include/asm-x86/xen/page.h

   1 #ifndef __XEN_PAGE_H
   2 #define __XEN_PAGE_H
   3
   4 #include <linux/pfn.h>
   5
   6 #include <asm/uaccess.h>
   7 #include <asm/pgtable.h>
   8
   9 #include <xen/features.h>
  10
  11 /* Xen machine address */
  12 typedef struct xmaddr {
  13         phys_addr_t maddr;
  14 } xmaddr_t;
  15
  16 /* Xen pseudo-physical address */
  17 typedef struct xpaddr {
  18         phys_addr_t paddr;
  19 } xpaddr_t;
  20
  21 #define XMADDR(x)       ((xmaddr_t) { .maddr = (x) })
  22 #define XPADDR(x)       ((xpaddr_t) { .paddr = (x) })
  23
  24 /**** MACHINE <-> PHYSICAL CONVERSION MACROS ****/
  25 #define INVALID_P2M_ENTRY       (~0UL)
  26 #define FOREIGN_FRAME_BIT       (1UL<<31)
  27 #define FOREIGN_FRAME(m)        ((m) | FOREIGN_FRAME_BIT)
  28
  29 extern unsigned long *phys_to_machine_mapping;
  30
  31 static inline unsigned long pfn_to_mfn(unsigned long pfn)
  32 {
  33         if (xen_feature(XENFEAT_auto_translated_physmap))
  34                 return pfn;
  35
  36         return phys_to_machine_mapping[(unsigned int)(pfn)] &
  37                 ~FOREIGN_FRAME_BIT;
  38 }
  39
  40 static inline int phys_to_machine_mapping_valid(unsigned long pfn)
  41 {
  42         if (xen_feature(XENFEAT_auto_translated_physmap))
  43                 return 1;
  44
  45         return (phys_to_machine_mapping[pfn] != INVALID_P2M_ENTRY);
  46 }
  47
  48 static inline unsigned long mfn_to_pfn(unsigned long mfn)
  49 {
  50         unsigned long pfn;
  51
  52         if (xen_feature(XENFEAT_auto_translated_physmap))
  53                 return mfn;
  54
  55 #if 0
  56         if (unlikely((mfn >> machine_to_phys_order) != 0))
  57                 return max_mapnr;
  58 #endif
  59
  60         pfn = 0;
  61         /*
  62          * The array access can fail (e.g., device space beyond end of RAM).
  63          * In such cases it doesn't matter what we return (we return garbage),
  64          * but we must handle the fault without crashing!
  65          */
  66         __get_user(pfn, &machine_to_phys_mapping[mfn]);
  67
  68         return pfn;
  69 }
  70
  71 static inline xmaddr_t phys_to_machine(xpaddr_t phys)
  72 {
  73         unsigned offset = phys.paddr & ~PAGE_MASK;
  74         return XMADDR(PFN_PHYS((u64)pfn_to_mfn(PFN_DOWN(phys.paddr))) | offset);
  75 }
  76
  77 static inline xpaddr_t machine_to_phys(xmaddr_t machine)
  78 {
  79         unsigned offset = machine.maddr & ~PAGE_MASK;
  80         return XPADDR(PFN_PHYS((u64)mfn_to_pfn(PFN_DOWN(machine.maddr))) | offset);
  81 }
  82
  83 /*
  84  * We detect special mappings in one of two ways:
  85  *  1. If the MFN is an I/O page then Xen will set the m2p entry
  86  *     to be outside our maximum possible pseudophys range.
  87  *  2. If the MFN belongs to a different domain then we will certainly
  88  *     not have MFN in our p2m table. Conversely, if the page is ours,
  89  *     then we'll have p2m(m2p(MFN))==MFN.
  90  * If we detect a special mapping then it doesn't have a 'struct page'.
  91  * We force !pfn_valid() by returning an out-of-range pointer.
  92  *
  93  * NB. These checks require that, for any MFN that is not in our reservation,
  94  * there is no PFN such that p2m(PFN) == MFN. Otherwise we can get confused if
  95  * we are foreign-mapping the MFN, and the other domain as m2p(MFN) == PFN.
  96  * Yikes! Various places must poke in INVALID_P2M_ENTRY for safety.
  97  *
  98  * NB2. When deliberately mapping foreign pages into the p2m table, you *must*
  99  *      use FOREIGN_FRAME(). This will cause pte_pfn() to choke on it, as we
 100  *      require. In all the cases we care about, the FOREIGN_FRAME bit is
 101  *      masked (e.g., pfn_to_mfn()) so behaviour there is correct.
 102  */
 103 static inline unsigned long mfn_to_local_pfn(unsigned long mfn)
 104 {
 105         extern unsigned long max_mapnr;
 106         unsigned long pfn = mfn_to_pfn(mfn);
 107         if ((pfn < max_mapnr)
 108             && !xen_feature(XENFEAT_auto_translated_physmap)
 109             && (phys_to_machine_mapping[pfn] != mfn))
 110                 return max_mapnr; /* force !pfn_valid() */
 111         return pfn;
 112 }
 113
 114 static inline void set_phys_to_machine(unsigned long pfn, unsigned long mfn)
 115 {
 116         if (xen_feature(XENFEAT_auto_translated_physmap)) {
 117                 BUG_ON(pfn != mfn && mfn != INVALID_P2M_ENTRY);
 118                 return;
 119         }
 120         phys_to_machine_mapping[pfn] = mfn;
 121 }
 122
 123 /* VIRT <-> MACHINE conversion */
 124 #define virt_to_machine(v)      (phys_to_machine(XPADDR(__pa(v))))
 125 #define virt_to_mfn(v)          (pfn_to_mfn(PFN_DOWN(__pa(v))))
 126 #define mfn_to_virt(m)          (__va(mfn_to_pfn(m) << PAGE_SHIFT))
 127
 128 static inline unsigned long pte_mfn(pte_t pte)
 129 {
 130         return (pte.pte & PTE_MASK) >> PAGE_SHIFT;
 131 }
 132
 133 static inline pte_t mfn_pte(unsigned long page_nr, pgprot_t pgprot)
 134 {
 135         pte_t pte;
 136
 137         pte.pte = ((phys_addr_t)page_nr << PAGE_SHIFT) |
 138                 (pgprot_val(pgprot) & __supported_pte_mask);
 139
 140         return pte;
 141 }
 142
 143 static inline pteval_t pte_val_ma(pte_t pte)
 144 {
 145         return pte.pte;
 146 }
 147
 148 static inline pte_t __pte_ma(pteval_t x)
 149 {
 150         return (pte_t) { .pte = x };
 151 }
 152
 153 #define pmd_val_ma(v) ((v).pmd)
 154 #define pud_val_ma(v) ((v).pgd.pgd)
 155 #define __pmd_ma(x)     ((pmd_t) { (x) } )
 156
 157 #define pgd_val_ma(x)   ((x).pgd)
 158
 159
 160 xmaddr_t arbitrary_virt_to_machine(unsigned long address);
 161 void make_lowmem_page_readonly(void *vaddr);
 162 void make_lowmem_page_readwrite(void *vaddr);
 163
 164 #endif /* __XEN_PAGE_H */