cet.h

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/*
 * Copyright (c) 2025 Intel Corporation
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 */
 
#ifndef ZEPHYR_INCLUDE_ARCH_X86_CET_H_
#define ZEPHYR_INCLUDE_ARCH_X86_CET_H_
 
#ifndef _ASMLANGUAGE
 
#ifdef CONFIG_HW_SHADOW_STACK
 
extern FUNC_NORETURN void z_thread_entry(k_thread_entry_t entry,
                                         void *p1, void *p2, void *p3);
 
typedef uintptr_t arch_thread_hw_shadow_stack_t;
 
#define ARCH_THREAD_HW_SHADOW_STACK_SIZE(size_) \
        MAX(ROUND_UP((CONFIG_HW_SHADOW_STACK_PERCENTAGE_SIZE * (size_) / 100), \
                      CONFIG_X86_CET_SHADOW_STACK_ALIGNMENT), \
            CONFIG_HW_SHADOW_STACK_MIN_SIZE)
 
#define ARCH_THREAD_HW_SHADOW_STACK_DECLARE(sym, size) \
        extern arch_thread_hw_shadow_stack_t sym[size / sizeof(arch_thread_hw_shadow_stack_t)]
 
#define ARCH_THREAD_HW_SHADOW_STACK_ARRAY_DECLARE(sym, nmemb, size) \
        extern arch_thread_hw_shadow_stack_t \
                sym[nmemb][size / sizeof(arch_thread_hw_shadow_stack_t)]
 
#define ARCH_THREAD_HW_SHADOW_STACK_ARRAY_DEFINE(name, nmemb, size) \
        arch_thread_hw_shadow_stack_t Z_GENERIC_SECTION(.x86shadowstack.arr_ ##name) \
        __aligned(CONFIG_X86_CET_SHADOW_STACK_ALIGNMENT) \
        name[MAX(nmemb, 1)][size / sizeof(arch_thread_hw_shadow_stack_t)] = \
                { \
                        [0][0] = nmemb, \
                }
 
#ifdef CONFIG_X86_64
#define ARCH_THREAD_HW_SHADOW_STACK_DEFINE(name, size) \
        arch_thread_hw_shadow_stack_t Z_GENERIC_SECTION(.x86shadowstack) \
        __aligned(CONFIG_X86_CET_SHADOW_STACK_ALIGNMENT) \
        name[size / sizeof(arch_thread_hw_shadow_stack_t)] = \
                { [size / sizeof(arch_thread_hw_shadow_stack_t) - 5] = \
                   (uintptr_t)name + size - 4 * sizeof(arch_thread_hw_shadow_stack_t) + 1, \
                  [size / sizeof(arch_thread_hw_shadow_stack_t) - 4] = \
                  (uintptr_t)name + size - 1 * sizeof(arch_thread_hw_shadow_stack_t), \
                  [size / sizeof(arch_thread_hw_shadow_stack_t) - 3] = \
                   (uintptr_t)z_thread_entry, \
                  [size / sizeof(arch_thread_hw_shadow_stack_t) - 2] = \
                   (uintptr_t)X86_KERNEL_CS }
 
#else /* CONFIG_X86_64 */
 
#ifdef CONFIG_X86_DEBUG_INFO
extern void z_x86_thread_entry_wrapper(k_thread_entry_t entry,
                                      void *p1, void *p2, void *p3);
#define ___x86_entry_point z_x86_thread_entry_wrapper
#else
#define ___x86_entry_point z_thread_entry
#endif
 
#define ARCH_THREAD_HW_SHADOW_STACK_DEFINE(name, size) \
        arch_thread_hw_shadow_stack_t Z_GENERIC_SECTION(.x86shadowstack) \
        __aligned(CONFIG_X86_CET_SHADOW_STACK_ALIGNMENT) \
        name[size / sizeof(arch_thread_hw_shadow_stack_t)] = \
                { [size / sizeof(arch_thread_hw_shadow_stack_t) - 4] = \
                   (uintptr_t)name + size - 2 * sizeof(arch_thread_hw_shadow_stack_t), \
                  [size / sizeof(arch_thread_hw_shadow_stack_t) - 3] = 0, \
                  [size / sizeof(arch_thread_hw_shadow_stack_t) - 2] = \
                   (uintptr_t)___x86_entry_point, \
                }
#endif /* CONFIG_X86_64 */
 
int arch_thread_hw_shadow_stack_attach(struct k_thread *thread,
                                       arch_thread_hw_shadow_stack_t *stack,
                                       size_t stack_size);
 
#endif /* CONFIG_HW_SHADOW_STACK */
 
#endif /* _ASMLANGUAGE */
#endif /* ZEPHYR_INCLUDE_ARCH_X86_CET_H_ */