unimore/kernel-hacking-2024-linux-steffo
unimore/kernel-hacking-2024-linux-steffo
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m68k: use addr_limit checking for m68k CPUs that do no support address spaces

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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>
This commit is contained in:
Greg Ungerer 2011-10-17 17:31:26 +10:00
parent e08d703cc2
commit feb1ee7595
2 changed files with 19 additions and 14 deletions
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30
arch/m68k/include/asm/segment.h
View file

@ -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)

3
arch/m68k/include/asm/thread_info.h
View file

@ -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, \