s390/uaccess: add HAVE_GET_KERNEL_NOFAULT support

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

diff --git a/arch/s390/include/asm/uaccess.h b/arch/s390/include/asm/uaccess.h
index f09444d..23c8580 100644 (file)
--- a/arch/s390/include/asm/uaccess.h
+++ b/arch/s390/include/asm/uaccess.h
@@ -278,4 +278,115 @@ static inline unsigned long __must_check clear_user(void __user *to, unsigned lo
 int copy_to_user_real(void __user *dest, void *src, unsigned long count);
 void *s390_kernel_write(void *dst, const void *src, size_t size);
 
+#define HAVE_GET_KERNEL_NOFAULT
+
+int __noreturn __put_kernel_bad(void);
+
+#define __put_kernel_asm(val, to, insn)                                        \
+({                                                                     \
+       int __rc;                                                       \
+                                                                       \
+       asm volatile(                                                   \
+               "0:   " insn "  %2,%1\n"                                \
+               "1:     xr      %0,%0\n"                                \
+               "2:\n"                                                  \
+               ".pushsection .fixup, \"ax\"\n"                         \
+               "3:     lhi     %0,%3\n"                                \
+               "       jg      2b\n"                                   \
+               ".popsection\n"                                         \
+               EX_TABLE(0b,3b) EX_TABLE(1b,3b)                         \
+               : "=d" (__rc), "+Q" (*(to))                             \
+               : "d" (val), "K" (-EFAULT)                              \
+               : "cc");                                                \
+       __rc;                                                           \
+})
+
+#define __put_kernel_nofault(dst, src, type, err_label)                        \
+do {                                                                   \
+       u64 __x = (u64)(*((type *)(src)));                              \
+       int __pk_err;                                                   \
+                                                                       \
+       switch (sizeof(type)) {                                         \
+       case 1:                                                         \
+               __pk_err = __put_kernel_asm(__x, (type *)(dst), "stc"); \
+               break;                                                  \
+       case 2:                                                         \
+               __pk_err = __put_kernel_asm(__x, (type *)(dst), "sth"); \
+               break;                                                  \
+       case 4:                                                         \
+               __pk_err = __put_kernel_asm(__x, (type *)(dst), "st");  \
+               break;                                                  \
+       case 8:                                                         \
+               __pk_err = __put_kernel_asm(__x, (type *)(dst), "stg"); \
+               break;                                                  \
+       default:                                                        \
+               __pk_err = __put_kernel_bad();                          \
+               break;                                                  \
+       }                                                               \
+       if (unlikely(__pk_err))                                         \
+               goto err_label;                                         \
+} while (0)
+
+int __noreturn __get_kernel_bad(void);
+
+#define __get_kernel_asm(val, from, insn)                              \
+({                                                                     \
+       int __rc;                                                       \
+                                                                       \
+       asm volatile(                                                   \
+               "0:   " insn "  %1,%2\n"                                \
+               "1:     xr      %0,%0\n"                                \
+               "2:\n"                                                  \
+               ".pushsection .fixup, \"ax\"\n"                         \
+               "3:     lhi     %0,%3\n"                                \
+               "       jg      2b\n"                                   \
+               ".popsection\n"                                         \
+               EX_TABLE(0b,3b) EX_TABLE(1b,3b)                         \
+               : "=d" (__rc), "+d" (val)                               \
+               : "Q" (*(from)), "K" (-EFAULT)                          \
+               : "cc");                                                \
+       __rc;                                                           \
+})
+
+#define __get_kernel_nofault(dst, src, type, err_label)                        \
+do {                                                                   \
+       int __gk_err;                                                   \
+                                                                       \
+       switch (sizeof(type)) {                                         \
+       case 1: {                                                       \
+               u8 __x = 0;                                             \
+                                                                       \
+               __gk_err = __get_kernel_asm(__x, (type *)(src), "ic");  \
+               *((type *)(dst)) = (type)__x;                           \
+               break;                                                  \
+       };                                                              \
+       case 2: {                                                       \
+               u16 __x = 0;                                            \
+                                                                       \
+               __gk_err = __get_kernel_asm(__x, (type *)(src), "lh");  \
+               *((type *)(dst)) = (type)__x;                           \
+               break;                                                  \
+       };                                                              \
+       case 4: {                                                       \
+               u32 __x = 0;                                            \
+                                                                       \
+               __gk_err = __get_kernel_asm(__x, (type *)(src), "l");   \
+               *((type *)(dst)) = (type)__x;                           \
+               break;                                                  \
+       };                                                              \
+       case 8: {                                                       \
+               u64 __x = 0;                                            \
+                                                                       \
+               __gk_err = __get_kernel_asm(__x, (type *)(src), "lg");  \
+               *((type *)(dst)) = (type)__x;                           \
+               break;                                                  \
+       };                                                              \
+       default:                                                        \
+               __gk_err = __get_kernel_bad();                          \
+               break;                                                  \
+       }                                                               \
+       if (unlikely(__gk_err))                                         \
+               goto err_label;                                         \
+} while (0)
+
 #endif /* __S390_UACCESS_H */