Messages in this thread Patch in this message | | | Date | Sun, 12 Jan 2003 17:05:59 +0100 (MET) | From | Mikael Pettersson <> | Subject | Re: 2.5.55/.56 instant reboot problem on 486 |
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On Sat, 11 Jan 2003 20:17:19 -0800 (PST), Linus Torvalds wrote: >On Sun, 12 Jan 2003, Mikael Pettersson wrote: >> >> My '94 vintage 486 has problems booting 2.5.55 and 2.5.56. > >Should I take it that 2.5.54 works? Or you haven't tested? >... >Ho humm.. Sounds like the non-PSE case is broken. Which should probably >mean that even newer CPU's should show the same thing if we boot with >"mem=nopentium". Can you verify that with your other machine that >otherwise boots the same kernel fine?
2.5.54 works, but since the bug in 2.5.55/.56 is dependent on kernel size, and since I couldn't find anything in patch-2.5.55 to explain the change in behaviour, I suspected that the bug has been around a bit longer: I just didn't manage to trigger it.
mem=nopentium made no difference for the other machine: it still managed to boot the same kernel the 486 failed to boot.
However, with the patch to one_page_table_init() that Brian Gerst posted earlier today (included below), my 486 boots 2.5.56 Ok.
/Mikael
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); } /* - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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