C++ cpuid_count函数代码示例

/*
 * Enable and initialize the xsave feature.
 */
void __ref xsave_cntxt_init(void)
{
	unsigned int eax, ebx, ecx, edx;

	cpuid_count(0xd, 0, &eax, &ebx, &ecx, &edx);
	pcntxt_mask = eax + ((u64)edx << 32);

	if ((pcntxt_mask & XSTATE_FPSSE) != XSTATE_FPSSE) {
		printk(KERN_ERR "FP/SSE not shown under xsave features 0x%llx\n",
		       pcntxt_mask);
		BUG();
	}

	/*
	 * Support only the state known to OS.
	 */
	pcntxt_mask = pcntxt_mask & XCNTXT_MASK;
	xsave_init();

	/*
	 * Recompute the context size for enabled features
	 */
	cpuid_count(0xd, 0, &eax, &ebx, &ecx, &edx);
	xstate_size = ebx;

	prepare_fx_sw_frame();

	setup_xstate_init();

	printk(KERN_INFO "xsave/xrstor: enabled xstate_bv 0x%llx, "
	       "cntxt size 0x%x\n",
	       pcntxt_mask, xstate_size);
}

/*
 * Calculate total size of enabled xstates in XCR0/xfeatures_mask.
 *
 * Note the SDM's wording here.  "sub-function 0" only enumerates
 * the size of the *user* states.  If we use it to size a buffer
 * that we use 'XSAVES' on, we could potentially overflow the
 * buffer because 'XSAVES' saves system states too.
 *
 * Note that we do not currently set any bits on IA32_XSS so
 * 'XCR0 | IA32_XSS == XCR0' for now.
 */
static unsigned int __init calculate_xstate_size(void)
{
	unsigned int eax, ebx, ecx, edx;
	unsigned int calculated_xstate_size;

	if (!cpu_has_xsaves) {
		/*
		 * - CPUID function 0DH, sub-function 0:
		 *    EBX enumerates the size (in bytes) required by
		 *    the XSAVE instruction for an XSAVE area
		 *    containing all the *user* state components
		 *    corresponding to bits currently set in XCR0.
		 */
		cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
		calculated_xstate_size = ebx;
	} else {
		/*
		 * - CPUID function 0DH, sub-function 1:
		 *    EBX enumerates the size (in bytes) required by
		 *    the XSAVES instruction for an XSAVE area
		 *    containing all the state components
		 *    corresponding to bits currently set in
		 *    XCR0 | IA32_XSS.
		 */
		cpuid_count(XSTATE_CPUID, 1, &eax, &ebx, &ecx, &edx);
		calculated_xstate_size = ebx;
	}
	return calculated_xstate_size;
}

/*
 * Actually perform cpuid operation.
 */
static int
cpuctl_do_cpuid_count(int cpu, cpuctl_cpuid_count_args_t *data,
    struct thread *td)
{
	int is_bound = 0;
	int oldcpu;

	KASSERT(cpu >= 0 && cpu <= mp_maxid,
	    ("[cpuctl,%d]: bad cpu number %d", __LINE__, cpu));

	/* Explicitly clear cpuid data to avoid returning stale info. */
	bzero(data->data, sizeof(data->data));
	DPRINTF("[cpuctl,%d]: retrieving cpuid lev %#0x type %#0x for %d cpu\n",
	    __LINE__, data->level, data->level_type, cpu);
#ifdef __i386__
	if (cpu_id == 0)
		return (ENODEV);
#endif
	oldcpu = td->td_oncpu;
	is_bound = cpu_sched_is_bound(td);
	set_cpu(cpu, td);
	cpuid_count(data->level, data->level_type, data->data);
	restore_cpu(oldcpu, is_bound, td);
	return (0);
}

/*
 * Record the offsets and sizes of various xstates contained
 * in the XSAVE state memory layout.
 */
static void __init setup_xstate_features(void)
{
	u32 eax, ebx, ecx, edx, i;
	/* start at the beginnning of the "extended state" */
	unsigned int last_good_offset = offsetof(struct xregs_state,
						 extended_state_area);

	for (i = FIRST_EXTENDED_XFEATURE; i < XFEATURE_MAX; i++) {
		if (!xfeature_enabled(i))
			continue;

		cpuid_count(XSTATE_CPUID, i, &eax, &ebx, &ecx, &edx);
		xstate_offsets[i] = ebx;
		xstate_sizes[i] = eax;
		/*
		 * In our xstate size checks, we assume that the
		 * highest-numbered xstate feature has the
		 * highest offset in the buffer.  Ensure it does.
		 */
		WARN_ONCE(last_good_offset > xstate_offsets[i],
			"x86/fpu: misordered xstate at %d\n", last_good_offset);
		last_good_offset = xstate_offsets[i];

		printk(KERN_INFO "x86/fpu: xstate_offset[%d]: %4d, xstate_sizes[%d]: %4d\n", i, ebx, i, eax);
	}
}

int main(int argc, char *argv[])
{
    uint32_t leaf, counter;
    uint32_t eax, ebx, ecx, edx;

    openconsole(&dev_null_r, &dev_stdcon_w);

    if (argc < 2 || argc > 4) {
	printf("Usage: %s leaf [counter]\n", argv[0]);
	exit(1);
    }

    leaf = strtoul(argv[1], NULL, 0);
    counter = (argv > 2) ? strtoul(argv[2], NULL, 0) : 0;

    if (!cpu_has_eflag(EFLAGS_ID)) {
	printf("The CPUID instruction is not supported\n");
	exit(1);
    }

    cpuid_count(leaf, counter, &eax, &ebx, &ecx, &edx);

    dump_reg("eax", eax);
    dump_reg("ebx", ebx);
    dump_reg("ecx", ecx);
    dump_reg("edx", edx);

    return 0;
}

int detect_extended_topology_early(struct cpuinfo_x86 *c)
{
#ifdef CONFIG_SMP
	unsigned int eax, ebx, ecx, edx;

	if (c->cpuid_level < 0xb)
		return -1;

	cpuid_count(0xb, SMT_LEVEL, &eax, &ebx, &ecx, &edx);

	/*
	 * check if the cpuid leaf 0xb is actually implemented.
	 */
	if (ebx == 0 || (LEAFB_SUBTYPE(ecx) != SMT_TYPE))
		return -1;

	set_cpu_cap(c, X86_FEATURE_XTOPOLOGY);

	/*
	 * initial apic id, which also represents 32-bit extended x2apic id.
	 */
	c->initial_apicid = edx;
	smp_num_siblings = LEVEL_MAX_SIBLINGS(ebx);
#endif
	return 0;
}

/*
 * Check for extended topology enumeration cpuid leaf 0xb and if it
 * exists, use it for populating initial_apicid and cpu topology
 * detection.
 */
int detect_extended_topology(struct cpuinfo_x86 *c)
{
#ifdef CONFIG_SMP
	unsigned int eax, ebx, ecx, edx, sub_index;
	unsigned int ht_mask_width, core_plus_mask_width;
	unsigned int core_select_mask, core_level_siblings;

	if (detect_extended_topology_early(c) < 0)
		return -1;

	/*
	 * Populate HT related information from sub-leaf level 0.
	 */
	cpuid_count(0xb, SMT_LEVEL, &eax, &ebx, &ecx, &edx);
	core_level_siblings = smp_num_siblings = LEVEL_MAX_SIBLINGS(ebx);
	core_plus_mask_width = ht_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);

	sub_index = 1;
	do {
		cpuid_count(0xb, sub_index, &eax, &ebx, &ecx, &edx);

		/*
		 * Check for the Core type in the implemented sub leaves.
		 */
		if (LEAFB_SUBTYPE(ecx) == CORE_TYPE) {
			core_level_siblings = LEVEL_MAX_SIBLINGS(ebx);
			core_plus_mask_width = BITS_SHIFT_NEXT_LEVEL(eax);
			break;
		}

		sub_index++;
	} while (LEAFB_SUBTYPE(ecx) != INVALID_TYPE);

	core_select_mask = (~(-1 << core_plus_mask_width)) >> ht_mask_width;

	c->cpu_core_id = apic->phys_pkg_id(c->initial_apicid, ht_mask_width)
						 & core_select_mask;
	c->phys_proc_id = apic->phys_pkg_id(c->initial_apicid, core_plus_mask_width);
	/*
	 * Reinit the apicid, now that we have extended initial_apicid.
	 */
	c->apicid = apic->phys_pkg_id(c->initial_apicid, 0);

	c->x86_max_cores = (core_level_siblings / smp_num_siblings);
#endif
	return 0;
}

static int xfeature_size(int xfeature_nr)
{
	u32 eax, ebx, ecx, edx;

	CHECK_XFEATURE(xfeature_nr);
	cpuid_count(XSTATE_CPUID, xfeature_nr, &eax, &ebx, &ecx, &edx);
	return eax;
}

static int xfeature_uncompacted_offset(int xfeature_nr)
{
	u32 eax, ebx, ecx, edx;

	CHECK_XFEATURE(xfeature_nr);
	cpuid_count(XSTATE_CPUID, xfeature_nr, &eax, &ebx, &ecx, &edx);
	return ebx;
}

static void do_cpuid_1_ent(struct kvm_cpuid_entry2 *entry, u32 function,
			   u32 index)
{
	entry->function = function;
	entry->index = index;
	cpuid_count(entry->function, entry->index,
		    &entry->eax, &entry->ebx, &entry->ecx, &entry->edx);
	entry->flags = 0;
}

void kvm_xstate_size_init(void)
{
	unsigned int eax, ebx, ecx, edx;

	/*  kvm only uses xstate_size if xsave is supported */
	if (cpu_has_xsave) {
		cpuid_count(0xd, 0, &eax, &ebx, &ecx, &edx);
		kvm_xstate_size = ebx;
	}
}

/*
 * Calculate total size of enabled xstates in XCR0/xfeatures_mask.
 */
static void __init init_xstate_size(void)
{
	unsigned int eax, ebx, ecx, edx;
	int i;

	if (!cpu_has_xsaves) {
		cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
		xstate_size = ebx;
		return;
	}

	xstate_size = FXSAVE_SIZE + XSAVE_HDR_SIZE;
	for (i = 2; i < 64; i++) {
		if (test_bit(i, (unsigned long *)&xfeatures_mask)) {
			cpuid_count(XSTATE_CPUID, i, &eax, &ebx, &ecx, &edx);
			xstate_size += eax;
		}
	}
}

void vmmr0_xstate_size_init(void)
{
	unsigned int eax, ebx, ecx, edx;

	/*  vmmr0 only uses xstate_size if xsave is supported */
	if (cpu_has_xsave) {
		cpuid_count(0xd, 0, &eax, &ebx, &ecx, &edx);
		vmmr0_xstate_size = ebx;
		BUG_ON(vmmr0_xstate_size > sizeof(union vmmr0_thread_xstate));
	}
}

/*
 * Enable and initialize the xsave feature.
 */
static void __init xstate_enable_boot_cpu(void)
{
	unsigned int eax, ebx, ecx, edx;

	if (boot_cpu_data.cpuid_level < XSTATE_CPUID) {
		WARN(1, KERN_ERR "XSTATE_CPUID missing\n");
		return;
	}

	cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
	pcntxt_mask = eax + ((u64)edx << 32);

	if ((pcntxt_mask & XSTATE_FPSSE) != XSTATE_FPSSE) {
		printk(KERN_ERR "FP/SSE not shown under xsave features 0x%llx\n",
		       pcntxt_mask);
		BUG();
	}

	/*
	 * Support only the state known to OS.
	 */
	pcntxt_mask = pcntxt_mask & XCNTXT_MASK;

	xstate_enable();

	/*
	 * Recompute the context size for enabled features
	 */
	cpuid_count(XSTATE_CPUID, 0, &eax, &ebx, &ecx, &edx);
	xstate_size = ebx;

	update_regset_xstate_info(xstate_size, pcntxt_mask);
	prepare_fx_sw_frame();

	setup_xstate_init();

	printk(KERN_INFO "xsave/xrstor: enabled xstate_bv 0x%llx, "
	       "cntxt size 0x%x\n",
	       pcntxt_mask, xstate_size);
}

/*
 * We could cache this like xstate_size[], but we only use
 * it here, so it would be a waste of space.
 */
static int xfeature_is_aligned(int xfeature_nr)
{
	u32 eax, ebx, ecx, edx;

	CHECK_XFEATURE(xfeature_nr);
	cpuid_count(XSTATE_CPUID, xfeature_nr, &eax, &ebx, &ecx, &edx);
	/*
	 * The value returned by ECX[1] indicates the alignment
	 * of state component i when the compacted format
	 * of the extended region of an XSAVE area is used
	 */
	return !!(ecx & 2);
}