1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * Intel PCONFIG instruction support.
 4 *
 5 * Copyright (C) 2017 Intel Corporation
 6 *
 7 * Author:
 8 *	Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
 9 */
10
11#include <asm/cpufeature.h>
12#include <asm/intel_pconfig.h>
13
14#define	PCONFIG_CPUID			0x1b
15
16#define PCONFIG_CPUID_SUBLEAF_MASK	((1 << 12) - 1)
17
18/* Subleaf type (EAX) for PCONFIG CPUID leaf (0x1B) */
19enum {
20	PCONFIG_CPUID_SUBLEAF_INVALID	= 0,
21	PCONFIG_CPUID_SUBLEAF_TARGETID	= 1,
22};
23
24/* Bitmask of supported targets */
25static u64 targets_supported __read_mostly;
26
27int pconfig_target_supported(enum pconfig_target target)
28{
29	/*
30	 * We would need to re-think the implementation once we get > 64
31	 * PCONFIG targets. Spec allows up to 2^32 targets.
32	 */
33	BUILD_BUG_ON(PCONFIG_TARGET_NR >= 64);
34
35	if (WARN_ON_ONCE(target >= 64))
36		return 0;
37	return targets_supported & (1ULL << target);
38}
39
40static int __init intel_pconfig_init(void)
41{
42	int subleaf;
43
44	if (!boot_cpu_has(X86_FEATURE_PCONFIG))
45		return 0;
46
47	/*
48	 * Scan subleafs of PCONFIG CPUID leaf.
49	 *
50	 * Subleafs of the same type need not to be consecutive.
51	 *
52	 * Stop on the first invalid subleaf type. All subleafs after the first
53	 * invalid are invalid too.
54	 */
55	for (subleaf = 0; subleaf < INT_MAX; subleaf++) {
56		struct cpuid_regs regs;
57
58		cpuid_count(PCONFIG_CPUID, subleaf,
59				&regs.eax, &regs.ebx, &regs.ecx, &regs.edx);
60
61		switch (regs.eax & PCONFIG_CPUID_SUBLEAF_MASK) {
62		case PCONFIG_CPUID_SUBLEAF_INVALID:
63			/* Stop on the first invalid subleaf */
64			goto out;
65		case PCONFIG_CPUID_SUBLEAF_TARGETID:
66			/* Mark supported PCONFIG targets */
67			if (regs.ebx < 64)
68				targets_supported |= (1ULL << regs.ebx);
69			if (regs.ecx < 64)
70				targets_supported |= (1ULL << regs.ecx);
71			if (regs.edx < 64)
72				targets_supported |= (1ULL << regs.edx);
73			break;
74		default:
75			/* Unknown CPUID.PCONFIG subleaf: ignore */
76			break;
77		}
78	}
79out:
80	return 0;
81}
82arch_initcall(intel_pconfig_init);

 1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * Intel PCONFIG instruction support.
 4 *
 5 * Copyright (C) 2017 Intel Corporation
 6 *
 7 * Author:
 8 *	Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
 9 */
10
11#include <asm/cpufeature.h>
12#include <asm/intel_pconfig.h>
13
14#define	PCONFIG_CPUID			0x1b
15
16#define PCONFIG_CPUID_SUBLEAF_MASK	((1 << 12) - 1)
17
18/* Subleaf type (EAX) for PCONFIG CPUID leaf (0x1B) */
19enum {
20	PCONFIG_CPUID_SUBLEAF_INVALID	= 0,
21	PCONFIG_CPUID_SUBLEAF_TARGETID	= 1,
22};
23
24/* Bitmask of supported targets */
25static u64 targets_supported __read_mostly;
26
27int pconfig_target_supported(enum pconfig_target target)
28{
29	/*
30	 * We would need to re-think the implementation once we get > 64
31	 * PCONFIG targets. Spec allows up to 2^32 targets.
32	 */
33	BUILD_BUG_ON(PCONFIG_TARGET_NR >= 64);
34
35	if (WARN_ON_ONCE(target >= 64))
36		return 0;
37	return targets_supported & (1ULL << target);
38}
39
40static int __init intel_pconfig_init(void)
41{
42	int subleaf;
43
44	if (!boot_cpu_has(X86_FEATURE_PCONFIG))
45		return 0;
46
47	/*
48	 * Scan subleafs of PCONFIG CPUID leaf.
49	 *
50	 * Subleafs of the same type need not to be consecutive.
51	 *
52	 * Stop on the first invalid subleaf type. All subleafs after the first
53	 * invalid are invalid too.
54	 */
55	for (subleaf = 0; subleaf < INT_MAX; subleaf++) {
56		struct cpuid_regs regs;
57
58		cpuid_count(PCONFIG_CPUID, subleaf,
59				&regs.eax, &regs.ebx, &regs.ecx, &regs.edx);
60
61		switch (regs.eax & PCONFIG_CPUID_SUBLEAF_MASK) {
62		case PCONFIG_CPUID_SUBLEAF_INVALID:
63			/* Stop on the first invalid subleaf */
64			goto out;
65		case PCONFIG_CPUID_SUBLEAF_TARGETID:
66			/* Mark supported PCONFIG targets */
67			if (regs.ebx < 64)
68				targets_supported |= (1ULL << regs.ebx);
69			if (regs.ecx < 64)
70				targets_supported |= (1ULL << regs.ecx);
71			if (regs.edx < 64)
72				targets_supported |= (1ULL << regs.edx);
73			break;
74		default:
75			/* Unknown CPUID.PCONFIG subleaf: ignore */
76			break;
77		}
78	}
79out:
80	return 0;
81}
82arch_initcall(intel_pconfig_init);