add LAPIC support of the 64bit kernel

arch/x86/include/asm/processor.h

@@ -151,7 +151,7 @@ inline static void wmb(void) { asm volatile("sfence" ::: "memory"); }
  * @param d EDX value will be stores here
  */
 inline static void cpuid(uint32_t code, uint32_t* a, uint32_t* b, uint32_t* c, uint32_t* d) {
-	asm volatile ("cpuid" : "=a"(*a), "=b"(*b), "=c"(*c), "=d"(*d) : "0"(code));
+	asm volatile ("cpuid" : "=a"(*a), "=b"(*b), "=c"(*c), "=d"(*d) : "0"(code), "2"(*c));
 }
 
 /** @brief Read MSR
@@ -335,9 +335,7 @@ uint32_t read_eip(void);
 inline static int system_init(void)
 {
 	gdt_install();
-#ifdef CONFIG_X86_32
 	apic_init();
-#endif
 #ifdef CONFIG_PCI
 	pci_init();
 #endif

arch/x86/kernel/apic.c

@@ -42,6 +42,13 @@
 #error RockCreek is not a SMP system
 #endif
 
+/* 
+ * Note that linker symbols are not variables, they have no memory allocated for
+ * maintaining a value, rather their address is their value.
+ */
+extern const void kernel_start;
+extern const void kernel_end;
+
 // IO APIC MMIO structure: write reg, then read or write data.
 typedef struct {
 	uint32_t reg;
@@ -53,7 +60,7 @@ static const apic_processor_entry_t* apic_processors[MAX_CORES] = {[0 ... MAX_CO
 static uint32_t boot_processor = MAX_CORES;
 static apic_mp_t* apic_mp = NULL;
 static apic_config_table_t* apic_config = NULL;
-static uint32_t lapic = 0;
+static size_t lapic = 0;
 static volatile ioapic_t* ioapic = NULL;
 static uint32_t icr = 0;
 static uint32_t ncores = 1;
@@ -329,7 +336,7 @@ void smp_start(uint32_t id)
 }
 #endif
 
-#if 1
+#ifdef CONFIG_X86_32
 static apic_mp_t* search_apic(size_t base, size_t limit) {
 	size_t ptr;
 	apic_mp_t* tmp;
@@ -446,9 +453,11 @@ int map_apic(void)
 	if (!has_apic())
 		return -ENXIO;
 
+#ifdef CONFIG_X86_32
 	lapic = map_region(0 /*lapic*/, lapic, 1, MAP_KERNEL_SPACE|MAP_NO_CACHE);
 	if (BUILTIN_EXPECT(!lapic, 0))
 		return -ENXIO;
+#endif
 	kprintf("Mapped LAPIC at 0x%x\n", lapic);
 
 	if (ioapic) {
@@ -569,12 +578,15 @@ static int apic_probe(void)
 	int isa_bus = -1;
 
 #if 1
+#ifdef CONFIG_X86_32
 	apic_mp = search_apic(0xF0000, 0x100000);
 	if (apic_mp)
 		goto found_mp;
 	apic_mp = search_apic(0x9F000, 0xA0000);
 	if (apic_mp)
 		goto found_mp;
+#elif defined(CONFIG_X86_64)
+#endif
 #else
 	// searching MP signature in the reserved memory areas
 	if (mb_info && (mb_info->flags & MULTIBOOT_INFO_MEM_MAP)) {
@@ -620,7 +632,7 @@ found_mp:
 		goto no_mp;
 	}
 
-	apic_config = (apic_config_table_t*) apic_mp->mp_config;
+	apic_config = (apic_config_table_t*) ((size_t) apic_mp->mp_config);
 	if (!apic_config || strncmp((void*) &apic_config->signature, "PCMP", 4) !=0) {
 		kputs("Invalid MP config table\n");
 		goto no_mp;
@@ -693,11 +705,16 @@ check_lapic:
 	if (apic_config) {
 		lapic = apic_config->lapic;
 	} else {
-		uint32_t edx, dummy;
+		uint32_t edx, dummy=0;
 
 		cpuid(0x1, &dummy, &dummy, &dummy, &edx);
 		if (edx & (1 << 9))
+#ifdef CONFIG_X86_32
 			lapic = 0xFEE00000;
+#else
+			// On a x64 system, we already map the lapic below the kernel
+			lapic = (size_t)&kernel_start - 0x1000;
+#endif
 	}
 
 	if (!lapic)

arch/x86/kernel/entry64.asm

@@ -177,6 +177,30 @@ L0:
     or ebx, 0x00000003
     mov DWORD [edi], ebx
 
+    ; check if lapic is available
+    push eax
+    push ebx
+    push ecx
+    push edx
+    mov eax, 1
+    cpuid
+    and edx, 0x200
+    cmp edx, 0
+    je no_lapic
+    ; map lapic at 0xFEE00000 below the kernel
+    mov edi, kernel_start
+    sub edi, 0x1000
+    shr edi, 9   ; (edi >> 12) * 8
+    add edi, boot_pt
+    mov ebx, 0xFEE00000
+    or ebx, 0x00000013
+    mov DWORD [edi], ebx
+no_lapic:
+    pop edx
+    pop ecx
+    pop ebx
+    pop eax
+
     extern kernel_start           ; defined in linker script
     extern kernel_end
     mov edi, kernel_start