Messages in this thread Patch in this message | | | From | Robert Kaiser <> | Subject | [SOLVED + PATCH] Re: Anybody got 2.4.0 running on a 386 ? | Date | Mon, 15 Jan 2001 19:38:05 +0100 |
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Hi everybody,
I finally found the reason why 386es have trouble booting the 2.4.0 kernel:
In routine pagetable_init() in arch/i386/mm/init.c, a pte gets installed before it actually has been filled with valid entries. This causes the kernel text segment to be temporarily unmapped. Pentiums are only lucky to not crash because they have a bigger TLB than 386s.
Here is a patch to fix this:
--- init.c.orig Wed Nov 29 07:43:39 2000 +++ init.c Mon Jan 15 18:36:08 2001 @@ -317,7 +317,7 @@ pgd_t *pgd, *pgd_base; int i, j, k; pmd_t *pmd; - pte_t *pte; + pte_t *pte, *pte_base; /* * This can be zero as well - no problem, in that case we exit @@ -366,11 +366,7 @@ continue; } - pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE); - set_pmd(pmd, __pmd(_KERNPG_TABLE + __pa(pte))); - - if (pte != pte_offset(pmd, 0)) - BUG(); + pte_base = pte = (pte_t *) alloc_bootmem_low_pages(PAGE_SIZE); for (k = 0; k < PTRS_PER_PTE; pte++, k++) { vaddr = i*PGDIR_SIZE + j*PMD_SIZE + k*PAGE_SIZE; @@ -378,6 +374,10 @@ break; *pte = mk_pte_phys(__pa(vaddr), PAGE_KERNEL); } + set_pmd(pmd, __pmd(_KERNPG_TABLE + __pa(pte_base))); + if (pte_base != pte_offset(pmd, 0)) + BUG(); + } } Thanks to everybody who helped with ideas and suggestions, especially Ingo Molnar!
Cheers
Rob
---------------------------------------------------------------- Robert Kaiser email: rkaiser@sysgo.de SYSGO RTS GmbH Am Pfaffenstein 14 phone: (49) 6136 9948-762 D-55270 Klein-Winternheim / Germany fax: (49) 6136 9948-10 - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
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