1 /* 2 * Copyright (C) 1994 Linus Torvalds 3 * 4 * Cyrix stuff, June 1998 by: 5 * - Rafael R. Reilova (moved everything from head.S), 6 * <rreilova@ececs.uc.edu> 7 * - Channing Corn (tests & fixes), 8 * - Andrew D. Balsa (code cleanup). 9 */ 10 #include <linux/init.h> 11 #include <linux/utsname.h> 12 #include <asm/bugs.h> 13 #include <asm/processor.h> 14 #include <asm/processor-flags.h> 15 #include <asm/fpu/internal.h> 16 #include <asm/msr.h> 17 #include <asm/paravirt.h> 18 #include <asm/alternative.h> 19 #include <asm/pgtable.h> 20 #include <asm/set_memory.h> 21 22 void __init check_bugs(void) 23 { 24 #ifdef CONFIG_X86_32 25 /* 26 * Regardless of whether PCID is enumerated, the SDM says 27 * that it can't be enabled in 32-bit mode. 28 */ 29 setup_clear_cpu_cap(X86_FEATURE_PCID); 30 #endif 31 32 identify_boot_cpu(); 33 34 if (!IS_ENABLED(CONFIG_SMP)) { 35 pr_info("CPU: "); 36 print_cpu_info(&boot_cpu_data); 37 } 38 39 #ifdef CONFIG_X86_32 40 /* 41 * Check whether we are able to run this kernel safely on SMP. 42 * 43 * - i386 is no longer supported. 44 * - In order to run on anything without a TSC, we need to be 45 * compiled for a i486. 46 */ 47 if (boot_cpu_data.x86 < 4) 48 panic("Kernel requires i486+ for 'invlpg' and other features"); 49 50 init_utsname()->machine[1] = 51 '0' + (boot_cpu_data.x86 > 6 ? 6 : boot_cpu_data.x86); 52 alternative_instructions(); 53 54 fpu__init_check_bugs(); 55 #else /* CONFIG_X86_64 */ 56 alternative_instructions(); 57 58 /* 59 * Make sure the first 2MB area is not mapped by huge pages 60 * There are typically fixed size MTRRs in there and overlapping 61 * MTRRs into large pages causes slow downs. 62 * 63 * Right now we don't do that with gbpages because there seems 64 * very little benefit for that case. 65 */ 66 if (!direct_gbpages) 67 set_memory_4k((unsigned long)__va(0), 1); 68 #endif 69 } 70