

 - Deprecate "%pf" and "%pF" format specifier:

     It was needed on ia64, ppc64 and parisc64 to dereference function
     descriptors and show the real function address. It is done
     transparently by "%ps" and "pS" format specifier now.

     Sergey Senozhatsky found that all the function descriptors were in
     a special elf section and could be easily detected.

 - Remove printk_symbol() API:

     It has been obsoleted by "%pS" format specifier, and this change
     helped to remove few continuous lines and a less intuitive old API.

 - Remove redundant memsets:

     Sergey removed unnecessary memset when processing printk.devkmsg
     command line option.

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk: (27 commits)
  printk: drop redundant devkmsg_log_str memsets
  printk: Never set console_may_schedule in console_trylock()
  printk: Hide console waiter logic into helpers
  printk: Add console owner and waiter logic to load balance console writes
  kallsyms: remove print_symbol() function
  checkpatch: add pF/pf deprecation warning
  symbol lookup: introduce dereference_symbol_descriptor()
  parisc64: Add .opd based function descriptor dereference
  powerpc64: Add .opd based function descriptor dereference
  ia64: Add .opd based function descriptor dereference
  sections: split dereference_function_descriptor()
  openrisc: Fix conflicting types for _exext and _stext
  lib: do not use print_symbol()
  irq debug: do not use print_symbol()
  sysfs: do not use print_symbol()
  drivers: do not use print_symbol()
  x86: do not use print_symbol()
  unicore32: do not use print_symbol()
  sh: do not use print_symbol()
  mn10300: do not use print_symbol()
  ...
2018-02-01 13:36:15 -08:00

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/*
* OpenRISC traps.c
*
* Linux architectural port borrowing liberally from similar works of
* others. All original copyrights apply as per the original source
* declaration.
*
* Modifications for the OpenRISC architecture:
* Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
* Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
* Here we handle the break vectors not used by the system call
* mechanism, as well as some general stack/register dumping
* things.
*
*/
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/sched/debug.h>
#include <linux/sched/task_stack.h>
#include <linux/kernel.h>
#include <linux/extable.h>
#include <linux/kmod.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/ptrace.h>
#include <linux/timer.h>
#include <linux/mm.h>
#include <linux/kallsyms.h>
#include <linux/uaccess.h>
#include <asm/segment.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/unwinder.h>
#include <asm/sections.h>
int kstack_depth_to_print = 0x180;
int lwa_flag;
unsigned long __user *lwa_addr;
void print_trace(void *data, unsigned long addr, int reliable)
{
pr_emerg("[<%p>] %s%pS\n", (void *) addr, reliable ? "" : "? ",
(void *) addr);
}
/* displays a short stack trace */
void show_stack(struct task_struct *task, unsigned long *esp)
{
if (esp == NULL)
esp = (unsigned long *)&esp;
pr_emerg("Call trace:\n");
unwind_stack(NULL, esp, print_trace);
}
void show_trace_task(struct task_struct *tsk)
{
/*
* TODO: SysRq-T trace dump...
*/
}
void show_registers(struct pt_regs *regs)
{
int i;
int in_kernel = 1;
unsigned long esp;
esp = (unsigned long)(regs->sp);
if (user_mode(regs))
in_kernel = 0;
printk("CPU #: %d\n"
" PC: %08lx SR: %08lx SP: %08lx\n",
smp_processor_id(), regs->pc, regs->sr, regs->sp);
printk("GPR00: %08lx GPR01: %08lx GPR02: %08lx GPR03: %08lx\n",
0L, regs->gpr[1], regs->gpr[2], regs->gpr[3]);
printk("GPR04: %08lx GPR05: %08lx GPR06: %08lx GPR07: %08lx\n",
regs->gpr[4], regs->gpr[5], regs->gpr[6], regs->gpr[7]);
printk("GPR08: %08lx GPR09: %08lx GPR10: %08lx GPR11: %08lx\n",
regs->gpr[8], regs->gpr[9], regs->gpr[10], regs->gpr[11]);
printk("GPR12: %08lx GPR13: %08lx GPR14: %08lx GPR15: %08lx\n",
regs->gpr[12], regs->gpr[13], regs->gpr[14], regs->gpr[15]);
printk("GPR16: %08lx GPR17: %08lx GPR18: %08lx GPR19: %08lx\n",
regs->gpr[16], regs->gpr[17], regs->gpr[18], regs->gpr[19]);
printk("GPR20: %08lx GPR21: %08lx GPR22: %08lx GPR23: %08lx\n",
regs->gpr[20], regs->gpr[21], regs->gpr[22], regs->gpr[23]);
printk("GPR24: %08lx GPR25: %08lx GPR26: %08lx GPR27: %08lx\n",
regs->gpr[24], regs->gpr[25], regs->gpr[26], regs->gpr[27]);
printk("GPR28: %08lx GPR29: %08lx GPR30: %08lx GPR31: %08lx\n",
regs->gpr[28], regs->gpr[29], regs->gpr[30], regs->gpr[31]);
printk(" RES: %08lx oGPR11: %08lx\n",
regs->gpr[11], regs->orig_gpr11);
printk("Process %s (pid: %d, stackpage=%08lx)\n",
current->comm, current->pid, (unsigned long)current);
/*
* When in-kernel, we also print out the stack and code at the
* time of the fault..
*/
if (in_kernel) {
printk("\nStack: ");
show_stack(NULL, (unsigned long *)esp);
printk("\nCode: ");
if (regs->pc < PAGE_OFFSET)
goto bad;
for (i = -24; i < 24; i++) {
unsigned char c;
if (__get_user(c, &((unsigned char *)regs->pc)[i])) {
bad:
printk(" Bad PC value.");
break;
}
if (i == 0)
printk("(%02x) ", c);
else
printk("%02x ", c);
}
}
printk("\n");
}
void nommu_dump_state(struct pt_regs *regs,
unsigned long ea, unsigned long vector)
{
int i;
unsigned long addr, stack = regs->sp;
printk("\n\r[nommu_dump_state] :: ea %lx, vector %lx\n\r", ea, vector);
printk("CPU #: %d\n"
" PC: %08lx SR: %08lx SP: %08lx\n",
0, regs->pc, regs->sr, regs->sp);
printk("GPR00: %08lx GPR01: %08lx GPR02: %08lx GPR03: %08lx\n",
0L, regs->gpr[1], regs->gpr[2], regs->gpr[3]);
printk("GPR04: %08lx GPR05: %08lx GPR06: %08lx GPR07: %08lx\n",
regs->gpr[4], regs->gpr[5], regs->gpr[6], regs->gpr[7]);
printk("GPR08: %08lx GPR09: %08lx GPR10: %08lx GPR11: %08lx\n",
regs->gpr[8], regs->gpr[9], regs->gpr[10], regs->gpr[11]);
printk("GPR12: %08lx GPR13: %08lx GPR14: %08lx GPR15: %08lx\n",
regs->gpr[12], regs->gpr[13], regs->gpr[14], regs->gpr[15]);
printk("GPR16: %08lx GPR17: %08lx GPR18: %08lx GPR19: %08lx\n",
regs->gpr[16], regs->gpr[17], regs->gpr[18], regs->gpr[19]);
printk("GPR20: %08lx GPR21: %08lx GPR22: %08lx GPR23: %08lx\n",
regs->gpr[20], regs->gpr[21], regs->gpr[22], regs->gpr[23]);
printk("GPR24: %08lx GPR25: %08lx GPR26: %08lx GPR27: %08lx\n",
regs->gpr[24], regs->gpr[25], regs->gpr[26], regs->gpr[27]);
printk("GPR28: %08lx GPR29: %08lx GPR30: %08lx GPR31: %08lx\n",
regs->gpr[28], regs->gpr[29], regs->gpr[30], regs->gpr[31]);
printk(" RES: %08lx oGPR11: %08lx\n",
regs->gpr[11], regs->orig_gpr11);
printk("Process %s (pid: %d, stackpage=%08lx)\n",
((struct task_struct *)(__pa(current)))->comm,
((struct task_struct *)(__pa(current)))->pid,
(unsigned long)current);
printk("\nStack: ");
printk("Stack dump [0x%08lx]:\n", (unsigned long)stack);
for (i = 0; i < kstack_depth_to_print; i++) {
if (((long)stack & (THREAD_SIZE - 1)) == 0)
break;
stack++;
printk("%lx :: sp + %02d: 0x%08lx\n", stack, i * 4,
*((unsigned long *)(__pa(stack))));
}
printk("\n");
printk("Call Trace: ");
i = 1;
while (((long)stack & (THREAD_SIZE - 1)) != 0) {
addr = *((unsigned long *)__pa(stack));
stack++;
if (kernel_text_address(addr)) {
if (i && ((i % 6) == 0))
printk("\n ");
printk(" [<%08lx>]", addr);
i++;
}
}
printk("\n");
printk("\nCode: ");
for (i = -24; i < 24; i++) {
unsigned char c;
c = ((unsigned char *)(__pa(regs->pc)))[i];
if (i == 0)
printk("(%02x) ", c);
else
printk("%02x ", c);
}
printk("\n");
}
/* This is normally the 'Oops' routine */
void die(const char *str, struct pt_regs *regs, long err)
{
console_verbose();
printk("\n%s#: %04lx\n", str, err & 0xffff);
show_registers(regs);
#ifdef CONFIG_JUMP_UPON_UNHANDLED_EXCEPTION
printk("\n\nUNHANDLED_EXCEPTION: entering infinite loop\n");
/* shut down interrupts */
local_irq_disable();
__asm__ __volatile__("l.nop 1");
do {} while (1);
#endif
do_exit(SIGSEGV);
}
/* This is normally the 'Oops' routine */
void die_if_kernel(const char *str, struct pt_regs *regs, long err)
{
if (user_mode(regs))
return;
die(str, regs, err);
}
void unhandled_exception(struct pt_regs *regs, int ea, int vector)
{
printk("Unable to handle exception at EA =0x%x, vector 0x%x",
ea, vector);
die("Oops", regs, 9);
}
void __init trap_init(void)
{
/* Nothing needs to be done */
}
asmlinkage void do_trap(struct pt_regs *regs, unsigned long address)
{
siginfo_t info;
memset(&info, 0, sizeof(info));
info.si_signo = SIGTRAP;
info.si_code = TRAP_TRACE;
info.si_addr = (void *)address;
force_sig_info(SIGTRAP, &info, current);
regs->pc += 4;
}
asmlinkage void do_unaligned_access(struct pt_regs *regs, unsigned long address)
{
siginfo_t info;
if (user_mode(regs)) {
/* Send a SIGBUS */
info.si_signo = SIGBUS;
info.si_errno = 0;
info.si_code = BUS_ADRALN;
info.si_addr = (void __user *)address;
force_sig_info(SIGBUS, &info, current);
} else {
printk("KERNEL: Unaligned Access 0x%.8lx\n", address);
show_registers(regs);
die("Die:", regs, address);
}
}
asmlinkage void do_bus_fault(struct pt_regs *regs, unsigned long address)
{
siginfo_t info;
if (user_mode(regs)) {
/* Send a SIGBUS */
info.si_signo = SIGBUS;
info.si_errno = 0;
info.si_code = BUS_ADRERR;
info.si_addr = (void *)address;
force_sig_info(SIGBUS, &info, current);
} else { /* Kernel mode */
printk("KERNEL: Bus error (SIGBUS) 0x%.8lx\n", address);
show_registers(regs);
die("Die:", regs, address);
}
}
static inline int in_delay_slot(struct pt_regs *regs)
{
#ifdef CONFIG_OPENRISC_NO_SPR_SR_DSX
/* No delay slot flag, do the old way */
unsigned int op, insn;
insn = *((unsigned int *)regs->pc);
op = insn >> 26;
switch (op) {
case 0x00: /* l.j */
case 0x01: /* l.jal */
case 0x03: /* l.bnf */
case 0x04: /* l.bf */
case 0x11: /* l.jr */
case 0x12: /* l.jalr */
return 1;
default:
return 0;
}
#else
return regs->sr & SPR_SR_DSX;
#endif
}
static inline void adjust_pc(struct pt_regs *regs, unsigned long address)
{
int displacement;
unsigned int rb, op, jmp;
if (unlikely(in_delay_slot(regs))) {
/* In delay slot, instruction at pc is a branch, simulate it */
jmp = *((unsigned int *)regs->pc);
displacement = sign_extend32(((jmp) & 0x3ffffff) << 2, 27);
rb = (jmp & 0x0000ffff) >> 11;
op = jmp >> 26;
switch (op) {
case 0x00: /* l.j */
regs->pc += displacement;
return;
case 0x01: /* l.jal */
regs->pc += displacement;
regs->gpr[9] = regs->pc + 8;
return;
case 0x03: /* l.bnf */
if (regs->sr & SPR_SR_F)
regs->pc += 8;
else
regs->pc += displacement;
return;
case 0x04: /* l.bf */
if (regs->sr & SPR_SR_F)
regs->pc += displacement;
else
regs->pc += 8;
return;
case 0x11: /* l.jr */
regs->pc = regs->gpr[rb];
return;
case 0x12: /* l.jalr */
regs->pc = regs->gpr[rb];
regs->gpr[9] = regs->pc + 8;
return;
default:
break;
}
} else {
regs->pc += 4;
}
}
static inline void simulate_lwa(struct pt_regs *regs, unsigned long address,
unsigned int insn)
{
unsigned int ra, rd;
unsigned long value;
unsigned long orig_pc;
long imm;
const struct exception_table_entry *entry;
orig_pc = regs->pc;
adjust_pc(regs, address);
ra = (insn >> 16) & 0x1f;
rd = (insn >> 21) & 0x1f;
imm = (short)insn;
lwa_addr = (unsigned long __user *)(regs->gpr[ra] + imm);
if ((unsigned long)lwa_addr & 0x3) {
do_unaligned_access(regs, address);
return;
}
if (get_user(value, lwa_addr)) {
if (user_mode(regs)) {
force_sig(SIGSEGV, current);
return;
}
if ((entry = search_exception_tables(orig_pc))) {
regs->pc = entry->fixup;
return;
}
/* kernel access in kernel space, load it directly */
value = *((unsigned long *)lwa_addr);
}
lwa_flag = 1;
regs->gpr[rd] = value;
}
static inline void simulate_swa(struct pt_regs *regs, unsigned long address,
unsigned int insn)
{
unsigned long __user *vaddr;
unsigned long orig_pc;
unsigned int ra, rb;
long imm;
const struct exception_table_entry *entry;
orig_pc = regs->pc;
adjust_pc(regs, address);
ra = (insn >> 16) & 0x1f;
rb = (insn >> 11) & 0x1f;
imm = (short)(((insn & 0x2200000) >> 10) | (insn & 0x7ff));
vaddr = (unsigned long __user *)(regs->gpr[ra] + imm);
if (!lwa_flag || vaddr != lwa_addr) {
regs->sr &= ~SPR_SR_F;
return;
}
if ((unsigned long)vaddr & 0x3) {
do_unaligned_access(regs, address);
return;
}
if (put_user(regs->gpr[rb], vaddr)) {
if (user_mode(regs)) {
force_sig(SIGSEGV, current);
return;
}
if ((entry = search_exception_tables(orig_pc))) {
regs->pc = entry->fixup;
return;
}
/* kernel access in kernel space, store it directly */
*((unsigned long *)vaddr) = regs->gpr[rb];
}
lwa_flag = 0;
regs->sr |= SPR_SR_F;
}
#define INSN_LWA 0x1b
#define INSN_SWA 0x33
asmlinkage void do_illegal_instruction(struct pt_regs *regs,
unsigned long address)
{
siginfo_t info;
unsigned int op;
unsigned int insn = *((unsigned int *)address);
op = insn >> 26;
switch (op) {
case INSN_LWA:
simulate_lwa(regs, address, insn);
return;
case INSN_SWA:
simulate_swa(regs, address, insn);
return;
default:
break;
}
if (user_mode(regs)) {
/* Send a SIGILL */
info.si_signo = SIGILL;
info.si_errno = 0;
info.si_code = ILL_ILLOPC;
info.si_addr = (void *)address;
force_sig_info(SIGBUS, &info, current);
} else { /* Kernel mode */
printk("KERNEL: Illegal instruction (SIGILL) 0x%.8lx\n",
address);
show_registers(regs);
die("Die:", regs, address);
}
}
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