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// SPDX-License-Identifier: GPL-2.0
#ifndef _ASM_X86_CPU_ENTRY_AREA_H
#define _ASM_X86_CPU_ENTRY_AREA_H
#include <linux/percpu-defs.h>
#include <asm/processor.h>
/*
* cpu_entry_area is a percpu region that contains things needed by the CPU
* and early entry/exit code. Real types aren't used for all fields here
* to avoid circular header dependencies.
*
* Every field is a virtual alias of some other allocated backing store.
* There is no direct allocation of a struct cpu_entry_area.
*/
struct cpu_entry_area {
char gdt[PAGE_SIZE];
/*
* The GDT is just below entry_stack and thus serves (on x86_64) as
* a a read-only guard page.
*/
struct entry_stack_page entry_stack_page;
/*
* On x86_64, the TSS is mapped RO. On x86_32, it's mapped RW because
* we need task switches to work, and task switches write to the TSS.
*/
struct tss_struct tss;
char entry_trampoline[PAGE_SIZE];
#ifdef CONFIG_X86_64
/*
* Exception stacks used for IST entries.
*
* In the future, this should have a separate slot for each stack
* with guard pages between them.
*/
char exception_stacks[(N_EXCEPTION_STACKS - 1) * EXCEPTION_STKSZ + DEBUG_STKSZ];
#endif
};
#define CPU_ENTRY_AREA_SIZE (sizeof(struct cpu_entry_area))
#define CPU_ENTRY_AREA_PAGES (CPU_ENTRY_AREA_SIZE / PAGE_SIZE)
DECLARE_PER_CPU(struct cpu_entry_area *, cpu_entry_area);
extern void setup_cpu_entry_areas(void);
#endif
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