arch/s390/boot/startup.c

   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 }