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-rw-r--r--arch/arm64/kernel/traps.c1130
1 files changed, 1130 insertions, 0 deletions
diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
new file mode 100644
index 000000000..23d281ed7
--- /dev/null
+++ b/arch/arm64/kernel/traps.c
@@ -0,0 +1,1130 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Based on arch/arm/kernel/traps.c
+ *
+ * Copyright (C) 1995-2009 Russell King
+ * Copyright (C) 2012 ARM Ltd.
+ */
+
+#include <linux/bug.h>
+#include <linux/context_tracking.h>
+#include <linux/signal.h>
+#include <linux/kallsyms.h>
+#include <linux/kprobes.h>
+#include <linux/spinlock.h>
+#include <linux/uaccess.h>
+#include <linux/hardirq.h>
+#include <linux/kdebug.h>
+#include <linux/module.h>
+#include <linux/kexec.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/debug.h>
+#include <linux/sched/task_stack.h>
+#include <linux/sizes.h>
+#include <linux/syscalls.h>
+#include <linux/mm_types.h>
+#include <linux/kasan.h>
+#include <linux/cfi.h>
+
+#include <asm/atomic.h>
+#include <asm/bug.h>
+#include <asm/cpufeature.h>
+#include <asm/daifflags.h>
+#include <asm/debug-monitors.h>
+#include <asm/esr.h>
+#include <asm/exception.h>
+#include <asm/extable.h>
+#include <asm/insn.h>
+#include <asm/kprobes.h>
+#include <asm/patching.h>
+#include <asm/traps.h>
+#include <asm/smp.h>
+#include <asm/stack_pointer.h>
+#include <asm/stacktrace.h>
+#include <asm/system_misc.h>
+#include <asm/sysreg.h>
+
+static bool __kprobes __check_eq(unsigned long pstate)
+{
+ return (pstate & PSR_Z_BIT) != 0;
+}
+
+static bool __kprobes __check_ne(unsigned long pstate)
+{
+ return (pstate & PSR_Z_BIT) == 0;
+}
+
+static bool __kprobes __check_cs(unsigned long pstate)
+{
+ return (pstate & PSR_C_BIT) != 0;
+}
+
+static bool __kprobes __check_cc(unsigned long pstate)
+{
+ return (pstate & PSR_C_BIT) == 0;
+}
+
+static bool __kprobes __check_mi(unsigned long pstate)
+{
+ return (pstate & PSR_N_BIT) != 0;
+}
+
+static bool __kprobes __check_pl(unsigned long pstate)
+{
+ return (pstate & PSR_N_BIT) == 0;
+}
+
+static bool __kprobes __check_vs(unsigned long pstate)
+{
+ return (pstate & PSR_V_BIT) != 0;
+}
+
+static bool __kprobes __check_vc(unsigned long pstate)
+{
+ return (pstate & PSR_V_BIT) == 0;
+}
+
+static bool __kprobes __check_hi(unsigned long pstate)
+{
+ pstate &= ~(pstate >> 1); /* PSR_C_BIT &= ~PSR_Z_BIT */
+ return (pstate & PSR_C_BIT) != 0;
+}
+
+static bool __kprobes __check_ls(unsigned long pstate)
+{
+ pstate &= ~(pstate >> 1); /* PSR_C_BIT &= ~PSR_Z_BIT */
+ return (pstate & PSR_C_BIT) == 0;
+}
+
+static bool __kprobes __check_ge(unsigned long pstate)
+{
+ pstate ^= (pstate << 3); /* PSR_N_BIT ^= PSR_V_BIT */
+ return (pstate & PSR_N_BIT) == 0;
+}
+
+static bool __kprobes __check_lt(unsigned long pstate)
+{
+ pstate ^= (pstate << 3); /* PSR_N_BIT ^= PSR_V_BIT */
+ return (pstate & PSR_N_BIT) != 0;
+}
+
+static bool __kprobes __check_gt(unsigned long pstate)
+{
+ /*PSR_N_BIT ^= PSR_V_BIT */
+ unsigned long temp = pstate ^ (pstate << 3);
+
+ temp |= (pstate << 1); /*PSR_N_BIT |= PSR_Z_BIT */
+ return (temp & PSR_N_BIT) == 0;
+}
+
+static bool __kprobes __check_le(unsigned long pstate)
+{
+ /*PSR_N_BIT ^= PSR_V_BIT */
+ unsigned long temp = pstate ^ (pstate << 3);
+
+ temp |= (pstate << 1); /*PSR_N_BIT |= PSR_Z_BIT */
+ return (temp & PSR_N_BIT) != 0;
+}
+
+static bool __kprobes __check_al(unsigned long pstate)
+{
+ return true;
+}
+
+/*
+ * Note that the ARMv8 ARM calls condition code 0b1111 "nv", but states that
+ * it behaves identically to 0b1110 ("al").
+ */
+pstate_check_t * const aarch32_opcode_cond_checks[16] = {
+ __check_eq, __check_ne, __check_cs, __check_cc,
+ __check_mi, __check_pl, __check_vs, __check_vc,
+ __check_hi, __check_ls, __check_ge, __check_lt,
+ __check_gt, __check_le, __check_al, __check_al
+};
+
+int show_unhandled_signals = 0;
+
+static void dump_kernel_instr(const char *lvl, struct pt_regs *regs)
+{
+ unsigned long addr = instruction_pointer(regs);
+ char str[sizeof("00000000 ") * 5 + 2 + 1], *p = str;
+ int i;
+
+ if (user_mode(regs))
+ return;
+
+ for (i = -4; i < 1; i++) {
+ unsigned int val, bad;
+
+ bad = aarch64_insn_read(&((u32 *)addr)[i], &val);
+
+ if (!bad)
+ p += sprintf(p, i == 0 ? "(%08x) " : "%08x ", val);
+ else {
+ p += sprintf(p, "bad PC value");
+ break;
+ }
+ }
+
+ printk("%sCode: %s\n", lvl, str);
+}
+
+#ifdef CONFIG_PREEMPT
+#define S_PREEMPT " PREEMPT"
+#elif defined(CONFIG_PREEMPT_RT)
+#define S_PREEMPT " PREEMPT_RT"
+#else
+#define S_PREEMPT ""
+#endif
+
+#define S_SMP " SMP"
+
+static int __die(const char *str, long err, struct pt_regs *regs)
+{
+ static int die_counter;
+ int ret;
+
+ pr_emerg("Internal error: %s: %016lx [#%d]" S_PREEMPT S_SMP "\n",
+ str, err, ++die_counter);
+
+ /* trap and error numbers are mostly meaningless on ARM */
+ ret = notify_die(DIE_OOPS, str, regs, err, 0, SIGSEGV);
+ if (ret == NOTIFY_STOP)
+ return ret;
+
+ print_modules();
+ show_regs(regs);
+
+ dump_kernel_instr(KERN_EMERG, regs);
+
+ return ret;
+}
+
+static DEFINE_RAW_SPINLOCK(die_lock);
+
+/*
+ * This function is protected against re-entrancy.
+ */
+void die(const char *str, struct pt_regs *regs, long err)
+{
+ int ret;
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&die_lock, flags);
+
+ oops_enter();
+
+ console_verbose();
+ bust_spinlocks(1);
+ ret = __die(str, err, regs);
+
+ if (regs && kexec_should_crash(current))
+ crash_kexec(regs);
+
+ bust_spinlocks(0);
+ add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
+ oops_exit();
+
+ if (in_interrupt())
+ panic("%s: Fatal exception in interrupt", str);
+ if (panic_on_oops)
+ panic("%s: Fatal exception", str);
+
+ raw_spin_unlock_irqrestore(&die_lock, flags);
+
+ if (ret != NOTIFY_STOP)
+ make_task_dead(SIGSEGV);
+}
+
+static void arm64_show_signal(int signo, const char *str)
+{
+ static DEFINE_RATELIMIT_STATE(rs, DEFAULT_RATELIMIT_INTERVAL,
+ DEFAULT_RATELIMIT_BURST);
+ struct task_struct *tsk = current;
+ unsigned long esr = tsk->thread.fault_code;
+ struct pt_regs *regs = task_pt_regs(tsk);
+
+ /* Leave if the signal won't be shown */
+ if (!show_unhandled_signals ||
+ !unhandled_signal(tsk, signo) ||
+ !__ratelimit(&rs))
+ return;
+
+ pr_info("%s[%d]: unhandled exception: ", tsk->comm, task_pid_nr(tsk));
+ if (esr)
+ pr_cont("%s, ESR 0x%016lx, ", esr_get_class_string(esr), esr);
+
+ pr_cont("%s", str);
+ print_vma_addr(KERN_CONT " in ", regs->pc);
+ pr_cont("\n");
+ __show_regs(regs);
+}
+
+void arm64_force_sig_fault(int signo, int code, unsigned long far,
+ const char *str)
+{
+ arm64_show_signal(signo, str);
+ if (signo == SIGKILL)
+ force_sig(SIGKILL);
+ else
+ force_sig_fault(signo, code, (void __user *)far);
+}
+
+void arm64_force_sig_mceerr(int code, unsigned long far, short lsb,
+ const char *str)
+{
+ arm64_show_signal(SIGBUS, str);
+ force_sig_mceerr(code, (void __user *)far, lsb);
+}
+
+void arm64_force_sig_ptrace_errno_trap(int errno, unsigned long far,
+ const char *str)
+{
+ arm64_show_signal(SIGTRAP, str);
+ force_sig_ptrace_errno_trap(errno, (void __user *)far);
+}
+
+void arm64_notify_die(const char *str, struct pt_regs *regs,
+ int signo, int sicode, unsigned long far,
+ unsigned long err)
+{
+ if (user_mode(regs)) {
+ WARN_ON(regs != current_pt_regs());
+ current->thread.fault_address = 0;
+ current->thread.fault_code = err;
+
+ arm64_force_sig_fault(signo, sicode, far, str);
+ } else {
+ die(str, regs, err);
+ }
+}
+
+#ifdef CONFIG_COMPAT
+#define PSTATE_IT_1_0_SHIFT 25
+#define PSTATE_IT_1_0_MASK (0x3 << PSTATE_IT_1_0_SHIFT)
+#define PSTATE_IT_7_2_SHIFT 10
+#define PSTATE_IT_7_2_MASK (0x3f << PSTATE_IT_7_2_SHIFT)
+
+static u32 compat_get_it_state(struct pt_regs *regs)
+{
+ u32 it, pstate = regs->pstate;
+
+ it = (pstate & PSTATE_IT_1_0_MASK) >> PSTATE_IT_1_0_SHIFT;
+ it |= ((pstate & PSTATE_IT_7_2_MASK) >> PSTATE_IT_7_2_SHIFT) << 2;
+
+ return it;
+}
+
+static void compat_set_it_state(struct pt_regs *regs, u32 it)
+{
+ u32 pstate_it;
+
+ pstate_it = (it << PSTATE_IT_1_0_SHIFT) & PSTATE_IT_1_0_MASK;
+ pstate_it |= ((it >> 2) << PSTATE_IT_7_2_SHIFT) & PSTATE_IT_7_2_MASK;
+
+ regs->pstate &= ~PSR_AA32_IT_MASK;
+ regs->pstate |= pstate_it;
+}
+
+static void advance_itstate(struct pt_regs *regs)
+{
+ u32 it;
+
+ /* ARM mode */
+ if (!(regs->pstate & PSR_AA32_T_BIT) ||
+ !(regs->pstate & PSR_AA32_IT_MASK))
+ return;
+
+ it = compat_get_it_state(regs);
+
+ /*
+ * If this is the last instruction of the block, wipe the IT
+ * state. Otherwise advance it.
+ */
+ if (!(it & 7))
+ it = 0;
+ else
+ it = (it & 0xe0) | ((it << 1) & 0x1f);
+
+ compat_set_it_state(regs, it);
+}
+#else
+static void advance_itstate(struct pt_regs *regs)
+{
+}
+#endif
+
+void arm64_skip_faulting_instruction(struct pt_regs *regs, unsigned long size)
+{
+ regs->pc += size;
+
+ /*
+ * If we were single stepping, we want to get the step exception after
+ * we return from the trap.
+ */
+ if (user_mode(regs))
+ user_fastforward_single_step(current);
+
+ if (compat_user_mode(regs))
+ advance_itstate(regs);
+ else
+ regs->pstate &= ~PSR_BTYPE_MASK;
+}
+
+static LIST_HEAD(undef_hook);
+static DEFINE_RAW_SPINLOCK(undef_lock);
+
+void register_undef_hook(struct undef_hook *hook)
+{
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&undef_lock, flags);
+ list_add(&hook->node, &undef_hook);
+ raw_spin_unlock_irqrestore(&undef_lock, flags);
+}
+
+void unregister_undef_hook(struct undef_hook *hook)
+{
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&undef_lock, flags);
+ list_del(&hook->node);
+ raw_spin_unlock_irqrestore(&undef_lock, flags);
+}
+
+static int call_undef_hook(struct pt_regs *regs)
+{
+ struct undef_hook *hook;
+ unsigned long flags;
+ u32 instr;
+ int (*fn)(struct pt_regs *regs, u32 instr) = NULL;
+ unsigned long pc = instruction_pointer(regs);
+
+ if (!user_mode(regs)) {
+ __le32 instr_le;
+ if (get_kernel_nofault(instr_le, (__le32 *)pc))
+ goto exit;
+ instr = le32_to_cpu(instr_le);
+ } else if (compat_thumb_mode(regs)) {
+ /* 16-bit Thumb instruction */
+ __le16 instr_le;
+ if (get_user(instr_le, (__le16 __user *)pc))
+ goto exit;
+ instr = le16_to_cpu(instr_le);
+ if (aarch32_insn_is_wide(instr)) {
+ u32 instr2;
+
+ if (get_user(instr_le, (__le16 __user *)(pc + 2)))
+ goto exit;
+ instr2 = le16_to_cpu(instr_le);
+ instr = (instr << 16) | instr2;
+ }
+ } else {
+ /* 32-bit ARM instruction */
+ __le32 instr_le;
+ if (get_user(instr_le, (__le32 __user *)pc))
+ goto exit;
+ instr = le32_to_cpu(instr_le);
+ }
+
+ raw_spin_lock_irqsave(&undef_lock, flags);
+ list_for_each_entry(hook, &undef_hook, node)
+ if ((instr & hook->instr_mask) == hook->instr_val &&
+ (regs->pstate & hook->pstate_mask) == hook->pstate_val)
+ fn = hook->fn;
+
+ raw_spin_unlock_irqrestore(&undef_lock, flags);
+exit:
+ return fn ? fn(regs, instr) : 1;
+}
+
+void force_signal_inject(int signal, int code, unsigned long address, unsigned long err)
+{
+ const char *desc;
+ struct pt_regs *regs = current_pt_regs();
+
+ if (WARN_ON(!user_mode(regs)))
+ return;
+
+ switch (signal) {
+ case SIGILL:
+ desc = "undefined instruction";
+ break;
+ case SIGSEGV:
+ desc = "illegal memory access";
+ break;
+ default:
+ desc = "unknown or unrecoverable error";
+ break;
+ }
+
+ /* Force signals we don't understand to SIGKILL */
+ if (WARN_ON(signal != SIGKILL &&
+ siginfo_layout(signal, code) != SIL_FAULT)) {
+ signal = SIGKILL;
+ }
+
+ arm64_notify_die(desc, regs, signal, code, address, err);
+}
+
+/*
+ * Set up process info to signal segmentation fault - called on access error.
+ */
+void arm64_notify_segfault(unsigned long addr)
+{
+ int code;
+
+ mmap_read_lock(current->mm);
+ if (find_vma(current->mm, untagged_addr(addr)) == NULL)
+ code = SEGV_MAPERR;
+ else
+ code = SEGV_ACCERR;
+ mmap_read_unlock(current->mm);
+
+ force_signal_inject(SIGSEGV, code, addr, 0);
+}
+
+void do_undefinstr(struct pt_regs *regs, unsigned long esr)
+{
+ /* check for AArch32 breakpoint instructions */
+ if (!aarch32_break_handler(regs))
+ return;
+
+ if (call_undef_hook(regs) == 0)
+ return;
+
+ if (!user_mode(regs))
+ die("Oops - Undefined instruction", regs, esr);
+
+ force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc, 0);
+}
+NOKPROBE_SYMBOL(do_undefinstr);
+
+void do_el0_bti(struct pt_regs *regs)
+{
+ force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc, 0);
+}
+
+void do_el1_bti(struct pt_regs *regs, unsigned long esr)
+{
+ die("Oops - BTI", regs, esr);
+}
+NOKPROBE_SYMBOL(do_el1_bti);
+
+void do_el0_fpac(struct pt_regs *regs, unsigned long esr)
+{
+ force_signal_inject(SIGILL, ILL_ILLOPN, regs->pc, esr);
+}
+
+void do_el1_fpac(struct pt_regs *regs, unsigned long esr)
+{
+ /*
+ * Unexpected FPAC exception in the kernel: kill the task before it
+ * does any more harm.
+ */
+ die("Oops - FPAC", regs, esr);
+}
+NOKPROBE_SYMBOL(do_el1_fpac)
+
+#define __user_cache_maint(insn, address, res) \
+ if (address >= TASK_SIZE_MAX) { \
+ res = -EFAULT; \
+ } else { \
+ uaccess_ttbr0_enable(); \
+ asm volatile ( \
+ "1: " insn ", %1\n" \
+ " mov %w0, #0\n" \
+ "2:\n" \
+ _ASM_EXTABLE_UACCESS_ERR(1b, 2b, %w0) \
+ : "=r" (res) \
+ : "r" (address)); \
+ uaccess_ttbr0_disable(); \
+ }
+
+static void user_cache_maint_handler(unsigned long esr, struct pt_regs *regs)
+{
+ unsigned long tagged_address, address;
+ int rt = ESR_ELx_SYS64_ISS_RT(esr);
+ int crm = (esr & ESR_ELx_SYS64_ISS_CRM_MASK) >> ESR_ELx_SYS64_ISS_CRM_SHIFT;
+ int ret = 0;
+
+ tagged_address = pt_regs_read_reg(regs, rt);
+ address = untagged_addr(tagged_address);
+
+ switch (crm) {
+ case ESR_ELx_SYS64_ISS_CRM_DC_CVAU: /* DC CVAU, gets promoted */
+ __user_cache_maint("dc civac", address, ret);
+ break;
+ case ESR_ELx_SYS64_ISS_CRM_DC_CVAC: /* DC CVAC, gets promoted */
+ __user_cache_maint("dc civac", address, ret);
+ break;
+ case ESR_ELx_SYS64_ISS_CRM_DC_CVADP: /* DC CVADP */
+ __user_cache_maint("sys 3, c7, c13, 1", address, ret);
+ break;
+ case ESR_ELx_SYS64_ISS_CRM_DC_CVAP: /* DC CVAP */
+ __user_cache_maint("sys 3, c7, c12, 1", address, ret);
+ break;
+ case ESR_ELx_SYS64_ISS_CRM_DC_CIVAC: /* DC CIVAC */
+ __user_cache_maint("dc civac", address, ret);
+ break;
+ case ESR_ELx_SYS64_ISS_CRM_IC_IVAU: /* IC IVAU */
+ __user_cache_maint("ic ivau", address, ret);
+ break;
+ default:
+ force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc, 0);
+ return;
+ }
+
+ if (ret)
+ arm64_notify_segfault(tagged_address);
+ else
+ arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
+}
+
+static void ctr_read_handler(unsigned long esr, struct pt_regs *regs)
+{
+ int rt = ESR_ELx_SYS64_ISS_RT(esr);
+ unsigned long val = arm64_ftr_reg_user_value(&arm64_ftr_reg_ctrel0);
+
+ if (cpus_have_const_cap(ARM64_WORKAROUND_1542419)) {
+ /* Hide DIC so that we can trap the unnecessary maintenance...*/
+ val &= ~BIT(CTR_EL0_DIC_SHIFT);
+
+ /* ... and fake IminLine to reduce the number of traps. */
+ val &= ~CTR_EL0_IminLine_MASK;
+ val |= (PAGE_SHIFT - 2) & CTR_EL0_IminLine_MASK;
+ }
+
+ pt_regs_write_reg(regs, rt, val);
+
+ arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
+}
+
+static void cntvct_read_handler(unsigned long esr, struct pt_regs *regs)
+{
+ int rt = ESR_ELx_SYS64_ISS_RT(esr);
+
+ pt_regs_write_reg(regs, rt, arch_timer_read_counter());
+ arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
+}
+
+static void cntfrq_read_handler(unsigned long esr, struct pt_regs *regs)
+{
+ int rt = ESR_ELx_SYS64_ISS_RT(esr);
+
+ pt_regs_write_reg(regs, rt, arch_timer_get_rate());
+ arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
+}
+
+static void mrs_handler(unsigned long esr, struct pt_regs *regs)
+{
+ u32 sysreg, rt;
+
+ rt = ESR_ELx_SYS64_ISS_RT(esr);
+ sysreg = esr_sys64_to_sysreg(esr);
+
+ if (do_emulate_mrs(regs, sysreg, rt) != 0)
+ force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc, 0);
+}
+
+static void wfi_handler(unsigned long esr, struct pt_regs *regs)
+{
+ arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
+}
+
+struct sys64_hook {
+ unsigned long esr_mask;
+ unsigned long esr_val;
+ void (*handler)(unsigned long esr, struct pt_regs *regs);
+};
+
+static const struct sys64_hook sys64_hooks[] = {
+ {
+ .esr_mask = ESR_ELx_SYS64_ISS_EL0_CACHE_OP_MASK,
+ .esr_val = ESR_ELx_SYS64_ISS_EL0_CACHE_OP_VAL,
+ .handler = user_cache_maint_handler,
+ },
+ {
+ /* Trap read access to CTR_EL0 */
+ .esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK,
+ .esr_val = ESR_ELx_SYS64_ISS_SYS_CTR_READ,
+ .handler = ctr_read_handler,
+ },
+ {
+ /* Trap read access to CNTVCT_EL0 */
+ .esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK,
+ .esr_val = ESR_ELx_SYS64_ISS_SYS_CNTVCT,
+ .handler = cntvct_read_handler,
+ },
+ {
+ /* Trap read access to CNTVCTSS_EL0 */
+ .esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK,
+ .esr_val = ESR_ELx_SYS64_ISS_SYS_CNTVCTSS,
+ .handler = cntvct_read_handler,
+ },
+ {
+ /* Trap read access to CNTFRQ_EL0 */
+ .esr_mask = ESR_ELx_SYS64_ISS_SYS_OP_MASK,
+ .esr_val = ESR_ELx_SYS64_ISS_SYS_CNTFRQ,
+ .handler = cntfrq_read_handler,
+ },
+ {
+ /* Trap read access to CPUID registers */
+ .esr_mask = ESR_ELx_SYS64_ISS_SYS_MRS_OP_MASK,
+ .esr_val = ESR_ELx_SYS64_ISS_SYS_MRS_OP_VAL,
+ .handler = mrs_handler,
+ },
+ {
+ /* Trap WFI instructions executed in userspace */
+ .esr_mask = ESR_ELx_WFx_MASK,
+ .esr_val = ESR_ELx_WFx_WFI_VAL,
+ .handler = wfi_handler,
+ },
+ {},
+};
+
+#ifdef CONFIG_COMPAT
+static bool cp15_cond_valid(unsigned long esr, struct pt_regs *regs)
+{
+ int cond;
+
+ /* Only a T32 instruction can trap without CV being set */
+ if (!(esr & ESR_ELx_CV)) {
+ u32 it;
+
+ it = compat_get_it_state(regs);
+ if (!it)
+ return true;
+
+ cond = it >> 4;
+ } else {
+ cond = (esr & ESR_ELx_COND_MASK) >> ESR_ELx_COND_SHIFT;
+ }
+
+ return aarch32_opcode_cond_checks[cond](regs->pstate);
+}
+
+static void compat_cntfrq_read_handler(unsigned long esr, struct pt_regs *regs)
+{
+ int reg = (esr & ESR_ELx_CP15_32_ISS_RT_MASK) >> ESR_ELx_CP15_32_ISS_RT_SHIFT;
+
+ pt_regs_write_reg(regs, reg, arch_timer_get_rate());
+ arm64_skip_faulting_instruction(regs, 4);
+}
+
+static const struct sys64_hook cp15_32_hooks[] = {
+ {
+ .esr_mask = ESR_ELx_CP15_32_ISS_SYS_MASK,
+ .esr_val = ESR_ELx_CP15_32_ISS_SYS_CNTFRQ,
+ .handler = compat_cntfrq_read_handler,
+ },
+ {},
+};
+
+static void compat_cntvct_read_handler(unsigned long esr, struct pt_regs *regs)
+{
+ int rt = (esr & ESR_ELx_CP15_64_ISS_RT_MASK) >> ESR_ELx_CP15_64_ISS_RT_SHIFT;
+ int rt2 = (esr & ESR_ELx_CP15_64_ISS_RT2_MASK) >> ESR_ELx_CP15_64_ISS_RT2_SHIFT;
+ u64 val = arch_timer_read_counter();
+
+ pt_regs_write_reg(regs, rt, lower_32_bits(val));
+ pt_regs_write_reg(regs, rt2, upper_32_bits(val));
+ arm64_skip_faulting_instruction(regs, 4);
+}
+
+static const struct sys64_hook cp15_64_hooks[] = {
+ {
+ .esr_mask = ESR_ELx_CP15_64_ISS_SYS_MASK,
+ .esr_val = ESR_ELx_CP15_64_ISS_SYS_CNTVCT,
+ .handler = compat_cntvct_read_handler,
+ },
+ {
+ .esr_mask = ESR_ELx_CP15_64_ISS_SYS_MASK,
+ .esr_val = ESR_ELx_CP15_64_ISS_SYS_CNTVCTSS,
+ .handler = compat_cntvct_read_handler,
+ },
+ {},
+};
+
+void do_cp15instr(unsigned long esr, struct pt_regs *regs)
+{
+ const struct sys64_hook *hook, *hook_base;
+
+ if (!cp15_cond_valid(esr, regs)) {
+ /*
+ * There is no T16 variant of a CP access, so we
+ * always advance PC by 4 bytes.
+ */
+ arm64_skip_faulting_instruction(regs, 4);
+ return;
+ }
+
+ switch (ESR_ELx_EC(esr)) {
+ case ESR_ELx_EC_CP15_32:
+ hook_base = cp15_32_hooks;
+ break;
+ case ESR_ELx_EC_CP15_64:
+ hook_base = cp15_64_hooks;
+ break;
+ default:
+ do_undefinstr(regs, esr);
+ return;
+ }
+
+ for (hook = hook_base; hook->handler; hook++)
+ if ((hook->esr_mask & esr) == hook->esr_val) {
+ hook->handler(esr, regs);
+ return;
+ }
+
+ /*
+ * New cp15 instructions may previously have been undefined at
+ * EL0. Fall back to our usual undefined instruction handler
+ * so that we handle these consistently.
+ */
+ do_undefinstr(regs, esr);
+}
+NOKPROBE_SYMBOL(do_cp15instr);
+#endif
+
+void do_sysinstr(unsigned long esr, struct pt_regs *regs)
+{
+ const struct sys64_hook *hook;
+
+ for (hook = sys64_hooks; hook->handler; hook++)
+ if ((hook->esr_mask & esr) == hook->esr_val) {
+ hook->handler(esr, regs);
+ return;
+ }
+
+ /*
+ * New SYS instructions may previously have been undefined at EL0. Fall
+ * back to our usual undefined instruction handler so that we handle
+ * these consistently.
+ */
+ do_undefinstr(regs, esr);
+}
+NOKPROBE_SYMBOL(do_sysinstr);
+
+static const char *esr_class_str[] = {
+ [0 ... ESR_ELx_EC_MAX] = "UNRECOGNIZED EC",
+ [ESR_ELx_EC_UNKNOWN] = "Unknown/Uncategorized",
+ [ESR_ELx_EC_WFx] = "WFI/WFE",
+ [ESR_ELx_EC_CP15_32] = "CP15 MCR/MRC",
+ [ESR_ELx_EC_CP15_64] = "CP15 MCRR/MRRC",
+ [ESR_ELx_EC_CP14_MR] = "CP14 MCR/MRC",
+ [ESR_ELx_EC_CP14_LS] = "CP14 LDC/STC",
+ [ESR_ELx_EC_FP_ASIMD] = "ASIMD",
+ [ESR_ELx_EC_CP10_ID] = "CP10 MRC/VMRS",
+ [ESR_ELx_EC_PAC] = "PAC",
+ [ESR_ELx_EC_CP14_64] = "CP14 MCRR/MRRC",
+ [ESR_ELx_EC_BTI] = "BTI",
+ [ESR_ELx_EC_ILL] = "PSTATE.IL",
+ [ESR_ELx_EC_SVC32] = "SVC (AArch32)",
+ [ESR_ELx_EC_HVC32] = "HVC (AArch32)",
+ [ESR_ELx_EC_SMC32] = "SMC (AArch32)",
+ [ESR_ELx_EC_SVC64] = "SVC (AArch64)",
+ [ESR_ELx_EC_HVC64] = "HVC (AArch64)",
+ [ESR_ELx_EC_SMC64] = "SMC (AArch64)",
+ [ESR_ELx_EC_SYS64] = "MSR/MRS (AArch64)",
+ [ESR_ELx_EC_SVE] = "SVE",
+ [ESR_ELx_EC_ERET] = "ERET/ERETAA/ERETAB",
+ [ESR_ELx_EC_FPAC] = "FPAC",
+ [ESR_ELx_EC_SME] = "SME",
+ [ESR_ELx_EC_IMP_DEF] = "EL3 IMP DEF",
+ [ESR_ELx_EC_IABT_LOW] = "IABT (lower EL)",
+ [ESR_ELx_EC_IABT_CUR] = "IABT (current EL)",
+ [ESR_ELx_EC_PC_ALIGN] = "PC Alignment",
+ [ESR_ELx_EC_DABT_LOW] = "DABT (lower EL)",
+ [ESR_ELx_EC_DABT_CUR] = "DABT (current EL)",
+ [ESR_ELx_EC_SP_ALIGN] = "SP Alignment",
+ [ESR_ELx_EC_FP_EXC32] = "FP (AArch32)",
+ [ESR_ELx_EC_FP_EXC64] = "FP (AArch64)",
+ [ESR_ELx_EC_SERROR] = "SError",
+ [ESR_ELx_EC_BREAKPT_LOW] = "Breakpoint (lower EL)",
+ [ESR_ELx_EC_BREAKPT_CUR] = "Breakpoint (current EL)",
+ [ESR_ELx_EC_SOFTSTP_LOW] = "Software Step (lower EL)",
+ [ESR_ELx_EC_SOFTSTP_CUR] = "Software Step (current EL)",
+ [ESR_ELx_EC_WATCHPT_LOW] = "Watchpoint (lower EL)",
+ [ESR_ELx_EC_WATCHPT_CUR] = "Watchpoint (current EL)",
+ [ESR_ELx_EC_BKPT32] = "BKPT (AArch32)",
+ [ESR_ELx_EC_VECTOR32] = "Vector catch (AArch32)",
+ [ESR_ELx_EC_BRK64] = "BRK (AArch64)",
+};
+
+const char *esr_get_class_string(unsigned long esr)
+{
+ return esr_class_str[ESR_ELx_EC(esr)];
+}
+
+/*
+ * bad_el0_sync handles unexpected, but potentially recoverable synchronous
+ * exceptions taken from EL0.
+ */
+void bad_el0_sync(struct pt_regs *regs, int reason, unsigned long esr)
+{
+ unsigned long pc = instruction_pointer(regs);
+
+ current->thread.fault_address = 0;
+ current->thread.fault_code = esr;
+
+ arm64_force_sig_fault(SIGILL, ILL_ILLOPC, pc,
+ "Bad EL0 synchronous exception");
+}
+
+#ifdef CONFIG_VMAP_STACK
+
+DEFINE_PER_CPU(unsigned long [OVERFLOW_STACK_SIZE/sizeof(long)], overflow_stack)
+ __aligned(16);
+
+void panic_bad_stack(struct pt_regs *regs, unsigned long esr, unsigned long far)
+{
+ unsigned long tsk_stk = (unsigned long)current->stack;
+ unsigned long irq_stk = (unsigned long)this_cpu_read(irq_stack_ptr);
+ unsigned long ovf_stk = (unsigned long)this_cpu_ptr(overflow_stack);
+
+ console_verbose();
+ pr_emerg("Insufficient stack space to handle exception!");
+
+ pr_emerg("ESR: 0x%016lx -- %s\n", esr, esr_get_class_string(esr));
+ pr_emerg("FAR: 0x%016lx\n", far);
+
+ pr_emerg("Task stack: [0x%016lx..0x%016lx]\n",
+ tsk_stk, tsk_stk + THREAD_SIZE);
+ pr_emerg("IRQ stack: [0x%016lx..0x%016lx]\n",
+ irq_stk, irq_stk + IRQ_STACK_SIZE);
+ pr_emerg("Overflow stack: [0x%016lx..0x%016lx]\n",
+ ovf_stk, ovf_stk + OVERFLOW_STACK_SIZE);
+
+ __show_regs(regs);
+
+ /*
+ * We use nmi_panic to limit the potential for recusive overflows, and
+ * to get a better stack trace.
+ */
+ nmi_panic(NULL, "kernel stack overflow");
+ cpu_park_loop();
+}
+#endif
+
+void __noreturn arm64_serror_panic(struct pt_regs *regs, unsigned long esr)
+{
+ console_verbose();
+
+ pr_crit("SError Interrupt on CPU%d, code 0x%016lx -- %s\n",
+ smp_processor_id(), esr, esr_get_class_string(esr));
+ if (regs)
+ __show_regs(regs);
+
+ nmi_panic(regs, "Asynchronous SError Interrupt");
+
+ cpu_park_loop();
+ unreachable();
+}
+
+bool arm64_is_fatal_ras_serror(struct pt_regs *regs, unsigned long esr)
+{
+ unsigned long aet = arm64_ras_serror_get_severity(esr);
+
+ switch (aet) {
+ case ESR_ELx_AET_CE: /* corrected error */
+ case ESR_ELx_AET_UEO: /* restartable, not yet consumed */
+ /*
+ * The CPU can make progress. We may take UEO again as
+ * a more severe error.
+ */
+ return false;
+
+ case ESR_ELx_AET_UEU: /* Uncorrected Unrecoverable */
+ case ESR_ELx_AET_UER: /* Uncorrected Recoverable */
+ /*
+ * The CPU can't make progress. The exception may have
+ * been imprecise.
+ *
+ * Neoverse-N1 #1349291 means a non-KVM SError reported as
+ * Unrecoverable should be treated as Uncontainable. We
+ * call arm64_serror_panic() in both cases.
+ */
+ return true;
+
+ case ESR_ELx_AET_UC: /* Uncontainable or Uncategorized error */
+ default:
+ /* Error has been silently propagated */
+ arm64_serror_panic(regs, esr);
+ }
+}
+
+void do_serror(struct pt_regs *regs, unsigned long esr)
+{
+ /* non-RAS errors are not containable */
+ if (!arm64_is_ras_serror(esr) || arm64_is_fatal_ras_serror(regs, esr))
+ arm64_serror_panic(regs, esr);
+}
+
+/* GENERIC_BUG traps */
+
+int is_valid_bugaddr(unsigned long addr)
+{
+ /*
+ * bug_handler() only called for BRK #BUG_BRK_IMM.
+ * So the answer is trivial -- any spurious instances with no
+ * bug table entry will be rejected by report_bug() and passed
+ * back to the debug-monitors code and handled as a fatal
+ * unexpected debug exception.
+ */
+ return 1;
+}
+
+static int bug_handler(struct pt_regs *regs, unsigned long esr)
+{
+ switch (report_bug(regs->pc, regs)) {
+ case BUG_TRAP_TYPE_BUG:
+ die("Oops - BUG", regs, esr);
+ break;
+
+ case BUG_TRAP_TYPE_WARN:
+ break;
+
+ default:
+ /* unknown/unrecognised bug trap type */
+ return DBG_HOOK_ERROR;
+ }
+
+ /* If thread survives, skip over the BUG instruction and continue: */
+ arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
+ return DBG_HOOK_HANDLED;
+}
+
+static struct break_hook bug_break_hook = {
+ .fn = bug_handler,
+ .imm = BUG_BRK_IMM,
+};
+
+#ifdef CONFIG_CFI_CLANG
+static int cfi_handler(struct pt_regs *regs, unsigned long esr)
+{
+ unsigned long target;
+ u32 type;
+
+ target = pt_regs_read_reg(regs, FIELD_GET(CFI_BRK_IMM_TARGET, esr));
+ type = (u32)pt_regs_read_reg(regs, FIELD_GET(CFI_BRK_IMM_TYPE, esr));
+
+ switch (report_cfi_failure(regs, regs->pc, &target, type)) {
+ case BUG_TRAP_TYPE_BUG:
+ die("Oops - CFI", regs, 0);
+ break;
+
+ case BUG_TRAP_TYPE_WARN:
+ break;
+
+ default:
+ return DBG_HOOK_ERROR;
+ }
+
+ arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
+ return DBG_HOOK_HANDLED;
+}
+
+static struct break_hook cfi_break_hook = {
+ .fn = cfi_handler,
+ .imm = CFI_BRK_IMM_BASE,
+ .mask = CFI_BRK_IMM_MASK,
+};
+#endif /* CONFIG_CFI_CLANG */
+
+static int reserved_fault_handler(struct pt_regs *regs, unsigned long esr)
+{
+ pr_err("%s generated an invalid instruction at %pS!\n",
+ "Kernel text patching",
+ (void *)instruction_pointer(regs));
+
+ /* We cannot handle this */
+ return DBG_HOOK_ERROR;
+}
+
+static struct break_hook fault_break_hook = {
+ .fn = reserved_fault_handler,
+ .imm = FAULT_BRK_IMM,
+};
+
+#ifdef CONFIG_KASAN_SW_TAGS
+
+#define KASAN_ESR_RECOVER 0x20
+#define KASAN_ESR_WRITE 0x10
+#define KASAN_ESR_SIZE_MASK 0x0f
+#define KASAN_ESR_SIZE(esr) (1 << ((esr) & KASAN_ESR_SIZE_MASK))
+
+static int kasan_handler(struct pt_regs *regs, unsigned long esr)
+{
+ bool recover = esr & KASAN_ESR_RECOVER;
+ bool write = esr & KASAN_ESR_WRITE;
+ size_t size = KASAN_ESR_SIZE(esr);
+ u64 addr = regs->regs[0];
+ u64 pc = regs->pc;
+
+ kasan_report(addr, size, write, pc);
+
+ /*
+ * The instrumentation allows to control whether we can proceed after
+ * a crash was detected. This is done by passing the -recover flag to
+ * the compiler. Disabling recovery allows to generate more compact
+ * code.
+ *
+ * Unfortunately disabling recovery doesn't work for the kernel right
+ * now. KASAN reporting is disabled in some contexts (for example when
+ * the allocator accesses slab object metadata; this is controlled by
+ * current->kasan_depth). All these accesses are detected by the tool,
+ * even though the reports for them are not printed.
+ *
+ * This is something that might be fixed at some point in the future.
+ */
+ if (!recover)
+ die("Oops - KASAN", regs, esr);
+
+ /* If thread survives, skip over the brk instruction and continue: */
+ arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
+ return DBG_HOOK_HANDLED;
+}
+
+static struct break_hook kasan_break_hook = {
+ .fn = kasan_handler,
+ .imm = KASAN_BRK_IMM,
+ .mask = KASAN_BRK_MASK,
+};
+#endif
+
+
+#define esr_comment(esr) ((esr) & ESR_ELx_BRK64_ISS_COMMENT_MASK)
+
+/*
+ * Initial handler for AArch64 BRK exceptions
+ * This handler only used until debug_traps_init().
+ */
+int __init early_brk64(unsigned long addr, unsigned long esr,
+ struct pt_regs *regs)
+{
+#ifdef CONFIG_CFI_CLANG
+ if ((esr_comment(esr) & ~CFI_BRK_IMM_MASK) == CFI_BRK_IMM_BASE)
+ return cfi_handler(regs, esr) != DBG_HOOK_HANDLED;
+#endif
+#ifdef CONFIG_KASAN_SW_TAGS
+ if ((esr_comment(esr) & ~KASAN_BRK_MASK) == KASAN_BRK_IMM)
+ return kasan_handler(regs, esr) != DBG_HOOK_HANDLED;
+#endif
+ return bug_handler(regs, esr) != DBG_HOOK_HANDLED;
+}
+
+void __init trap_init(void)
+{
+ register_kernel_break_hook(&bug_break_hook);
+#ifdef CONFIG_CFI_CLANG
+ register_kernel_break_hook(&cfi_break_hook);
+#endif
+ register_kernel_break_hook(&fault_break_hook);
+#ifdef CONFIG_KASAN_SW_TAGS
+ register_kernel_break_hook(&kasan_break_hook);
+#endif
+ debug_traps_init();
+}