From: Segher Boessenkool <segher@kernel.crashing.org>
To: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Michael Ellerman <mpe@ellerman.id.au>,
Nicholas Piggin <npiggin@gmail.com>,
Madhavan Srinivasan <maddy@linux.ibm.com>,
linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2] powerpc/32: Fix unpaired stwcx. on interrupt exit
Date: Fri, 12 Sep 2025 08:24:31 -0500 [thread overview]
Message-ID: <aMQfD5M5yNmYxLho@gate> (raw)
In-Reply-To: <6040b5dbcf5cdaa1cd919fcf0790f12974ea6e5a.1757666244.git.christophe.leroy@csgroup.eu>
Hi!
On Fri, Sep 12, 2025 at 10:37:34AM +0200, Christophe Leroy wrote:
> BEGIN_FTR_SECTION
> + lwarx r0,0,r1
> +END_FTR_SECTION_IFSET(CPU_FTR_NEED_PAIRED_STWCX)
> stwcx. r0,0,r1 /* to clear the reservation */
> -FTR_SECTION_ELSE
> - lwarx r0,0,r1
> -ALT_FTR_SECTION_END_IFCLR(CPU_FTR_STCX_CHECKS_ADDRESS)
Hrm. So this is for V'ger (mpc7450)? What kind of issues does that
old thing have with unpaired larx/stcx., some performance impact?
The extra "dummy" larx has serious performance impact itself, on most
implementations (also on all newer stuff).
Segher
next prev parent reply other threads:[~2025-09-12 13:24 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-12 8:37 [PATCH v2] powerpc/32: Fix unpaired stwcx. on interrupt exit Christophe Leroy
2025-09-12 13:24 ` Segher Boessenkool [this message]
2025-09-12 13:34 ` Christophe Leroy
2025-11-21 2:53 ` Madhavan Srinivasan
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