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-rw-r--r--arch/x86/include/uapi/asm/ldt.h48
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 */