* Why ?
@ 2000-03-27 8:06 pnilesh
2000-03-27 10:46 ` Stephen C. Tweedie
2000-03-27 16:59 ` Benjamin C.R. LaHaise
0 siblings, 2 replies; 3+ messages in thread
From: pnilesh @ 2000-03-27 8:06 UTC (permalink / raw)
To: linux-mm
Why the first 0x0 - 0x07ffffff virtual addresses are not used by any
process ?
Is that used by the kernel and if yes for what ?
Nilesh Patel
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* Re: Why ?
2000-03-27 8:06 Why ? pnilesh
@ 2000-03-27 10:46 ` Stephen C. Tweedie
2000-03-27 16:59 ` Benjamin C.R. LaHaise
1 sibling, 0 replies; 3+ messages in thread
From: Stephen C. Tweedie @ 2000-03-27 10:46 UTC (permalink / raw)
To: pnilesh; +Cc: linux-mm, Stephen Tweedie
Hi,
On Mon, Mar 27, 2000 at 01:36:19PM +0530, pnilesh@in.ibm.com wrote:
> Why the first 0x0 - 0x07ffffff virtual addresses are not used by any
> process ?
> Is that used by the kernel and if yes for what ?
No, the entire 3GB user virtual address space is usable by user space.
It's the compiler/linker toolset which requests that ELF binaries be
loaded at 0x08000000. As for a reason, the only one I'm aware of is
that that's what the ELF standard says. :-) It does offer a solid
protection against dereferencing uninitialised pointers, though.
--Stephen
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* Re: Why ?
2000-03-27 8:06 Why ? pnilesh
2000-03-27 10:46 ` Stephen C. Tweedie
@ 2000-03-27 16:59 ` Benjamin C.R. LaHaise
1 sibling, 0 replies; 3+ messages in thread
From: Benjamin C.R. LaHaise @ 2000-03-27 16:59 UTC (permalink / raw)
To: pnilesh; +Cc: linux-mm
On Mon, 27 Mar 2000 pnilesh@in.ibm.com wrote:
> Why the first 0x0 - 0x07ffffff virtual addresses are not used by any
> process ?
I think it's to help catch NULL pointer dereferences.
> Is that used by the kernel and if yes for what ?
Other than the aforementioned reason, no.
-ben
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