Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

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();
+}