[Xen-devel] [PATCHv6 1/3] arm: make __get_user() work for 8 byte values

[David Vrabel <david.vrabel@xxxxxxxxxx>]

get_user(), __put_user(), and put_user() all worked with 8-byte values
but __get_user() did not.

Signed-off-by: David Vrabel <david.vrabel@xxxxxxxxxx>
---
Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
---
 arch/arm/include/asm/uaccess.h |   32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/arch/arm/include/asm/uaccess.h b/arch/arm/include/asm/uaccess.h
index ce0786e..d8f535b 100644
--- a/arch/arm/include/asm/uaccess.h
+++ b/arch/arm/include/asm/uaccess.h
@@ -306,6 +306,7 @@ do {                                                        
                \
        case 1: __get_user_asm_byte(__gu_val, __gu_addr, err);  break;  \
        case 2: __get_user_asm_half(__gu_val, __gu_addr, err);  break;  \
        case 4: __get_user_asm_word(__gu_val, __gu_addr, err);  break;  \
+       case 8: __get_user_asm_dword(__gu_val, __gu_addr, err); break;  \
        default: (__gu_val) = __get_user_bad();                         \
        }                                                               \
        (x) = (__typeof__(*(ptr)))__gu_val;                             \
@@ -365,6 +366,37 @@ do {                                                       
                \
        : "r" (addr), "i" (-EFAULT)                             \
        : "cc")
 
+#ifndef __ARMEB__
+#define        __reg_get0      "%R1"
+#define        __reg_get1      "%Q1"
+#else
+#define        __reg_get0      "%Q1"
+#define        __reg_get1      "%R1"
+#endif
+
+#define __get_user_asm_dword(x, addr, err)                     \
+       __asm__ __volatile__(                                   \
+ ARM(  "1:     " TUSER(ldr) "  " __reg_get1 ", [%2], #4\n"     ) \
+ ARM(  "2:     " TUSER(ldr) "  " __reg_get0 ", [%2]\n" ) \
+ THUMB(        "1:     " TUSER(ldr) "  " __reg_get1 ", [%2]\n" ) \
+ THUMB(        "2:     " TUSER(ldr) "  " __reg_get0 ", [%2, #4]\n"     ) \
+       "3:\n"                                                  \
+       "       .pushsection .fixup,\"ax\"\n"                   \
+       "       .align  2\n"                                    \
+       "4:     mov     %0, %3\n"                               \
+       "       mov     " __reg_get1 ", #0\n"                   \
+       "       mov     " __reg_get0 ", #0\n"                   \
+       "       b       3b\n"                                   \
+       "       .popsection\n"                                  \
+       "       .pushsection __ex_table,\"a\"\n"                \
+       "       .align  3\n"                                    \
+       "       .long   1b, 4b\n"                               \
+       "       .long   2b, 4b\n"                               \
+       "       .popsection"                                    \
+       : "+r" (err), "=&r" (x)                                 \
+       : "r" (addr), "i" (-EFAULT)                             \
+       : "cc")
+
 #define __put_user(x, ptr)                                             \
 ({                                                                     \
        long __pu_err = 0;                                              \
-- 
1.7.10.4


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