Bug 12071
Summary: | nx not enabled with 32/64bit PAE when forced off in BIOS | ||
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Product: | Platform Specific/Hardware | Reporter: | Kees Cook (kees) |
Component: | i386 | Assignee: | platform_i386 |
Status: | REJECTED INVALID | ||
Severity: | enhancement | ||
Priority: | P1 | ||
Hardware: | All | ||
OS: | Linux | ||
Kernel Version: | 2.6.27 | Subsystem: | |
Regression: | --- | Bisected commit-id: | |
Attachments: | NX test case |
Description
Kees Cook
2008-11-20 15:47:11 UTC
Created attachment 18959 [details]
NX test case
Also noted that on the T5750, "nx" only shows up on CPU1: $ grep flags /proc/cpuinfo flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe lm constant_tsc arch_perfmon pebs bts pni monitor ds_cpl est tm2 ssse3 cx16 xtpr lahf_lm flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc arch_perfmon pebs bts pni monitor ds_cpl est tm2 ssse3 cx16 xtpr lahf_lm (re: Regression tag, it is possible this has never worked for whatever CPUs are seeing this issue.) Ah-ha, thanks to a hint from Arjan, it seems this is a BIOS override. On another Dell I was able to disable nx by turning of the "CPU XD Support" under "Security". Is there some way to work around this, perhaps? Linux honours the BIOS. That is what was clearly desired by users. |