xref: /openbmc/linux/arch/x86/kernel/cpu/centaur.c (revision 93f5715e)
1 // SPDX-License-Identifier: GPL-2.0
2 
3 #include <linux/sched.h>
4 #include <linux/sched/clock.h>
5 
6 #include <asm/cpufeature.h>
7 #include <asm/e820/api.h>
8 #include <asm/mtrr.h>
9 #include <asm/msr.h>
10 
11 #include "cpu.h"
12 
13 #define ACE_PRESENT	(1 << 6)
14 #define ACE_ENABLED	(1 << 7)
15 #define ACE_FCR		(1 << 28)	/* MSR_VIA_FCR */
16 
17 #define RNG_PRESENT	(1 << 2)
18 #define RNG_ENABLED	(1 << 3)
19 #define RNG_ENABLE	(1 << 6)	/* MSR_VIA_RNG */
20 
21 #define X86_VMX_FEATURE_PROC_CTLS_TPR_SHADOW	0x00200000
22 #define X86_VMX_FEATURE_PROC_CTLS_VNMI		0x00400000
23 #define X86_VMX_FEATURE_PROC_CTLS_2ND_CTLS	0x80000000
24 #define X86_VMX_FEATURE_PROC_CTLS2_VIRT_APIC	0x00000001
25 #define X86_VMX_FEATURE_PROC_CTLS2_EPT		0x00000002
26 #define X86_VMX_FEATURE_PROC_CTLS2_VPID		0x00000020
27 
28 static void init_c3(struct cpuinfo_x86 *c)
29 {
30 	u32  lo, hi;
31 
32 	/* Test for Centaur Extended Feature Flags presence */
33 	if (cpuid_eax(0xC0000000) >= 0xC0000001) {
34 		u32 tmp = cpuid_edx(0xC0000001);
35 
36 		/* enable ACE unit, if present and disabled */
37 		if ((tmp & (ACE_PRESENT | ACE_ENABLED)) == ACE_PRESENT) {
38 			rdmsr(MSR_VIA_FCR, lo, hi);
39 			lo |= ACE_FCR;		/* enable ACE unit */
40 			wrmsr(MSR_VIA_FCR, lo, hi);
41 			pr_info("CPU: Enabled ACE h/w crypto\n");
42 		}
43 
44 		/* enable RNG unit, if present and disabled */
45 		if ((tmp & (RNG_PRESENT | RNG_ENABLED)) == RNG_PRESENT) {
46 			rdmsr(MSR_VIA_RNG, lo, hi);
47 			lo |= RNG_ENABLE;	/* enable RNG unit */
48 			wrmsr(MSR_VIA_RNG, lo, hi);
49 			pr_info("CPU: Enabled h/w RNG\n");
50 		}
51 
52 		/* store Centaur Extended Feature Flags as
53 		 * word 5 of the CPU capability bit array
54 		 */
55 		c->x86_capability[CPUID_C000_0001_EDX] = cpuid_edx(0xC0000001);
56 	}
57 #ifdef CONFIG_X86_32
58 	/* Cyrix III family needs CX8 & PGE explicitly enabled. */
59 	if (c->x86_model >= 6 && c->x86_model <= 13) {
60 		rdmsr(MSR_VIA_FCR, lo, hi);
61 		lo |= (1<<1 | 1<<7);
62 		wrmsr(MSR_VIA_FCR, lo, hi);
63 		set_cpu_cap(c, X86_FEATURE_CX8);
64 	}
65 
66 	/* Before Nehemiah, the C3's had 3dNOW! */
67 	if (c->x86_model >= 6 && c->x86_model < 9)
68 		set_cpu_cap(c, X86_FEATURE_3DNOW);
69 #endif
70 	if (c->x86 == 0x6 && c->x86_model >= 0xf) {
71 		c->x86_cache_alignment = c->x86_clflush_size * 2;
72 		set_cpu_cap(c, X86_FEATURE_REP_GOOD);
73 	}
74 
75 	cpu_detect_cache_sizes(c);
76 }
77 
78 enum {
79 		ECX8		= 1<<1,
80 		EIERRINT	= 1<<2,
81 		DPM		= 1<<3,
82 		DMCE		= 1<<4,
83 		DSTPCLK		= 1<<5,
84 		ELINEAR		= 1<<6,
85 		DSMC		= 1<<7,
86 		DTLOCK		= 1<<8,
87 		EDCTLB		= 1<<8,
88 		EMMX		= 1<<9,
89 		DPDC		= 1<<11,
90 		EBRPRED		= 1<<12,
91 		DIC		= 1<<13,
92 		DDC		= 1<<14,
93 		DNA		= 1<<15,
94 		ERETSTK		= 1<<16,
95 		E2MMX		= 1<<19,
96 		EAMD3D		= 1<<20,
97 };
98 
99 static void early_init_centaur(struct cpuinfo_x86 *c)
100 {
101 	switch (c->x86) {
102 #ifdef CONFIG_X86_32
103 	case 5:
104 		/* Emulate MTRRs using Centaur's MCR. */
105 		set_cpu_cap(c, X86_FEATURE_CENTAUR_MCR);
106 		break;
107 #endif
108 	case 6:
109 		if (c->x86_model >= 0xf)
110 			set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
111 		break;
112 	}
113 #ifdef CONFIG_X86_64
114 	set_cpu_cap(c, X86_FEATURE_SYSENTER32);
115 #endif
116 	if (c->x86_power & (1 << 8)) {
117 		set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
118 		set_cpu_cap(c, X86_FEATURE_NONSTOP_TSC);
119 	}
120 }
121 
122 static void centaur_detect_vmx_virtcap(struct cpuinfo_x86 *c)
123 {
124 	u32 vmx_msr_low, vmx_msr_high, msr_ctl, msr_ctl2;
125 
126 	rdmsr(MSR_IA32_VMX_PROCBASED_CTLS, vmx_msr_low, vmx_msr_high);
127 	msr_ctl = vmx_msr_high | vmx_msr_low;
128 
129 	if (msr_ctl & X86_VMX_FEATURE_PROC_CTLS_TPR_SHADOW)
130 		set_cpu_cap(c, X86_FEATURE_TPR_SHADOW);
131 	if (msr_ctl & X86_VMX_FEATURE_PROC_CTLS_VNMI)
132 		set_cpu_cap(c, X86_FEATURE_VNMI);
133 	if (msr_ctl & X86_VMX_FEATURE_PROC_CTLS_2ND_CTLS) {
134 		rdmsr(MSR_IA32_VMX_PROCBASED_CTLS2,
135 		      vmx_msr_low, vmx_msr_high);
136 		msr_ctl2 = vmx_msr_high | vmx_msr_low;
137 		if ((msr_ctl2 & X86_VMX_FEATURE_PROC_CTLS2_VIRT_APIC) &&
138 		    (msr_ctl & X86_VMX_FEATURE_PROC_CTLS_TPR_SHADOW))
139 			set_cpu_cap(c, X86_FEATURE_FLEXPRIORITY);
140 		if (msr_ctl2 & X86_VMX_FEATURE_PROC_CTLS2_EPT)
141 			set_cpu_cap(c, X86_FEATURE_EPT);
142 		if (msr_ctl2 & X86_VMX_FEATURE_PROC_CTLS2_VPID)
143 			set_cpu_cap(c, X86_FEATURE_VPID);
144 	}
145 }
146 
147 static void init_centaur(struct cpuinfo_x86 *c)
148 {
149 #ifdef CONFIG_X86_32
150 	char *name;
151 	u32  fcr_set = 0;
152 	u32  fcr_clr = 0;
153 	u32  lo, hi, newlo;
154 	u32  aa, bb, cc, dd;
155 
156 	/*
157 	 * Bit 31 in normal CPUID used for nonstandard 3DNow ID;
158 	 * 3DNow is IDd by bit 31 in extended CPUID (1*32+31) anyway
159 	 */
160 	clear_cpu_cap(c, 0*32+31);
161 #endif
162 	early_init_centaur(c);
163 	init_intel_cacheinfo(c);
164 	detect_num_cpu_cores(c);
165 #ifdef CONFIG_X86_32
166 	detect_ht(c);
167 #endif
168 
169 	if (c->cpuid_level > 9) {
170 		unsigned int eax = cpuid_eax(10);
171 
172 		/*
173 		 * Check for version and the number of counters
174 		 * Version(eax[7:0]) can't be 0;
175 		 * Counters(eax[15:8]) should be greater than 1;
176 		 */
177 		if ((eax & 0xff) && (((eax >> 8) & 0xff) > 1))
178 			set_cpu_cap(c, X86_FEATURE_ARCH_PERFMON);
179 	}
180 
181 	switch (c->x86) {
182 #ifdef CONFIG_X86_32
183 	case 5:
184 		switch (c->x86_model) {
185 		case 4:
186 			name = "C6";
187 			fcr_set = ECX8|DSMC|EDCTLB|EMMX|ERETSTK;
188 			fcr_clr = DPDC;
189 			pr_notice("Disabling bugged TSC.\n");
190 			clear_cpu_cap(c, X86_FEATURE_TSC);
191 			break;
192 		case 8:
193 			switch (c->x86_stepping) {
194 			default:
195 			name = "2";
196 				break;
197 			case 7 ... 9:
198 				name = "2A";
199 				break;
200 			case 10 ... 15:
201 				name = "2B";
202 				break;
203 			}
204 			fcr_set = ECX8|DSMC|DTLOCK|EMMX|EBRPRED|ERETSTK|
205 				  E2MMX|EAMD3D;
206 			fcr_clr = DPDC;
207 			break;
208 		case 9:
209 			name = "3";
210 			fcr_set = ECX8|DSMC|DTLOCK|EMMX|EBRPRED|ERETSTK|
211 				  E2MMX|EAMD3D;
212 			fcr_clr = DPDC;
213 			break;
214 		default:
215 			name = "??";
216 		}
217 
218 		rdmsr(MSR_IDT_FCR1, lo, hi);
219 		newlo = (lo|fcr_set) & (~fcr_clr);
220 
221 		if (newlo != lo) {
222 			pr_info("Centaur FCR was 0x%X now 0x%X\n",
223 				lo, newlo);
224 			wrmsr(MSR_IDT_FCR1, newlo, hi);
225 		} else {
226 			pr_info("Centaur FCR is 0x%X\n", lo);
227 		}
228 		/* Emulate MTRRs using Centaur's MCR. */
229 		set_cpu_cap(c, X86_FEATURE_CENTAUR_MCR);
230 		/* Report CX8 */
231 		set_cpu_cap(c, X86_FEATURE_CX8);
232 		/* Set 3DNow! on Winchip 2 and above. */
233 		if (c->x86_model >= 8)
234 			set_cpu_cap(c, X86_FEATURE_3DNOW);
235 		/* See if we can find out some more. */
236 		if (cpuid_eax(0x80000000) >= 0x80000005) {
237 			/* Yes, we can. */
238 			cpuid(0x80000005, &aa, &bb, &cc, &dd);
239 			/* Add L1 data and code cache sizes. */
240 			c->x86_cache_size = (cc>>24)+(dd>>24);
241 		}
242 		sprintf(c->x86_model_id, "WinChip %s", name);
243 		break;
244 #endif
245 	case 6:
246 		init_c3(c);
247 		break;
248 	}
249 #ifdef CONFIG_X86_64
250 	set_cpu_cap(c, X86_FEATURE_LFENCE_RDTSC);
251 #endif
252 
253 	if (cpu_has(c, X86_FEATURE_VMX))
254 		centaur_detect_vmx_virtcap(c);
255 }
256 
257 #ifdef CONFIG_X86_32
258 static unsigned int
259 centaur_size_cache(struct cpuinfo_x86 *c, unsigned int size)
260 {
261 	/* VIA C3 CPUs (670-68F) need further shifting. */
262 	if ((c->x86 == 6) && ((c->x86_model == 7) || (c->x86_model == 8)))
263 		size >>= 8;
264 
265 	/*
266 	 * There's also an erratum in Nehemiah stepping 1, which
267 	 * returns '65KB' instead of '64KB'
268 	 *  - Note, it seems this may only be in engineering samples.
269 	 */
270 	if ((c->x86 == 6) && (c->x86_model == 9) &&
271 				(c->x86_stepping == 1) && (size == 65))
272 		size -= 1;
273 	return size;
274 }
275 #endif
276 
277 static const struct cpu_dev centaur_cpu_dev = {
278 	.c_vendor	= "Centaur",
279 	.c_ident	= { "CentaurHauls" },
280 	.c_early_init	= early_init_centaur,
281 	.c_init		= init_centaur,
282 #ifdef CONFIG_X86_32
283 	.legacy_cache_size = centaur_size_cache,
284 #endif
285 	.c_x86_vendor	= X86_VENDOR_CENTAUR,
286 };
287 
288 cpu_dev_register(centaur_cpu_dev);
289