Merge branch 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus

* 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus:
  [MIPS] Kconfig: Move missplaced NR_CPUS default from SMTC to VSMP.
  [MIPS] Lockdep: Fix recursion bug.
  [MIPS] RTLX: Handle copy_*_user return values.
  [MIPS] RTLX: Protect rtlx_{read,write} with mutex.
  [MIPS] RTLX: Harden against compiler reordering and optimization.
  [MIPS] RTLX: Don't use volatile; it's fragile.
  [MIPS] Lasat: Downgrade 64-bit kernel from experimental to broken.
  [MIPS] Compat: Fix build if CONFIG_SYSVIPC is disabled.
  [CHAR] lcd: Fix two warnings.
  [MIPS] FPU ownership management & preemption fixes
  [MIPS] Check FCSR for pending interrupts, alternative version
  [MIPS] IP27, IP35: Fix warnings.

13 files changed, 242 insertions, 164 deletions

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 2b9c65c3b5d..5f29018a653 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -250,7 +250,7 @@ config LASAT
 	select R5000_CPU_SCACHE
 	select SYS_HAS_CPU_R5000
 	select SYS_SUPPORTS_32BIT_KERNEL
-	select SYS_SUPPORTS_64BIT_KERNEL if EXPERIMENTAL
+	select SYS_SUPPORTS_64BIT_KERNEL if BROKEN
 	select SYS_SUPPORTS_LITTLE_ENDIAN
 	select GENERIC_HARDIRQS_NO__DO_IRQ
 
@@ -1559,6 +1559,7 @@ config MIPS_MT_SMP
 	select CPU_MIPSR2_IRQ_VI
 	select CPU_MIPSR2_SRS
 	select MIPS_MT
+	select NR_CPUS_DEFAULT_2
 	select SMP
 	select SYS_SUPPORTS_SMP
 	help
@@ -1573,7 +1574,6 @@ config MIPS_MT_SMTC
 	select CPU_MIPSR2_IRQ_VI
 	select CPU_MIPSR2_SRS
 	select MIPS_MT
-	select NR_CPUS_DEFAULT_2
 	select NR_CPUS_DEFAULT_8
 	select SMP
 	select SYS_SUPPORTS_SMP
diff --git a/arch/mips/kernel/kspd.c b/arch/mips/kernel/kspd.c
index 241ee7a2906..29eadd404fa 100644
--- a/arch/mips/kernel/kspd.c
+++ b/arch/mips/kernel/kspd.c
@@ -191,6 +191,8 @@ void sp_work_handle_request(void)
 	struct mtsp_syscall_generic generic;
 	struct mtsp_syscall_ret ret;
 	struct kspd_notifications *n;
+	unsigned long written;
+	mm_segment_t old_fs;
 	struct timeval tv;
 	struct timezone tz;
 	int cmd;
@@ -201,7 +203,11 @@ void sp_work_handle_request(void)
 
 	ret.retval = -1;
 
-	if (!rtlx_read(RTLX_CHANNEL_SYSIO, &sc, sizeof(struct mtsp_syscall), 0)) {
+	old_fs = get_fs();
+	set_fs(KERNEL_DS);
+
+	if (!rtlx_read(RTLX_CHANNEL_SYSIO, &sc, sizeof(struct mtsp_syscall))) {
+		set_fs(old_fs);
 		printk(KERN_ERR "Expected request but nothing to read\n");
 		return;
 	}
@@ -209,7 +215,8 @@ void sp_work_handle_request(void)
 	size = sc.size;
 
 	if (size) {
-		if (!rtlx_read(RTLX_CHANNEL_SYSIO, &generic, size, 0)) {
+		if (!rtlx_read(RTLX_CHANNEL_SYSIO, &generic, size)) {
+			set_fs(old_fs);
 			printk(KERN_ERR "Expected request but nothing to read\n");
 			return;
 		}
@@ -282,8 +289,11 @@ void sp_work_handle_request(void)
 	if (vpe_getuid(SP_VPE))
 		sp_setfsuidgid( 0, 0);
 
-	if ((rtlx_write(RTLX_CHANNEL_SYSIO, &ret, sizeof(struct mtsp_syscall_ret), 0))
-	    < sizeof(struct mtsp_syscall_ret))
+	old_fs = get_fs();
+	set_fs(KERNEL_DS);
+	written = rtlx_write(RTLX_CHANNEL_SYSIO, &ret, sizeof(ret));
+	set_fs(old_fs);
+	if (written < sizeof(ret))
 		printk("KSPD: sp_work_handle_request failed to send to SP\n");
 }
 
diff --git a/arch/mips/kernel/linux32.c b/arch/mips/kernel/linux32.c
index 1df544c1f96..37849edd064 100644
--- a/arch/mips/kernel/linux32.c
+++ b/arch/mips/kernel/linux32.c
@@ -311,6 +311,8 @@ asmlinkage int sys32_sched_rr_get_interval(compat_pid_t pid,
 	return ret;
 }
 
+#ifdef CONFIG_SYSVIPC
+
 asmlinkage long
 sys32_ipc (u32 call, int first, int second, int third, u32 ptr, u32 fifth)
 {
@@ -368,6 +370,16 @@ sys32_ipc (u32 call, int first, int second, int third, u32 ptr, u32 fifth)
 	return err;
 }
 
+#else
+
+asmlinkage long
+sys32_ipc (u32 call, int first, int second, int third, u32 ptr, u32 fifth)
+{
+	return -ENOSYS;
+}
+
+#endif /* CONFIG_SYSVIPC */
+
 #ifdef CONFIG_MIPS32_N32
 asmlinkage long sysn32_semctl(int semid, int semnum, int cmd, u32 arg)
 {
diff --git a/arch/mips/kernel/r2300_switch.S b/arch/mips/kernel/r2300_switch.S
index 656bde2e11b..28c2e2e6af7 100644
--- a/arch/mips/kernel/r2300_switch.S
+++ b/arch/mips/kernel/r2300_switch.S
@@ -49,8 +49,7 @@ LEAF(resume)
 #ifndef CONFIG_CPU_HAS_LLSC
 	sw      zero, ll_bit
 #endif
-	mfc0	t1, CP0_STATUS
-	sw	t1, THREAD_STATUS(a0)
+	mfc0	t2, CP0_STATUS
 	cpu_save_nonscratch a0
 	sw	ra, THREAD_REG31(a0)
 
@@ -60,8 +59,8 @@ LEAF(resume)
 	lw	t3, TASK_THREAD_INFO(a0)
 	lw	t0, TI_FLAGS(t3)
 	li	t1, _TIF_USEDFPU
-	and	t2, t0, t1
-	beqz	t2, 1f
+	and	t1, t0
+	beqz	t1, 1f
 	nor	t1, zero, t1
 
 	and	t0, t0, t1
@@ -74,10 +73,13 @@ LEAF(resume)
 	li	t1, ~ST0_CU1
 	and	t0, t0, t1
 	sw	t0, ST_OFF(t3)
+	/* clear thread_struct CU1 bit */
+	and	t2, t1
 
 	fpu_save_single a0, t0			# clobbers t0
 
 1:
+	sw	t2, THREAD_STATUS(a0)
 	/*
 	 * The order of restoring the registers takes care of the race
 	 * updating $28, $29 and kernelsp without disabling ints.
diff --git a/arch/mips/kernel/r4k_fpu.S b/arch/mips/kernel/r4k_fpu.S
index 59c1577ecbb..dbd42adc52e 100644
--- a/arch/mips/kernel/r4k_fpu.S
+++ b/arch/mips/kernel/r4k_fpu.S
@@ -114,14 +114,6 @@ LEAF(_save_fp_context32)
  */
 LEAF(_restore_fp_context)
 	EX	lw t0, SC_FPC_CSR(a0)
-
-	/* Fail if the CSR has exceptions pending */
-	srl	t1, t0, 5
-	and	t1, t0
-	andi	t1, 0x1f << 7
-	bnez	t1, fault
-	 nop
-
 #ifdef CONFIG_64BIT
 	EX	ldc1 $f1, SC_FPREGS+8(a0)
 	EX	ldc1 $f3, SC_FPREGS+24(a0)
@@ -165,14 +157,6 @@ LEAF(_restore_fp_context)
 LEAF(_restore_fp_context32)
 	/* Restore an o32 sigcontext.  */
 	EX	lw t0, SC32_FPC_CSR(a0)
-
-	/* Fail if the CSR has exceptions pending */
-	srl	t1, t0, 5
-	and	t1, t0
-	andi	t1, 0x1f << 7
-	bnez	t1, fault
-	 nop
-
 	EX	ldc1 $f0, SC32_FPREGS+0(a0)
 	EX	ldc1 $f2, SC32_FPREGS+16(a0)
 	EX	ldc1 $f4, SC32_FPREGS+32(a0)
diff --git a/arch/mips/kernel/r4k_switch.S b/arch/mips/kernel/r4k_switch.S
index cc566cf1224..c7698fd9955 100644
--- a/arch/mips/kernel/r4k_switch.S
+++ b/arch/mips/kernel/r4k_switch.S
@@ -48,8 +48,7 @@
 #ifndef CONFIG_CPU_HAS_LLSC
 	sw	zero, ll_bit
 #endif
-	mfc0	t1, CP0_STATUS
-	LONG_S	t1, THREAD_STATUS(a0)
+	mfc0	t2, CP0_STATUS
 	cpu_save_nonscratch a0
 	LONG_S	ra, THREAD_REG31(a0)
 
@@ -59,8 +58,8 @@
 	PTR_L	t3, TASK_THREAD_INFO(a0)
 	LONG_L	t0, TI_FLAGS(t3)
 	li	t1, _TIF_USEDFPU
-	and	t2, t0, t1
-	beqz	t2, 1f
+	and	t1, t0
+	beqz	t1, 1f
 	nor	t1, zero, t1
 
 	and	t0, t0, t1
@@ -73,10 +72,13 @@
 	li	t1, ~ST0_CU1
 	and	t0, t0, t1
 	LONG_S	t0, ST_OFF(t3)
+	/* clear thread_struct CU1 bit */
+	and	t2, t1
 
 	fpu_save_double a0 t0 t1		# c0_status passed in t0
 						# clobbers t1
 1:
+	LONG_S	t2, THREAD_STATUS(a0)
 
 	/*
 	 * The order of restoring the registers takes care of the race
diff --git a/arch/mips/kernel/rtlx.c b/arch/mips/kernel/rtlx.c
index e14ae09eda2..e6e3047151a 100644
--- a/arch/mips/kernel/rtlx.c
+++ b/arch/mips/kernel/rtlx.c
@@ -54,6 +54,7 @@ static struct chan_waitqueues {
 	wait_queue_head_t rt_queue;
 	wait_queue_head_t lx_queue;
 	atomic_t in_open;
+	struct mutex mutex;
 } channel_wqs[RTLX_CHANNELS];
 
 static struct irqaction irq;
@@ -146,7 +147,7 @@ static void stopping(int vpe)
 
 int rtlx_open(int index, int can_sleep)
 {
-	volatile struct rtlx_info **p;
+	struct rtlx_info **p;
 	struct rtlx_channel *chan;
 	enum rtlx_state state;
 	int ret = 0;
@@ -179,13 +180,24 @@ int rtlx_open(int index, int can_sleep)
 			}
 		}
 
+		smp_rmb();
 		if (*p == NULL) {
 			if (can_sleep) {
-				__wait_event_interruptible(channel_wqs[index].lx_queue,
-				                           *p != NULL,
-				                           ret);
-				if (ret)
+				DEFINE_WAIT(wait);
+
+				for (;;) {
+					prepare_to_wait(&channel_wqs[index].lx_queue, &wait, TASK_INTERRUPTIBLE);
+					smp_rmb();
+					if (*p != NULL)
+						break;
+					if (!signal_pending(current)) {
+						schedule();
+						continue;
+					}
+					ret = -ERESTARTSYS;
 					goto out_fail;
+				}
+				finish_wait(&channel_wqs[index].lx_queue, &wait);
 			} else {
 				printk(" *vpe_get_shared is NULL. "
 				       "Has an SP program been loaded?\n");
@@ -277,56 +289,52 @@ unsigned int rtlx_write_poll(int index)
 	return write_spacefree(chan->rt_read, chan->rt_write, chan->buffer_size);
 }
 
-static inline void copy_to(void *dst, void *src, size_t count, int user)
-{
-	if (user)
-		copy_to_user(dst, src, count);
-	else
-		memcpy(dst, src, count);
-}
-
-static inline void copy_from(void *dst, void *src, size_t count, int user)
+ssize_t rtlx_read(int index, void __user *buff, size_t count, int user)
 {
-	if (user)
-		copy_from_user(dst, src, count);
-	else
-		memcpy(dst, src, count);
-}
-
-ssize_t rtlx_read(int index, void *buff, size_t count, int user)
-{
-	size_t fl = 0L;
+	size_t lx_write, fl = 0L;
 	struct rtlx_channel *lx;
+	unsigned long failed;
 
 	if (rtlx == NULL)
 		return -ENOSYS;
 
 	lx = &rtlx->channel[index];
 
+	mutex_lock(&channel_wqs[index].mutex);
+	smp_rmb();
+	lx_write = lx->lx_write;
+
 	/* find out how much in total */
 	count = min(count,
-		     (size_t)(lx->lx_write + lx->buffer_size - lx->lx_read)
+		     (size_t)(lx_write + lx->buffer_size - lx->lx_read)
 		     % lx->buffer_size);
 
 	/* then how much from the read pointer onwards */
-	fl = min( count, (size_t)lx->buffer_size - lx->lx_read);
+	fl = min(count, (size_t)lx->buffer_size - lx->lx_read);
 
-	copy_to(buff, &lx->lx_buffer[lx->lx_read], fl, user);
+	failed = copy_to_user(buff, lx->lx_buffer + lx->lx_read, fl);
+	if (failed)
+		goto out;
 
 	/* and if there is anything left at the beginning of the buffer */
-	if ( count - fl )
-		copy_to (buff + fl, lx->lx_buffer, count - fl, user);
+	if (count - fl)
+		failed = copy_to_user(buff + fl, lx->lx_buffer, count - fl);
 
-	/* update the index */
-	lx->lx_read += count;
-	lx->lx_read %= lx->buffer_size;
+out:
+	count -= failed;
+
+	smp_wmb();
+	lx->lx_read = (lx->lx_read + count) % lx->buffer_size;
+	smp_wmb();
+	mutex_unlock(&channel_wqs[index].mutex);
 
 	return count;
 }
 
-ssize_t rtlx_write(int index, void *buffer, size_t count, int user)
+ssize_t rtlx_write(int index, const void __user *buffer, size_t count, int user)
 {
 	struct rtlx_channel *rt;
+	size_t rt_read;
 	size_t fl;
 
 	if (rtlx == NULL)
@@ -334,24 +342,35 @@ ssize_t rtlx_write(int index, void *buffer, size_t count, int user)
 
 	rt = &rtlx->channel[index];
 
+	mutex_lock(&channel_wqs[index].mutex);
+	smp_rmb();
+	rt_read = rt->rt_read;
+
 	/* total number of bytes to copy */
 	count = min(count,
-		    (size_t)write_spacefree(rt->rt_read, rt->rt_write,
-					    rt->buffer_size));
+		    (size_t)write_spacefree(rt_read, rt->rt_write, rt->buffer_size));
 
 	/* first bit from write pointer to the end of the buffer, or count */
 	fl = min(count, (size_t) rt->buffer_size - rt->rt_write);
 
-	copy_from (&rt->rt_buffer[rt->rt_write], buffer, fl, user);
+	failed = copy_from_user(rt->rt_buffer + rt->rt_write, buffer, fl);
+	if (failed)
+		goto out;
 
 	/* if there's any left copy to the beginning of the buffer */
-	if( count - fl )
-		copy_from (rt->rt_buffer, buffer + fl, count - fl, user);
+	if (count - fl) {
+		failed = copy_from_user(rt->rt_buffer, buffer + fl, count - fl);
+	}
+
+out:
+	count -= cailed;
 
-	rt->rt_write += count;
-	rt->rt_write %= rt->buffer_size;
+	smp_wmb();
+	rt->rt_write = (rt->rt_write + count) % rt->buffer_size;
+	smp_wmb();
+	mutex_unlock(&channel_wqs[index].mutex);
 
-	return(count);
+	return count;
 }
 
 
@@ -403,7 +422,7 @@ static ssize_t file_read(struct file *file, char __user * buffer, size_t count,
 		return 0;	// -EAGAIN makes cat whinge
 	}
 
-	return rtlx_read(minor, buffer, count, 1);
+	return rtlx_read(minor, buffer, count);
 }
 
 static ssize_t file_write(struct file *file, const char __user * buffer,
@@ -429,7 +448,7 @@ static ssize_t file_write(struct file *file, const char __user * buffer,
 			return ret;
 	}
 
-	return rtlx_write(minor, (void *)buffer, count, 1);
+	return rtlx_write(minor, buffer, count);
 }
 
 static const struct file_operations rtlx_fops = {
@@ -468,6 +487,7 @@ static int rtlx_module_init(void)
 		init_waitqueue_head(&channel_wqs[i].rt_queue);
 		init_waitqueue_head(&channel_wqs[i].lx_queue);
 		atomic_set(&channel_wqs[i].in_open, 0);
+		mutex_init(&channel_wqs[i].mutex);
 
 		dev = device_create(mt_class, NULL, MKDEV(major, i),
 		                    "%s%d", module_name, i);
diff --git a/arch/mips/kernel/signal-common.h b/arch/mips/kernel/signal-common.h
index fdbdbdc65b5..297dfcb9752 100644
--- a/arch/mips/kernel/signal-common.h
+++ b/arch/mips/kernel/signal-common.h
@@ -31,4 +31,7 @@ extern void __user *get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,
  */
 extern int install_sigtramp(unsigned int __user *tramp, unsigned int syscall);
 
+/* Check and clear pending FPU exceptions in saved CSR */
+extern int fpcsr_pending(unsigned int __user *fpcsr);
+
 #endif	/* __SIGNAL_COMMON_H */
diff --git a/arch/mips/kernel/signal.c b/arch/mips/kernel/signal.c
index f091786187a..8c3c5a5789b 100644
--- a/arch/mips/kernel/signal.c
+++ b/arch/mips/kernel/signal.c
@@ -82,6 +82,7 @@ int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
 {
 	int err = 0;
 	int i;
+	unsigned int used_math;
 
 	err |= __put_user(regs->cp0_epc, &sc->sc_pc);
 
@@ -104,26 +105,53 @@ int setup_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
 		err |= __put_user(rddsp(DSP_MASK), &sc->sc_dsp);
 	}
 
-	err |= __put_user(!!used_math(), &sc->sc_used_math);
+	used_math = !!used_math();
+	err |= __put_user(used_math, &sc->sc_used_math);
 
-	if (used_math()) {
+	if (used_math) {
 		/*
 		 * Save FPU state to signal context. Signal handler
 		 * will "inherit" current FPU state.
 		 */
-		preempt_disable();
-
-		if (!is_fpu_owner()) {
-			own_fpu();
-			restore_fp(current);
-		}
+		own_fpu(1);
+		enable_fp_in_kernel();
 		err |= save_fp_context(sc);
-
-		preempt_enable();
+		disable_fp_in_kernel();
 	}
 	return err;
 }
 
+int fpcsr_pending(unsigned int __user *fpcsr)
+{
+	int err, sig = 0;
+	unsigned int csr, enabled;
+
+	err = __get_user(csr, fpcsr);
+	enabled = FPU_CSR_UNI_X | ((csr & FPU_CSR_ALL_E) << 5);
+	/*
+	 * If the signal handler set some FPU exceptions, clear it and
+	 * send SIGFPE.
+	 */
+	if (csr & enabled) {
+		csr &= ~enabled;
+		err |= __put_user(csr, fpcsr);
+		sig = SIGFPE;
+	}
+	return err ?: sig;
+}
+
+static int
+check_and_restore_fp_context(struct sigcontext __user *sc)
+{
+	int err, sig;
+
+	err = sig = fpcsr_pending(&sc->sc_fpc_csr);
+	if (err > 0)
+		err = 0;
+	err |= restore_fp_context(sc);
+	return err ?: sig;
+}
+
 int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
 {
 	unsigned int used_math;
@@ -157,19 +185,18 @@ int restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc)
 	err |= __get_user(used_math, &sc->sc_used_math);
 	conditional_used_math(used_math);
 
-	preempt_disable();
-
-	if (used_math()) {
+	if (used_math) {
 		/* restore fpu context if we have used it before */
-		own_fpu();
-		err |= restore_fp_context(sc);
+		own_fpu(0);
+		enable_fp_in_kernel();
+		if (!err)
+			err = check_and_restore_fp_context(sc);
+		disable_fp_in_kernel();
 	} else {
 		/* signal handler may have used FPU.  Give it up. */
-		lose_fpu();
+		lose_fpu(0);
 	}
 
-	preempt_enable();
-
 	return err;
 }
 
@@ -332,6 +359,7 @@ asmlinkage void sys_sigreturn(nabi_no_regargs struct pt_regs regs)
 {
 	struct sigframe __user *frame;
 	sigset_t blocked;
+	int sig;
 
 	frame = (struct sigframe __user *) regs.regs[29];
 	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
@@ -345,8 +373,11 @@ asmlinkage void sys_sigreturn(nabi_no_regargs struct pt_regs regs)
 	recalc_sigpending();
 	spin_unlock_irq(&current->sighand->siglock);
 
-	if (restore_sigcontext(&regs, &frame->sf_sc))
+	sig = restore_sigcontext(&regs, &frame->sf_sc);
+	if (sig < 0)
 		goto badframe;
+	else if (sig)
+		force_sig(sig, current);
 
 	/*
 	 * Don't let your children do this ...
@@ -368,6 +399,7 @@ asmlinkage void sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
 	struct rt_sigframe __user *frame;
 	sigset_t set;
 	stack_t st;
+	int sig;
 
 	frame = (struct rt_sigframe __user *) regs.regs[29];
 	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
@@ -381,8 +413,11 @@ asmlinkage void sys_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
 	recalc_sigpending();
 	spin_unlock_irq(&current->sighand->siglock);
 
-	if (restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext))
+	sig = restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext);
+	if (sig < 0)
 		goto badframe;
+	else if (sig)
+		force_sig(sig, current);
 
 	if (__copy_from_user(&st, &frame->rs_uc.uc_stack, sizeof(st)))
 		goto badframe;
diff --git a/arch/mips/kernel/signal32.c b/arch/mips/kernel/signal32.c
index 19bbef00195..151fd2f0893 100644
--- a/arch/mips/kernel/signal32.c
+++ b/arch/mips/kernel/signal32.c
@@ -181,6 +181,7 @@ static int setup_sigcontext32(struct pt_regs *regs,
 {
 	int err = 0;
 	int i;
+	u32 used_math;
 
 	err |= __put_user(regs->cp0_epc, &sc->sc_pc);
 
@@ -200,26 +201,34 @@ static int setup_sigcontext32(struct pt_regs *regs,
 		err |= __put_user(mflo3(), &sc->sc_lo3);
 	}
 
-	err |= __put_user(!!used_math(), &sc->sc_used_math);
+	used_math = !!used_math();
+	err |= __put_user(used_math, &sc->sc_used_math);
 
-	if (used_math()) {
+	if (used_math) {
 		/*
 		 * Save FPU state to signal context.  Signal handler
 		 * will "inherit" current FPU state.
 		 */
-		preempt_disable();
-
-		if (!is_fpu_owner()) {
-			own_fpu();
-			restore_fp(current);
-		}
+		own_fpu(1);
+		enable_fp_in_kernel();
 		err |= save_fp_context32(sc);
-
-		preempt_enable();
+		disable_fp_in_kernel();
 	}
 	return err;
 }
 
+static int
+check_and_restore_fp_context32(struct sigcontext32 __user *sc)
+{
+	int err, sig;
+
+	err = sig = fpcsr_pending(&sc->sc_fpc_csr);
+	if (err > 0)
+		err = 0;
+	err |= restore_fp_context32(sc);
+	return err ?: sig;
+}
+
 static int restore_sigcontext32(struct pt_regs *regs,
 				struct sigcontext32 __user *sc)
 {
@@ -250,19 +259,18 @@ static int restore_sigcontext32(struct pt_regs *regs,
 	err |= __get_user(used_math, &sc->sc_used_math);
 	conditional_used_math(used_math);
 
-	preempt_disable();
-
-	if (used_math()) {
+	if (used_math) {
 		/* restore fpu context if we have used it before */
-		own_fpu();
-		err |= restore_fp_context32(sc);
+		own_fpu(0);
+		enable_fp_in_kernel();
+		if (!err)
+			err = check_and_restore_fp_context32(sc);
+		disable_fp_in_kernel();
 	} else {
 		/* signal handler may have used FPU.  Give it up. */
-		lose_fpu();
+		lose_fpu(0);
 	}
 
-	preempt_enable();
-
 	return err;
 }
 
@@ -508,6 +516,7 @@ asmlinkage void sys32_sigreturn(nabi_no_regargs struct pt_regs regs)
 {
 	struct sigframe32 __user *frame;
 	sigset_t blocked;
+	int sig;
 
 	frame = (struct sigframe32 __user *) regs.regs[29];
 	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
@@ -521,8 +530,11 @@ asmlinkage void sys32_sigreturn(nabi_no_regargs struct pt_regs regs)
 	recalc_sigpending();
 	spin_unlock_irq(&current->sighand->siglock);
 
-	if (restore_sigcontext32(&regs, &frame->sf_sc))
+	sig = restore_sigcontext32(&regs, &frame->sf_sc);
+	if (sig < 0)
 		goto badframe;
+	else if (sig)
+		force_sig(sig, current);
 
 	/*
 	 * Don't let your children do this ...
@@ -545,6 +557,7 @@ asmlinkage void sys32_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
 	sigset_t set;
 	stack_t st;
 	s32 sp;
+	int sig;
 
 	frame = (struct rt_sigframe32 __user *) regs.regs[29];
 	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
@@ -558,8 +571,11 @@ asmlinkage void sys32_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
 	recalc_sigpending();
 	spin_unlock_irq(&current->sighand->siglock);
 
-	if (restore_sigcontext32(&regs, &frame->rs_uc.uc_mcontext))
+	sig = restore_sigcontext32(&regs, &frame->rs_uc.uc_mcontext);
+	if (sig < 0)
 		goto badframe;
+	else if (sig)
+		force_sig(sig, current);
 
 	/* The ucontext contains a stack32_t, so we must convert!  */
 	if (__get_user(sp, &frame->rs_uc.uc_stack.ss_sp))
diff --git a/arch/mips/kernel/signal_n32.c b/arch/mips/kernel/signal_n32.c
index ecf1f7ecaad..a9202fa9598 100644
--- a/arch/mips/kernel/signal_n32.c
+++ b/arch/mips/kernel/signal_n32.c
@@ -127,6 +127,7 @@ asmlinkage void sysn32_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
 	sigset_t set;
 	stack_t st;
 	s32 sp;
+	int sig;
 
 	frame = (struct rt_sigframe_n32 __user *) regs.regs[29];
 	if (!access_ok(VERIFY_READ, frame, sizeof(*frame)))
@@ -140,8 +141,11 @@ asmlinkage void sysn32_rt_sigreturn(nabi_no_regargs struct pt_regs regs)
 	recalc_sigpending();
 	spin_unlock_irq(&current->sighand->siglock);
 
-	if (restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext))
+	sig = restore_sigcontext(&regs, &frame->rs_uc.uc_mcontext);
+	if (sig < 0)
 		goto badframe;
+	else if (sig)
+		force_sig(sig, current);
 
 	/* The ucontext contains a stack32_t, so we must convert!  */
 	if (__get_user(sp, &frame->rs_uc.uc_stack.ss_sp))
diff --git a/arch/mips/kernel/traps.c b/arch/mips/kernel/traps.c
index 18f56a9dbcf..7d76a85422b 100644
--- a/arch/mips/kernel/traps.c
+++ b/arch/mips/kernel/traps.c
@@ -610,16 +610,6 @@ asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
 	if (fcr31 & FPU_CSR_UNI_X) {
 		int sig;
 
-		preempt_disable();
-
-#ifdef CONFIG_PREEMPT
-		if (!is_fpu_owner()) {
-			/* We might lose fpu before disabling preempt... */
-			own_fpu();
-			BUG_ON(!used_math());
-			restore_fp(current);
-		}
-#endif
 		/*
 		 * Unimplemented operation exception.  If we've got the full
 		 * software emulator on-board, let's use it...
@@ -630,18 +620,12 @@ asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
 		 * register operands before invoking the emulator, which seems
 		 * a bit extreme for what should be an infrequent event.
 		 */
-		save_fp(current);
 		/* Ensure 'resume' not overwrite saved fp context again. */
-		lose_fpu();
-
-		preempt_enable();
+		lose_fpu(1);
 
 		/* Run the emulator */
 		sig = fpu_emulator_cop1Handler (regs, &current->thread.fpu, 1);
 
-		preempt_disable();
-
-		own_fpu();	/* Using the FPU again.  */
 		/*
 		 * We can't allow the emulated instruction to leave any of
 		 * the cause bit set in $fcr31.
@@ -649,9 +633,7 @@ asmlinkage void do_fpe(struct pt_regs *regs, unsigned long fcr31)
 		current->thread.fpu.fcr31 &= ~FPU_CSR_ALL_X;
 
 		/* Restore the hardware register state */
-		restore_fp(current);
-
-		preempt_enable();
+		own_fpu(1);	/* Using the FPU again.  */
 
 		/* If something went wrong, signal */
 		if (sig)
@@ -775,12 +757,11 @@ asmlinkage void do_cpu(struct pt_regs *regs)
 {
 	unsigned int cpid;
 
-	die_if_kernel("do_cpu invoked from kernel context!", regs);
-
 	cpid = (regs->cp0_cause >> CAUSEB_CE) & 3;
 
 	switch (cpid) {
 	case 0:
+		die_if_kernel("do_cpu invoked from kernel context!", regs);
 		if (!cpu_has_llsc)
 			if (!simulate_llsc(regs))
 				return;
@@ -791,21 +772,30 @@ asmlinkage void do_cpu(struct pt_regs *regs)
 		break;
 
 	case 1:
-		preempt_disable();
-
-		own_fpu();
-		if (used_math()) {	/* Using the FPU again.  */
-			restore_fp(current);
-		} else {			/* First time FPU user.  */
+		if (!test_thread_flag(TIF_ALLOW_FP_IN_KERNEL))
+			die_if_kernel("do_cpu invoked from kernel context!",
+				      regs);
+		if (used_math())	/* Using the FPU again.  */
+			own_fpu(1);
+		else {			/* First time FPU user.  */
 			init_fpu();
 			set_used_math();
 		}
 
-		if (cpu_has_fpu) {
-			preempt_enable();
+		if (raw_cpu_has_fpu) {
+			if (test_thread_flag(TIF_ALLOW_FP_IN_KERNEL)) {
+				local_irq_disable();
+				if (cpu_has_fpu)
+					regs->cp0_status |= ST0_CU1;
+				/*
+				 * We must return without enabling
+				 * interrupts to ensure keep FPU
+				 * ownership until resume.
+				 */
+				return;
+			}
 		} else {
 			int sig;
-			preempt_enable();
 			sig = fpu_emulator_cop1Handler(regs,
 						&current->thread.fpu, 0);
 			if (sig)
@@ -1259,26 +1249,26 @@ static inline void mips_srs_init(void)
 /*
  * This is used by native signal handling
  */
-asmlinkage int (*save_fp_context)(struct sigcontext *sc);
-asmlinkage int (*restore_fp_context)(struct sigcontext *sc);
+asmlinkage int (*save_fp_context)(struct sigcontext __user *sc);
+asmlinkage int (*restore_fp_context)(struct sigcontext __user *sc);
 
-extern asmlinkage int _save_fp_context(struct sigcontext *sc);
-extern asmlinkage int _restore_fp_context(struct sigcontext *sc);
+extern asmlinkage int _save_fp_context(struct sigcontext __user *sc);
+extern asmlinkage int _restore_fp_context(struct sigcontext __user *sc);
 
-extern asmlinkage int fpu_emulator_save_context(struct sigcontext *sc);
-extern asmlinkage int fpu_emulator_restore_context(struct sigcontext *sc);
+extern asmlinkage int fpu_emulator_save_context(struct sigcontext __user *sc);
+extern asmlinkage int fpu_emulator_restore_context(struct sigcontext __user *sc);
 
 #ifdef CONFIG_SMP
-static int smp_save_fp_context(struct sigcontext *sc)
+static int smp_save_fp_context(struct sigcontext __user *sc)
 {
-	return cpu_has_fpu
+	return raw_cpu_has_fpu
 	       ? _save_fp_context(sc)
 	       : fpu_emulator_save_context(sc);
 }
 
-static int smp_restore_fp_context(struct sigcontext *sc)
+static int smp_restore_fp_context(struct sigcontext __user *sc)
 {
-	return cpu_has_fpu
+	return raw_cpu_has_fpu
 	       ? _restore_fp_context(sc)
 	       : fpu_emulator_restore_context(sc);
 }
@@ -1306,14 +1296,14 @@ static inline void signal_init(void)
 /*
  * This is used by 32-bit signal stuff on the 64-bit kernel
  */
-asmlinkage int (*save_fp_context32)(struct sigcontext32 *sc);
-asmlinkage int (*restore_fp_context32)(struct sigcontext32 *sc);
+asmlinkage int (*save_fp_context32)(struct sigcontext32 __user *sc);
+asmlinkage int (*restore_fp_context32)(struct sigcontext32 __user *sc);
 
-extern asmlinkage int _save_fp_context32(struct sigcontext32 *sc);
-extern asmlinkage int _restore_fp_context32(struct sigcontext32 *sc);
+extern asmlinkage int _save_fp_context32(struct sigcontext32 __user *sc);
+extern asmlinkage int _restore_fp_context32(struct sigcontext32 __user *sc);
 
-extern asmlinkage int fpu_emulator_save_context32(struct sigcontext32 *sc);
-extern asmlinkage int fpu_emulator_restore_context32(struct sigcontext32 *sc);
+extern asmlinkage int fpu_emulator_save_context32(struct sigcontext32 __user *sc);
+extern asmlinkage int fpu_emulator_restore_context32(struct sigcontext32 __user *sc);
 
 static inline void signal32_init(void)
 {
diff --git a/arch/mips/math-emu/kernel_linkage.c b/arch/mips/math-emu/kernel_linkage.c
index 5b3390f6491..ed49ef01ac5 100644
--- a/arch/mips/math-emu/kernel_linkage.c
+++ b/arch/mips/math-emu/kernel_linkage.c
@@ -51,7 +51,7 @@ void fpu_emulator_init_fpu(void)
  * with appropriate macros from uaccess.h
  */
 
-int fpu_emulator_save_context(struct sigcontext *sc)
+int fpu_emulator_save_context(struct sigcontext __user *sc)
 {
 	int i;
 	int err = 0;
@@ -65,7 +65,7 @@ int fpu_emulator_save_context(struct sigcontext *sc)
 	return err;
 }
 
-int fpu_emulator_restore_context(struct sigcontext *sc)
+int fpu_emulator_restore_context(struct sigcontext __user *sc)
 {
 	int i;
 	int err = 0;
@@ -84,7 +84,7 @@ int fpu_emulator_restore_context(struct sigcontext *sc)
  * This is the o32 version
  */
 
-int fpu_emulator_save_context32(struct sigcontext32 *sc)
+int fpu_emulator_save_context32(struct sigcontext32 __user *sc)
 {
 	int i;
 	int err = 0;
@@ -98,7 +98,7 @@ int fpu_emulator_save_context32(struct sigcontext32 *sc)
 	return err;
 }
 
-int fpu_emulator_restore_context32(struct sigcontext32 *sc)
+int fpu_emulator_restore_context32(struct sigcontext32 __user *sc)
 {
 	int i;
 	int err = 0;