OpenCloudOS-Kernel/arch/loongarch/kernel/traps.c

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// SPDX-License-Identifier: GPL-2.0
/*
* Author: Huacai Chen <chenhuacai@loongson.cn>
* Copyright (C) 2020-2022 Loongson Technology Corporation Limited
*/
#include <linux/bitops.h>
#include <linux/bug.h>
#include <linux/compiler.h>
#include <linux/context_tracking.h>
#include <linux/entry-common.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/extable.h>
#include <linux/mm.h>
#include <linux/sched/mm.h>
#include <linux/sched/debug.h>
#include <linux/smp.h>
#include <linux/spinlock.h>
#include <linux/kallsyms.h>
#include <linux/memblock.h>
#include <linux/interrupt.h>
#include <linux/ptrace.h>
#include <linux/kgdb.h>
#include <linux/kdebug.h>
#include <linux/kprobes.h>
#include <linux/notifier.h>
#include <linux/irq.h>
#include <linux/perf_event.h>
#include <asm/addrspace.h>
#include <asm/bootinfo.h>
#include <asm/branch.h>
#include <asm/break.h>
#include <asm/cpu.h>
#include <asm/fpu.h>
#include <asm/loongarch.h>
#include <asm/mmu_context.h>
#include <asm/pgtable.h>
#include <asm/ptrace.h>
#include <asm/sections.h>
#include <asm/siginfo.h>
#include <asm/stacktrace.h>
#include <asm/tlb.h>
#include <asm/types.h>
#include <asm/unwind.h>
#include "access-helper.h"
extern asmlinkage void handle_ade(void);
extern asmlinkage void handle_ale(void);
extern asmlinkage void handle_sys(void);
extern asmlinkage void handle_bp(void);
extern asmlinkage void handle_ri(void);
extern asmlinkage void handle_fpu(void);
extern asmlinkage void handle_fpe(void);
extern asmlinkage void handle_lbt(void);
extern asmlinkage void handle_lsx(void);
extern asmlinkage void handle_lasx(void);
extern asmlinkage void handle_reserved(void);
extern asmlinkage void handle_watch(void);
extern asmlinkage void handle_vint(void);
static void show_backtrace(struct task_struct *task, const struct pt_regs *regs,
const char *loglvl, bool user)
{
unsigned long addr;
struct unwind_state state;
struct pt_regs *pregs = (struct pt_regs *)regs;
if (!task)
task = current;
if (user_mode(regs))
state.type = UNWINDER_GUESS;
printk("%sCall Trace:", loglvl);
for (unwind_start(&state, task, pregs);
!unwind_done(&state); unwind_next_frame(&state)) {
addr = unwind_get_return_address(&state);
print_ip_sym(loglvl, addr);
}
printk("%s\n", loglvl);
}
static void show_stacktrace(struct task_struct *task,
const struct pt_regs *regs, const char *loglvl, bool user)
{
int i;
const int field = 2 * sizeof(unsigned long);
unsigned long stackdata;
unsigned long *sp = (unsigned long *)regs->regs[3];
printk("%sStack :", loglvl);
i = 0;
while ((unsigned long) sp & (PAGE_SIZE - 1)) {
if (i && ((i % (64 / field)) == 0)) {
pr_cont("\n");
printk("%s ", loglvl);
}
if (i > 39) {
pr_cont(" ...");
break;
}
if (__get_addr(&stackdata, sp++, user)) {
pr_cont(" (Bad stack address)");
break;
}
pr_cont(" %0*lx", field, stackdata);
i++;
}
pr_cont("\n");
show_backtrace(task, regs, loglvl, user);
}
void show_stack(struct task_struct *task, unsigned long *sp, const char *loglvl)
{
struct pt_regs regs;
regs.csr_crmd = 0;
if (sp) {
regs.csr_era = 0;
regs.regs[1] = 0;
regs.regs[3] = (unsigned long)sp;
} else {
if (!task || task == current)
prepare_frametrace(&regs);
else {
regs.csr_era = task->thread.reg01;
regs.regs[1] = 0;
regs.regs[3] = task->thread.reg03;
regs.regs[22] = task->thread.reg22;
}
}
show_stacktrace(task, &regs, loglvl, false);
}
static void show_code(unsigned int *pc, bool user)
{
long i;
unsigned int insn;
printk("Code:");
for(i = -3 ; i < 6 ; i++) {
if (__get_inst(&insn, pc + i, user)) {
pr_cont(" (Bad address in era)\n");
break;
}
pr_cont("%c%08x%c", (i?' ':'<'), insn, (i?' ':'>'));
}
pr_cont("\n");
}
static void __show_regs(const struct pt_regs *regs)
{
const int field = 2 * sizeof(unsigned long);
unsigned int excsubcode;
unsigned int exccode;
int i;
show_regs_print_info(KERN_DEFAULT);
/*
* Saved main processor registers
*/
for (i = 0; i < 32; ) {
if ((i % 4) == 0)
printk("$%2d :", i);
pr_cont(" %0*lx", field, regs->regs[i]);
i++;
if ((i % 4) == 0)
pr_cont("\n");
}
/*
* Saved csr registers
*/
printk("era : %0*lx %pS\n", field, regs->csr_era,
(void *) regs->csr_era);
printk("ra : %0*lx %pS\n", field, regs->regs[1],
(void *) regs->regs[1]);
printk("CSR crmd: %08lx ", regs->csr_crmd);
printk("CSR prmd: %08lx ", regs->csr_prmd);
printk("CSR euen: %08lx ", regs->csr_euen);
printk("CSR ecfg: %08lx ", regs->csr_ecfg);
printk("CSR estat: %08lx ", regs->csr_estat);
pr_cont("\n");
exccode = ((regs->csr_estat) & CSR_ESTAT_EXC) >> CSR_ESTAT_EXC_SHIFT;
excsubcode = ((regs->csr_estat) & CSR_ESTAT_ESUBCODE) >> CSR_ESTAT_ESUBCODE_SHIFT;
printk("ExcCode : %x (SubCode %x)\n", exccode, excsubcode);
if (exccode >= EXCCODE_TLBL && exccode <= EXCCODE_ALE)
printk("BadVA : %0*lx\n", field, regs->csr_badvaddr);
printk("PrId : %08x (%s)\n", read_cpucfg(LOONGARCH_CPUCFG0),
cpu_family_string());
}
void show_regs(struct pt_regs *regs)
{
__show_regs((struct pt_regs *)regs);
dump_stack();
}
void show_registers(struct pt_regs *regs)
{
__show_regs(regs);
print_modules();
printk("Process %s (pid: %d, threadinfo=%p, task=%p)\n",
current->comm, current->pid, current_thread_info(), current);
show_stacktrace(current, regs, KERN_DEFAULT, user_mode(regs));
show_code((void *)regs->csr_era, user_mode(regs));
printk("\n");
}
static DEFINE_RAW_SPINLOCK(die_lock);
void __noreturn die(const char *str, struct pt_regs *regs)
{
static int die_counter;
int sig = SIGSEGV;
oops_enter();
if (notify_die(DIE_OOPS, str, regs, 0, current->thread.trap_nr,
SIGSEGV) == NOTIFY_STOP)
sig = 0;
console_verbose();
raw_spin_lock_irq(&die_lock);
bust_spinlocks(1);
printk("%s[#%d]:\n", str, ++die_counter);
show_registers(regs);
add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
raw_spin_unlock_irq(&die_lock);
oops_exit();
if (in_interrupt())
panic("Fatal exception in interrupt");
if (panic_on_oops)
panic("Fatal exception");
make_task_dead(sig);
}
static inline void setup_vint_size(unsigned int size)
{
unsigned int vs;
vs = ilog2(size/4);
if (vs == 0 || vs > 7)
panic("vint_size %d Not support yet", vs);
csr_xchg32(vs<<CSR_ECFG_VS_SHIFT, CSR_ECFG_VS, LOONGARCH_CSR_ECFG);
}
/*
* Send SIGFPE according to FCSR Cause bits, which must have already
* been masked against Enable bits. This is impotant as Inexact can
* happen together with Overflow or Underflow, and `ptrace' can set
* any bits.
*/
void force_fcsr_sig(unsigned long fcsr, void __user *fault_addr,
struct task_struct *tsk)
{
int si_code = FPE_FLTUNK;
if (fcsr & FPU_CSR_INV_X)
si_code = FPE_FLTINV;
else if (fcsr & FPU_CSR_DIV_X)
si_code = FPE_FLTDIV;
else if (fcsr & FPU_CSR_OVF_X)
si_code = FPE_FLTOVF;
else if (fcsr & FPU_CSR_UDF_X)
si_code = FPE_FLTUND;
else if (fcsr & FPU_CSR_INE_X)
si_code = FPE_FLTRES;
force_sig_fault(SIGFPE, si_code, fault_addr);
}
int process_fpemu_return(int sig, void __user *fault_addr, unsigned long fcsr)
{
int si_code;
switch (sig) {
case 0:
return 0;
case SIGFPE:
force_fcsr_sig(fcsr, fault_addr, current);
return 1;
case SIGBUS:
force_sig_fault(SIGBUS, BUS_ADRERR, fault_addr);
return 1;
case SIGSEGV:
mmap_read_lock(current->mm);
if (vma_lookup(current->mm, (unsigned long)fault_addr))
si_code = SEGV_ACCERR;
else
si_code = SEGV_MAPERR;
mmap_read_unlock(current->mm);
force_sig_fault(SIGSEGV, si_code, fault_addr);
return 1;
default:
force_sig(sig);
return 1;
}
}
/*
* Delayed fp exceptions when doing a lazy ctx switch
*/
asmlinkage void noinstr do_fpe(struct pt_regs *regs, unsigned long fcsr)
{
int sig;
void __user *fault_addr;
irqentry_state_t state = irqentry_enter(regs);
if (notify_die(DIE_FP, "FP exception", regs, 0, current->thread.trap_nr,
SIGFPE) == NOTIFY_STOP)
goto out;
/* Clear FCSR.Cause before enabling interrupts */
write_fcsr(LOONGARCH_FCSR0, fcsr & ~mask_fcsr_x(fcsr));
local_irq_enable();
die_if_kernel("FP exception in kernel code", regs);
sig = SIGFPE;
fault_addr = (void __user *) regs->csr_era;
/* Send a signal if required. */
process_fpemu_return(sig, fault_addr, fcsr);
out:
local_irq_disable();
irqentry_exit(regs, state);
}
asmlinkage void noinstr do_ade(struct pt_regs *regs)
{
irqentry_state_t state = irqentry_enter(regs);
die_if_kernel("Kernel ade access", regs);
force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)regs->csr_badvaddr);
irqentry_exit(regs, state);
}
asmlinkage void noinstr do_ale(struct pt_regs *regs)
{
irqentry_state_t state = irqentry_enter(regs);
die_if_kernel("Kernel ale access", regs);
force_sig_fault(SIGBUS, BUS_ADRALN, (void __user *)regs->csr_badvaddr);
irqentry_exit(regs, state);
}
asmlinkage void noinstr do_bp(struct pt_regs *regs)
{
bool user = user_mode(regs);
unsigned int opcode, bcode;
unsigned long era = exception_era(regs);
irqentry_state_t state = irqentry_enter(regs);
local_irq_enable();
current->thread.trap_nr = read_csr_excode();
if (__get_inst(&opcode, (u32 *)era, user))
goto out_sigsegv;
bcode = (opcode & 0x7fff);
/*
* notify the kprobe handlers, if instruction is likely to
* pertain to them.
*/
switch (bcode) {
case BRK_KPROBE_BP:
if (notify_die(DIE_BREAK, "Kprobe", regs, bcode,
current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
goto out;
else
break;
case BRK_KPROBE_SSTEPBP:
if (notify_die(DIE_SSTEPBP, "Kprobe_SingleStep", regs, bcode,
current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
goto out;
else
break;
case BRK_UPROBE_BP:
if (notify_die(DIE_UPROBE, "Uprobe", regs, bcode,
current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
goto out;
else
break;
case BRK_UPROBE_XOLBP:
if (notify_die(DIE_UPROBE_XOL, "Uprobe_XOL", regs, bcode,
current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
goto out;
else
break;
default:
if (notify_die(DIE_TRAP, "Break", regs, bcode,
current->thread.trap_nr, SIGTRAP) == NOTIFY_STOP)
goto out;
else
break;
}
switch (bcode) {
case BRK_BUG:
die_if_kernel("Kernel bug detected", regs);
force_sig(SIGTRAP);
break;
case BRK_DIVZERO:
die_if_kernel("Break instruction in kernel code", regs);
force_sig_fault(SIGFPE, FPE_INTDIV, (void __user *)regs->csr_era);
break;
case BRK_OVERFLOW:
die_if_kernel("Break instruction in kernel code", regs);
force_sig_fault(SIGFPE, FPE_INTOVF, (void __user *)regs->csr_era);
break;
default:
die_if_kernel("Break instruction in kernel code", regs);
force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->csr_era);
break;
}
out:
local_irq_disable();
irqentry_exit(regs, state);
return;
out_sigsegv:
force_sig(SIGSEGV);
goto out;
}
asmlinkage void noinstr do_watch(struct pt_regs *regs)
{
pr_warn("Hardware watch point handler not implemented!\n");
}
asmlinkage void noinstr do_ri(struct pt_regs *regs)
{
int status = -1;
unsigned int opcode = 0;
unsigned int __user *era = (unsigned int __user *)exception_era(regs);
unsigned long old_era = regs->csr_era;
unsigned long old_ra = regs->regs[1];
irqentry_state_t state = irqentry_enter(regs);
local_irq_enable();
current->thread.trap_nr = read_csr_excode();
if (notify_die(DIE_RI, "RI Fault", regs, 0, current->thread.trap_nr,
SIGILL) == NOTIFY_STOP)
goto out;
die_if_kernel("Reserved instruction in kernel code", regs);
compute_return_era(regs);
if (unlikely(get_user(opcode, era) < 0)) {
status = SIGSEGV;
current->thread.error_code = 1;
}
if (status < 0)
status = SIGILL;
if (unlikely(status > 0)) {
regs->csr_era = old_era; /* Undo skip-over. */
regs->regs[1] = old_ra;
force_sig(status);
}
out:
local_irq_disable();
irqentry_exit(regs, state);
}
static void init_restore_fp(void)
{
if (!used_math()) {
/* First time FP context user. */
init_fpu();
} else {
/* This task has formerly used the FP context */
if (!is_fpu_owner())
own_fpu_inatomic(1);
}
BUG_ON(!is_fp_enabled());
}
asmlinkage void noinstr do_fpu(struct pt_regs *regs)
{
irqentry_state_t state = irqentry_enter(regs);
local_irq_enable();
die_if_kernel("do_fpu invoked from kernel context!", regs);
preempt_disable();
init_restore_fp();
preempt_enable();
local_irq_disable();
irqentry_exit(regs, state);
}
asmlinkage void noinstr do_lsx(struct pt_regs *regs)
{
irqentry_state_t state = irqentry_enter(regs);
local_irq_enable();
force_sig(SIGILL);
local_irq_disable();
irqentry_exit(regs, state);
}
asmlinkage void noinstr do_lasx(struct pt_regs *regs)
{
irqentry_state_t state = irqentry_enter(regs);
local_irq_enable();
force_sig(SIGILL);
local_irq_disable();
irqentry_exit(regs, state);
}
asmlinkage void noinstr do_lbt(struct pt_regs *regs)
{
irqentry_state_t state = irqentry_enter(regs);
local_irq_enable();
force_sig(SIGILL);
local_irq_disable();
irqentry_exit(regs, state);
}
asmlinkage void noinstr do_reserved(struct pt_regs *regs)
{
irqentry_state_t state = irqentry_enter(regs);
local_irq_enable();
/*
* Game over - no way to handle this if it ever occurs. Most probably
* caused by a fatal error after another hardware/software error.
*/
pr_err("Caught reserved exception %u on pid:%d [%s] - should not happen\n",
read_csr_excode(), current->pid, current->comm);
die_if_kernel("do_reserved exception", regs);
force_sig(SIGUNUSED);
local_irq_disable();
irqentry_exit(regs, state);
}
asmlinkage void cache_parity_error(void)
{
/* For the moment, report the problem and hang. */
pr_err("Cache error exception:\n");
pr_err("csr_merrctl == %08x\n", csr_read32(LOONGARCH_CSR_MERRCTL));
pr_err("csr_merrera == %016llx\n", csr_read64(LOONGARCH_CSR_MERRERA));
panic("Can't handle the cache error!");
}
asmlinkage void noinstr handle_loongarch_irq(struct pt_regs *regs)
{
struct pt_regs *old_regs;
irq_enter_rcu();
old_regs = set_irq_regs(regs);
handle_arch_irq(regs);
set_irq_regs(old_regs);
irq_exit_rcu();
}
asmlinkage void noinstr do_vint(struct pt_regs *regs, unsigned long sp)
{
register int cpu;
register unsigned long stack;
irqentry_state_t state = irqentry_enter(regs);
cpu = smp_processor_id();
if (on_irq_stack(cpu, sp))
handle_loongarch_irq(regs);
else {
stack = per_cpu(irq_stack, cpu) + IRQ_STACK_START;
/* Save task's sp on IRQ stack for unwinding */
*(unsigned long *)stack = sp;
__asm__ __volatile__(
"move $s0, $sp \n" /* Preserve sp */
"move $sp, %[stk] \n" /* Switch stack */
"move $a0, %[regs] \n"
"bl handle_loongarch_irq \n"
"move $sp, $s0 \n" /* Restore sp */
: /* No outputs */
: [stk] "r" (stack), [regs] "r" (regs)
: "$a0", "$a1", "$a2", "$a3", "$a4", "$a5", "$a6", "$a7", "$s0",
"$t0", "$t1", "$t2", "$t3", "$t4", "$t5", "$t6", "$t7", "$t8",
"memory");
}
irqentry_exit(regs, state);
}
extern void tlb_init(int cpu);
extern void cache_error_setup(void);
unsigned long eentry;
unsigned long tlbrentry;
long exception_handlers[VECSIZE * 128 / sizeof(long)] __aligned(SZ_64K);
static void configure_exception_vector(void)
{
eentry = (unsigned long)exception_handlers;
tlbrentry = (unsigned long)exception_handlers + 80*VECSIZE;
csr_write64(eentry, LOONGARCH_CSR_EENTRY);
csr_write64(eentry, LOONGARCH_CSR_MERRENTRY);
csr_write64(tlbrentry, LOONGARCH_CSR_TLBRENTRY);
}
void per_cpu_trap_init(int cpu)
{
unsigned int i;
setup_vint_size(VECSIZE);
configure_exception_vector();
if (!cpu_data[cpu].asid_cache)
cpu_data[cpu].asid_cache = asid_first_version(cpu);
mmgrab(&init_mm);
current->active_mm = &init_mm;
BUG_ON(current->mm);
enter_lazy_tlb(&init_mm, current);
/* Initialise exception handlers */
if (cpu == 0)
for (i = 0; i < 64; i++)
set_handler(i * VECSIZE, handle_reserved, VECSIZE);
tlb_init(cpu);
cpu_cache_init();
}
/* Install CPU exception handler */
void set_handler(unsigned long offset, void *addr, unsigned long size)
{
memcpy((void *)(eentry + offset), addr, size);
local_flush_icache_range(eentry + offset, eentry + offset + size);
}
static const char panic_null_cerr[] =
"Trying to set NULL cache error exception handler\n";
/*
* Install uncached CPU exception handler.
* This is suitable only for the cache error exception which is the only
* exception handler that is being run uncached.
*/
void set_merr_handler(unsigned long offset, void *addr, unsigned long size)
{
unsigned long uncached_eentry = TO_UNCACHE(__pa(eentry));
if (!addr)
panic(panic_null_cerr);
memcpy((void *)(uncached_eentry + offset), addr, size);
}
void __init trap_init(void)
{
long i;
/* Set interrupt vector handler */
for (i = EXCCODE_INT_START; i < EXCCODE_INT_END; i++)
set_handler(i * VECSIZE, handle_vint, VECSIZE);
set_handler(EXCCODE_ADE * VECSIZE, handle_ade, VECSIZE);
set_handler(EXCCODE_ALE * VECSIZE, handle_ale, VECSIZE);
set_handler(EXCCODE_SYS * VECSIZE, handle_sys, VECSIZE);
set_handler(EXCCODE_BP * VECSIZE, handle_bp, VECSIZE);
set_handler(EXCCODE_INE * VECSIZE, handle_ri, VECSIZE);
set_handler(EXCCODE_IPE * VECSIZE, handle_ri, VECSIZE);
set_handler(EXCCODE_FPDIS * VECSIZE, handle_fpu, VECSIZE);
set_handler(EXCCODE_LSXDIS * VECSIZE, handle_lsx, VECSIZE);
set_handler(EXCCODE_LASXDIS * VECSIZE, handle_lasx, VECSIZE);
set_handler(EXCCODE_FPE * VECSIZE, handle_fpe, VECSIZE);
set_handler(EXCCODE_BTDIS * VECSIZE, handle_lbt, VECSIZE);
set_handler(EXCCODE_WATCH * VECSIZE, handle_watch, VECSIZE);
cache_error_setup();
local_flush_icache_range(eentry, eentry + 0x400);
}