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   1 /*
   2  *  arch/s390/kernel/early.c
   3  *
   4  *    Copyright IBM Corp. 2007
   5  *    Author(s): Hongjie Yang <hongjie@us.ibm.com>,
   6  *               Heiko Carstens <heiko.carstens@de.ibm.com>
   7  */
   8
   9 #include <linux/init.h>
  10 #include <linux/errno.h>
  11 #include <linux/string.h>
  12 #include <linux/ctype.h>
  13 #include <linux/lockdep.h>
  14 #include <linux/module.h>
  15 #include <linux/pfn.h>
  16 #include <linux/uaccess.h>
  17 #include <asm/ipl.h>
  18 #include <asm/lowcore.h>
  19 #include <asm/processor.h>
  20 #include <asm/sections.h>
  21 #include <asm/setup.h>
  22 #include <asm/cpcmd.h>
  23 #include <asm/sclp.h>
  24 #include "entry.h"
  25
  26 /*
  27  * Create a Kernel NSS if the SAVESYS= parameter is defined
  28  */
  29 #define DEFSYS_CMD_SIZE         96
  30 #define SAVESYS_CMD_SIZE        32
  31
  32 char kernel_nss_name[NSS_NAME_SIZE + 1];
  33
  34 #ifdef CONFIG_SHARED_KERNEL
  35 static noinline __init void create_kernel_nss(void)
  36 {
  37         unsigned int i, stext_pfn, eshared_pfn, end_pfn, min_size;
  38 #ifdef CONFIG_BLK_DEV_INITRD
  39         unsigned int sinitrd_pfn, einitrd_pfn;
  40 #endif
  41         int response;
  42         char *savesys_ptr;
  43         char upper_command_line[COMMAND_LINE_SIZE];
  44         char defsys_cmd[DEFSYS_CMD_SIZE];
  45         char savesys_cmd[SAVESYS_CMD_SIZE];
  46
  47         /* Do nothing if we are not running under VM */
  48         if (!MACHINE_IS_VM)
  49                 return;
  50
  51         /* Convert COMMAND_LINE to upper case */
  52         for (i = 0; i < strlen(COMMAND_LINE); i++)
  53                 upper_command_line[i] = toupper(COMMAND_LINE[i]);
  54
  55         savesys_ptr = strstr(upper_command_line, "SAVESYS=");
  56
  57         if (!savesys_ptr)
  58                 return;
  59
  60         savesys_ptr += 8;    /* Point to the beginning of the NSS name */
  61         for (i = 0; i < NSS_NAME_SIZE; i++) {
  62                 if (savesys_ptr[i] == ' ' || savesys_ptr[i] == '\0')
  63                         break;
  64                 kernel_nss_name[i] = savesys_ptr[i];
  65         }
  66
  67         stext_pfn = PFN_DOWN(__pa(&_stext));
  68         eshared_pfn = PFN_DOWN(__pa(&_eshared));
  69         end_pfn = PFN_UP(__pa(&_end));
  70         min_size = end_pfn << 2;
  71
  72         sprintf(defsys_cmd, "DEFSYS %s 00000-%.5X EW %.5X-%.5X SR %.5X-%.5X",
  73                 kernel_nss_name, stext_pfn - 1, stext_pfn, eshared_pfn - 1,
  74                 eshared_pfn, end_pfn);
  75
  76 #ifdef CONFIG_BLK_DEV_INITRD
  77         if (INITRD_START && INITRD_SIZE) {
  78                 sinitrd_pfn = PFN_DOWN(__pa(INITRD_START));
  79                 einitrd_pfn = PFN_UP(__pa(INITRD_START + INITRD_SIZE));
  80                 min_size = einitrd_pfn << 2;
  81                 sprintf(defsys_cmd, "%s EW %.5X-%.5X", defsys_cmd,
  82                 sinitrd_pfn, einitrd_pfn);
  83         }
  84 #endif
  85
  86         sprintf(defsys_cmd, "%s EW MINSIZE=%.7iK", defsys_cmd, min_size);
  87         sprintf(savesys_cmd, "SAVESYS %s \n IPL %s",
  88                 kernel_nss_name, kernel_nss_name);
  89
  90         __cpcmd(defsys_cmd, NULL, 0, &response);
  91
  92         if (response != 0) {
  93                 kernel_nss_name[0] = '\0';
  94                 return;
  95         }
  96
  97         __cpcmd(savesys_cmd, NULL, 0, &response);
  98
  99         if (response != strlen(savesys_cmd)) {
 100                 kernel_nss_name[0] = '\0';
 101                 return;
 102         }
 103
 104         ipl_flags = IPL_NSS_VALID;
 105 }
 106
 107 #else /* CONFIG_SHARED_KERNEL */
 108
 109 static inline void create_kernel_nss(void) { }
 110
 111 #endif /* CONFIG_SHARED_KERNEL */
 112
 113 /*
 114  * Clear bss memory
 115  */
 116 static noinline __init void clear_bss_section(void)
 117 {
 118         memset(__bss_start, 0, __bss_stop - __bss_start);
 119 }
 120
 121 /*
 122  * Initialize storage key for kernel pages
 123  */
 124 static noinline __init void init_kernel_storage_key(void)
 125 {
 126         unsigned long end_pfn, init_pfn;
 127
 128         end_pfn = PFN_UP(__pa(&_end));
 129
 130         for (init_pfn = 0 ; init_pfn < end_pfn; init_pfn++)
 131                 page_set_storage_key(init_pfn << PAGE_SHIFT, PAGE_DEFAULT_KEY);
 132 }
 133
 134 static noinline __init void detect_machine_type(void)
 135 {
 136         struct cpuinfo_S390 *cpuinfo = &S390_lowcore.cpu_data;
 137
 138         get_cpu_id(&S390_lowcore.cpu_data.cpu_id);
 139
 140         /* Running under z/VM ? */
 141         if (cpuinfo->cpu_id.version == 0xff)
 142                 machine_flags |= 1;
 143
 144         /* Running on a P/390 ? */
 145         if (cpuinfo->cpu_id.machine == 0x7490)
 146                 machine_flags |= 4;
 147 }
 148
 149 #ifdef CONFIG_64BIT
 150 static noinline __init int memory_fast_detect(void)
 151 {
 152         unsigned long val0 = 0;
 153         unsigned long val1 = 0xc;
 154         int ret = -ENOSYS;
 155
 156         if (ipl_flags & IPL_NSS_VALID)
 157                 return -ENOSYS;
 158
 159         asm volatile(
 160                 "       diag    %1,%2,0x260\n"
 161                 "0:     lhi     %0,0\n"
 162                 "1:\n"
 163                 EX_TABLE(0b,1b)
 164                 : "+d" (ret), "+d" (val0), "+d" (val1) : : "cc");
 165
 166         if (ret || val0 != val1)
 167                 return -ENOSYS;
 168
 169         memory_chunk[0].size = val0 + 1;
 170         return 0;
 171 }
 172 #else
 173 static inline int memory_fast_detect(void)
 174 {
 175         return -ENOSYS;
 176 }
 177 #endif
 178
 179 static inline __init unsigned long __tprot(unsigned long addr)
 180 {
 181         int cc = -1;
 182
 183         asm volatile(
 184                 "       tprot   0(%1),0\n"
 185                 "0:     ipm     %0\n"
 186                 "       srl     %0,28\n"
 187                 "1:\n"
 188                 EX_TABLE(0b,1b)
 189                 : "+d" (cc) : "a" (addr) : "cc");
 190         return (unsigned long)cc;
 191 }
 192
 193 /* Checking memory in 128KB increments. */
 194 #define CHUNK_INCR      (1UL << 17)
 195 #define ADDR2G          (1UL << 31)
 196
 197 static noinline __init void find_memory_chunks(unsigned long memsize)
 198 {
 199         unsigned long addr = 0, old_addr = 0;
 200         unsigned long old_cc = CHUNK_READ_WRITE;
 201         unsigned long cc;
 202         int chunk = 0;
 203
 204         while (chunk < MEMORY_CHUNKS) {
 205                 cc = __tprot(addr);
 206                 while (cc == old_cc) {
 207                         addr += CHUNK_INCR;
 208                         if (memsize && addr >= memsize)
 209                                 break;
 210 #ifndef CONFIG_64BIT
 211                         if (addr == ADDR2G)
 212                                 break;
 213 #endif
 214                         cc = __tprot(addr);
 215                 }
 216
 217                 if (old_addr != addr &&
 218                     (old_cc == CHUNK_READ_WRITE || old_cc == CHUNK_READ_ONLY)) {
 219                         memory_chunk[chunk].addr = old_addr;
 220                         memory_chunk[chunk].size = addr - old_addr;
 221                         memory_chunk[chunk].type = old_cc;
 222                         chunk++;
 223                 }
 224
 225                 old_addr = addr;
 226                 old_cc = cc;
 227
 228 #ifndef CONFIG_64BIT
 229                 if (addr == ADDR2G)
 230                         break;
 231 #endif
 232                 /*
 233                  * Finish memory detection at the first hole
 234                  * if storage size is unknown.
 235                  */
 236                 if (cc == -1UL && !memsize)
 237                         break;
 238                 if (memsize && addr >= memsize)
 239                         break;
 240         }
 241 }
 242
 243 static __init void early_pgm_check_handler(void)
 244 {
 245         unsigned long addr;
 246         const struct exception_table_entry *fixup;
 247
 248         addr = S390_lowcore.program_old_psw.addr;
 249         fixup = search_exception_tables(addr & PSW_ADDR_INSN);
 250         if (!fixup)
 251                 disabled_wait(0);
 252         S390_lowcore.program_old_psw.addr = fixup->fixup | PSW_ADDR_AMODE;
 253 }
 254
 255 static noinline __init void setup_lowcore_early(void)
 256 {
 257         psw_t psw;
 258
 259         psw.mask = PSW_BASE_BITS | PSW_DEFAULT_KEY;
 260         psw.addr = PSW_ADDR_AMODE | (unsigned long) s390_base_ext_handler;
 261         S390_lowcore.external_new_psw = psw;
 262         psw.addr = PSW_ADDR_AMODE | (unsigned long) s390_base_pgm_handler;
 263         S390_lowcore.program_new_psw = psw;
 264         s390_base_pgm_handler_fn = early_pgm_check_handler;
 265 }
 266
 267 /*
 268  * Save ipl parameters, clear bss memory, initialize storage keys
 269  * and create a kernel NSS at startup if the SAVESYS= parm is defined
 270  */
 271 void __init startup_init(void)
 272 {
 273         unsigned long long memsize;
 274
 275         ipl_save_parameters();
 276         clear_bss_section();
 277         init_kernel_storage_key();
 278         lockdep_init();
 279         lockdep_off();
 280         detect_machine_type();
 281         create_kernel_nss();
 282         sort_main_extable();
 283         setup_lowcore_early();
 284         sclp_read_info_early();
 285         sclp_facilities_detect();
 286         memsize = sclp_memory_detect();
 287 #ifndef CONFIG_64BIT
 288         /*
 289          * Can't deal with more than 2G in 31 bit addressing mode, so
 290          * limit the value in order to avoid strange side effects.
 291          */
 292         if (memsize > ADDR2G)
 293                 memsize = ADDR2G;
 294 #endif
 295         if (memory_fast_detect() < 0)
 296                 find_memory_chunks((unsigned long) memsize);
 297         lockdep_on();
 298 }