1 files changed, 157 insertions, 112 deletions

diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 33984c04b60b..7d5532adc890 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -12,6 +12,7 @@
  * Copyright (C) 2000, 2001, 2012 MIPS Technologies, Inc.  All rights reserved.
  * Copyright (C) 2014, Imagination Technologies Ltd.
  */
+#include <linux/bitops.h>
 #include <linux/bug.h>
 #include <linux/compiler.h>
 #include <linux/context_tracking.h>
@@ -699,29 +700,60 @@ asmlinkage void do_ov(struct pt_regs *regs)
 	exception_exit(prev_state);
 }
 
-int process_fpemu_return(int sig, void __user *fault_addr)
+int process_fpemu_return(int sig, void __user *fault_addr, unsigned long fcr31)
 {
-	if (sig == SIGSEGV || sig == SIGBUS) {
-		struct siginfo si = {0};
+	struct siginfo si = { 0 };
+
+	switch (sig) {
+	case 0:
+		return 0;
+
+	case SIGFPE:
 		si.si_addr = fault_addr;
 		si.si_signo = sig;
-		if (sig == SIGSEGV) {
-			down_read(&current->mm->mmap_sem);
-			if (find_vma(current->mm, (unsigned long)fault_addr))
-				si.si_code = SEGV_ACCERR;
-			else
-				si.si_code = SEGV_MAPERR;
-			up_read(&current->mm->mmap_sem);
-		} else {
-			si.si_code = BUS_ADRERR;
-		}
+		/*
+		 * Inexact can happen together with Overflow or Underflow.
+		 * Respect the mask to deliver the correct exception.
+		 */
+		fcr31 &= (fcr31 & FPU_CSR_ALL_E) <<
+			 (ffs(FPU_CSR_ALL_X) - ffs(FPU_CSR_ALL_E));
+		if (fcr31 & FPU_CSR_INV_X)
+			si.si_code = FPE_FLTINV;
+		else if (fcr31 & FPU_CSR_DIV_X)
+			si.si_code = FPE_FLTDIV;
+		else if (fcr31 & FPU_CSR_OVF_X)
+			si.si_code = FPE_FLTOVF;
+		else if (fcr31 & FPU_CSR_UDF_X)
+			si.si_code = FPE_FLTUND;
+		else if (fcr31 & FPU_CSR_INE_X)
+			si.si_code = FPE_FLTRES;
+		else
+			si.si_code = __SI_FAULT;
+		force_sig_info(sig, &si, current);
+		return 1;
+
+	case SIGBUS:
+		si.si_addr = fault_addr;
+		si.si_signo = sig;
+		si.si_code = BUS_ADRERR;
+		force_sig_info(sig, &si, current);
+		return 1;
+
+	case SIGSEGV:
+		si.si_addr = fault_addr;
+		si.si_signo = sig;
+		down_read(&current->mm->mmap_sem);
+		if (find_vma(current->mm, (unsigned long)fault_addr))
+			si.si_code = SEGV_ACCERR;
+		else
+			si.si_code = SEGV_MAPERR;
+		up_read(&current->mm->mmap_sem);
 		force_sig_info(sig, &si, current);
 		return 1;
-	} else if (sig) {
+
+	default:
 		force_sig(sig, current);
 		return 1;
-	} else {
-		return 0;
 	}
 }
 
@@ -729,7 +761,8 @@ static int simulate_fp(struct pt_regs *regs, unsigned int opcode,
 		       unsigned long old_epc, unsigned long old_ra)
 {
 	union mips_instruction inst = { .word = opcode };
-	void __user *fault_addr = NULL;
+	void __user *fault_addr;
+	unsigned long fcr31;
 	int sig;
 
 	/* If it's obviously not an FP instruction, skip it */
@@ -759,13 +792,20 @@ static int simulate_fp(struct pt_regs *regs, unsigned int opcode,
 	/* Run the emulator */
 	sig = fpu_emulator_cop1Handler(regs, &current->thread.fpu, 1,
 				       &fault_addr);
+	fcr31 = current->thread.fpu.fcr31;
 
-	/* If something went wrong, signal */
-	process_fpemu_return(sig, fault_addr);
+	/*
+	 * We can't allow the emulated instruction to leave any of
+	 * the cause bits set in $fcr31.
+	 */
+	current->thread.fpu.fcr31 &= ~FPU_CSR_ALL_X;
 
 	/* Restore the hardware register state */
 	own_fpu(1);
 
+	/* Send a signal if required.  */
+	process_fpemu_return(sig, fault_addr, fcr31);
+
 	return 0;
 }
 
@@ -775,7 +815,8 @@ static int simulate_fp(struct pt_regs *regs, unsigned int opcode,
 asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
 {
 	enum ctx_state prev_state;
-	siginfo_t info = {0};
+	void __user *fault_addr;
+	int sig;
 
 	prev_state = exception_enter();
 	if (notify_die(DIE_FP, "FP exception", regs, 0, regs_to_trapnr(regs),
@@ -784,9 +825,6 @@ asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
 	die_if_kernel("FP exception in kernel code", regs);
 
 	if (fcr31 & FPU_CSR_UNI_X) {
-		int sig;
-		void __user *fault_addr = NULL;
-
 		/*
 		 * Unimplemented operation exception.  If we've got the full
 		 * software emulator on-board, let's use it...
@@ -803,36 +841,23 @@ asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
 		/* Run the emulator */
 		sig = fpu_emulator_cop1Handler(regs, &current->thread.fpu, 1,
 					       &fault_addr);
+		fcr31 = current->thread.fpu.fcr31;
 
 		/*
 		 * We can't allow the emulated instruction to leave any of
-		 * the cause bit set in $fcr31.
+		 * the cause bits set in $fcr31.
 		 */
 		current->thread.fpu.fcr31 &= ~FPU_CSR_ALL_X;
 
 		/* Restore the hardware register state */
 		own_fpu(1);	/* Using the FPU again.	 */
+	} else {
+		sig = SIGFPE;
+		fault_addr = (void __user *) regs->cp0_epc;
+	}
 
-		/* If something went wrong, signal */
-		process_fpemu_return(sig, fault_addr);
-
-		goto out;
-	} else if (fcr31 & FPU_CSR_INV_X)
-		info.si_code = FPE_FLTINV;
-	else if (fcr31 & FPU_CSR_DIV_X)
-		info.si_code = FPE_FLTDIV;
-	else if (fcr31 & FPU_CSR_OVF_X)
-		info.si_code = FPE_FLTOVF;
-	else if (fcr31 & FPU_CSR_UDF_X)
-		info.si_code = FPE_FLTUND;
-	else if (fcr31 & FPU_CSR_INE_X)
-		info.si_code = FPE_FLTRES;
-	else
-		info.si_code = __SI_FAULT;
-	info.si_signo = SIGFPE;
-	info.si_errno = 0;
-	info.si_addr = (void __user *) regs->cp0_epc;
-	force_sig_info(SIGFPE, &info, current);
+	/* Send a signal if required.  */
+	process_fpemu_return(sig, fault_addr, fcr31);
 
 out:
 	exception_exit(prev_state);
@@ -879,9 +904,9 @@ void do_trap_or_bp(struct pt_regs *regs, unsigned int code,
 		break;
 	case BRK_MEMU:
 		/*
-		 * Address errors may be deliberately induced by the FPU
-		 * emulator to retake control of the CPU after executing the
-		 * instruction in the delay slot of an emulated branch.
+		 * This breakpoint code is used by the FPU emulator to retake
+		 * control of the CPU after executing the instruction from the
+		 * delay slot of an emulated branch.
 		 *
 		 * Terminate if exception was recognized as a delay slot return
 		 * otherwise handle as normal.
@@ -901,10 +926,9 @@ void do_trap_or_bp(struct pt_regs *regs, unsigned int code,
 
 asmlinkage void do_bp(struct pt_regs *regs)
 {
+	unsigned long epc = msk_isa16_mode(exception_epc(regs));
 	unsigned int opcode, bcode;
 	enum ctx_state prev_state;
-	unsigned long epc;
-	u16 instr[2];
 	mm_segment_t seg;
 
 	seg = get_fs();
@@ -913,26 +937,28 @@ asmlinkage void do_bp(struct pt_regs *regs)
 
 	prev_state = exception_enter();
 	if (get_isa16_mode(regs->cp0_epc)) {
-		/* Calculate EPC. */
-		epc = exception_epc(regs);
-		if (cpu_has_mmips) {
-			if ((__get_user(instr[0], (u16 __user *)msk_isa16_mode(epc)) ||
-			    (__get_user(instr[1], (u16 __user *)msk_isa16_mode(epc + 2)))))
-				goto out_sigsegv;
-			opcode = (instr[0] << 16) | instr[1];
-		} else {
+		u16 instr[2];
+
+		if (__get_user(instr[0], (u16 __user *)epc))
+			goto out_sigsegv;
+
+		if (!cpu_has_mmips) {
 			/* MIPS16e mode */
-			if (__get_user(instr[0],
-				       (u16 __user *)msk_isa16_mode(epc)))
+			bcode = (instr[0] >> 5) & 0x3f;
+		} else if (mm_insn_16bit(instr[0])) {
+			/* 16-bit microMIPS BREAK */
+			bcode = instr[0] & 0xf;
+		} else {
+			/* 32-bit microMIPS BREAK */
+			if (__get_user(instr[1], (u16 __user *)(epc + 2)))
 				goto out_sigsegv;
-			bcode = (instr[0] >> 6) & 0x3f;
-			do_trap_or_bp(regs, bcode, "Break");
-			goto out;
+			opcode = (instr[0] << 16) | instr[1];
+			bcode = (opcode >> 6) & ((1 << 20) - 1);
 		}
 	} else {
-		if (__get_user(opcode,
-			       (unsigned int __user *) exception_epc(regs)))
+		if (__get_user(opcode, (unsigned int __user *)epc))
 			goto out_sigsegv;
+		bcode = (opcode >> 6) & ((1 << 20) - 1);
 	}
 
 	/*
@@ -941,9 +967,8 @@ asmlinkage void do_bp(struct pt_regs *regs)
 	 * Gas is bug-compatible, but not always, grrr...
 	 * We handle both cases with a simple heuristics.  --macro
 	 */
-	bcode = ((opcode >> 6) & ((1 << 20) - 1));
 	if (bcode >= (1 << 10))
-		bcode >>= 10;
+		bcode = ((bcode & ((1 << 10) - 1)) << 10) | (bcode >> 10);
 
 	/*
 	 * notify the kprobe handlers, if instruction is likely to
@@ -1033,22 +1058,24 @@ asmlinkage void do_ri(struct pt_regs *regs)
 	 * as quickly as possible.
 	 */
 	if (mipsr2_emulation && cpu_has_mips_r6 &&
-	    likely(user_mode(regs))) {
-		if (likely(get_user(opcode, epc) >= 0)) {
-			status = mipsr2_decoder(regs, opcode);
-			switch (status) {
-			case 0:
-			case SIGEMT:
-				task_thread_info(current)->r2_emul_return = 1;
-				return;
-			case SIGILL:
-				goto no_r2_instr;
-			default:
-				process_fpemu_return(status,
-						     &current->thread.cp0_baduaddr);
-				task_thread_info(current)->r2_emul_return = 1;
-				return;
-			}
+	    likely(user_mode(regs)) &&
+	    likely(get_user(opcode, epc) >= 0)) {
+		unsigned long fcr31 = 0;
+
+		status = mipsr2_decoder(regs, opcode, &fcr31);
+		switch (status) {
+		case 0:
+		case SIGEMT:
+			task_thread_info(current)->r2_emul_return = 1;
+			return;
+		case SIGILL:
+			goto no_r2_instr;
+		default:
+			process_fpemu_return(status,
+					     &current->thread.cp0_baduaddr,
+					     fcr31);
+			task_thread_info(current)->r2_emul_return = 1;
+			return;
 		}
 	}
 
@@ -1293,10 +1320,13 @@ asmlinkage void do_cpu(struct pt_regs *regs)
 	enum ctx_state prev_state;
 	unsigned int __user *epc;
 	unsigned long old_epc, old31;
+	void __user *fault_addr;
 	unsigned int opcode;
+	unsigned long fcr31;
 	unsigned int cpid;
 	int status, err;
 	unsigned long __maybe_unused flags;
+	int sig;
 
 	prev_state = exception_enter();
 	cpid = (regs->cp0_cause >> CAUSEB_CE) & 3;
@@ -1313,7 +1343,7 @@ asmlinkage void do_cpu(struct pt_regs *regs)
 		status = -1;
 
 		if (unlikely(compute_return_epc(regs) < 0))
-			goto out;
+			break;
 
 		if (get_isa16_mode(regs->cp0_epc)) {
 			unsigned short mmop[2] = { 0 };
@@ -1346,49 +1376,54 @@ asmlinkage void do_cpu(struct pt_regs *regs)
 			force_sig(status, current);
 		}
 
-		goto out;
+		break;
 
 	case 3:
 		/*
-		 * Old (MIPS I and MIPS II) processors will set this code
-		 * for COP1X opcode instructions that replaced the original
-		 * COP3 space.	We don't limit COP1 space instructions in
-		 * the emulator according to the CPU ISA, so we want to
-		 * treat COP1X instructions consistently regardless of which
-		 * code the CPU chose.	Therefore we redirect this trap to
-		 * the FP emulator too.
-		 *
-		 * Then some newer FPU-less processors use this code
-		 * erroneously too, so they are covered by this choice
-		 * as well.
+		 * The COP3 opcode space and consequently the CP0.Status.CU3
+		 * bit and the CP0.Cause.CE=3 encoding have been removed as
+		 * of the MIPS III ISA.  From the MIPS IV and MIPS32r2 ISAs
+		 * up the space has been reused for COP1X instructions, that
+		 * are enabled by the CP0.Status.CU1 bit and consequently
+		 * use the CP0.Cause.CE=1 encoding for Coprocessor Unusable
+		 * exceptions.  Some FPU-less processors that implement one
+		 * of these ISAs however use this code erroneously for COP1X
+		 * instructions.  Therefore we redirect this trap to the FP
+		 * emulator too.
 		 */
-		if (raw_cpu_has_fpu)
+		if (raw_cpu_has_fpu || !cpu_has_mips_4_5_64_r2_r6) {
+			force_sig(SIGILL, current);
 			break;
+		}
 		/* Fall through.  */
 
 	case 1:
 		err = enable_restore_fp_context(0);
 
-		if (!raw_cpu_has_fpu || err) {
-			int sig;
-			void __user *fault_addr = NULL;
-			sig = fpu_emulator_cop1Handler(regs,
-						       &current->thread.fpu,
-						       0, &fault_addr);
-			if (!process_fpemu_return(sig, fault_addr) && !err)
-				mt_ase_fp_affinity();
-		}
+		if (raw_cpu_has_fpu && !err)
+			break;
 
-		goto out;
+		sig = fpu_emulator_cop1Handler(regs, &current->thread.fpu, 0,
+					       &fault_addr);
+		fcr31 = current->thread.fpu.fcr31;
+
+		/*
+		 * We can't allow the emulated instruction to leave
+		 * any of the cause bits set in $fcr31.
+		 */
+		current->thread.fpu.fcr31 &= ~FPU_CSR_ALL_X;
+
+		/* Send a signal if required.  */
+		if (!process_fpemu_return(sig, fault_addr, fcr31) && !err)
+			mt_ase_fp_affinity();
+
+		break;
 
 	case 2:
 		raw_notifier_call_chain(&cu2_chain, CU2_EXCEPTION, regs);
-		goto out;
+		break;
 	}
 
-	force_sig(SIGILL, current);
-
-out:
 	exception_exit(prev_state);
 }
 
@@ -1969,6 +2004,12 @@ int cp0_compare_irq_shift;
 int cp0_perfcount_irq;
 EXPORT_SYMBOL_GPL(cp0_perfcount_irq);
 
+/*
+ * Fast debug channel IRQ or -1 if not present
+ */
+int cp0_fdc_irq;
+EXPORT_SYMBOL_GPL(cp0_fdc_irq);
+
 static int noulri;
 
 static int __init ulri_disable(char *s)
@@ -2050,17 +2091,21 @@ void per_cpu_trap_init(bool is_boot_cpu)
 	 *
 	 *  o read IntCtl.IPTI to determine the timer interrupt
 	 *  o read IntCtl.IPPCI to determine the performance counter interrupt
+	 *  o read IntCtl.IPFDC to determine the fast debug channel interrupt
 	 */
 	if (cpu_has_mips_r2_r6) {
 		cp0_compare_irq_shift = CAUSEB_TI - CAUSEB_IP;
 		cp0_compare_irq = (read_c0_intctl() >> INTCTLB_IPTI) & 7;
 		cp0_perfcount_irq = (read_c0_intctl() >> INTCTLB_IPPCI) & 7;
-		if (cp0_perfcount_irq == cp0_compare_irq)
-			cp0_perfcount_irq = -1;
+		cp0_fdc_irq = (read_c0_intctl() >> INTCTLB_IPFDC) & 7;
+		if (!cp0_fdc_irq)
+			cp0_fdc_irq = -1;
+
 	} else {
 		cp0_compare_irq = CP0_LEGACY_COMPARE_IRQ;
 		cp0_compare_irq_shift = CP0_LEGACY_PERFCNT_IRQ;
 		cp0_perfcount_irq = -1;
+		cp0_fdc_irq = -1;
 	}
 
 	if (!cpu_data[cpu].asid_cache)