From patchwork Fri Feb 25 15:04:12 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Peter Maydell X-Patchwork-Id: 215 Return-Path: Delivered-To: unknown Received: from imap.gmail.com (74.125.159.109) by localhost6.localdomain6 with IMAP4-SSL; 08 Jun 2011 14:40:57 -0000 Delivered-To: patches@linaro.org Received: by 10.224.19.208 with SMTP id c16cs11826qab; Fri, 25 Feb 2011 07:06:19 -0800 (PST) Received: by 10.216.81.69 with SMTP id l47mr2161077wee.56.1298646257420; Fri, 25 Feb 2011 07:04:17 -0800 (PST) Received: from mnementh.archaic.org.uk (mnementh.archaic.org.uk [81.2.115.146]) by mx.google.com with ESMTPS id o56si1443999weq.58.2011.02.25.07.04.16 (version=TLSv1/SSLv3 cipher=OTHER); Fri, 25 Feb 2011 07:04:17 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of pm215@archaic.org.uk designates 81.2.115.146 as permitted sender) client-ip=81.2.115.146; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of pm215@archaic.org.uk designates 81.2.115.146 as permitted sender) smtp.mail=pm215@archaic.org.uk Received: from pm215 by mnementh.archaic.org.uk with local (Exim 4.72) (envelope-from ) id 1PszDI-0006IG-Tf; Fri, 25 Feb 2011 15:04:12 +0000 From: Peter Maydell To: qemu-devel@nongnu.org Cc: Adam Lackorzynski , patches@linaro.org Subject: [PATCH] target-arm: Don't decode old cp15 WFI instructions on v7 cores Date: Fri, 25 Feb 2011 15:04:12 +0000 Message-Id: <1298646252-24169-1-git-send-email-peter.maydell@linaro.org> X-Mailer: git-send-email 1.7.2.3 In v7 of the ARM architecture, WFI (wait for interrupt) is a first-class instruction, but in previous versions this functionality was provided via a cp15 coprocessor register. Add correct feature checks to the decoding of the cp15 WFI instructions so that they behave correctly for newer cores. In particular, the old 0,c7,c8,2 encoding used on ARM940 has been reused for VA-to-PA translation in v6 and v7. Signed-off-by: Peter Maydell Reviewed-by: Adam Lackorzynski --- This patch stands alone as a fix to target-arm; it's a prerequisite for Adam's VA->PA translation patch, because otherwise attempting a user-read translation will get you a WFI instead... target-arm/translate.c | 35 ++++++++++++++++++++++++++++++----- 1 files changed, 30 insertions(+), 5 deletions(-) diff --git a/target-arm/translate.c b/target-arm/translate.c index dbd958b..baa1256 100644 --- a/target-arm/translate.c +++ b/target-arm/translate.c @@ -2538,13 +2538,38 @@ static int disas_cp15_insn(CPUState *env, DisasContext *s, uint32_t insn) if (IS_USER(s) && !cp15_user_ok(insn)) { return 1; } - if ((insn & 0x0fff0fff) == 0x0e070f90 - || (insn & 0x0fff0fff) == 0x0e070f58) { - /* Wait for interrupt. */ - gen_set_pc_im(s->pc); - s->is_jmp = DISAS_WFI; + + /* Pre-v7 versions of the architecture implemented WFI via coprocessor + * instructions rather than a separate instruction. + */ + if ((insn & 0x0fff0fff) == 0x0e070f90) { + /* 0,c7,c0,4: Standard v6 WFI (also used in some pre-v6 cores). + * In v7, this must NOP. + */ + if (!arm_feature(env, ARM_FEATURE_V7)) { + /* Wait for interrupt. */ + gen_set_pc_im(s->pc); + s->is_jmp = DISAS_WFI; + } return 0; } + + if ((insn & 0x0fff0fff) == 0x0e070f58) { + /* 0,c7,c8,2: Not all pre-v6 cores implemented this WFI, + * so this is slightly over-broad. + */ + if (!arm_feature(env, ARM_FEATURE_V6)) { + /* Wait for interrupt. */ + gen_set_pc_im(s->pc); + s->is_jmp = DISAS_WFI; + return 0; + } + /* Otherwise fall through to handle via helper function. + * In particular, on v7 and some v6 cores this is one of + * the VA-PA registers. + */ + } + rd = (insn >> 12) & 0xf; if (cp15_tls_load_store(env, s, insn, rd))