| 1 | /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */ |
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| 2 | /* |
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| 3 | * ldt.h |
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| 4 | * |
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| 5 | * Definitions of structures used with the modify_ldt system call. |
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| 6 | */ |
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| 7 | #ifndef _ASM_X86_LDT_H |
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| 8 | #define _ASM_X86_LDT_H |
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| 9 | |
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| 10 | /* Maximum number of LDT entries supported. */ |
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| 11 | #define LDT_ENTRIES 8192 |
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| 12 | /* The size of each LDT entry. */ |
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| 13 | #define LDT_ENTRY_SIZE 8 |
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| 14 | |
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| 15 | #ifndef __ASSEMBLY__ |
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| 16 | /* |
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| 17 | * Note on 64bit base and limit is ignored and you cannot set DS/ES/CS |
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| 18 | * not to the default values if you still want to do syscalls. This |
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| 19 | * call is more for 32bit mode therefore. |
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| 20 | */ |
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| 21 | struct user_desc { |
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| 22 | unsigned int entry_number; |
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| 23 | unsigned int base_addr; |
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| 24 | unsigned int limit; |
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| 25 | unsigned int seg_32bit:1; |
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| 26 | unsigned int contents:2; |
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| 27 | unsigned int read_exec_only:1; |
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| 28 | unsigned int limit_in_pages:1; |
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| 29 | unsigned int seg_not_present:1; |
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| 30 | unsigned int useable:1; |
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| 31 | #ifdef __x86_64__ |
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| 32 | /* |
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| 33 | * Because this bit is not present in 32-bit user code, user |
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| 34 | * programs can pass uninitialized values here. Therefore, in |
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| 35 | * any context in which a user_desc comes from a 32-bit program, |
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| 36 | * the kernel must act as though lm == 0, regardless of the |
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| 37 | * actual value. |
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| 38 | */ |
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| 39 | unsigned int lm:1; |
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| 40 | #endif |
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| 41 | }; |
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| 42 | |
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| 43 | #define MODIFY_LDT_CONTENTS_DATA 0 |
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| 44 | #define MODIFY_LDT_CONTENTS_STACK 1 |
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| 45 | #define MODIFY_LDT_CONTENTS_CODE 2 |
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| 46 | |
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| 47 | #endif /* !__ASSEMBLY__ */ |
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| 48 | #endif /* _ASM_X86_LDT_H */ |
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| 49 | |
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