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 <asm/abs_lowcore.h>
14 #include "decompressor.h"
15 #include "boot.h"
16 #include "uv.h"
17
18 unsigned long __bootdata_preserved(__kaslr_offset);
19 unsigned long __bootdata_preserved(__abs_lowcore);
20 unsigned long __bootdata_preserved(__memcpy_real_area);
21 unsigned long __bootdata(__amode31_base);
22 unsigned long __bootdata_preserved(VMALLOC_START);
23 unsigned long __bootdata_preserved(VMALLOC_END);
24 struct page *__bootdata_preserved(vmemmap);
25 unsigned long __bootdata_preserved(vmemmap_size);
26 unsigned long __bootdata_preserved(MODULES_VADDR);
27 unsigned long __bootdata_preserved(MODULES_END);
28 unsigned long __bootdata(ident_map_size);
29 int __bootdata(is_full_image) = 1;
30 struct initrd_data __bootdata(initrd_data);
31
32 u64 __bootdata_preserved(stfle_fac_list[16]);
33 u64 __bootdata_preserved(alt_stfle_fac_list[16]);
34 struct oldmem_data __bootdata_preserved(oldmem_data);
35
error(char * x)36 void error(char *x)
37 {
38 sclp_early_printk("\n\n");
39 sclp_early_printk(x);
40 sclp_early_printk("\n\n -- System halted");
41
42 disabled_wait();
43 }
44
setup_lpp(void)45 static void setup_lpp(void)
46 {
47 S390_lowcore.current_pid = 0;
48 S390_lowcore.lpp = LPP_MAGIC;
49 if (test_facility(40))
50 lpp(&S390_lowcore.lpp);
51 }
52
53 #ifdef CONFIG_KERNEL_UNCOMPRESSED
mem_safe_offset(void)54 unsigned long mem_safe_offset(void)
55 {
56 return vmlinux.default_lma + vmlinux.image_size + vmlinux.bss_size;
57 }
58 #endif
59
rescue_initrd(unsigned long addr)60 static void rescue_initrd(unsigned long addr)
61 {
62 if (!IS_ENABLED(CONFIG_BLK_DEV_INITRD))
63 return;
64 if (!initrd_data.start || !initrd_data.size)
65 return;
66 if (addr <= initrd_data.start)
67 return;
68 memmove((void *)addr, (void *)initrd_data.start, initrd_data.size);
69 initrd_data.start = addr;
70 }
71
copy_bootdata(void)72 static void copy_bootdata(void)
73 {
74 if (__boot_data_end - __boot_data_start != vmlinux.bootdata_size)
75 error(".boot.data section size mismatch");
76 memcpy((void *)vmlinux.bootdata_off, __boot_data_start, vmlinux.bootdata_size);
77 if (__boot_data_preserved_end - __boot_data_preserved_start != vmlinux.bootdata_preserved_size)
78 error(".boot.preserved.data section size mismatch");
79 memcpy((void *)vmlinux.bootdata_preserved_off, __boot_data_preserved_start, vmlinux.bootdata_preserved_size);
80 }
81
handle_relocs(unsigned long offset)82 static void handle_relocs(unsigned long offset)
83 {
84 Elf64_Rela *rela_start, *rela_end, *rela;
85 int r_type, r_sym, rc;
86 Elf64_Addr loc, val;
87 Elf64_Sym *dynsym;
88
89 rela_start = (Elf64_Rela *) vmlinux.rela_dyn_start;
90 rela_end = (Elf64_Rela *) vmlinux.rela_dyn_end;
91 dynsym = (Elf64_Sym *) vmlinux.dynsym_start;
92 for (rela = rela_start; rela < rela_end; rela++) {
93 loc = rela->r_offset + offset;
94 val = rela->r_addend;
95 r_sym = ELF64_R_SYM(rela->r_info);
96 if (r_sym) {
97 if (dynsym[r_sym].st_shndx != SHN_UNDEF)
98 val += dynsym[r_sym].st_value + offset;
99 } else {
100 /*
101 * 0 == undefined symbol table index (STN_UNDEF),
102 * used for R_390_RELATIVE, only add KASLR offset
103 */
104 val += offset;
105 }
106 r_type = ELF64_R_TYPE(rela->r_info);
107 rc = arch_kexec_do_relocs(r_type, (void *) loc, val, 0);
108 if (rc)
109 error("Unknown relocation type");
110 }
111 }
112
113 /*
114 * Merge information from several sources into a single ident_map_size value.
115 * "ident_map_size" represents the upper limit of physical memory we may ever
116 * reach. It might not be all online memory, but also include standby (offline)
117 * memory. "ident_map_size" could be lower then actual standby or even online
118 * memory present, due to limiting factors. We should never go above this limit.
119 * It is the size of our identity mapping.
120 *
121 * Consider the following factors:
122 * 1. max_physmem_end - end of physical memory online or standby.
123 * Always <= end of the last online memory block (get_mem_detect_end()).
124 * 2. CONFIG_MAX_PHYSMEM_BITS - the maximum size of physical memory the
125 * kernel is able to support.
126 * 3. "mem=" kernel command line option which limits physical memory usage.
127 * 4. OLDMEM_BASE which is a kdump memory limit when the kernel is executed as
128 * crash kernel.
129 * 5. "hsa" size which is a memory limit when the kernel is executed during
130 * zfcp/nvme dump.
131 */
setup_ident_map_size(unsigned long max_physmem_end)132 static void setup_ident_map_size(unsigned long max_physmem_end)
133 {
134 unsigned long hsa_size;
135
136 ident_map_size = max_physmem_end;
137 if (memory_limit)
138 ident_map_size = min(ident_map_size, memory_limit);
139 ident_map_size = min(ident_map_size, 1UL << MAX_PHYSMEM_BITS);
140
141 #ifdef CONFIG_CRASH_DUMP
142 if (oldmem_data.start) {
143 kaslr_enabled = 0;
144 ident_map_size = min(ident_map_size, oldmem_data.size);
145 } else if (ipl_block_valid && is_ipl_block_dump()) {
146 kaslr_enabled = 0;
147 if (!sclp_early_get_hsa_size(&hsa_size) && hsa_size)
148 ident_map_size = min(ident_map_size, hsa_size);
149 }
150 #endif
151 }
152
setup_kernel_memory_layout(void)153 static void setup_kernel_memory_layout(void)
154 {
155 unsigned long vmemmap_start;
156 unsigned long rte_size;
157 unsigned long pages;
158 unsigned long vmax;
159
160 pages = ident_map_size / PAGE_SIZE;
161 /* vmemmap contains a multiple of PAGES_PER_SECTION struct pages */
162 vmemmap_size = SECTION_ALIGN_UP(pages) * sizeof(struct page);
163
164 /* choose kernel address space layout: 4 or 3 levels. */
165 vmemmap_start = round_up(ident_map_size, _REGION3_SIZE);
166 if (IS_ENABLED(CONFIG_KASAN) ||
167 vmalloc_size > _REGION2_SIZE ||
168 vmemmap_start + vmemmap_size + vmalloc_size + MODULES_LEN >
169 _REGION2_SIZE) {
170 vmax = _REGION1_SIZE;
171 rte_size = _REGION2_SIZE;
172 } else {
173 vmax = _REGION2_SIZE;
174 rte_size = _REGION3_SIZE;
175 }
176 /*
177 * forcing modules and vmalloc area under the ultravisor
178 * secure storage limit, so that any vmalloc allocation
179 * we do could be used to back secure guest storage.
180 */
181 vmax = adjust_to_uv_max(vmax);
182 #ifdef CONFIG_KASAN
183 /* force vmalloc and modules below kasan shadow */
184 vmax = min(vmax, KASAN_SHADOW_START);
185 #endif
186 __memcpy_real_area = round_down(vmax - PAGE_SIZE, PAGE_SIZE);
187 __abs_lowcore = round_down(__memcpy_real_area - ABS_LOWCORE_MAP_SIZE,
188 sizeof(struct lowcore));
189 MODULES_END = round_down(__abs_lowcore, _SEGMENT_SIZE);
190 MODULES_VADDR = MODULES_END - MODULES_LEN;
191 VMALLOC_END = MODULES_VADDR;
192
193 /* allow vmalloc area to occupy up to about 1/2 of the rest virtual space left */
194 vmalloc_size = min(vmalloc_size, round_down(VMALLOC_END / 2, _REGION3_SIZE));
195 VMALLOC_START = VMALLOC_END - vmalloc_size;
196
197 /* split remaining virtual space between 1:1 mapping & vmemmap array */
198 pages = VMALLOC_START / (PAGE_SIZE + sizeof(struct page));
199 pages = SECTION_ALIGN_UP(pages);
200 /* keep vmemmap_start aligned to a top level region table entry */
201 vmemmap_start = round_down(VMALLOC_START - pages * sizeof(struct page), rte_size);
202 /* vmemmap_start is the future VMEM_MAX_PHYS, make sure it is within MAX_PHYSMEM */
203 vmemmap_start = min(vmemmap_start, 1UL << MAX_PHYSMEM_BITS);
204 /* make sure identity map doesn't overlay with vmemmap */
205 ident_map_size = min(ident_map_size, vmemmap_start);
206 vmemmap_size = SECTION_ALIGN_UP(ident_map_size / PAGE_SIZE) * sizeof(struct page);
207 /* make sure vmemmap doesn't overlay with vmalloc area */
208 VMALLOC_START = max(vmemmap_start + vmemmap_size, VMALLOC_START);
209 vmemmap = (struct page *)vmemmap_start;
210 }
211
212 /*
213 * This function clears the BSS section of the decompressed Linux kernel and NOT the decompressor's.
214 */
clear_bss_section(void)215 static void clear_bss_section(void)
216 {
217 memset((void *)vmlinux.default_lma + vmlinux.image_size, 0, vmlinux.bss_size);
218 }
219
220 /*
221 * Set vmalloc area size to an 8th of (potential) physical memory
222 * size, unless size has been set by kernel command line parameter.
223 */
setup_vmalloc_size(void)224 static void setup_vmalloc_size(void)
225 {
226 unsigned long size;
227
228 if (vmalloc_size_set)
229 return;
230 size = round_up(ident_map_size / 8, _SEGMENT_SIZE);
231 vmalloc_size = max(size, vmalloc_size);
232 }
233
offset_vmlinux_info(unsigned long offset)234 static void offset_vmlinux_info(unsigned long offset)
235 {
236 vmlinux.default_lma += offset;
237 *(unsigned long *)(&vmlinux.entry) += offset;
238 vmlinux.bootdata_off += offset;
239 vmlinux.bootdata_preserved_off += offset;
240 vmlinux.rela_dyn_start += offset;
241 vmlinux.rela_dyn_end += offset;
242 vmlinux.dynsym_start += offset;
243 }
244
reserve_amode31(unsigned long safe_addr)245 static unsigned long reserve_amode31(unsigned long safe_addr)
246 {
247 __amode31_base = PAGE_ALIGN(safe_addr);
248 return safe_addr + vmlinux.amode31_size;
249 }
250
startup_kernel(void)251 void startup_kernel(void)
252 {
253 unsigned long random_lma;
254 unsigned long safe_addr;
255 void *img;
256
257 initrd_data.start = parmarea.initrd_start;
258 initrd_data.size = parmarea.initrd_size;
259 oldmem_data.start = parmarea.oldmem_base;
260 oldmem_data.size = parmarea.oldmem_size;
261
262 setup_lpp();
263 store_ipl_parmblock();
264 safe_addr = mem_safe_offset();
265 safe_addr = reserve_amode31(safe_addr);
266 safe_addr = read_ipl_report(safe_addr);
267 uv_query_info();
268 rescue_initrd(safe_addr);
269 sclp_early_read_info();
270 setup_boot_command_line();
271 parse_boot_command_line();
272 sanitize_prot_virt_host();
273 setup_ident_map_size(detect_memory());
274 setup_vmalloc_size();
275 setup_kernel_memory_layout();
276
277 if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && kaslr_enabled) {
278 random_lma = get_random_base(safe_addr);
279 if (random_lma) {
280 __kaslr_offset = random_lma - vmlinux.default_lma;
281 img = (void *)vmlinux.default_lma;
282 offset_vmlinux_info(__kaslr_offset);
283 }
284 }
285
286 if (!IS_ENABLED(CONFIG_KERNEL_UNCOMPRESSED)) {
287 img = decompress_kernel();
288 memmove((void *)vmlinux.default_lma, img, vmlinux.image_size);
289 } else if (__kaslr_offset)
290 memcpy((void *)vmlinux.default_lma, img, vmlinux.image_size);
291
292 clear_bss_section();
293 copy_bootdata();
294 handle_relocs(__kaslr_offset);
295
296 if (__kaslr_offset) {
297 /*
298 * Save KASLR offset for early dumps, before vmcore_info is set.
299 * Mark as uneven to distinguish from real vmcore_info pointer.
300 */
301 S390_lowcore.vmcore_info = __kaslr_offset | 0x1UL;
302 /* Clear non-relocated kernel */
303 if (IS_ENABLED(CONFIG_KERNEL_UNCOMPRESSED))
304 memset(img, 0, vmlinux.image_size);
305 }
306 vmlinux.entry();
307 }
308
