1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/string.h> 3 #include <linux/elf.h> 4 #include <asm/boot_data.h> 5 #include <asm/sections.h> 6 #include <asm/cpu_mf.h> 7 #include <asm/setup.h> 8 #include <asm/kasan.h> 9 #include <asm/kexec.h> 10 #include <asm/sclp.h> 11 #include <asm/diag.h> 12 #include <asm/uv.h> 13 #include "decompressor.h" 14 #include "boot.h" 15 #include "uv.h" 16 17 unsigned long __bootdata_preserved(__kaslr_offset); 18 unsigned long __bootdata(__amode31_base); 19 unsigned long __bootdata_preserved(VMALLOC_START); 20 unsigned long __bootdata_preserved(VMALLOC_END); 21 struct page *__bootdata_preserved(vmemmap); 22 unsigned long __bootdata_preserved(vmemmap_size); 23 unsigned long __bootdata_preserved(MODULES_VADDR); 24 unsigned long __bootdata_preserved(MODULES_END); 25 unsigned long __bootdata(ident_map_size); 26 int __bootdata(is_full_image) = 1; 27 struct initrd_data __bootdata(initrd_data); 28 29 u64 __bootdata_preserved(stfle_fac_list[16]); 30 u64 __bootdata_preserved(alt_stfle_fac_list[16]); 31 struct oldmem_data __bootdata_preserved(oldmem_data); 32 33 void error(char *x) 34 { 35 sclp_early_printk("\n\n"); 36 sclp_early_printk(x); 37 sclp_early_printk("\n\n -- System halted"); 38 39 disabled_wait(); 40 } 41 42 static void setup_lpp(void) 43 { 44 S390_lowcore.current_pid = 0; 45 S390_lowcore.lpp = LPP_MAGIC; 46 if (test_facility(40)) 47 lpp(&S390_lowcore.lpp); 48 } 49 50 #ifdef CONFIG_KERNEL_UNCOMPRESSED 51 unsigned long mem_safe_offset(void) 52 { 53 return vmlinux.default_lma + vmlinux.image_size + vmlinux.bss_size; 54 } 55 #endif 56 57 static void rescue_initrd(unsigned long addr) 58 { 59 if (!IS_ENABLED(CONFIG_BLK_DEV_INITRD)) 60 return; 61 if (!initrd_data.start || !initrd_data.size) 62 return; 63 if (addr <= initrd_data.start) 64 return; 65 memmove((void *)addr, (void *)initrd_data.start, initrd_data.size); 66 initrd_data.start = addr; 67 } 68 69 static void copy_bootdata(void) 70 { 71 if (__boot_data_end - __boot_data_start != vmlinux.bootdata_size) 72 error(".boot.data section size mismatch"); 73 memcpy((void *)vmlinux.bootdata_off, __boot_data_start, vmlinux.bootdata_size); 74 if (__boot_data_preserved_end - __boot_data_preserved_start != vmlinux.bootdata_preserved_size) 75 error(".boot.preserved.data section size mismatch"); 76 memcpy((void *)vmlinux.bootdata_preserved_off, __boot_data_preserved_start, vmlinux.bootdata_preserved_size); 77 } 78 79 static void handle_relocs(unsigned long offset) 80 { 81 Elf64_Rela *rela_start, *rela_end, *rela; 82 int r_type, r_sym, rc; 83 Elf64_Addr loc, val; 84 Elf64_Sym *dynsym; 85 86 rela_start = (Elf64_Rela *) vmlinux.rela_dyn_start; 87 rela_end = (Elf64_Rela *) vmlinux.rela_dyn_end; 88 dynsym = (Elf64_Sym *) vmlinux.dynsym_start; 89 for (rela = rela_start; rela < rela_end; rela++) { 90 loc = rela->r_offset + offset; 91 val = rela->r_addend; 92 r_sym = ELF64_R_SYM(rela->r_info); 93 if (r_sym) { 94 if (dynsym[r_sym].st_shndx != SHN_UNDEF) 95 val += dynsym[r_sym].st_value + offset; 96 } else { 97 /* 98 * 0 == undefined symbol table index (STN_UNDEF), 99 * used for R_390_RELATIVE, only add KASLR offset 100 */ 101 val += offset; 102 } 103 r_type = ELF64_R_TYPE(rela->r_info); 104 rc = arch_kexec_do_relocs(r_type, (void *) loc, val, 0); 105 if (rc) 106 error("Unknown relocation type"); 107 } 108 } 109 110 /* 111 * Merge information from several sources into a single ident_map_size value. 112 * "ident_map_size" represents the upper limit of physical memory we may ever 113 * reach. It might not be all online memory, but also include standby (offline) 114 * memory. "ident_map_size" could be lower then actual standby or even online 115 * memory present, due to limiting factors. We should never go above this limit. 116 * It is the size of our identity mapping. 117 * 118 * Consider the following factors: 119 * 1. max_physmem_end - end of physical memory online or standby. 120 * Always <= end of the last online memory block (get_mem_detect_end()). 121 * 2. CONFIG_MAX_PHYSMEM_BITS - the maximum size of physical memory the 122 * kernel is able to support. 123 * 3. "mem=" kernel command line option which limits physical memory usage. 124 * 4. OLDMEM_BASE which is a kdump memory limit when the kernel is executed as 125 * crash kernel. 126 * 5. "hsa" size which is a memory limit when the kernel is executed during 127 * zfcp/nvme dump. 128 */ 129 static void setup_ident_map_size(unsigned long max_physmem_end) 130 { 131 unsigned long hsa_size; 132 133 ident_map_size = max_physmem_end; 134 if (memory_limit) 135 ident_map_size = min(ident_map_size, memory_limit); 136 ident_map_size = min(ident_map_size, 1UL << MAX_PHYSMEM_BITS); 137 138 #ifdef CONFIG_CRASH_DUMP 139 if (oldmem_data.start) { 140 kaslr_enabled = 0; 141 ident_map_size = min(ident_map_size, oldmem_data.size); 142 } else if (ipl_block_valid && is_ipl_block_dump()) { 143 kaslr_enabled = 0; 144 if (!sclp_early_get_hsa_size(&hsa_size) && hsa_size) 145 ident_map_size = min(ident_map_size, hsa_size); 146 } 147 #endif 148 } 149 150 static void setup_kernel_memory_layout(void) 151 { 152 unsigned long vmemmap_start; 153 unsigned long rte_size; 154 unsigned long pages; 155 156 pages = ident_map_size / PAGE_SIZE; 157 /* vmemmap contains a multiple of PAGES_PER_SECTION struct pages */ 158 vmemmap_size = SECTION_ALIGN_UP(pages) * sizeof(struct page); 159 160 /* choose kernel address space layout: 4 or 3 levels. */ 161 vmemmap_start = round_up(ident_map_size, _REGION3_SIZE); 162 if (IS_ENABLED(CONFIG_KASAN) || 163 vmalloc_size > _REGION2_SIZE || 164 vmemmap_start + vmemmap_size + vmalloc_size + MODULES_LEN > 165 _REGION2_SIZE) { 166 MODULES_END = _REGION1_SIZE; 167 rte_size = _REGION2_SIZE; 168 } else { 169 MODULES_END = _REGION2_SIZE; 170 rte_size = _REGION3_SIZE; 171 } 172 /* 173 * forcing modules and vmalloc area under the ultravisor 174 * secure storage limit, so that any vmalloc allocation 175 * we do could be used to back secure guest storage. 176 */ 177 adjust_to_uv_max(&MODULES_END); 178 #ifdef CONFIG_KASAN 179 /* force vmalloc and modules below kasan shadow */ 180 MODULES_END = min(MODULES_END, KASAN_SHADOW_START); 181 #endif 182 MODULES_VADDR = MODULES_END - MODULES_LEN; 183 VMALLOC_END = MODULES_VADDR; 184 185 /* allow vmalloc area to occupy up to about 1/2 of the rest virtual space left */ 186 vmalloc_size = min(vmalloc_size, round_down(VMALLOC_END / 2, _REGION3_SIZE)); 187 VMALLOC_START = VMALLOC_END - vmalloc_size; 188 189 /* split remaining virtual space between 1:1 mapping & vmemmap array */ 190 pages = VMALLOC_START / (PAGE_SIZE + sizeof(struct page)); 191 pages = SECTION_ALIGN_UP(pages); 192 /* keep vmemmap_start aligned to a top level region table entry */ 193 vmemmap_start = round_down(VMALLOC_START - pages * sizeof(struct page), rte_size); 194 /* vmemmap_start is the future VMEM_MAX_PHYS, make sure it is within MAX_PHYSMEM */ 195 vmemmap_start = min(vmemmap_start, 1UL << MAX_PHYSMEM_BITS); 196 /* make sure identity map doesn't overlay with vmemmap */ 197 ident_map_size = min(ident_map_size, vmemmap_start); 198 vmemmap_size = SECTION_ALIGN_UP(ident_map_size / PAGE_SIZE) * sizeof(struct page); 199 /* make sure vmemmap doesn't overlay with vmalloc area */ 200 VMALLOC_START = max(vmemmap_start + vmemmap_size, VMALLOC_START); 201 vmemmap = (struct page *)vmemmap_start; 202 } 203 204 /* 205 * This function clears the BSS section of the decompressed Linux kernel and NOT the decompressor's. 206 */ 207 static void clear_bss_section(void) 208 { 209 memset((void *)vmlinux.default_lma + vmlinux.image_size, 0, vmlinux.bss_size); 210 } 211 212 /* 213 * Set vmalloc area size to an 8th of (potential) physical memory 214 * size, unless size has been set by kernel command line parameter. 215 */ 216 static void setup_vmalloc_size(void) 217 { 218 unsigned long size; 219 220 if (vmalloc_size_set) 221 return; 222 size = round_up(ident_map_size / 8, _SEGMENT_SIZE); 223 vmalloc_size = max(size, vmalloc_size); 224 } 225 226 static void offset_vmlinux_info(unsigned long offset) 227 { 228 vmlinux.default_lma += offset; 229 *(unsigned long *)(&vmlinux.entry) += offset; 230 vmlinux.bootdata_off += offset; 231 vmlinux.bootdata_preserved_off += offset; 232 vmlinux.rela_dyn_start += offset; 233 vmlinux.rela_dyn_end += offset; 234 vmlinux.dynsym_start += offset; 235 } 236 237 static unsigned long reserve_amode31(unsigned long safe_addr) 238 { 239 __amode31_base = PAGE_ALIGN(safe_addr); 240 return safe_addr + vmlinux.amode31_size; 241 } 242 243 void startup_kernel(void) 244 { 245 unsigned long random_lma; 246 unsigned long safe_addr; 247 void *img; 248 249 initrd_data.start = parmarea.initrd_start; 250 initrd_data.size = parmarea.initrd_size; 251 oldmem_data.start = parmarea.oldmem_base; 252 oldmem_data.size = parmarea.oldmem_size; 253 254 setup_lpp(); 255 store_ipl_parmblock(); 256 safe_addr = mem_safe_offset(); 257 safe_addr = reserve_amode31(safe_addr); 258 safe_addr = read_ipl_report(safe_addr); 259 uv_query_info(); 260 rescue_initrd(safe_addr); 261 sclp_early_read_info(); 262 setup_boot_command_line(); 263 parse_boot_command_line(); 264 sanitize_prot_virt_host(); 265 setup_ident_map_size(detect_memory()); 266 setup_vmalloc_size(); 267 setup_kernel_memory_layout(); 268 269 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && kaslr_enabled) { 270 random_lma = get_random_base(safe_addr); 271 if (random_lma) { 272 __kaslr_offset = random_lma - vmlinux.default_lma; 273 img = (void *)vmlinux.default_lma; 274 offset_vmlinux_info(__kaslr_offset); 275 } 276 } 277 278 if (!IS_ENABLED(CONFIG_KERNEL_UNCOMPRESSED)) { 279 img = decompress_kernel(); 280 memmove((void *)vmlinux.default_lma, img, vmlinux.image_size); 281 } else if (__kaslr_offset) 282 memcpy((void *)vmlinux.default_lma, img, vmlinux.image_size); 283 284 clear_bss_section(); 285 copy_bootdata(); 286 if (IS_ENABLED(CONFIG_RELOCATABLE)) 287 handle_relocs(__kaslr_offset); 288 289 if (__kaslr_offset) { 290 /* 291 * Save KASLR offset for early dumps, before vmcore_info is set. 292 * Mark as uneven to distinguish from real vmcore_info pointer. 293 */ 294 S390_lowcore.vmcore_info = __kaslr_offset | 0x1UL; 295 /* Clear non-relocated kernel */ 296 if (IS_ENABLED(CONFIG_KERNEL_UNCOMPRESSED)) 297 memset(img, 0, vmlinux.image_size); 298 } 299 vmlinux.entry(); 300 } 301