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
   8 #include <xen/features.h>
   9
  10 #ifdef CONFIG_X86_PAE
  11 /* Xen machine address */
  12 typedef struct xmaddr {
  13         unsigned long long maddr;
  14 } xmaddr_t;
  15
  16 /* Xen pseudo-physical address */
  17 typedef struct xpaddr {
  18         unsigned long long paddr;
  19 } xpaddr_t;
  20 #else
  21 /* Xen machine address */
  22 typedef struct xmaddr {
  23         unsigned long maddr;
  24 } xmaddr_t;
  25
  26 /* Xen pseudo-physical address */
  27 typedef struct xpaddr {
  28         unsigned long paddr;
  29 } xpaddr_t;
  30 #endif
  31
  32 #define XMADDR(x)       ((xmaddr_t) { .maddr = (x) })
  33 #define XPADDR(x)       ((xpaddr_t) { .paddr = (x) })
  34
  35 /**** MACHINE <-> PHYSICAL CONVERSION MACROS ****/
  36 #define INVALID_P2M_ENTRY       (~0UL)
  37 #define FOREIGN_FRAME_BIT       (1UL<<31)
  38 #define FOREIGN_FRAME(m)        ((m) | FOREIGN_FRAME_BIT)
  39
  40 extern unsigned long *phys_to_machine_mapping;
  41
  42 static inline unsigned long pfn_to_mfn(unsigned long pfn)
  43 {
  44         if (xen_feature(XENFEAT_auto_translated_physmap))
  45                 return pfn;
  46
  47         return phys_to_machine_mapping[(unsigned int)(pfn)] &
  48                 ~FOREIGN_FRAME_BIT;
  49 }
  50
  51 static inline int phys_to_machine_mapping_valid(unsigned long pfn)
  52 {
  53         if (xen_feature(XENFEAT_auto_translated_physmap))
  54                 return 1;
  55
  56         return (phys_to_machine_mapping[pfn] != INVALID_P2M_ENTRY);
  57 }
  58
  59 static inline unsigned long mfn_to_pfn(unsigned long mfn)
  60 {
  61         unsigned long pfn;
  62
  63         if (xen_feature(XENFEAT_auto_translated_physmap))
  64                 return mfn;
  65
  66 #if 0
  67         if (unlikely((mfn >> machine_to_phys_order) != 0))
  68                 return max_mapnr;
  69 #endif
  70
  71         pfn = 0;
  72         /*
  73          * The array access can fail (e.g., device space beyond end of RAM).
  74          * In such cases it doesn't matter what we return (we return garbage),
  75          * but we must handle the fault without crashing!
  76          */
  77         __get_user(pfn, &machine_to_phys_mapping[mfn]);
  78
  79         return pfn;
  80 }
  81
  82 static inline xmaddr_t phys_to_machine(xpaddr_t phys)
  83 {
  84         unsigned offset = phys.paddr & ~PAGE_MASK;
  85         return XMADDR(PFN_PHYS((u64)pfn_to_mfn(PFN_DOWN(phys.paddr))) | offset);
  86 }
  87
  88 static inline xpaddr_t machine_to_phys(xmaddr_t machine)
  89 {
  90         unsigned offset = machine.maddr & ~PAGE_MASK;
  91         return XPADDR(PFN_PHYS((u64)mfn_to_pfn(PFN_DOWN(machine.maddr))) | offset);
  92 }
  93
  94 /*
  95  * We detect special mappings in one of two ways:
  96  *  1. If the MFN is an I/O page then Xen will set the m2p entry
  97  *     to be outside our maximum possible pseudophys range.
  98  *  2. If the MFN belongs to a different domain then we will certainly
  99  *     not have MFN in our p2m table. Conversely, if the page is ours,
 100  *     then we'll have p2m(m2p(MFN))==MFN.
 101  * If we detect a special mapping then it doesn't have a 'struct page'.
 102  * We force !pfn_valid() by returning an out-of-range pointer.
 103  *
 104  * NB. These checks require that, for any MFN that is not in our reservation,
 105  * there is no PFN such that p2m(PFN) == MFN. Otherwise we can get confused if
 106  * we are foreign-mapping the MFN, and the other domain as m2p(MFN) == PFN.
 107  * Yikes! Various places must poke in INVALID_P2M_ENTRY for safety.
 108  *
 109  * NB2. When deliberately mapping foreign pages into the p2m table, you *must*
 110  *      use FOREIGN_FRAME(). This will cause pte_pfn() to choke on it, as we
 111  *      require. In all the cases we care about, the FOREIGN_FRAME bit is
 112  *      masked (e.g., pfn_to_mfn()) so behaviour there is correct.
 113  */
 114 static inline unsigned long mfn_to_local_pfn(unsigned long mfn)
 115 {
 116         extern unsigned long max_mapnr;
 117         unsigned long pfn = mfn_to_pfn(mfn);
 118         if ((pfn < max_mapnr)
 119             && !xen_feature(XENFEAT_auto_translated_physmap)
 120             && (phys_to_machine_mapping[pfn] != mfn))
 121                 return max_mapnr; /* force !pfn_valid() */
 122         return pfn;
 123 }
 124
 125 static inline void set_phys_to_machine(unsigned long pfn, unsigned long mfn)
 126 {
 127         if (xen_feature(XENFEAT_auto_translated_physmap)) {
 128                 BUG_ON(pfn != mfn && mfn != INVALID_P2M_ENTRY);
 129                 return;
 130         }
 131         phys_to_machine_mapping[pfn] = mfn;
 132 }
 133
 134 /* VIRT <-> MACHINE conversion */
 135 #define virt_to_machine(v)      (phys_to_machine(XPADDR(__pa(v))))
 136 #define virt_to_mfn(v)          (pfn_to_mfn(PFN_DOWN(__pa(v))))
 137 #define mfn_to_virt(m)          (__va(mfn_to_pfn(m) << PAGE_SHIFT))
 138
 139 #ifdef CONFIG_X86_PAE
 140 #define pte_mfn(_pte) (((_pte).pte_low >> PAGE_SHIFT) |                 \
 141                        (((_pte).pte_high & 0xfff) << (32-PAGE_SHIFT)))
 142
 143 static inline pte_t mfn_pte(unsigned long page_nr, pgprot_t pgprot)
 144 {
 145         pte_t pte;
 146
 147         pte.pte_high = (page_nr >> (32 - PAGE_SHIFT)) |
 148                 (pgprot_val(pgprot) >> 32);
 149         pte.pte_high &= (__supported_pte_mask >> 32);
 150         pte.pte_low = ((page_nr << PAGE_SHIFT) | pgprot_val(pgprot));
 151         pte.pte_low &= __supported_pte_mask;
 152
 153         return pte;
 154 }
 155
 156 static inline unsigned long long pte_val_ma(pte_t x)
 157 {
 158         return ((unsigned long long)x.pte_high << 32) | x.pte_low;
 159 }
 160 #define pmd_val_ma(v) ((v).pmd)
 161 #define pud_val_ma(v) ((v).pgd.pgd)
 162 #define __pte_ma(x)     ((pte_t) { .pte_low = (x), .pte_high = (x)>>32 } )
 163 #define __pmd_ma(x)     ((pmd_t) { (x) } )
 164 #else  /* !X86_PAE */
 165 #define pte_mfn(_pte) ((_pte).pte_low >> PAGE_SHIFT)
 166 #define mfn_pte(pfn, prot)      __pte_ma(((pfn) << PAGE_SHIFT) | pgprot_val(prot))
 167 #define pte_val_ma(x)   ((x).pte_low)
 168 #define pmd_val_ma(v)   ((v).pud.pgd.pgd)
 169 #define __pte_ma(x)     ((pte_t) { (x) } )
 170 #endif  /* CONFIG_X86_PAE */
 171
 172 #define pgd_val_ma(x)   ((x).pgd)
 173
 174
 175 xmaddr_t arbitrary_virt_to_machine(unsigned long address);
 176 void make_lowmem_page_readonly(void *vaddr);
 177 void make_lowmem_page_readwrite(void *vaddr);
 178
 179 #endif /* __XEN_PAGE_H */