forked from Minki/linux
dcb32d9913
The page table manipulation code seems to have grown a couple of sites that are looking for empty PTEs. Just in case one of these entries got a stray bit set, use pte_none() instead of checking for a zero pte_val(). The use pte_same() makes me a bit nervous. If we were doing a pte_same() check against two cleared entries and one of them had a stray bit set, it might fail the pte_same() check. But, I don't think we ever _do_ pte_same() for cleared entries. It is almost entirely used for checking for races in fault-in paths. Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Hansen <dave@sr71.net> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Luis R. Rodriguez <mcgrof@suse.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Toshi Kani <toshi.kani@hp.com> Cc: dave.hansen@intel.com Cc: linux-mm@kvack.org Cc: mhocko@suse.com Link: http://lkml.kernel.org/r/20160708001915.813703D9@viggo.jf.intel.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
99 lines
2.1 KiB
C
99 lines
2.1 KiB
C
#include <linux/sched.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/mm.h>
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#include <linux/nmi.h>
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#include <linux/swap.h>
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#include <linux/smp.h>
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#include <linux/highmem.h>
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#include <linux/pagemap.h>
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#include <linux/spinlock.h>
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#include <linux/module.h>
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#include <asm/pgtable.h>
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#include <asm/pgalloc.h>
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#include <asm/fixmap.h>
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#include <asm/e820.h>
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#include <asm/tlb.h>
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#include <asm/tlbflush.h>
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#include <asm/io.h>
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unsigned int __VMALLOC_RESERVE = 128 << 20;
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/*
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* Associate a virtual page frame with a given physical page frame
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* and protection flags for that frame.
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*/
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void set_pte_vaddr(unsigned long vaddr, pte_t pteval)
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{
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pgd_t *pgd;
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pud_t *pud;
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pmd_t *pmd;
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pte_t *pte;
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pgd = swapper_pg_dir + pgd_index(vaddr);
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if (pgd_none(*pgd)) {
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BUG();
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return;
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}
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pud = pud_offset(pgd, vaddr);
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if (pud_none(*pud)) {
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BUG();
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return;
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}
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pmd = pmd_offset(pud, vaddr);
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if (pmd_none(*pmd)) {
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BUG();
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return;
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}
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pte = pte_offset_kernel(pmd, vaddr);
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if (!pte_none(pteval))
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set_pte_at(&init_mm, vaddr, pte, pteval);
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else
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pte_clear(&init_mm, vaddr, pte);
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/*
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* It's enough to flush this one mapping.
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* (PGE mappings get flushed as well)
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*/
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__flush_tlb_one(vaddr);
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}
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unsigned long __FIXADDR_TOP = 0xfffff000;
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EXPORT_SYMBOL(__FIXADDR_TOP);
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/*
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* vmalloc=size forces the vmalloc area to be exactly 'size'
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* bytes. This can be used to increase (or decrease) the
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* vmalloc area - the default is 128m.
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*/
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static int __init parse_vmalloc(char *arg)
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{
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if (!arg)
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return -EINVAL;
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/* Add VMALLOC_OFFSET to the parsed value due to vm area guard hole*/
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__VMALLOC_RESERVE = memparse(arg, &arg) + VMALLOC_OFFSET;
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return 0;
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}
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early_param("vmalloc", parse_vmalloc);
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/*
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* reservetop=size reserves a hole at the top of the kernel address space which
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* a hypervisor can load into later. Needed for dynamically loaded hypervisors,
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* so relocating the fixmap can be done before paging initialization.
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*/
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static int __init parse_reservetop(char *arg)
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{
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unsigned long address;
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if (!arg)
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return -EINVAL;
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address = memparse(arg, &arg);
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reserve_top_address(address);
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early_ioremap_init();
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return 0;
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}
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early_param("reservetop", parse_reservetop);
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