* [PATCH] Dead code in i386/kernel/process.c
@ 2002-08-03 22:39 Brian Gerst
2002-08-03 23:09 ` Brian Gerst
2002-08-04 15:45 ` Jamie Lokier
0 siblings, 2 replies; 3+ messages in thread
From: Brian Gerst @ 2002-08-03 22:39 UTC (permalink / raw)
To: Linus Torvalds; +Cc: Linux-Kernel
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This patch removes an artifact of code left over from the 2.0 days when
the kernel didn't use flat segments.
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diff -urN linux-2.5.30/arch/i386/kernel/process.c linux/arch/i386/kernel/process.c
--- linux-2.5.30/arch/i386/kernel/process.c Fri Aug 2 10:15:28 2002
+++ linux/arch/i386/kernel/process.c Sat Aug 3 16:41:03 2002
@@ -313,11 +313,6 @@
memcpy (swapper_pg_dir, swapper_pg_dir + USER_PGD_PTRS,
sizeof (swapper_pg_dir [0]) * KERNEL_PGD_PTRS);
- /* Make sure the first page is mapped to the start of physical memory.
- It is normally not mapped, to trap kernel NULL pointer dereferences. */
-
- pg0[0] = _PAGE_RW | _PAGE_PRESENT;
-
/*
* Use `swapper_pg_dir' as our page directory.
*/
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] Dead code in i386/kernel/process.c
2002-08-03 22:39 [PATCH] Dead code in i386/kernel/process.c Brian Gerst
@ 2002-08-03 23:09 ` Brian Gerst
2002-08-04 15:45 ` Jamie Lokier
1 sibling, 0 replies; 3+ messages in thread
From: Brian Gerst @ 2002-08-03 23:09 UTC (permalink / raw)
To: Linus Torvalds; +Cc: Linux-Kernel
Brian Gerst wrote:
> This patch removes an artifact of code left over from the 2.0 days when
> the kernel didn't use flat segments.
>
>
> ------------------------------------------------------------------------
>
> diff -urN linux-2.5.30/arch/i386/kernel/process.c linux/arch/i386/kernel/process.c
> --- linux-2.5.30/arch/i386/kernel/process.c Fri Aug 2 10:15:28 2002
> +++ linux/arch/i386/kernel/process.c Sat Aug 3 16:41:03 2002
> @@ -313,11 +313,6 @@
> memcpy (swapper_pg_dir, swapper_pg_dir + USER_PGD_PTRS,
> sizeof (swapper_pg_dir [0]) * KERNEL_PGD_PTRS);
>
> - /* Make sure the first page is mapped to the start of physical memory.
> - It is normally not mapped, to trap kernel NULL pointer dereferences. */
> -
> - pg0[0] = _PAGE_RW | _PAGE_PRESENT;
> -
> /*
> * Use `swapper_pg_dir' as our page directory.
> */
I should clarify that the dead code does the same thing as the preceding
memcpy.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] Dead code in i386/kernel/process.c
2002-08-03 22:39 [PATCH] Dead code in i386/kernel/process.c Brian Gerst
2002-08-03 23:09 ` Brian Gerst
@ 2002-08-04 15:45 ` Jamie Lokier
1 sibling, 0 replies; 3+ messages in thread
From: Jamie Lokier @ 2002-08-04 15:45 UTC (permalink / raw)
To: Brian Gerst; +Cc: Linus Torvalds, Linux-Kernel
Brian Gerst wrote:
> This patch removes an artifact of code left over from the 2.0 days when
> the kernel didn't use flat segments.
This code dates back to a patch for 1.2.8 :-)
The comment is quite wrong now.
Can we trust that arch/i386/mm/init.c will continue to map the page at
0xc0000000 (PAGE_OFFSET) to physical address 0? I guess so, hence the
patch is fine.
-- Jamie
^ permalink raw reply [flat|nested] 3+ messages in thread
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2002-08-03 22:39 [PATCH] Dead code in i386/kernel/process.c Brian Gerst
2002-08-03 23:09 ` Brian Gerst
2002-08-04 15:45 ` Jamie Lokier
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