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tcg: Add atomic128 helpers

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Force the use of cmpxchg16b on x86_64.

Wikipedia suggests that only very old AMD64 (circa 2004) did not have
this instruction.  Further, it's required by Windows 8 so no new cpus
will ever omit it.

If we truely care about these, then we could check this at startup time
and then avoid executing paths that use it.

Reviewed-by: Emilio G. Cota <cota@braap.org>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
This commit is contained in:
Richard Henderson 2016-06-29 21:10:59 -07:00
parent c482cb117c
commit 7ebee43ee3
6 changed files with 119 additions and 3 deletions
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40
atomic_template.h
View File

@ -18,7 +18,11 @@
* License along with this library; if not, see <http://www.gnu.org/licenses/>.
*/
#if DATA_SIZE == 8
#if DATA_SIZE == 16
# define SUFFIX o
# define DATA_TYPE Int128
# define BSWAP bswap128
#elif DATA_SIZE == 8
# define SUFFIX q
# define DATA_TYPE uint64_t
# define BSWAP bswap64
@ -61,6 +65,21 @@ ABI_TYPE ATOMIC_NAME(cmpxchg)(CPUArchState *env, target_ulong addr,
return atomic_cmpxchg__nocheck(haddr, cmpv, newv);
}
#if DATA_SIZE >= 16
ABI_TYPE ATOMIC_NAME(ld)(CPUArchState *env, target_ulong addr EXTRA_ARGS)
{
DATA_TYPE val, *haddr = ATOMIC_MMU_LOOKUP;
__atomic_load(haddr, &val, __ATOMIC_RELAXED);
return val;
}
void ATOMIC_NAME(st)(CPUArchState *env, target_ulong addr,
ABI_TYPE val EXTRA_ARGS)
{
DATA_TYPE *haddr = ATOMIC_MMU_LOOKUP;
__atomic_store(haddr, &val, __ATOMIC_RELAXED);
}
#else
ABI_TYPE ATOMIC_NAME(xchg)(CPUArchState *env, target_ulong addr,
ABI_TYPE val EXTRA_ARGS)
{
@ -86,6 +105,8 @@ GEN_ATOMIC_HELPER(or_fetch)
GEN_ATOMIC_HELPER(xor_fetch)
#undef GEN_ATOMIC_HELPER
#endif /* DATA SIZE >= 16 */
#undef END
#if DATA_SIZE > 1
@ -105,6 +126,22 @@ ABI_TYPE ATOMIC_NAME(cmpxchg)(CPUArchState *env, target_ulong addr,
return BSWAP(atomic_cmpxchg__nocheck(haddr, BSWAP(cmpv), BSWAP(newv)));
}
#if DATA_SIZE >= 16
ABI_TYPE ATOMIC_NAME(ld)(CPUArchState *env, target_ulong addr EXTRA_ARGS)
{
DATA_TYPE val, *haddr = ATOMIC_MMU_LOOKUP;
__atomic_load(haddr, &val, __ATOMIC_RELAXED);
return BSWAP(val);
}
void ATOMIC_NAME(st)(CPUArchState *env, target_ulong addr,
ABI_TYPE val EXTRA_ARGS)
{
DATA_TYPE *haddr = ATOMIC_MMU_LOOKUP;
val = BSWAP(val);
__atomic_store(haddr, &val, __ATOMIC_RELAXED);
}
#else
ABI_TYPE ATOMIC_NAME(xchg)(CPUArchState *env, target_ulong addr,
ABI_TYPE val EXTRA_ARGS)
{
@ -166,6 +203,7 @@ ABI_TYPE ATOMIC_NAME(add_fetch)(CPUArchState *env, target_ulong addr,
ldo = ldn;
}
}
#endif /* DATA_SIZE >= 16 */
#undef END
#endif /* DATA_SIZE > 1 */

29
configure vendored
View File

@ -1216,7 +1216,10 @@ case "$cpu" in
cc_i386='$(CC) -m32'
;;
x86_64)
CPU_CFLAGS="-m64"
# ??? Only extremely old AMD cpus do not have cmpxchg16b.
# If we truly care, we should simply detect this case at
# runtime and generate the fallback to serial emulation.
CPU_CFLAGS="-m64 -mcx16"
LDFLAGS="-m64 $LDFLAGS"
cc_i386='$(CC) -m32'
;;
@ -4521,6 +4524,26 @@ if compile_prog "" "" ; then
int128=yes
fi
#########################################
# See if 128-bit atomic operations are supported.
atomic128=no
if test "$int128" = "yes"; then
cat > $TMPC << EOF
int main(void)
{
unsigned __int128 x = 0, y = 0;
y = __atomic_load_16(&x, 0);
__atomic_store_16(&x, y, 0);
__atomic_compare_exchange_16(&x, &y, x, 0, 0, 0);
return 0;
}
EOF
if compile_prog "" "" ; then
atomic128=yes
fi
fi
########################################
# check if getauxval is available.
@ -5483,6 +5506,10 @@ if test "$int128" = "yes" ; then
echo "CONFIG_INT128=y" >> $config_host_mak
fi
if test "$atomic128" = "yes" ; then
echo "CONFIG_ATOMIC128=y" >> $config_host_mak
fi
if test "$getauxval" = "yes" ; then
echo "CONFIG_GETAUXVAL=y" >> $config_host_mak
fi

5
cputlb.c
View File

@ -690,6 +690,11 @@ static void *atomic_mmu_lookup(CPUArchState *env, target_ulong addr,
#define DATA_SIZE 8
#include "atomic_template.h"
#ifdef CONFIG_ATOMIC128
#define DATA_SIZE 16
#include "atomic_template.h"
#endif
/* Second set of helpers are directly callable from TCG as helpers. */
#undef EXTRA_ARGS

6
include/qemu/int128.h
View File

@ -2,6 +2,7 @@
#define INT128_H
#ifdef CONFIG_INT128
#include "qemu/bswap.h"
typedef __int128_t Int128;
@ -137,6 +138,11 @@ static inline void int128_subfrom(Int128 *a, Int128 b)
*a -= b;
}
static inline Int128 bswap128(Int128 a)
{
return int128_make128(bswap64(int128_gethi(a)), bswap64(int128_getlo(a)));
}
#else /* !CONFIG_INT128 */
typedef struct Int128 Int128;

18
tcg-runtime.c
View File

@ -133,4 +133,22 @@ static void *atomic_mmu_lookup(CPUArchState *env, target_ulong addr,
#define DATA_SIZE 8
#include "atomic_template.h"
/* The following is only callable from other helpers, and matches up
with the softmmu version. */
#ifdef CONFIG_ATOMIC128
#undef EXTRA_ARGS
#undef ATOMIC_NAME
#undef ATOMIC_MMU_LOOKUP
#define EXTRA_ARGS , TCGMemOpIdx oi, uintptr_t retaddr
#define ATOMIC_NAME(X) \
HELPER(glue(glue(glue(atomic_ ## X, SUFFIX), END), _mmu))
#define ATOMIC_MMU_LOOKUP atomic_mmu_lookup(env, addr, DATA_SIZE, retaddr)
#define DATA_SIZE 16
#include "atomic_template.h"
#endif /* CONFIG_ATOMIC128 */
#endif /* !CONFIG_SOFTMMU */

24
tcg/tcg.h
View File

@ -1229,7 +1229,29 @@ GEN_ATOMIC_HELPER_ALL(xchg)
#undef GEN_ATOMIC_HELPER_ALL
#undef GEN_ATOMIC_HELPER
#endif /* CONFIG_SOFTMMU */
#ifdef CONFIG_ATOMIC128
#include "qemu/int128.h"
/* These aren't really a "proper" helpers because TCG cannot manage Int128.
However, use the same format as the others, for use by the backends. */
Int128 helper_atomic_cmpxchgo_le_mmu(CPUArchState *env, target_ulong addr,
Int128 cmpv, Int128 newv,
TCGMemOpIdx oi, uintptr_t retaddr);
Int128 helper_atomic_cmpxchgo_be_mmu(CPUArchState *env, target_ulong addr,
Int128 cmpv, Int128 newv,
TCGMemOpIdx oi, uintptr_t retaddr);
Int128 helper_atomic_ldo_le_mmu(CPUArchState *env, target_ulong addr,
TCGMemOpIdx oi, uintptr_t retaddr);
Int128 helper_atomic_ldo_be_mmu(CPUArchState *env, target_ulong addr,
TCGMemOpIdx oi, uintptr_t retaddr);
void helper_atomic_sto_le_mmu(CPUArchState *env, target_ulong addr, Int128 val,
TCGMemOpIdx oi, uintptr_t retaddr);
void helper_atomic_sto_be_mmu(CPUArchState *env, target_ulong addr, Int128 val,
TCGMemOpIdx oi, uintptr_t retaddr);
#endif /* CONFIG_ATOMIC128 */
#endif /* TCG_H */