Linux version 2.6.24.1 (dave@yellowbeard) (gcc version 4.2.1) #3 Sat Feb 9 22:24:04 EST 2008 Running on a 166 MHz Pentium "Classic." Console messages during boot correctly note the presence of the F00F bug: Intel Pentium with F0 0F bug - workaround enabled. However, /proc/cpuinfo does not (and 0 cache is wrong too): processor : 0 vendor_id : GenuineIntel cpu family : 5 model : 2 model name : Pentium 75 - 200 stepping : 12 cpu MHz : 165.794 cache size : 0 KB fdiv_bug : no hlt_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 1 wp : yes flags : fpu vme de pse tsc msr mce cx8 bogomips : 332.94 clflush size : 32 Other possibly helpful info from dmesg: CPU: After generic identify, caps: 000001bf 00000000 00000000 00000000 00000000 00000000 00000000 00000000 CPU: After all inits, caps: 000001bf 00000000 00000000 00000000 00000000 0000000 0 00000000 00000000
Is this fixed in current mainline ?
Doubt it. Pentium Classic didn't export information about the cache size, so it's likely to be unavailable unless we compile in a table. I don't know if the F00F message is right or not. We always activate the workaround (readonly GDT, I believe) if we see a Pentium Classic.
Created attachment 17643 [details] CPU info according to Intel Processor Frequency ID Utility Linux version 2.6.26.3-CD (root@yellowbeard) (gcc version 4.3.2 (GCC) ) #2 SMP Mon Sep 1 16:32:31 EDT 2008 The only change was the addition of "up" to the flags line of cpuinfo. Intel doesn't detect the L2 cache either (see attachment). For this chipset the L2 cache is a separate module that comes in various sizes independent of the CPU. init_intel in arch/x86/kernel/cpu/intel.c sets c->f00f_bug = 1. So what happens to that cpuinfo_x86 afterward?
There is a memory overwrite bug that is fixed in one of the 2.6.27-rcX kernels. Please try the latest -rc kernel to verify.
Yeah, that did it. Linux version 2.6.27-rc5-quake (root@yellowbeard) (gcc version 4.3.2 (GCC) ) #1 SMP Fri Sep 5 21:59:10 EDT 2008 processor : 0 vendor_id : GenuineIntel cpu family : 5 model : 2 model name : Pentium 75 - 200 stepping : 12 cpu MHz : 165.794 cache size : 0 KB fdiv_bug : no hlt_bug : no f00f_bug : yes coma_bug : no fpu : yes fpu_exception : yes cpuid level : 1 wp : yes flags : fpu vme de pse tsc msr mce cx8 up bogomips : 331.40 clflush size : 32 power management: