[linuxkernelnewbies] L1/2/3 cache information - how to derive it?

[Peter Teoh]

http://www.cs.fsu.edu/~baker/devices/lxr/http/source/linux/arch/x86/kernel/cpu/common.c 122 123 void __cpuinit display_cacheinfo(struct cpuinfo_x86 *c) 124 { 125 unsigned int n, dummy, ecx, edx, l2size; 126 127 n = cpuid_eax(0x80000000); 128 129 if (n >= 0x80000005) { 130 cpuid(0x80000005, &dummy, &dummy, &ecx, &edx); 131 printk(KERN_INFO "CPU: L1 I Cache: %dK (%d bytes/line), D cache %dK (%d bytes/line)\n", 132 edx>>24, edx&0xFF, ecx>>24, ecx&0xFF); 133 c->x86_cache_size=(ecx>>24)+(edx>>24); 134 } 135 136 if (n < 0x80000006) /* Some chips just has a large L1. */ 137 return; 138 139 ecx = cpuid_ecx(0x80000006); 140 l2size = ecx >> 16; 141 142 /* do processor-specific cache resizing */ 143 if (this_cpu->c_size_cache) 144 l2size = this_cpu->c_size_cache(c,l2size); 145 146 /* Allow user to override all this if necessary. */ 147 if (cachesize_override != -1) 148 l2size = cachesize_override; 149 150 if ( l2size == 0 ) 151 return; /* Again, no L2 cache is possible */ 152 153 c->x86_cache_size = l2size; 154 155 printk(KERN_INFO "CPU: L2 Cache: %dK (%d bytes/line)\n", 156 l2size, ecx & 0xFF); 157 } 158 159 /* Naming convention should be: <Name> [(<Codename>)] */ 160 /* This table only is used unless init_<vendor>() below doesn't set it; */ 161 /* in particular, if CPUID levels 0x80000002..4 are supported, this isn't used */ 162 163 /* Look up CPU names by table lookup. */ 164 static char __cpuinit *table_lookup_model(struct cpuinfo_x86 *c) 165 { 166 struct cpu_model_info *info; 167 168 if ( c->x86_model >= 16 ) 169 return NULL; /* Range check */ 170 171 if (!this_cpu) 172 return NULL; 173 174 info = this_cpu->c_models; 175 176 while (info && info->family) { 177 if (info->family == c->x86) 178 return info->model_names[c->x86_model]; 179 info++; 180 } 181 return NULL; /* Not found */ 182 } 183 184 185 static void __cpuinit get_cpu_vendor(struct cpuinfo_x86 *c, int early) 186 { 187 char *v = c->x86_vendor_id; 188 int i; 189 static int printed; 190 191 for (i = 0; i < X86_VENDOR_NUM; i++) { 192 if (cpu_devs[i]) { 193 if (!strcmp(v,cpu_devs[i]->c_ident[0]) || 194 (cpu_devs[i]->c_ident[1] && 195 !strcmp(v,cpu_devs[i]->c_ident[1]))) { 196 c->x86_vendor = i; 197 if (!early) 198 this_cpu = cpu_devs[i]; 199 return; 200 } 201 } 202 } 203 if (!printed) { 204 printed++; 205 printk(KERN_ERR "CPU: Vendor unknown, using generic init.\n"); 206 printk(KERN_ERR "CPU: Your system may be unstable.\n"); 207 } 208 c->x86_vendor = X86_VENDOR_UNKNOWN; 209 this_cpu = &default_cpu; 210 } 211 212 213 static int __init x86_fxsr_setup(char * s) 214 { 215 setup_clear_cpu_cap(X86_FEATURE_FXSR); 216 setup_clear_cpu_cap(X86_FEATURE_XMM); 217 return 1; 218 } 219 __setup("nofxsr", x86_fxsr_setup); 220 221 222 static int __init x86_sep_setup(char * s) 223 { 224 setup_clear_cpu_cap(X86_FEATURE_SEP); 225 return 1; 226 } 227 __setup("nosep", x86_sep_setup); 228 /* Do minimum CPU detection early. Fields really needed: vendor, cpuid_level, family, model, mask, cache alignment. The others are not touched to avoid unwanted side effects. WARNING: this function is only called on the BP. Don't add code here that is supposed to run on all CPUs. */ static void __init early_cpu_detect(void) { struct cpuinfo_x86 *c = &boot_cpu_data; c->x86_cache_alignment = 32; c->x86_clflush_size = 32; if (!have_cpuid_p()) return; cpu_detect(c); get_cpu_vendor(c, 1); switch (c->x86_vendor) { case X86_VENDOR_AMD: early_init_amd(c); break; case X86_VENDOR_INTEL: early_init_intel(c); break; } early_get_cap(c); } Notice how the above function have evolved to the following (2.6.31-rc9): 514 void __cpuinit cpu_detect(struct cpuinfo_x86 *c) 515 { 516 /* Get vendor name */ 517 cpuid(0x00000000, (unsigned int *)&c->cpuid_level, 518 (unsigned int *)&c->x86_vendor_id[0], 519 (unsigned int *)&c->x86_vendor_id[8], 520 (unsigned int *)&c->x86_vendor_id[4]); 521 522 c->x86 = 4; 523 /* Intel-defined flags: level 0x00000001 */ 524 if (c->cpuid_level >= 0x00000001) { 525 u32 junk, tfms, cap0, misc; 526 527 cpuid(0x00000001, &tfms, &misc, &junk, &cap0); 528 c->x86 = (tfms >> 8) & 0xf; 529 c->x86_model = (tfms >> 4) & 0xf; 530 c->x86_mask = tfms & 0xf; 531 532 if (c->x86 == 0xf) 533 c->x86 += (tfms >> 20) & 0xff; 534 if (c->x86 >= 0x6) 535 c->x86_model += ((tfms >> 16) & 0xf) << 4; 536 537 if (cap0 & (1<<19)) { 538 c->x86_clflush_size = ((misc >> 8) & 0xff) * 8; 539 c->x86_cache_alignment = c->x86_clflush_size; 540 } 541 } 542 } 611 /* 612 * Do minimum CPU detection early. 613 * Fields really needed: vendor, cpuid_level, family, model, mask, 614 * cache alignment. 615 * The others are not touched to avoid unwanted side effects. 616 * 617 * WARNING: this function is only called on the BP. Don't add code here 618 * that is supposed to run on all CPUs. 619 */ 620 static void __init early_identify_cpu(struct cpuinfo_x86 *c) 621 { 622 #ifdef CONFIG_X86_64 623 c->x86_clflush_size = 64; 624 c->x86_phys_bits = 36; 625 c->x86_virt_bits = 48; 626 #else 627 c->x86_clflush_size = 32; 628 c->x86_phys_bits = 32; 629 c->x86_virt_bits = 32; 630 #endif 631 c->x86_cache_alignment = c->x86_clflush_size; 632 633 memset(&c->x86_capability, 0, sizeof c->x86_capability); 634 c->extended_cpuid_level = 0; 635 636 if (!have_cpuid_p()) 637 identify_cpu_without_cpuid(c); 638 639 /* cyrix could have cpuid enabled via c_identify()*/ 640 if (!have_cpuid_p()) 641 return; 642 643 cpu_detect(c); 644 645 get_cpu_vendor(c); 646 647 get_cpu_cap(c); 648 649 if (this_cpu->c_early_init) 650 this_cpu->c_early_init(c); 651 652 #ifdef CONFIG_SMP 653 c->cpu_index = boot_cpu_id; 654 #endif 655 filter_cpuid_features(c, false); 656 } 657