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linux-user: Use memcpy in get_user/put_user.

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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>
This commit is contained in:
Richard Henderson 2012-03-24 21:31:25 +01:00
parent cfb75cb980
commit 62724cc5eb
1 changed files with 15 additions and 32 deletions
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47
linux-user/qemu.h
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@ -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;\
})