2 * (C) Copyright 2008-2011
3 * Graeme Russ, <graeme.russ@gmail.com>
6 * Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
9 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
10 * Marius Groeger <mgroeger@sysgo.de>
13 * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
14 * Alex Zuepke <azu@sysgo.de>
16 * Part of this file is adapted from coreboot
17 * src/arch/x86/lib/cpu.c
19 * SPDX-License-Identifier: GPL-2.0+
26 #include <asm/control_regs.h>
28 #include <asm/processor.h>
29 #include <asm/processor-flags.h>
30 #include <asm/interrupt.h>
31 #include <linux/compiler.h>
33 DECLARE_GLOBAL_DATA_PTR;
36 * Constructor for a conventional segment GDT (or LDT) entry
37 * This is a macro so it can be used in initialisers
39 #define GDT_ENTRY(flags, base, limit) \
40 ((((base) & 0xff000000ULL) << (56-24)) | \
41 (((flags) & 0x0000f0ffULL) << 40) | \
42 (((limit) & 0x000f0000ULL) << (48-16)) | \
43 (((base) & 0x00ffffffULL) << 16) | \
44 (((limit) & 0x0000ffffULL)))
51 struct cpu_device_id {
57 uint8_t x86; /* CPU family */
58 uint8_t x86_vendor; /* CPU vendor */
64 * List of cpu vendor strings along with their normalized
71 { X86_VENDOR_INTEL, "GenuineIntel", },
72 { X86_VENDOR_CYRIX, "CyrixInstead", },
73 { X86_VENDOR_AMD, "AuthenticAMD", },
74 { X86_VENDOR_UMC, "UMC UMC UMC ", },
75 { X86_VENDOR_NEXGEN, "NexGenDriven", },
76 { X86_VENDOR_CENTAUR, "CentaurHauls", },
77 { X86_VENDOR_RISE, "RiseRiseRise", },
78 { X86_VENDOR_TRANSMETA, "GenuineTMx86", },
79 { X86_VENDOR_TRANSMETA, "TransmetaCPU", },
80 { X86_VENDOR_NSC, "Geode by NSC", },
81 { X86_VENDOR_SIS, "SiS SiS SiS ", },
84 static const char *const x86_vendor_name[] = {
85 [X86_VENDOR_INTEL] = "Intel",
86 [X86_VENDOR_CYRIX] = "Cyrix",
87 [X86_VENDOR_AMD] = "AMD",
88 [X86_VENDOR_UMC] = "UMC",
89 [X86_VENDOR_NEXGEN] = "NexGen",
90 [X86_VENDOR_CENTAUR] = "Centaur",
91 [X86_VENDOR_RISE] = "Rise",
92 [X86_VENDOR_TRANSMETA] = "Transmeta",
93 [X86_VENDOR_NSC] = "NSC",
94 [X86_VENDOR_SIS] = "SiS",
97 static void load_ds(u32 segment)
99 asm volatile("movl %0, %%ds" : : "r" (segment * X86_GDT_ENTRY_SIZE));
102 static void load_es(u32 segment)
104 asm volatile("movl %0, %%es" : : "r" (segment * X86_GDT_ENTRY_SIZE));
107 static void load_fs(u32 segment)
109 asm volatile("movl %0, %%fs" : : "r" (segment * X86_GDT_ENTRY_SIZE));
112 static void load_gs(u32 segment)
114 asm volatile("movl %0, %%gs" : : "r" (segment * X86_GDT_ENTRY_SIZE));
117 static void load_ss(u32 segment)
119 asm volatile("movl %0, %%ss" : : "r" (segment * X86_GDT_ENTRY_SIZE));
122 static void load_gdt(const u64 *boot_gdt, u16 num_entries)
126 gdt.len = (num_entries * 8) - 1;
127 gdt.ptr = (u32)boot_gdt;
129 asm volatile("lgdtl %0\n" : : "m" (gdt));
132 void setup_gdt(gd_t *id, u64 *gdt_addr)
134 /* CS: code, read/execute, 4 GB, base 0 */
135 gdt_addr[X86_GDT_ENTRY_32BIT_CS] = GDT_ENTRY(0xc09b, 0, 0xfffff);
137 /* DS: data, read/write, 4 GB, base 0 */
138 gdt_addr[X86_GDT_ENTRY_32BIT_DS] = GDT_ENTRY(0xc093, 0, 0xfffff);
140 /* FS: data, read/write, 4 GB, base (Global Data Pointer) */
141 id->arch.gd_addr = id;
142 gdt_addr[X86_GDT_ENTRY_32BIT_FS] = GDT_ENTRY(0xc093,
143 (ulong)&id->arch.gd_addr, 0xfffff);
145 /* 16-bit CS: code, read/execute, 64 kB, base 0 */
146 gdt_addr[X86_GDT_ENTRY_16BIT_CS] = GDT_ENTRY(0x109b, 0, 0x0ffff);
148 /* 16-bit DS: data, read/write, 64 kB, base 0 */
149 gdt_addr[X86_GDT_ENTRY_16BIT_DS] = GDT_ENTRY(0x1093, 0, 0x0ffff);
151 load_gdt(gdt_addr, X86_GDT_NUM_ENTRIES);
152 load_ds(X86_GDT_ENTRY_32BIT_DS);
153 load_es(X86_GDT_ENTRY_32BIT_DS);
154 load_gs(X86_GDT_ENTRY_32BIT_DS);
155 load_ss(X86_GDT_ENTRY_32BIT_DS);
156 load_fs(X86_GDT_ENTRY_32BIT_FS);
159 int __weak x86_cleanup_before_linux(void)
161 #ifdef CONFIG_BOOTSTAGE_STASH
162 bootstage_stash((void *)CONFIG_BOOTSTAGE_STASH,
163 CONFIG_BOOTSTAGE_STASH_SIZE);
170 * Cyrix CPUs without cpuid or with cpuid not yet enabled can be detected
171 * by the fact that they preserve the flags across the division of 5/2.
172 * PII and PPro exhibit this behavior too, but they have cpuid available.
176 * Perform the Cyrix 5/2 test. A Cyrix won't change
177 * the flags, while other 486 chips will.
179 static inline int test_cyrix_52div(void)
183 __asm__ __volatile__(
184 "sahf\n\t" /* clear flags (%eax = 0x0005) */
185 "div %b2\n\t" /* divide 5 by 2 */
186 "lahf" /* store flags into %ah */
191 /* AH is 0x02 on Cyrix after the divide.. */
192 return (unsigned char) (test >> 8) == 0x02;
196 * Detect a NexGen CPU running without BIOS hypercode new enough
197 * to have CPUID. (Thanks to Herbert Oppmann)
200 static int deep_magic_nexgen_probe(void)
204 __asm__ __volatile__ (
205 " movw $0x5555, %%ax\n"
213 : "=a" (ret) : : "cx", "dx");
217 static bool has_cpuid(void)
219 return flag_is_changeable_p(X86_EFLAGS_ID);
222 static int build_vendor_name(char *vendor_name)
224 struct cpuid_result result;
225 result = cpuid(0x00000000);
226 unsigned int *name_as_ints = (unsigned int *)vendor_name;
228 name_as_ints[0] = result.ebx;
229 name_as_ints[1] = result.edx;
230 name_as_ints[2] = result.ecx;
235 static void identify_cpu(struct cpu_device_id *cpu)
237 char vendor_name[16];
240 vendor_name[0] = '\0'; /* Unset */
242 /* Find the id and vendor_name */
244 /* Its a 486 if we can modify the AC flag */
245 if (flag_is_changeable_p(X86_EFLAGS_AC))
246 cpu->device = 0x00000400; /* 486 */
248 cpu->device = 0x00000300; /* 386 */
249 if ((cpu->device == 0x00000400) && test_cyrix_52div()) {
250 memcpy(vendor_name, "CyrixInstead", 13);
251 /* If we ever care we can enable cpuid here */
253 /* Detect NexGen with old hypercode */
254 else if (deep_magic_nexgen_probe())
255 memcpy(vendor_name, "NexGenDriven", 13);
260 cpuid_level = build_vendor_name(vendor_name);
261 vendor_name[12] = '\0';
263 /* Intel-defined flags: level 0x00000001 */
264 if (cpuid_level >= 0x00000001) {
265 cpu->device = cpuid_eax(0x00000001);
267 /* Have CPUID level 0 only unheard of */
268 cpu->device = 0x00000400;
271 cpu->vendor = X86_VENDOR_UNKNOWN;
272 for (i = 0; i < ARRAY_SIZE(x86_vendors); i++) {
273 if (memcmp(vendor_name, x86_vendors[i].name, 12) == 0) {
274 cpu->vendor = x86_vendors[i].vendor;
280 static inline void get_fms(struct cpuinfo_x86 *c, uint32_t tfms)
282 c->x86 = (tfms >> 8) & 0xf;
283 c->x86_model = (tfms >> 4) & 0xf;
284 c->x86_mask = tfms & 0xf;
286 c->x86 += (tfms >> 20) & 0xff;
288 c->x86_model += ((tfms >> 16) & 0xF) << 4;
291 int x86_cpu_init_f(void)
293 const u32 em_rst = ~X86_CR0_EM;
294 const u32 mp_ne_set = X86_CR0_MP | X86_CR0_NE;
296 /* initialize FPU, reset EM, set MP and NE */
298 "movl %%cr0, %%eax\n" \
301 "movl %%eax, %%cr0\n" \
302 : : "i" (em_rst), "i" (mp_ne_set) : "eax");
304 /* identify CPU via cpuid and store the decoded info into gd->arch */
306 struct cpu_device_id cpu;
307 struct cpuinfo_x86 c;
310 get_fms(&c, cpu.device);
311 gd->arch.x86 = c.x86;
312 gd->arch.x86_vendor = cpu.vendor;
313 gd->arch.x86_model = c.x86_model;
314 gd->arch.x86_mask = c.x86_mask;
315 gd->arch.x86_device = cpu.device;
321 int x86_cpu_init_r(void)
323 /* Initialize core interrupt and exception functionality of CPU */
324 cpu_init_interrupts();
327 int cpu_init_r(void) __attribute__((weak, alias("x86_cpu_init_r")));
329 void x86_enable_caches(void)
334 cr0 &= ~(X86_CR0_NW | X86_CR0_CD);
338 void enable_caches(void) __attribute__((weak, alias("x86_enable_caches")));
340 void x86_disable_caches(void)
345 cr0 |= X86_CR0_NW | X86_CR0_CD;
350 void disable_caches(void) __attribute__((weak, alias("x86_disable_caches")));
352 int x86_init_cache(void)
358 int init_cache(void) __attribute__((weak, alias("x86_init_cache")));
360 int do_reset(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
362 printf("resetting ...\n");
366 disable_interrupts();
373 void flush_cache(unsigned long dummy1, unsigned long dummy2)
378 void __attribute__ ((regparm(0))) generate_gpf(void);
380 /* segment 0x70 is an arbitrary segment which does not exist */
381 asm(".globl generate_gpf\n"
382 ".hidden generate_gpf\n"
383 ".type generate_gpf, @function\n"
385 "ljmp $0x70, $0x47114711\n");
387 __weak void reset_cpu(ulong addr)
389 printf("Resetting using x86 Triple Fault\n");
390 set_vector(13, generate_gpf); /* general protection fault handler */
391 set_vector(8, generate_gpf); /* double fault handler */
392 generate_gpf(); /* start the show */
395 int dcache_status(void)
397 return !(read_cr0() & 0x40000000);
400 /* Define these functions to allow ehch-hcd to function */
401 void flush_dcache_range(unsigned long start, unsigned long stop)
405 void invalidate_dcache_range(unsigned long start, unsigned long stop)
409 void dcache_enable(void)
414 void dcache_disable(void)
419 void icache_enable(void)
423 void icache_disable(void)
427 int icache_status(void)
432 void cpu_enable_paging_pae(ulong cr3)
434 __asm__ __volatile__(
435 /* Load the page table address */
438 "movl %%cr4, %%eax\n"
439 "orl $0x00000020, %%eax\n"
440 "movl %%eax, %%cr4\n"
442 "movl %%cr0, %%eax\n"
443 "orl $0x80000000, %%eax\n"
444 "movl %%eax, %%cr0\n"
450 void cpu_disable_paging_pae(void)
452 /* Turn off paging */
453 __asm__ __volatile__ (
455 "movl %%cr0, %%eax\n"
456 "andl $0x7fffffff, %%eax\n"
457 "movl %%eax, %%cr0\n"
459 "movl %%cr4, %%eax\n"
460 "andl $0xffffffdf, %%eax\n"
461 "movl %%eax, %%cr4\n"
467 static bool can_detect_long_mode(void)
469 return cpuid_eax(0x80000000) > 0x80000000UL;
472 static bool has_long_mode(void)
474 return cpuid_edx(0x80000001) & (1 << 29) ? true : false;
477 int cpu_has_64bit(void)
479 return has_cpuid() && can_detect_long_mode() &&
483 const char *cpu_vendor_name(int vendor)
486 name = "<invalid cpu vendor>";
487 if ((vendor < (ARRAY_SIZE(x86_vendor_name))) &&
488 (x86_vendor_name[vendor] != 0))
489 name = x86_vendor_name[vendor];
494 void fill_processor_name(char *processor_name)
496 struct cpuid_result regs;
497 char temp_processor_name[49];
498 char *processor_name_start;
499 unsigned int *name_as_ints = (unsigned int *)temp_processor_name;
502 for (i = 0; i < 3; i++) {
503 regs = cpuid(0x80000002 + i);
504 name_as_ints[i * 4 + 0] = regs.eax;
505 name_as_ints[i * 4 + 1] = regs.ebx;
506 name_as_ints[i * 4 + 2] = regs.ecx;
507 name_as_ints[i * 4 + 3] = regs.edx;
510 temp_processor_name[48] = 0;
512 /* Skip leading spaces. */
513 processor_name_start = temp_processor_name;
514 while (*processor_name_start == ' ')
515 processor_name_start++;
517 memset(processor_name, 0, 49);
518 strcpy(processor_name, processor_name_start);
521 int print_cpuinfo(void)
523 printf("CPU: %s, vendor %s, device %xh\n",
524 cpu_has_64bit() ? "x86_64" : "x86",
525 cpu_vendor_name(gd->arch.x86_vendor), gd->arch.x86_device);
530 #define PAGETABLE_SIZE (6 * 4096)
533 * build_pagetable() - build a flat 4GiB page table structure for 64-bti mode
535 * @pgtable: Pointer to a 24iKB block of memory
537 static void build_pagetable(uint32_t *pgtable)
541 memset(pgtable, '\0', PAGETABLE_SIZE);
543 /* Level 4 needs a single entry */
544 pgtable[0] = (uint32_t)&pgtable[1024] + 7;
546 /* Level 3 has one 64-bit entry for each GiB of memory */
547 for (i = 0; i < 4; i++) {
548 pgtable[1024 + i * 2] = (uint32_t)&pgtable[2048] +
552 /* Level 2 has 2048 64-bit entries, each repesenting 2MiB */
553 for (i = 0; i < 2048; i++)
554 pgtable[2048 + i * 2] = 0x183 + (i << 21UL);
557 int cpu_jump_to_64bit(ulong setup_base, ulong target)
561 pgtable = memalign(4096, PAGETABLE_SIZE);
565 build_pagetable(pgtable);
566 cpu_call64((ulong)pgtable, setup_base, target);