From: Segher Boessenkool <segher@kernel.crashing.org>
To: Nicholas Piggin <npiggin@gmail.com>
Cc: linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH 1/2] powerpc/64s: Fix GENERIC_CPU build flags for PPC970 / G5
Date: Wed, 21 Sep 2022 13:50:31 -0500 [thread overview]
Message-ID: <20220921185031.GE25951@gate.crashing.org> (raw)
In-Reply-To: <20220921014103.587954-1-npiggin@gmail.com>
On Wed, Sep 21, 2022 at 11:41:02AM +1000, Nicholas Piggin wrote:
> Big-endian GENERIC_CPU supports 970, but builds with -mcpu=power5.
> POWER5 is ISA v2.02 whereas 970 is v2.01 plus Altivec. 2.02 added
> the popcntb instruction which a compiler might use.
>
> Use -mcpu=power4.
>
> Fixes: 471d7ff8b51b ("powerpc/64s: Remove POWER4 support")
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Segher Boessenkool <segher@kernel.crashing.org>
Thank you!
Maybe superfluous, but some more context: GCC's -mcpu=power4 means
POWER4+, ISA 2.01, according to our documentation. There is no
difference with ISA 2.00 (what plain POWER4 implements) for anything
GCC does.
Segher
next prev parent reply other threads:[~2022-09-21 18:53 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-21 1:41 [PATCH 1/2] powerpc/64s: Fix GENERIC_CPU build flags for PPC970 / G5 Nicholas Piggin
2022-09-21 1:41 ` [PATCH 2/2] powerpc/64s: update cpu selection options Nicholas Piggin
2022-09-21 19:03 ` Segher Boessenkool
2022-09-21 16:45 ` [PATCH 1/2] powerpc/64s: Fix GENERIC_CPU build flags for PPC970 / G5 Christophe Leroy
2022-09-21 18:50 ` Segher Boessenkool [this message]
2022-09-23 7:17 ` Nicholas Piggin
2022-09-23 12:22 ` Segher Boessenkool
2022-10-04 13:24 ` Michael Ellerman
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