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[k-abe@cs: oskit/x86/proc_reg.h]
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Date: Thu, 21 Dec 2000 17:40:12 -0700
From: k-abe@cs
To: oskit@fast
Subject: oskit/x86/proc_reg.h
In oskit/x86/proc_reg.h, CR4_PGE is defined as 0x20.
I believe it should be 0x80.
(0x20 is `physical address extension' bit that enables 36bit physical
address space, should be defined as CR4_PAE).
However, no OSKit source uses this symbol.
/*
* CR4
*/
#define CR4_VME 0x00000001 /* enable virtual intrs in v86 mode */
#define CR4_PVI 0x00000002 /* enable virtual intrs in pmode */
#define CR4_TSD 0x00000004 /* disable RDTSC in user mode */
#define CR4_DE 0x00000008 /* debug extensions (I/O breakpoints) *
/
#define CR4_PSE 0x00000010 /* page size extensions */
#define CR4_PGE 0x00000020 /* page global extensions */
#define CR4_MCE 0x00000040 /* machine check exception */
#define CR4_PCE 0x00000100 /* enable read perf counter instr */
- --
Kota Abe
Dept. of Computer Science, Univ. of Utah.
Media Center, Osaka City Univ.
-----------
Date: Thu, 21 Dec 2000 23:51:18 -0500 (EST)
From: Roland McGrath <roland@frob.com>
To: k-abe@cs
Cc: oskit@fast
Subject: Re: oskit/x86/proc_reg.h
In-Reply-To: k-abe@cs.utah.edu's message of Thu, 21 December 2000 17:40:12 -0700 <814rzxp9ub.wl@localhost.cs.utah.edu>
> In oskit/x86/proc_reg.h, CR4_PGE is defined as 0x20.
> I believe it should be 0x80.
> (0x20 is `physical address extension' bit that enables 36bit physical
> address space, should be defined as CR4_PAE).
> However, no OSKit source uses this symbol.
Auuughghgh!! But I used it in oskit-mach, and several people spent some
time trying to figure out why it caused the kernel to crash. I read the
specs backwards and forewards trying to figure out what I was doing wrong,
and compared to the usage in BSD and Linux and gave up. It never occurred
to me that the constants might be wrong!
I put this into Fluke at one point too, though I don't recall anyone ever
seeing any problems with it. I do recall doing some benchmarks and
wondering why it never seemed to help as the manuals said it should.
------- End of Forwarded Messages