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From: Nicholas Piggin <npiggin@gmail.com>
To: Daniel Henrique Barboza <danielhb413@gmail.com>
Cc: Nicholas Piggin <npiggin@gmail.com>,
	Richard Henderson <richard.henderson@linaro.org>,
	qemu-ppc@nongnu.org, qemu-devel@nongnu.org,
	qemu-stable@nongnu.org
Subject: [PATCH 3/4] target/ppc: Remove larx/stcx. memory barrier semantics
Date: Sun,  4 Jun 2023 20:28:56 +1000	[thread overview]
Message-ID: <20230604102858.148584-3-npiggin@gmail.com> (raw)
In-Reply-To: <20230604102858.148584-1-npiggin@gmail.com>

larx and stcx. are not defined to order any memory operations.
Remove the barriers.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 target/ppc/translate.c | 11 -----------
 1 file changed, 11 deletions(-)

diff --git a/target/ppc/translate.c b/target/ppc/translate.c
index 5195047146..77e1c5abb6 100644
--- a/target/ppc/translate.c
+++ b/target/ppc/translate.c
@@ -3591,7 +3591,6 @@ static void gen_load_locked(DisasContext *ctx, MemOp memop)
     tcg_gen_movi_tl(cpu_reserve_size, memop_size(memop));
     tcg_gen_qemu_ld_tl(gpr, t0, ctx->mem_idx, memop | MO_ALIGN);
     tcg_gen_mov_tl(cpu_reserve_val, gpr);
-    tcg_gen_mb(TCG_MO_ALL | TCG_BAR_LDAQ);
 }
 
 #define LARX(name, memop)                  \
@@ -3835,11 +3834,6 @@ static void gen_conditional_store(DisasContext *ctx, MemOp memop)
 
     gen_set_label(l1);
 
-    /*
-     * Address mismatch implies failure.  But we still need to provide
-     * the memory barrier semantics of the instruction.
-     */
-    tcg_gen_mb(TCG_MO_ALL | TCG_BAR_STRL);
     tcg_gen_trunc_tl_i32(cpu_crf[0], cpu_so);
 
     gen_set_label(l2);
@@ -3943,11 +3937,6 @@ static void gen_stqcx_(DisasContext *ctx)
     tcg_gen_br(lab_over);
     gen_set_label(lab_fail);
 
-    /*
-     * Address mismatch implies failure.  But we still need to provide
-     * the memory barrier semantics of the instruction.
-     */
-    tcg_gen_mb(TCG_MO_ALL | TCG_BAR_STRL);
     tcg_gen_trunc_tl_i32(cpu_crf[0], cpu_so);
 
     gen_set_label(lab_over);
-- 
2.40.1



  parent reply	other threads:[~2023-06-04 10:30 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-06-04 10:28 [PATCH 1/4] target/ppc: Fix lqarx to set cpu_reserve Nicholas Piggin
2023-06-04 10:28 ` [PATCH 2/4] target/ppc: Ensure stcx size matches larx Nicholas Piggin
2023-06-04 16:58   ` Richard Henderson
2023-06-05  6:27   ` Nicholas Piggin
2023-06-19 15:48     ` Richard Henderson
2023-06-19 15:55       ` Peter Maydell
2023-06-19 17:02         ` Richard Henderson
2023-06-19 17:14           ` Peter Maydell
2023-06-20  3:39             ` Nicholas Piggin
2023-06-04 10:28 ` Nicholas Piggin [this message]
2023-06-04 16:12   ` [PATCH 3/4] target/ppc: Remove larx/stcx. memory barrier semantics Richard Henderson
2023-06-04 10:28 ` [PATCH 4/4] target/ppc: Rework store conditional to avoid branch Nicholas Piggin
2023-06-04 16:22   ` Richard Henderson
2023-06-04 16:05 ` [PATCH 1/4] target/ppc: Fix lqarx to set cpu_reserve Richard Henderson
2023-06-05  2:33   ` Nicholas Piggin

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