Date: Tue, 18 Nov 1997 21:14:02 +0900 From: KATO Takenori <kato@migmatite.eps.nagoya-u.ac.jp> To: hometeam@techpower.net Cc: freebsd-security@FreeBSD.ORG Subject: Re: now a Cyrix processor bug Message-ID: <199711181214.VAA06906@gneiss.eps.nagoya-u.ac.jp> In-Reply-To: Your message of "Tue, 18 Nov 1997 06:39:21 %2B0000 (GMT)" References: <Pine.BSF.3.96.971118063630.9708A-100000@techpower.net>
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> CPU_CYRIX_NO_LOCK This is a kernel configuration option. Cyrix options in FreeBSD are described in /sys/i386/conf/LINT. (from LINT) # CPU_BTB_EN enables branch target buffer on Cyrix 5x86 (NOTE 1). # # CPU_DIRECT_MAPPED_CACHE set L1 cache of Cyrix 486DLC CPU in direct # mapped mode. Default is 2-way set associative mode. # # CPU_CYRIX_NO_LOCK enables weak locking for the entire address space # of Cyrix 6x86 and 6x86MX CPUs. If this option is not set and # FAILESAFE is defined, NO_LOCK bit of CCR1 is cleared. (NOTE 3) # # CPU_DISABLE_5X86_LSSER disables load store serialize (i.e. enables # reorder). This option should not be used if you use memory mapped # I/O device(s). # # CPU_FASTER_5X86_FPU enables faster FPU exception handler. # # CPU_IORT defines I/O clock delay time (NOTE 1). Default vaules of # I/O clock delay time on Cyrix 5x86 and 6x86 are 0 and 7,respectively # (no clock delay). # # CPU_LOOP_EN prevents flushing the prefetch buffer if the destination # of a jump is already present in the prefetch buffer on Cyrix 5x86(NOTE # 1). # # CPU_RSTK_EN enables return stack on Cyrix 5x86 (NOTE 1). # # CPU_SUSP_HLT enables suspend on HALT. If this option is set, CPU # enters suspend mode following execution of HALT instruction. # # CPU_WT_ALLOC enables write-through allocation. # # CYRIX_CACHE_WORKS enables CPU cache on Cyrix 486 CPUs with cache # flush at hold state. # # CYRIX_CACHE_REALLY_WORKS enables (1) CPU cache on Cyrix 486 CPUs # without cache flush at hold state, and (2) write-back CPU cache on # Cyrix 6x86 whose revision < 2.7 (NOTE 2). # # NOTE 1: The options, CPU_BTB_EN, CPU_LOOP_EN, CPU_IORT, # CPU_LOOP_EN and CPU_RSTK_EN should no be used becasue of CPU bugs. # These options may crash your system. # # NOTE 2: If CYRIX_CACHE_REALLY_WORKS is not set, CPU cache is enabled # in write-through mode when revision < 2.7. If revision of Cyrix # 6x86 >= 2.7, CPU cache is always enabled in write-back mode. # # NOTE 3: This option may cause failures for software that requires # locked cycles in order to operate correctly. ---- KATO Takenori <kato@ganko.eps.nagoya-u.ac.jp> Dept. Earth Planet. Sci., Nagoya Univ., Nagoya, 464-01, Japan PGP public key: finger kato@eclogite.eps.nagoya-u.ac.jp ------------------- Powered by FreeBSD(98) -------------------
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