1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Copyright (C) 1994 Linus Torvalds 4 * 5 * Cyrix stuff, June 1998 by: 6 * - Rafael R. Reilova (moved everything from head.S), 7 * <rreilova@ececs.uc.edu> 8 * - Channing Corn (tests & fixes), 9 * - Andrew D. Balsa (code cleanup). 10 */ 11 #include <linux/init.h> 12 #include <linux/utsname.h> 13 #include <asm/bugs.h> 14 #include <asm/processor.h> 15 #include <asm/processor-flags.h> 16 #include <asm/fpu/internal.h> 17 #include <asm/msr.h> 18 #include <asm/paravirt.h> 19 #include <asm/alternative.h> 20 #include <asm/pgtable.h> 21 #include <asm/set_memory.h> 22 23 void __init check_bugs(void) 24 { 25 identify_boot_cpu(); 26 27 if (!IS_ENABLED(CONFIG_SMP)) { 28 pr_info("CPU: "); 29 print_cpu_info(&boot_cpu_data); 30 } 31 32 #ifdef CONFIG_X86_32 33 /* 34 * Check whether we are able to run this kernel safely on SMP. 35 * 36 * - i386 is no longer supported. 37 * - In order to run on anything without a TSC, we need to be 38 * compiled for a i486. 39 */ 40 if (boot_cpu_data.x86 < 4) 41 panic("Kernel requires i486+ for 'invlpg' and other features"); 42 43 init_utsname()->machine[1] = 44 '0' + (boot_cpu_data.x86 > 6 ? 6 : boot_cpu_data.x86); 45 alternative_instructions(); 46 47 fpu__init_check_bugs(); 48 #else /* CONFIG_X86_64 */ 49 alternative_instructions(); 50 51 /* 52 * Make sure the first 2MB area is not mapped by huge pages 53 * There are typically fixed size MTRRs in there and overlapping 54 * MTRRs into large pages causes slow downs. 55 * 56 * Right now we don't do that with gbpages because there seems 57 * very little benefit for that case. 58 */ 59 if (!direct_gbpages) 60 set_memory_4k((unsigned long)__va(0), 1); 61 #endif 62 } 63