src/cpu/x86/lapic/lapic_cpu_init.c - coreboot - Gitiles

 /*
 	2005.12 yhlu add coreboot_ram cross the vga font buffer handling
 	2005.12 yhlu add CONFIG_RAMBASE above 1M support for SMP
 	2008.05 stepan add support for going back to sipi wait state
 */

 #include <cpu/x86/lapic.h>
 #include <delay.h>
 #include <string.h>
 #include <console/console.h>
 #include <arch/hlt.h>
 #include <device/device.h>
 #include <device/path.h>
 #include <smp/atomic.h>
 #include <smp/spinlock.h>
 #include <cpu/cpu.h>

 #if CONFIG_SMP == 1

 #if CONFIG_RAMBASE >= 0x100000
 /* This is a lot more paranoid now, since Linux can NOT handle
  * being told there is a CPU when none exists. So any errors
  * will return 0, meaning no CPU.
  *
  * We actually handling that case by noting which cpus startup
  * and not telling anyone about the ones that dont.
  */
 static unsigned long get_valid_start_eip(unsigned long orig_start_eip)
 {
 	return (unsigned long)orig_start_eip & 0xffff; // 16 bit to avoid 0xa0000
 }
 #endif

 #if CONFIG_HAVE_ACPI_RESUME == 1
 char *lowmem_backup;
 char *lowmem_backup_ptr;
 int  lowmem_backup_size;
 #endif

 extern char _secondary_start[];

 static void copy_secondary_start_to_1m_below(void)
 {
 #if CONFIG_RAMBASE >= 0x100000
 	extern char _secondary_start_end[];
 	unsigned long code_size;
 	unsigned long start_eip;

 	/* _secondary_start need to be masked 20 above bit, because 16 bit code in secondary.S
 	   Also We need to copy the _secondary_start to the below 1M region
 	*/
 	start_eip = get_valid_start_eip((unsigned long)_secondary_start);
 	code_size = (unsigned long)_secondary_start_end - (unsigned long)_secondary_start;

 #if CONFIG_HAVE_ACPI_RESUME == 1
 	/* need to save it for RAM resume */
 	lowmem_backup_size = code_size;
 	lowmem_backup = malloc(code_size);
 	lowmem_backup_ptr = (char *)start_eip;

 	if (lowmem_backup == NULL)
 		die("Out of backup memory\n");

 	memcpy(lowmem_backup, lowmem_backup_ptr, lowmem_backup_size);
 #endif
 	/* copy the _secondary_start to the ram below 1M*/
 	memcpy((unsigned char *)start_eip, (unsigned char *)_secondary_start, code_size);

 	printk_debug("start_eip=0x%08lx, offset=0x%08lx, code_size=0x%08lx\n", start_eip, ((unsigned long)_secondary_start - start_eip), code_size);
 #endif
 }

 static int lapic_start_cpu(unsigned long apicid)
 {
 	int timeout;
 	unsigned long send_status, accept_status, start_eip;
 	int j, num_starts, maxlvt;

 	/*
 	 * Starting actual IPI sequence...
 	 */

 	printk_spew("Asserting INIT.\n");

 	/*
 	 * Turn INIT on target chip
 	 */
 	lapic_write_around(LAPIC_ICR2, SET_LAPIC_DEST_FIELD(apicid));

 	/*
 	 * Send IPI
 	 */

 	lapic_write_around(LAPIC_ICR, LAPIC_INT_LEVELTRIG | LAPIC_INT_ASSERT
 				| LAPIC_DM_INIT);

 	printk_spew("Waiting for send to finish...\n");
 	timeout = 0;
 	do {
 		printk_spew("+");
 		udelay(100);
 		send_status = lapic_read(LAPIC_ICR) & LAPIC_ICR_BUSY;
 	} while (send_status && (timeout++ < 1000));
 	if (timeout >= 1000) {
 		printk_err("CPU %ld: First apic write timed out. Disabling\n",
 			 apicid);
 		// too bad.
 		printk_err("ESR is 0x%lx\n", lapic_read(LAPIC_ESR));
 		if (lapic_read(LAPIC_ESR)) {
 			printk_err("Try to reset ESR\n");
 			lapic_write_around(LAPIC_ESR, 0);
 			printk_err("ESR is 0x%lx\n", lapic_read(LAPIC_ESR));
 		}
 		return 0;
 	}
 	mdelay(10);

 	printk_spew("Deasserting INIT.\n");

 	/* Target chip */
 	lapic_write_around(LAPIC_ICR2, SET_LAPIC_DEST_FIELD(apicid));

 	/* Send IPI */
 	lapic_write_around(LAPIC_ICR, LAPIC_INT_LEVELTRIG | LAPIC_DM_INIT);

 	printk_spew("Waiting for send to finish...\n");
 	timeout = 0;
 	do {
 		printk_spew("+");
 		udelay(100);
 		send_status = lapic_read(LAPIC_ICR) & LAPIC_ICR_BUSY;
 	} while (send_status && (timeout++ < 1000));
 	if (timeout >= 1000) {
 		printk_err("CPU %ld: Second apic write timed out. Disabling\n",
 			 apicid);
 		// too bad.
 		return 0;
 	}

 #if CONFIG_RAMBASE >= 0x100000
 	start_eip = get_valid_start_eip((unsigned long)_secondary_start);
 #else
 	start_eip = (unsigned long)_secondary_start;
 #endif

 	num_starts = 2;

 	/*
 	 * Run STARTUP IPI loop.
 	 */
 	printk_spew("#startup loops: %d.\n", num_starts);

 	maxlvt = 4;

 	for (j = 1; j <= num_starts; j++) {
 		printk_spew("Sending STARTUP #%d to %lu.\n", j, apicid);
 		lapic_read_around(LAPIC_SPIV);
 		lapic_write(LAPIC_ESR, 0);
 		lapic_read(LAPIC_ESR);
 		printk_spew("After apic_write.\n");

 		/*
 		 * STARTUP IPI
 		 */

 		/* Target chip */
 		lapic_write_around(LAPIC_ICR2, SET_LAPIC_DEST_FIELD(apicid));

 		/* Boot on the stack */
 		/* Kick the second */
 		lapic_write_around(LAPIC_ICR, LAPIC_DM_STARTUP
 					| (start_eip >> 12));

 		/*
 		 * Give the other CPU some time to accept the IPI.
 		 */
 		udelay(300);

 		printk_spew("Startup point 1.\n");

 		printk_spew("Waiting for send to finish...\n");
 		timeout = 0;
 		do {
 			printk_spew("+");
 			udelay(100);
 			send_status = lapic_read(LAPIC_ICR) & LAPIC_ICR_BUSY;
 		} while (send_status && (timeout++ < 1000));

 		/*
 		 * Give the other CPU some time to accept the IPI.
 		 */
 		udelay(200);
 		/*
 		 * Due to the Pentium erratum 3AP.
 		 */
 		if (maxlvt > 3) {
 			lapic_read_around(LAPIC_SPIV);
 			lapic_write(LAPIC_ESR, 0);
 		}
 		accept_status = (lapic_read(LAPIC_ESR) & 0xEF);
 		if (send_status || accept_status)
 			break;
 	}
 	printk_spew("After Startup.\n");
 	if (send_status)
 		printk_warning("APIC never delivered???\n");
 	if (accept_status)
 		printk_warning("APIC delivery error (%lx).\n", accept_status);
 	if (send_status || accept_status)
 		return 0;
 	return 1;
 }

 /* Number of cpus that are currently running in coreboot */
 static atomic_t active_cpus = ATOMIC_INIT(1);

 /* start_cpu_lock covers last_cpu_index and secondary_stack.
  * Only starting one cpu at a time let's me remove the logic
  * for select the stack from assembly language.
  *
  * In addition communicating by variables to the cpu I
  * am starting allows me to veryify it has started before
  * start_cpu returns.
  */

 static spinlock_t start_cpu_lock = SPIN_LOCK_UNLOCKED;
 static unsigned last_cpu_index = 0;
 volatile unsigned long secondary_stack;

 int start_cpu(device_t cpu)
 {
 	extern unsigned char _estack[];
 	struct cpu_info *info;
 	unsigned long stack_end;
 	unsigned long apicid;
 	unsigned long index;
 	unsigned long count;
 	int result;

 	spin_lock(&start_cpu_lock);

 	/* Get the cpu's apicid */
 	apicid = cpu->path.apic.apic_id;

 	/* Get an index for the new processor */
 	index = ++last_cpu_index;

 	/* Find end of the new processors stack */
 #if (CONFIG_RAMTOP>0x100000) && (CONFIG_RAMBASE < 0x100000) && ((CONFIG_CONSOLE_VGA==1) || (CONFIG_PCI_ROM_RUN == 1))
 	if(index<1) { // only keep bsp on low
 		stack_end = ((unsigned long)_estack) - (CONFIG_STACK_SIZE*index) - sizeof(struct cpu_info);
 	} else {
 		// for all APs, let use stack after pgtbl, 20480 is the pgtbl size for every cpu
 		stack_end = 0x100000+(20480 + CONFIG_STACK_SIZE)*CONFIG_MAX_CPUS - (CONFIG_STACK_SIZE*index);
 #if (0x100000+(20480 + CONFIG_STACK_SIZE)*CONFIG_MAX_CPUS) > (CONFIG_RAMTOP)
 		#warning "We may need to increase CONFIG_RAMTOP, it need to be more than (0x100000+(20480 + CONFIG_STACK_SIZE)*CONFIG_MAX_CPUS)\n"
 #endif
 		if(stack_end > (CONFIG_RAMTOP)) {
 			printk_debug("start_cpu: Please increase the CONFIG_RAMTOP more than %luK\n", stack_end);
 			die("Can not go on\n");
 		}
 		stack_end -= sizeof(struct cpu_info);
 	}
 #else
 	stack_end = ((unsigned long)_estack) - (CONFIG_STACK_SIZE*index) - sizeof(struct cpu_info);
 #endif


 	/* Record the index and which cpu structure we are using */
 	info = (struct cpu_info *)stack_end;
 	info->index = index;
 	info->cpu   = cpu;

 	/* Advertise the new stack to start_cpu */
 	secondary_stack = stack_end;

 	/* Until the cpu starts up report the cpu is not enabled */
 	cpu->enabled = 0;
 	cpu->initialized = 0;

 	/* Start the cpu */
 	result = lapic_start_cpu(apicid);

 	if (result) {
 		result = 0;
 		/* Wait 1s or until the new the new cpu calls in */
 		for(count = 0; count < 100000 ; count++) {
 			if (secondary_stack == 0) {
 				result = 1;
 				break;
 			}
 			udelay(10);
 		}
 	}
 	secondary_stack = 0;
 	spin_unlock(&start_cpu_lock);
 	return result;
 }

 #if CONFIG_AP_IN_SIPI_WAIT == 1
 /**
  * Normally this function is defined in lapic.h as an always inline function
  * that just keeps the CPU in a hlt() loop. This does not work on all CPUs.
  * I think all hyperthreading CPUs might need this version, but I could only
  * verify this on the Intel Core Duo
  */
 void stop_this_cpu(void)
 {
 	int timeout;
 	unsigned long send_status;
 	unsigned long id;

 	id = lapic_read(LAPIC_ID) >> 24;

 	printk_debug("CPU %ld going down...\n", id);

 	/* send an LAPIC INIT to myself */
 	lapic_write_around(LAPIC_ICR2, SET_LAPIC_DEST_FIELD(id));
 	lapic_write_around(LAPIC_ICR, LAPIC_INT_LEVELTRIG | LAPIC_INT_ASSERT | LAPIC_DM_INIT);

 	/* wait for the ipi send to finish */
 #if 0
 	// When these two printk_spew calls are not removed, the
 	// machine will hang when log level is SPEW. Why?
 	printk_spew("Waiting for send to finish...\n");
 #endif
 	timeout = 0;
 	do {
 #if 0
 		printk_spew("+");
 #endif
 		udelay(100);
 		send_status = lapic_read(LAPIC_ICR) & LAPIC_ICR_BUSY;
 	} while (send_status && (timeout++ < 1000));
 	if (timeout >= 1000) {
 		printk_err("timed out\n");
 	}
 	mdelay(10);

 	printk_spew("Deasserting INIT.\n");
 	/* Deassert the LAPIC INIT */
 	lapic_write_around(LAPIC_ICR2, SET_LAPIC_DEST_FIELD(id));
 	lapic_write_around(LAPIC_ICR, LAPIC_INT_LEVELTRIG | LAPIC_DM_INIT);

 	printk_spew("Waiting for send to finish...\n");
 	timeout = 0;
 	do {
 		printk_spew("+");
 		udelay(100);
 		send_status = lapic_read(LAPIC_ICR) & LAPIC_ICR_BUSY;
 	} while (send_status && (timeout++ < 1000));
 	if (timeout >= 1000) {
 		printk_err("timed out\n");
 	}

 	while(1) {
 		hlt();
 	}
 }
 #endif

 /* C entry point of secondary cpus */
 void secondary_cpu_init(void)
 {
 	atomic_inc(&active_cpus);
 #if CONFIG_SERIAL_CPU_INIT == 1
   #if CONFIG_MAX_CPUS>2
 	spin_lock(&start_cpu_lock);
   #endif
 #endif
 	cpu_initialize();
 #if CONFIG_SERIAL_CPU_INIT == 1
   #if CONFIG_MAX_CPUS>2
 	spin_unlock(&start_cpu_lock);
   #endif
 #endif

 	atomic_dec(&active_cpus);

 	stop_this_cpu();
 }

 static void start_other_cpus(struct bus *cpu_bus, device_t bsp_cpu)
 {
 	device_t cpu;
 	/* Loop through the cpus once getting them started */

 	for(cpu = cpu_bus->children; cpu ; cpu = cpu->sibling) {
 		if (cpu->path.type != DEVICE_PATH_APIC) {
 			continue;
 		}
 	#if CONFIG_SERIAL_CPU_INIT == 0
 		if(cpu==bsp_cpu) {
 			continue;
 		}
 	#endif

 		if (!cpu->enabled) {
 			continue;
 		}

 		if (cpu->initialized) {
 			continue;
 		}

 		if (!start_cpu(cpu)) {
 			/* Record the error in cpu? */
 			printk_err("CPU 0x%02x would not start!\n",
 				cpu->path.apic.apic_id);
 		}
 #if CONFIG_SERIAL_CPU_INIT == 1
   #if CONFIG_MAX_CPUS>2
 		udelay(10);
   #endif
 #endif
 	}

 }

 static void wait_other_cpus_stop(struct bus *cpu_bus)
 {
 	device_t cpu;
 	int old_active_count, active_count;
 	/* Now loop until the other cpus have finished initializing */
 	old_active_count = 1;
 	active_count = atomic_read(&active_cpus);
 	while(active_count > 1) {
 		if (active_count != old_active_count) {
 			printk_info("Waiting for %d CPUS to stop\n", active_count - 1);
 			old_active_count = active_count;
 		}
 		udelay(10);
 		active_count = atomic_read(&active_cpus);
 	}
 	for(cpu = cpu_bus->children; cpu; cpu = cpu->sibling) {
 		if (cpu->path.type != DEVICE_PATH_APIC) {
 			continue;
 		}
 		if (!cpu->initialized) {
 			printk_err("CPU 0x%02x did not initialize!\n",
 				cpu->path.apic.apic_id);
 		}
 	}
 	printk_debug("All AP CPUs stopped\n");
 }

 #else /* CONFIG_SMP */
 #define initialize_other_cpus(root) do {} while(0)
 #endif /* CONFIG_SMP */

 void initialize_cpus(struct bus *cpu_bus)
 {
 	struct device_path cpu_path;
 	struct cpu_info *info;

 	/* Find the info struct for this cpu */
 	info = cpu_info();

 #if NEED_LAPIC == 1
 	/* Ensure the local apic is enabled */
 	enable_lapic();

 	/* Get the device path of the boot cpu */
 	cpu_path.type           = DEVICE_PATH_APIC;
 	cpu_path.apic.apic_id = lapicid();
 #else
 	/* Get the device path of the boot cpu */
 	cpu_path.type           = DEVICE_PATH_CPU;
 	cpu_path.cpu.id       = 0;
 #endif

 	/* Find the device structure for the boot cpu */
 	info->cpu = alloc_find_dev(cpu_bus, &cpu_path);

 #if CONFIG_SMP == 1
 	copy_secondary_start_to_1m_below(); // why here? In case some day we can start core1 in amd_sibling_init
 #endif

 #if CONFIG_HAVE_SMI_HANDLER
 	smm_init();
 #endif

 	cpus_ready_for_init();

 #if CONFIG_SMP == 1
 	#if CONFIG_SERIAL_CPU_INIT == 0
 	/* start all aps at first, so we can init ECC all together */
 	start_other_cpus(cpu_bus, info->cpu);
 	#endif
 #endif

 	/* Initialize the bootstrap processor */
 	cpu_initialize();

 #if CONFIG_SMP == 1
 	#if CONFIG_SERIAL_CPU_INIT == 1
 	start_other_cpus(cpu_bus, info->cpu);
 	#endif

 	/* Now wait the rest of the cpus stop*/
 	wait_other_cpus_stop(cpu_bus);
 #endif
 }
	/*
	2005.12 yhlu add coreboot_ram cross the vga font buffer handling
	2005.12 yhlu add CONFIG_RAMBASE above 1M support for SMP
	2008.05 stepan add support for going back to sipi wait state
	*/

	#include <cpu/x86/lapic.h>
	#include <delay.h>
	#include <string.h>
	#include <console/console.h>
	#include <arch/hlt.h>
	#include <device/device.h>
	#include <device/path.h>
	#include <smp/atomic.h>
	#include <smp/spinlock.h>
	#include <cpu/cpu.h>

	#if CONFIG_SMP == 1

	#if CONFIG_RAMBASE >= 0x100000
	/* This is a lot more paranoid now, since Linux can NOT handle
	* being told there is a CPU when none exists. So any errors
	* will return 0, meaning no CPU.
	*
	* We actually handling that case by noting which cpus startup
	* and not telling anyone about the ones that dont.
	*/
	static unsigned long get_valid_start_eip(unsigned long orig_start_eip)
	{
	return (unsigned long)orig_start_eip & 0xffff; // 16 bit to avoid 0xa0000
	}
	#endif

	#if CONFIG_HAVE_ACPI_RESUME == 1
	char *lowmem_backup;
	char *lowmem_backup_ptr;
	int lowmem_backup_size;
	#endif

	extern char _secondary_start[];

	static void copy_secondary_start_to_1m_below(void)
	{
	#if CONFIG_RAMBASE >= 0x100000
	extern char _secondary_start_end[];
	unsigned long code_size;
	unsigned long start_eip;

	/* _secondary_start need to be masked 20 above bit, because 16 bit code in secondary.S
	Also We need to copy the _secondary_start to the below 1M region
	*/
	start_eip = get_valid_start_eip((unsigned long)_secondary_start);
	code_size = (unsigned long)_secondary_start_end - (unsigned long)_secondary_start;

	#if CONFIG_HAVE_ACPI_RESUME == 1
	/* need to save it for RAM resume */
	lowmem_backup_size = code_size;
	lowmem_backup = malloc(code_size);
	lowmem_backup_ptr = (char *)start_eip;

	if (lowmem_backup == NULL)
	die("Out of backup memory\n");

	memcpy(lowmem_backup, lowmem_backup_ptr, lowmem_backup_size);
	#endif
	/* copy the _secondary_start to the ram below 1M*/
	memcpy((unsigned char )start_eip, (unsigned char )_secondary_start, code_size);

	printk_debug("start_eip=0x%08lx, offset=0x%08lx, code_size=0x%08lx\n", start_eip, ((unsigned long)_secondary_start - start_eip), code_size);
	#endif
	}

	static int lapic_start_cpu(unsigned long apicid)
	{
	int timeout;
	unsigned long send_status, accept_status, start_eip;
	int j, num_starts, maxlvt;

	/*
	* Starting actual IPI sequence...
	*/

	printk_spew("Asserting INIT.\n");

	/*
	* Turn INIT on target chip
	*/
	lapic_write_around(LAPIC_ICR2, SET_LAPIC_DEST_FIELD(apicid));

	/*
	* Send IPI
	*/

	lapic_write_around(LAPIC_ICR, LAPIC_INT_LEVELTRIG \| LAPIC_INT_ASSERT
	\| LAPIC_DM_INIT);

	printk_spew("Waiting for send to finish...\n");
	timeout = 0;
	do {
	printk_spew("+");
	udelay(100);
	send_status = lapic_read(LAPIC_ICR) & LAPIC_ICR_BUSY;
	} while (send_status && (timeout++ < 1000));
	if (timeout >= 1000) {
	printk_err("CPU %ld: First apic write timed out. Disabling\n",
	apicid);
	// too bad.
	printk_err("ESR is 0x%lx\n", lapic_read(LAPIC_ESR));
	if (lapic_read(LAPIC_ESR)) {
	printk_err("Try to reset ESR\n");
	lapic_write_around(LAPIC_ESR, 0);
	printk_err("ESR is 0x%lx\n", lapic_read(LAPIC_ESR));
	}
	return 0;
	}
	mdelay(10);

	printk_spew("Deasserting INIT.\n");

	/* Target chip */
	lapic_write_around(LAPIC_ICR2, SET_LAPIC_DEST_FIELD(apicid));

	/* Send IPI */
	lapic_write_around(LAPIC_ICR, LAPIC_INT_LEVELTRIG \| LAPIC_DM_INIT);

	printk_spew("Waiting for send to finish...\n");
	timeout = 0;
	do {
	printk_spew("+");
	udelay(100);
	send_status = lapic_read(LAPIC_ICR) & LAPIC_ICR_BUSY;
	} while (send_status && (timeout++ < 1000));
	if (timeout >= 1000) {
	printk_err("CPU %ld: Second apic write timed out. Disabling\n",
	apicid);
	// too bad.
	return 0;
	}

	#if CONFIG_RAMBASE >= 0x100000
	start_eip = get_valid_start_eip((unsigned long)_secondary_start);
	#else
	start_eip = (unsigned long)_secondary_start;
	#endif

	num_starts = 2;

	/*
	* Run STARTUP IPI loop.
	*/
	printk_spew("#startup loops: %d.\n", num_starts);

	maxlvt = 4;

	for (j = 1; j <= num_starts; j++) {
	printk_spew("Sending STARTUP #%d to %lu.\n", j, apicid);
	lapic_read_around(LAPIC_SPIV);
	lapic_write(LAPIC_ESR, 0);
	lapic_read(LAPIC_ESR);
	printk_spew("After apic_write.\n");

	/*
	* STARTUP IPI
	*/

	/* Target chip */
	lapic_write_around(LAPIC_ICR2, SET_LAPIC_DEST_FIELD(apicid));

	/* Boot on the stack */
	/* Kick the second */
	lapic_write_around(LAPIC_ICR, LAPIC_DM_STARTUP
	\| (start_eip >> 12));

	/*
	* Give the other CPU some time to accept the IPI.
	*/
	udelay(300);

	printk_spew("Startup point 1.\n");

	printk_spew("Waiting for send to finish...\n");
	timeout = 0;
	do {
	printk_spew("+");
	udelay(100);
	send_status = lapic_read(LAPIC_ICR) & LAPIC_ICR_BUSY;
	} while (send_status && (timeout++ < 1000));

	/*
	* Give the other CPU some time to accept the IPI.
	*/
	udelay(200);
	/*
	* Due to the Pentium erratum 3AP.
	*/
	if (maxlvt > 3) {
	lapic_read_around(LAPIC_SPIV);
	lapic_write(LAPIC_ESR, 0);
	}
	accept_status = (lapic_read(LAPIC_ESR) & 0xEF);
	if (send_status \|\| accept_status)
	break;
	}
	printk_spew("After Startup.\n");
	if (send_status)
	printk_warning("APIC never delivered???\n");
	if (accept_status)
	printk_warning("APIC delivery error (%lx).\n", accept_status);
	if (send_status \|\| accept_status)
	return 0;
	return 1;
	}

	/* Number of cpus that are currently running in coreboot */
	static atomic_t active_cpus = ATOMIC_INIT(1);

	/* start_cpu_lock covers last_cpu_index and secondary_stack.
	* Only starting one cpu at a time let's me remove the logic
	* for select the stack from assembly language.
	*
	* In addition communicating by variables to the cpu I
	* am starting allows me to veryify it has started before
	* start_cpu returns.
	*/

	static spinlock_t start_cpu_lock = SPIN_LOCK_UNLOCKED;
	static unsigned last_cpu_index = 0;
	volatile unsigned long secondary_stack;

	int start_cpu(device_t cpu)
	{
	extern unsigned char _estack[];
	struct cpu_info *info;
	unsigned long stack_end;
	unsigned long apicid;
	unsigned long index;
	unsigned long count;
	int result;

	spin_lock(&start_cpu_lock);

	/* Get the cpu's apicid */
	apicid = cpu->path.apic.apic_id;

	/* Get an index for the new processor */
	index = ++last_cpu_index;

	/* Find end of the new processors stack */
	#if (CONFIG_RAMTOP>0x100000) && (CONFIG_RAMBASE < 0x100000) && ((CONFIG_CONSOLE_VGA==1) \|\| (CONFIG_PCI_ROM_RUN == 1))
	if(index<1) { // only keep bsp on low
	stack_end = ((unsigned long)_estack) - (CONFIG_STACK_SIZE*index) - sizeof(struct cpu_info);
	} else {
	// for all APs, let use stack after pgtbl, 20480 is the pgtbl size for every cpu
	stack_end = 0x100000+(20480 + CONFIG_STACK_SIZE)CONFIG_MAX_CPUS - (CONFIG_STACK_SIZEindex);
	#if (0x100000+(20480 + CONFIG_STACK_SIZE)*CONFIG_MAX_CPUS) > (CONFIG_RAMTOP)
	#warning "We may need to increase CONFIG_RAMTOP, it need to be more than (0x100000+(20480 + CONFIG_STACK_SIZE)*CONFIG_MAX_CPUS)\n"
	#endif
	if(stack_end > (CONFIG_RAMTOP)) {
	printk_debug("start_cpu: Please increase the CONFIG_RAMTOP more than %luK\n", stack_end);
	die("Can not go on\n");
	}
	stack_end -= sizeof(struct cpu_info);
	}
	#else
	stack_end = ((unsigned long)_estack) - (CONFIG_STACK_SIZE*index) - sizeof(struct cpu_info);
	#endif


	/* Record the index and which cpu structure we are using */
	info = (struct cpu_info *)stack_end;
	info->index = index;
	info->cpu = cpu;

	/* Advertise the new stack to start_cpu */
	secondary_stack = stack_end;

	/* Until the cpu starts up report the cpu is not enabled */
	cpu->enabled = 0;
	cpu->initialized = 0;

	/* Start the cpu */
	result = lapic_start_cpu(apicid);

	if (result) {
	result = 0;
	/* Wait 1s or until the new the new cpu calls in */
	for(count = 0; count < 100000 ; count++) {
	if (secondary_stack == 0) {
	result = 1;
	break;
	}
	udelay(10);
	}
	}
	secondary_stack = 0;
	spin_unlock(&start_cpu_lock);
	return result;
	}

	#if CONFIG_AP_IN_SIPI_WAIT == 1
	/**
	* Normally this function is defined in lapic.h as an always inline function
	* that just keeps the CPU in a hlt() loop. This does not work on all CPUs.
	* I think all hyperthreading CPUs might need this version, but I could only
	* verify this on the Intel Core Duo
	*/
	void stop_this_cpu(void)
	{
	int timeout;
	unsigned long send_status;
	unsigned long id;

	id = lapic_read(LAPIC_ID) >> 24;

	printk_debug("CPU %ld going down...\n", id);

	/* send an LAPIC INIT to myself */
	lapic_write_around(LAPIC_ICR2, SET_LAPIC_DEST_FIELD(id));
	lapic_write_around(LAPIC_ICR, LAPIC_INT_LEVELTRIG \| LAPIC_INT_ASSERT \| LAPIC_DM_INIT);

	/* wait for the ipi send to finish */
	#if 0
	// When these two printk_spew calls are not removed, the
	// machine will hang when log level is SPEW. Why?
	printk_spew("Waiting for send to finish...\n");
	#endif
	timeout = 0;
	do {
	#if 0
	printk_spew("+");
	#endif
	udelay(100);
	send_status = lapic_read(LAPIC_ICR) & LAPIC_ICR_BUSY;
	} while (send_status && (timeout++ < 1000));
	if (timeout >= 1000) {
	printk_err("timed out\n");
	}
	mdelay(10);

	printk_spew("Deasserting INIT.\n");
	/* Deassert the LAPIC INIT */
	lapic_write_around(LAPIC_ICR2, SET_LAPIC_DEST_FIELD(id));
	lapic_write_around(LAPIC_ICR, LAPIC_INT_LEVELTRIG \| LAPIC_DM_INIT);

	printk_spew("Waiting for send to finish...\n");
	timeout = 0;
	do {
	printk_spew("+");
	udelay(100);
	send_status = lapic_read(LAPIC_ICR) & LAPIC_ICR_BUSY;
	} while (send_status && (timeout++ < 1000));
	if (timeout >= 1000) {
	printk_err("timed out\n");
	}

	while(1) {
	hlt();
	}
	}
	#endif

	/* C entry point of secondary cpus */
	void secondary_cpu_init(void)
	{
	atomic_inc(&active_cpus);
	#if CONFIG_SERIAL_CPU_INIT == 1
	#if CONFIG_MAX_CPUS>2
	spin_lock(&start_cpu_lock);
	#endif
	#endif
	cpu_initialize();
	#if CONFIG_SERIAL_CPU_INIT == 1
	#if CONFIG_MAX_CPUS>2
	spin_unlock(&start_cpu_lock);
	#endif
	#endif

	atomic_dec(&active_cpus);

	stop_this_cpu();
	}

	static void start_other_cpus(struct bus *cpu_bus, device_t bsp_cpu)
	{
	device_t cpu;
	/* Loop through the cpus once getting them started */

	for(cpu = cpu_bus->children; cpu ; cpu = cpu->sibling) {
	if (cpu->path.type != DEVICE_PATH_APIC) {
	continue;
	}
	#if CONFIG_SERIAL_CPU_INIT == 0
	if(cpu==bsp_cpu) {
	continue;
	}
	#endif

	if (!cpu->enabled) {
	continue;
	}

	if (cpu->initialized) {
	continue;
	}

	if (!start_cpu(cpu)) {
	/* Record the error in cpu? */
	printk_err("CPU 0x%02x would not start!\n",
	cpu->path.apic.apic_id);
	}
	#if CONFIG_SERIAL_CPU_INIT == 1
	#if CONFIG_MAX_CPUS>2
	udelay(10);
	#endif
	#endif
	}

	}

	static void wait_other_cpus_stop(struct bus *cpu_bus)
	{
	device_t cpu;
	int old_active_count, active_count;
	/* Now loop until the other cpus have finished initializing */
	old_active_count = 1;
	active_count = atomic_read(&active_cpus);
	while(active_count > 1) {
	if (active_count != old_active_count) {
	printk_info("Waiting for %d CPUS to stop\n", active_count - 1);
	old_active_count = active_count;
	}
	udelay(10);
	active_count = atomic_read(&active_cpus);
	}
	for(cpu = cpu_bus->children; cpu; cpu = cpu->sibling) {
	if (cpu->path.type != DEVICE_PATH_APIC) {
	continue;
	}
	if (!cpu->initialized) {
	printk_err("CPU 0x%02x did not initialize!\n",
	cpu->path.apic.apic_id);
	}
	}
	printk_debug("All AP CPUs stopped\n");
	}

	#else /* CONFIG_SMP */
	#define initialize_other_cpus(root) do {} while(0)
	#endif /* CONFIG_SMP */

	void initialize_cpus(struct bus *cpu_bus)
	{
	struct device_path cpu_path;
	struct cpu_info *info;

	/* Find the info struct for this cpu */
	info = cpu_info();

	#if NEED_LAPIC == 1
	/* Ensure the local apic is enabled */
	enable_lapic();

	/* Get the device path of the boot cpu */
	cpu_path.type = DEVICE_PATH_APIC;
	cpu_path.apic.apic_id = lapicid();
	#else
	/* Get the device path of the boot cpu */
	cpu_path.type = DEVICE_PATH_CPU;
	cpu_path.cpu.id = 0;
	#endif

	/* Find the device structure for the boot cpu */
	info->cpu = alloc_find_dev(cpu_bus, &cpu_path);

	#if CONFIG_SMP == 1
	copy_secondary_start_to_1m_below(); // why here? In case some day we can start core1 in amd_sibling_init
	#endif

	#if CONFIG_HAVE_SMI_HANDLER
	smm_init();
	#endif

	cpus_ready_for_init();

	#if CONFIG_SMP == 1
	#if CONFIG_SERIAL_CPU_INIT == 0
	/* start all aps at first, so we can init ECC all together */
	start_other_cpus(cpu_bus, info->cpu);
	#endif
	#endif

	/* Initialize the bootstrap processor */
	cpu_initialize();

	#if CONFIG_SMP == 1
	#if CONFIG_SERIAL_CPU_INIT == 1
	start_other_cpus(cpu_bus, info->cpu);
	#endif

	/* Now wait the rest of the cpus stop*/
	wait_other_cpus_stop(cpu_bus);
	#endif
	}