1// SPDX-License-Identifier: GPL-2.0
2
3#include <linux/sched.h>
4#include <linux/sched/clock.h>
5
6#include <asm/cpu.h>
7#include <asm/cpufeature.h>
8#include <asm/e820/api.h>
9#include <asm/mtrr.h>
10#include <asm/msr.h>
11
12#include "cpu.h"
13
14#define ACE_PRESENT (1 << 6)
15#define ACE_ENABLED (1 << 7)
16#define ACE_FCR (1 << 28) /* MSR_VIA_FCR */
17
18#define RNG_PRESENT (1 << 2)
19#define RNG_ENABLED (1 << 3)
20#define RNG_ENABLE (1 << 6) /* MSR_VIA_RNG */
21
22static void init_c3(struct cpuinfo_x86 *c)
23{
24 u32 lo, hi;
25
26 /* Test for Centaur Extended Feature Flags presence */
27 if (cpuid_eax(op: 0xC0000000) >= 0xC0000001) {
28 u32 tmp = cpuid_edx(op: 0xC0000001);
29
30 /* enable ACE unit, if present and disabled */
31 if ((tmp & (ACE_PRESENT | ACE_ENABLED)) == ACE_PRESENT) {
32 rdmsr(MSR_VIA_FCR, lo, hi);
33 lo |= ACE_FCR; /* enable ACE unit */
34 wrmsr(MSR_VIA_FCR, low: lo, high: hi);
35 pr_info("CPU: Enabled ACE h/w crypto\n");
36 }
37
38 /* enable RNG unit, if present and disabled */
39 if ((tmp & (RNG_PRESENT | RNG_ENABLED)) == RNG_PRESENT) {
40 rdmsr(MSR_VIA_RNG, lo, hi);
41 lo |= RNG_ENABLE; /* enable RNG unit */
42 wrmsr(MSR_VIA_RNG, low: lo, high: hi);
43 pr_info("CPU: Enabled h/w RNG\n");
44 }
45
46 /* store Centaur Extended Feature Flags as
47 * word 5 of the CPU capability bit array
48 */
49 c->x86_capability[CPUID_C000_0001_EDX] = cpuid_edx(op: 0xC0000001);
50 }
51#ifdef CONFIG_X86_32
52 /* Cyrix III family needs CX8 & PGE explicitly enabled. */
53 if (c->x86_model >= 6 && c->x86_model <= 13) {
54 rdmsr(MSR_VIA_FCR, lo, hi);
55 lo |= (1<<1 | 1<<7);
56 wrmsr(MSR_VIA_FCR, lo, hi);
57 set_cpu_cap(c, X86_FEATURE_CX8);
58 }
59
60 /* Before Nehemiah, the C3's had 3dNOW! */
61 if (c->x86_model >= 6 && c->x86_model < 9)
62 set_cpu_cap(c, X86_FEATURE_3DNOW);
63#endif
64 if (c->x86 == 0x6 && c->x86_model >= 0xf) {
65 c->x86_cache_alignment = c->x86_clflush_size * 2;
66 set_cpu_cap(c, X86_FEATURE_REP_GOOD);
67 }
68
69 if (c->x86 >= 7)
70 set_cpu_cap(c, X86_FEATURE_REP_GOOD);
71}
72
73enum {
74 ECX8 = 1<<1,
75 EIERRINT = 1<<2,
76 DPM = 1<<3,
77 DMCE = 1<<4,
78 DSTPCLK = 1<<5,
79 ELINEAR = 1<<6,
80 DSMC = 1<<7,
81 DTLOCK = 1<<8,
82 EDCTLB = 1<<8,
83 EMMX = 1<<9,
84 DPDC = 1<<11,
85 EBRPRED = 1<<12,
86 DIC = 1<<13,
87 DDC = 1<<14,
88 DNA = 1<<15,
89 ERETSTK = 1<<16,
90 E2MMX = 1<<19,
91 EAMD3D = 1<<20,
92};
93
94static void early_init_centaur(struct cpuinfo_x86 *c)
95{
96#ifdef CONFIG_X86_32
97 /* Emulate MTRRs using Centaur's MCR. */
98 if (c->x86 == 5)
99 set_cpu_cap(c, X86_FEATURE_CENTAUR_MCR);
100#endif
101 if ((c->x86 == 6 && c->x86_model >= 0xf) ||
102 (c->x86 >= 7))
103 set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
104
105#ifdef CONFIG_X86_64
106 set_cpu_cap(c, X86_FEATURE_SYSENTER32);
107#endif
108 if (c->x86_power & (1 << 8)) {
109 set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
110 set_cpu_cap(c, X86_FEATURE_NONSTOP_TSC);
111 }
112}
113
114static void init_centaur(struct cpuinfo_x86 *c)
115{
116#ifdef CONFIG_X86_32
117 char *name;
118 u32 fcr_set = 0;
119 u32 fcr_clr = 0;
120 u32 lo, hi, newlo;
121 u32 aa, bb, cc, dd;
122
123 /*
124 * Bit 31 in normal CPUID used for nonstandard 3DNow ID;
125 * 3DNow is IDd by bit 31 in extended CPUID (1*32+31) anyway
126 */
127 clear_cpu_cap(c, 0*32+31);
128#endif
129 early_init_centaur(c);
130 init_intel_cacheinfo(c);
131
132 if (c->cpuid_level > 9) {
133 unsigned int eax = cpuid_eax(op: 10);
134
135 /*
136 * Check for version and the number of counters
137 * Version(eax[7:0]) can't be 0;
138 * Counters(eax[15:8]) should be greater than 1;
139 */
140 if ((eax & 0xff) && (((eax >> 8) & 0xff) > 1))
141 set_cpu_cap(c, X86_FEATURE_ARCH_PERFMON);
142 }
143
144#ifdef CONFIG_X86_32
145 if (c->x86 == 5) {
146 switch (c->x86_model) {
147 case 4:
148 name = "C6";
149 fcr_set = ECX8|DSMC|EDCTLB|EMMX|ERETSTK;
150 fcr_clr = DPDC;
151 pr_notice("Disabling bugged TSC.\n");
152 clear_cpu_cap(c, X86_FEATURE_TSC);
153 break;
154 case 8:
155 switch (c->x86_stepping) {
156 default:
157 name = "2";
158 break;
159 case 7 ... 9:
160 name = "2A";
161 break;
162 case 10 ... 15:
163 name = "2B";
164 break;
165 }
166 fcr_set = ECX8|DSMC|DTLOCK|EMMX|EBRPRED|ERETSTK|
167 E2MMX|EAMD3D;
168 fcr_clr = DPDC;
169 break;
170 case 9:
171 name = "3";
172 fcr_set = ECX8|DSMC|DTLOCK|EMMX|EBRPRED|ERETSTK|
173 E2MMX|EAMD3D;
174 fcr_clr = DPDC;
175 break;
176 default:
177 name = "??";
178 }
179
180 rdmsr(MSR_IDT_FCR1, lo, hi);
181 newlo = (lo|fcr_set) & (~fcr_clr);
182
183 if (newlo != lo) {
184 pr_info("Centaur FCR was 0x%X now 0x%X\n",
185 lo, newlo);
186 wrmsr(MSR_IDT_FCR1, newlo, hi);
187 } else {
188 pr_info("Centaur FCR is 0x%X\n", lo);
189 }
190 /* Emulate MTRRs using Centaur's MCR. */
191 set_cpu_cap(c, X86_FEATURE_CENTAUR_MCR);
192 /* Report CX8 */
193 set_cpu_cap(c, X86_FEATURE_CX8);
194 /* Set 3DNow! on Winchip 2 and above. */
195 if (c->x86_model >= 8)
196 set_cpu_cap(c, X86_FEATURE_3DNOW);
197 /* See if we can find out some more. */
198 if (cpuid_eax(0x80000000) >= 0x80000005) {
199 /* Yes, we can. */
200 cpuid(0x80000005, &aa, &bb, &cc, &dd);
201 /* Add L1 data and code cache sizes. */
202 c->x86_cache_size = (cc>>24)+(dd>>24);
203 }
204 sprintf(c->x86_model_id, "WinChip %s", name);
205 }
206#endif
207 if (c->x86 == 6 || c->x86 >= 7)
208 init_c3(c);
209#ifdef CONFIG_X86_64
210 set_cpu_cap(c, X86_FEATURE_LFENCE_RDTSC);
211#endif
212
213 init_ia32_feat_ctl(c);
214}
215
216#ifdef CONFIG_X86_32
217static unsigned int
218centaur_size_cache(struct cpuinfo_x86 *c, unsigned int size)
219{
220 /* VIA C3 CPUs (670-68F) need further shifting. */
221 if ((c->x86 == 6) && ((c->x86_model == 7) || (c->x86_model == 8)))
222 size >>= 8;
223
224 /*
225 * There's also an erratum in Nehemiah stepping 1, which
226 * returns '65KB' instead of '64KB'
227 * - Note, it seems this may only be in engineering samples.
228 */
229 if ((c->x86 == 6) && (c->x86_model == 9) &&
230 (c->x86_stepping == 1) && (size == 65))
231 size -= 1;
232 return size;
233}
234#endif
235
236static const struct cpu_dev centaur_cpu_dev = {
237 .c_vendor = "Centaur",
238 .c_ident = { "CentaurHauls" },
239 .c_early_init = early_init_centaur,
240 .c_init = init_centaur,
241#ifdef CONFIG_X86_32
242 .legacy_cache_size = centaur_size_cache,
243#endif
244 .c_x86_vendor = X86_VENDOR_CENTAUR,
245};
246
247cpu_dev_register(centaur_cpu_dev);
248

source code of linux/arch/x86/kernel/cpu/centaur.c