forked from Minki/linux
4983439676
With the introduction of the .brk section, special care must be taken that no unused page table entries remain if _brk_end and _end are separated by a 2M page boundary. cleanup_highmap() runs very early and hence cannot take care of that, hence potential entries needing to be removed past _brk_end must be cleared once the brk allocator has done its job. [ Impact: avoids undesirable TLB aliases ] Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
410 lines
10 KiB
C
410 lines
10 KiB
C
#include <linux/ioport.h>
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#include <linux/swap.h>
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#include <asm/cacheflush.h>
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#include <asm/e820.h>
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#include <asm/init.h>
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#include <asm/page.h>
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#include <asm/page_types.h>
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#include <asm/sections.h>
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#include <asm/setup.h>
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#include <asm/system.h>
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#include <asm/tlbflush.h>
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unsigned long __initdata e820_table_start;
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unsigned long __meminitdata e820_table_end;
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unsigned long __meminitdata e820_table_top;
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int after_bootmem;
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int direct_gbpages
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#ifdef CONFIG_DIRECT_GBPAGES
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= 1
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#endif
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;
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static void __init find_early_table_space(unsigned long end, int use_pse,
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int use_gbpages)
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{
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unsigned long puds, pmds, ptes, tables, start;
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puds = (end + PUD_SIZE - 1) >> PUD_SHIFT;
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tables = roundup(puds * sizeof(pud_t), PAGE_SIZE);
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if (use_gbpages) {
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unsigned long extra;
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extra = end - ((end>>PUD_SHIFT) << PUD_SHIFT);
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pmds = (extra + PMD_SIZE - 1) >> PMD_SHIFT;
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} else
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pmds = (end + PMD_SIZE - 1) >> PMD_SHIFT;
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tables += roundup(pmds * sizeof(pmd_t), PAGE_SIZE);
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if (use_pse) {
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unsigned long extra;
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extra = end - ((end>>PMD_SHIFT) << PMD_SHIFT);
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#ifdef CONFIG_X86_32
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extra += PMD_SIZE;
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#endif
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ptes = (extra + PAGE_SIZE - 1) >> PAGE_SHIFT;
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} else
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ptes = (end + PAGE_SIZE - 1) >> PAGE_SHIFT;
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tables += roundup(ptes * sizeof(pte_t), PAGE_SIZE);
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#ifdef CONFIG_X86_32
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/* for fixmap */
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tables += roundup(__end_of_fixed_addresses * sizeof(pte_t), PAGE_SIZE);
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#endif
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/*
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* RED-PEN putting page tables only on node 0 could
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* cause a hotspot and fill up ZONE_DMA. The page tables
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* need roughly 0.5KB per GB.
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*/
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#ifdef CONFIG_X86_32
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start = 0x7000;
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e820_table_start = find_e820_area(start, max_pfn_mapped<<PAGE_SHIFT,
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tables, PAGE_SIZE);
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#else /* CONFIG_X86_64 */
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start = 0x8000;
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e820_table_start = find_e820_area(start, end, tables, PAGE_SIZE);
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#endif
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if (e820_table_start == -1UL)
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panic("Cannot find space for the kernel page tables");
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e820_table_start >>= PAGE_SHIFT;
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e820_table_end = e820_table_start;
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e820_table_top = e820_table_start + (tables >> PAGE_SHIFT);
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printk(KERN_DEBUG "kernel direct mapping tables up to %lx @ %lx-%lx\n",
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end, e820_table_start << PAGE_SHIFT, e820_table_top << PAGE_SHIFT);
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}
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struct map_range {
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unsigned long start;
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unsigned long end;
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unsigned page_size_mask;
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};
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#ifdef CONFIG_X86_32
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#define NR_RANGE_MR 3
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#else /* CONFIG_X86_64 */
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#define NR_RANGE_MR 5
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#endif
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static int __meminit save_mr(struct map_range *mr, int nr_range,
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unsigned long start_pfn, unsigned long end_pfn,
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unsigned long page_size_mask)
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{
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if (start_pfn < end_pfn) {
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if (nr_range >= NR_RANGE_MR)
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panic("run out of range for init_memory_mapping\n");
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mr[nr_range].start = start_pfn<<PAGE_SHIFT;
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mr[nr_range].end = end_pfn<<PAGE_SHIFT;
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mr[nr_range].page_size_mask = page_size_mask;
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nr_range++;
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}
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return nr_range;
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}
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#ifdef CONFIG_X86_64
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static void __init init_gbpages(void)
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{
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if (direct_gbpages && cpu_has_gbpages)
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printk(KERN_INFO "Using GB pages for direct mapping\n");
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else
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direct_gbpages = 0;
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}
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#else
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static inline void init_gbpages(void)
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{
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}
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#endif
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/*
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* Setup the direct mapping of the physical memory at PAGE_OFFSET.
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* This runs before bootmem is initialized and gets pages directly from
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* the physical memory. To access them they are temporarily mapped.
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*/
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unsigned long __init_refok init_memory_mapping(unsigned long start,
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unsigned long end)
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{
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unsigned long page_size_mask = 0;
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unsigned long start_pfn, end_pfn;
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unsigned long ret = 0;
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unsigned long pos;
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struct map_range mr[NR_RANGE_MR];
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int nr_range, i;
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int use_pse, use_gbpages;
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printk(KERN_INFO "init_memory_mapping: %016lx-%016lx\n", start, end);
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if (!after_bootmem)
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init_gbpages();
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#ifdef CONFIG_DEBUG_PAGEALLOC
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/*
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* For CONFIG_DEBUG_PAGEALLOC, identity mapping will use small pages.
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* This will simplify cpa(), which otherwise needs to support splitting
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* large pages into small in interrupt context, etc.
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*/
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use_pse = use_gbpages = 0;
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#else
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use_pse = cpu_has_pse;
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use_gbpages = direct_gbpages;
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#endif
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#ifdef CONFIG_X86_32
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#ifdef CONFIG_X86_PAE
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set_nx();
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if (nx_enabled)
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printk(KERN_INFO "NX (Execute Disable) protection: active\n");
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#endif
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/* Enable PSE if available */
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if (cpu_has_pse)
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set_in_cr4(X86_CR4_PSE);
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/* Enable PGE if available */
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if (cpu_has_pge) {
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set_in_cr4(X86_CR4_PGE);
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__supported_pte_mask |= _PAGE_GLOBAL;
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}
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#endif
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if (use_gbpages)
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page_size_mask |= 1 << PG_LEVEL_1G;
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if (use_pse)
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page_size_mask |= 1 << PG_LEVEL_2M;
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memset(mr, 0, sizeof(mr));
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nr_range = 0;
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/* head if not big page alignment ? */
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start_pfn = start >> PAGE_SHIFT;
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pos = start_pfn << PAGE_SHIFT;
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#ifdef CONFIG_X86_32
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/*
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* Don't use a large page for the first 2/4MB of memory
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* because there are often fixed size MTRRs in there
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* and overlapping MTRRs into large pages can cause
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* slowdowns.
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*/
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if (pos == 0)
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end_pfn = 1<<(PMD_SHIFT - PAGE_SHIFT);
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else
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end_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
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<< (PMD_SHIFT - PAGE_SHIFT);
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#else /* CONFIG_X86_64 */
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end_pfn = ((pos + (PMD_SIZE - 1)) >> PMD_SHIFT)
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<< (PMD_SHIFT - PAGE_SHIFT);
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#endif
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if (end_pfn > (end >> PAGE_SHIFT))
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end_pfn = end >> PAGE_SHIFT;
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if (start_pfn < end_pfn) {
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nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
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pos = end_pfn << PAGE_SHIFT;
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}
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/* big page (2M) range */
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start_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
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<< (PMD_SHIFT - PAGE_SHIFT);
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#ifdef CONFIG_X86_32
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end_pfn = (end>>PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
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#else /* CONFIG_X86_64 */
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end_pfn = ((pos + (PUD_SIZE - 1))>>PUD_SHIFT)
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<< (PUD_SHIFT - PAGE_SHIFT);
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if (end_pfn > ((end>>PMD_SHIFT)<<(PMD_SHIFT - PAGE_SHIFT)))
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end_pfn = ((end>>PMD_SHIFT)<<(PMD_SHIFT - PAGE_SHIFT));
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#endif
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if (start_pfn < end_pfn) {
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nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
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page_size_mask & (1<<PG_LEVEL_2M));
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pos = end_pfn << PAGE_SHIFT;
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}
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#ifdef CONFIG_X86_64
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/* big page (1G) range */
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start_pfn = ((pos + (PUD_SIZE - 1))>>PUD_SHIFT)
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<< (PUD_SHIFT - PAGE_SHIFT);
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end_pfn = (end >> PUD_SHIFT) << (PUD_SHIFT - PAGE_SHIFT);
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if (start_pfn < end_pfn) {
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nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
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page_size_mask &
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((1<<PG_LEVEL_2M)|(1<<PG_LEVEL_1G)));
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pos = end_pfn << PAGE_SHIFT;
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}
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/* tail is not big page (1G) alignment */
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start_pfn = ((pos + (PMD_SIZE - 1))>>PMD_SHIFT)
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<< (PMD_SHIFT - PAGE_SHIFT);
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end_pfn = (end >> PMD_SHIFT) << (PMD_SHIFT - PAGE_SHIFT);
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if (start_pfn < end_pfn) {
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nr_range = save_mr(mr, nr_range, start_pfn, end_pfn,
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page_size_mask & (1<<PG_LEVEL_2M));
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pos = end_pfn << PAGE_SHIFT;
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}
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#endif
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/* tail is not big page (2M) alignment */
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start_pfn = pos>>PAGE_SHIFT;
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end_pfn = end>>PAGE_SHIFT;
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nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0);
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/* try to merge same page size and continuous */
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for (i = 0; nr_range > 1 && i < nr_range - 1; i++) {
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unsigned long old_start;
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if (mr[i].end != mr[i+1].start ||
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mr[i].page_size_mask != mr[i+1].page_size_mask)
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continue;
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/* move it */
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old_start = mr[i].start;
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memmove(&mr[i], &mr[i+1],
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(nr_range - 1 - i) * sizeof(struct map_range));
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mr[i--].start = old_start;
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nr_range--;
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}
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for (i = 0; i < nr_range; i++)
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printk(KERN_DEBUG " %010lx - %010lx page %s\n",
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mr[i].start, mr[i].end,
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(mr[i].page_size_mask & (1<<PG_LEVEL_1G))?"1G":(
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(mr[i].page_size_mask & (1<<PG_LEVEL_2M))?"2M":"4k"));
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/*
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* Find space for the kernel direct mapping tables.
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*
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* Later we should allocate these tables in the local node of the
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* memory mapped. Unfortunately this is done currently before the
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* nodes are discovered.
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*/
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if (!after_bootmem)
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find_early_table_space(end, use_pse, use_gbpages);
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#ifdef CONFIG_X86_32
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for (i = 0; i < nr_range; i++)
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kernel_physical_mapping_init(mr[i].start, mr[i].end,
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mr[i].page_size_mask);
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ret = end;
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#else /* CONFIG_X86_64 */
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for (i = 0; i < nr_range; i++)
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ret = kernel_physical_mapping_init(mr[i].start, mr[i].end,
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mr[i].page_size_mask);
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#endif
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#ifdef CONFIG_X86_32
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early_ioremap_page_table_range_init();
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load_cr3(swapper_pg_dir);
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#endif
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#ifdef CONFIG_X86_64
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if (!after_bootmem && !start) {
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pud_t *pud;
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pmd_t *pmd;
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mmu_cr4_features = read_cr4();
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/*
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* _brk_end cannot change anymore, but it and _end may be
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* located on different 2M pages. cleanup_highmap(), however,
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* can only consider _end when it runs, so destroy any
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* mappings beyond _brk_end here.
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*/
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pud = pud_offset(pgd_offset_k(_brk_end), _brk_end);
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pmd = pmd_offset(pud, _brk_end - 1);
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while (++pmd <= pmd_offset(pud, (unsigned long)_end - 1))
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pmd_clear(pmd);
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}
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#endif
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__flush_tlb_all();
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if (!after_bootmem && e820_table_end > e820_table_start)
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reserve_early(e820_table_start << PAGE_SHIFT,
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e820_table_end << PAGE_SHIFT, "PGTABLE");
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if (!after_bootmem)
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early_memtest(start, end);
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return ret >> PAGE_SHIFT;
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}
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/*
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* devmem_is_allowed() checks to see if /dev/mem access to a certain address
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* is valid. The argument is a physical page number.
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*
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*
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* On x86, access has to be given to the first megabyte of ram because that area
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* contains bios code and data regions used by X and dosemu and similar apps.
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* Access has to be given to non-kernel-ram areas as well, these contain the PCI
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* mmio resources as well as potential bios/acpi data regions.
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*/
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int devmem_is_allowed(unsigned long pagenr)
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{
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if (pagenr <= 256)
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return 1;
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if (iomem_is_exclusive(pagenr << PAGE_SHIFT))
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return 0;
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if (!page_is_ram(pagenr))
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return 1;
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return 0;
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}
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void free_init_pages(char *what, unsigned long begin, unsigned long end)
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{
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unsigned long addr = begin;
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if (addr >= end)
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return;
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/*
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* If debugging page accesses then do not free this memory but
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* mark them not present - any buggy init-section access will
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* create a kernel page fault:
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*/
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#ifdef CONFIG_DEBUG_PAGEALLOC
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printk(KERN_INFO "debug: unmapping init memory %08lx..%08lx\n",
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begin, PAGE_ALIGN(end));
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set_memory_np(begin, (end - begin) >> PAGE_SHIFT);
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#else
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/*
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* We just marked the kernel text read only above, now that
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* we are going to free part of that, we need to make that
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* writeable first.
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*/
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set_memory_rw(begin, (end - begin) >> PAGE_SHIFT);
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printk(KERN_INFO "Freeing %s: %luk freed\n", what, (end - begin) >> 10);
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for (; addr < end; addr += PAGE_SIZE) {
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ClearPageReserved(virt_to_page(addr));
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init_page_count(virt_to_page(addr));
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memset((void *)(addr & ~(PAGE_SIZE-1)),
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POISON_FREE_INITMEM, PAGE_SIZE);
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free_page(addr);
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totalram_pages++;
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}
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#endif
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}
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void free_initmem(void)
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{
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free_init_pages("unused kernel memory",
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(unsigned long)(&__init_begin),
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(unsigned long)(&__init_end));
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}
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#ifdef CONFIG_BLK_DEV_INITRD
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void free_initrd_mem(unsigned long start, unsigned long end)
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{
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free_init_pages("initrd memory", start, end);
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}
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#endif
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