[PATCH 07/35] m68k: use addr_limit checking for m68k CPUs that do no support address spaces

gerg
2011-12-16T12:36:41Z

The ColdFire CPU family, and the original 68000, do not support separate
address spaces like the other 680x0 CPU types. Modify the set_fs()/get_fs()
functions and macros to use a thread_info addr_limit for address space
checking. This is pretty much what all other architectures that do not
support separate setable address spaces do.

Signed-off-by: Alexander Stein <alexander.stein@systec-electronic.com>
Signed-off-by: Greg Ungerer <gerg@uclinux.org>
Acked-by: Matt Waddel <mwaddel@yahoo.com>
Acked-by: Kurt Mahan <kmahan@xmission.com>
---
arch/m68k/include/asm/segment.h | 30 ++++++++++++++++--------------
arch/m68k/include/asm/thread_info.h | 3 +++
2 files changed, 19 insertions(+), 14 deletions(-)

diff --git a/arch/m68k/include/asm/segment.h b/arch/m68k/include/asm/segment.h
index 1a142e9..0fa80e9 100644
--- a/arch/m68k/include/asm/segment.h
+++ b/arch/m68k/include/asm/segment.h
@@ -22,23 +22,26 @@ typedef struct {
} mm_segment_t;

#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
-#define USER_DS MAKE_MM_SEG(__USER_DS)
-#define KERNEL_DS MAKE_MM_SEG(__KERNEL_DS)

+#ifdef CONFIG_CPU_HAS_ADDRESS_SPACES
/*
* Get/set the SFC/DFC registers for MOVES instructions
*/
+#define USER_DS MAKE_MM_SEG(__USER_DS)
+#define KERNEL_DS MAKE_MM_SEG(__KERNEL_DS)

static inline mm_segment_t get_fs(void)
{
-#ifdef CONFIG_CPU_HAS_ADDRESS_SPACES
mm_segment_t _v;
__asm__ ("movec %/dfc,%0":"=r" (_v.seg):);
-
return _v;
-#else
- return USER_DS;
-#endif
+}
+
+static inline void set_fs(mm_segment_t val)
+{
+ __asm__ __volatile__ ("movec %0,%/sfc\n\t"
+ "movec %0,%/dfc\n\t"
+ : /* no outputs */ : "r" (val.seg) : "memory");
}

static inline mm_segment_t get_ds(void)
@@ -47,14 +50,13 @@ static inline mm_segment_t get_ds(void)
return KERNEL_DS;
}

-static inline void set_fs(mm_segment_t val)
-{
-#ifdef CONFIG_CPU_HAS_ADDRESS_SPACES
- __asm__ __volatile__ ("movec %0,%/sfc\n\t"
- "movec %0,%/dfc\n\t"
- : /* no outputs */ : "r" (val.seg) : "memory");
+#else
+#define USER_DS MAKE_MM_SEG(TASK_SIZE)
+#define KERNEL_DS MAKE_MM_SEG(0xFFFFFFFF)
+#define get_ds() (KERNEL_DS)
+#define get_fs() (current_thread_info()->addr_limit)
+#define set_fs(x) (current_thread_info()->addr_limit = (x))
#endif
-}

#define segment_eq(a,b) ((a).seg == (b).seg)

diff --git a/arch/m68k/include/asm/thread_info.h b/arch/m68k/include/asm/thread_info.h
index 01cef3c..29fa6da 100644
--- a/arch/m68k/include/asm/thread_info.h
+++ b/arch/m68k/include/asm/thread_info.h
@@ -3,6 +3,7 @@

#include <asm/types.h>
#include <asm/page.h>
+#include <asm/segment.h>

/*
* On machines with 4k pages we default to an 8k thread size, though we
@@ -26,6 +27,7 @@ struct thread_info {
struct task_struct *task; /* main task structure */
unsigned long flags;
struct exec_domain *exec_domain; /* execution domain */
+ mm_segment_t addr_limit; /* thread address space */
int preempt_count; /* 0 => preemptable, <0 => BUG */
__u32 cpu; /* should always be 0 on m68k */
unsigned long tp_value; /* thread pointer */
@@ -39,6 +41,7 @@ struct thread_info {
{ \
.task = &tsk, \
.exec_domain = &default_exec_domain, \
+ .addr_limit = KERNEL_DS, \
.preempt_count = INIT_PREEMPT_COUNT, \
.restart_block = { \
.fn = do_no_restart_syscall, \
--
1.7.0.4