1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/string.h>
4 #include <asm/boot_data.h>
5 #include <asm/sections.h>
6 #include <asm/maccess.h>
7 #include <asm/cpu_mf.h>
10 #include <asm/kexec.h>
14 #include <asm/abs_lowcore.h>
15 #include <asm/physmem_info.h>
16 #include "decompressor.h"
20 unsigned long __bootdata_preserved(__kaslr_offset);
21 unsigned long __bootdata_preserved(__abs_lowcore);
22 unsigned long __bootdata_preserved(__memcpy_real_area);
23 pte_t *__bootdata_preserved(memcpy_real_ptep);
24 unsigned long __bootdata_preserved(VMALLOC_START);
25 unsigned long __bootdata_preserved(VMALLOC_END);
26 struct page *__bootdata_preserved(vmemmap);
27 unsigned long __bootdata_preserved(vmemmap_size);
28 unsigned long __bootdata_preserved(MODULES_VADDR);
29 unsigned long __bootdata_preserved(MODULES_END);
30 unsigned long __bootdata_preserved(max_mappable);
31 unsigned long __bootdata(ident_map_size);
33 u64 __bootdata_preserved(stfle_fac_list[16]);
34 u64 __bootdata_preserved(alt_stfle_fac_list[16]);
35 struct oldmem_data __bootdata_preserved(oldmem_data);
37 struct machine_info machine;
41 sclp_early_printk("\n\n");
43 sclp_early_printk("\n\n -- System halted");
48 static void detect_facilities(void)
50 if (test_facility(8)) {
51 machine.has_edat1 = 1;
54 if (test_facility(78))
55 machine.has_edat2 = 1;
56 if (test_facility(130))
60 static void setup_lpp(void)
62 S390_lowcore.current_pid = 0;
63 S390_lowcore.lpp = LPP_MAGIC;
64 if (test_facility(40))
65 lpp(&S390_lowcore.lpp);
68 #ifdef CONFIG_KERNEL_UNCOMPRESSED
69 unsigned long mem_safe_offset(void)
71 return vmlinux.default_lma + vmlinux.image_size + vmlinux.bss_size;
75 static void rescue_initrd(unsigned long min, unsigned long max)
77 unsigned long old_addr, addr, size;
79 if (!IS_ENABLED(CONFIG_BLK_DEV_INITRD))
81 if (!get_physmem_reserved(RR_INITRD, &addr, &size))
83 if (addr >= min && addr + size <= max)
86 physmem_free(RR_INITRD);
87 addr = physmem_alloc_top_down(RR_INITRD, size, 0);
88 memmove((void *)addr, (void *)old_addr, size);
91 static void copy_bootdata(void)
93 if (__boot_data_end - __boot_data_start != vmlinux.bootdata_size)
94 error(".boot.data section size mismatch");
95 memcpy((void *)vmlinux.bootdata_off, __boot_data_start, vmlinux.bootdata_size);
96 if (__boot_data_preserved_end - __boot_data_preserved_start != vmlinux.bootdata_preserved_size)
97 error(".boot.preserved.data section size mismatch");
98 memcpy((void *)vmlinux.bootdata_preserved_off, __boot_data_preserved_start, vmlinux.bootdata_preserved_size);
101 static void handle_relocs(unsigned long offset)
103 Elf64_Rela *rela_start, *rela_end, *rela;
104 int r_type, r_sym, rc;
108 rela_start = (Elf64_Rela *) vmlinux.rela_dyn_start;
109 rela_end = (Elf64_Rela *) vmlinux.rela_dyn_end;
110 dynsym = (Elf64_Sym *) vmlinux.dynsym_start;
111 for (rela = rela_start; rela < rela_end; rela++) {
112 loc = rela->r_offset + offset;
113 val = rela->r_addend;
114 r_sym = ELF64_R_SYM(rela->r_info);
116 if (dynsym[r_sym].st_shndx != SHN_UNDEF)
117 val += dynsym[r_sym].st_value + offset;
120 * 0 == undefined symbol table index (STN_UNDEF),
121 * used for R_390_RELATIVE, only add KASLR offset
125 r_type = ELF64_R_TYPE(rela->r_info);
126 rc = arch_kexec_do_relocs(r_type, (void *) loc, val, 0);
128 error("Unknown relocation type");
133 * Merge information from several sources into a single ident_map_size value.
134 * "ident_map_size" represents the upper limit of physical memory we may ever
135 * reach. It might not be all online memory, but also include standby (offline)
136 * memory. "ident_map_size" could be lower then actual standby or even online
137 * memory present, due to limiting factors. We should never go above this limit.
138 * It is the size of our identity mapping.
140 * Consider the following factors:
141 * 1. max_physmem_end - end of physical memory online or standby.
142 * Always >= end of the last online memory range (get_physmem_online_end()).
143 * 2. CONFIG_MAX_PHYSMEM_BITS - the maximum size of physical memory the
144 * kernel is able to support.
145 * 3. "mem=" kernel command line option which limits physical memory usage.
146 * 4. OLDMEM_BASE which is a kdump memory limit when the kernel is executed as
148 * 5. "hsa" size which is a memory limit when the kernel is executed during
151 static void setup_ident_map_size(unsigned long max_physmem_end)
153 unsigned long hsa_size;
155 ident_map_size = max_physmem_end;
157 ident_map_size = min(ident_map_size, memory_limit);
158 ident_map_size = min(ident_map_size, 1UL << MAX_PHYSMEM_BITS);
160 #ifdef CONFIG_CRASH_DUMP
161 if (oldmem_data.start) {
163 ident_map_size = min(ident_map_size, oldmem_data.size);
164 } else if (ipl_block_valid && is_ipl_block_dump()) {
166 if (!sclp_early_get_hsa_size(&hsa_size) && hsa_size)
167 ident_map_size = min(ident_map_size, hsa_size);
172 static unsigned long setup_kernel_memory_layout(void)
174 unsigned long vmemmap_start;
175 unsigned long asce_limit;
176 unsigned long rte_size;
181 pages = ident_map_size / PAGE_SIZE;
182 /* vmemmap contains a multiple of PAGES_PER_SECTION struct pages */
183 vmemmap_size = SECTION_ALIGN_UP(pages) * sizeof(struct page);
185 /* choose kernel address space layout: 4 or 3 levels. */
186 vsize = round_up(ident_map_size, _REGION3_SIZE) + vmemmap_size +
187 MODULES_LEN + MEMCPY_REAL_SIZE + ABS_LOWCORE_MAP_SIZE;
188 vsize = size_add(vsize, vmalloc_size);
189 if (IS_ENABLED(CONFIG_KASAN) || (vsize > _REGION2_SIZE)) {
190 asce_limit = _REGION1_SIZE;
191 rte_size = _REGION2_SIZE;
193 asce_limit = _REGION2_SIZE;
194 rte_size = _REGION3_SIZE;
198 * Forcing modules and vmalloc area under the ultravisor
199 * secure storage limit, so that any vmalloc allocation
200 * we do could be used to back secure guest storage.
202 vmax = adjust_to_uv_max(asce_limit);
204 /* force vmalloc and modules below kasan shadow */
205 vmax = min(vmax, KASAN_SHADOW_START);
207 __memcpy_real_area = round_down(vmax - MEMCPY_REAL_SIZE, PAGE_SIZE);
208 __abs_lowcore = round_down(__memcpy_real_area - ABS_LOWCORE_MAP_SIZE,
209 sizeof(struct lowcore));
210 MODULES_END = round_down(__abs_lowcore, _SEGMENT_SIZE);
211 MODULES_VADDR = MODULES_END - MODULES_LEN;
212 VMALLOC_END = MODULES_VADDR;
214 /* allow vmalloc area to occupy up to about 1/2 of the rest virtual space left */
215 vmalloc_size = min(vmalloc_size, round_down(VMALLOC_END / 2, _REGION3_SIZE));
216 VMALLOC_START = VMALLOC_END - vmalloc_size;
218 /* split remaining virtual space between 1:1 mapping & vmemmap array */
219 pages = VMALLOC_START / (PAGE_SIZE + sizeof(struct page));
220 pages = SECTION_ALIGN_UP(pages);
221 /* keep vmemmap_start aligned to a top level region table entry */
222 vmemmap_start = round_down(VMALLOC_START - pages * sizeof(struct page), rte_size);
223 vmemmap_start = min(vmemmap_start, 1UL << MAX_PHYSMEM_BITS);
224 /* maximum mappable address as seen by arch_get_mappable_range() */
225 max_mappable = vmemmap_start;
226 /* make sure identity map doesn't overlay with vmemmap */
227 ident_map_size = min(ident_map_size, vmemmap_start);
228 vmemmap_size = SECTION_ALIGN_UP(ident_map_size / PAGE_SIZE) * sizeof(struct page);
229 /* make sure vmemmap doesn't overlay with vmalloc area */
230 VMALLOC_START = max(vmemmap_start + vmemmap_size, VMALLOC_START);
231 vmemmap = (struct page *)vmemmap_start;
237 * This function clears the BSS section of the decompressed Linux kernel and NOT the decompressor's.
239 static void clear_bss_section(unsigned long vmlinux_lma)
241 memset((void *)vmlinux_lma + vmlinux.image_size, 0, vmlinux.bss_size);
245 * Set vmalloc area size to an 8th of (potential) physical memory
246 * size, unless size has been set by kernel command line parameter.
248 static void setup_vmalloc_size(void)
252 if (vmalloc_size_set)
254 size = round_up(ident_map_size / 8, _SEGMENT_SIZE);
255 vmalloc_size = max(size, vmalloc_size);
258 static void offset_vmlinux_info(unsigned long offset)
260 *(unsigned long *)(&vmlinux.entry) += offset;
261 vmlinux.bootdata_off += offset;
262 vmlinux.bootdata_preserved_off += offset;
263 vmlinux.rela_dyn_start += offset;
264 vmlinux.rela_dyn_end += offset;
265 vmlinux.dynsym_start += offset;
266 vmlinux.init_mm_off += offset;
267 vmlinux.swapper_pg_dir_off += offset;
268 vmlinux.invalid_pg_dir_off += offset;
270 vmlinux.kasan_early_shadow_page_off += offset;
271 vmlinux.kasan_early_shadow_pte_off += offset;
272 vmlinux.kasan_early_shadow_pmd_off += offset;
273 vmlinux.kasan_early_shadow_pud_off += offset;
274 vmlinux.kasan_early_shadow_p4d_off += offset;
278 void startup_kernel(void)
280 unsigned long max_physmem_end;
281 unsigned long vmlinux_lma = 0;
282 unsigned long amode31_lma = 0;
283 unsigned long asce_limit;
284 unsigned long safe_addr;
289 safe_addr = mem_safe_offset();
292 * Reserve decompressor memory together with decompression heap, buffer and
293 * memory which might be occupied by uncompressed kernel at default 1Mb
294 * position (if KASLR is off or failed).
296 physmem_reserve(RR_DECOMPRESSOR, 0, safe_addr);
297 if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && parmarea.initrd_size)
298 physmem_reserve(RR_INITRD, parmarea.initrd_start, parmarea.initrd_size);
299 oldmem_data.start = parmarea.oldmem_base;
300 oldmem_data.size = parmarea.oldmem_size;
302 store_ipl_parmblock();
305 sclp_early_read_info();
306 setup_boot_command_line();
307 parse_boot_command_line();
309 sanitize_prot_virt_host();
310 max_physmem_end = detect_max_physmem_end();
311 setup_ident_map_size(max_physmem_end);
312 setup_vmalloc_size();
313 asce_limit = setup_kernel_memory_layout();
314 /* got final ident_map_size, physmem allocations could be performed now */
315 physmem_set_usable_limit(ident_map_size);
316 detect_physmem_online_ranges(max_physmem_end);
317 save_ipl_cert_comp_list();
318 rescue_initrd(safe_addr, ident_map_size);
320 if (kaslr_enabled()) {
321 vmlinux_lma = randomize_within_range(vmlinux.image_size + vmlinux.bss_size,
322 THREAD_SIZE, vmlinux.default_lma,
325 __kaslr_offset = vmlinux_lma - vmlinux.default_lma;
326 offset_vmlinux_info(__kaslr_offset);
329 vmlinux_lma = vmlinux_lma ?: vmlinux.default_lma;
330 physmem_reserve(RR_VMLINUX, vmlinux_lma, vmlinux.image_size + vmlinux.bss_size);
332 if (!IS_ENABLED(CONFIG_KERNEL_UNCOMPRESSED)) {
333 img = decompress_kernel();
334 memmove((void *)vmlinux_lma, img, vmlinux.image_size);
335 } else if (__kaslr_offset) {
336 img = (void *)vmlinux.default_lma;
337 memmove((void *)vmlinux_lma, img, vmlinux.image_size);
338 memset(img, 0, vmlinux.image_size);
341 /* vmlinux decompression is done, shrink reserved low memory */
342 physmem_reserve(RR_DECOMPRESSOR, 0, (unsigned long)_decompressor_end);
344 amode31_lma = randomize_within_range(vmlinux.amode31_size, PAGE_SIZE, 0, SZ_2G);
345 amode31_lma = amode31_lma ?: vmlinux.default_lma - vmlinux.amode31_size;
346 physmem_reserve(RR_AMODE31, amode31_lma, vmlinux.amode31_size);
349 * The order of the following operations is important:
351 * - handle_relocs() must follow clear_bss_section() to establish static
352 * memory references to data in .bss to be used by setup_vmem()
355 * - setup_vmem() must follow handle_relocs() to be able using
356 * static memory references to data in .bss (i.e init_mm.pgd)
358 * - copy_bootdata() must follow setup_vmem() to propagate changes to
359 * bootdata made by setup_vmem()
361 clear_bss_section(vmlinux_lma);
362 handle_relocs(__kaslr_offset);
363 setup_vmem(asce_limit);
367 * Save KASLR offset for early dumps, before vmcore_info is set.
368 * Mark as uneven to distinguish from real vmcore_info pointer.
370 S390_lowcore.vmcore_info = __kaslr_offset ? __kaslr_offset | 0x1UL : 0;
373 * Jump to the decompressed kernel entry point and switch DAT mode on.
375 psw.addr = vmlinux.entry;
376 psw.mask = PSW_KERNEL_BITS;