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Commit 45c7b28f authored by Jeremy Fitzhardinge's avatar Jeremy Fitzhardinge Committed by Ingo Molnar
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Revert "x86: create a non-zero sized bm_pte only when needed" 



This reverts commit 698609bd.

69860 breaks Xen booting, as it relies on head*.S to set up the fixmap
pagetables (as a side-effect of initializing the USB debug port).
Xen, however, does not boot via head*.S, and so the fixmap area is
not initialized.

The specific symptom of the crash is a fault in dmi_scan(), because
the pointer that early_ioremap returns is not actually present.

Signed-off-by: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Jan Beulich <jbeulich@novell.com>
LKML-Reference: <49C43A8E.5090203@goop.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 0f350755

arch/x86/mm/ioremap.c

+3 −16
Original line number Diff line number Diff line
@@ -487,12 +487,7 @@ static int __init early_ioremap_debug_setup(char *str) 
early_param("early_ioremap_debug", early_ioremap_debug_setup);



static __initdata int after_paging_init;

#define __FIXADDR_TOP (-PAGE_SIZE)

static pte_t bm_pte[(__fix_to_virt(FIX_DBGP_BASE)

		     ^ __fix_to_virt(FIX_BTMAP_BEGIN)) >> PMD_SHIFT

		    ? PAGE_SIZE / sizeof(pte_t) : 0] __page_aligned_bss;

#undef __FIXADDR_TOP

static __initdata pte_t *bm_ptep;

static pte_t bm_pte[PAGE_SIZE/sizeof(pte_t)] __page_aligned_bss;



static inline pmd_t * __init early_ioremap_pmd(unsigned long addr)

{
@@ -507,8 +502,6 @@ static inline pmd_t * __init early_ioremap_pmd(unsigned long addr) 


static inline pte_t * __init early_ioremap_pte(unsigned long addr)

{

	if (!sizeof(bm_pte))

		return &bm_ptep[pte_index(addr)];

	return &bm_pte[pte_index(addr)];

}
@@ -526,14 +519,8 @@ void __init early_ioremap_init(void) 
		slot_virt[i] = fix_to_virt(FIX_BTMAP_BEGIN - NR_FIX_BTMAPS*i);



	pmd = early_ioremap_pmd(fix_to_virt(FIX_BTMAP_BEGIN));

	if (sizeof(bm_pte)) {

	memset(bm_pte, 0, sizeof(bm_pte));

	pmd_populate_kernel(&init_mm, pmd, bm_pte);

	} else {

		bm_ptep = pte_offset_kernel(pmd, 0);

		if (early_ioremap_debug)

			printk(KERN_INFO "bm_ptep=%p\n", bm_ptep);

	}



	/*

	 * The boot-ioremap range spans multiple pmds, for which