Add build system scaffolding and libc headers

1 files changed, 48 insertions, 0 deletions

diff --git a/include/arch/x86_64/asm/ldt.h b/include/arch/x86_64/asm/ldt.h
new file mode 100644
index 00000000..259c6f0b
--- /dev/null
+++ b/include/arch/x86_64/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 __ASSEMBLER__
+/*
+ * 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 /* !__ASSEMBLER__ */
+#endif /* _ASM_X86_LDT_H */