xref: /illumos-gate/usr/src/uts/i86pc/dboot/dboot_elfload.c (revision ac2250cb76bb32944fd2c8a3ba2cd3f79747748d)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*
28  * Copyright 2020 Joyent, Inc.
29  */
30 
31 #include <sys/types.h>
32 #include <sys/inttypes.h>
33 #include <sys/systm.h>
34 #include <sys/elf.h>
35 #include <sys/elf_notes.h>
36 
37 #include <util/memcpy.h>
38 
39 #include "dboot_xboot.h"
40 #include "dboot_elfload.h"
41 #include "dboot_printf.h"
42 
43 static caddr_t elf_file = 0;
44 
45 #define	PGETBYTES(offset)	((void *)(elf_file + (offset)))
46 
47 static void *
48 getehdr(void)
49 {
50 	uchar_t *ident;
51 	void *hdr = NULL;
52 
53 	ident = PGETBYTES(0);
54 	if (ident == NULL)
55 		dboot_panic("Cannot read kernel ELF header");
56 
57 	if (ident[EI_MAG0] != ELFMAG0 || ident[EI_MAG1] != ELFMAG1 ||
58 	    ident[EI_MAG2] != ELFMAG2 || ident[EI_MAG3] != ELFMAG3)
59 		dboot_panic("not an ELF file!");
60 
61 	if (ident[EI_CLASS] == ELFCLASS32)
62 		hdr = PGETBYTES(0);
63 	else if (ident[EI_CLASS] == ELFCLASS64)
64 		hdr = PGETBYTES(0);
65 	else
66 		dboot_panic("Unknown ELF class");
67 
68 	return (hdr);
69 }
70 
71 
72 /*
73  * parse the elf file for program information
74  */
75 int
76 dboot_elfload64(uintptr_t file_image)
77 {
78 	Elf64_Ehdr *eh;
79 	Elf64_Phdr *phdr;
80 	caddr_t allphdrs;
81 	int i;
82 	paddr_t src;
83 	paddr_t dst;
84 
85 	elf_file = (caddr_t)file_image;
86 
87 	allphdrs = NULL;
88 
89 	eh = getehdr();
90 	if (eh == NULL)
91 		dboot_panic("getehdr() failed");
92 
93 	if (eh->e_type != ET_EXEC)
94 		dboot_panic("not ET_EXEC, e_type = 0x%x", eh->e_type);
95 
96 	if (eh->e_phnum == 0 || eh->e_phoff == 0)
97 		dboot_panic("no program headers");
98 
99 	/*
100 	 * Get the program headers.
101 	 */
102 	allphdrs = PGETBYTES(eh->e_phoff);
103 	if (allphdrs == NULL)
104 		dboot_panic("Failed to get program headers e_phnum = %d",
105 		    eh->e_phnum);
106 
107 	/*
108 	 * Next look for interesting program headers.
109 	 */
110 	for (i = 0; i < eh->e_phnum; i++) {
111 		/*LINTED [ELF program header alignment]*/
112 		phdr = (Elf64_Phdr *)(allphdrs + eh->e_phentsize * i);
113 
114 		/*
115 		 * Dynamically-linked executable.
116 		 * Complain.
117 		 */
118 		if (phdr->p_type == PT_INTERP) {
119 			dboot_printf("warning: PT_INTERP section\n");
120 			continue;
121 		}
122 
123 		/*
124 		 * at this point we only care about PT_LOAD segments
125 		 */
126 		if (phdr->p_type != PT_LOAD)
127 			continue;
128 
129 		if (phdr->p_flags == (PF_R | PF_W) && phdr->p_vaddr == 0) {
130 			dboot_printf("warning: krtld reloc info?\n");
131 			continue;
132 		}
133 
134 		/*
135 		 * If memory size is zero just ignore this header.
136 		 */
137 		if (phdr->p_memsz == 0)
138 			continue;
139 
140 		/*
141 		 * If load address 1:1 then ignore this header.
142 		 */
143 		if (phdr->p_paddr == phdr->p_vaddr) {
144 			if (prom_debug)
145 				dboot_printf("Skipping PT_LOAD segment for "
146 				    "paddr = 0x%lx\n", (ulong_t)phdr->p_paddr);
147 			continue;
148 		}
149 
150 		/*
151 		 * copy the data to kernel area
152 		 */
153 		if (phdr->p_paddr != FOUR_MEG && phdr->p_paddr != 2 * FOUR_MEG)
154 			dboot_panic("Bad paddr for kernel nucleus segment");
155 		src = (uintptr_t)PGETBYTES(phdr->p_offset);
156 		dst = ktext_phys + phdr->p_paddr - FOUR_MEG;
157 		if (prom_debug)
158 			dboot_printf("copying %ld bytes from ELF offset 0x%lx "
159 			    "to physaddr 0x%lx (va=0x%lx)\n",
160 			    (ulong_t)phdr->p_filesz, (ulong_t)phdr->p_offset,
161 			    (ulong_t)dst, (ulong_t)phdr->p_vaddr);
162 		(void) memcpy((void *)(uintptr_t)dst,
163 		    (void *)(uintptr_t)src, (size_t)phdr->p_filesz);
164 
165 		/*
166 		 * Clear space from oversized segments, bss.
167 		 * Note, the bss actual start is
168 		 * P2ROUNDUP(dst + phdr->p_filesz, shdr->sh_addralign),
169 		 * but we can wipe everything from phdr->p_filesz to
170 		 * phdr->p_memsz.
171 		 */
172 		if (phdr->p_filesz < phdr->p_memsz) {
173 			if (prom_debug) {
174 				dboot_printf("zeroing BSS %zu bytes from "
175 				    "physaddr 0x%" PRIx64
176 				    " (end=0x%" PRIx64 ")\n",
177 				    (size_t)(phdr->p_memsz - phdr->p_filesz),
178 				    dst + phdr->p_filesz,
179 				    dst + phdr->p_memsz - 1);
180 			}
181 			(void) memset((void *)(uintptr_t)(dst + phdr->p_filesz),
182 			    0, phdr->p_memsz - phdr->p_filesz);
183 		}
184 	}
185 
186 	/*
187 	 * Ignore the intepreter (or should we die if there is one??)
188 	 */
189 	return (0);
190 }
191