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-rw-r--r--arch/riscv/kernel/traps.c435
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