motorhead/qemu
1
0
Fork 0
mirror of https://github.com/Motorhead1991/qemu.git synced 2025-08-01 23:03:54 -06:00
Code Issues Projects Releases Packages Wiki Activity Actions

target-i386: emulate LOCK'ed cmpxchg using cmpxchg helpers

Browse source 
The diff here is uglier than necessary. All this does is to turn

FOO

into:

if (s->prefix & PREFIX_LOCK) {
  BAR
} else {
  FOO
}

where FOO is the original implementation of an unlocked cmpxchg.

[rth: Adjust unlocked cmpxchg to use movcond instead of branches.
Adjust helpers to use atomic helpers.]

Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-Id: <1467054136-10430-6-git-send-email-cota@braap.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
This commit is contained in:
Emilio G. Cota 2016-06-27 15:01:51 -04:00 • committed by Richard Henderson
parent 91682118aa
commit ae03f8de45
3 changed files with 170 additions and 67 deletions
Download patch file Download diff file Expand all files Collapse all files

138
target-i386/mem_helper.c
View file

@ -22,6 +22,8 @@
#include "exec/helper-proto.h"
#include "exec/exec-all.h"
#include "exec/cpu_ldst.h"
#include "qemu/int128.h"
#include "tcg.h"
/* broken thread support */
@ -56,53 +58,143 @@ void helper_lock_init(void)
}
#endif
void helper_cmpxchg8b(CPUX86State *env, target_ulong a0)
void helper_cmpxchg8b_unlocked(CPUX86State *env, target_ulong a0)
{
uint64_t d;
uintptr_t ra = GETPC();
uint64_t oldv, cmpv, newv;
int eflags;
eflags = cpu_cc_compute_all(env, CC_OP);
d = cpu_ldq_data_ra(env, a0, GETPC());
if (d == (((uint64_t)env->regs[R_EDX] << 32) | (uint32_t)env->regs[R_EAX])) {
cpu_stq_data_ra(env, a0, ((uint64_t)env->regs[R_ECX] << 32)
| (uint32_t)env->regs[R_EBX], GETPC());
cmpv = deposit64(env->regs[R_EAX], 32, 32, env->regs[R_EDX]);
newv = deposit64(env->regs[R_EBX], 32, 32, env->regs[R_ECX]);
oldv = cpu_ldq_data_ra(env, a0, ra);
newv = (cmpv == oldv ? newv : oldv);
/* always do the store */
cpu_stq_data_ra(env, a0, newv, ra);
if (oldv == cmpv) {
eflags |= CC_Z;
} else {
/* always do the store */
cpu_stq_data_ra(env, a0, d, GETPC());
env->regs[R_EDX] = (uint32_t)(d >> 32);
env->regs[R_EAX] = (uint32_t)d;
env->regs[R_EAX] = (uint32_t)oldv;
env->regs[R_EDX] = (uint32_t)(oldv >> 32);
eflags &= ~CC_Z;
}
CC_SRC = eflags;
}
#ifdef TARGET_X86_64
void helper_cmpxchg16b(CPUX86State *env, target_ulong a0)
void helper_cmpxchg8b(CPUX86State *env, target_ulong a0)
{
uint64_t d0, d1;
#ifdef CONFIG_ATOMIC64
uint64_t oldv, cmpv, newv;
int eflags;
eflags = cpu_cc_compute_all(env, CC_OP);
cmpv = deposit64(env->regs[R_EAX], 32, 32, env->regs[R_EDX]);
newv = deposit64(env->regs[R_EBX], 32, 32, env->regs[R_ECX]);
#ifdef CONFIG_USER_ONLY
{
uint64_t *haddr = g2h(a0);
cmpv = cpu_to_le64(cmpv);
newv = cpu_to_le64(newv);
oldv = atomic_cmpxchg__nocheck(haddr, cmpv, newv);
oldv = le64_to_cpu(oldv);
}
#else
{
uintptr_t ra = GETPC();
int mem_idx = cpu_mmu_index(env, false);
TCGMemOpIdx oi = make_memop_idx(MO_TEQ, mem_idx);
oldv = helper_atomic_cmpxchgq_le_mmu(env, a0, cmpv, newv, oi, ra);
}
#endif
if (oldv == cmpv) {
eflags |= CC_Z;
} else {
env->regs[R_EAX] = (uint32_t)oldv;
env->regs[R_EDX] = (uint32_t)(oldv >> 32);
eflags &= ~CC_Z;
}
CC_SRC = eflags;
#else
cpu_loop_exit_atomic(ENV_GET_CPU(env), GETPC());
#endif /* CONFIG_ATOMIC64 */
}
#ifdef TARGET_X86_64
void helper_cmpxchg16b_unlocked(CPUX86State *env, target_ulong a0)
{
uintptr_t ra = GETPC();
Int128 oldv, cmpv, newv;
uint64_t o0, o1;
int eflags;
bool success;
if ((a0 & 0xf) != 0) {
raise_exception_ra(env, EXCP0D_GPF, GETPC());
}
eflags = cpu_cc_compute_all(env, CC_OP);
d0 = cpu_ldq_data_ra(env, a0, GETPC());
d1 = cpu_ldq_data_ra(env, a0 + 8, GETPC());
if (d0 == env->regs[R_EAX] && d1 == env->regs[R_EDX]) {
cpu_stq_data_ra(env, a0, env->regs[R_EBX], GETPC());
cpu_stq_data_ra(env, a0 + 8, env->regs[R_ECX], GETPC());
cmpv = int128_make128(env->regs[R_EAX], env->regs[R_EDX]);
newv = int128_make128(env->regs[R_EBX], env->regs[R_ECX]);
o0 = cpu_ldq_data_ra(env, a0 + 0, ra);
o1 = cpu_ldq_data_ra(env, a0 + 8, ra);
oldv = int128_make128(o0, o1);
success = int128_eq(oldv, cmpv);
if (!success) {
newv = oldv;
}
cpu_stq_data_ra(env, a0 + 0, int128_getlo(newv), ra);
cpu_stq_data_ra(env, a0 + 8, int128_gethi(newv), ra);
if (success) {
eflags |= CC_Z;
} else {
/* always do the store */
cpu_stq_data_ra(env, a0, d0, GETPC());
cpu_stq_data_ra(env, a0 + 8, d1, GETPC());
env->regs[R_EDX] = d1;
env->regs[R_EAX] = d0;
env->regs[R_EAX] = int128_getlo(oldv);
env->regs[R_EDX] = int128_gethi(oldv);
eflags &= ~CC_Z;
}
CC_SRC = eflags;
}
void helper_cmpxchg16b(CPUX86State *env, target_ulong a0)
{
uintptr_t ra = GETPC();
if ((a0 & 0xf) != 0) {
raise_exception_ra(env, EXCP0D_GPF, ra);
} else {
#ifndef CONFIG_ATOMIC128
cpu_loop_exit_atomic(ENV_GET_CPU(env), ra);
#else
int eflags = cpu_cc_compute_all(env, CC_OP);
Int128 cmpv = int128_make128(env->regs[R_EAX], env->regs[R_EDX]);
Int128 newv = int128_make128(env->regs[R_EBX], env->regs[R_ECX]);
int mem_idx = cpu_mmu_index(env, false);
TCGMemOpIdx oi = make_memop_idx(MO_TEQ | MO_ALIGN_16, mem_idx);
Int128 oldv = helper_atomic_cmpxchgo_le_mmu(env, a0, cmpv,
newv, oi, ra);
if (int128_eq(oldv, cmpv)) {
eflags |= CC_Z;
} else {
env->regs[R_EAX] = int128_getlo(oldv);
env->regs[R_EDX] = int128_gethi(oldv);
eflags &= ~CC_Z;
}
CC_SRC = eflags;
#endif
}
}
#endif
void helper_boundw(CPUX86State *env, target_ulong a0, int v)