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 69