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 #define CPU_ENTRY_AREA_PAGES (sizeof(struct cpu_entry_area) / PAGE_SIZE)
  60
  61 /*
  62  * Here we define all the compile-time 'special' virtual
  63  * addresses. The point is to have a constant address at
  64  * compile time, but to set the physical address only
  65  * in the boot process.
  66  * for x86_32: We allocate these special addresses
  67  * from the end of virtual memory (0xfffff000) backwards.
  68  * Also this lets us do fail-safe vmalloc(), we
  69  * can guarantee that these special addresses and
  70  * vmalloc()-ed addresses never overlap.
  71  *
  72  * These 'compile-time allocated' memory buffers are
  73  * fixed-size 4k pages (or larger if used with an increment
  74  * higher than 1). Use set_fixmap(idx,phys) to associate
  75  * physical memory with fixmap indices.
  76  *
  77  * TLB entries of such buffers will not be flushed across
  78  * task switches.
  79  */
  80 enum fixed_addresses {
  81 #ifdef CONFIG_X86_32
  82         FIX_HOLE,
  83 #else
  84 #ifdef CONFIG_X86_VSYSCALL_EMULATION
  85         VSYSCALL_PAGE = (FIXADDR_TOP - VSYSCALL_ADDR) >> PAGE_SHIFT,
  86 #endif
  87 #endif
  88         FIX_DBGP_BASE,
  89         FIX_EARLYCON_MEM_BASE,
  90 #ifdef CONFIG_PROVIDE_OHCI1394_DMA_INIT
  91         FIX_OHCI1394_BASE,
  92 #endif
  93 #ifdef CONFIG_X86_LOCAL_APIC
  94         FIX_APIC_BASE,  /* local (CPU) APIC) -- required for SMP or not */
  95 #endif
  96 #ifdef CONFIG_X86_IO_APIC
  97         FIX_IO_APIC_BASE_0,
  98         FIX_IO_APIC_BASE_END = FIX_IO_APIC_BASE_0 + MAX_IO_APICS - 1,
  99 #endif
 100         FIX_RO_IDT,     /* Virtual mapping for read-only IDT */
 101 #ifdef CONFIG_X86_32
 102         FIX_KMAP_BEGIN, /* reserved pte's for temporary kernel mappings */
 103         FIX_KMAP_END = FIX_KMAP_BEGIN+(KM_TYPE_NR*NR_CPUS)-1,
 104 #ifdef CONFIG_PCI_MMCONFIG
 105         FIX_PCIE_MCFG,
 106 #endif
 107 #endif
 108 #ifdef CONFIG_PARAVIRT
 109         FIX_PARAVIRT_BOOTMAP,
 110 #endif
 111         FIX_TEXT_POKE1, /* reserve 2 pages for text_poke() */
 112         FIX_TEXT_POKE0, /* first page is last, because allocation is backward */
 113 #ifdef  CONFIG_X86_INTEL_MID
 114         FIX_LNW_VRTC,
 115 #endif
 116         /* Fixmap entries to remap the GDTs, one per processor. */
 117         FIX_CPU_ENTRY_AREA_TOP,
 118         FIX_CPU_ENTRY_AREA_BOTTOM = FIX_CPU_ENTRY_AREA_TOP + (CPU_ENTRY_AREA_PAGES * NR_CPUS) - 1,
 119
 120 #ifdef CONFIG_ACPI_APEI_GHES
 121         /* Used for GHES mapping from assorted contexts */
 122         FIX_APEI_GHES_IRQ,
 123         FIX_APEI_GHES_NMI,
 124 #endif
 125
 126         __end_of_permanent_fixed_addresses,
 127
 128         /*
 129          * 512 temporary boot-time mappings, used by early_ioremap(),
 130          * before ioremap() is functional.
 131          *
 132          * If necessary we round it up to the next 512 pages boundary so
 133          * that we can have a single pgd entry and a single pte table:
 134          */
 135 #define NR_FIX_BTMAPS           64
 136 #define FIX_BTMAPS_SLOTS        8
 137 #define TOTAL_FIX_BTMAPS        (NR_FIX_BTMAPS * FIX_BTMAPS_SLOTS)
 138         FIX_BTMAP_END =
 139          (__end_of_permanent_fixed_addresses ^
 140           (__end_of_permanent_fixed_addresses + TOTAL_FIX_BTMAPS - 1)) &
 141          -PTRS_PER_PTE
 142          ? __end_of_permanent_fixed_addresses + TOTAL_FIX_BTMAPS -
 143            (__end_of_permanent_fixed_addresses & (TOTAL_FIX_BTMAPS - 1))
 144          : __end_of_permanent_fixed_addresses,
 145         FIX_BTMAP_BEGIN = FIX_BTMAP_END + TOTAL_FIX_BTMAPS - 1,
 146 #ifdef CONFIG_X86_32
 147         FIX_WP_TEST,
 148 #endif
 149 #ifdef CONFIG_INTEL_TXT
 150         FIX_TBOOT_BASE,
 151 #endif
 152         __end_of_fixed_addresses
 153 };
 154
 155
 156 extern void reserve_top_address(unsigned long reserve);
 157
 158 #define FIXADDR_SIZE    (__end_of_permanent_fixed_addresses << PAGE_SHIFT)
 159 #define FIXADDR_START           (FIXADDR_TOP - FIXADDR_SIZE)
 160
 161 extern int fixmaps_set;
 162
 163 extern pte_t *kmap_pte;
 164 #define kmap_prot PAGE_KERNEL
 165 extern pte_t *pkmap_page_table;
 166
 167 void __native_set_fixmap(enum fixed_addresses idx, pte_t pte);
 168 void native_set_fixmap(enum fixed_addresses idx,
 169                        phys_addr_t phys, pgprot_t flags);
 170
 171 #ifndef CONFIG_PARAVIRT
 172 static inline void __set_fixmap(enum fixed_addresses idx,
 173                                 phys_addr_t phys, pgprot_t flags)
 174 {
 175         native_set_fixmap(idx, phys, flags);
 176 }
 177 #endif
 178
 179 #include <asm-generic/fixmap.h>
 180
 181 #define __late_set_fixmap(idx, phys, flags) __set_fixmap(idx, phys, flags)
 182 #define __late_clear_fixmap(idx) __set_fixmap(idx, 0, __pgprot(0))
 183
 184 void __early_set_fixmap(enum fixed_addresses idx,
 185                         phys_addr_t phys, pgprot_t flags);
 186
 187 static inline unsigned int __get_cpu_entry_area_page_index(int cpu, int page)
 188 {
 189         BUILD_BUG_ON(sizeof(struct cpu_entry_area) % PAGE_SIZE != 0);
 190
 191         return FIX_CPU_ENTRY_AREA_BOTTOM - cpu*CPU_ENTRY_AREA_PAGES - page;
 192 }
 193
 194 #define __get_cpu_entry_area_offset_index(cpu, offset) ({               \
 195         BUILD_BUG_ON(offset % PAGE_SIZE != 0);                          \
 196         __get_cpu_entry_area_page_index(cpu, offset / PAGE_SIZE);       \
 197         })
 198
 199 #define get_cpu_entry_area_index(cpu, field)                            \
 200         __get_cpu_entry_area_offset_index((cpu), offsetof(struct cpu_entry_area, field))
 201
 202 static inline struct cpu_entry_area *get_cpu_entry_area(int cpu)
 203 {
 204         return (struct cpu_entry_area *)__fix_to_virt(__get_cpu_entry_area_page_index(cpu, 0));
 205 }
 206
 207 #endif /* !__ASSEMBLY__ */
 208 #endif /* _ASM_X86_FIXMAP_H */