x86: Let each CPU have its own GDT

headers/private/kernel/arch/x86/32/descriptors.h

@@ -9,30 +9,40 @@
 #define _KERNEL_ARCH_X86_32_DESCRIPTORS_H
 
 
-#define KERNEL_CODE_SEG	0x8
-#define KERNEL_DATA_SEG	0x10
+// Segments common for all CPUs.
+#define KERNEL_CODE_SEGMENT			1
+#define KERNEL_DATA_SEGMENT			2
 
-#define USER_CODE_SEG	0x1b
-#define USER_DATA_SEG	0x23
+#define USER_CODE_SEGMENT			3
+#define USER_DATA_SEGMENT			4
 
-#define APM_CODE32_SEGMENT	0x28
-#define APM_CODE16_SEGMENT	0x30
-#define APM_DATA_SEGMENT	0x38
+#define APM_CODE32_SEGMENT			5
+#define APM_CODE16_SEGMENT			6
+#define APM_DATA_SEGMENT			7
 
-#define BIOS_DATA_SEGMENT	0x40
+#define BIOS_DATA_SEGMENT			8
+
+// Per-CPU segments.
+#define TSS_SEGMENT					9
+#define DOUBLE_FAULT_TSS_SEGMENT	10
+#define KERNEL_TLS_SEGMENT			11
+#define USER_TLS_SEGMENT			12
+#define APM_SEGMENT					13
+
+#define GDT_SEGMENT_COUNT			14
+
+
+#define KERNEL_CODE_SELECTOR	((KERNEL_CODE_SEGMENT << 3) | DPL_KERNEL)
+#define KERNEL_DATA_SELECTOR	((KERNEL_DATA_SEGMENT << 3) | DPL_KERNEL)
+
+#define USER_CODE_SELECTOR	((USER_CODE_SEGMENT << 3) | DPL_USER)
+#define USER_DATA_SELECTOR	((USER_DATA_SEGMENT << 3) | DPL_USER)
 
 
 #ifndef _ASSEMBLER
 	// this file can also be included from assembler as well
 	// (and is in arch_interrupts.S)
 
-#define DOUBLE_FAULT_TSS_BASE_SEGMENT 9
-#define TSS_BASE_SEGMENT	(DOUBLE_FAULT_TSS_BASE_SEGMENT + smp_get_num_cpus())
-#define TLS_BASE_SEGMENT	(TSS_BASE_SEGMENT + smp_get_num_cpus())
-#define APM_BASE_SEGMENT	(TLS_BASE_SEGMENT + smp_get_num_cpus())
-
-#define TSS_SEGMENT(cpu)	(TSS_BASE_SEGMENT + cpu)
-
 // defines entries in the GDT/LDT
 
 struct segment_descriptor {
@@ -73,6 +83,9 @@ struct tss {
 	uint16 io_map_base;
 };
 
+typedef segment_descriptor global_descriptor_table[GDT_SEGMENT_COUNT];
+extern global_descriptor_table gGDTs[];
+
 
 static inline void
 clear_segment_descriptor(segment_descriptor* desc)
@@ -141,6 +154,13 @@ set_tss_descriptor(segment_descriptor* desc, addr_t base, uint32 limit)
 }
 
 
+static inline segment_descriptor*
+get_gdt(int32 cpu)
+{
+	return gGDTs[cpu];
+}
+
+
 #endif	/* _ASSEMBLER */
 
 #endif	/* _KERNEL_ARCH_X86_32_DESCRIPTORS_H */

headers/private/kernel/arch/x86/32/iframe.h

@@ -37,7 +37,7 @@ struct iframe {
 	uint32 user_ss;
 };
 
-#define IFRAME_IS_USER(f)	((f)->cs == USER_CODE_SEG \
+#define IFRAME_IS_USER(f)	((f)->cs == USER_CODE_SELECTOR \
 								|| ((f)->flags & 0x20000) != 0)
 
 

headers/private/kernel/arch/x86/64/descriptors.h

@@ -8,19 +8,28 @@
 
 // Segment definitions.
 // Note that the ordering of these is important to SYSCALL/SYSRET.
-#define KERNEL_CODE_SEG		0x08
-#define KERNEL_DATA_SEG		0x10
-#define USER_DATA_SEG		0x1b
-#define USER_CODE_SEG		0x23
+#define KERNEL_CODE_SEGMENT		1
+#define KERNEL_DATA_SEGMENT		2
+#define USER_DATA_SEGMENT		3
+#define USER_CODE_SEGMENT		4
+
+#define TSS_BASE_SEGMENT		5
+
+#define TSS_SEGMENT(cpu)		(TSS_BASE_SEGMENT + cpu * 2)
+
+#define GDT_SEGMENT_COUNT		(TSS_BASE_SEGMENT + SMP_MAX_CPUS * 2)
+
+
+#define KERNEL_CODE_SELECTOR	((KERNEL_CODE_SEGMENT << 3) | DPL_KERNEL)
+#define KERNEL_DATA_SELECTOR	((KERNEL_DATA_SEGMENT << 3) | DPL_KERNEL)
+
+#define USER_CODE_SELECTOR	((USER_CODE_SEGMENT << 3) | DPL_USER)
+#define USER_DATA_SELECTOR	((USER_DATA_SEGMENT << 3) | DPL_USER)
 
 
 #ifndef _ASSEMBLER
 
 
-#define TSS_BASE_SEGMENT	5
-#define TSS_SEGMENT(cpu)	(TSS_BASE_SEGMENT + cpu * 2)
-
-
 // Structure of a segment descriptor.
 struct segment_descriptor {
 	uint32 limit0 : 16;

headers/private/kernel/arch/x86/arch_cpu.h

@@ -335,6 +335,7 @@ typedef struct arch_cpu_info {
 	struct tss			tss;
 #ifndef __x86_64__
 	struct tss			double_fault_tss;
+	void*				kernel_tls;
 #endif
 } arch_cpu_info;
 

headers/private/kernel/arch/x86/descriptors.h

@@ -9,6 +9,10 @@
 #define _KERNEL_ARCH_x86_DESCRIPTORS_H
 
 
+#define DPL_KERNEL	0
+#define DPL_USER	3
+
+
 #ifndef _ASSEMBLER
 
 
@@ -18,11 +22,6 @@
 struct kernel_args;
 
 
-enum descriptor_privilege_levels {
-	DPL_KERNEL = 0,
-	DPL_USER = 3,
-};
-
 enum descriptor_types {
 	// segment types
 	DT_CODE_EXECUTE_ONLY = 0x8,
@@ -48,6 +47,7 @@ enum gate_types {
 };
 
 
+void x86_descriptors_preboot_init_percpu(kernel_args* args, int cpu);
 void x86_descriptors_init(kernel_args* args);
 void x86_descriptors_init_percpu(kernel_args* args, int cpu);
 status_t x86_descriptors_init_post_vm(kernel_args* args);