diff options
| author | Richard Henderson <rth@twiddle.net> | 2012-03-24 21:31:25 +0100 |
|---|---|---|
| committer | Richard Henderson <rth@twiddle.net> | 2012-09-21 22:02:15 +0200 |
| commit | 62724cc5ebd7fb9113f156cbc0d2bb5e3cb0a9ae (patch) | |
| tree | 264a6d37e963318a07ab782c7aea863c7578167e /linux-user | |
| parent | cfb75cb9807463ebe18b127096b48b5d0db1ce03 (diff) | |
linux-user: Use memcpy in get_user/put_user.
When host and target have differing alignment rules, using a cast
and direct memory operation can result in SIGBUS. Use memcpy instead,
which the compiler will happily optimize when alignment is satisfied.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Diffstat (limited to 'linux-user')
| -rw-r--r-- | linux-user/qemu.h | 47 |
1 files changed, 15 insertions, 32 deletions
diff --git a/linux-user/qemu.h b/linux-user/qemu.h index 69b27d7146..fc4cc00b9f 100644 --- a/linux-user/qemu.h +++ b/linux-user/qemu.h @@ -289,46 +289,29 @@ static inline int access_ok(int type, abi_ulong addr, abi_ulong size) * struct has been locked - usually with lock_user_struct(). */ #define __put_user(x, hptr)\ -({\ +({ __typeof(*hptr) pu_ = (x);\ switch(sizeof(*hptr)) {\ - case 1:\ - *(uint8_t *)(hptr) = (uint8_t)(typeof(*hptr))(x);\ - break;\ - case 2:\ - *(uint16_t *)(hptr) = tswap16((uint16_t)(typeof(*hptr))(x));\ - break;\ - case 4:\ - *(uint32_t *)(hptr) = tswap32((uint32_t)(typeof(*hptr))(x));\ - break;\ - case 8:\ - *(uint64_t *)(hptr) = tswap64((typeof(*hptr))(x));\ - break;\ - default:\ - abort();\ + 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:\ - 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:\ - /* avoid warning */\ - x = 0;\ - abort();\ + 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;\ }) |