Re: 2.5.55/.56 instant reboot problem on 486

[Bill Davidsen]

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On Sun, 12 Jan 2003, Brian Gerst wrote:

> The problem is that one_page_table_init() pulls the rug out from under 
> the kernel by installing a new page table before setting it up.  A 486 
> has a small TLB so any miss will cause a triple fault and reset.  Try 
> this patch and see if it fixes it.

As someone who uses 486's for routers on occasion, thank you!

-- 
bill davidsen <[e-mail]>
  CTO, TMR Associates, Inc
Doing interesting things with little computers since 1979.

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diff -urN linux-2.5.56/arch/i386/mm/init.c linux/arch/i386/mm/init.c
--- linux-2.5.56/arch/i386/mm/init.c	Sun Jan 12 00:16:22 2003
+++ linux/arch/i386/mm/init.c	Sun Jan 12 01:48:28 2003
@@ -71,12 +71,16 @@
  */
 static pte_t * __init one_page_table_init(pmd_t *pmd)
 {
-	pte_t *page_table = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
-	set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
-	if (page_table != pte_offset_kernel(pmd, 0))
-		BUG();	
+	if (pmd_none(*pmd)) {
+		pte_t *page_table = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE);
+		set_pmd(pmd, __pmd(__pa(page_table) | _PAGE_TABLE));
+		if (page_table != pte_offset_kernel(pmd, 0))
+			BUG();	
 
-	return page_table;
+		return page_table;
+	}
+	
+	return pte_offset_kernel(pmd, 0);
 }
 
 /*

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