arch/x86/include/asm/fixmap.h

   1 /*
   2  * fixmap.h: compile-time virtual memory allocation
   3  *
   4  * This file is subject to the terms and conditions of the GNU General Public
   5  * License.  See the file "COPYING" in the main directory of this archive
   6  * for more details.
   7  *
   8  * Copyright (C) 1998 Ingo Molnar
   9  *
  10  * Support of BIGMEM added by Gerhard Wichert, Siemens AG, July 1999
  11  * x86_32 and x86_64 integration by Gustavo F. Padovan, February 2009
  12  */
  13
  14 #ifndef _ASM_X86_FIXMAP_H
  15 #define _ASM_X86_FIXMAP_H
  16
  17 #ifndef __ASSEMBLY__
  18 #include <linux/kernel.h>
  19 #include <asm/acpi.h>
  20 #include <asm/apicdef.h>
  21 #include <asm/page.h>
  22 #ifdef CONFIG_X86_32
  23 #include <linux/threads.h>
  24 #include <asm/kmap_types.h>
  25 #else
  26 #include <uapi/asm/vsyscall.h>
  27 #endif
  28
  29 /*
  30  * We can't declare FIXADDR_TOP as variable for x86_64 because vsyscall
  31  * uses fixmaps that relies on FIXADDR_TOP for proper address calculation.
  32  * Because of this, FIXADDR_TOP x86 integration was left as later work.
  33  */
  34 #ifdef CONFIG_X86_32
  35 /* used by vmalloc.c, vsyscall.lds.S.
  36  *
  37  * Leave one empty page between vmalloc'ed areas and
  38  * the start of the fixmap.
  39  */
  40 extern unsigned long __FIXADDR_TOP;
  41 #define FIXADDR_TOP     ((unsigned long)__FIXADDR_TOP)
  42 #else
  43 #define FIXADDR_TOP     (round_up(VSYSCALL_ADDR + PAGE_SIZE, 1<<PMD_SHIFT) - \
  44                          PAGE_SIZE)
  45 #endif
  46
  47 /*
  48  * cpu_entry_area is a percpu region in the fixmap that contains things
  49  * needed by the CPU and early entry/exit code.  Real types aren't used
  50  * for all fields here to avoid circular header dependencies.
  51  *
  52  * Every field is a virtual alias of some other allocated backing store.
  53  * There is no direct allocation of a struct cpu_entry_area.
  54  */
  55 struct cpu_entry_area {
  56         char gdt[PAGE_SIZE];
  57
  58         /*
  59          * The GDT is just below cpu_tss and thus serves (on x86_64) as a
  60          * a read-only guard page for the SYSENTER stack at the bottom
  61          * of the TSS region.
  62          */
  63         struct tss_struct tss;
  64
  65         char entry_trampoline[PAGE_SIZE];
  66
  67 #ifdef CONFIG_X86_64
  68         /*
  69          * Exception stacks used for IST entries.
  70          *
  71          * In the future, this should have a separate slot for each stack
  72          * with guard pages between them.
  73          */
  74         char exception_stacks[(N_EXCEPTION_STACKS - 1) * EXCEPTION_STKSZ + DEBUG_STKSZ];
  75 #endif
  76 };
  77
  78 #define CPU_ENTRY_AREA_PAGES (sizeof(struct cpu_entry_area) / PAGE_SIZE)
  79
  80 extern void setup_cpu_entry_areas(void);
  81
  82 /*
  83  * Here we define all the compile-time 'special' virtual
  84  * addresses. The point is to have a constant address at
  85  * compile time, but to set the physical address only
  86  * in the boot process.
  87  * for x86_32: We allocate these special addresses
  88  * from the end of virtual memory (0xfffff000) backwards.
  89  * Also this lets us do fail-safe vmalloc(), we
  90  * can guarantee that these special addresses and
  91  * vmalloc()-ed addresses never overlap.
  92  *
  93  * These 'compile-time allocated' memory buffers are
  94  * fixed-size 4k pages (or larger if used with an increment
  95  * higher than 1). Use set_fixmap(idx,phys) to associate
  96  * physical memory with fixmap indices.
  97  *
  98  * TLB entries of such buffers will not be flushed across
  99  * task switches.
 100  */
 101 enum fixed_addresses {
 102 #ifdef CONFIG_X86_32
 103         FIX_HOLE,
 104 #else
 105 #ifdef CONFIG_X86_VSYSCALL_EMULATION
 106         VSYSCALL_PAGE = (FIXADDR_TOP - VSYSCALL_ADDR) >> PAGE_SHIFT,
 107 #endif
 108 #endif
 109         FIX_DBGP_BASE,
 110         FIX_EARLYCON_MEM_BASE,
 111 #ifdef CONFIG_PROVIDE_OHCI1394_DMA_INIT
 112         FIX_OHCI1394_BASE,
 113 #endif
 114 #ifdef CONFIG_X86_LOCAL_APIC
 115         FIX_APIC_BASE,  /* local (CPU) APIC) -- required for SMP or not */
 116 #endif
 117 #ifdef CONFIG_X86_IO_APIC
 118         FIX_IO_APIC_BASE_0,
 119         FIX_IO_APIC_BASE_END = FIX_IO_APIC_BASE_0 + MAX_IO_APICS - 1,
 120 #endif
 121         FIX_RO_IDT,     /* Virtual mapping for read-only IDT */
 122 #ifdef CONFIG_X86_32
 123         FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */
 124         FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
 125 #ifdef CONFIG_PCI_MMCONFIG
 126         FIX_PCIE_MCFG,
 127 #endif
 128 #endif
 129 #ifdef CONFIG_PARAVIRT
 130         FIX_PARAVIRT_BOOTMAP,
 131 #endif
 132         FIX_TEXT_POKE1, /* reserve 2 pages for text_poke() */
 133         FIX_TEXT_POKE0, /* first page is last, because allocation is backward */
 134 #ifdef  CONFIG_X86_INTEL_MID
 135         FIX_LNW_VRTC,
 136 #endif
 137         /* Fixmap entries to remap the GDTs, one per processor. */
 138         FIX_CPU_ENTRY_AREA_TOP,
 139         FIX_CPU_ENTRY_AREA_BOTTOM = FIX_CPU_ENTRY_AREA_TOP + (CPU_ENTRY_AREA_PAGES * NR_CPUS) - 1,
 140
 141 #ifdef CONFIG_ACPI_APEI_GHES
 142         /* Used for GHES mapping from assorted contexts */
 143         FIX_APEI_GHES_IRQ,
 144         FIX_APEI_GHES_NMI,
 145 #endif
 146
 147         __end_of_permanent_fixed_addresses,
 148
 149         /*
 150          * 512 temporary boot-time mappings, used by early_ioremap(),
 151          * before ioremap() is functional.
 152          *
 153          * If necessary we round it up to the next 512 pages boundary so
 154          * that we can have a single pgd entry and a single pte table:
 155          */
 156 #define NR_FIX_BTMAPS           64
 157 #define FIX_BTMAPS_SLOTS        8
 158 #define TOTAL_FIX_BTMAPS        (NR_FIX_BTMAPS * FIX_BTMAPS_SLOTS)
 159         FIX_BTMAP_END =
 160          (__end_of_permanent_fixed_addresses ^
 161           (__end_of_permanent_fixed_addresses + TOTAL_FIX_BTMAPS - 1)) &
 162          -PTRS_PER_PTE
 163          ? __end_of_permanent_fixed_addresses + TOTAL_FIX_BTMAPS -
 164            (__end_of_permanent_fixed_addresses & (TOTAL_FIX_BTMAPS - 1))
 165          : __end_of_permanent_fixed_addresses,
 166         FIX_BTMAP_BEGIN = FIX_BTMAP_END + TOTAL_FIX_BTMAPS - 1,
 167 #ifdef CONFIG_X86_32
 168         FIX_WP_TEST,
 169 #endif
 170 #ifdef CONFIG_INTEL_TXT
 171         FIX_TBOOT_BASE,
 172 #endif
 173         __end_of_fixed_addresses
 174 };
 175
 176
 177 extern void reserve_top_address(unsigned long reserve);
 178
 179 #define FIXADDR_SIZE    (__end_of_permanent_fixed_addresses << PAGE_SHIFT)
 180 #define FIXADDR_START           (FIXADDR_TOP - FIXADDR_SIZE)
 181
 182 extern int fixmaps_set;
 183
 184 extern pte_t *kmap_pte;
 185 #define kmap_prot PAGE_KERNEL
 186 extern pte_t *pkmap_page_table;
 187
 188 void __native_set_fixmap(enum fixed_addresses idx, pte_t pte);
 189 void native_set_fixmap(enum fixed_addresses idx,
 190                        phys_addr_t phys, pgprot_t flags);
 191
 192 #ifndef CONFIG_PARAVIRT
 193 static inline void __set_fixmap(enum fixed_addresses idx,
 194                                 phys_addr_t phys, pgprot_t flags)
 195 {
 196         native_set_fixmap(idx, phys, flags);
 197 }
 198 #endif
 199
 200 #include <asm-generic/fixmap.h>
 201
 202 #define __late_set_fixmap(idx, phys, flags) __set_fixmap(idx, phys, flags)
 203 #define __late_clear_fixmap(idx) __set_fixmap(idx, 0, __pgprot(0))
 204
 205 void __early_set_fixmap(enum fixed_addresses idx,
 206                         phys_addr_t phys, pgprot_t flags);
 207
 208 static inline unsigned int __get_cpu_entry_area_page_index(int cpu, int page)
 209 {
 210         BUILD_BUG_ON(sizeof(struct cpu_entry_area) % PAGE_SIZE != 0);
 211
 212         return FIX_CPU_ENTRY_AREA_BOTTOM - cpu*CPU_ENTRY_AREA_PAGES - page;
 213 }
 214
 215 #define __get_cpu_entry_area_offset_index(cpu, offset) ({               \
 216         BUILD_BUG_ON(offset % PAGE_SIZE != 0);                          \
 217         __get_cpu_entry_area_page_index(cpu, offset / PAGE_SIZE);       \
 218         })
 219
 220 #define get_cpu_entry_area_index(cpu, field)                            \
 221         __get_cpu_entry_area_offset_index((cpu), offsetof(struct cpu_entry_area, field))
 222
 223 static inline struct cpu_entry_area *get_cpu_entry_area(int cpu)
 224 {
 225         return (struct cpu_entry_area *)__fix_to_virt(__get_cpu_entry_area_page_index(cpu, 0));
 226 }
 227
 228 static inline struct SYSENTER_stack *cpu_SYSENTER_stack(int cpu)
 229 {
 230         return &get_cpu_entry_area(cpu)->tss.SYSENTER_stack;
 231 }
 232
 233 #endif /* !__ASSEMBLY__ */
 234 #endif /* _ASM_X86_FIXMAP_H */