diff options
Diffstat (limited to 'arch/loongarch/kernel/traps.c')
| -rw-r--r-- | arch/loongarch/kernel/traps.c | 725 |
1 files changed, 725 insertions, 0 deletions
diff --git a/arch/loongarch/kernel/traps.c b/arch/loongarch/kernel/traps.c new file mode 100644 index 000000000000..e4060f84a221 --- /dev/null +++ b/arch/loongarch/kernel/traps.c @@ -0,0 +1,725 @@ +// 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 "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; + unsigned long *sp = (unsigned long *)(regs->regs[3] & ~3); + + printk("%sCall Trace:", loglvl); +#ifdef CONFIG_KALLSYMS + printk("%s\n", loglvl); +#endif + while (!kstack_end(sp)) { + if (__get_addr(&addr, sp++, user)) { + printk("%s (Bad stack address)", loglvl); + break; + } + if (__kernel_text_address(addr)) + 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(®s); + 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, ®s, 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); + + if (unlikely(compute_return_era(regs) < 0)) + goto out; + + 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); +} |