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Commit 844ab6f9 authored by Jacob Shin's avatar Jacob Shin Committed by H. Peter Anvin
Browse files

x86, mm: Find_early_table_space based on ranges that are actually being mapped 

Current logic finds enough space for direct mapping page tables from 0
to end. Instead, we only need to find enough space to cover mr[0].start
to mr[nr_range].end -- the range that is actually being mapped by
init_memory_mapping()

This is needed after 1bbbbe77, to address
the panic reported here:

  https://lkml.org/lkml/2012/10/20/160
  https://lkml.org/lkml/2012/10/21/157



Signed-off-by: default avatarJacob Shin <jacob.shin@amd.com>
Link: http://lkml.kernel.org/r/20121024195311.GB11779@jshin-Toonie


Tested-by: default avatarTom Rini <trini@ti.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
parent 1f2ff682

arch/x86/mm/init.c

+41 −29
Original line number Diff line number Diff line
@@ -29,36 +29,54 @@ int direct_gbpages 
#endif

;



static void __init find_early_table_space(unsigned long end, int use_pse,

					  int use_gbpages)

struct map_range {

	unsigned long start;

	unsigned long end;

	unsigned page_size_mask;

};



/*

 * First calculate space needed for kernel direct mapping page tables to cover

 * mr[0].start to mr[nr_range - 1].end, while accounting for possible 2M and 1GB

 * pages. Then find enough contiguous space for those page tables.

 */

static void __init find_early_table_space(struct map_range *mr, int nr_range)

{

	unsigned long puds, pmds, ptes, tables, start = 0, good_end = end;

	int i;

	unsigned long puds = 0, pmds = 0, ptes = 0, tables;

	unsigned long start = 0, good_end;

	phys_addr_t base;



	puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;

	tables = roundup(puds * sizeof(pud_t), PAGE_SIZE);



	if (use_gbpages) {

		unsigned long extra;



		extra = end - ((end>>PUD_SHIFT) << PUD_SHIFT);

		pmds = (extra + PMD_SIZE - 1) >> PMD_SHIFT;

	} else

		pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;

	for (i = 0; i < nr_range; i++) {

		unsigned long range, extra;



	tables += roundup(pmds * sizeof(pmd_t), PAGE_SIZE);

		range = mr[i].end - mr[i].start;

		puds += (range + PUD_SIZE - 1) >> PUD_SHIFT;



	if (use_pse) {

		unsigned long extra;

		if (mr[i].page_size_mask & (1 << PG_LEVEL_1G)) {

			extra = range - ((range >> PUD_SHIFT) << PUD_SHIFT);

			pmds += (extra + PMD_SIZE - 1) >> PMD_SHIFT;

		} else {

			pmds += (range + PMD_SIZE - 1) >> PMD_SHIFT;

		}



		extra = end - ((end>>PMD_SHIFT) << PMD_SHIFT);

		if (mr[i].page_size_mask & (1 << PG_LEVEL_2M)) {

			extra = range - ((range >> PMD_SHIFT) << PMD_SHIFT);

#ifdef CONFIG_X86_32

			extra += PMD_SIZE;

#endif

		ptes = (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;

	} else

		ptes = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;

			/* The first 2/4M doesn't use large pages. */

			if (mr[i].start < PMD_SIZE)

				extra += range;



			ptes += (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;

		} else {

			ptes += (range + PAGE_SIZE - 1) >> PAGE_SHIFT;

		}

	}



	tables = roundup(puds * sizeof(pud_t), PAGE_SIZE);

	tables += roundup(pmds * sizeof(pmd_t), PAGE_SIZE);

	tables += roundup(ptes * sizeof(pte_t), PAGE_SIZE);



#ifdef CONFIG_X86_32
@@ -76,7 +94,7 @@ static void __init find_early_table_space(unsigned long end, int use_pse, 
	pgt_buf_top = pgt_buf_start + (tables >> PAGE_SHIFT);



	printk(KERN_DEBUG "kernel direct mapping tables up to %#lx @ [mem %#010lx-%#010lx]\n",

		end - 1, pgt_buf_start << PAGE_SHIFT,

		mr[nr_range - 1].end - 1, pgt_buf_start << PAGE_SHIFT,

		(pgt_buf_top << PAGE_SHIFT) - 1);

}
@@ -85,12 +103,6 @@ void __init native_pagetable_reserve(u64 start, u64 end) 
	memblock_reserve(start, end - start);

}



struct map_range {

	unsigned long start;

	unsigned long end;

	unsigned page_size_mask;

};



#ifdef CONFIG_X86_32

#define NR_RANGE_MR 3

#else /* CONFIG_X86_64 */
@@ -263,7 +275,7 @@ unsigned long __init_refok init_memory_mapping(unsigned long start, 
	 * nodes are discovered.

	 */

	if (!after_bootmem)

		find_early_table_space(end, use_pse, use_gbpages);

		find_early_table_space(mr, nr_range);



	for (i = 0; i < nr_range; i++)

		ret = kernel_physical_mapping_init(mr[i].start, mr[i].end,