From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:57456) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TFF5p-0005C9-HW for qemu-devel@nongnu.org; Fri, 21 Sep 2012 22:05:20 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TFF5o-0000dg-3k for qemu-devel@nongnu.org; Fri, 21 Sep 2012 22:05:17 -0400 Received: from mail-pb0-f45.google.com ([209.85.160.45]:64906) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TFF5n-0000d7-T8 for qemu-devel@nongnu.org; Fri, 21 Sep 2012 22:05:16 -0400 Received: by pbbrp12 with SMTP id rp12so8850169pbb.4 for ; Fri, 21 Sep 2012 19:05:15 -0700 (PDT) Sender: Richard Henderson From: Richard Henderson Date: Fri, 21 Sep 2012 19:04:54 -0700 Message-Id: <1348279507-3617-2-git-send-email-rth@twiddle.net> In-Reply-To: <1348279507-3617-1-git-send-email-rth@twiddle.net> References: <1348279507-3617-1-git-send-email-rth@twiddle.net> Subject: [Qemu-devel] [PATCH 01/14] linux-user: Use memcpy in get_user/put_user. List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Blue Swirl 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 Reviewed-by: Peter Maydell --- linux-user/qemu.h | 47 +++++++++++++++-------------------------------- 1 file changed, 15 insertions(+), 32 deletions(-) diff --git a/linux-user/qemu.h b/linux-user/qemu.h index 69b27d7..fc4cc00 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;\ }) -- 1.7.11.4