summaryrefslogtreecommitdiffstats
path: root/include/asm-i386/segment.h
diff options
context:
space:
mode:
Diffstat (limited to 'include/asm-i386/segment.h')
-rw-r--r--include/asm-i386/segment.h101
1 files changed, 101 insertions, 0 deletions
diff --git a/include/asm-i386/segment.h b/include/asm-i386/segment.h
new file mode 100644
index 0000000..bb5ff5b
--- /dev/null
+++ b/include/asm-i386/segment.h
@@ -0,0 +1,101 @@
+#ifndef _ASM_SEGMENT_H
+#define _ASM_SEGMENT_H
+
+/*
+ * The layout of the per-CPU GDT under Linux:
+ *
+ * 0 - null
+ * 1 - reserved
+ * 2 - reserved
+ * 3 - reserved
+ *
+ * 4 - unused <==== new cacheline
+ * 5 - unused
+ *
+ * ------- start of TLS (Thread-Local Storage) segments:
+ *
+ * 6 - TLS segment #1 [ glibc's TLS segment ]
+ * 7 - TLS segment #2 [ Wine's %fs Win32 segment ]
+ * 8 - TLS segment #3
+ * 9 - reserved
+ * 10 - reserved
+ * 11 - reserved
+ *
+ * ------- start of kernel segments:
+ *
+ * 12 - kernel code segment <==== new cacheline
+ * 13 - kernel data segment
+ * 14 - default user CS
+ * 15 - default user DS
+ * 16 - TSS
+ * 17 - LDT
+ * 18 - PNPBIOS support (16->32 gate)
+ * 19 - PNPBIOS support
+ * 20 - PNPBIOS support
+ * 21 - PNPBIOS support
+ * 22 - PNPBIOS support
+ * 23 - APM BIOS support
+ * 24 - APM BIOS support
+ * 25 - APM BIOS support
+ *
+ * 26 - ESPFIX small SS
+ * 27 - unused
+ * 28 - unused
+ * 29 - unused
+ * 30 - unused
+ * 31 - TSS for double fault handler
+ */
+#define GDT_ENTRY_TLS_ENTRIES 3
+#define GDT_ENTRY_TLS_MIN 6
+#define GDT_ENTRY_TLS_MAX (GDT_ENTRY_TLS_MIN + GDT_ENTRY_TLS_ENTRIES - 1)
+
+#define TLS_SIZE (GDT_ENTRY_TLS_ENTRIES * 8)
+
+#define GDT_ENTRY_DEFAULT_USER_CS 14
+#define __USER_CS (GDT_ENTRY_DEFAULT_USER_CS * 8 + 3)
+
+#define GDT_ENTRY_DEFAULT_USER_DS 15
+#define __USER_DS (GDT_ENTRY_DEFAULT_USER_DS * 8 + 3)
+
+#define GDT_ENTRY_KERNEL_BASE 12
+
+#define GDT_ENTRY_KERNEL_CS (GDT_ENTRY_KERNEL_BASE + 0)
+#define __KERNEL_CS (GDT_ENTRY_KERNEL_CS * 8)
+
+#define GDT_ENTRY_KERNEL_DS (GDT_ENTRY_KERNEL_BASE + 1)
+#define __KERNEL_DS (GDT_ENTRY_KERNEL_DS * 8)
+
+#define GDT_ENTRY_TSS (GDT_ENTRY_KERNEL_BASE + 4)
+#define GDT_ENTRY_LDT (GDT_ENTRY_KERNEL_BASE + 5)
+
+#define GDT_ENTRY_PNPBIOS_BASE (GDT_ENTRY_KERNEL_BASE + 6)
+#define GDT_ENTRY_APMBIOS_BASE (GDT_ENTRY_KERNEL_BASE + 11)
+
+#define GDT_ENTRY_ESPFIX_SS (GDT_ENTRY_KERNEL_BASE + 14)
+#define __ESPFIX_SS (GDT_ENTRY_ESPFIX_SS * 8)
+
+#define GDT_ENTRY_DOUBLEFAULT_TSS 31
+
+/*
+ * The GDT has 32 entries
+ */
+#define GDT_ENTRIES 32
+
+#define GDT_SIZE (GDT_ENTRIES * 8)
+
+/* Simple and small GDT entries for booting only */
+
+#define GDT_ENTRY_BOOT_CS 2
+#define __BOOT_CS (GDT_ENTRY_BOOT_CS * 8)
+
+#define GDT_ENTRY_BOOT_DS (GDT_ENTRY_BOOT_CS + 1)
+#define __BOOT_DS (GDT_ENTRY_BOOT_DS * 8)
+
+/*
+ * The interrupt descriptor table has room for 256 idt's,
+ * the global descriptor table is dependent on the number
+ * of tasks we can have..
+ */
+#define IDT_ENTRIES 256
+
+#endif
OpenPOWER on IntegriCloud