From 87d6021b814353d7b353afcc3698ffe49de7d4ec Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Tue, 1 Oct 2019 16:23:35 +0200 Subject: x86/math-emu: Limit MATH_EMULATION to 486SX compatibles MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 some of the embedded versions remained available much longer. Signed-off-by: Arnd Bergmann Signed-off-by: Borislav Petkov Reviewed-by: Kees Cook Cc: "H. Peter Anvin" Cc: Andrew Morton Cc: Bill Metzenthen Cc: Ingo Molnar Cc: Masahiro Yamada Cc: Thomas Gleixner Cc: x86-ml Link: https://lkml.kernel.org/r/20191001142344.1274185-2-arnd@arndb.de --- arch/x86/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'arch/x86/Kconfig') diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index d6e1faa28c58..91c22ee6bc9a 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 -- cgit v1.2.3