summaryrefslogtreecommitdiff
path: root/arch/m68k/include/asm/system_mm.h
diff options
context:
space:
mode:
Diffstat (limited to 'arch/m68k/include/asm/system_mm.h')
-rw-r--r--arch/m68k/include/asm/system_mm.h218
1 files changed, 218 insertions, 0 deletions
diff --git a/arch/m68k/include/asm/system_mm.h b/arch/m68k/include/asm/system_mm.h
new file mode 100644
index 000000000000..dbb6515ffd5b
--- /dev/null
+++ b/arch/m68k/include/asm/system_mm.h
@@ -0,0 +1,218 @@
+#ifndef _M68K_SYSTEM_H
+#define _M68K_SYSTEM_H
+
+#include <linux/linkage.h>
+#include <linux/kernel.h>
+#include <asm/segment.h>
+#include <asm/entry.h>
+
+#ifdef __KERNEL__
+
+/*
+ * switch_to(n) should switch tasks to task ptr, first checking that
+ * ptr isn't the current task, in which case it does nothing. This
+ * also clears the TS-flag if the task we switched to has used the
+ * math co-processor latest.
+ */
+/*
+ * switch_to() saves the extra registers, that are not saved
+ * automatically by SAVE_SWITCH_STACK in resume(), ie. d0-d5 and
+ * a0-a1. Some of these are used by schedule() and its predecessors
+ * and so we might get see unexpected behaviors when a task returns
+ * with unexpected register values.
+ *
+ * syscall stores these registers itself and none of them are used
+ * by syscall after the function in the syscall has been called.
+ *
+ * Beware that resume now expects *next to be in d1 and the offset of
+ * tss to be in a1. This saves a few instructions as we no longer have
+ * to push them onto the stack and read them back right after.
+ *
+ * 02/17/96 - Jes Sorensen (jds@kom.auc.dk)
+ *
+ * Changed 96/09/19 by Andreas Schwab
+ * pass prev in a0, next in a1
+ */
+asmlinkage void resume(void);
+#define switch_to(prev,next,last) do { \
+ register void *_prev __asm__ ("a0") = (prev); \
+ register void *_next __asm__ ("a1") = (next); \
+ register void *_last __asm__ ("d1"); \
+ __asm__ __volatile__("jbsr resume" \
+ : "=a" (_prev), "=a" (_next), "=d" (_last) \
+ : "0" (_prev), "1" (_next) \
+ : "d0", "d2", "d3", "d4", "d5"); \
+ (last) = _last; \
+} while (0)
+
+
+/*
+ * Force strict CPU ordering.
+ * Not really required on m68k...
+ */
+#define nop() do { asm volatile ("nop"); barrier(); } while (0)
+#define mb() barrier()
+#define rmb() barrier()
+#define wmb() barrier()
+#define read_barrier_depends() ((void)0)
+#define set_mb(var, value) ({ (var) = (value); wmb(); })
+
+#define smp_mb() barrier()
+#define smp_rmb() barrier()
+#define smp_wmb() barrier()
+#define smp_read_barrier_depends() ((void)0)
+
+/* interrupt control.. */
+#if 0
+#define local_irq_enable() asm volatile ("andiw %0,%%sr": : "i" (ALLOWINT) : "memory")
+#else
+#include <linux/hardirq.h>
+#define local_irq_enable() ({ \
+ if (MACH_IS_Q40 || !hardirq_count()) \
+ asm volatile ("andiw %0,%%sr": : "i" (ALLOWINT) : "memory"); \
+})
+#endif
+#define local_irq_disable() asm volatile ("oriw #0x0700,%%sr": : : "memory")
+#define local_save_flags(x) asm volatile ("movew %%sr,%0":"=d" (x) : : "memory")
+#define local_irq_restore(x) asm volatile ("movew %0,%%sr": :"d" (x) : "memory")
+
+static inline int irqs_disabled(void)
+{
+ unsigned long flags;
+ local_save_flags(flags);
+ return flags & ~ALLOWINT;
+}
+
+/* For spinlocks etc */
+#define local_irq_save(x) ({ local_save_flags(x); local_irq_disable(); })
+
+#define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr))))
+
+struct __xchg_dummy { unsigned long a[100]; };
+#define __xg(x) ((volatile struct __xchg_dummy *)(x))
+
+#ifndef CONFIG_RMW_INSNS
+static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size)
+{
+ unsigned long flags, tmp;
+
+ local_irq_save(flags);
+
+ switch (size) {
+ case 1:
+ tmp = *(u8 *)ptr;
+ *(u8 *)ptr = x;
+ x = tmp;
+ break;
+ case 2:
+ tmp = *(u16 *)ptr;
+ *(u16 *)ptr = x;
+ x = tmp;
+ break;
+ case 4:
+ tmp = *(u32 *)ptr;
+ *(u32 *)ptr = x;
+ x = tmp;
+ break;
+ default:
+ BUG();
+ }
+
+ local_irq_restore(flags);
+ return x;
+}
+#else
+static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int size)
+{
+ switch (size) {
+ case 1:
+ __asm__ __volatile__
+ ("moveb %2,%0\n\t"
+ "1:\n\t"
+ "casb %0,%1,%2\n\t"
+ "jne 1b"
+ : "=&d" (x) : "d" (x), "m" (*__xg(ptr)) : "memory");
+ break;
+ case 2:
+ __asm__ __volatile__
+ ("movew %2,%0\n\t"
+ "1:\n\t"
+ "casw %0,%1,%2\n\t"
+ "jne 1b"
+ : "=&d" (x) : "d" (x), "m" (*__xg(ptr)) : "memory");
+ break;
+ case 4:
+ __asm__ __volatile__
+ ("movel %2,%0\n\t"
+ "1:\n\t"
+ "casl %0,%1,%2\n\t"
+ "jne 1b"
+ : "=&d" (x) : "d" (x), "m" (*__xg(ptr)) : "memory");
+ break;
+ }
+ return x;
+}
+#endif
+
+#include <asm-generic/cmpxchg-local.h>
+
+#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
+
+/*
+ * Atomic compare and exchange. Compare OLD with MEM, if identical,
+ * store NEW in MEM. Return the initial value in MEM. Success is
+ * indicated by comparing RETURN with OLD.
+ */
+#ifdef CONFIG_RMW_INSNS
+#define __HAVE_ARCH_CMPXCHG 1
+
+static inline unsigned long __cmpxchg(volatile void *p, unsigned long old,
+ unsigned long new, int size)
+{
+ switch (size) {
+ case 1:
+ __asm__ __volatile__ ("casb %0,%2,%1"
+ : "=d" (old), "=m" (*(char *)p)
+ : "d" (new), "0" (old), "m" (*(char *)p));
+ break;
+ case 2:
+ __asm__ __volatile__ ("casw %0,%2,%1"
+ : "=d" (old), "=m" (*(short *)p)
+ : "d" (new), "0" (old), "m" (*(short *)p));
+ break;
+ case 4:
+ __asm__ __volatile__ ("casl %0,%2,%1"
+ : "=d" (old), "=m" (*(int *)p)
+ : "d" (new), "0" (old), "m" (*(int *)p));
+ break;
+ }
+ return old;
+}
+
+#define cmpxchg(ptr, o, n) \
+ ((__typeof__(*(ptr)))__cmpxchg((ptr), (unsigned long)(o), \
+ (unsigned long)(n), sizeof(*(ptr))))
+#define cmpxchg_local(ptr, o, n) \
+ ((__typeof__(*(ptr)))__cmpxchg((ptr), (unsigned long)(o), \
+ (unsigned long)(n), sizeof(*(ptr))))
+#else
+
+/*
+ * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make
+ * them available.
+ */
+#define cmpxchg_local(ptr, o, n) \
+ ((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\
+ (unsigned long)(n), sizeof(*(ptr))))
+
+#ifndef CONFIG_SMP
+#include <asm-generic/cmpxchg.h>
+#endif
+
+#endif
+
+#define arch_align_stack(x) (x)
+
+#endif /* __KERNEL__ */
+
+#endif /* _M68K_SYSTEM_H */