x86: protect against sigaltstack wraparound
[linux-2.6] / arch / x86 / kernel / cpu / amd.c
1 #include <linux/init.h>
2 #include <linux/bitops.h>
3 #include <linux/mm.h>
4 #include <asm/io.h>
5 #include <asm/processor.h>
6 #include <asm/apic.h>
7 #include <asm/mach_apic.h>
8
9 #include "cpu.h"
10
11 /*
12  *      B step AMD K6 before B 9730xxxx have hardware bugs that can cause
13  *      misexecution of code under Linux. Owners of such processors should
14  *      contact AMD for precise details and a CPU swap.
15  *
16  *      See     http://www.multimania.com/poulot/k6bug.html
17  *              http://www.amd.com/K6/k6docs/revgd.html
18  *
19  *      The following test is erm.. interesting. AMD neglected to up
20  *      the chip setting when fixing the bug but they also tweaked some
21  *      performance at the same time..
22  */
23  
24 extern void vide(void);
25 __asm__(".align 4\nvide: ret");
26
27 #ifdef CONFIG_X86_LOCAL_APIC
28 #define ENABLE_C1E_MASK         0x18000000
29 #define CPUID_PROCESSOR_SIGNATURE       1
30 #define CPUID_XFAM              0x0ff00000
31 #define CPUID_XFAM_K8           0x00000000
32 #define CPUID_XFAM_10H          0x00100000
33 #define CPUID_XFAM_11H          0x00200000
34 #define CPUID_XMOD              0x000f0000
35 #define CPUID_XMOD_REV_F        0x00040000
36
37 /* AMD systems with C1E don't have a working lAPIC timer. Check for that. */
38 static __cpuinit int amd_apic_timer_broken(void)
39 {
40         u32 lo, hi;
41         u32 eax = cpuid_eax(CPUID_PROCESSOR_SIGNATURE);
42         switch (eax & CPUID_XFAM) {
43         case CPUID_XFAM_K8:
44                 if ((eax & CPUID_XMOD) < CPUID_XMOD_REV_F)
45                         break;
46         case CPUID_XFAM_10H:
47         case CPUID_XFAM_11H:
48                 rdmsr(MSR_K8_ENABLE_C1E, lo, hi);
49                 if (lo & ENABLE_C1E_MASK) {
50                         if (smp_processor_id() != boot_cpu_physical_apicid)
51                                 printk(KERN_INFO "AMD C1E detected late. "
52                                        "        Force timer broadcast.\n");
53                         return 1;
54                 }
55                 break;
56         default:
57                 /* err on the side of caution */
58                 return 1;
59         }
60         return 0;
61 }
62 #endif
63
64 int force_mwait __cpuinitdata;
65
66 static void __cpuinit init_amd(struct cpuinfo_x86 *c)
67 {
68         u32 l, h;
69         int mbytes = num_physpages >> (20-PAGE_SHIFT);
70         int r;
71
72 #ifdef CONFIG_SMP
73         unsigned long long value;
74
75         /* Disable TLB flush filter by setting HWCR.FFDIS on K8
76          * bit 6 of msr C001_0015
77          *
78          * Errata 63 for SH-B3 steppings
79          * Errata 122 for all steppings (F+ have it disabled by default)
80          */
81         if (c->x86 == 15) {
82                 rdmsrl(MSR_K7_HWCR, value);
83                 value |= 1 << 6;
84                 wrmsrl(MSR_K7_HWCR, value);
85         }
86 #endif
87
88         /*
89          *      FIXME: We should handle the K5 here. Set up the write
90          *      range and also turn on MSR 83 bits 4 and 31 (write alloc,
91          *      no bus pipeline)
92          */
93
94         /* Bit 31 in normal CPUID used for nonstandard 3DNow ID;
95            3DNow is IDd by bit 31 in extended CPUID (1*32+31) anyway */
96         clear_bit(0*32+31, c->x86_capability);
97         
98         r = get_model_name(c);
99
100         switch(c->x86)
101         {
102                 case 4:
103                 /*
104                  * General Systems BIOSen alias the cpu frequency registers
105                  * of the Elan at 0x000df000. Unfortuantly, one of the Linux
106                  * drivers subsequently pokes it, and changes the CPU speed.
107                  * Workaround : Remove the unneeded alias.
108                  */
109 #define CBAR            (0xfffc) /* Configuration Base Address  (32-bit) */
110 #define CBAR_ENB        (0x80000000)
111 #define CBAR_KEY        (0X000000CB)
112                         if (c->x86_model==9 || c->x86_model == 10) {
113                                 if (inl (CBAR) & CBAR_ENB)
114                                         outl (0 | CBAR_KEY, CBAR);
115                         }
116                         break;
117                 case 5:
118                         if( c->x86_model < 6 )
119                         {
120                                 /* Based on AMD doc 20734R - June 2000 */
121                                 if ( c->x86_model == 0 ) {
122                                         clear_bit(X86_FEATURE_APIC, c->x86_capability);
123                                         set_bit(X86_FEATURE_PGE, c->x86_capability);
124                                 }
125                                 break;
126                         }
127                         
128                         if ( c->x86_model == 6 && c->x86_mask == 1 ) {
129                                 const int K6_BUG_LOOP = 1000000;
130                                 int n;
131                                 void (*f_vide)(void);
132                                 unsigned long d, d2;
133                                 
134                                 printk(KERN_INFO "AMD K6 stepping B detected - ");
135                                 
136                                 /*
137                                  * It looks like AMD fixed the 2.6.2 bug and improved indirect 
138                                  * calls at the same time.
139                                  */
140
141                                 n = K6_BUG_LOOP;
142                                 f_vide = vide;
143                                 rdtscl(d);
144                                 while (n--) 
145                                         f_vide();
146                                 rdtscl(d2);
147                                 d = d2-d;
148
149                                 if (d > 20*K6_BUG_LOOP) 
150                                         printk("system stability may be impaired when more than 32 MB are used.\n");
151                                 else 
152                                         printk("probably OK (after B9730xxxx).\n");
153                                 printk(KERN_INFO "Please see http://membres.lycos.fr/poulot/k6bug.html\n");
154                         }
155
156                         /* K6 with old style WHCR */
157                         if (c->x86_model < 8 ||
158                            (c->x86_model== 8 && c->x86_mask < 8)) {
159                                 /* We can only write allocate on the low 508Mb */
160                                 if(mbytes>508)
161                                         mbytes=508;
162
163                                 rdmsr(MSR_K6_WHCR, l, h);
164                                 if ((l&0x0000FFFF)==0) {
165                                         unsigned long flags;
166                                         l=(1<<0)|((mbytes/4)<<1);
167                                         local_irq_save(flags);
168                                         wbinvd();
169                                         wrmsr(MSR_K6_WHCR, l, h);
170                                         local_irq_restore(flags);
171                                         printk(KERN_INFO "Enabling old style K6 write allocation for %d Mb\n",
172                                                 mbytes);
173                                 }
174                                 break;
175                         }
176
177                         if ((c->x86_model == 8 && c->x86_mask >7) ||
178                              c->x86_model == 9 || c->x86_model == 13) {
179                                 /* The more serious chips .. */
180
181                                 if(mbytes>4092)
182                                         mbytes=4092;
183
184                                 rdmsr(MSR_K6_WHCR, l, h);
185                                 if ((l&0xFFFF0000)==0) {
186                                         unsigned long flags;
187                                         l=((mbytes>>2)<<22)|(1<<16);
188                                         local_irq_save(flags);
189                                         wbinvd();
190                                         wrmsr(MSR_K6_WHCR, l, h);
191                                         local_irq_restore(flags);
192                                         printk(KERN_INFO "Enabling new style K6 write allocation for %d Mb\n",
193                                                 mbytes);
194                                 }
195
196                                 /*  Set MTRR capability flag if appropriate */
197                                 if (c->x86_model == 13 || c->x86_model == 9 ||
198                                    (c->x86_model == 8 && c->x86_mask >= 8))
199                                         set_bit(X86_FEATURE_K6_MTRR, c->x86_capability);
200                                 break;
201                         }
202
203                         if (c->x86_model == 10) {
204                                 /* AMD Geode LX is model 10 */
205                                 /* placeholder for any needed mods */
206                                 break;
207                         }
208                         break;
209                 case 6: /* An Athlon/Duron */
210  
211                         /* Bit 15 of Athlon specific MSR 15, needs to be 0
212                          * to enable SSE on Palomino/Morgan/Barton CPU's.
213                          * If the BIOS didn't enable it already, enable it here.
214                          */
215                         if (c->x86_model >= 6 && c->x86_model <= 10) {
216                                 if (!cpu_has(c, X86_FEATURE_XMM)) {
217                                         printk(KERN_INFO "Enabling disabled K7/SSE Support.\n");
218                                         rdmsr(MSR_K7_HWCR, l, h);
219                                         l &= ~0x00008000;
220                                         wrmsr(MSR_K7_HWCR, l, h);
221                                         set_bit(X86_FEATURE_XMM, c->x86_capability);
222                                 }
223                         }
224
225                         /* It's been determined by AMD that Athlons since model 8 stepping 1
226                          * are more robust with CLK_CTL set to 200xxxxx instead of 600xxxxx
227                          * As per AMD technical note 27212 0.2
228                          */
229                         if ((c->x86_model == 8 && c->x86_mask>=1) || (c->x86_model > 8)) {
230                                 rdmsr(MSR_K7_CLK_CTL, l, h);
231                                 if ((l & 0xfff00000) != 0x20000000) {
232                                         printk ("CPU: CLK_CTL MSR was %x. Reprogramming to %x\n", l,
233                                                 ((l & 0x000fffff)|0x20000000));
234                                         wrmsr(MSR_K7_CLK_CTL, (l & 0x000fffff)|0x20000000, h);
235                                 }
236                         }
237                         break;
238         }
239
240         switch (c->x86) {
241         case 15:
242         /* Use K8 tuning for Fam10h and Fam11h */
243         case 0x10:
244         case 0x11:
245                 set_bit(X86_FEATURE_K8, c->x86_capability);
246                 break;
247         case 6:
248                 set_bit(X86_FEATURE_K7, c->x86_capability); 
249                 break;
250         }
251         if (c->x86 >= 6)
252                 set_bit(X86_FEATURE_FXSAVE_LEAK, c->x86_capability);
253
254         display_cacheinfo(c);
255
256         if (cpuid_eax(0x80000000) >= 0x80000008) {
257                 c->x86_max_cores = (cpuid_ecx(0x80000008) & 0xff) + 1;
258         }
259
260         if (cpuid_eax(0x80000000) >= 0x80000007) {
261                 c->x86_power = cpuid_edx(0x80000007);
262                 if (c->x86_power & (1<<8))
263                         set_bit(X86_FEATURE_CONSTANT_TSC, c->x86_capability);
264         }
265
266 #ifdef CONFIG_X86_HT
267         /*
268          * On a AMD multi core setup the lower bits of the APIC id
269          * distinguish the cores.
270          */
271         if (c->x86_max_cores > 1) {
272                 int cpu = smp_processor_id();
273                 unsigned bits = (cpuid_ecx(0x80000008) >> 12) & 0xf;
274
275                 if (bits == 0) {
276                         while ((1 << bits) < c->x86_max_cores)
277                                 bits++;
278                 }
279                 c->cpu_core_id = c->phys_proc_id & ((1<<bits)-1);
280                 c->phys_proc_id >>= bits;
281                 printk(KERN_INFO "CPU %d(%d) -> Core %d\n",
282                        cpu, c->x86_max_cores, c->cpu_core_id);
283         }
284 #endif
285
286         if (cpuid_eax(0x80000000) >= 0x80000006) {
287                 if ((c->x86 == 0x10) && (cpuid_edx(0x80000006) & 0xf000))
288                         num_cache_leaves = 4;
289                 else
290                         num_cache_leaves = 3;
291         }
292
293 #ifdef CONFIG_X86_LOCAL_APIC
294         if (amd_apic_timer_broken())
295                 local_apic_timer_disabled = 1;
296 #endif
297
298         if (c->x86 == 0x10 && !force_mwait)
299                 clear_bit(X86_FEATURE_MWAIT, c->x86_capability);
300
301         /* K6s reports MCEs but don't actually have all the MSRs */
302         if (c->x86 < 6)
303                 clear_bit(X86_FEATURE_MCE, c->x86_capability);
304 }
305
306 static unsigned int __cpuinit amd_size_cache(struct cpuinfo_x86 * c, unsigned int size)
307 {
308         /* AMD errata T13 (order #21922) */
309         if ((c->x86 == 6)) {
310                 if (c->x86_model == 3 && c->x86_mask == 0)      /* Duron Rev A0 */
311                         size = 64;
312                 if (c->x86_model == 4 &&
313                     (c->x86_mask==0 || c->x86_mask==1)) /* Tbird rev A1/A2 */
314                         size = 256;
315         }
316         return size;
317 }
318
319 static struct cpu_dev amd_cpu_dev __cpuinitdata = {
320         .c_vendor       = "AMD",
321         .c_ident        = { "AuthenticAMD" },
322         .c_models = {
323                 { .vendor = X86_VENDOR_AMD, .family = 4, .model_names =
324                   {
325                           [3] = "486 DX/2",
326                           [7] = "486 DX/2-WB",
327                           [8] = "486 DX/4", 
328                           [9] = "486 DX/4-WB", 
329                           [14] = "Am5x86-WT",
330                           [15] = "Am5x86-WB" 
331                   }
332                 },
333         },
334         .c_init         = init_amd,
335         .c_size_cache   = amd_size_cache,
336 };
337
338 int __init amd_init_cpu(void)
339 {
340         cpu_devs[X86_VENDOR_AMD] = &amd_cpu_dev;
341         return 0;
342 }