From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E9C53C433E0 for ; Fri, 15 May 2020 17:17:24 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id A8A6420671 for ; Fri, 15 May 2020 17:17:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A8A6420671 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 59B478E001C; Fri, 15 May 2020 13:17:09 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 528BF8E0001; Fri, 15 May 2020 13:17:09 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 415038E001C; Fri, 15 May 2020 13:17:09 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0117.hostedemail.com [216.40.44.117]) by kanga.kvack.org (Postfix) with ESMTP id 286888E0001 for ; Fri, 15 May 2020 13:17:09 -0400 (EDT) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id E53DF6E097 for ; Fri, 15 May 2020 17:17:08 +0000 (UTC) X-FDA: 76819608936.20.horse64_425809f6c952 X-HE-Tag: horse64_425809f6c952 X-Filterd-Recvd-Size: 8327 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf45.hostedemail.com (Postfix) with ESMTP for ; Fri, 15 May 2020 17:17:08 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id DAD4B11D4; Fri, 15 May 2020 10:17:07 -0700 (PDT) Received: from localhost.localdomain (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 03E223F305; Fri, 15 May 2020 10:17:05 -0700 (PDT) From: Catalin Marinas To: linux-arm-kernel@lists.infradead.org Cc: linux-mm@kvack.org, linux-arch@vger.kernel.org, Will Deacon , Dave P Martin , Vincenzo Frascino , Szabolcs Nagy , Kevin Brodsky , Andrey Konovalov , Peter Collingbourne , Rob Herring , Mark Rutland Subject: [PATCH v4 23/26] arm64: mte: Check the DT memory nodes for MTE support Date: Fri, 15 May 2020 18:16:09 +0100 Message-Id: <20200515171612.1020-24-catalin.marinas@arm.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200515171612.1020-1-catalin.marinas@arm.com> References: <20200515171612.1020-1-catalin.marinas@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Even if the ID_AA64PFR1_EL1 register advertises the presence of MTE, it is not guaranteed that the memory system on the SoC supports the feature. In the absence of system-wide MTE support, the behaviour is undefined and the kernel should not enable the MTE memory type in MAIR_EL1. For FDT, add an 'arm,armv8.5-memtag' property to the /memory nodes and check for its presence during MTE probing. For example: memory@80000000 { device_type =3D "memory"; arm,armv8.5-memtag; reg =3D <0x00000000 0x80000000 0 0x80000000>, <0x00000008 0x80000000 0 0x80000000>; }; If the /memory nodes are not present in DT or if at least one node does not support MTE, the feature will be disabled. On EFI systems, it is assumed that the memory description matches the EFI memory map (if not, it is considered a firmware bug). MTE is not currently supported on ACPI systems. Signed-off-by: Catalin Marinas Cc: Rob Herring Cc: Mark Rutland Cc: Will Deacon Reviewed-by: Suzuki K Poulose --- Notes: Ongoing (internal) discussions on whether this is the right approach. The issue may need to be solved similarly for ACPI systems. =20 v4: - Reworked the CPUID field handling to ensure that it is not exposed = to user (via MRS emulation) when the feature is not described in the D= T. Previously, only the HWCAP was hidden. =20 New in v3. arch/arm64/boot/dts/arm/fvp-base-revc.dts | 1 + arch/arm64/include/asm/cpufeature.h | 6 ++- arch/arm64/kernel/cpufeature.c | 59 ++++++++++++++++++++--- 3 files changed, 58 insertions(+), 8 deletions(-) diff --git a/arch/arm64/boot/dts/arm/fvp-base-revc.dts b/arch/arm64/boot/= dts/arm/fvp-base-revc.dts index 66381d89c1ce..c620a289f15e 100644 --- a/arch/arm64/boot/dts/arm/fvp-base-revc.dts +++ b/arch/arm64/boot/dts/arm/fvp-base-revc.dts @@ -94,6 +94,7 @@ =20 memory@80000000 { device_type =3D "memory"; + arm,armv8.5-memtag; reg =3D <0x00000000 0x80000000 0 0x80000000>, <0x00000008 0x80000000 0 0x80000000>; }; diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm= /cpufeature.h index afc315814563..0a24d36bf231 100644 --- a/arch/arm64/include/asm/cpufeature.h +++ b/arch/arm64/include/asm/cpufeature.h @@ -61,6 +61,7 @@ struct arm64_ftr_bits { u8 shift; u8 width; s64 safe_val; /* safe value for FTR_EXACT features */ + s64 (*filter)(const struct arm64_ftr_bits *, s64); }; =20 /* @@ -542,7 +543,10 @@ cpuid_feature_extract_field(u64 features, int field,= bool sign) =20 static inline s64 arm64_ftr_value(const struct arm64_ftr_bits *ftrp, u64= val) { - return (s64)cpuid_feature_extract_field_width(val, ftrp->shift, ftrp->w= idth, ftrp->sign); + s64 fval =3D (s64)cpuid_feature_extract_field_width(val, ftrp->shift, f= trp->width, ftrp->sign); + if (ftrp->filter) + fval =3D ftrp->filter(ftrp, fval); + return fval; } =20 static inline bool id_aa64mmfr0_mixed_endian_el0(u64 mmfr0) diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeatur= e.c index d2fe8ff72324..aaadc1cbc006 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -7,6 +7,7 @@ =20 #define pr_fmt(fmt) "CPU features: " fmt =20 +#include #include #include #include @@ -14,6 +15,7 @@ #include #include #include +#include #include #include #include @@ -87,23 +89,28 @@ DEFINE_STATIC_KEY_ARRAY_FALSE(cpu_hwcap_keys, ARM64_N= CAPS); EXPORT_SYMBOL(cpu_hwcap_keys); =20 #define __ARM64_FTR_BITS(SIGNED, VISIBLE, STRICT, TYPE, SHIFT, WIDTH, SA= FE_VAL) \ - { \ .sign =3D SIGNED, \ .visible =3D VISIBLE, \ .strict =3D STRICT, \ .type =3D TYPE, \ .shift =3D SHIFT, \ .width =3D WIDTH, \ - .safe_val =3D SAFE_VAL, \ - } + .safe_val =3D SAFE_VAL =20 /* Define a feature with unsigned values */ #define ARM64_FTR_BITS(VISIBLE, STRICT, TYPE, SHIFT, WIDTH, SAFE_VAL) \ - __ARM64_FTR_BITS(FTR_UNSIGNED, VISIBLE, STRICT, TYPE, SHIFT, WIDTH, SAF= E_VAL) + { __ARM64_FTR_BITS(FTR_UNSIGNED, VISIBLE, STRICT, TYPE, SHIFT, WIDTH, S= AFE_VAL), } =20 /* Define a feature with a signed value */ #define S_ARM64_FTR_BITS(VISIBLE, STRICT, TYPE, SHIFT, WIDTH, SAFE_VAL) = \ - __ARM64_FTR_BITS(FTR_SIGNED, VISIBLE, STRICT, TYPE, SHIFT, WIDTH, SAFE_= VAL) + { __ARM64_FTR_BITS(FTR_SIGNED, VISIBLE, STRICT, TYPE, SHIFT, WIDTH, SAF= E_VAL), } + +/* Define a feature with a filter function to process the field value */ +#define FILTERED_ARM64_FTR_BITS(SIGNED, VISIBLE, STRICT, TYPE, SHIFT, WI= DTH, SAFE_VAL, filter_fn) \ + { \ + __ARM64_FTR_BITS(SIGNED, VISIBLE, STRICT, TYPE, SHIFT, WIDTH, SAFE_VAL= ), \ + .filter =3D filter_fn, \ + } =20 #define ARM64_FTR_END \ { \ @@ -118,6 +125,42 @@ static void cpu_enable_cnp(struct arm64_cpu_capabili= ties const *cap); =20 static bool __system_matches_cap(unsigned int n); =20 +#ifdef CONFIG_ARM64_MTE +s64 mte_ftr_filter(const struct arm64_ftr_bits *ftrp, s64 val) +{ + struct device_node *np; + static bool memory_checked =3D false; + static bool mte_capable =3D true; + + /* EL0-only MTE is not supported by Linux, don't expose it */ + if (val < ID_AA64PFR1_MTE) + return ID_AA64PFR1_MTE_NI; + + if (memory_checked) + return mte_capable ? val : ID_AA64PFR1_MTE_NI; + + if (!acpi_disabled) { + pr_warn("MTE not supported on ACPI systems\n"); + return ID_AA64PFR1_MTE_NI; + } + + /* check the DT "memory" nodes for MTE support */ + for_each_node_by_type(np, "memory") { + memory_checked =3D true; + mte_capable &=3D of_property_read_bool(np, "arm,armv8.5-memtag"); + } + + if (!memory_checked || !mte_capable) { + pr_warn("System memory is not MTE-capable\n"); + memory_checked =3D true; + mte_capable =3D false; + return ID_AA64PFR1_MTE_NI; + } + + return val; +} +#endif + /* * NOTE: Any changes to the visibility of features should be kept in * sync with the documentation of the CPU feature register ABI. @@ -182,8 +225,10 @@ static const struct arm64_ftr_bits ftr_id_aa64pfr0[]= =3D { =20 static const struct arm64_ftr_bits ftr_id_aa64pfr1[] =3D { ARM64_FTR_BITS(FTR_VISIBLE, FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR1_SSB= S_SHIFT, 4, ID_AA64PFR1_SSBS_PSTATE_NI), - ARM64_FTR_BITS(FTR_VISIBLE_IF_IS_ENABLED(CONFIG_ARM64_MTE), - FTR_STRICT, FTR_LOWER_SAFE, ID_AA64PFR1_MTE_SHIFT, 4, ID_AA64PF= R1_MTE_NI), +#ifdef CONFIG_ARM64_MTE + FILTERED_ARM64_FTR_BITS(FTR_UNSIGNED, FTR_VISIBLE, FTR_STRICT, FTR_LOWE= R_SAFE, + ID_AA64PFR1_MTE_SHIFT, 4, ID_AA64PFR1_MTE_NI, mte_ftr_filter), +#endif ARM64_FTR_END, }; =20