diff options
Diffstat (limited to 'arch/x86/include/uapi/asm/ldt.h')
| -rw-r--r-- | arch/x86/include/uapi/asm/ldt.h | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/arch/x86/include/uapi/asm/ldt.h b/arch/x86/include/uapi/asm/ldt.h new file mode 100644 index 000000000..d62ac5db0 --- /dev/null +++ b/arch/x86/include/uapi/asm/ldt.h @@ -0,0 +1,48 @@ +/* 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 */ |