linux-kernel - Re: [PATCH] powerpc/603: Fix boot failure with DEBUG

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <abe73aa3-8f4e-45a1-033f-428fd67a7570@csgroup.eu>
Date:   Wed, 19 Jan 2022 11:19:06 +0000
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Michael Ellerman <mpe@...erman.id.au>
CC:     Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Paul Mackerras <paulus@...ba.org>,
        "linuxppc-dev@...ts.ozlabs.org" <linuxppc-dev@...ts.ozlabs.org>,
        Maxime Bizon <mbizon@...ebox.fr>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>
Subject: Re: [PATCH] powerpc/603: Fix boot failure with DEBUG_PAGEALLOC and
 KFENCE

Michael, ping.

Le 07/12/2021 à 07:10, Christophe Leroy a écrit :
> Allthough kernel text is always mapped with BATs, we still have
> inittext mapped with pages, so TLB miss handling is required
> when CONFIG_DEBUG_PAGEALLOC or CONFIG_KFENCE is set.
> 
> The final solution should be to set a BAT that also maps inittext
> but that BAT then needs to be cleared at end of init, and it will
> require more changes to be able to do it properly.
> 
> As DEBUG_PAGEALLOC or KFENCE are debugging, performance is not a big
> deal so let's fix it simply for now to enable easy stable application.
> 
> Reported-by: Maxime Bizon <mbizon@...ebox.fr>
> Fixes: 035b19a15a98 ("powerpc/32s: Always map kernel text and rodata with BATs")
> Cc: stable@...r.kernel.org
> Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
> ---
>   arch/powerpc/kernel/head_book3s_32.S | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/head_book3s_32.S b/arch/powerpc/kernel/head_book3s_32.S
> index 68e5c0a7e99d..2e2a8211b17b 100644
> --- a/arch/powerpc/kernel/head_book3s_32.S
> +++ b/arch/powerpc/kernel/head_book3s_32.S
> @@ -421,14 +421,14 @@ InstructionTLBMiss:
>    */
>   	/* Get PTE (linux-style) and check access */
>   	mfspr	r3,SPRN_IMISS
> -#ifdef CONFIG_MODULES
> +#if defined(CONFIG_MODULES) || defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KFENCE)
>   	lis	r1, TASK_SIZE@h		/* check if kernel address */
>   	cmplw	0,r1,r3
>   #endif
>   	mfspr	r2, SPRN_SDR1
>   	li	r1,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC | _PAGE_USER
>   	rlwinm	r2, r2, 28, 0xfffff000
> -#ifdef CONFIG_MODULES
> +#if defined(CONFIG_MODULES) || defined(CONFIG_DEBUG_PAGEALLOC) || defined(CONFIG_KFENCE)
>   	bgt-	112f
>   	lis	r2, (swapper_pg_dir - PAGE_OFFSET)@ha	/* if kernel address, use */
>   	li	r1,_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_EXEC