diff options
Diffstat (limited to 'arch/riscv/kernel/traps.c')
| -rw-r--r-- | arch/riscv/kernel/traps.c | 435 |
1 files changed, 435 insertions, 0 deletions
diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c new file mode 100644 index 0000000000..67d0073fb6 --- /dev/null +++ b/arch/riscv/kernel/traps.c @@ -0,0 +1,435 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (C) 2012 Regents of the University of California + */ + +#include <linux/cpu.h> +#include <linux/kernel.h> +#include <linux/init.h> +#include <linux/sched.h> +#include <linux/sched/debug.h> +#include <linux/sched/signal.h> +#include <linux/signal.h> +#include <linux/kdebug.h> +#include <linux/uaccess.h> +#include <linux/kprobes.h> +#include <linux/uprobes.h> +#include <asm/uprobes.h> +#include <linux/mm.h> +#include <linux/module.h> +#include <linux/irq.h> +#include <linux/kexec.h> +#include <linux/entry-common.h> + +#include <asm/asm-prototypes.h> +#include <asm/bug.h> +#include <asm/cfi.h> +#include <asm/csr.h> +#include <asm/processor.h> +#include <asm/ptrace.h> +#include <asm/syscall.h> +#include <asm/thread_info.h> +#include <asm/vector.h> +#include <asm/irq_stack.h> + +int show_unhandled_signals = 1; + +static DEFINE_SPINLOCK(die_lock); + +static void dump_kernel_instr(const char *loglvl, struct pt_regs *regs) +{ + char str[sizeof("0000 ") * 12 + 2 + 1], *p = str; + const u16 *insns = (u16 *)instruction_pointer(regs); + long bad; + u16 val; + int i; + + for (i = -10; i < 2; i++) { + bad = get_kernel_nofault(val, &insns[i]); + if (!bad) { + p += sprintf(p, i == 0 ? "(%04hx) " : "%04hx ", val); + } else { + printk("%sCode: Unable to access instruction at 0x%px.\n", + loglvl, &insns[i]); + return; + } + } + printk("%sCode: %s\n", loglvl, str); +} + +void die(struct pt_regs *regs, const char *str) +{ + static int die_counter; + int ret; + long cause; + unsigned long flags; + + oops_enter(); + + spin_lock_irqsave(&die_lock, flags); + console_verbose(); + bust_spinlocks(1); + + pr_emerg("%s [#%d]\n", str, ++die_counter); + print_modules(); + if (regs) { + show_regs(regs); + dump_kernel_instr(KERN_EMERG, regs); + } + + cause = regs ? regs->cause : -1; + ret = notify_die(DIE_OOPS, str, regs, 0, cause, SIGSEGV); + + if (kexec_should_crash(current)) + crash_kexec(regs); + + bust_spinlocks(0); + add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); + spin_unlock_irqrestore(&die_lock, flags); + oops_exit(); + + if (in_interrupt()) + panic("Fatal exception in interrupt"); + if (panic_on_oops) + panic("Fatal exception"); + if (ret != NOTIFY_STOP) + make_task_dead(SIGSEGV); +} + +void do_trap(struct pt_regs *regs, int signo, int code, unsigned long addr) +{ + struct task_struct *tsk = current; + + if (show_unhandled_signals && unhandled_signal(tsk, signo) + && printk_ratelimit()) { + pr_info("%s[%d]: unhandled signal %d code 0x%x at 0x" REG_FMT, + tsk->comm, task_pid_nr(tsk), signo, code, addr); + print_vma_addr(KERN_CONT " in ", instruction_pointer(regs)); + pr_cont("\n"); + __show_regs(regs); + } + + force_sig_fault(signo, code, (void __user *)addr); +} + +static void do_trap_error(struct pt_regs *regs, int signo, int code, + unsigned long addr, const char *str) +{ + current->thread.bad_cause = regs->cause; + + if (user_mode(regs)) { + do_trap(regs, signo, code, addr); + } else { + if (!fixup_exception(regs)) + die(regs, str); + } +} + +#if defined(CONFIG_XIP_KERNEL) && defined(CONFIG_RISCV_ALTERNATIVE) +#define __trap_section __noinstr_section(".xip.traps") +#else +#define __trap_section noinstr +#endif +#define DO_ERROR_INFO(name, signo, code, str) \ +asmlinkage __visible __trap_section void name(struct pt_regs *regs) \ +{ \ + if (user_mode(regs)) { \ + irqentry_enter_from_user_mode(regs); \ + do_trap_error(regs, signo, code, regs->epc, "Oops - " str); \ + irqentry_exit_to_user_mode(regs); \ + } else { \ + irqentry_state_t state = irqentry_nmi_enter(regs); \ + do_trap_error(regs, signo, code, regs->epc, "Oops - " str); \ + irqentry_nmi_exit(regs, state); \ + } \ +} + +DO_ERROR_INFO(do_trap_unknown, + SIGILL, ILL_ILLTRP, "unknown exception"); +DO_ERROR_INFO(do_trap_insn_misaligned, + SIGBUS, BUS_ADRALN, "instruction address misaligned"); +DO_ERROR_INFO(do_trap_insn_fault, + SIGSEGV, SEGV_ACCERR, "instruction access fault"); + +asmlinkage __visible __trap_section void do_trap_insn_illegal(struct pt_regs *regs) +{ + bool handled; + + if (user_mode(regs)) { + irqentry_enter_from_user_mode(regs); + + local_irq_enable(); + + handled = riscv_v_first_use_handler(regs); + + local_irq_disable(); + + if (!handled) + do_trap_error(regs, SIGILL, ILL_ILLOPC, regs->epc, + "Oops - illegal instruction"); + + irqentry_exit_to_user_mode(regs); + } else { + irqentry_state_t state = irqentry_nmi_enter(regs); + + do_trap_error(regs, SIGILL, ILL_ILLOPC, regs->epc, + "Oops - illegal instruction"); + + irqentry_nmi_exit(regs, state); + } +} + +DO_ERROR_INFO(do_trap_load_fault, + SIGSEGV, SEGV_ACCERR, "load access fault"); +#ifndef CONFIG_RISCV_M_MODE +DO_ERROR_INFO(do_trap_load_misaligned, + SIGBUS, BUS_ADRALN, "Oops - load address misaligned"); +DO_ERROR_INFO(do_trap_store_misaligned, + SIGBUS, BUS_ADRALN, "Oops - store (or AMO) address misaligned"); +#else +int handle_misaligned_load(struct pt_regs *regs); +int handle_misaligned_store(struct pt_regs *regs); + +asmlinkage __visible __trap_section void do_trap_load_misaligned(struct pt_regs *regs) +{ + if (user_mode(regs)) { + irqentry_enter_from_user_mode(regs); + + if (handle_misaligned_load(regs)) + do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc, + "Oops - load address misaligned"); + + irqentry_exit_to_user_mode(regs); + } else { + irqentry_state_t state = irqentry_nmi_enter(regs); + + if (handle_misaligned_load(regs)) + do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc, + "Oops - load address misaligned"); + + irqentry_nmi_exit(regs, state); + } +} + +asmlinkage __visible __trap_section void do_trap_store_misaligned(struct pt_regs *regs) +{ + if (user_mode(regs)) { + irqentry_enter_from_user_mode(regs); + + if (handle_misaligned_store(regs)) + do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc, + "Oops - store (or AMO) address misaligned"); + + irqentry_exit_to_user_mode(regs); + } else { + irqentry_state_t state = irqentry_nmi_enter(regs); + + if (handle_misaligned_store(regs)) + do_trap_error(regs, SIGBUS, BUS_ADRALN, regs->epc, + "Oops - store (or AMO) address misaligned"); + + irqentry_nmi_exit(regs, state); + } +} +#endif +DO_ERROR_INFO(do_trap_store_fault, + SIGSEGV, SEGV_ACCERR, "store (or AMO) access fault"); +DO_ERROR_INFO(do_trap_ecall_s, + SIGILL, ILL_ILLTRP, "environment call from S-mode"); +DO_ERROR_INFO(do_trap_ecall_m, + SIGILL, ILL_ILLTRP, "environment call from M-mode"); + +static inline unsigned long get_break_insn_length(unsigned long pc) +{ + bug_insn_t insn; + + if (get_kernel_nofault(insn, (bug_insn_t *)pc)) + return 0; + + return GET_INSN_LENGTH(insn); +} + +static bool probe_single_step_handler(struct pt_regs *regs) +{ + bool user = user_mode(regs); + + return user ? uprobe_single_step_handler(regs) : kprobe_single_step_handler(regs); +} + +static bool probe_breakpoint_handler(struct pt_regs *regs) +{ + bool user = user_mode(regs); + + return user ? uprobe_breakpoint_handler(regs) : kprobe_breakpoint_handler(regs); +} + +void handle_break(struct pt_regs *regs) +{ + if (probe_single_step_handler(regs)) + return; + + if (probe_breakpoint_handler(regs)) + return; + + current->thread.bad_cause = regs->cause; + + if (user_mode(regs)) + force_sig_fault(SIGTRAP, TRAP_BRKPT, (void __user *)regs->epc); +#ifdef CONFIG_KGDB + else if (notify_die(DIE_TRAP, "EBREAK", regs, 0, regs->cause, SIGTRAP) + == NOTIFY_STOP) + return; +#endif + else if (report_bug(regs->epc, regs) == BUG_TRAP_TYPE_WARN || + handle_cfi_failure(regs) == BUG_TRAP_TYPE_WARN) + regs->epc += get_break_insn_length(regs->epc); + else + die(regs, "Kernel BUG"); +} + +asmlinkage __visible __trap_section void do_trap_break(struct pt_regs *regs) +{ + if (user_mode(regs)) { + irqentry_enter_from_user_mode(regs); + + handle_break(regs); + + irqentry_exit_to_user_mode(regs); + } else { + irqentry_state_t state = irqentry_nmi_enter(regs); + + handle_break(regs); + + irqentry_nmi_exit(regs, state); + } +} + +asmlinkage __visible __trap_section void do_trap_ecall_u(struct pt_regs *regs) +{ + if (user_mode(regs)) { + long syscall = regs->a7; + + regs->epc += 4; + regs->orig_a0 = regs->a0; + + riscv_v_vstate_discard(regs); + + syscall = syscall_enter_from_user_mode(regs, syscall); + + if (syscall >= 0 && syscall < NR_syscalls) + syscall_handler(regs, syscall); + else if (syscall != -1) + regs->a0 = -ENOSYS; + + syscall_exit_to_user_mode(regs); + } else { + irqentry_state_t state = irqentry_nmi_enter(regs); + + do_trap_error(regs, SIGILL, ILL_ILLTRP, regs->epc, + "Oops - environment call from U-mode"); + + irqentry_nmi_exit(regs, state); + } + +} + +#ifdef CONFIG_MMU +asmlinkage __visible noinstr void do_page_fault(struct pt_regs *regs) +{ + irqentry_state_t state = irqentry_enter(regs); + + handle_page_fault(regs); + + local_irq_disable(); + + irqentry_exit(regs, state); +} +#endif + +static void noinstr handle_riscv_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_irq(struct pt_regs *regs) +{ + irqentry_state_t state = irqentry_enter(regs); +#ifdef CONFIG_IRQ_STACKS + if (on_thread_stack()) { + ulong *sp = per_cpu(irq_stack_ptr, smp_processor_id()) + + IRQ_STACK_SIZE/sizeof(ulong); + __asm__ __volatile( + "addi sp, sp, -"RISCV_SZPTR "\n" + REG_S" ra, (sp) \n" + "addi sp, sp, -"RISCV_SZPTR "\n" + REG_S" s0, (sp) \n" + "addi s0, sp, 2*"RISCV_SZPTR "\n" + "move sp, %[sp] \n" + "move a0, %[regs] \n" + "call handle_riscv_irq \n" + "addi sp, s0, -2*"RISCV_SZPTR"\n" + REG_L" s0, (sp) \n" + "addi sp, sp, "RISCV_SZPTR "\n" + REG_L" ra, (sp) \n" + "addi sp, sp, "RISCV_SZPTR "\n" + : + : [sp] "r" (sp), [regs] "r" (regs) + : "a0", "a1", "a2", "a3", "a4", "a5", "a6", "a7", + "t0", "t1", "t2", "t3", "t4", "t5", "t6", +#ifndef CONFIG_FRAME_POINTER + "s0", +#endif + "memory"); + } else +#endif + handle_riscv_irq(regs); + + irqentry_exit(regs, state); +} + +#ifdef CONFIG_GENERIC_BUG +int is_valid_bugaddr(unsigned long pc) +{ + bug_insn_t insn; + + if (pc < VMALLOC_START) + return 0; + if (get_kernel_nofault(insn, (bug_insn_t *)pc)) + return 0; + if ((insn & __INSN_LENGTH_MASK) == __INSN_LENGTH_32) + return (insn == __BUG_INSN_32); + else + return ((insn & __COMPRESSED_INSN_MASK) == __BUG_INSN_16); +} +#endif /* CONFIG_GENERIC_BUG */ + +#ifdef CONFIG_VMAP_STACK +DEFINE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], + overflow_stack)__aligned(16); + +asmlinkage void handle_bad_stack(struct pt_regs *regs) +{ + unsigned long tsk_stk = (unsigned long)current->stack; + unsigned long ovf_stk = (unsigned long)this_cpu_ptr(overflow_stack); + + console_verbose(); + + pr_emerg("Insufficient stack space to handle exception!\n"); + pr_emerg("Task stack: [0x%016lx..0x%016lx]\n", + tsk_stk, tsk_stk + THREAD_SIZE); + pr_emerg("Overflow stack: [0x%016lx..0x%016lx]\n", + ovf_stk, ovf_stk + OVERFLOW_STACK_SIZE); + + __show_regs(regs); + panic("Kernel stack overflow"); + + for (;;) + wait_for_interrupt(); +} +#endif |