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From:   Michael Ellerman <mpe@ellerman.id.au>
To:     Christophe Leroy <christophe.leroy@c-s.fr>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
        Paul Mackerras <paulus@samba.org>, dja@axtens.net
Cc:     linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
        linux-mm@kvack.org
Subject: Re: [PATCH v5 17/17] powerpc/32s: Enable CONFIG_VMAP_STACK
In-Reply-To: <2e2509a242fd5f3e23df4a06530c18060c4d321e.1576916812.git.christophe.leroy@c-s.fr>
References: <cover.1576916812.git.christophe.leroy@c-s.fr> <2e2509a242fd5f3e23df4a06530c18060c4d321e.1576916812.git.christophe.leroy@c-s.fr>
Date:   Sat, 18 Jan 2020 22:46:13 +1000
Message-ID: <87zhel6iga.fsf@mpe.ellerman.id.au>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Christophe Leroy <christophe.leroy@c-s.fr> writes:
> diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
> index 90ef355e958b..3be041166db4 100644
> --- a/arch/powerpc/kernel/head_32.S
> +++ b/arch/powerpc/kernel/head_32.S
> @@ -272,14 +272,20 @@ __secondary_hold_acknowledge:
>   */
>  	. = 0x200
>  	DO_KVM  0x200
> +MachineCheck:
>  	EXCEPTION_PROLOG_0
> +#ifdef CONFIG_VMAP_STACK
> +	li	r11, MSR_KERNEL & ~(MSR_IR | MSR_RI) /* can take DTLB miss */
> +	mtmsr	r11
> +#endif
>  #ifdef CONFIG_PPC_CHRP
>  	mfspr	r11, SPRN_SPRG_THREAD
> +	tovirt_vmstack(r11, r11)

This didn't build:

    arch/powerpc/kernel/head_32.S:283: Error: syntax error; found `r', expected `,'
    arch/powerpc/kernel/head_32.S:283: Error: found 'r', expected: ')'
    arch/powerpc/kernel/head_32.S:283: Error: bad expression
    arch/powerpc/kernel/head_32.S:283: Error: junk at end of line: `r11,%r11),0xc0000000@h'


I fixed it by dropping the brackets.

cheers