arch/x86/include/asm/cpu_entry_area.h

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #ifndef _ASM_X86_CPU_ENTRY_AREA_H
   4 #define _ASM_X86_CPU_ENTRY_AREA_H
   5
   6 #include <linux/percpu-defs.h>
   7 #include <asm/processor.h>
   8
   9 /*
  10  * cpu_entry_area is a percpu region that contains things needed by the CPU
  11  * and early entry/exit code.  Real types aren't used for all fields here
  12  * to avoid circular header dependencies.
  13  *
  14  * Every field is a virtual alias of some other allocated backing store.
  15  * There is no direct allocation of a struct cpu_entry_area.
  16  */
  17 struct cpu_entry_area {
  18         char gdt[PAGE_SIZE];
  19
  20         /*
  21          * The GDT is just below entry_stack and thus serves (on x86_64) as
  22          * a a read-only guard page.
  23          */
  24         struct entry_stack_page entry_stack_page;
  25
  26         /*
  27          * On x86_64, the TSS is mapped RO.  On x86_32, it's mapped RW because
  28          * we need task switches to work, and task switches write to the TSS.
  29          */
  30         struct tss_struct tss;
  31
  32         char entry_trampoline[PAGE_SIZE];
  33
  34 #ifdef CONFIG_X86_64
  35         /*
  36          * Exception stacks used for IST entries.
  37          *
  38          * In the future, this should have a separate slot for each stack
  39          * with guard pages between them.
  40          */
  41         char exception_stacks[(N_EXCEPTION_STACKS - 1) * EXCEPTION_STKSZ + DEBUG_STKSZ];
  42 #endif
  43 };
  44
  45 #define CPU_ENTRY_AREA_SIZE     (sizeof(struct cpu_entry_area))
  46 #define CPU_ENTRY_AREA_TOT_SIZE (CPU_ENTRY_AREA_SIZE * NR_CPUS)
  47
  48 DECLARE_PER_CPU(struct cpu_entry_area *, cpu_entry_area);
  49
  50 extern void setup_cpu_entry_areas(void);
  51 extern void cea_set_pte(void *cea_vaddr, phys_addr_t pa, pgprot_t flags);
  52
  53 #define CPU_ENTRY_AREA_RO_IDT           CPU_ENTRY_AREA_BASE
  54 #define CPU_ENTRY_AREA_PER_CPU          (CPU_ENTRY_AREA_RO_IDT + PAGE_SIZE)
  55
  56 #define CPU_ENTRY_AREA_RO_IDT_VADDR     ((void *)CPU_ENTRY_AREA_RO_IDT)
  57
  58 #define CPU_ENTRY_AREA_MAP_SIZE                 \
  59         (CPU_ENTRY_AREA_PER_CPU + CPU_ENTRY_AREA_TOT_SIZE - CPU_ENTRY_AREA_BASE)
  60
  61 extern struct cpu_entry_area *get_cpu_entry_area(int cpu);
  62
  63 static inline struct entry_stack *cpu_entry_stack(int cpu)
  64 {
  65         return &get_cpu_entry_area(cpu)->entry_stack_page.stack;
  66 }
  67
  68 #endif