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 "compressed/decompressor.h" 14 #include "boot.h" 15 #include "uv.h" 16 17 unsigned long __bootdata_preserved(__kaslr_offset); 18 unsigned long __bootdata_preserved(VMALLOC_START); 19 unsigned long __bootdata_preserved(VMALLOC_END); 20 struct page *__bootdata_preserved(vmemmap); 21 unsigned long __bootdata_preserved(vmemmap_size); 22 unsigned long __bootdata_preserved(MODULES_VADDR); 23 unsigned long __bootdata_preserved(MODULES_END); 24 unsigned long __bootdata(ident_map_size); 25 int __bootdata(is_full_image) = 1; 26 struct initrd_data __bootdata(initrd_data); 27 28 u64 __bootdata_preserved(stfle_fac_list[16]); 29 u64 __bootdata_preserved(alt_stfle_fac_list[16]); 30 struct oldmem_data __bootdata_preserved(oldmem_data); 31 32 void error(char *x) 33 { 34 sclp_early_printk("\n\n"); 35 sclp_early_printk(x); 36 sclp_early_printk("\n\n -- System halted"); 37 38 disabled_wait(); 39 } 40 41 static void setup_lpp(void) 42 { 43 S390_lowcore.current_pid = 0; 44 S390_lowcore.lpp = LPP_MAGIC; 45 if (test_facility(40)) 46 lpp(&S390_lowcore.lpp); 47 } 48 49 #ifdef CONFIG_KERNEL_UNCOMPRESSED 50 unsigned long mem_safe_offset(void) 51 { 52 return vmlinux.default_lma + vmlinux.image_size + vmlinux.bss_size; 53 } 54 #endif 55 56 static void rescue_initrd(unsigned long addr) 57 { 58 if (!IS_ENABLED(CONFIG_BLK_DEV_INITRD)) 59 return; 60 if (!initrd_data.start || !initrd_data.size) 61 return; 62 if (addr <= initrd_data.start) 63 return; 64 memmove((void *)addr, (void *)initrd_data.start, initrd_data.size); 65 initrd_data.start = addr; 66 } 67 68 static void copy_bootdata(void) 69 { 70 if (__boot_data_end - __boot_data_start != vmlinux.bootdata_size) 71 error(".boot.data section size mismatch"); 72 memcpy((void *)vmlinux.bootdata_off, __boot_data_start, vmlinux.bootdata_size); 73 if (__boot_data_preserved_end - __boot_data_preserved_start != vmlinux.bootdata_preserved_size) 74 error(".boot.preserved.data section size mismatch"); 75 memcpy((void *)vmlinux.bootdata_preserved_off, __boot_data_preserved_start, vmlinux.bootdata_preserved_size); 76 } 77 78 static void handle_relocs(unsigned long offset) 79 { 80 Elf64_Rela *rela_start, *rela_end, *rela; 81 int r_type, r_sym, rc; 82 Elf64_Addr loc, val; 83 Elf64_Sym *dynsym; 84 85 rela_start = (Elf64_Rela *) vmlinux.rela_dyn_start; 86 rela_end = (Elf64_Rela *) vmlinux.rela_dyn_end; 87 dynsym = (Elf64_Sym *) vmlinux.dynsym_start; 88 for (rela = rela_start; rela < rela_end; rela++) { 89 loc = rela->r_offset + offset; 90 val = rela->r_addend; 91 r_sym = ELF64_R_SYM(rela->r_info); 92 if (r_sym) { 93 if (dynsym[r_sym].st_shndx != SHN_UNDEF) 94 val += dynsym[r_sym].st_value + offset; 95 } else { 96 /* 97 * 0 == undefined symbol table index (STN_UNDEF), 98 * used for R_390_RELATIVE, only add KASLR offset 99 */ 100 val += offset; 101 } 102 r_type = ELF64_R_TYPE(rela->r_info); 103 rc = arch_kexec_do_relocs(r_type, (void *) loc, val, 0); 104 if (rc) 105 error("Unknown relocation type"); 106 } 107 } 108 109 /* 110 * Merge information from several sources into a single ident_map_size value. 111 * "ident_map_size" represents the upper limit of physical memory we may ever 112 * reach. It might not be all online memory, but also include standby (offline) 113 * memory. "ident_map_size" could be lower then actual standby or even online 114 * memory present, due to limiting factors. We should never go above this limit. 115 * It is the size of our identity mapping. 116 * 117 * Consider the following factors: 118 * 1. max_physmem_end - end of physical memory online or standby. 119 * Always <= end of the last online memory block (get_mem_detect_end()). 120 * 2. CONFIG_MAX_PHYSMEM_BITS - the maximum size of physical memory the 121 * kernel is able to support. 122 * 3. "mem=" kernel command line option which limits physical memory usage. 123 * 4. OLDMEM_BASE which is a kdump memory limit when the kernel is executed as 124 * crash kernel. 125 * 5. "hsa" size which is a memory limit when the kernel is executed during 126 * zfcp/nvme dump. 127 */ 128 static void setup_ident_map_size(unsigned long max_physmem_end) 129 { 130 unsigned long hsa_size; 131 132 ident_map_size = max_physmem_end; 133 if (memory_limit) 134 ident_map_size = min(ident_map_size, memory_limit); 135 ident_map_size = min(ident_map_size, 1UL << MAX_PHYSMEM_BITS); 136 137 #ifdef CONFIG_CRASH_DUMP 138 if (oldmem_data.start) { 139 kaslr_enabled = 0; 140 ident_map_size = min(ident_map_size, oldmem_data.size); 141 } else if (ipl_block_valid && is_ipl_block_dump()) { 142 kaslr_enabled = 0; 143 if (!sclp_early_get_hsa_size(&hsa_size) && hsa_size) 144 ident_map_size = min(ident_map_size, hsa_size); 145 } 146 #endif 147 } 148 149 static void setup_kernel_memory_layout(void) 150 { 151 bool vmalloc_size_verified = false; 152 unsigned long vmemmap_off; 153 unsigned long vspace_left; 154 unsigned long rte_size; 155 unsigned long pages; 156 unsigned long vmax; 157 158 pages = ident_map_size / PAGE_SIZE; 159 /* vmemmap contains a multiple of PAGES_PER_SECTION struct pages */ 160 vmemmap_size = SECTION_ALIGN_UP(pages) * sizeof(struct page); 161 162 /* choose kernel address space layout: 4 or 3 levels. */ 163 vmemmap_off = round_up(ident_map_size, _REGION3_SIZE); 164 if (IS_ENABLED(CONFIG_KASAN) || 165 vmalloc_size > _REGION2_SIZE || 166 vmemmap_off + vmemmap_size + vmalloc_size + MODULES_LEN > _REGION2_SIZE) 167 vmax = _REGION1_SIZE; 168 else 169 vmax = _REGION2_SIZE; 170 171 /* keep vmemmap_off aligned to a top level region table entry */ 172 rte_size = vmax == _REGION1_SIZE ? _REGION2_SIZE : _REGION3_SIZE; 173 MODULES_END = vmax; 174 if (is_prot_virt_host()) { 175 /* 176 * forcing modules and vmalloc area under the ultravisor 177 * secure storage limit, so that any vmalloc allocation 178 * we do could be used to back secure guest storage. 179 */ 180 adjust_to_uv_max(&MODULES_END); 181 } 182 183 #ifdef CONFIG_KASAN 184 if (MODULES_END < vmax) { 185 /* force vmalloc and modules below kasan shadow */ 186 MODULES_END = min(MODULES_END, KASAN_SHADOW_START); 187 } else { 188 /* 189 * leave vmalloc and modules above kasan shadow but make 190 * sure they don't overlap with it 191 */ 192 vmalloc_size = min(vmalloc_size, vmax - KASAN_SHADOW_END - MODULES_LEN); 193 vmalloc_size_verified = true; 194 vspace_left = KASAN_SHADOW_START; 195 } 196 #endif 197 MODULES_VADDR = MODULES_END - MODULES_LEN; 198 VMALLOC_END = MODULES_VADDR; 199 200 if (vmalloc_size_verified) { 201 VMALLOC_START = VMALLOC_END - vmalloc_size; 202 } else { 203 vmemmap_off = round_up(ident_map_size, rte_size); 204 205 if (vmemmap_off + vmemmap_size > VMALLOC_END || 206 vmalloc_size > VMALLOC_END - vmemmap_off - vmemmap_size) { 207 /* 208 * allow vmalloc area to occupy up to 1/2 of 209 * the rest virtual space left. 210 */ 211 vmalloc_size = min(vmalloc_size, VMALLOC_END / 2); 212 } 213 VMALLOC_START = VMALLOC_END - vmalloc_size; 214 vspace_left = VMALLOC_START; 215 } 216 217 pages = vspace_left / (PAGE_SIZE + sizeof(struct page)); 218 pages = SECTION_ALIGN_UP(pages); 219 vmemmap_off = round_up(vspace_left - pages * sizeof(struct page), rte_size); 220 /* keep vmemmap left most starting from a fresh region table entry */ 221 vmemmap_off = min(vmemmap_off, round_up(ident_map_size, rte_size)); 222 /* take care that identity map is lower then vmemmap */ 223 ident_map_size = min(ident_map_size, vmemmap_off); 224 vmemmap_size = SECTION_ALIGN_UP(ident_map_size / PAGE_SIZE) * sizeof(struct page); 225 VMALLOC_START = max(vmemmap_off + vmemmap_size, VMALLOC_START); 226 vmemmap = (struct page *)vmemmap_off; 227 } 228 229 /* 230 * This function clears the BSS section of the decompressed Linux kernel and NOT the decompressor's. 231 */ 232 static void clear_bss_section(void) 233 { 234 memset((void *)vmlinux.default_lma + vmlinux.image_size, 0, vmlinux.bss_size); 235 } 236 237 /* 238 * Set vmalloc area size to an 8th of (potential) physical memory 239 * size, unless size has been set by kernel command line parameter. 240 */ 241 static void setup_vmalloc_size(void) 242 { 243 unsigned long size; 244 245 if (vmalloc_size_set) 246 return; 247 size = round_up(ident_map_size / 8, _SEGMENT_SIZE); 248 vmalloc_size = max(size, vmalloc_size); 249 } 250 251 static void offset_vmlinux_info(unsigned long offset) 252 { 253 vmlinux.default_lma += offset; 254 *(unsigned long *)(&vmlinux.entry) += offset; 255 vmlinux.bootdata_off += offset; 256 vmlinux.bootdata_preserved_off += offset; 257 vmlinux.rela_dyn_start += offset; 258 vmlinux.rela_dyn_end += offset; 259 vmlinux.dynsym_start += offset; 260 } 261 262 void startup_kernel(void) 263 { 264 unsigned long random_lma; 265 unsigned long safe_addr; 266 void *img; 267 268 initrd_data.start = parmarea.initrd_start; 269 initrd_data.size = parmarea.initrd_size; 270 oldmem_data.start = parmarea.oldmem_base; 271 oldmem_data.size = parmarea.oldmem_size; 272 273 setup_lpp(); 274 store_ipl_parmblock(); 275 safe_addr = mem_safe_offset(); 276 safe_addr = read_ipl_report(safe_addr); 277 uv_query_info(); 278 rescue_initrd(safe_addr); 279 sclp_early_read_info(); 280 setup_boot_command_line(); 281 parse_boot_command_line(); 282 sanitize_prot_virt_host(); 283 setup_ident_map_size(detect_memory()); 284 setup_vmalloc_size(); 285 setup_kernel_memory_layout(); 286 287 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && kaslr_enabled) { 288 random_lma = get_random_base(safe_addr); 289 if (random_lma) { 290 __kaslr_offset = random_lma - vmlinux.default_lma; 291 img = (void *)vmlinux.default_lma; 292 offset_vmlinux_info(__kaslr_offset); 293 } 294 } 295 296 if (!IS_ENABLED(CONFIG_KERNEL_UNCOMPRESSED)) { 297 img = decompress_kernel(); 298 memmove((void *)vmlinux.default_lma, img, vmlinux.image_size); 299 } else if (__kaslr_offset) 300 memcpy((void *)vmlinux.default_lma, img, vmlinux.image_size); 301 302 clear_bss_section(); 303 copy_bootdata(); 304 if (IS_ENABLED(CONFIG_RELOCATABLE)) 305 handle_relocs(__kaslr_offset); 306 307 if (__kaslr_offset) { 308 /* 309 * Save KASLR offset for early dumps, before vmcore_info is set. 310 * Mark as uneven to distinguish from real vmcore_info pointer. 311 */ 312 S390_lowcore.vmcore_info = __kaslr_offset | 0x1UL; 313 /* Clear non-relocated kernel */ 314 if (IS_ENABLED(CONFIG_KERNEL_UNCOMPRESSED)) 315 memset(img, 0, vmlinux.image_size); 316 } 317 vmlinux.entry(); 318 } 319