arch/s390/kernel/early.c

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