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>
diff --git a/arch/sh/kernel/cpu/sh2a/fpu.c b/arch/sh/kernel/cpu/sh2a/fpu.c
index ff99562..5627c0b 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 817f993..8020796 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 30b76a9..dd4f51f 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 4a8a408..1db7ce0 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 9ab1926..b98e37a 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 f6b5fbf..f311551 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)))
diff --git a/include/asm-sh/fpu.h b/include/asm-sh/fpu.h
index f842988..f89abf5 100644
--- a/include/asm-sh/fpu.h
+++ b/include/asm-sh/fpu.h
@@ -1,9 +1,8 @@
#ifndef __ASM_SH_FPU_H
#define __ASM_SH_FPU_H
-#define SR_FD 0x00008000
-
#ifndef __ASSEMBLY__
+#include <linux/preempt.h>
#include <asm/ptrace.h>
#ifdef CONFIG_SH_FPU
@@ -28,18 +27,23 @@
extern int do_fpu_inst(unsigned short, struct pt_regs *);
-#define unlazy_fpu(tsk, regs) do { \
- if (test_tsk_thread_flag(tsk, TIF_USEDFPU)) { \
- save_fpu(tsk, regs); \
- } \
-} while (0)
+static inline void unlazy_fpu(struct task_struct *tsk, struct pt_regs *regs)
+{
+ preempt_disable();
+ if (test_tsk_thread_flag(tsk, TIF_USEDFPU))
+ save_fpu(tsk, regs);
+ preempt_enable();
+}
-#define clear_fpu(tsk, regs) do { \
- if (test_tsk_thread_flag(tsk, TIF_USEDFPU)) { \
- clear_tsk_thread_flag(tsk, TIF_USEDFPU); \
- release_fpu(regs); \
- } \
-} while (0)
+static inline void clear_fpu(struct task_struct *tsk, struct pt_regs *regs)
+{
+ preempt_disable();
+ if (test_tsk_thread_flag(tsk, TIF_USEDFPU)) {
+ clear_tsk_thread_flag(tsk, TIF_USEDFPU);
+ release_fpu(regs);
+ }
+ preempt_enable();
+}
#endif /* __ASSEMBLY__ */
diff --git a/include/asm-sh/processor.h b/include/asm-sh/processor.h
index 19fe47c..ec707b9 100644
--- a/include/asm-sh/processor.h
+++ b/include/asm-sh/processor.h
@@ -2,7 +2,6 @@
#define __ASM_SH_PROCESSOR_H
#include <asm/cpu-features.h>
-#include <asm/fpu.h>
#ifndef __ASSEMBLY__
/*
diff --git a/include/asm-sh/processor_32.h b/include/asm-sh/processor_32.h
index df2d5b0..c09305d 100644
--- a/include/asm-sh/processor_32.h
+++ b/include/asm-sh/processor_32.h
@@ -70,6 +70,7 @@
*/
#define SR_DSP 0x00001000
#define SR_IMASK 0x000000f0
+#define SR_FD 0x00008000
/*
* FPU structure and data
diff --git a/include/asm-sh/processor_64.h b/include/asm-sh/processor_64.h
index eda4bef..88a2edf 100644
--- a/include/asm-sh/processor_64.h
+++ b/include/asm-sh/processor_64.h
@@ -112,6 +112,7 @@
#endif
#define SR_IMASK 0x000000f0
+#define SR_FD 0x00008000
#define SR_SSTEP 0x08000000
#ifndef __ASSEMBLY__