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target/i386: Inline cmpxchg8b 

Use tcg_gen_atomic_cmpxchg_i64 for the atomic case,
and tcg_gen_nonatomic_cmpxchg_i64 otherwise.

Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
This commit is contained in:
Richard Henderson 2022-11-09 15:59:03 +11:00
parent 6218c177af
commit 326ad06cf5
3 changed files with 49 additions and 64 deletions
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2
target/i386/helper.h
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@ -66,8 +66,6 @@ DEF_HELPER_1(rsm, void, env)
#endif /* !CONFIG_USER_ONLY */
DEF_HELPER_2(into, void, env, int)
DEF_HELPER_2(cmpxchg8b_unlocked, void, env, tl)
DEF_HELPER_2(cmpxchg8b, void, env, tl)
#ifdef TARGET_X86_64
DEF_HELPER_2(cmpxchg16b_unlocked, void, env, tl)
DEF_HELPER_2(cmpxchg16b, void, env, tl)

57
target/i386/tcg/mem_helper.c
View File

@ -27,63 +27,6 @@
#include "tcg/tcg.h"
#include "helper-tcg.h"
void helper_cmpxchg8b_unlocked(CPUX86State *env, target_ulong a0)
{
uintptr_t ra = GETPC();
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]);
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 {
env->regs[R_EAX] = (uint32_t)oldv;
env->regs[R_EDX] = (uint32_t)(oldv >> 32);
eflags &= ~CC_Z;
}
CC_SRC = eflags;
}
void helper_cmpxchg8b(CPUX86State *env, target_ulong a0)
{
#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]);
{
uintptr_t ra = GETPC();
int mem_idx = cpu_mmu_index(env, false);
MemOpIdx oi = make_memop_idx(MO_TEUQ, mem_idx);
oldv = cpu_atomic_cmpxchgq_le_mmu(env, a0, cmpv, newv, oi, ra);
}
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_cpu(env), GETPC());
#endif /* CONFIG_ATOMIC64 */
}
#ifdef TARGET_X86_64
void helper_cmpxchg16b_unlocked(CPUX86State *env, target_ulong a0)
{

54
target/i386/tcg/translate.c
View File

@ -2995,15 +2995,59 @@ static void gen_sty_env_A0(DisasContext *s, int offset, bool align)
static void gen_cmpxchg8b(DisasContext *s, CPUX86State *env, int modrm)
{
TCGv_i64 cmp, val, old;
TCGv Z;
gen_lea_modrm(env, s, modrm);
if ((s->prefix & PREFIX_LOCK) &&
(tb_cflags(s->base.tb) & CF_PARALLEL)) {
gen_helper_cmpxchg8b(cpu_env, s->A0);
cmp = tcg_temp_new_i64();
val = tcg_temp_new_i64();
old = tcg_temp_new_i64();
/* Construct the comparison values from the register pair. */
tcg_gen_concat_tl_i64(cmp, cpu_regs[R_EAX], cpu_regs[R_EDX]);
tcg_gen_concat_tl_i64(val, cpu_regs[R_EBX], cpu_regs[R_ECX]);
/* Only require atomic with LOCK; non-parallel handled in generator. */
if (s->prefix & PREFIX_LOCK) {
tcg_gen_atomic_cmpxchg_i64(old, s->A0, cmp, val, s->mem_index, MO_TEUQ);
} else {
gen_helper_cmpxchg8b_unlocked(cpu_env, s->A0);
tcg_gen_nonatomic_cmpxchg_i64(old, s->A0, cmp, val,
s->mem_index, MO_TEUQ);
}
set_cc_op(s, CC_OP_EFLAGS);
tcg_temp_free_i64(val);
/* Set tmp0 to match the required value of Z. */
tcg_gen_setcond_i64(TCG_COND_EQ, cmp, old, cmp);
Z = tcg_temp_new();
tcg_gen_trunc_i64_tl(Z, cmp);
tcg_temp_free_i64(cmp);
/*
* Extract the result values for the register pair.
* For 32-bit, we may do this unconditionally, because on success (Z=1),
* the old value matches the previous value in EDX:EAX. For x86_64,
* the store must be conditional, because we must leave the source
* registers unchanged on success, and zero-extend the writeback
* on failure (Z=0).
*/
if (TARGET_LONG_BITS == 32) {
tcg_gen_extr_i64_tl(cpu_regs[R_EAX], cpu_regs[R_EDX], old);
} else {
TCGv zero = tcg_constant_tl(0);
tcg_gen_extr_i64_tl(s->T0, s->T1, old);
tcg_gen_movcond_tl(TCG_COND_EQ, cpu_regs[R_EAX], Z, zero,
s->T0, cpu_regs[R_EAX]);
tcg_gen_movcond_tl(TCG_COND_EQ, cpu_regs[R_EDX], Z, zero,
s->T1, cpu_regs[R_EDX]);
}
tcg_temp_free_i64(old);
/* Update Z. */
gen_compute_eflags(s);
tcg_gen_deposit_tl(cpu_cc_src, cpu_cc_src, Z, ctz32(CC_Z), 1);
tcg_temp_free(Z);
}
#ifdef TARGET_X86_64