include/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 #ifdef CONFIG_X86_PAE
  12 /* Xen machine address */
  13 typedef struct xmaddr {
  14         unsigned long long maddr;
  15 } xmaddr_t;
  16
  17 /* Xen pseudo-physical address */
  18 typedef struct xpaddr {
  19         unsigned long long paddr;
  20 } xpaddr_t;
  21 #else
  22 /* Xen machine address */
  23 typedef struct xmaddr {
  24         unsigned long maddr;
  25 } xmaddr_t;
  26
  27 /* Xen pseudo-physical address */
  28 typedef struct xpaddr {
  29         unsigned long paddr;
  30 } xpaddr_t;
  31 #endif
  32
  33 #define XMADDR(x)       ((xmaddr_t) { .maddr = (x) })
  34 #define XPADDR(x)       ((xpaddr_t) { .paddr = (x) })
  35
  36 /**** MACHINE <-> PHYSICAL CONVERSION MACROS ****/
  37 #define INVALID_P2M_ENTRY       (~0UL)
  38 #define FOREIGN_FRAME_BIT       (1UL<<31)
  39 #define FOREIGN_FRAME(m)        ((m) | FOREIGN_FRAME_BIT)
  40
  41 extern unsigned long *phys_to_machine_mapping;
  42
  43 static inline unsigned long pfn_to_mfn(unsigned long pfn)
  44 {
  45         if (xen_feature(XENFEAT_auto_translated_physmap))
  46                 return pfn;
  47
  48         return phys_to_machine_mapping[(unsigned int)(pfn)] &
  49                 ~FOREIGN_FRAME_BIT;
  50 }
  51
  52 static inline int phys_to_machine_mapping_valid(unsigned long pfn)
  53 {
  54         if (xen_feature(XENFEAT_auto_translated_physmap))
  55                 return 1;
  56
  57         return (phys_to_machine_mapping[pfn] != INVALID_P2M_ENTRY);
  58 }
  59
  60 static inline unsigned long mfn_to_pfn(unsigned long mfn)
  61 {
  62         unsigned long pfn;
  63
  64         if (xen_feature(XENFEAT_auto_translated_physmap))
  65                 return mfn;
  66
  67 #if 0
  68         if (unlikely((mfn >> machine_to_phys_order) != 0))
  69                 return max_mapnr;
  70 #endif
  71
  72         pfn = 0;
  73         /*
  74          * The array access can fail (e.g., device space beyond end of RAM).
  75          * In such cases it doesn't matter what we return (we return garbage),
  76          * but we must handle the fault without crashing!
  77          */
  78         __get_user(pfn, &machine_to_phys_mapping[mfn]);
  79
  80         return pfn;
  81 }
  82
  83 static inline xmaddr_t phys_to_machine(xpaddr_t phys)
  84 {
  85         unsigned offset = phys.paddr & ~PAGE_MASK;
  86         return XMADDR(PFN_PHYS((u64)pfn_to_mfn(PFN_DOWN(phys.paddr))) | offset);
  87 }
  88
  89 static inline xpaddr_t machine_to_phys(xmaddr_t machine)
  90 {
  91         unsigned offset = machine.maddr & ~PAGE_MASK;
  92         return XPADDR(PFN_PHYS((u64)mfn_to_pfn(PFN_DOWN(machine.maddr))) | offset);
  93 }
  94
  95 /*
  96  * We detect special mappings in one of two ways:
  97  *  1. If the MFN is an I/O page then Xen will set the m2p entry
  98  *     to be outside our maximum possible pseudophys range.
  99  *  2. If the MFN belongs to a different domain then we will certainly
 100  *     not have MFN in our p2m table. Conversely, if the page is ours,
 101  *     then we'll have p2m(m2p(MFN))==MFN.
 102  * If we detect a special mapping then it doesn't have a 'struct page'.
 103  * We force !pfn_valid() by returning an out-of-range pointer.
 104  *
 105  * NB. These checks require that, for any MFN that is not in our reservation,
 106  * there is no PFN such that p2m(PFN) == MFN. Otherwise we can get confused if
 107  * we are foreign-mapping the MFN, and the other domain as m2p(MFN) == PFN.
 108  * Yikes! Various places must poke in INVALID_P2M_ENTRY for safety.
 109  *
 110  * NB2. When deliberately mapping foreign pages into the p2m table, you *must*
 111  *      use FOREIGN_FRAME(). This will cause pte_pfn() to choke on it, as we
 112  *      require. In all the cases we care about, the FOREIGN_FRAME bit is
 113  *      masked (e.g., pfn_to_mfn()) so behaviour there is correct.
 114  */
 115 static inline unsigned long mfn_to_local_pfn(unsigned long mfn)
 116 {
 117         extern unsigned long max_mapnr;
 118         unsigned long pfn = mfn_to_pfn(mfn);
 119         if ((pfn < max_mapnr)
 120             && !xen_feature(XENFEAT_auto_translated_physmap)
 121             && (phys_to_machine_mapping[pfn] != mfn))
 122                 return max_mapnr; /* force !pfn_valid() */
 123         return pfn;
 124 }
 125
 126 static inline void set_phys_to_machine(unsigned long pfn, unsigned long mfn)
 127 {
 128         if (xen_feature(XENFEAT_auto_translated_physmap)) {
 129                 BUG_ON(pfn != mfn && mfn != INVALID_P2M_ENTRY);
 130                 return;
 131         }
 132         phys_to_machine_mapping[pfn] = mfn;
 133 }
 134
 135 /* VIRT <-> MACHINE conversion */
 136 #define virt_to_machine(v)      (phys_to_machine(XPADDR(__pa(v))))
 137 #define virt_to_mfn(v)          (pfn_to_mfn(PFN_DOWN(__pa(v))))
 138 #define mfn_to_virt(m)          (__va(mfn_to_pfn(m) << PAGE_SHIFT))
 139
 140 #ifdef CONFIG_X86_PAE
 141 #define pte_mfn(_pte) (((_pte).pte_low >> PAGE_SHIFT) |                 \
 142                        (((_pte).pte_high & 0xfff) << (32-PAGE_SHIFT)))
 143
 144 static inline pte_t mfn_pte(unsigned long page_nr, pgprot_t pgprot)
 145 {
 146         pte_t pte;
 147
 148         pte.pte_high = (page_nr >> (32 - PAGE_SHIFT)) |
 149                 (pgprot_val(pgprot) >> 32);
 150         pte.pte_high &= (__supported_pte_mask >> 32);
 151         pte.pte_low = ((page_nr << PAGE_SHIFT) | pgprot_val(pgprot));
 152         pte.pte_low &= __supported_pte_mask;
 153
 154         return pte;
 155 }
 156
 157 static inline unsigned long long pte_val_ma(pte_t x)
 158 {
 159         return x.pte;
 160 }
 161 #define pmd_val_ma(v) ((v).pmd)
 162 #define pud_val_ma(v) ((v).pgd.pgd)
 163 #define __pte_ma(x)     ((pte_t) { .pte = (x) })
 164 #define __pmd_ma(x)     ((pmd_t) { (x) } )
 165 #else  /* !X86_PAE */
 166 #define pte_mfn(_pte) ((_pte).pte_low >> PAGE_SHIFT)
 167 #define mfn_pte(pfn, prot)      __pte_ma(((pfn) << PAGE_SHIFT) | pgprot_val(prot))
 168 #define pte_val_ma(x)   ((x).pte)
 169 #define pmd_val_ma(v)   ((v).pud.pgd.pgd)
 170 #define __pte_ma(x)     ((pte_t) { (x) } )
 171 #endif  /* CONFIG_X86_PAE */
 172
 173 #define pgd_val_ma(x)   ((x).pgd)
 174
 175
 176 xmaddr_t arbitrary_virt_to_machine(unsigned long address);
 177 void make_lowmem_page_readonly(void *vaddr);
 178 void make_lowmem_page_readwrite(void *vaddr);
 179
 180 #endif /* __XEN_PAGE_H */