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From: Nicholas Piggin <npiggin@gmail.com>
To: qemu-ppc@nongnu.org
Cc: Nicholas Piggin <npiggin@gmail.com>,
	qemu-devel@nongnu.org,
	Richard Henderson <richard.henderson@linaro.org>
Subject: [PATCH 2/4] tcg/ppc: ST_ST memory ordering is not provided with eieio
Date: Thu, 19 May 2022 23:59:06 +1000	[thread overview]
Message-ID: <20220519135908.21282-3-npiggin@gmail.com> (raw)
In-Reply-To: <20220519135908.21282-1-npiggin@gmail.com>

eieio does not provide ordering between stores to CI memory and stores
to cacheable memory so it can't be used as a general ST_ST barrier.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-of-by: Nicholas Piggin <npiggin@gmail.com>
---
 tcg/ppc/tcg-target.c.inc | 2 --
 1 file changed, 2 deletions(-)

diff --git a/tcg/ppc/tcg-target.c.inc b/tcg/ppc/tcg-target.c.inc
index cfcd121f9c..3ff845d063 100644
--- a/tcg/ppc/tcg-target.c.inc
+++ b/tcg/ppc/tcg-target.c.inc
@@ -1836,8 +1836,6 @@ static void tcg_out_mb(TCGContext *s, TCGArg a0)
     a0 &= TCG_MO_ALL;
     if (a0 == TCG_MO_LD_LD) {
         insn = LWSYNC;
-    } else if (a0 == TCG_MO_ST_ST) {
-        insn = EIEIO;
     }
     tcg_out32(s, insn);
 }
-- 
2.35.1



  parent reply	other threads:[~2022-05-19 14:06 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-19 13:59 [PATCH 0/4] ppc: improve some memory ordering issues Nicholas Piggin
2022-05-19 13:59 ` [PATCH 1/4] target/ppc: Fix eieio memory ordering semantics Nicholas Piggin
2022-05-19 15:30   ` Richard Henderson
2022-05-19 13:59 ` Nicholas Piggin [this message]
2022-05-19 13:59 ` [PATCH 3/4] tcg/ppc: Optimize memory ordering generation with lwsync Nicholas Piggin
2022-05-19 15:30   ` Richard Henderson
2022-05-19 13:59 ` [PATCH 4/4] target/ppc: Implement lwsync with weaker memory ordering Nicholas Piggin
2022-05-19 15:34   ` Richard Henderson
2022-05-23 19:24 ` [PATCH 0/4] ppc: improve some memory ordering issues Daniel Henrique Barboza

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