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 void _swsusp_reset_dma(void); 52 unsigned long __bootdata_preserved(__swsusp_reset_dma) = __pa(_swsusp_reset_dma); 53 54 void error(char *x) 55 { 56 sclp_early_printk("\n\n"); 57 sclp_early_printk(x); 58 sclp_early_printk("\n\n -- System halted"); 59 60 disabled_wait(); 61 } 62 63 #ifdef CONFIG_KERNEL_UNCOMPRESSED 64 unsigned long mem_safe_offset(void) 65 { 66 return vmlinux.default_lma + vmlinux.image_size + vmlinux.bss_size; 67 } 68 #endif 69 70 static void rescue_initrd(unsigned long addr) 71 { 72 if (!IS_ENABLED(CONFIG_BLK_DEV_INITRD)) 73 return; 74 if (!INITRD_START || !INITRD_SIZE) 75 return; 76 if (addr <= INITRD_START) 77 return; 78 memmove((void *)addr, (void *)INITRD_START, INITRD_SIZE); 79 INITRD_START = addr; 80 } 81 82 static void copy_bootdata(void) 83 { 84 if (__boot_data_end - __boot_data_start != vmlinux.bootdata_size) 85 error(".boot.data section size mismatch"); 86 memcpy((void *)vmlinux.bootdata_off, __boot_data_start, vmlinux.bootdata_size); 87 if (__boot_data_preserved_end - __boot_data_preserved_start != vmlinux.bootdata_preserved_size) 88 error(".boot.preserved.data section size mismatch"); 89 memcpy((void *)vmlinux.bootdata_preserved_off, __boot_data_preserved_start, vmlinux.bootdata_preserved_size); 90 } 91 92 static void handle_relocs(unsigned long offset) 93 { 94 Elf64_Rela *rela_start, *rela_end, *rela; 95 int r_type, r_sym, rc; 96 Elf64_Addr loc, val; 97 Elf64_Sym *dynsym; 98 99 rela_start = (Elf64_Rela *) vmlinux.rela_dyn_start; 100 rela_end = (Elf64_Rela *) vmlinux.rela_dyn_end; 101 dynsym = (Elf64_Sym *) vmlinux.dynsym_start; 102 for (rela = rela_start; rela < rela_end; rela++) { 103 loc = rela->r_offset + offset; 104 val = rela->r_addend; 105 r_sym = ELF64_R_SYM(rela->r_info); 106 if (r_sym) { 107 if (dynsym[r_sym].st_shndx != SHN_UNDEF) 108 val += dynsym[r_sym].st_value + offset; 109 } else { 110 /* 111 * 0 == undefined symbol table index (STN_UNDEF), 112 * used for R_390_RELATIVE, only add KASLR offset 113 */ 114 val += offset; 115 } 116 r_type = ELF64_R_TYPE(rela->r_info); 117 rc = arch_kexec_do_relocs(r_type, (void *) loc, val, 0); 118 if (rc) 119 error("Unknown relocation type"); 120 } 121 } 122 123 static void clear_bss_section(void) 124 { 125 memset((void *)vmlinux.default_lma + vmlinux.image_size, 0, vmlinux.bss_size); 126 } 127 128 void startup_kernel(void) 129 { 130 unsigned long random_lma; 131 unsigned long safe_addr; 132 void *img; 133 134 store_ipl_parmblock(); 135 safe_addr = mem_safe_offset(); 136 safe_addr = read_ipl_report(safe_addr); 137 uv_query_info(); 138 rescue_initrd(safe_addr); 139 sclp_early_read_info(); 140 setup_boot_command_line(); 141 parse_boot_command_line(); 142 setup_memory_end(); 143 detect_memory(); 144 145 random_lma = __kaslr_offset = 0; 146 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && kaslr_enabled) { 147 random_lma = get_random_base(safe_addr); 148 if (random_lma) { 149 __kaslr_offset = random_lma - vmlinux.default_lma; 150 img = (void *)vmlinux.default_lma; 151 vmlinux.default_lma += __kaslr_offset; 152 vmlinux.entry += __kaslr_offset; 153 vmlinux.bootdata_off += __kaslr_offset; 154 vmlinux.bootdata_preserved_off += __kaslr_offset; 155 vmlinux.rela_dyn_start += __kaslr_offset; 156 vmlinux.rela_dyn_end += __kaslr_offset; 157 vmlinux.dynsym_start += __kaslr_offset; 158 } 159 } 160 161 if (!IS_ENABLED(CONFIG_KERNEL_UNCOMPRESSED)) { 162 img = decompress_kernel(); 163 memmove((void *)vmlinux.default_lma, img, vmlinux.image_size); 164 } else if (__kaslr_offset) 165 memcpy((void *)vmlinux.default_lma, img, vmlinux.image_size); 166 167 clear_bss_section(); 168 copy_bootdata(); 169 if (IS_ENABLED(CONFIG_RELOCATABLE)) 170 handle_relocs(__kaslr_offset); 171 172 if (__kaslr_offset) { 173 /* 174 * Save KASLR offset for early dumps, before vmcore_info is set. 175 * Mark as uneven to distinguish from real vmcore_info pointer. 176 */ 177 S390_lowcore.vmcore_info = __kaslr_offset | 0x1UL; 178 /* Clear non-relocated kernel */ 179 if (IS_ENABLED(CONFIG_KERNEL_UNCOMPRESSED)) 180 memset(img, 0, vmlinux.image_size); 181 } 182 vmlinux.entry(); 183 } 184