diff options
| -rw-r--r-- | linux-user/qemu.h | 63 |
1 files changed, 33 insertions, 30 deletions
diff --git a/linux-user/qemu.h b/linux-user/qemu.h index 8a3538c631..31a220af81 100644 --- a/linux-user/qemu.h +++ b/linux-user/qemu.h @@ -287,36 +287,39 @@ static inline int access_ok(int type, abi_ulong addr, abi_ulong size) (type == VERIFY_READ) ? PAGE_READ : (PAGE_READ | PAGE_WRITE)) == 0; } -/* NOTE __get_user and __put_user use host pointers and don't check access. */ -/* 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)\ -({ __typeof(*hptr) pu_ = (x);\ - switch(sizeof(*hptr)) {\ - case 1: break;\ - case 2: pu_ = tswap16(pu_); break; \ - case 4: pu_ = tswap32(pu_); break; \ - case 8: pu_ = tswap64(pu_); break; \ - default: abort();\ - }\ - memcpy(hptr, &pu_, sizeof(pu_)); \ - 0;\ -}) - -#define __get_user(x, hptr) \ -({ __typeof(*hptr) gu_; \ - memcpy(&gu_, hptr, sizeof(gu_)); \ - switch(sizeof(*hptr)) {\ - case 1: break; \ - case 2: gu_ = tswap16(gu_); break; \ - case 4: gu_ = tswap32(gu_); break; \ - case 8: gu_ = tswap64(gu_); break; \ - default: abort();\ - }\ - (x) = gu_; \ - 0;\ -}) +/* NOTE __get_user and __put_user use host pointers and don't check access. + These are usually used to access struct data members once the struct has + been locked - usually with lock_user_struct. */ + +/* Tricky points: + - Use __builtin_choose_expr to avoid type promotion from ?:, + - Invalid sizes result in a compile time error stemming from + the fact that abort has no parameters. + - It's easier to use the endian-specific unaligned load/store + functions than host-endian unaligned load/store plus tswapN. */ + +#define __put_user_e(x, hptr, e) \ + (__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)), 0) + +#define __get_user_e(x, hptr, e) \ + ((x) = \ + __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), 0) + +#ifdef TARGET_WORDS_BIGENDIAN +# 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 */ /* These are usually used to access an atomic data type, such as an int, |