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From: Scott Wood <oss@buserror.net>
To: Jason Yan <yanaijie@huawei.com>,
	mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org,
	diana.craciun@nxp.com, christophe.leroy@c-s.fr,
	benh@kernel.crashing.org, paulus@samba.org, npiggin@gmail.com,
	keescook@chromium.org, kernel-hardening@lists.openwall.com
Cc: linux-kernel@vger.kernel.org, zhaohongjiang@huawei.com
Subject: Re: [PATCH v3 4/6] powerpc/fsl_booke/64: do not clear the BSS for the second pass
Date: Wed, 04 Mar 2020 15:49:21 -0600	[thread overview]
Message-ID: <feda5c76f134b415d2f43b99b8d6880b9b4b1750.camel@buserror.net> (raw)
In-Reply-To: <20200206025825.22934-5-yanaijie@huawei.com>

On Thu, 2020-02-06 at 10:58 +0800, Jason Yan wrote:
> The BSS section has already cleared out in the first pass. No need to
> clear it again. This can save some time when booting with KASLR
> enabled.
> 
> Signed-off-by: Jason Yan <yanaijie@huawei.com>
> Cc: Scott Wood <oss@buserror.net>
> Cc: Diana Craciun <diana.craciun@nxp.com>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Christophe Leroy <christophe.leroy@c-s.fr>
> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Nicholas Piggin <npiggin@gmail.com>
> Cc: Kees Cook <keescook@chromium.org>
> ---
>  arch/powerpc/kernel/head_64.S | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S
> index 744624140fb8..8c644e7c3eaf 100644
> --- a/arch/powerpc/kernel/head_64.S
> +++ b/arch/powerpc/kernel/head_64.S
> @@ -914,6 +914,13 @@ start_here_multiplatform:
>  	bl      relative_toc
>  	tovirt(r2,r2)
>  
> +	/* Do not clear the BSS for the second pass if randomized */
> +	LOAD_REG_ADDR(r3, kernstart_virt_addr)
> +	lwz     r3,0(r3)
> +	LOAD_REG_IMMEDIATE(r4, KERNELBASE)
> +	cmpw	r3,r4
> +	bne	4f

These are 64-bit values.

-Scott



  reply	other threads:[~2020-03-04 21:49 UTC|newest]

Thread overview: 82+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-06  2:58 [PATCH v3 0/6] implement KASLR for powerpc/fsl_booke/64 Jason Yan
2020-02-06  2:58 ` Jason Yan
2020-02-06  2:58 ` [PATCH v3 1/6] powerpc/fsl_booke/kaslr: refactor kaslr_legal_offset() and kaslr_early_init() Jason Yan
2020-02-06  2:58   ` Jason Yan
2020-02-20 13:40   ` Christophe Leroy
2020-02-26  2:11     ` Jason Yan
2020-02-26  2:11       ` Jason Yan
2020-02-06  2:58 ` [PATCH v3 2/6] powerpc/fsl_booke/64: introduce reloc_kernel_entry() helper Jason Yan
2020-02-06  2:58   ` Jason Yan
2020-02-20 13:41   ` Christophe Leroy
2020-02-06  2:58 ` [PATCH v3 3/6] powerpc/fsl_booke/64: implement KASLR for fsl_booke64 Jason Yan
2020-02-06  2:58   ` Jason Yan
2020-02-20 13:48   ` Christophe Leroy
2020-02-26  2:40     ` Jason Yan
2020-02-26  2:40       ` Jason Yan
2020-02-26  3:33       ` Jason Yan
2020-02-26  3:33         ` Jason Yan
2020-02-26  5:04         ` [RFC PATCH] Use IS_ENABLED() instead of #ifdefs Christophe Leroy
2020-02-26  5:04           ` Christophe Leroy
2020-02-26  6:26           ` Jason Yan
2020-02-26  6:26             ` Jason Yan
2020-02-26  5:10         ` [PATCH v3 3/6] powerpc/fsl_booke/64: implement KASLR for fsl_booke64 Christophe Leroy
2020-02-26  5:08       ` Christophe Leroy
2020-03-04 21:44   ` Scott Wood
2020-03-04 21:44     ` Scott Wood
2020-03-05  2:32     ` Jason Yan
2020-03-05  2:32       ` Jason Yan
2020-02-06  2:58 ` [PATCH v3 4/6] powerpc/fsl_booke/64: do not clear the BSS for the second pass Jason Yan
2020-02-06  2:58   ` Jason Yan
2020-03-04 21:49   ` Scott Wood [this message]
2020-03-04 21:49     ` Scott Wood
2020-03-05  3:14     ` Jason Yan
2020-03-05  3:14       ` Jason Yan
2020-02-06  2:58 ` [PATCH v3 5/6] powerpc/fsl_booke/64: clear the original kernel if randomized Jason Yan
2020-02-06  2:58   ` Jason Yan
2020-02-20 13:49   ` Christophe Leroy
2020-02-26  2:44     ` Jason Yan
2020-02-26  2:44       ` Jason Yan
2020-03-04 21:53   ` Scott Wood
2020-03-04 21:53     ` Scott Wood
2020-03-05  3:20     ` Jason Yan
2020-03-05  3:20       ` Jason Yan
2020-02-06  2:58 ` [PATCH v3 6/6] powerpc/fsl_booke/kaslr: rename kaslr-booke32.rst to kaslr-booke.rst and add 64bit part Jason Yan
2020-02-06  2:58   ` Jason Yan
2020-02-20 13:50   ` Christophe Leroy
2020-02-26  2:46     ` Jason Yan
2020-02-26  2:46       ` Jason Yan
2020-02-13  3:00 ` [PATCH v3 0/6] implement KASLR for powerpc/fsl_booke/64 Jason Yan
2020-02-13  3:00   ` Jason Yan
2020-02-20  3:33   ` Jason Yan
2020-02-20  3:33     ` Jason Yan
2020-02-26  7:16 ` Daniel Axtens
2020-02-26  7:16   ` Daniel Axtens
2020-02-26  8:18   ` Jason Yan
2020-02-26  8:18     ` Jason Yan
2020-02-26 11:41     ` Daniel Axtens
2020-02-27  1:55       ` Jason Yan
2020-02-27  1:55         ` Jason Yan
2020-02-28  5:53     ` Scott Wood
2020-02-28  5:53       ` Scott Wood
2020-02-28  6:47       ` Jason Yan
2020-02-28  6:47         ` Jason Yan
2020-02-29  4:28         ` Scott Wood
2020-02-29  4:28           ` Scott Wood
2020-02-29  7:27           ` Jason Yan
2020-02-29  7:27             ` Jason Yan
2020-02-29 22:54             ` Scott Wood
2020-02-29 22:54               ` Scott Wood
2020-03-02  2:17               ` Jason Yan
2020-03-02  2:17                 ` Jason Yan
2020-03-02  3:24                 ` Scott Wood
2020-03-02  3:24                   ` Scott Wood
2020-03-02  7:12                   ` Jason Yan
2020-03-02  7:12                     ` Jason Yan
2020-03-02  8:47                     ` Scott Wood
2020-03-02  8:47                       ` Scott Wood
2020-03-02  9:37                       ` Jason Yan
2020-03-02  9:37                         ` Jason Yan
2020-03-04 21:21   ` Scott Wood
2020-03-04 21:21     ` Scott Wood
2020-03-05  3:22     ` Jason Yan
2020-03-05  3:22       ` Jason Yan

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