| 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
| ||
|
Message-ID: <55B6011C.9070906@codethink.co.uk> Date: Mon, 27 Jul 2015 10:59:56 +0100 From: Ben Dooks <ben.dooks@...ethink.co.uk> To: Sebastian Reichel <sre@...nel.org>, Russell King - ARM Linux <linux@....linux.org.uk> CC: Tony Lindgren <tony@...mide.com>, linux-omap@...r.kernel.org, linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org Subject: Re: [PATCH 3/3] ARM: errata 430973: move !ARCH_MULTIPLATFORM to Kconfig On 27/07/15 02:14, Sebastian Reichel wrote: > Hi, > > On Sun, Jul 26, 2015 at 11:51:45PM +0100, Russell King - ARM Linux > wrote: >> On Fri, Jul 24, 2015 at 02:16:06AM +0200, Sebastian Reichel >> wrote: >>> On Thu, Jul 23, 2015 at 01:35:53PM +0100, Russell King - ARM >>> Linux wrote: >>>> On Thu, Jul 23, 2015 at 02:48:03AM +0200, Sebastian Reichel >>>> wrote: >>>>> Having the !ARCH_MULTIPLATFORM dependency in the Kconfig >>>>> file results in one option less to think about when >>>>> configuring the kernel. >>>> >>>>> -#if defined(CONFIG_ARM_ERRATA_430973) && >>>>> !defined(CONFIG_ARCH_MULTIPLATFORM) +#ifdef >>>>> CONFIG_ARM_ERRATA_430973 teq r3, #0x00100000 @ only >>>>> present in r1p* mrceq p15, 0, r0, c1, c0, 1 @ read aux >>>>> control register orreq r0, r0, #(1 << 6) @ set IBE to 1 >>>> >>>> NAK. Please read the mailing list history, I'm not >>>> repeating myself again on this. Thanks. >>> >>> It's a bit hard to search the mailing list history without a >>> bit more information. >> >> You were Cc'd on the previous round of review... > > But that discussion was about removing the check alltogether iirc. > This patch does not remove the !ARCH_MULTIPLATFORM check. It just > *moves* it from the sourcecode to the errata's Kconfig entry. > > The intention was to hide the Kconfig option on multiplatform > kernels, since it's completely useless there after the N900 > boardcode has been changed (PATCH 1/3). > >>> I guess you prefer to just add the !ARCH_MULTIPLATFORM >>> dependency to the Kconfig entry without removing the >>> additional check in the code? >> >> I was referring to the above change. >> >> However, having discussed with Will Deacon and checked the >> manuals, I think the change is okay after all: the auxillary >> control register is banked on secure parts, and the bit we'll be >> trying to change will be read-only in non-secure mode - and >> importantly won't fault. >> >> So, the change is fine, thanks. > > I think you missed the part adding the !ARCH_MULTIPLATFORM > dependency in Kconfig for ARM_ERRATA_430973. I only removed the > check in the sourcecode, since it is no longer required with the > dependency being in Kconfig. > > So I guess there are 3 options now: > > 1. Add !ARCH_MULTIPLATFORM dependency to Kconfig, keep extra check > in the sourcecode 2. Add !ARCH_MULTIPLATFORM dependency to Kconfig, > remove extra check in the sourcecode 3. Remove !ARCH_MULTIPLATFORM > dependency alltogether > > I will send an appropriate patch, if you tell me your preferred > option. This isn't the only place ARM_ERRATA_430973 is used, and if you make it configurable on !ARCH_MULTIPLATFORM then it makes it impossible to use a ARCH_MULTIPLATFORM kernel on something that is an Cortex-A8. See arch/arm/mm/proc-v7-2level.S -- Ben Dooks http://www.codethink.co.uk/ Senior Engineer Codethink - Providing Genius -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists