[PATCH v3 03/32] Update the definitions of __put_user and __get_user macros

[Karim Taha <kariem.taha2.7@gmail.com>]

From: Warner Losh <imp@bsdimp.com>

Use __builtin_choose_expr to avoid type promotion from ?:
in __put_user_e and __get_user_e macros.
Copied from linux-user/qemu.h, originally by Blue Swirl.

Signed-off-by: Warner Losh <imp@bsdimp.com>
Signed-off-by: Karim Taha <kariem.taha2.7@gmail.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 bsd-user/qemu.h   | 81 ++++++++++++++++++++---------------------------
 bsd-user/signal.c |  5 +--
 2 files changed, 35 insertions(+), 51 deletions(-)

diff --git a/bsd-user/qemu.h b/bsd-user/qemu.h
index edf9602f9b..656f38db56 100644
--- a/bsd-user/qemu.h
+++ b/bsd-user/qemu.h
@@ -276,50 +276,37 @@ static inline bool access_ok(int type, abi_ulong addr, abi_ulong size)
  * These are usually used to access struct data members once the struct has been
  * locked - usually with lock_user_struct().
  */
-#define __put_user(x, hptr)\
-({\
-    int size = sizeof(*hptr);\
-    switch (size) {\
-    case 1:\
-        *(uint8_t *)(hptr) = (uint8_t)(typeof(*hptr))(x);\
-        break;\
-    case 2:\
-        *(uint16_t *)(hptr) = tswap16((typeof(*hptr))(x));\
-        break;\
-    case 4:\
-        *(uint32_t *)(hptr) = tswap32((typeof(*hptr))(x));\
-        break;\
-    case 8:\
-        *(uint64_t *)(hptr) = tswap64((typeof(*hptr))(x));\
-        break;\
-    default:\
-        abort();\
-    } \
-    0;\
-})
+#define __put_user_e(x, hptr, e)                                            \
+    do {                                                                    \
+        PRAGMA_DISABLE_PACKED_WARNING;                                      \
+        (__builtin_choose_expr(sizeof(*(hptr)) == 1, stb_p,                 \
+        __builtin_choose_expr(sizeof(*(hptr)) == 2, stw_##e##_p,            \
+        __builtin_choose_expr(sizeof(*(hptr)) == 4, stl_##e##_p,            \
+        __builtin_choose_expr(sizeof(*(hptr)) == 8, stq_##e##_p, abort))))  \
+            ((hptr), (x)), (void)0);                                        \
+        PRAGMA_REENABLE_PACKED_WARNING;                                     \
+    } while (0)
+
+#define __get_user_e(x, hptr, e)                                            \
+    do {                                                                    \
+        PRAGMA_DISABLE_PACKED_WARNING;                                      \
+        ((x) = (typeof(*hptr))(                                             \
+        __builtin_choose_expr(sizeof(*(hptr)) == 1, ldub_p,                 \
+        __builtin_choose_expr(sizeof(*(hptr)) == 2, lduw_##e##_p,           \
+        __builtin_choose_expr(sizeof(*(hptr)) == 4, ldl_##e##_p,            \
+        __builtin_choose_expr(sizeof(*(hptr)) == 8, ldq_##e##_p, abort))))  \
+            (hptr)), (void)0);                                              \
+        PRAGMA_REENABLE_PACKED_WARNING;                                     \
+    } while (0)
 
-#define __get_user(x, hptr) \
-({\
-    int size = sizeof(*hptr);\
-    switch (size) {\
-    case 1:\
-        x = (typeof(*hptr))*(uint8_t *)(hptr);\
-        break;\
-    case 2:\
-        x = (typeof(*hptr))tswap16(*(uint16_t *)(hptr));\
-        break;\
-    case 4:\
-        x = (typeof(*hptr))tswap32(*(uint32_t *)(hptr));\
-        break;\
-    case 8:\
-        x = (typeof(*hptr))tswap64(*(uint64_t *)(hptr));\
-        break;\
-    default:\
-        x = 0;\
-        abort();\
-    } \
-    0;\
-})
+
+#if TARGET_BIG_ENDIAN
+# define __put_user(x, hptr)  __put_user_e(x, hptr, be)
+# define __get_user(x, hptr)  __get_user_e(x, hptr, be)
+#else
+# define __put_user(x, hptr)  __put_user_e(x, hptr, le)
+# define __get_user(x, hptr)  __get_user_e(x, hptr, le)
+#endif
 
 /*
  * put_user()/get_user() take a guest address and check access
@@ -332,10 +319,10 @@ static inline bool access_ok(int type, abi_ulong addr, abi_ulong size)
 ({                                                                      \
     abi_ulong __gaddr = (gaddr);                                        \
     target_type *__hptr;                                                \
-    abi_long __ret;                                                     \
+    abi_long __ret = 0;                                                 \
     __hptr = lock_user(VERIFY_WRITE, __gaddr, sizeof(target_type), 0);  \
     if (__hptr) {                                                       \
-        __ret = __put_user((x), __hptr);                                \
+        __put_user((x), __hptr);                                        \
         unlock_user(__hptr, __gaddr, sizeof(target_type));              \
     } else                                                              \
         __ret = -TARGET_EFAULT;                                         \
@@ -346,10 +333,10 @@ static inline bool access_ok(int type, abi_ulong addr, abi_ulong size)
 ({                                                                      \
     abi_ulong __gaddr = (gaddr);                                        \
     target_type *__hptr;                                                \
-    abi_long __ret;                                                     \
+    abi_long __ret = 0;                                                 \
     __hptr = lock_user(VERIFY_READ, __gaddr, sizeof(target_type), 1);   \
     if (__hptr) {                                                       \
-        __ret = __get_user((x), __hptr);                                \
+        __get_user((x), __hptr);                                        \
         unlock_user(__hptr, __gaddr, 0);                                \
     } else {                                                            \
         (x) = 0;                                                        \
diff --git a/bsd-user/signal.c b/bsd-user/signal.c
index f4e078ee1d..4db85a3485 100644
--- a/bsd-user/signal.c
+++ b/bsd-user/signal.c
@@ -787,10 +787,7 @@ static int reset_signal_mask(target_ucontext_t *ucontext)
     TaskState *ts = (TaskState *)thread_cpu->opaque;
 
     for (i = 0; i < TARGET_NSIG_WORDS; i++) {
-        if (__get_user(target_set.__bits[i],
-                    &ucontext->uc_sigmask.__bits[i])) {
-            return -TARGET_EFAULT;
-        }
+        __get_user(target_set.__bits[i], &ucontext->uc_sigmask.__bits[i]);
     }
     target_to_host_sigset_internal(&blocked, &target_set);
     ts->signal_mask = blocked;
-- 
2.40.0