| /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ | |
| /* | |
| * ldt.h | |
| * | |
| * Definitions of structures used with the modify_ldt system call. | |
| */ | |
| #ifndef _ASM_X86_LDT_H | |
| #define _ASM_X86_LDT_H | |
| /* Maximum number of LDT entries supported. */ | |
| #define LDT_ENTRIES 8192 | |
| /* The size of each LDT entry. */ | |
| #define LDT_ENTRY_SIZE 8 | |
| #ifndef __ASSEMBLY__ | |
| /* | |
| * Note on 64bit base and limit is ignored and you cannot set DS/ES/CS | |
| * not to the default values if you still want to do syscalls. This | |
| * call is more for 32bit mode therefore. | |
| */ | |
| struct user_desc { | |
| unsigned int entry_number; | |
| unsigned int base_addr; | |
| unsigned int limit; | |
| unsigned int seg_32bit:1; | |
| unsigned int contents:2; | |
| unsigned int read_exec_only:1; | |
| unsigned int limit_in_pages:1; | |
| unsigned int seg_not_present:1; | |
| unsigned int useable:1; | |
| #ifdef __x86_64__ | |
| /* | |
| * Because this bit is not present in 32-bit user code, user | |
| * programs can pass uninitialized values here. Therefore, in | |
| * any context in which a user_desc comes from a 32-bit program, | |
| * the kernel must act as though lm == 0, regardless of the | |
| * actual value. | |
| */ | |
| unsigned int lm:1; | |
| #endif | |
| }; | |
| #define MODIFY_LDT_CONTENTS_DATA 0 | |
| #define MODIFY_LDT_CONTENTS_STACK 1 | |
| #define MODIFY_LDT_CONTENTS_CODE 2 | |
| #endif /* !__ASSEMBLY__ */ | |
| #endif /* _ASM_X86_LDT_H */ |