1 files changed, 265 insertions, 67 deletions

diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
index eb2d15147e8d..5f4d9acb32f5 100644
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -38,6 +38,7 @@
 
 #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>
@@ -223,13 +224,61 @@ void die(const char *str, struct pt_regs *regs, int err)
 		do_exit(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 int 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%08x, ", 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, void __user *addr,
+			   const char *str)
+{
+	arm64_show_signal(signo, str);
+	force_sig_fault(signo, code, addr, current);
+}
+
+void arm64_force_sig_mceerr(int code, void __user *addr, short lsb,
+			    const char *str)
+{
+	arm64_show_signal(SIGBUS, str);
+	force_sig_mceerr(code, addr, lsb, current);
+}
+
+void arm64_force_sig_ptrace_errno_trap(int errno, void __user *addr,
+				       const char *str)
+{
+	arm64_show_signal(SIGTRAP, str);
+	force_sig_ptrace_errno_trap(errno, addr);
+}
+
 void arm64_notify_die(const char *str, struct pt_regs *regs,
-		      struct siginfo *info, int err)
+		      int signo, int sicode, void __user *addr,
+		      int err)
 {
 	if (user_mode(regs)) {
+		WARN_ON(regs != current_pt_regs());
 		current->thread.fault_address = 0;
 		current->thread.fault_code = err;
-		force_sig_info(info->si_signo, info, current);
+
+		arm64_force_sig_fault(signo, sicode, addr, str);
 	} else {
 		die(str, regs, err);
 	}
@@ -243,7 +292,8 @@ void arm64_skip_faulting_instruction(struct pt_regs *regs, unsigned long size)
 	 * If we were single stepping, we want to get the step exception after
 	 * we return from the trap.
 	 */
-	user_fastforward_single_step(current);
+	if (user_mode(regs))
+		user_fastforward_single_step(current);
 }
 
 static LIST_HEAD(undef_hook);
@@ -275,10 +325,12 @@ static int call_undef_hook(struct pt_regs *regs)
 	int (*fn)(struct pt_regs *regs, u32 instr) = NULL;
 	void __user *pc = (void __user *)instruction_pointer(regs);
 
-	if (!user_mode(regs))
-		return 1;
-
-	if (compat_thumb_mode(regs)) {
+	if (!user_mode(regs)) {
+		__le32 instr_le;
+		if (probe_kernel_address((__force __le32 *)pc, instr_le))
+			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))
@@ -311,12 +363,13 @@ exit:
 	return fn ? fn(regs, instr) : 1;
 }
 
-void force_signal_inject(int signal, int code, struct pt_regs *regs,
-			 unsigned long address)
+void force_signal_inject(int signal, int code, unsigned long address)
 {
-	siginfo_t info;
-	void __user *pc = (void __user *)instruction_pointer(regs);
 	const char *desc;
+	struct pt_regs *regs = current_pt_regs();
+
+	if (WARN_ON(!user_mode(regs)))
+		return;
 
 	switch (signal) {
 	case SIGILL:
@@ -330,25 +383,19 @@ void force_signal_inject(int signal, int code, struct pt_regs *regs,
 		break;
 	}
 
-	if (unhandled_signal(current, signal) &&
-	    show_unhandled_signals_ratelimited()) {
-		pr_info("%s[%d]: %s: pc=%p\n",
-			current->comm, task_pid_nr(current), desc, pc);
-		dump_instr(KERN_INFO, regs);
+	/* Force signals we don't understand to SIGKILL */
+	if (WARN_ON(signal != SIGKILL &&
+		    siginfo_layout(signal, code) != SIL_FAULT)) {
+		signal = SIGKILL;
 	}
 
-	info.si_signo = signal;
-	info.si_errno = 0;
-	info.si_code  = code;
-	info.si_addr  = pc;
-
-	arm64_notify_die(desc, regs, &info, 0);
+	arm64_notify_die(desc, regs, signal, code, (void __user *)address, 0);
 }
 
 /*
  * Set up process info to signal segmentation fault - called on access error.
  */
-void arm64_notify_segfault(struct pt_regs *regs, unsigned long addr)
+void arm64_notify_segfault(unsigned long addr)
 {
 	int code;
 
@@ -359,7 +406,7 @@ void arm64_notify_segfault(struct pt_regs *regs, unsigned long addr)
 		code = SEGV_ACCERR;
 	up_read(&current->mm->mmap_sem);
 
-	force_signal_inject(SIGSEGV, code, regs, addr);
+	force_signal_inject(SIGSEGV, code, addr);
 }
 
 asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
@@ -371,13 +418,8 @@ asmlinkage void __exception do_undefinstr(struct pt_regs *regs)
 	if (call_undef_hook(regs) == 0)
 		return;
 
-	force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
-}
-
-int cpu_enable_cache_maint_trap(void *__unused)
-{
-	config_sctlr_el1(SCTLR_EL1_UCI, 0);
-	return 0;
+	BUG_ON(!user_mode(regs));
+	force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc);
 }
 
 #define __user_cache_maint(insn, address, res)			\
@@ -403,7 +445,7 @@ int cpu_enable_cache_maint_trap(void *__unused)
 static void user_cache_maint_handler(unsigned int esr, struct pt_regs *regs)
 {
 	unsigned long address;
-	int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
+	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;
 
@@ -426,19 +468,19 @@ static void user_cache_maint_handler(unsigned int esr, struct pt_regs *regs)
 		__user_cache_maint("ic ivau", address, ret);
 		break;
 	default:
-		force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
+		force_signal_inject(SIGILL, ILL_ILLOPC, regs->pc);
 		return;
 	}
 
 	if (ret)
-		arm64_notify_segfault(regs, address);
+		arm64_notify_segfault(address);
 	else
 		arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
 }
 
 static void ctr_read_handler(unsigned int esr, struct pt_regs *regs)
 {
-	int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
+	int rt = ESR_ELx_SYS64_ISS_RT(esr);
 	unsigned long val = arm64_ftr_reg_user_value(&arm64_ftr_reg_ctrel0);
 
 	pt_regs_write_reg(regs, rt, val);
@@ -448,7 +490,7 @@ static void ctr_read_handler(unsigned int esr, struct pt_regs *regs)
 
 static void cntvct_read_handler(unsigned int esr, struct pt_regs *regs)
 {
-	int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
+	int rt = ESR_ELx_SYS64_ISS_RT(esr);
 
 	pt_regs_write_reg(regs, rt, arch_counter_get_cntvct());
 	arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
@@ -456,12 +498,28 @@ static void cntvct_read_handler(unsigned int esr, struct pt_regs *regs)
 
 static void cntfrq_read_handler(unsigned int esr, struct pt_regs *regs)
 {
-	int rt = (esr & ESR_ELx_SYS64_ISS_RT_MASK) >> ESR_ELx_SYS64_ISS_RT_SHIFT;
+	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 int 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);
+}
+
+static void wfi_handler(unsigned int esr, struct pt_regs *regs)
+{
+	arm64_skip_faulting_instruction(regs, AARCH64_INSN_SIZE);
+}
+
 struct sys64_hook {
 	unsigned int esr_mask;
 	unsigned int esr_val;
@@ -492,9 +550,176 @@ static struct sys64_hook sys64_hooks[] = {
 		.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
+#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 bool cp15_cond_valid(unsigned int 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 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);
+}
+
+static void arm64_compat_skip_faulting_instruction(struct pt_regs *regs,
+						   unsigned int sz)
+{
+	advance_itstate(regs);
+	arm64_skip_faulting_instruction(regs, sz);
+}
+
+static void compat_cntfrq_read_handler(unsigned int 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_compat_skip_faulting_instruction(regs, 4);
+}
+
+static 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 int 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_counter_get_cntvct();
+
+	pt_regs_write_reg(regs, rt, lower_32_bits(val));
+	pt_regs_write_reg(regs, rt2, upper_32_bits(val));
+	arm64_compat_skip_faulting_instruction(regs, 4);
+}
+
+static 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,
+	},
+	{},
+};
+
+asmlinkage void __exception do_cp15instr(unsigned int esr, struct pt_regs *regs)
+{
+	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_compat_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);
+		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);
+}
+#endif
+
 asmlinkage void __exception do_sysinstr(unsigned int esr, struct pt_regs *regs)
 {
 	struct sys64_hook *hook;
@@ -513,22 +738,6 @@ asmlinkage void __exception do_sysinstr(unsigned int esr, struct pt_regs *regs)
 	do_undefinstr(regs);
 }
 
-long compat_arm_syscall(struct pt_regs *regs);
-
-asmlinkage long do_ni_syscall(struct pt_regs *regs)
-{
-#ifdef CONFIG_COMPAT
-	long ret;
-	if (is_compat_task()) {
-		ret = compat_arm_syscall(regs);
-		if (ret != -ENOSYS)
-			return ret;
-	}
-#endif
-
-	return sys_ni_syscall();
-}
-
 static const char *esr_class_str[] = {
 	[0 ... ESR_ELx_EC_MAX]		= "UNRECOGNIZED EC",
 	[ESR_ELx_EC_UNKNOWN]		= "Unknown/Uncategorized",
@@ -587,7 +796,6 @@ asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr)
 		handler[reason], smp_processor_id(), esr,
 		esr_get_class_string(esr));
 
-	die("Oops - bad mode", regs, 0);
 	local_daif_mask();
 	panic("bad mode");
 }
@@ -598,23 +806,13 @@ asmlinkage void bad_mode(struct pt_regs *regs, int reason, unsigned int esr)
  */
 asmlinkage void bad_el0_sync(struct pt_regs *regs, int reason, unsigned int esr)
 {
-	siginfo_t info;
 	void __user *pc = (void __user *)instruction_pointer(regs);
-	console_verbose();
-
-	pr_crit("Bad EL0 synchronous exception detected on CPU%d, code 0x%08x -- %s\n",
-		smp_processor_id(), esr, esr_get_class_string(esr));
-	__show_regs(regs);
-
-	info.si_signo = SIGILL;
-	info.si_errno = 0;
-	info.si_code  = ILL_ILLOPC;
-	info.si_addr  = pc;
 
 	current->thread.fault_address = 0;
-	current->thread.fault_code = 0;
+	current->thread.fault_code = esr;
 
-	force_sig_info(info.si_signo, &info, current);
+	arm64_force_sig_fault(SIGILL, ILL_ILLOPC, pc,
+			      "Bad EL0 synchronous exception");
 }
 
 #ifdef CONFIG_VMAP_STACK