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Date:   Tue, 09 Feb 2021 11:29:15 +1000
From:   Nicholas Piggin <npiggin@gmail.com>
Subject: Re: [PATCH v5 10/22] powerpc/syscall: Use is_compat_task()
To:     Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Christophe Leroy <christophe.leroy@csgroup.eu>,
        Michael Ellerman <mpe@ellerman.id.au>, msuchanek@suse.de,
        Paul Mackerras <paulus@samba.org>
Cc:     linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
References: <cover.1612796617.git.christophe.leroy@csgroup.eu>
        <c8094662199337a7200fea9f6e1d1f8b1b6d5f69.1612796617.git.christophe.leroy@csgroup.eu>
In-Reply-To: <c8094662199337a7200fea9f6e1d1f8b1b6d5f69.1612796617.git.christophe.leroy@csgroup.eu>
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Excerpts from Christophe Leroy's message of February 9, 2021 1:10 am:
> Instead of hard comparing task flags with _TIF_32BIT, use
> is_compat_task(). The advantage is that it returns 0 on PPC32
> allthough _TIF_32BIT is always set.
>=20
> Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>

Reviewed-by: Nicholas Piggin <npiggin@gmail.com>


> ---
>  arch/powerpc/kernel/interrupt.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>=20
> diff --git a/arch/powerpc/kernel/interrupt.c b/arch/powerpc/kernel/interr=
upt.c
> index 2dac4d2bb1cf..46fd195ca659 100644
> --- a/arch/powerpc/kernel/interrupt.c
> +++ b/arch/powerpc/kernel/interrupt.c
> @@ -2,6 +2,8 @@
> =20
>  #include <linux/context_tracking.h>
>  #include <linux/err.h>
> +#include <linux/compat.h>
> +
>  #include <asm/asm-prototypes.h>
>  #include <asm/kup.h>
>  #include <asm/cputime.h>
> @@ -118,7 +120,7 @@ notrace long system_call_exception(long r3, long r4, =
long r5,
>  	/* May be faster to do array_index_nospec? */
>  	barrier_nospec();
> =20
> -	if (unlikely(is_32bit_task())) {
> +	if (unlikely(is_compat_task())) {
>  		f =3D (void *)compat_sys_call_table[r0];
> =20
>  		r3 &=3D 0x00000000ffffffffULL;
> --=20
> 2.25.0
>=20
>=20