1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/string.h>
3 #include <linux/elf.h>
4 #include <asm/sections.h>
5 #include <asm/setup.h>
6 #include <asm/kexec.h>
7 #include <asm/sclp.h>
8 #include <asm/diag.h>
9 #include <asm/uv.h>
10 #include "compressed/decompressor.h"
11 #include "boot.h"
12
13 extern char __boot_data_start[], __boot_data_end[];
14 extern char __boot_data_preserved_start[], __boot_data_preserved_end[];
15 unsigned long __bootdata_preserved(__kaslr_offset);
16
17 /*
18 * Some code and data needs to stay below 2 GB, even when the kernel would be
19 * relocated above 2 GB, because it has to use 31 bit addresses.
20 * Such code and data is part of the .dma section, and its location is passed
21 * over to the decompressed / relocated kernel via the .boot.preserved.data
22 * section.
23 */
24 extern char _sdma[], _edma[];
25 extern char _stext_dma[], _etext_dma[];
26 extern struct exception_table_entry _start_dma_ex_table[];
27 extern struct exception_table_entry _stop_dma_ex_table[];
28 unsigned long __bootdata_preserved(__sdma) = __pa(&_sdma);
29 unsigned long __bootdata_preserved(__edma) = __pa(&_edma);
30 unsigned long __bootdata_preserved(__stext_dma) = __pa(&_stext_dma);
31 unsigned long __bootdata_preserved(__etext_dma) = __pa(&_etext_dma);
32 struct exception_table_entry *
33 __bootdata_preserved(__start_dma_ex_table) = _start_dma_ex_table;
34 struct exception_table_entry *
35 __bootdata_preserved(__stop_dma_ex_table) = _stop_dma_ex_table;
36
37 int _diag210_dma(struct diag210 *addr);
38 int _diag26c_dma(void *req, void *resp, enum diag26c_sc subcode);
39 int _diag14_dma(unsigned long rx, unsigned long ry1, unsigned long subcode);
40 void _diag0c_dma(struct hypfs_diag0c_entry *entry);
41 void _diag308_reset_dma(void);
42 struct diag_ops __bootdata_preserved(diag_dma_ops) = {
43 .diag210 = _diag210_dma,
44 .diag26c = _diag26c_dma,
45 .diag14 = _diag14_dma,
46 .diag0c = _diag0c_dma,
47 .diag308_reset = _diag308_reset_dma
48 };
49 static struct diag210 _diag210_tmp_dma __section(".dma.data");
50 struct diag210 *__bootdata_preserved(__diag210_tmp_dma) = &_diag210_tmp_dma;
51
error(char * x)52 void error(char *x)
53 {
54 sclp_early_printk("\n\n");
55 sclp_early_printk(x);
56 sclp_early_printk("\n\n -- System halted");
57
58 disabled_wait();
59 }
60
61 #ifdef CONFIG_KERNEL_UNCOMPRESSED
mem_safe_offset(void)62 unsigned long mem_safe_offset(void)
63 {
64 return vmlinux.default_lma + vmlinux.image_size + vmlinux.bss_size;
65 }
66 #endif
67
rescue_initrd(unsigned long addr)68 static void rescue_initrd(unsigned long addr)
69 {
70 if (!IS_ENABLED(CONFIG_BLK_DEV_INITRD))
71 return;
72 if (!INITRD_START || !INITRD_SIZE)
73 return;
74 if (addr <= INITRD_START)
75 return;
76 memmove((void *)addr, (void *)INITRD_START, INITRD_SIZE);
77 INITRD_START = addr;
78 }
79
copy_bootdata(void)80 static void copy_bootdata(void)
81 {
82 if (__boot_data_end - __boot_data_start != vmlinux.bootdata_size)
83 error(".boot.data section size mismatch");
84 memcpy((void *)vmlinux.bootdata_off, __boot_data_start, vmlinux.bootdata_size);
85 if (__boot_data_preserved_end - __boot_data_preserved_start != vmlinux.bootdata_preserved_size)
86 error(".boot.preserved.data section size mismatch");
87 memcpy((void *)vmlinux.bootdata_preserved_off, __boot_data_preserved_start, vmlinux.bootdata_preserved_size);
88 }
89
handle_relocs(unsigned long offset)90 static void handle_relocs(unsigned long offset)
91 {
92 Elf64_Rela *rela_start, *rela_end, *rela;
93 int r_type, r_sym, rc;
94 Elf64_Addr loc, val;
95 Elf64_Sym *dynsym;
96
97 rela_start = (Elf64_Rela *) vmlinux.rela_dyn_start;
98 rela_end = (Elf64_Rela *) vmlinux.rela_dyn_end;
99 dynsym = (Elf64_Sym *) vmlinux.dynsym_start;
100 for (rela = rela_start; rela < rela_end; rela++) {
101 loc = rela->r_offset + offset;
102 val = rela->r_addend;
103 r_sym = ELF64_R_SYM(rela->r_info);
104 if (r_sym) {
105 if (dynsym[r_sym].st_shndx != SHN_UNDEF)
106 val += dynsym[r_sym].st_value + offset;
107 } else {
108 /*
109 * 0 == undefined symbol table index (STN_UNDEF),
110 * used for R_390_RELATIVE, only add KASLR offset
111 */
112 val += offset;
113 }
114 r_type = ELF64_R_TYPE(rela->r_info);
115 rc = arch_kexec_do_relocs(r_type, (void *) loc, val, 0);
116 if (rc)
117 error("Unknown relocation type");
118 }
119 }
120
121 /*
122 * This function clears the BSS section of the decompressed Linux kernel and NOT the decompressor's.
123 */
clear_bss_section(void)124 static void clear_bss_section(void)
125 {
126 memset((void *)vmlinux.default_lma + vmlinux.image_size, 0, vmlinux.bss_size);
127 }
128
startup_kernel(void)129 void startup_kernel(void)
130 {
131 unsigned long random_lma;
132 unsigned long safe_addr;
133 void *img;
134
135 store_ipl_parmblock();
136 safe_addr = mem_safe_offset();
137 safe_addr = read_ipl_report(safe_addr);
138 uv_query_info();
139 rescue_initrd(safe_addr);
140 sclp_early_read_info();
141 setup_boot_command_line();
142 parse_boot_command_line();
143 setup_memory_end();
144 detect_memory();
145
146 random_lma = __kaslr_offset = 0;
147 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && kaslr_enabled) {
148 random_lma = get_random_base(safe_addr);
149 if (random_lma) {
150 __kaslr_offset = random_lma - vmlinux.default_lma;
151 img = (void *)vmlinux.default_lma;
152 vmlinux.default_lma += __kaslr_offset;
153 vmlinux.entry += __kaslr_offset;
154 vmlinux.bootdata_off += __kaslr_offset;
155 vmlinux.bootdata_preserved_off += __kaslr_offset;
156 vmlinux.rela_dyn_start += __kaslr_offset;
157 vmlinux.rela_dyn_end += __kaslr_offset;
158 vmlinux.dynsym_start += __kaslr_offset;
159 }
160 }
161
162 if (!IS_ENABLED(CONFIG_KERNEL_UNCOMPRESSED)) {
163 img = decompress_kernel();
164 memmove((void *)vmlinux.default_lma, img, vmlinux.image_size);
165 } else if (__kaslr_offset)
166 memcpy((void *)vmlinux.default_lma, img, vmlinux.image_size);
167
168 clear_bss_section();
169 copy_bootdata();
170 if (IS_ENABLED(CONFIG_RELOCATABLE))
171 handle_relocs(__kaslr_offset);
172
173 if (__kaslr_offset) {
174 /*
175 * Save KASLR offset for early dumps, before vmcore_info is set.
176 * Mark as uneven to distinguish from real vmcore_info pointer.
177 */
178 S390_lowcore.vmcore_info = __kaslr_offset | 0x1UL;
179 /* Clear non-relocated kernel */
180 if (IS_ENABLED(CONFIG_KERNEL_UNCOMPRESSED))
181 memset(img, 0, vmlinux.image_size);
182 }
183 vmlinux.entry();
184 }
185