1 /*- 2 * Copyright (c) 1998 Michael Smith <msmith@freebsd.org> 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 */ 26 27 #include <sys/cdefs.h> 28 #define __ELF_WORD_SIZE 64 29 #include <sys/param.h> 30 #include <sys/exec.h> 31 #include <sys/linker.h> 32 #ifdef DEBUG 33 #include <machine/_inttypes.h> 34 #endif 35 #include <string.h> 36 #include <i386/include/bootinfo.h> 37 #include <machine/elf.h> 38 #include <stand.h> 39 40 #include "bootstrap.h" 41 #include "libuserboot.h" 42 43 static int elf64_exec(struct preloaded_file *amp); 44 static int elf64_obj_exec(struct preloaded_file *amp); 45 46 struct file_format amd64_elf = { elf64_loadfile, elf64_exec }; 47 struct file_format amd64_elf_obj = { elf64_obj_loadfile, elf64_obj_exec }; 48 49 #define MSR_EFER 0xc0000080 50 #define EFER_LME 0x00000100 51 #define EFER_LMA 0x00000400 /* Long mode active (R) */ 52 #define CR4_PAE 0x00000020 53 #define CR4_VMXE (1UL << 13) 54 #define CR4_PSE 0x00000010 55 #define CR0_PG 0x80000000 56 #define CR0_PE 0x00000001 /* Protected mode Enable */ 57 #define CR0_NE 0x00000020 /* Numeric Error enable (EX16 vs IRQ13) */ 58 59 #define PG_V 0x001 60 #define PG_RW 0x002 61 #define PG_PS 0x080 62 63 typedef uint64_t p4_entry_t; 64 typedef uint64_t p3_entry_t; 65 typedef uint64_t p2_entry_t; 66 67 #define GUEST_NULL_SEL 0 68 #define GUEST_CODE_SEL 1 69 #define GUEST_DATA_SEL 2 70 #define GUEST_GDTR_LIMIT (3 * 8 - 1) 71 72 static void 73 setup_freebsd_gdt(uint64_t *gdtr) 74 { 75 gdtr[GUEST_NULL_SEL] = 0; 76 gdtr[GUEST_CODE_SEL] = 0x0020980000000000; 77 gdtr[GUEST_DATA_SEL] = 0x0000900000000000; 78 } 79 80 /* 81 * There is an ELF kernel and one or more ELF modules loaded. 82 * We wish to start executing the kernel image, so make such 83 * preparations as are required, and do so. 84 */ 85 static int 86 elf64_exec(struct preloaded_file *fp) 87 { 88 struct file_metadata *md; 89 Elf_Ehdr *ehdr; 90 vm_offset_t modulep, kernend; 91 int err; 92 int i; 93 uint32_t stack[1024]; 94 p4_entry_t PT4[512]; 95 p3_entry_t PT3[512]; 96 p2_entry_t PT2[512]; 97 uint64_t gdtr[3]; 98 99 if ((md = file_findmetadata(fp, MODINFOMD_ELFHDR)) == NULL) 100 return(EFTYPE); 101 ehdr = (Elf_Ehdr *)&(md->md_data); 102 103 err = bi_load64(fp->f_args, &modulep, &kernend); 104 if (err != 0) 105 return(err); 106 107 bzero(PT4, PAGE_SIZE); 108 bzero(PT3, PAGE_SIZE); 109 bzero(PT2, PAGE_SIZE); 110 111 /* 112 * Build a scratch stack at physical 0x1000, page tables: 113 * PT4 at 0x2000, 114 * PT3 at 0x3000, 115 * PT2 at 0x4000, 116 * gdtr at 0x5000, 117 */ 118 119 /* 120 * This is kinda brutal, but every single 1GB VM memory segment 121 * points to the same first 1GB of physical memory. But it is 122 * more than adequate. 123 */ 124 for (i = 0; i < 512; i++) { 125 /* Each slot of the level 4 pages points to the same level 3 page */ 126 PT4[i] = (p4_entry_t) 0x3000; 127 PT4[i] |= PG_V | PG_RW; 128 129 /* Each slot of the level 3 pages points to the same level 2 page */ 130 PT3[i] = (p3_entry_t) 0x4000; 131 PT3[i] |= PG_V | PG_RW; 132 133 /* The level 2 page slots are mapped with 2MB pages for 1GB. */ 134 PT2[i] = i * (2 * 1024 * 1024); 135 PT2[i] |= PG_V | PG_RW | PG_PS; 136 } 137 138 #ifdef DEBUG 139 printf("Start @ %#"PRIx64" ...\n", ehdr->e_entry); 140 #endif 141 142 dev_cleanup(); 143 144 stack[0] = 0; /* return address */ 145 stack[1] = modulep; 146 stack[2] = kernend; 147 CALLBACK(copyin, stack, 0x1000, sizeof(stack)); 148 CALLBACK(copyin, PT4, 0x2000, sizeof(PT4)); 149 CALLBACK(copyin, PT3, 0x3000, sizeof(PT3)); 150 CALLBACK(copyin, PT2, 0x4000, sizeof(PT2)); 151 CALLBACK(setreg, 4, 0x1000); 152 153 CALLBACK(setmsr, MSR_EFER, EFER_LMA | EFER_LME); 154 CALLBACK(setcr, 4, CR4_PAE | CR4_VMXE); 155 CALLBACK(setcr, 3, 0x2000); 156 CALLBACK(setcr, 0, CR0_PG | CR0_PE | CR0_NE); 157 158 setup_freebsd_gdt(gdtr); 159 CALLBACK(copyin, gdtr, 0x5000, sizeof(gdtr)); 160 CALLBACK(setgdt, 0x5000, sizeof(gdtr)); 161 162 CALLBACK(exec, ehdr->e_entry); 163 164 panic("exec returned"); 165 } 166 167 static int 168 elf64_obj_exec(struct preloaded_file *fp) 169 { 170 171 return (EFTYPE); 172 } 173