[PATCH 4.10 60/69] parisc: Fix get_user() for 64-bit value on 32-bit kernel

Greg Kroah-Hartman
2017-04-19T15:20:03Z

From: Helge Deller <deller@gmx.de>

commit 3f795cef0ecdf9bc980dd058d49bdab4b19af1d3 upstream.

This fixes a bug in which the upper 32-bits of a 64-bit value which is
read by get_user() was lost on a 32-bit kernel.
While touching this code, split out pre-loading of %sr2 space register
and clean up code indent.

Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/parisc/include/asm/uaccess.h | 86 ++++++++++++++++++++++++--------------
1 file changed, 55 insertions(+), 31 deletions(-)

--- a/arch/parisc/include/asm/uaccess.h
+++ b/arch/parisc/include/asm/uaccess.h
@@ -42,10 +42,10 @@ static inline long access_ok(int type, c
#define get_user __get_user

#if !defined(CONFIG_64BIT)
-#define LDD_USER(ptr) __get_user_asm64(ptr)
+#define LDD_USER(val, ptr) __get_user_asm64(val, ptr)
#define STD_USER(x, ptr) __put_user_asm64(x, ptr)
#else
-#define LDD_USER(ptr) __get_user_asm("ldd", ptr)
+#define LDD_USER(val, ptr) __get_user_asm(val, "ldd", ptr)
#define STD_USER(x, ptr) __put_user_asm("std", x, ptr)
#endif

@@ -100,63 +100,87 @@ struct exception_data {
" mtsp %0,%%sr2\n\t" \
: : "r"(get_fs()) : )

-#define __get_user(x, ptr) \
-({ \
- register long __gu_err __asm__ ("r8") = 0; \
- register long __gu_val; \
- \
- load_sr2(); \
- switch (sizeof(*(ptr))) { \
- case 1: __get_user_asm("ldb", ptr); break; \
- case 2: __get_user_asm("ldh", ptr); break; \
- case 4: __get_user_asm("ldw", ptr); break; \
- case 8: LDD_USER(ptr); break; \
- default: BUILD_BUG(); break; \
- } \
- \
- (x) = (__force __typeof__(*(ptr))) __gu_val; \
- __gu_err; \
+#define __get_user_internal(val, ptr) \
+({ \
+ register long __gu_err __asm__ ("r8") = 0; \
+ \
+ switch (sizeof(*(ptr))) { \
+ case 1: __get_user_asm(val, "ldb", ptr); break; \
+ case 2: __get_user_asm(val, "ldh", ptr); break; \
+ case 4: __get_user_asm(val, "ldw", ptr); break; \
+ case 8: LDD_USER(val, ptr); break; \
+ default: BUILD_BUG(); \
+ } \
+ \
+ __gu_err; \
})

-#define __get_user_asm(ldx, ptr) \
+#define __get_user(val, ptr) \
+({ \
+ load_sr2(); \
+ __get_user_internal(val, ptr); \
+})
+
+#define __get_user_asm(val, ldx, ptr) \
+{ \
+ register long __gu_val; \
+ \
__asm__("1: " ldx " 0(%%sr2,%2),%0\n" \
"9:\n" \
ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 9b) \
: "=r"(__gu_val), "=r"(__gu_err) \
- : "r"(ptr), "1"(__gu_err));
+ : "r"(ptr), "1"(__gu_err)); \
+ \
+ (val) = (__force __typeof__(*(ptr))) __gu_val; \
+}

#if !defined(CONFIG_64BIT)

-#define __get_user_asm64(ptr) \
+#define __get_user_asm64(val, ptr) \
+{ \
+ union { \
+ unsigned long long l; \
+ __typeof__(*(ptr)) t; \
+ } __gu_tmp; \
+ \
__asm__(" copy %%r0,%R0\n" \
"1: ldw 0(%%sr2,%2),%0\n" \
"2: ldw 4(%%sr2,%2),%R0\n" \
"9:\n" \
ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 9b) \
ASM_EXCEPTIONTABLE_ENTRY_EFAULT(2b, 9b) \
- : "=r"(__gu_val), "=r"(__gu_err) \
- : "r"(ptr), "1"(__gu_err));
+ : "=&r"(__gu_tmp.l), "=r"(__gu_err) \
+ : "r"(ptr), "1"(__gu_err)); \
+ \
+ (val) = __gu_tmp.t; \
+}

#endif /* !defined(CONFIG_64BIT) */

-#define __put_user(x, ptr) \
+#define __put_user_internal(x, ptr) \
({ \
register long __pu_err __asm__ ("r8") = 0; \
__typeof__(*(ptr)) __x = (__typeof__(*(ptr)))(x); \
\
- load_sr2(); \
switch (sizeof(*(ptr))) { \
- case 1: __put_user_asm("stb", __x, ptr); break; \
- case 2: __put_user_asm("sth", __x, ptr); break; \
- case 4: __put_user_asm("stw", __x, ptr); break; \
- case 8: STD_USER(__x, ptr); break; \
- default: BUILD_BUG(); break; \
- } \
+ case 1: __put_user_asm("stb", __x, ptr); break; \
+ case 2: __put_user_asm("sth", __x, ptr); break; \
+ case 4: __put_user_asm("stw", __x, ptr); break; \
+ case 8: STD_USER(__x, ptr); break; \
+ default: BUILD_BUG(); \
+ } \
\
__pu_err; \
})

+#define __put_user(x, ptr) \
+({ \
+ load_sr2(); \
+ __put_user_internal(x, ptr); \
+})
+
+
/*
* The "__put_user/kernel_asm()" macros tell gcc they read from memory
* instead of writing. This is because they do not write to any memory