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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* 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>
*
* 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/bug.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/unwinder.h>
#include <asm/sections.h>
int lwa_flag;
static unsigned long __user *lwa_addr;
asmlinkage void unhandled_exception(struct pt_regs *regs, int ea, int vector);
asmlinkage void do_trap(struct pt_regs *regs, unsigned long address);
asmlinkage void do_fpe_trap(struct pt_regs *regs, unsigned long address);
asmlinkage void do_unaligned_access(struct pt_regs *regs, unsigned long address);
asmlinkage void do_bus_fault(struct pt_regs *regs, unsigned long address);
asmlinkage void do_illegal_instruction(struct pt_regs *regs,
unsigned long address);
static void print_trace(void *data, unsigned long addr, int reliable)
{
const char *loglvl = data;
pr_info("%s[<%p>] %s%pS\n", loglvl, (void *) addr, reliable ? "" : "? ",
(void *) addr);
}
static void print_data(unsigned long base_addr, unsigned long word, int i)
{
if (i == 0)
pr_info("(%08lx:)\t%08lx", base_addr + (i * 4), word);
else
pr_info(" %08lx:\t%08lx", base_addr + (i * 4), word);
}
/* displays a short stack trace */
void show_stack(struct task_struct *task, unsigned long *esp, const char *loglvl)
{
if (esp == NULL)
esp = (unsigned long *)&esp;
pr_info("%sCall trace:\n", loglvl);
unwind_stack((void *)loglvl, esp, print_trace);
}
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;
pr_info("CPU #: %d\n"
" PC: %08lx SR: %08lx SP: %08lx FPCSR: %08lx\n",
smp_processor_id(), regs->pc, regs->sr, regs->sp,
regs->fpcsr);
pr_info("GPR00: %08lx GPR01: %08lx GPR02: %08lx GPR03: %08lx\n",
0L, regs->gpr[1], regs->gpr[2], regs->gpr[3]);
pr_info("GPR04: %08lx GPR05: %08lx GPR06: %08lx GPR07: %08lx\n",
regs->gpr[4], regs->gpr[5], regs->gpr[6], regs->gpr[7]);
pr_info("GPR08: %08lx GPR09: %08lx GPR10: %08lx GPR11: %08lx\n",
regs->gpr[8], regs->gpr[9], regs->gpr[10], regs->gpr[11]);
pr_info("GPR12: %08lx GPR13: %08lx GPR14: %08lx GPR15: %08lx\n",
regs->gpr[12], regs->gpr[13], regs->gpr[14], regs->gpr[15]);
pr_info("GPR16: %08lx GPR17: %08lx GPR18: %08lx GPR19: %08lx\n",
regs->gpr[16], regs->gpr[17], regs->gpr[18], regs->gpr[19]);
pr_info("GPR20: %08lx GPR21: %08lx GPR22: %08lx GPR23: %08lx\n",
regs->gpr[20], regs->gpr[21], regs->gpr[22], regs->gpr[23]);
pr_info("GPR24: %08lx GPR25: %08lx GPR26: %08lx GPR27: %08lx\n",
regs->gpr[24], regs->gpr[25], regs->gpr[26], regs->gpr[27]);
pr_info("GPR28: %08lx GPR29: %08lx GPR30: %08lx GPR31: %08lx\n",
regs->gpr[28], regs->gpr[29], regs->gpr[30], regs->gpr[31]);
pr_info(" RES: %08lx oGPR11: %08lx\n",
regs->gpr[11], regs->orig_gpr11);
pr_info("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) {
pr_info("\nStack: ");
show_stack(NULL, (unsigned long *)esp, KERN_EMERG);
if (esp < PAGE_OFFSET)
goto bad_stack;
pr_info("\n");
for (i = -8; i < 24; i += 1) {
unsigned long word;
if (__get_user(word, &((unsigned long *)esp)[i])) {
bad_stack:
pr_info(" Bad Stack value.");
break;
}
print_data(esp, word, i);
}
pr_info("\nCode: ");
if (regs->pc < PAGE_OFFSET)
goto bad;
for (i = -6; i < 6; i += 1) {
unsigned long word;
if (__get_user(word, &((unsigned long *)regs->pc)[i])) {
bad:
pr_info(" Bad PC value.");
break;
}
print_data(regs->pc, word, i);
}
}
pr_info("\n");
}
/* This is normally the 'Oops' routine */
void __noreturn die(const char *str, struct pt_regs *regs, long err)
{
console_verbose();
pr_emerg("\n%s#: %04lx\n", str, err & 0xffff);
show_registers(regs);
#ifdef CONFIG_JUMP_UPON_UNHANDLED_EXCEPTION
pr_emerg("\n\nUNHANDLED_EXCEPTION: entering infinite loop\n");
/* shut down interrupts */
local_irq_disable();
__asm__ __volatile__("l.nop 1");
do {} while (1);
#endif
make_task_dead(SIGSEGV);
}
asmlinkage void unhandled_exception(struct pt_regs *regs, int ea, int vector)
{
pr_emerg("Unable to handle exception at EA =0x%x, vector 0x%x",
ea, vector);
die("Oops", regs, 9);
}
asmlinkage void do_fpe_trap(struct pt_regs *regs, unsigned long address)
{
int code = FPE_FLTUNK;
unsigned long fpcsr = regs->fpcsr;
if (fpcsr & SPR_FPCSR_IVF)
code = FPE_FLTINV;
else if (fpcsr & SPR_FPCSR_OVF)
code = FPE_FLTOVF;
else if (fpcsr & SPR_FPCSR_UNF)
code = FPE_FLTUND;
else if (fpcsr & SPR_FPCSR_DZF)
code = FPE_FLTDIV;
else if (fpcsr & SPR_FPCSR_IXF)
code = FPE_FLTRES;
/* Clear all flags */
regs->fpcsr &= ~SPR_FPCSR_ALLF;
force_sig_fault(SIGFPE, code, (void __user *)regs->pc);
}
asmlinkage void do_trap(struct pt_regs *regs, unsigned long address)
{
force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->pc);
}
asmlinkage void do_unaligned_access(struct pt_regs *regs, unsigned long address)
{
if (user_mode(regs)) {
/* Send a SIGBUS */
force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *)address);
} else {
pr_emerg("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)
{
if (user_mode(regs)) {
/* Send a SIGBUS */
force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)address);
} else { /* Kernel mode */
pr_emerg("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 mfspr(SPR_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);
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);
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)
{
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 */
force_sig_fault(SIGILL, ILL_ILLOPC, (void __user *)address);
} else { /* Kernel mode */
pr_emerg("KERNEL: Illegal instruction (SIGILL) 0x%.8lx\n",
address);
show_registers(regs);
die("Die:", regs, address);
}
}
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