[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-ID: <nycvar.YSQ.7.76.1709041215450.8603@knanqh.ubzr>
Date: Mon, 4 Sep 2017 12:19:10 -0400 (EDT)
From: Nicolas Pitre <nicolas.pitre@...aro.org>
To: Ard Biesheuvel <ard.biesheuvel@...aro.org>
cc: linux-arm-kernel@...ts.infradead.org, kernel-hardening@...ts.openwall.com,
Arnd Bergmann <arnd@...db.de>, Russell King <linux@...linux.org.uk>,
Kees Cook <keescook@...omium.org>, Thomas Garnier <thgarnie@...gle.com>,
Marc Zyngier <marc.zyngier@....com>, Mark Rutland <mark.rutland@....com>,
Tony Lindgren <tony@...mide.com>, Matt Fleming <matt@...eblueprint.co.uk>,
Dave Martin <dave.martin@....com>
Subject: Re: [PATCH v2 08/29] ARM: head: use PC-relative insn sequence for
__smp_alt
On Sun, 3 Sep 2017, Ard Biesheuvel wrote:
> Replace the open coded PC relative offset calculations with a pair
> of adr_l invocations. This ensures these quantities are invariant
> under runtime relocation.
You probably should add that this patch must be applied on top of "ARM:
kernel: use relative references for UP/SMP alternatives" because of the
expected r3 value prior to that patch.
Acked-by: Nicolas Pitre <nico@...aro.org>
> Cc: Russell King <linux@...linux.org.uk>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@...aro.org>
> ---
> arch/arm/kernel/head.S | 12 ++----------
> 1 file changed, 2 insertions(+), 10 deletions(-)
>
> diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S
> index ec22f42fd8bb..db6b823f20a4 100644
> --- a/arch/arm/kernel/head.S
> +++ b/arch/arm/kernel/head.S
> @@ -523,19 +523,11 @@ ARM_BE8(rev r0, r0) @ byteswap if big endian
> retne lr
>
> __fixup_smp_on_up:
> - adr r0, 1f
> - ldmia r0, {r3 - r5}
> - sub r3, r0, r3
> - add r4, r4, r3
> - add r5, r5, r3
> + adr_l r4, __smpalt_begin
> + adr_l r5, __smpalt_end
> b __do_fixup_smp_on_up
> ENDPROC(__fixup_smp)
>
> - .align
> -1: .word .
> - .word __smpalt_begin
> - .word __smpalt_end
> -
> .pushsection .data
> .globl smp_on_up
> smp_on_up:
> --
> 2.11.0
>
>
Powered by blists - more mailing lists
Confused about mailing lists and their use?
Read about mailing lists on Wikipedia
and check out these
guidelines on proper formatting of your messages.
