From patchwork Wed Aug 10 10:13:43 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dave Martin X-Patchwork-Id: 3344 Return-Path: X-Original-To: patchwork@peony.canonical.com Delivered-To: patchwork@peony.canonical.com Received: from fiordland.canonical.com (fiordland.canonical.com [91.189.94.145]) by peony.canonical.com (Postfix) with ESMTP id D616123F46 for ; Wed, 10 Aug 2011 10:14:02 +0000 (UTC) Received: from mail-qy0-f173.google.com (mail-qy0-f173.google.com [209.85.216.173]) by fiordland.canonical.com (Postfix) with ESMTP id A4FC3A18835 for ; Wed, 10 Aug 2011 10:14:02 +0000 (UTC) Received: by mail-qy0-f173.google.com with SMTP id 31so3151111qyk.11 for ; Wed, 10 Aug 2011 03:14:02 -0700 (PDT) Received: by 10.229.44.195 with SMTP id b3mr6305175qcf.7.1312971242404; Wed, 10 Aug 2011 03:14:02 -0700 (PDT) X-Forwarded-To: linaro-patchwork@canonical.com X-Forwarded-For: patch@linaro.org linaro-patchwork@canonical.com Delivered-To: patches@linaro.org Received: by 10.229.190.71 with SMTP id dh7cs74596qcb; Wed, 10 Aug 2011 03:14:02 -0700 (PDT) Received: from mr.google.com ([10.216.255.18]) by 10.216.255.18 with SMTP id i18mr9005897wes.64.1312971242093 (num_hops = 1); Wed, 10 Aug 2011 03:14:02 -0700 (PDT) Received: by 10.216.255.18 with SMTP id i18mr6313152wes.64.1312971241597; Wed, 10 Aug 2011 03:14:01 -0700 (PDT) Received: from mail-ww0-f50.google.com (mail-ww0-f50.google.com [74.125.82.50]) by mx.google.com with ESMTPS id y18si1980236weq.137.2011.08.10.03.14.00 (version=TLSv1/SSLv3 cipher=OTHER); Wed, 10 Aug 2011 03:14:01 -0700 (PDT) Received-SPF: neutral (google.com: 74.125.82.50 is neither permitted nor denied by best guess record for domain of dave.martin@linaro.org) client-ip=74.125.82.50; Authentication-Results: mx.google.com; spf=neutral (google.com: 74.125.82.50 is neither permitted nor denied by best guess record for domain of dave.martin@linaro.org) smtp.mail=dave.martin@linaro.org Received: by mail-ww0-f50.google.com with SMTP id 36so955547wwi.31 for ; Wed, 10 Aug 2011 03:14:00 -0700 (PDT) Received: by 10.227.13.77 with SMTP id b13mr6764327wba.54.1312971240832; Wed, 10 Aug 2011 03:14:00 -0700 (PDT) Received: from e200948.peterhouse.linaro.org (fw-lnat.cambridge.arm.com [217.140.96.63]) by mx.google.com with ESMTPS id fr7sm627419wbb.22.2011.08.10.03.13.59 (version=SSLv3 cipher=OTHER); Wed, 10 Aug 2011 03:14:00 -0700 (PDT) From: Dave Martin To: linux-arm-kernel@lists.infradead.org Cc: patches@linaro.org, Ben Dooks , Kukjin Kim , Nicolas Pitre , Jon Medhurst Subject: [RFC PATCH 5/5] ARM: entry: Fix Thumb-2 undef handling for multi-CPU kernels Date: Wed, 10 Aug 2011 11:13:43 +0100 Message-Id: <1312971223-28165-6-git-send-email-dave.martin@linaro.org> X-Mailer: git-send-email 1.7.4.1 In-Reply-To: <1312971223-28165-1-git-send-email-dave.martin@linaro.org> References: <1312971223-28165-1-git-send-email-dave.martin@linaro.org> When v6 and >=v7 boards are supported in the same kernel, the __und_usr code currently makes a build-time assumption that Thumb-2 instructions occurring in userspace don't need to be supported. Strictly speaking this is incorrect. This patch fixes the above case by doing a run-time check on the CPU architecture in these cases. This only affects kernels which support v6 and >=v7 CPUs together: plain v6 and plain v7 kernels are unaffected. Signed-off-by: Dave Martin --- arch/arm/kernel/entry-armv.S | 38 +++++++++++++++++++++++++++++++++++++- 1 files changed, 37 insertions(+), 1 deletions(-) diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S index b7236d4..bc41ebd 100644 --- a/arch/arm/kernel/entry-armv.S +++ b/arch/arm/kernel/entry-armv.S @@ -24,6 +24,7 @@ #include #include #include +#include #include "entry-header.S" #include @@ -439,7 +440,27 @@ __und_usr: #endif beq call_fpe @ Thumb instruction -#if __LINUX_ARM_ARCH__ >= 7 +#if CONFIG_ARM_THUMB && __LINUX_ARM_ARCH__ >= 6 && CONFIG_CPU_V7 +/* + * Thumb-2 instruction handling. Note that because pre-v6 and >= v6 platforms + * can never be supported in a single kernel, this code is not applicable at + * all when __LINUX_ARM_ARCH__ < 6. This allows simplifying assumptions to be + * made about .arch directives. + */ +#if __LINUX_ARM_ARCH__ < 7 +/* If the target CPU may not be Thumb-2-capable, a run-time check is needed: */ +#define NEED_CPU_ARCHITECTURE + ldr r5, .LCcpu_architecture + ldr r5, [r5] + cmp r5, #CPU_ARCH_ARMv7 + blo __und_usr_unknown +/* + * The following code won't get run unless the running CPU really is v7, so + * coding round the lack of ldrht on older arches is pointless. Temporarily + * override the assembler target arch with the minimum required instead: + */ + .arch armv6t2 +#endif 2: ARM( ldrht r5, [r4], #2 ) THUMB( ldrht r5, [r4] ) @@ -449,7 +470,16 @@ __und_usr: 3: ldrht r0, [r4] add r2, r2, #2 @ r2 is PC + 2, make it PC + 4 orr r0, r0, r5, lsl #16 + +#if __LINUX_ARM_ARCH__ < 7 +/* If the target arch was overridden, change it back: */ +#ifdef CONFIG_CPU_32v6K + .arch armv6k #else + .arch armv6 +#endif +#endif /* __LINUX_ARM_ARCH__ < 7 */ +#else /* !(CONFIG_ARM_THUMB && __LINUX_ARM_ARCH__ >= 6 && CONFIG_CPU_V7) */ b __und_usr_unknown #endif UNWIND(.fnend ) @@ -576,6 +606,12 @@ call_fpe: movw_pc lr @ CP#14 (Debug) movw_pc lr @ CP#15 (Control) +#ifdef NEED_CPU_ARCHITECTURE + .align 2 +.LCcpu_architecture: + .word cpu_architecture +#endif + #ifdef CONFIG_NEON .align 6