sh: Fix occasional FPU register corruption under preempt.

Presently with preempt enabled there's the possibility to be preempted
after the TIF_USEDFPU test and the register save, leading to bogus
state post-__switch_to(). Use an explicit preempt_disable()/enable()
pair around unlazy_fpu()/clear_fpu() to avoid this. Follows the x86
change.

Reported-by: Takuo Koguchi <takuo.koguchi.sw@hitachi.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

6 files changed, 6 insertions, 0 deletions

diff --git a/arch/sh/kernel/cpu/sh2a/fpu.c b/arch/sh/kernel/cpu/sh2a/fpu.c
index ff99562456fb..5627c0b3ffa8 100644
--- a/arch/sh/kernel/cpu/sh2a/fpu.c
+++ b/arch/sh/kernel/cpu/sh2a/fpu.c
@@ -13,6 +13,7 @@
 #include <linux/signal.h>
 #include <asm/processor.h>
 #include <asm/io.h>
+#include <asm/fpu.h>
 
 /* The PR (precision) bit in the FP Status Register must be clear when
  * an frchg instruction is executed, otherwise the instruction is undefined.
diff --git a/arch/sh/kernel/cpu/sh4/fpu.c b/arch/sh/kernel/cpu/sh4/fpu.c
index 817f9939cda6..8020796139f1 100644
--- a/arch/sh/kernel/cpu/sh4/fpu.c
+++ b/arch/sh/kernel/cpu/sh4/fpu.c
@@ -16,6 +16,7 @@
 #include <asm/cpu/fpu.h>
 #include <asm/processor.h>
 #include <asm/system.h>
+#include <asm/fpu.h>
 
 /* The PR (precision) bit in the FP Status Register must be clear when
  * an frchg instruction is executed, otherwise the instruction is undefined.
diff --git a/arch/sh/kernel/cpu/sh5/fpu.c b/arch/sh/kernel/cpu/sh5/fpu.c
index 30b76a94abf2..dd4f51ffb50e 100644
--- a/arch/sh/kernel/cpu/sh5/fpu.c
+++ b/arch/sh/kernel/cpu/sh5/fpu.c
@@ -17,6 +17,7 @@
 #include <asm/processor.h>
 #include <asm/user.h>
 #include <asm/io.h>
+#include <asm/fpu.h>
 
 /*
  * Initially load the FPU with signalling NANS.  This bit pattern
diff --git a/arch/sh/kernel/dump_task.c b/arch/sh/kernel/dump_task.c
index 4a8a4083ff0b..1db7ce0f25d4 100644
--- a/arch/sh/kernel/dump_task.c
+++ b/arch/sh/kernel/dump_task.c
@@ -1,5 +1,6 @@
 #include <linux/elfcore.h>
 #include <linux/sched.h>
+#include <asm/fpu.h>
 
 /*
  * Capture the user space registers if the task is not running (in user space)
diff --git a/arch/sh/kernel/process_32.c b/arch/sh/kernel/process_32.c
index 9ab1926b9d10..b98e37a1f54c 100644
--- a/arch/sh/kernel/process_32.c
+++ b/arch/sh/kernel/process_32.c
@@ -25,6 +25,7 @@
 #include <asm/pgalloc.h>
 #include <asm/system.h>
 #include <asm/ubc.h>
+#include <asm/fpu.h>
 
 static int hlt_counter;
 int ubc_usercnt = 0;
diff --git a/arch/sh/kernel/signal_32.c b/arch/sh/kernel/signal_32.c
index f6b5fbfe75c4..f311551d9a05 100644
--- a/arch/sh/kernel/signal_32.c
+++ b/arch/sh/kernel/signal_32.c
@@ -29,6 +29,7 @@
 #include <asm/uaccess.h>
 #include <asm/pgtable.h>
 #include <asm/cacheflush.h>
+#include <asm/fpu.h>
 
 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))