arch/x86/cpu/i386/cpu.c - filogic/uboot - Gitiles

 // SPDX-License-Identifier: GPL-2.0+
 /*
  * (C) Copyright 2008-2011
  * Graeme Russ, <graeme.russ@gmail.com>
  *
  * (C) Copyright 2002
  * Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
  *
  * (C) Copyright 2002
  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
  * Marius Groeger <mgroeger@sysgo.de>
  *
  * (C) Copyright 2002
  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
  * Alex Zuepke <azu@sysgo.de>
  *
  * Part of this file is adapted from coreboot
  * src/arch/x86/lib/cpu.c
  */

 #include <common.h>
 #include <malloc.h>
 #include <asm/control_regs.h>
 #include <asm/cpu.h>
 #include <asm/mp.h>
 #include <asm/msr.h>
 #include <asm/mtrr.h>
 #include <asm/processor-flags.h>

 DECLARE_GLOBAL_DATA_PTR;

 /*
  * Constructor for a conventional segment GDT (or LDT) entry
  * This is a macro so it can be used in initialisers
  */
 #define GDT_ENTRY(flags, base, limit)			\
 	((((base)  & 0xff000000ULL) << (56-24)) |	\
 	 (((flags) & 0x0000f0ffULL) << 40) |		\
 	 (((limit) & 0x000f0000ULL) << (48-16)) |	\
 	 (((base)  & 0x00ffffffULL) << 16) |		\
 	 (((limit) & 0x0000ffffULL)))

 struct gdt_ptr {
 	u16 len;
 	u32 ptr;
 } __packed;

 struct cpu_device_id {
 	unsigned vendor;
 	unsigned device;
 };

 struct cpuinfo_x86 {
 	uint8_t x86;            /* CPU family */
 	uint8_t x86_vendor;     /* CPU vendor */
 	uint8_t x86_model;
 	uint8_t x86_mask;
 };

 /*
  * List of cpu vendor strings along with their normalized
  * id values.
  */
 static const struct {
 	int vendor;
 	const char *name;
 } x86_vendors[] = {
 	{ X86_VENDOR_INTEL,     "GenuineIntel", },
 	{ X86_VENDOR_CYRIX,     "CyrixInstead", },
 	{ X86_VENDOR_AMD,       "AuthenticAMD", },
 	{ X86_VENDOR_UMC,       "UMC UMC UMC ", },
 	{ X86_VENDOR_NEXGEN,    "NexGenDriven", },
 	{ X86_VENDOR_CENTAUR,   "CentaurHauls", },
 	{ X86_VENDOR_RISE,      "RiseRiseRise", },
 	{ X86_VENDOR_TRANSMETA, "GenuineTMx86", },
 	{ X86_VENDOR_TRANSMETA, "TransmetaCPU", },
 	{ X86_VENDOR_NSC,       "Geode by NSC", },
 	{ X86_VENDOR_SIS,       "SiS SiS SiS ", },
 };

 static void load_ds(u32 segment)
 {
 	asm volatile("movl %0, %%ds" : : "r" (segment * X86_GDT_ENTRY_SIZE));
 }

 static void load_es(u32 segment)
 {
 	asm volatile("movl %0, %%es" : : "r" (segment * X86_GDT_ENTRY_SIZE));
 }

 static void load_fs(u32 segment)
 {
 	asm volatile("movl %0, %%fs" : : "r" (segment * X86_GDT_ENTRY_SIZE));
 }

 static void load_gs(u32 segment)
 {
 	asm volatile("movl %0, %%gs" : : "r" (segment * X86_GDT_ENTRY_SIZE));
 }

 static void load_ss(u32 segment)
 {
 	asm volatile("movl %0, %%ss" : : "r" (segment * X86_GDT_ENTRY_SIZE));
 }

 static void load_gdt(const u64 *boot_gdt, u16 num_entries)
 {
 	struct gdt_ptr gdt;

 	gdt.len = (num_entries * X86_GDT_ENTRY_SIZE) - 1;
 	gdt.ptr = (ulong)boot_gdt;

 	asm volatile("lgdtl %0\n" : : "m" (gdt));
 }

 void arch_setup_gd(gd_t *new_gd)
 {
 	u64 *gdt_addr;

 	gdt_addr = new_gd->arch.gdt;

 	/*
 	 * CS: code, read/execute, 4 GB, base 0
 	 *
 	 * Some OS (like VxWorks) requires GDT entry 1 to be the 32-bit CS
 	 */
 	gdt_addr[X86_GDT_ENTRY_UNUSED] = GDT_ENTRY(0xc09b, 0, 0xfffff);
 	gdt_addr[X86_GDT_ENTRY_32BIT_CS] = GDT_ENTRY(0xc09b, 0, 0xfffff);

 	/* DS: data, read/write, 4 GB, base 0 */
 	gdt_addr[X86_GDT_ENTRY_32BIT_DS] = GDT_ENTRY(0xc093, 0, 0xfffff);

 	/* FS: data, read/write, 4 GB, base (Global Data Pointer) */
 	new_gd->arch.gd_addr = new_gd;
 	gdt_addr[X86_GDT_ENTRY_32BIT_FS] = GDT_ENTRY(0xc093,
 		     (ulong)&new_gd->arch.gd_addr, 0xfffff);

 	/* 16-bit CS: code, read/execute, 64 kB, base 0 */
 	gdt_addr[X86_GDT_ENTRY_16BIT_CS] = GDT_ENTRY(0x009b, 0, 0x0ffff);

 	/* 16-bit DS: data, read/write, 64 kB, base 0 */
 	gdt_addr[X86_GDT_ENTRY_16BIT_DS] = GDT_ENTRY(0x0093, 0, 0x0ffff);

 	gdt_addr[X86_GDT_ENTRY_16BIT_FLAT_CS] = GDT_ENTRY(0x809b, 0, 0xfffff);
 	gdt_addr[X86_GDT_ENTRY_16BIT_FLAT_DS] = GDT_ENTRY(0x8093, 0, 0xfffff);

 	load_gdt(gdt_addr, X86_GDT_NUM_ENTRIES);
 	load_ds(X86_GDT_ENTRY_32BIT_DS);
 	load_es(X86_GDT_ENTRY_32BIT_DS);
 	load_gs(X86_GDT_ENTRY_32BIT_DS);
 	load_ss(X86_GDT_ENTRY_32BIT_DS);
 	load_fs(X86_GDT_ENTRY_32BIT_FS);
 }

 #ifdef CONFIG_HAVE_FSP
 /*
  * Setup FSP execution environment GDT
  *
  * Per Intel FSP external architecture specification, before calling any FSP
  * APIs, we need make sure the system is in flat 32-bit mode and both the code
  * and data selectors should have full 4GB access range. Here we reuse the one
  * we used in arch/x86/cpu/start16.S, and reload the segement registers.
  */
 void setup_fsp_gdt(void)
 {
 	load_gdt((const u64 *)(gdt_rom + CONFIG_RESET_SEG_START), 4);
 	load_ds(X86_GDT_ENTRY_32BIT_DS);
 	load_ss(X86_GDT_ENTRY_32BIT_DS);
 	load_es(X86_GDT_ENTRY_32BIT_DS);
 	load_fs(X86_GDT_ENTRY_32BIT_DS);
 	load_gs(X86_GDT_ENTRY_32BIT_DS);
 }
 #endif

 /*
  * Cyrix CPUs without cpuid or with cpuid not yet enabled can be detected
  * by the fact that they preserve the flags across the division of 5/2.
  * PII and PPro exhibit this behavior too, but they have cpuid available.
  */

 /*
  * Perform the Cyrix 5/2 test. A Cyrix won't change
  * the flags, while other 486 chips will.
  */
 static inline int test_cyrix_52div(void)
 {
 	unsigned int test;

 	__asm__ __volatile__(
 	     "sahf\n\t"		/* clear flags (%eax = 0x0005) */
 	     "div %b2\n\t"	/* divide 5 by 2 */
 	     "lahf"		/* store flags into %ah */
 	     : "=a" (test)
 	     : "0" (5), "q" (2)
 	     : "cc");

 	/* AH is 0x02 on Cyrix after the divide.. */
 	return (unsigned char) (test >> 8) == 0x02;
 }

 /*
  *	Detect a NexGen CPU running without BIOS hypercode new enough
  *	to have CPUID. (Thanks to Herbert Oppmann)
  */
 static int deep_magic_nexgen_probe(void)
 {
 	int ret;

 	__asm__ __volatile__ (
 		"	movw	$0x5555, %%ax\n"
 		"	xorw	%%dx,%%dx\n"
 		"	movw	$2, %%cx\n"
 		"	divw	%%cx\n"
 		"	movl	$0, %%eax\n"
 		"	jnz	1f\n"
 		"	movl	$1, %%eax\n"
 		"1:\n"
 		: "=a" (ret) : : "cx", "dx");
 	return  ret;
 }

 static bool has_cpuid(void)
 {
 	return flag_is_changeable_p(X86_EFLAGS_ID);
 }

 static bool has_mtrr(void)
 {
 	return cpuid_edx(0x00000001) & (1 << 12) ? true : false;
 }

 static int build_vendor_name(char *vendor_name)
 {
 	struct cpuid_result result;
 	result = cpuid(0x00000000);
 	unsigned int *name_as_ints = (unsigned int *)vendor_name;

 	name_as_ints[0] = result.ebx;
 	name_as_ints[1] = result.edx;
 	name_as_ints[2] = result.ecx;

 	return result.eax;
 }

 static void identify_cpu(struct cpu_device_id *cpu)
 {
 	char vendor_name[16];
 	int i;

 	vendor_name[0] = '\0'; /* Unset */
 	cpu->device = 0; /* fix gcc 4.4.4 warning */

 	/* Find the id and vendor_name */
 	if (!has_cpuid()) {
 		/* Its a 486 if we can modify the AC flag */
 		if (flag_is_changeable_p(X86_EFLAGS_AC))
 			cpu->device = 0x00000400; /* 486 */
 		else
 			cpu->device = 0x00000300; /* 386 */
 		if ((cpu->device == 0x00000400) && test_cyrix_52div()) {
 			memcpy(vendor_name, "CyrixInstead", 13);
 			/* If we ever care we can enable cpuid here */
 		}
 		/* Detect NexGen with old hypercode */
 		else if (deep_magic_nexgen_probe())
 			memcpy(vendor_name, "NexGenDriven", 13);
 	}
 	if (has_cpuid()) {
 		int  cpuid_level;

 		cpuid_level = build_vendor_name(vendor_name);
 		vendor_name[12] = '\0';

 		/* Intel-defined flags: level 0x00000001 */
 		if (cpuid_level >= 0x00000001) {
 			cpu->device = cpuid_eax(0x00000001);
 		} else {
 			/* Have CPUID level 0 only unheard of */
 			cpu->device = 0x00000400;
 		}
 	}
 	cpu->vendor = X86_VENDOR_UNKNOWN;
 	for (i = 0; i < ARRAY_SIZE(x86_vendors); i++) {
 		if (memcmp(vendor_name, x86_vendors[i].name, 12) == 0) {
 			cpu->vendor = x86_vendors[i].vendor;
 			break;
 		}
 	}
 }

 static inline void get_fms(struct cpuinfo_x86 *c, uint32_t tfms)
 {
 	c->x86 = (tfms >> 8) & 0xf;
 	c->x86_model = (tfms >> 4) & 0xf;
 	c->x86_mask = tfms & 0xf;
 	if (c->x86 == 0xf)
 		c->x86 += (tfms >> 20) & 0xff;
 	if (c->x86 >= 0x6)
 		c->x86_model += ((tfms >> 16) & 0xF) << 4;
 }

 u32 cpu_get_family_model(void)
 {
 	return gd->arch.x86_device & 0x0fff0ff0;
 }

 u32 cpu_get_stepping(void)
 {
 	return gd->arch.x86_mask;
 }

 int x86_cpu_init_f(void)
 {
 	const u32 em_rst = ~X86_CR0_EM;
 	const u32 mp_ne_set = X86_CR0_MP | X86_CR0_NE;

 	if (ll_boot_init()) {
 		/* initialize FPU, reset EM, set MP and NE */
 		asm ("fninit\n" \
 		"movl %%cr0, %%eax\n" \
 		"andl %0, %%eax\n" \
 		"orl  %1, %%eax\n" \
 		"movl %%eax, %%cr0\n" \
 		: : "i" (em_rst), "i" (mp_ne_set) : "eax");
 	}

 	/* identify CPU via cpuid and store the decoded info into gd->arch */
 	if (has_cpuid()) {
 		struct cpu_device_id cpu;
 		struct cpuinfo_x86 c;

 		identify_cpu(&cpu);
 		get_fms(&c, cpu.device);
 		gd->arch.x86 = c.x86;
 		gd->arch.x86_vendor = cpu.vendor;
 		gd->arch.x86_model = c.x86_model;
 		gd->arch.x86_mask = c.x86_mask;
 		gd->arch.x86_device = cpu.device;

 		gd->arch.has_mtrr = has_mtrr();
 	}
 	/* Don't allow PCI region 3 to use memory in the 2-4GB memory hole */
 	gd->pci_ram_top = 0x80000000U;

 	/* Configure fixed range MTRRs for some legacy regions */
 	if (gd->arch.has_mtrr) {
 		u64 mtrr_cap;

 		mtrr_cap = native_read_msr(MTRR_CAP_MSR);
 		if (mtrr_cap & MTRR_CAP_FIX) {
 			/* Mark the VGA RAM area as uncacheable */
 			native_write_msr(MTRR_FIX_16K_A0000_MSR,
 					 MTRR_FIX_TYPE(MTRR_TYPE_UNCACHEABLE),
 					 MTRR_FIX_TYPE(MTRR_TYPE_UNCACHEABLE));

 			/*
 			 * Mark the PCI ROM area as cacheable to improve ROM
 			 * execution performance.
 			 */
 			native_write_msr(MTRR_FIX_4K_C0000_MSR,
 					 MTRR_FIX_TYPE(MTRR_TYPE_WRBACK),
 					 MTRR_FIX_TYPE(MTRR_TYPE_WRBACK));
 			native_write_msr(MTRR_FIX_4K_C8000_MSR,
 					 MTRR_FIX_TYPE(MTRR_TYPE_WRBACK),
 					 MTRR_FIX_TYPE(MTRR_TYPE_WRBACK));
 			native_write_msr(MTRR_FIX_4K_D0000_MSR,
 					 MTRR_FIX_TYPE(MTRR_TYPE_WRBACK),
 					 MTRR_FIX_TYPE(MTRR_TYPE_WRBACK));
 			native_write_msr(MTRR_FIX_4K_D8000_MSR,
 					 MTRR_FIX_TYPE(MTRR_TYPE_WRBACK),
 					 MTRR_FIX_TYPE(MTRR_TYPE_WRBACK));

 			/* Enable the fixed range MTRRs */
 			msr_setbits_64(MTRR_DEF_TYPE_MSR, MTRR_DEF_TYPE_FIX_EN);
 		}
 	}

 #ifdef CONFIG_I8254_TIMER
 	/* Set up the i8254 timer if required */
 	i8254_init();
 #endif

 	return 0;
 }

 void x86_enable_caches(void)
 {
 	unsigned long cr0;

 	cr0 = read_cr0();
 	cr0 &= ~(X86_CR0_NW | X86_CR0_CD);
 	write_cr0(cr0);
 	wbinvd();
 }
 void enable_caches(void) __attribute__((weak, alias("x86_enable_caches")));

 void x86_disable_caches(void)
 {
 	unsigned long cr0;

 	cr0 = read_cr0();
 	cr0 |= X86_CR0_NW | X86_CR0_CD;
 	wbinvd();
 	write_cr0(cr0);
 	wbinvd();
 }
 void disable_caches(void) __attribute__((weak, alias("x86_disable_caches")));

 int dcache_status(void)
 {
 	return !(read_cr0() & X86_CR0_CD);
 }

 void cpu_enable_paging_pae(ulong cr3)
 {
 	__asm__ __volatile__(
 		/* Load the page table address */
 		"movl	%0, %%cr3\n"
 		/* Enable pae */
 		"movl	%%cr4, %%eax\n"
 		"orl	$0x00000020, %%eax\n"
 		"movl	%%eax, %%cr4\n"
 		/* Enable paging */
 		"movl	%%cr0, %%eax\n"
 		"orl	$0x80000000, %%eax\n"
 		"movl	%%eax, %%cr0\n"
 		:
 		: "r" (cr3)
 		: "eax");
 }

 void cpu_disable_paging_pae(void)
 {
 	/* Turn off paging */
 	__asm__ __volatile__ (
 		/* Disable paging */
 		"movl	%%cr0, %%eax\n"
 		"andl	$0x7fffffff, %%eax\n"
 		"movl	%%eax, %%cr0\n"
 		/* Disable pae */
 		"movl	%%cr4, %%eax\n"
 		"andl	$0xffffffdf, %%eax\n"
 		"movl	%%eax, %%cr4\n"
 		:
 		:
 		: "eax");
 }

 static bool can_detect_long_mode(void)
 {
 	return cpuid_eax(0x80000000) > 0x80000000UL;
 }

 static bool has_long_mode(void)
 {
 	return cpuid_edx(0x80000001) & (1 << 29) ? true : false;
 }

 int cpu_has_64bit(void)
 {
 	return has_cpuid() && can_detect_long_mode() &&
 		has_long_mode();
 }

 #define PAGETABLE_BASE		0x80000
 #define PAGETABLE_SIZE		(6 * 4096)

 /**
  * build_pagetable() - build a flat 4GiB page table structure for 64-bti mode
  *
  * @pgtable: Pointer to a 24iKB block of memory
  */
 static void build_pagetable(uint32_t *pgtable)
 {
 	uint i;

 	memset(pgtable, '\0', PAGETABLE_SIZE);

 	/* Level 4 needs a single entry */
 	pgtable[0] = (ulong)&pgtable[1024] + 7;

 	/* Level 3 has one 64-bit entry for each GiB of memory */
 	for (i = 0; i < 4; i++)
 		pgtable[1024 + i * 2] = (ulong)&pgtable[2048] + 0x1000 * i + 7;

 	/* Level 2 has 2048 64-bit entries, each repesenting 2MiB */
 	for (i = 0; i < 2048; i++)
 		pgtable[2048 + i * 2] = 0x183 + (i << 21UL);
 }

 int cpu_jump_to_64bit(ulong setup_base, ulong target)
 {
 	uint32_t *pgtable;

 	pgtable = memalign(4096, PAGETABLE_SIZE);
 	if (!pgtable)
 		return -ENOMEM;

 	build_pagetable(pgtable);
 	cpu_call64((ulong)pgtable, setup_base, target);
 	free(pgtable);

 	return -EFAULT;
 }

 /*
  * Jump from SPL to U-Boot
  *
  * This function is work-in-progress with many issues to resolve.
  *
  * It works by setting up several regions:
  *   ptr      - a place to put the code that jumps into 64-bit mode
  *   gdt      - a place to put the global descriptor table
  *   pgtable  - a place to put the page tables
  *
  * The cpu_call64() code is copied from ROM and then manually patched so that
  * it has the correct GDT address in RAM. U-Boot is copied from ROM into
  * its pre-relocation address. Then we jump to the cpu_call64() code in RAM,
  * which changes to 64-bit mode and starts U-Boot.
  */
 int cpu_jump_to_64bit_uboot(ulong target)
 {
 	typedef void (*func_t)(ulong pgtable, ulong setup_base, ulong target);
 	uint32_t *pgtable;
 	func_t func;

 	pgtable = (uint32_t *)PAGETABLE_BASE;

 	build_pagetable(pgtable);

 	/* TODO(sjg@chromium.org): Find a better place for this */
 	char *ptr = (char *)0x3000000;
 	char *gdt = (char *)0x3100000;

 	extern char gdt64[];

 	memcpy(ptr, cpu_call64, 0x1000);
 	memcpy(gdt, gdt64, 0x100);

 	/*
 	 * TODO(sjg@chromium.org): This manually inserts the pointers into
 	 * the code. Tidy this up to avoid this.
 	 */
 	func = (func_t)ptr;
 	ulong ofs = (ulong)cpu_call64 - (ulong)ptr;
 	*(ulong *)(ptr + 7) = (ulong)gdt;
 	*(ulong *)(ptr + 0xc) = (ulong)gdt + 2;
 	*(ulong *)(ptr + 0x13) = (ulong)gdt;
 	*(ulong *)(ptr + 0x117 - 0xd4) -= ofs;

 	/*
 	 * Copy U-Boot from ROM
 	 * TODO(sjg@chromium.org): Figure out a way to get the text base
 	 * correctly here, and in the device-tree binman definition.
 	 *
 	 * Also consider using FIT so we get the correct image length and
 	 * parameters.
 	 */
 	memcpy((char *)target, (char *)0xfff00000, 0x100000);

 	/* Jump to U-Boot */
 	func((ulong)pgtable, 0, (ulong)target);

 	return -EFAULT;
 }

 #ifdef CONFIG_SMP
 static int enable_smis(struct udevice *cpu, void *unused)
 {
 	return 0;
 }

 static struct mp_flight_record mp_steps[] = {
 	MP_FR_BLOCK_APS(mp_init_cpu, NULL, mp_init_cpu, NULL),
 	/* Wait for APs to finish initialization before proceeding */
 	MP_FR_BLOCK_APS(NULL, NULL, enable_smis, NULL),
 };

 int x86_mp_init(void)
 {
 	struct mp_params mp_params;

 	mp_params.parallel_microcode_load = 0,
 	mp_params.flight_plan = &mp_steps[0];
 	mp_params.num_records = ARRAY_SIZE(mp_steps);
 	mp_params.microcode_pointer = 0;

 	if (mp_init(&mp_params)) {
 		printf("Warning: MP init failure\n");
 		return -EIO;
 	}

 	return 0;
 }
 #endif
	// SPDX-License-Identifier: GPL-2.0+
	/*
	* (C) Copyright 2008-2011
	* Graeme Russ, <graeme.russ@gmail.com>
	*
	* (C) Copyright 2002
	* Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
	*
	* (C) Copyright 2002
	* Sysgo Real-Time Solutions, GmbH <www.elinos.com>
	* Marius Groeger <mgroeger@sysgo.de>
	*
	* (C) Copyright 2002
	* Sysgo Real-Time Solutions, GmbH <www.elinos.com>
	* Alex Zuepke <azu@sysgo.de>
	*
	* Part of this file is adapted from coreboot
	* src/arch/x86/lib/cpu.c
	*/

	#include <common.h>
	#include <malloc.h>
	#include <asm/control_regs.h>
	#include <asm/cpu.h>
	#include <asm/mp.h>
	#include <asm/msr.h>
	#include <asm/mtrr.h>
	#include <asm/processor-flags.h>

	DECLARE_GLOBAL_DATA_PTR;

	/*
	* Constructor for a conventional segment GDT (or LDT) entry
	* This is a macro so it can be used in initialisers
	*/
	#define GDT_ENTRY(flags, base, limit) \
	((((base) & 0xff000000ULL) << (56-24)) \| \
	(((flags) & 0x0000f0ffULL) << 40) \| \
	(((limit) & 0x000f0000ULL) << (48-16)) \| \
	(((base) & 0x00ffffffULL) << 16) \| \
	(((limit) & 0x0000ffffULL)))

	struct gdt_ptr {
	u16 len;
	u32 ptr;
	} __packed;

	struct cpu_device_id {
	unsigned vendor;
	unsigned device;
	};

	struct cpuinfo_x86 {
	uint8_t x86; /* CPU family */
	uint8_t x86_vendor; /* CPU vendor */
	uint8_t x86_model;
	uint8_t x86_mask;
	};

	/*
	* List of cpu vendor strings along with their normalized
	* id values.
	*/
	static const struct {
	int vendor;
	const char *name;
	} x86_vendors[] = {
	{ X86_VENDOR_INTEL, "GenuineIntel", },
	{ X86_VENDOR_CYRIX, "CyrixInstead", },
	{ X86_VENDOR_AMD, "AuthenticAMD", },
	{ X86_VENDOR_UMC, "UMC UMC UMC ", },
	{ X86_VENDOR_NEXGEN, "NexGenDriven", },
	{ X86_VENDOR_CENTAUR, "CentaurHauls", },
	{ X86_VENDOR_RISE, "RiseRiseRise", },
	{ X86_VENDOR_TRANSMETA, "GenuineTMx86", },
	{ X86_VENDOR_TRANSMETA, "TransmetaCPU", },
	{ X86_VENDOR_NSC, "Geode by NSC", },
	{ X86_VENDOR_SIS, "SiS SiS SiS ", },
	};

	static void load_ds(u32 segment)
	{
	asm volatile("movl %0, %%ds" : : "r" (segment * X86_GDT_ENTRY_SIZE));
	}

	static void load_es(u32 segment)
	{
	asm volatile("movl %0, %%es" : : "r" (segment * X86_GDT_ENTRY_SIZE));
	}

	static void load_fs(u32 segment)
	{
	asm volatile("movl %0, %%fs" : : "r" (segment * X86_GDT_ENTRY_SIZE));
	}

	static void load_gs(u32 segment)
	{
	asm volatile("movl %0, %%gs" : : "r" (segment * X86_GDT_ENTRY_SIZE));
	}

	static void load_ss(u32 segment)
	{
	asm volatile("movl %0, %%ss" : : "r" (segment * X86_GDT_ENTRY_SIZE));
	}

	static void load_gdt(const u64 *boot_gdt, u16 num_entries)
	{
	struct gdt_ptr gdt;

	gdt.len = (num_entries * X86_GDT_ENTRY_SIZE) - 1;
	gdt.ptr = (ulong)boot_gdt;

	asm volatile("lgdtl %0\n" : : "m" (gdt));
	}

	void arch_setup_gd(gd_t *new_gd)
	{
	u64 *gdt_addr;

	gdt_addr = new_gd->arch.gdt;

	/*
	* CS: code, read/execute, 4 GB, base 0
	*
	* Some OS (like VxWorks) requires GDT entry 1 to be the 32-bit CS
	*/
	gdt_addr[X86_GDT_ENTRY_UNUSED] = GDT_ENTRY(0xc09b, 0, 0xfffff);
	gdt_addr[X86_GDT_ENTRY_32BIT_CS] = GDT_ENTRY(0xc09b, 0, 0xfffff);

	/* DS: data, read/write, 4 GB, base 0 */
	gdt_addr[X86_GDT_ENTRY_32BIT_DS] = GDT_ENTRY(0xc093, 0, 0xfffff);

	/* FS: data, read/write, 4 GB, base (Global Data Pointer) */
	new_gd->arch.gd_addr = new_gd;
	gdt_addr[X86_GDT_ENTRY_32BIT_FS] = GDT_ENTRY(0xc093,
	(ulong)&new_gd->arch.gd_addr, 0xfffff);

	/* 16-bit CS: code, read/execute, 64 kB, base 0 */
	gdt_addr[X86_GDT_ENTRY_16BIT_CS] = GDT_ENTRY(0x009b, 0, 0x0ffff);

	/* 16-bit DS: data, read/write, 64 kB, base 0 */
	gdt_addr[X86_GDT_ENTRY_16BIT_DS] = GDT_ENTRY(0x0093, 0, 0x0ffff);

	gdt_addr[X86_GDT_ENTRY_16BIT_FLAT_CS] = GDT_ENTRY(0x809b, 0, 0xfffff);
	gdt_addr[X86_GDT_ENTRY_16BIT_FLAT_DS] = GDT_ENTRY(0x8093, 0, 0xfffff);

	load_gdt(gdt_addr, X86_GDT_NUM_ENTRIES);
	load_ds(X86_GDT_ENTRY_32BIT_DS);
	load_es(X86_GDT_ENTRY_32BIT_DS);
	load_gs(X86_GDT_ENTRY_32BIT_DS);
	load_ss(X86_GDT_ENTRY_32BIT_DS);
	load_fs(X86_GDT_ENTRY_32BIT_FS);
	}

	#ifdef CONFIG_HAVE_FSP
	/*
	* Setup FSP execution environment GDT
	*
	* Per Intel FSP external architecture specification, before calling any FSP
	* APIs, we need make sure the system is in flat 32-bit mode and both the code
	* and data selectors should have full 4GB access range. Here we reuse the one
	* we used in arch/x86/cpu/start16.S, and reload the segement registers.
	*/
	void setup_fsp_gdt(void)
	{
	load_gdt((const u64 *)(gdt_rom + CONFIG_RESET_SEG_START), 4);
	load_ds(X86_GDT_ENTRY_32BIT_DS);
	load_ss(X86_GDT_ENTRY_32BIT_DS);
	load_es(X86_GDT_ENTRY_32BIT_DS);
	load_fs(X86_GDT_ENTRY_32BIT_DS);
	load_gs(X86_GDT_ENTRY_32BIT_DS);
	}
	#endif

	/*
	* Cyrix CPUs without cpuid or with cpuid not yet enabled can be detected
	* by the fact that they preserve the flags across the division of 5/2.
	* PII and PPro exhibit this behavior too, but they have cpuid available.
	*/

	/*
	* Perform the Cyrix 5/2 test. A Cyrix won't change
	* the flags, while other 486 chips will.
	*/
	static inline int test_cyrix_52div(void)
	{
	unsigned int test;

	__asm__ __volatile__(
	"sahf\n\t" /* clear flags (%eax = 0x0005) */
	"div %b2\n\t" /* divide 5 by 2 */
	"lahf" /* store flags into %ah */
	: "=a" (test)
	: "0" (5), "q" (2)
	: "cc");

	/* AH is 0x02 on Cyrix after the divide.. */
	return (unsigned char) (test >> 8) == 0x02;
	}

	/*
	* Detect a NexGen CPU running without BIOS hypercode new enough
	* to have CPUID. (Thanks to Herbert Oppmann)
	*/
	static int deep_magic_nexgen_probe(void)
	{
	int ret;

	__asm__ __volatile__ (
	" movw $0x5555, %%ax\n"
	" xorw %%dx,%%dx\n"
	" movw $2, %%cx\n"
	" divw %%cx\n"
	" movl $0, %%eax\n"
	" jnz 1f\n"
	" movl $1, %%eax\n"
	"1:\n"
	: "=a" (ret) : : "cx", "dx");
	return ret;
	}

	static bool has_cpuid(void)
	{
	return flag_is_changeable_p(X86_EFLAGS_ID);
	}

	static bool has_mtrr(void)
	{
	return cpuid_edx(0x00000001) & (1 << 12) ? true : false;
	}

	static int build_vendor_name(char *vendor_name)
	{
	struct cpuid_result result;
	result = cpuid(0x00000000);
	unsigned int name_as_ints = (unsigned int )vendor_name;

	name_as_ints[0] = result.ebx;
	name_as_ints[1] = result.edx;
	name_as_ints[2] = result.ecx;

	return result.eax;
	}

	static void identify_cpu(struct cpu_device_id *cpu)
	{
	char vendor_name[16];
	int i;

	vendor_name[0] = '\0'; /* Unset */
	cpu->device = 0; /* fix gcc 4.4.4 warning */

	/* Find the id and vendor_name */
	if (!has_cpuid()) {
	/* Its a 486 if we can modify the AC flag */
	if (flag_is_changeable_p(X86_EFLAGS_AC))
	cpu->device = 0x00000400; /* 486 */
	else
	cpu->device = 0x00000300; /* 386 */
	if ((cpu->device == 0x00000400) && test_cyrix_52div()) {
	memcpy(vendor_name, "CyrixInstead", 13);
	/* If we ever care we can enable cpuid here */
	}
	/* Detect NexGen with old hypercode */
	else if (deep_magic_nexgen_probe())
	memcpy(vendor_name, "NexGenDriven", 13);
	}
	if (has_cpuid()) {
	int cpuid_level;

	cpuid_level = build_vendor_name(vendor_name);
	vendor_name[12] = '\0';

	/* Intel-defined flags: level 0x00000001 */
	if (cpuid_level >= 0x00000001) {
	cpu->device = cpuid_eax(0x00000001);
	} else {
	/* Have CPUID level 0 only unheard of */
	cpu->device = 0x00000400;
	}
	}
	cpu->vendor = X86_VENDOR_UNKNOWN;
	for (i = 0; i < ARRAY_SIZE(x86_vendors); i++) {
	if (memcmp(vendor_name, x86_vendors[i].name, 12) == 0) {
	cpu->vendor = x86_vendors[i].vendor;
	break;
	}
	}
	}

	static inline void get_fms(struct cpuinfo_x86 *c, uint32_t tfms)
	{
	c->x86 = (tfms >> 8) & 0xf;
	c->x86_model = (tfms >> 4) & 0xf;
	c->x86_mask = tfms & 0xf;
	if (c->x86 == 0xf)
	c->x86 += (tfms >> 20) & 0xff;
	if (c->x86 >= 0x6)
	c->x86_model += ((tfms >> 16) & 0xF) << 4;
	}

	u32 cpu_get_family_model(void)
	{
	return gd->arch.x86_device & 0x0fff0ff0;
	}

	u32 cpu_get_stepping(void)
	{
	return gd->arch.x86_mask;
	}

	int x86_cpu_init_f(void)
	{
	const u32 em_rst = ~X86_CR0_EM;
	const u32 mp_ne_set = X86_CR0_MP \| X86_CR0_NE;

	if (ll_boot_init()) {
	/* initialize FPU, reset EM, set MP and NE */
	asm ("fninit\n" \
	"movl %%cr0, %%eax\n" \
	"andl %0, %%eax\n" \
	"orl %1, %%eax\n" \
	"movl %%eax, %%cr0\n" \
	: : "i" (em_rst), "i" (mp_ne_set) : "eax");
	}

	/* identify CPU via cpuid and store the decoded info into gd->arch */
	if (has_cpuid()) {
	struct cpu_device_id cpu;
	struct cpuinfo_x86 c;

	identify_cpu(&cpu);
	get_fms(&c, cpu.device);
	gd->arch.x86 = c.x86;
	gd->arch.x86_vendor = cpu.vendor;
	gd->arch.x86_model = c.x86_model;
	gd->arch.x86_mask = c.x86_mask;
	gd->arch.x86_device = cpu.device;

	gd->arch.has_mtrr = has_mtrr();
	}
	/* Don't allow PCI region 3 to use memory in the 2-4GB memory hole */
	gd->pci_ram_top = 0x80000000U;

	/* Configure fixed range MTRRs for some legacy regions */
	if (gd->arch.has_mtrr) {
	u64 mtrr_cap;

	mtrr_cap = native_read_msr(MTRR_CAP_MSR);
	if (mtrr_cap & MTRR_CAP_FIX) {
	/* Mark the VGA RAM area as uncacheable */
	native_write_msr(MTRR_FIX_16K_A0000_MSR,
	MTRR_FIX_TYPE(MTRR_TYPE_UNCACHEABLE),
	MTRR_FIX_TYPE(MTRR_TYPE_UNCACHEABLE));

	/*
	* Mark the PCI ROM area as cacheable to improve ROM
	* execution performance.
	*/
	native_write_msr(MTRR_FIX_4K_C0000_MSR,
	MTRR_FIX_TYPE(MTRR_TYPE_WRBACK),
	MTRR_FIX_TYPE(MTRR_TYPE_WRBACK));
	native_write_msr(MTRR_FIX_4K_C8000_MSR,
	MTRR_FIX_TYPE(MTRR_TYPE_WRBACK),
	MTRR_FIX_TYPE(MTRR_TYPE_WRBACK));
	native_write_msr(MTRR_FIX_4K_D0000_MSR,
	MTRR_FIX_TYPE(MTRR_TYPE_WRBACK),
	MTRR_FIX_TYPE(MTRR_TYPE_WRBACK));
	native_write_msr(MTRR_FIX_4K_D8000_MSR,
	MTRR_FIX_TYPE(MTRR_TYPE_WRBACK),
	MTRR_FIX_TYPE(MTRR_TYPE_WRBACK));

	/* Enable the fixed range MTRRs */
	msr_setbits_64(MTRR_DEF_TYPE_MSR, MTRR_DEF_TYPE_FIX_EN);
	}
	}

	#ifdef CONFIG_I8254_TIMER
	/* Set up the i8254 timer if required */
	i8254_init();
	#endif

	return 0;
	}

	void x86_enable_caches(void)
	{
	unsigned long cr0;

	cr0 = read_cr0();
	cr0 &= ~(X86_CR0_NW \| X86_CR0_CD);
	write_cr0(cr0);
	wbinvd();
	}
	void enable_caches(void) __attribute__((weak, alias("x86_enable_caches")));

	void x86_disable_caches(void)
	{
	unsigned long cr0;

	cr0 = read_cr0();
	cr0 \|= X86_CR0_NW \| X86_CR0_CD;
	wbinvd();
	write_cr0(cr0);
	wbinvd();
	}
	void disable_caches(void) __attribute__((weak, alias("x86_disable_caches")));

	int dcache_status(void)
	{
	return !(read_cr0() & X86_CR0_CD);
	}

	void cpu_enable_paging_pae(ulong cr3)
	{
	__asm__ __volatile__(
	/* Load the page table address */
	"movl %0, %%cr3\n"
	/* Enable pae */
	"movl %%cr4, %%eax\n"
	"orl $0x00000020, %%eax\n"
	"movl %%eax, %%cr4\n"
	/* Enable paging */
	"movl %%cr0, %%eax\n"
	"orl $0x80000000, %%eax\n"
	"movl %%eax, %%cr0\n"
	:
	: "r" (cr3)
	: "eax");
	}

	void cpu_disable_paging_pae(void)
	{
	/* Turn off paging */
	__asm__ __volatile__ (
	/* Disable paging */
	"movl %%cr0, %%eax\n"
	"andl $0x7fffffff, %%eax\n"
	"movl %%eax, %%cr0\n"
	/* Disable pae */
	"movl %%cr4, %%eax\n"
	"andl $0xffffffdf, %%eax\n"
	"movl %%eax, %%cr4\n"
	:
	:
	: "eax");
	}

	static bool can_detect_long_mode(void)
	{
	return cpuid_eax(0x80000000) > 0x80000000UL;
	}

	static bool has_long_mode(void)
	{
	return cpuid_edx(0x80000001) & (1 << 29) ? true : false;
	}

	int cpu_has_64bit(void)
	{
	return has_cpuid() && can_detect_long_mode() &&
	has_long_mode();
	}

	#define PAGETABLE_BASE 0x80000
	#define PAGETABLE_SIZE (6 * 4096)

	/**
	* build_pagetable() - build a flat 4GiB page table structure for 64-bti mode
	*
	* @pgtable: Pointer to a 24iKB block of memory
	*/
	static void build_pagetable(uint32_t *pgtable)
	{
	uint i;

	memset(pgtable, '\0', PAGETABLE_SIZE);

	/* Level 4 needs a single entry */
	pgtable[0] = (ulong)&pgtable[1024] + 7;

	/* Level 3 has one 64-bit entry for each GiB of memory */
	for (i = 0; i < 4; i++)
	pgtable[1024 + i * 2] = (ulong)&pgtable[2048] + 0x1000 * i + 7;

	/* Level 2 has 2048 64-bit entries, each repesenting 2MiB */
	for (i = 0; i < 2048; i++)
	pgtable[2048 + i * 2] = 0x183 + (i << 21UL);
	}

	int cpu_jump_to_64bit(ulong setup_base, ulong target)
	{
	uint32_t *pgtable;

	pgtable = memalign(4096, PAGETABLE_SIZE);
	if (!pgtable)
	return -ENOMEM;

	build_pagetable(pgtable);
	cpu_call64((ulong)pgtable, setup_base, target);
	free(pgtable);

	return -EFAULT;
	}

	/*
	* Jump from SPL to U-Boot
	*
	* This function is work-in-progress with many issues to resolve.
	*
	* It works by setting up several regions:
	* ptr - a place to put the code that jumps into 64-bit mode
	* gdt - a place to put the global descriptor table
	* pgtable - a place to put the page tables
	*
	* The cpu_call64() code is copied from ROM and then manually patched so that
	* it has the correct GDT address in RAM. U-Boot is copied from ROM into
	* its pre-relocation address. Then we jump to the cpu_call64() code in RAM,
	* which changes to 64-bit mode and starts U-Boot.
	*/
	int cpu_jump_to_64bit_uboot(ulong target)
	{
	typedef void (*func_t)(ulong pgtable, ulong setup_base, ulong target);
	uint32_t *pgtable;
	func_t func;

	pgtable = (uint32_t *)PAGETABLE_BASE;

	build_pagetable(pgtable);

	/* TODO(sjg@chromium.org): Find a better place for this */
	char ptr = (char )0x3000000;
	char gdt = (char )0x3100000;

	extern char gdt64[];

	memcpy(ptr, cpu_call64, 0x1000);
	memcpy(gdt, gdt64, 0x100);

	/*
	* TODO(sjg@chromium.org): This manually inserts the pointers into
	* the code. Tidy this up to avoid this.
	*/
	func = (func_t)ptr;
	ulong ofs = (ulong)cpu_call64 - (ulong)ptr;
	(ulong )(ptr + 7) = (ulong)gdt;
	(ulong )(ptr + 0xc) = (ulong)gdt + 2;
	(ulong )(ptr + 0x13) = (ulong)gdt;
	(ulong )(ptr + 0x117 - 0xd4) -= ofs;

	/*
	* Copy U-Boot from ROM
	* TODO(sjg@chromium.org): Figure out a way to get the text base
	* correctly here, and in the device-tree binman definition.
	*
	* Also consider using FIT so we get the correct image length and
	* parameters.
	*/
	memcpy((char )target, (char )0xfff00000, 0x100000);

	/* Jump to U-Boot */
	func((ulong)pgtable, 0, (ulong)target);

	return -EFAULT;
	}

	#ifdef CONFIG_SMP
	static int enable_smis(struct udevice cpu, void unused)
	{
	return 0;
	}

	static struct mp_flight_record mp_steps[] = {
	MP_FR_BLOCK_APS(mp_init_cpu, NULL, mp_init_cpu, NULL),
	/* Wait for APs to finish initialization before proceeding */
	MP_FR_BLOCK_APS(NULL, NULL, enable_smis, NULL),
	};

	int x86_mp_init(void)
	{
	struct mp_params mp_params;

	mp_params.parallel_microcode_load = 0,
	mp_params.flight_plan = &mp_steps[0];
	mp_params.num_records = ARRAY_SIZE(mp_steps);
	mp_params.microcode_pointer = 0;

	if (mp_init(&mp_params)) {
	printf("Warning: MP init failure\n");
	return -EIO;
	}

	return 0;
	}
	#endif