get_user_pages: don't try to follow PFNMAP pages

[powerpc.git] / include / asm-i386 / system.h

diff --git a/include/asm-i386/system.h b/include/asm-i386/system.h
index 97d52ac..772f85d 100644 (file)
--- a/include/asm-i386/system.h
+++ b/include/asm-i386/system.h
@@ -263,6 +263,10 @@ static inline unsigned long __xchg(unsigned long x, volatile void * ptr, int siz
 
 #ifdef CONFIG_X86_CMPXCHG
 #define __HAVE_ARCH_CMPXCHG 1
+#define cmpxchg(ptr,o,n)\
+       ((__typeof__(*(ptr)))__cmpxchg((ptr),(unsigned long)(o),\
+                                       (unsigned long)(n),sizeof(*(ptr))))
+#endif
 
 static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
                                      unsigned long new, int size)
@@ -291,10 +295,42 @@ static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
        return old;
 }
 
-#define cmpxchg(ptr,o,n)\
-       ((__typeof__(*(ptr)))__cmpxchg((ptr),(unsigned long)(o),\
-                                       (unsigned long)(n),sizeof(*(ptr))))
+#ifndef CONFIG_X86_CMPXCHG
+/*
+ * Building a kernel capable running on 80386. It may be necessary to
+ * simulate the cmpxchg on the 80386 CPU. For that purpose we define
+ * a function for each of the sizes we support.
+ */
 
+extern unsigned long cmpxchg_386_u8(volatile void *, u8, u8);
+extern unsigned long cmpxchg_386_u16(volatile void *, u16, u16);
+extern unsigned long cmpxchg_386_u32(volatile void *, u32, u32);
+
+static inline unsigned long cmpxchg_386(volatile void *ptr, unsigned long old,
+                                     unsigned long new, int size)
+{
+       switch (size) {
+       case 1:
+               return cmpxchg_386_u8(ptr, old, new);
+       case 2:
+               return cmpxchg_386_u16(ptr, old, new);
+       case 4:
+               return cmpxchg_386_u32(ptr, old, new);
+       }
+       return old;
+}
+
+#define cmpxchg(ptr,o,n)                                               \
+({                                                                     \
+       __typeof__(*(ptr)) __ret;                                       \
+       if (likely(boot_cpu_data.x86 > 3))                              \
+               __ret = __cmpxchg((ptr), (unsigned long)(o),            \
+                                       (unsigned long)(n), sizeof(*(ptr))); \
+       else                                                            \
+               __ret = cmpxchg_386((ptr), (unsigned long)(o),          \
+                                       (unsigned long)(n), sizeof(*(ptr))); \
+       __ret;                                                          \
+})
 #endif
 
 #ifdef CONFIG_X86_CMPXCHG64