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Commit 73159fdc authored by Andy Lutomirski's avatar Andy Lutomirski Committed by H. Peter Anvin
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x86, mm: Ensure correct alignment of the fixmap 



The early_ioremap code requires that its buffers not span a PMD
boundary.  The logic for ensuring that only works if the fixmap is
aligned, so assert that it's aligned correctly.

To make this work reliably, reserve_top_address needs to be
adjusted.

Signed-off-by: default avatarAndy Lutomirski <luto@amacapital.net>
Link: http://lkml.kernel.org/r/e59a5f4362661f75dd4841fa74e1f2448045e245.1399317206.git.luto@amacapital.net


Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
parent 89ca3b88

arch/x86/mm/ioremap.c

+6 −0
Original line number Diff line number Diff line
@@ -355,6 +355,12 @@ void __init early_ioremap_init(void) 
{

	pmd_t *pmd;



#ifdef CONFIG_X86_64

	BUILD_BUG_ON((fix_to_virt(0) + PAGE_SIZE) & ((1 << PMD_SHIFT) - 1));

#else

	WARN_ON((fix_to_virt(0) + PAGE_SIZE) & ((1 << PMD_SHIFT) - 1));

#endif



	early_ioremap_setup();



	pmd = early_ioremap_pmd(fix_to_virt(FIX_BTMAP_BEGIN));

arch/x86/mm/pgtable.c

+3 −3
Original line number Diff line number Diff line
@@ -449,9 +449,9 @@ void __init reserve_top_address(unsigned long reserve) 
{

#ifdef CONFIG_X86_32

	BUG_ON(fixmaps_set > 0);

	printk(KERN_INFO "Reserving virtual address space above 0x%08x\n",

	       (int)-reserve);

	__FIXADDR_TOP = -reserve - PAGE_SIZE;

	__FIXADDR_TOP = round_down(-reserve, 1 << PMD_SHIFT) - PAGE_SIZE;

	printk(KERN_INFO "Reserving virtual address space above 0x%08lx (rounded to 0x%08lx)\n",

	       -reserve, __FIXADDR_TOP + PAGE_SIZE);

#endif

}