From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754757AbbIBOiU (ORCPT ); Wed, 2 Sep 2015 10:38:20 -0400 Received: from mail-by2on0056.outbound.protection.outlook.com ([207.46.100.56]:17071 "EHLO na01-by2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1754009AbbIBOiS (ORCPT ); Wed, 2 Sep 2015 10:38:18 -0400 Authentication-Results: spf=none (sender IP is ) smtp.mailfrom=Yuri.Norov@caviumnetworks.com; Date: Wed, 2 Sep 2015 17:38:01 +0300 From: Yury Norov To: Ard Biesheuvel CC: Mark Rutland , "Suzuki K. Poulose" , Catalin Marinas , Alexey Klimov , , Will Deacon , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Subject: Re: [PATCH v2 2/2] arm64: don't load 32-bit binaries if platform has no aarch32_el0 Message-ID: <20150902143801.GA27761@yury-N73SV> References: <1441202438-27005-1-git-send-email-ynorov@caviumnetworks.com> <1441202438-27005-3-git-send-email-ynorov@caviumnetworks.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) X-Originating-IP: [91.77.150.194] X-ClientProxiedBy: HE1PR01CA0031.eurprd01.prod.exchangelabs.com (25.163.2.169) To CO2PR07MB619.namprd07.prod.outlook.com (10.141.228.151) X-Microsoft-Exchange-Diagnostics: 1;CO2PR07MB619;2:+8i1ZFwsIzdjJgTpgxHdeCIVpHGmLa1fK67+jjQkoPfBivcASYyJceRXjXPdXj9RCX3vkJfUbHE7ULgjnuou5H+bZMNdkLyZUVCmowGOdLX7oESbmyqW+c6D73hENSytK164sxnv0ImCUsezIM4ZMUJRmERhEVutTmN+Pi6Bp48=;3:0I+FcjzahMI7tgMYtK4lhfGVBJi4hiQ10lyuzIdNTqKv8fW4CBKLAbPJBwjyjuPii8lcgsF7h+/audKqH52ZfjfzlUy7Nly3QKc3LelYnh0AaqSg/BDdPR7Apx1oaGVG4nXvj2/szen9YU7l31mwDQ==;25:XsH2Xbd9YxTiS3rRZayEa10vemWnIab12SBxVWXpRTw4hwyu/2mUNSNy3Z8xilt+KsrF9BDN1wX8eAQdoB5ir+CKwQhSmBRSG5G9gnO3smDPnocWOzbky0bf9IhjfL9nDBBg7PJNV2rz7oanAjmSOs5bcmprKz5RlvVEysjuowG99DQD+UfEgrnOlTJ4zhTl6eRgX5Sndhj1s7Dh82IlmqUtD17a6znxZAeJ/u49FSkHLQrKQsQDLKhOSpc37Qazh5TlJhFE2QgoAVLx07KtwQ== X-Microsoft-Antispam: UriScan:;BCL:0;PCL:0;RULEID:;SRVR:CO2PR07MB619; 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But we cannot just disable COMPAT for them because the same > > kernel binary may be used by multiple platforms. > > > > In this patch, system_supports_aarch32_el0() is introduced to detect > > aarch32 support at run-time. > > > > Signed-off-by: Yury Norov > > --- > > arch/arm64/include/asm/cpufeature.h | 1 + > > arch/arm64/include/asm/cputype.h | 8 ++++++++ > > arch/arm64/include/asm/elf.h | 6 ++++-- > > arch/arm64/kernel/cpuinfo.c | 12 ++++++++++++ > > 4 files changed, 25 insertions(+), 2 deletions(-) > > > > diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h > > index f0e4017..35f2654 100644 > > --- a/arch/arm64/include/asm/cpufeature.h > > +++ b/arch/arm64/include/asm/cpufeature.h > > @@ -83,6 +83,7 @@ void check_local_cpu_errata(void); > > void check_local_cpu_features(void); > > bool cpu_supports_mixed_endian_el0(void); > > bool system_supports_mixed_endian_el0(void); > > +bool system_supports_aarch32_el0(void); > > > > #endif /* __ASSEMBLY__ */ > > > > diff --git a/arch/arm64/include/asm/cputype.h b/arch/arm64/include/asm/cputype.h > > index a84ec60..a24e42c 100644 > > --- a/arch/arm64/include/asm/cputype.h > > +++ b/arch/arm64/include/asm/cputype.h > > @@ -81,6 +81,9 @@ > > #define ID_AA64MMFR0_BIGEND(mmfr0) \ > > (((mmfr0) & ID_AA64MMFR0_BIGEND_MASK) >> ID_AA64MMFR0_BIGEND_SHIFT) > > > > +#define ID_AA64PFR0_EL0_64 1 > > +#define ID_AA64PFR0_EL0_6432 2 > > + > > #define SCTLR_EL1_CP15BEN (0x1 << 5) > > #define SCTLR_EL1_SED (0x1 << 8) > > > > @@ -116,6 +119,11 @@ static inline u32 __attribute_const__ read_cpuid_cachetype(void) > > return read_cpuid(CTR_EL0); > > } > > > > +static inline bool id_aa64pfr0_aarch32_el0(u64 pfr0) > > +{ > > + return pfr0 == ID_AA64PFR0_EL0_6432; > > +} > > + > > Shouldn't you be masking some bits in pfr0 before doing the comparison? > ID_AA64PFR0_EL1.EL0 occupies bits [3:0] only. > Yes, it was in v1 but I lost in v2. > > static inline bool id_aa64mmfr0_mixed_endian_el0(u64 mmfr0) > > { > > return (ID_AA64MMFR0_BIGEND(mmfr0) == 0x1) || > > diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h > > index faad6df..461897b 100644 > > --- a/arch/arm64/include/asm/elf.h > > +++ b/arch/arm64/include/asm/elf.h > > @@ -21,6 +21,7 @@ > > /* > > * ELF register definitions.. > > */ > > +#include > > #include > > #include > > > > @@ -173,8 +174,9 @@ typedef compat_elf_greg_t compat_elf_gregset_t[COMPAT_ELF_NGREG]; > > > > /* AArch32 EABI. */ > > #define EF_ARM_EABI_MASK 0xff000000 > > -#define compat_elf_check_arch(x) (((x)->e_machine == EM_ARM) && \ > > - ((x)->e_flags & EF_ARM_EABI_MASK)) > > +#define compat_elf_check_arch(x) (system_supports_aarch32_el0() \ > > + && ((x)->e_machine == EM_ARM) \ > > + && ((x)->e_flags & EF_ARM_EABI_MASK)) > > > > #define compat_start_thread compat_start_thread > > #define COMPAT_SET_PERSONALITY(ex) set_thread_flag(TIF_32BIT); > > diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c > > index 75d5a86..4a6ae31 100644 > > --- a/arch/arm64/kernel/cpuinfo.c > > +++ b/arch/arm64/kernel/cpuinfo.c > > @@ -36,6 +36,7 @@ > > DEFINE_PER_CPU(struct cpuinfo_arm64, cpu_data); > > static struct cpuinfo_arm64 boot_cpu_data; > > static bool mixed_endian_el0 = true; > > +static bool aarch32_el0 = true; > > > > static char *icache_policy_str[] = { > > [ICACHE_POLICY_RESERVED] = "RESERVED/UNKNOWN", > > @@ -79,13 +80,24 @@ bool system_supports_mixed_endian_el0(void) > > return mixed_endian_el0; > > } > > > > +bool system_supports_aarch32_el0(void) > > +{ > > + return aarch32_el0; > > +} > > + > > static void update_mixed_endian_el0_support(struct cpuinfo_arm64 *info) > > { > > mixed_endian_el0 &= id_aa64mmfr0_mixed_endian_el0(info->reg_id_aa64mmfr0); > > } > > > > +static void update_aarch32_el0_support(struct cpuinfo_arm64 *info) > > +{ > > + aarch32_el0 &= id_aa64pfr0_aarch32_el0(info->reg_id_aa64pfr0); > > +} > > + > > static void update_cpu_features(struct cpuinfo_arm64 *info) > > { > > + update_aarch32_el0_support(info); > > update_mixed_endian_el0_support(info); > > } > > > > -- > > 2.1.4 > >