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[209.132.180.67]) by mx.google.com with ESMTP id a15si9568364eda.222.2019.10.01.07.25.04; Tue, 01 Oct 2019 07:25:04 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388959AbfJAOZD (ORCPT + 27 others); Tue, 1 Oct 2019 10:25:03 -0400 Received: from mout.kundenserver.de ([212.227.17.24]:47471 "EHLO mout.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727137AbfJAOZD (ORCPT ); Tue, 1 Oct 2019 10:25:03 -0400 Received: from threadripper.lan ([149.172.19.189]) by mrelayeu.kundenserver.de (mreue107 [212.227.15.145]) with ESMTPA (Nemesis) id 1MCsDe-1iO4WF0e6C-008vED; Tue, 01 Oct 2019 16:24:31 +0200 From: Arnd Bergmann To: Bill Metzenthen , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org Cc: Arnd Bergmann , "H. Peter Anvin" , Andrew Morton , Masahiro Yamada , linux-kernel@vger.kernel.org Subject: [PATCH 2/2] x86: math-emu: limit MATH_EMULATION to 486SX compatibles Date: Tue, 1 Oct 2019 16:23:35 +0200 Message-Id: <20191001142344.1274185-2-arnd@arndb.de> X-Mailer: git-send-email 2.20.0 In-Reply-To: <20191001142344.1274185-1-arnd@arndb.de> References: <20191001142344.1274185-1-arnd@arndb.de> MIME-Version: 1.0 X-Provags-ID: V03:K1:ypUbhs24V+XDzIu8RtxHkCDPsF9qgK2C2OcUaDTHYWX5qFZsDYX khdE+20BTsiQ/YldiJRPY7Uf5GP9VsST/YO0vGbYp5MC0yez+6jvokDzo3EenKPd/uyL0jf DI+LSXgleU8KGdPMSrsQ/D3qi0BKiiW829fkhIC7xVauaqgCmTC0QSaLtMT0VEyaEqaoB1e +03+Uwz6ejUUa7WfFA+GA== X-Spam-Flag: NO X-UI-Out-Filterresults: notjunk:1; V03:K0:ZU0EJxA0134=:mlj8N0pWTv4KLis9kqC4Xe 2s/A2zwEm3a8OJDTTB8qw1kV+7Qhd+AboSNmUNBKrkvLK3vjSI6fsOcGxShrOE07LnNa18cR4 fCETauDHyfkafu+tiRRywa+5COSa6nYNjIDzhOW3dJBdxv1vGCd3KADWujAU+gaqroKinBhHY zlDXYYeCc/nmLeHfSag0CWyhRkvaybsxYiIY5cKvprSud8HzVVrt+qMwJPP+VC8xm4AOE7OAP cCr/vpAUPUTp9Q3zAQpRADzBkiTIaU/WSVMJNR5W4zfUJQJKN6lAjUmmE7PMjRVeTGW9I+HgU F9Fwz9iUYecIe8QHOt0jcN7fGIyljlxhA0bnVZBFI8icBZIN6qi2ahNzTYs6M82nPXL1SoY7c 8IQP7ZZuf2Bbb84haJyVwyJbjTrRULj/04lehBsvMkuywvqUvlytS28lfkguIQECSvZ9DfFx4 zSXWEVHHnc4reh1x9B0WWiiASp8GluY5x55qdZpKXksDUX/wjCRIRBVWp+Kggehu6gCKo0ZFM E7w+AjLIrPmoVKcNLUiYvsGKCzF8aeAMDrnYnEx2Qz0t0Ho/mILXGMR4MWPpo+/afcgY/1ORI tEd9zgB59K06qhTuKa1HkWetEpko3QKyW+XaKCTj2mtIyD3L4wUKH9wmbECPk6a1b39h7A67B qhDScZX6TpeTtaXVucTlwT9tDGiDSiHokYSgH52ASwCmaRzF4sN/qTfNOtpeLfmzztiNVSqGy w8S/aTIjXu++MDuOyExUfVNyZkiXDyTCtPNdanPBy9SgtE5GX5pknUGr9RFE8UN9N9JpGRkYL vo3l6wbO2o1vVE44/gEQGwTvSoSFnJglUY18e/0W7Axs4bvI5J6ByvS4yuZCNy6AP4pVz/CMb ZVKAfBBilyme7ERrtTCg== Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The fpu emulation code is old and fragile in places, try to limit its use to builds for CPUs that actually use it. As far as I can tell, this is only true for i486sx compatibles, including the Cyrix 486SLC, AMD Am486SX and ÉLAN SC410, UMC U5S amd DM&P VortexSX86, all of which were relatively short-lived and got replaced with i486DX compatible processors soon after introduction, though the some of the embedded versions remained available much longer. Signed-off-by: Arnd Bergmann --- arch/x86/Kconfig | 2 +- arch/x86/Kconfig.cpu | 25 ++++++++++++++++--------- arch/x86/Makefile_32.cpu | 1 + arch/x86/include/asm/module.h | 2 ++ 4 files changed, 20 insertions(+), 10 deletions(-) -- 2.20.0 Reviewed-by: Kees Cook diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index f4d9d1e55e5c..77b02387bd0c 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1751,7 +1751,7 @@ config X86_RESERVE_LOW config MATH_EMULATION bool depends on MODIFY_LDT_SYSCALL - prompt "Math emulation" if X86_32 + prompt "Math emulation" if X86_32 && (M486SX || MELAN) ---help--- Linux can emulate a math coprocessor (used for floating point operations) if you don't have one. 486DX and Pentium processors have diff --git a/arch/x86/Kconfig.cpu b/arch/x86/Kconfig.cpu index 228705a1232a..5f7bff9885a1 100644 --- a/arch/x86/Kconfig.cpu +++ b/arch/x86/Kconfig.cpu @@ -50,12 +50,19 @@ choice See each option's help text for additional details. If you don't know what to do, choose "486". +config M486SX + bool "486SX" + depends on X86_32 + ---help--- + Select this for an 486-class CPU without an FPU such as + AMD/Cyrix/IBM/Intel SL/SLC/SLC2/SLC3/SX/SX2 and UMC U5S. + config M486 - bool "486" + bool "486DX" depends on X86_32 ---help--- Select this for an 486-class CPU such as AMD/Cyrix/IBM/Intel - 486DX/DX2/DX4 or SL/SLC/SLC2/SLC3/SX/SX2 and UMC U5D or U5S. + 486DX/DX2/DX4 and UMC U5D. config M586 bool "586/K5/5x86/6x86/6x86MX" @@ -313,20 +320,20 @@ config X86_L1_CACHE_SHIFT int default "7" if MPENTIUM4 || MPSC default "6" if MK7 || MK8 || MPENTIUMM || MCORE2 || MATOM || MVIAC7 || X86_GENERIC || GENERIC_CPU - default "4" if MELAN || M486 || MGEODEGX1 + default "4" if MELAN || M486SX || M486 || MGEODEGX1 default "5" if MWINCHIP3D || MWINCHIPC6 || MCRUSOE || MEFFICEON || MCYRIXIII || MK6 || MPENTIUMIII || MPENTIUMII || M686 || M586MMX || M586TSC || M586 || MVIAC3_2 || MGEODE_LX config X86_F00F_BUG def_bool y - depends on M586MMX || M586TSC || M586 || M486 + depends on M586MMX || M586TSC || M586 || M486SX || M486 config X86_INVD_BUG def_bool y - depends on M486 + depends on M486SX || M486 config X86_ALIGNMENT_16 def_bool y - depends on MWINCHIP3D || MWINCHIPC6 || MCYRIXIII || MELAN || MK6 || M586MMX || M586TSC || M586 || M486 || MVIAC3_2 || MGEODEGX1 + depends on MWINCHIP3D || MWINCHIPC6 || MCYRIXIII || MELAN || MK6 || M586MMX || M586TSC || M586 || M486SX || M486 || MVIAC3_2 || MGEODEGX1 config X86_INTEL_USERCOPY def_bool y @@ -379,7 +386,7 @@ config X86_MINIMUM_CPU_FAMILY config X86_DEBUGCTLMSR def_bool y - depends on !(MK6 || MWINCHIPC6 || MWINCHIP3D || MCYRIXIII || M586MMX || M586TSC || M586 || M486) && !UML + depends on !(MK6 || MWINCHIPC6 || MWINCHIP3D || MCYRIXIII || M586MMX || M586TSC || M586 || M486SX || M486) && !UML menuconfig PROCESSOR_SELECT bool "Supported processor vendors" if EXPERT @@ -403,7 +410,7 @@ config CPU_SUP_INTEL config CPU_SUP_CYRIX_32 default y bool "Support Cyrix processors" if PROCESSOR_SELECT - depends on M486 || M586 || M586TSC || M586MMX || (EXPERT && !64BIT) + depends on M486SX || M486 || M586 || M586TSC || M586MMX || (EXPERT && !64BIT) ---help--- This enables detection, tunings and quirks for Cyrix processors @@ -471,7 +478,7 @@ config CPU_SUP_TRANSMETA_32 config CPU_SUP_UMC_32 default y bool "Support UMC processors" if PROCESSOR_SELECT - depends on M486 || (EXPERT && !64BIT) + depends on M486SX || M486 || (EXPERT && !64BIT) ---help--- This enables detection, tunings and quirks for UMC processors diff --git a/arch/x86/Makefile_32.cpu b/arch/x86/Makefile_32.cpu index 1f5faf8606b4..cd3056759880 100644 --- a/arch/x86/Makefile_32.cpu +++ b/arch/x86/Makefile_32.cpu @@ -10,6 +10,7 @@ else tune = $(call cc-option,-mcpu=$(1),$(2)) endif +cflags-$(CONFIG_M486SX) += -march=i486 cflags-$(CONFIG_M486) += -march=i486 cflags-$(CONFIG_M586) += -march=i586 cflags-$(CONFIG_M586TSC) += -march=i586 diff --git a/arch/x86/include/asm/module.h b/arch/x86/include/asm/module.h index 7948a17febb4..c215d2762488 100644 --- a/arch/x86/include/asm/module.h +++ b/arch/x86/include/asm/module.h @@ -15,6 +15,8 @@ struct mod_arch_specific { #ifdef CONFIG_X86_64 /* X86_64 does not define MODULE_PROC_FAMILY */ +#elif defined CONFIG_M486SX +#define MODULE_PROC_FAMILY "486SX " #elif defined CONFIG_M486 #define MODULE_PROC_FAMILY "486 " #elif defined CONFIG_M586