arch/x86/kernel/head_32.S

   1 /*
   2  *
   3  *  Copyright (C) 1991, 1992  Linus Torvalds
   4  *
   5  *  Enhanced CPU detection and feature setting code by Mike Jagdis
   6  *  and Martin Mares, November 1997.
   7  */
   8
   9 .text
  10 #include <linux/threads.h>
  11 #include <linux/init.h>
  12 #include <linux/linkage.h>
  13 #include <asm/segment.h>
  14 #include <asm/page.h>
  15 #include <asm/pgtable.h>
  16 #include <asm/desc.h>
  17 #include <asm/cache.h>
  18 #include <asm/thread_info.h>
  19 #include <asm/asm-offsets.h>
  20 #include <asm/setup.h>
  21 #include <asm/processor-flags.h>
  22
  23 /* Physical address */
  24 #define pa(X) ((X) - __PAGE_OFFSET)
  25
  26 /*
  27  * References to members of the new_cpu_data structure.
  28  */
  29
  30 #define X86             new_cpu_data+CPUINFO_x86
  31 #define X86_VENDOR      new_cpu_data+CPUINFO_x86_vendor
  32 #define X86_MODEL       new_cpu_data+CPUINFO_x86_model
  33 #define X86_MASK        new_cpu_data+CPUINFO_x86_mask
  34 #define X86_HARD_MATH   new_cpu_data+CPUINFO_hard_math
  35 #define X86_CPUID       new_cpu_data+CPUINFO_cpuid_level
  36 #define X86_CAPABILITY  new_cpu_data+CPUINFO_x86_capability
  37 #define X86_VENDOR_ID   new_cpu_data+CPUINFO_x86_vendor_id
  38
  39 /*
  40  * This is how much memory *in addition to the memory covered up to
  41  * and including _end* we need mapped initially.
  42  * We need:
  43  *  - one bit for each possible page, but only in low memory, which means
  44  *     2^32/4096/8 = 128K worst case (4G/4G split.)
  45  *  - enough space to map all low memory, which means
  46  *     (2^32/4096) / 1024 pages (worst case, non PAE)
  47  *     (2^32/4096) / 512 + 4 pages (worst case for PAE)
  48  *  - a few pages for allocator use before the kernel pagetable has
  49  *     been set up
  50  *
  51  * Modulo rounding, each megabyte assigned here requires a kilobyte of
  52  * memory, which is currently unreclaimed.
  53  *
  54  * This should be a multiple of a page.
  55  */
  56 LOW_PAGES = 1<<(32-PAGE_SHIFT_asm)
  57
  58 /*
  59  * To preserve the DMA pool in PAGEALLOC kernels, we'll allocate
  60  * pagetables from above the 16MB DMA limit, so we'll have to set
  61  * up pagetables 16MB more (worst-case):
  62  */
  63 #ifdef CONFIG_DEBUG_PAGEALLOC
  64 LOW_PAGES = LOW_PAGES + 0x1000000
  65 #endif
  66
  67 #if PTRS_PER_PMD > 1
  68 PAGE_TABLE_SIZE = (LOW_PAGES / PTRS_PER_PMD) + PTRS_PER_PGD
  69 #else
  70 PAGE_TABLE_SIZE = (LOW_PAGES / PTRS_PER_PGD)
  71 #endif
  72 BOOTBITMAP_SIZE = LOW_PAGES / 8
  73 ALLOCATOR_SLOP = 4
  74
  75 INIT_MAP_BEYOND_END = BOOTBITMAP_SIZE + (PAGE_TABLE_SIZE + ALLOCATOR_SLOP)*PAGE_SIZE_asm
  76
  77 /*
  78  * 32-bit kernel entrypoint; only used by the boot CPU.  On entry,
  79  * %esi points to the real-mode code as a 32-bit pointer.
  80  * CS and DS must be 4 GB flat segments, but we don't depend on
  81  * any particular GDT layout, because we load our own as soon as we
  82  * can.
  83  */
  84 .section .text.head,"ax",@progbits
  85 ENTRY(startup_32)
  86         /* test KEEP_SEGMENTS flag to see if the bootloader is asking
  87                 us to not reload segments */
  88         testb $(1<<6), BP_loadflags(%esi)
  89         jnz 2f
  90
  91 /*
  92  * Set segments to known values.
  93  */
  94         lgdt pa(boot_gdt_descr)
  95         movl $(__BOOT_DS),%eax
  96         movl %eax,%ds
  97         movl %eax,%es
  98         movl %eax,%fs
  99         movl %eax,%gs
 100 2:
 101
 102 /*
 103  * Clear BSS first so that there are no surprises...
 104  */
 105         cld
 106         xorl %eax,%eax
 107         movl $pa(__bss_start),%edi
 108         movl $pa(__bss_stop),%ecx
 109         subl %edi,%ecx
 110         shrl $2,%ecx
 111         rep ; stosl
 112 /*
 113  * Copy bootup parameters out of the way.
 114  * Note: %esi still has the pointer to the real-mode data.
 115  * With the kexec as boot loader, parameter segment might be loaded beyond
 116  * kernel image and might not even be addressable by early boot page tables.
 117  * (kexec on panic case). Hence copy out the parameters before initializing
 118  * page tables.
 119  */
 120         movl $pa(boot_params),%edi
 121         movl $(PARAM_SIZE/4),%ecx
 122         cld
 123         rep
 124         movsl
 125         movl pa(boot_params) + NEW_CL_POINTER,%esi
 126         andl %esi,%esi
 127         jz 1f                   # No comand line
 128         movl $pa(boot_command_line),%edi
 129         movl $(COMMAND_LINE_SIZE/4),%ecx
 130         rep
 131         movsl
 132 1:
 133
 134 #ifdef CONFIG_PARAVIRT
 135         /* This is can only trip for a broken bootloader... */
 136         cmpw $0x207, pa(boot_params + BP_version)
 137         jb default_entry
 138
 139         /* Paravirt-compatible boot parameters.  Look to see what architecture
 140                 we're booting under. */
 141         movl pa(boot_params + BP_hardware_subarch), %eax
 142         cmpl $num_subarch_entries, %eax
 143         jae bad_subarch
 144
 145         movl pa(subarch_entries)(,%eax,4), %eax
 146         subl $__PAGE_OFFSET, %eax
 147         jmp *%eax
 148
 149 bad_subarch:
 150 WEAK(lguest_entry)
 151 WEAK(xen_entry)
 152         /* Unknown implementation; there's really
 153            nothing we can do at this point. */
 154         ud2a
 155
 156         __INITDATA
 157
 158 subarch_entries:
 159         .long default_entry             /* normal x86/PC */
 160         .long lguest_entry              /* lguest hypervisor */
 161         .long xen_entry                 /* Xen hypervisor */
 162 num_subarch_entries = (. - subarch_entries) / 4
 163 .previous
 164 #endif /* CONFIG_PARAVIRT */
 165
 166 /*
 167  * Initialize page tables.  This creates a PDE and a set of page
 168  * tables, which are located immediately beyond _end.  The variable
 169  * init_pg_tables_end is set up to point to the first "safe" location.
 170  * Mappings are created both at virtual address 0 (identity mapping)
 171  * and PAGE_OFFSET for up to _end+sizeof(page tables)+INIT_MAP_BEYOND_END.
 172  *
 173  * Note that the stack is not yet set up!
 174  */
 175 default_entry:
 176 #ifdef CONFIG_X86_PAE
 177
 178         /*
 179          * In PAE mode swapper_pg_dir is statically defined to contain enough
 180          * entries to cover the VMSPLIT option (that is the top 1, 2 or 3
 181          * entries). The identity mapping is handled by pointing two PGD
 182          * entries to the first kernel PMD.
 183          *
 184          * Note the upper half of each PMD or PTE are always zero at
 185          * this stage.
 186          */
 187
 188 #define KPMDS (((-__PAGE_OFFSET) >> 30) & 3) /* Number of kernel PMDs */
 189
 190         xorl %ebx,%ebx                          /* %ebx is kept at zero */
 191
 192         movl $pa(pg0), %edi
 193         movl %edi, pa(init_pg_tables_start)
 194         movl $pa(swapper_pg_pmd), %edx
 195         movl $PTE_IDENT_ATTR, %eax
 196 10:
 197         leal PDE_IDENT_ATTR(%edi),%ecx          /* Create PMD entry */
 198         movl %ecx,(%edx)                        /* Store PMD entry */
 199                                                 /* Upper half already zero */
 200         addl $8,%edx
 201         movl $512,%ecx
 202 11:
 203         stosl
 204         xchgl %eax,%ebx
 205         stosl
 206         xchgl %eax,%ebx
 207         addl $0x1000,%eax
 208         loop 11b
 209
 210         /*
 211          * End condition: we must map up to and including INIT_MAP_BEYOND_END
 212          * bytes beyond the end of our own page tables.
 213          */
 214         leal (INIT_MAP_BEYOND_END+PTE_IDENT_ATTR)(%edi),%ebp
 215         cmpl %ebp,%eax
 216         jb 10b
 217 1:
 218         movl %edi,pa(init_pg_tables_end)
 219         shrl $12, %eax
 220         movl %eax, pa(max_pfn_mapped)
 221
 222         /* Do early initialization of the fixmap area */
 223         movl $pa(swapper_pg_fixmap)+PDE_IDENT_ATTR,%eax
 224         movl %eax,pa(swapper_pg_pmd+0x1000*KPMDS-8)
 225 #else   /* Not PAE */
 226
 227 page_pde_offset = (__PAGE_OFFSET >> 20);
 228
 229         movl $pa(pg0), %edi
 230         movl %edi, pa(init_pg_tables_start)
 231         movl $pa(swapper_pg_dir), %edx
 232         movl $PTE_IDENT_ATTR, %eax
 233 10:
 234         leal PDE_IDENT_ATTR(%edi),%ecx          /* Create PDE entry */
 235         movl %ecx,(%edx)                        /* Store identity PDE entry */
 236         movl %ecx,page_pde_offset(%edx)         /* Store kernel PDE entry */
 237         addl $4,%edx
 238         movl $1024, %ecx
 239 11:
 240         stosl
 241         addl $0x1000,%eax
 242         loop 11b
 243         /*
 244          * End condition: we must map up to and including INIT_MAP_BEYOND_END
 245          * bytes beyond the end of our own page tables; the +0x007 is
 246          * the attribute bits
 247          */
 248         leal (INIT_MAP_BEYOND_END+PTE_IDENT_ATTR)(%edi),%ebp
 249         cmpl %ebp,%eax
 250         jb 10b
 251         movl %edi,pa(init_pg_tables_end)
 252         shrl $12, %eax
 253         movl %eax, pa(max_pfn_mapped)
 254
 255         /* Do early initialization of the fixmap area */
 256         movl $pa(swapper_pg_fixmap)+PDE_IDENT_ATTR,%eax
 257         movl %eax,pa(swapper_pg_dir+0xffc)
 258 #endif
 259         jmp 3f
 260 /*
 261  * Non-boot CPU entry point; entered from trampoline.S
 262  * We can't lgdt here, because lgdt itself uses a data segment, but
 263  * we know the trampoline has already loaded the boot_gdt for us.
 264  *
 265  * If cpu hotplug is not supported then this code can go in init section
 266  * which will be freed later
 267  */
 268
 269 #ifndef CONFIG_HOTPLUG_CPU
 270 .section .init.text,"ax",@progbits
 271 #endif
 272
 273 #ifdef CONFIG_SMP
 274 ENTRY(startup_32_smp)
 275         cld
 276         movl $(__BOOT_DS),%eax
 277         movl %eax,%ds
 278         movl %eax,%es
 279         movl %eax,%fs
 280         movl %eax,%gs
 281 #endif /* CONFIG_SMP */
 282 3:
 283
 284 /*
 285  *      New page tables may be in 4Mbyte page mode and may
 286  *      be using the global pages.
 287  *
 288  *      NOTE! If we are on a 486 we may have no cr4 at all!
 289  *      So we do not try to touch it unless we really have
 290  *      some bits in it to set.  This won't work if the BSP
 291  *      implements cr4 but this AP does not -- very unlikely
 292  *      but be warned!  The same applies to the pse feature
 293  *      if not equally supported. --macro
 294  *
 295  *      NOTE! We have to correct for the fact that we're
 296  *      not yet offset PAGE_OFFSET..
 297  */
 298 #define cr4_bits pa(mmu_cr4_features)
 299         movl cr4_bits,%edx
 300         andl %edx,%edx
 301         jz 6f
 302         movl %cr4,%eax          # Turn on paging options (PSE,PAE,..)
 303         orl %edx,%eax
 304         movl %eax,%cr4
 305
 306         btl $5, %eax            # check if PAE is enabled
 307         jnc 6f
 308
 309         /* Check if extended functions are implemented */
 310         movl $0x80000000, %eax
 311         cpuid
 312         cmpl $0x80000000, %eax
 313         jbe 6f
 314         mov $0x80000001, %eax
 315         cpuid
 316         /* Execute Disable bit supported? */
 317         btl $20, %edx
 318         jnc 6f
 319
 320         /* Setup EFER (Extended Feature Enable Register) */
 321         movl $0xc0000080, %ecx
 322         rdmsr
 323
 324         btsl $11, %eax
 325         /* Make changes effective */
 326         wrmsr
 327
 328 6:
 329
 330 /*
 331  * Enable paging
 332  */
 333         movl $pa(swapper_pg_dir),%eax
 334         movl %eax,%cr3          /* set the page table pointer.. */
 335         movl %cr0,%eax
 336         orl  $X86_CR0_PG,%eax
 337         movl %eax,%cr0          /* ..and set paging (PG) bit */
 338         ljmp $__BOOT_CS,$1f     /* Clear prefetch and normalize %eip */
 339 1:
 340         /* Set up the stack pointer */
 341         lss stack_start,%esp
 342
 343 /*
 344  * Initialize eflags.  Some BIOS's leave bits like NT set.  This would
 345  * confuse the debugger if this code is traced.
 346  * XXX - best to initialize before switching to protected mode.
 347  */
 348         pushl $0
 349         popfl
 350
 351 #ifdef CONFIG_SMP
 352         cmpb $0, ready
 353         jz  1f                          /* Initial CPU cleans BSS */
 354         jmp checkCPUtype
 355 1:
 356 #endif /* CONFIG_SMP */
 357
 358 /*
 359  * start system 32-bit setup. We need to re-do some of the things done
 360  * in 16-bit mode for the "real" operations.
 361  */
 362         call setup_idt
 363
 364 checkCPUtype:
 365
 366         movl $-1,X86_CPUID              #  -1 for no CPUID initially
 367
 368 /* check if it is 486 or 386. */
 369 /*
 370  * XXX - this does a lot of unnecessary setup.  Alignment checks don't
 371  * apply at our cpl of 0 and the stack ought to be aligned already, and
 372  * we don't need to preserve eflags.
 373  */
 374
 375         movb $3,X86             # at least 386
 376         pushfl                  # push EFLAGS
 377         popl %eax               # get EFLAGS
 378         movl %eax,%ecx          # save original EFLAGS
 379         xorl $0x240000,%eax     # flip AC and ID bits in EFLAGS
 380         pushl %eax              # copy to EFLAGS
 381         popfl                   # set EFLAGS
 382         pushfl                  # get new EFLAGS
 383         popl %eax               # put it in eax
 384         xorl %ecx,%eax          # change in flags
 385         pushl %ecx              # restore original EFLAGS
 386         popfl
 387         testl $0x40000,%eax     # check if AC bit changed
 388         je is386
 389
 390         movb $4,X86             # at least 486
 391         testl $0x200000,%eax    # check if ID bit changed
 392         je is486
 393
 394         /* get vendor info */
 395         xorl %eax,%eax                  # call CPUID with 0 -> return vendor ID
 396         cpuid
 397         movl %eax,X86_CPUID             # save CPUID level
 398         movl %ebx,X86_VENDOR_ID         # lo 4 chars
 399         movl %edx,X86_VENDOR_ID+4       # next 4 chars
 400         movl %ecx,X86_VENDOR_ID+8       # last 4 chars
 401
 402         orl %eax,%eax                   # do we have processor info as well?
 403         je is486
 404
 405         movl $1,%eax            # Use the CPUID instruction to get CPU type
 406         cpuid
 407         movb %al,%cl            # save reg for future use
 408         andb $0x0f,%ah          # mask processor family
 409         movb %ah,X86
 410         andb $0xf0,%al          # mask model
 411         shrb $4,%al
 412         movb %al,X86_MODEL
 413         andb $0x0f,%cl          # mask mask revision
 414         movb %cl,X86_MASK
 415         movl %edx,X86_CAPABILITY
 416
 417 is486:  movl $0x50022,%ecx      # set AM, WP, NE and MP
 418         jmp 2f
 419
 420 is386:  movl $2,%ecx            # set MP
 421 2:      movl %cr0,%eax
 422         andl $0x80000011,%eax   # Save PG,PE,ET
 423         orl %ecx,%eax
 424         movl %eax,%cr0
 425
 426         call check_x87
 427         lgdt early_gdt_descr
 428         lidt idt_descr
 429         ljmp $(__KERNEL_CS),$1f
 430 1:      movl $(__KERNEL_DS),%eax        # reload all the segment registers
 431         movl %eax,%ss                   # after changing gdt.
 432         movl %eax,%fs                   # gets reset once there's real percpu
 433
 434         movl $(__USER_DS),%eax          # DS/ES contains default USER segment
 435         movl %eax,%ds
 436         movl %eax,%es
 437
 438         xorl %eax,%eax                  # Clear GS and LDT
 439         movl %eax,%gs
 440         lldt %ax
 441
 442         cld                     # gcc2 wants the direction flag cleared at all times
 443         pushl $0                # fake return address for unwinder
 444 #ifdef CONFIG_SMP
 445         movb ready, %cl
 446         movb $1, ready
 447         cmpb $0,%cl             # the first CPU calls start_kernel
 448         je   1f
 449         movl $(__KERNEL_PERCPU), %eax
 450         movl %eax,%fs           # set this cpu's percpu
 451         movl (stack_start), %esp
 452 1:
 453 #endif /* CONFIG_SMP */
 454         jmp *(initial_code)
 455
 456 /*
 457  * We depend on ET to be correct. This checks for 287/387.
 458  */
 459 check_x87:
 460         movb $0,X86_HARD_MATH
 461         clts
 462         fninit
 463         fstsw %ax
 464         cmpb $0,%al
 465         je 1f
 466         movl %cr0,%eax          /* no coprocessor: have to set bits */
 467         xorl $4,%eax            /* set EM */
 468         movl %eax,%cr0
 469         ret
 470         ALIGN
 471 1:      movb $1,X86_HARD_MATH
 472         .byte 0xDB,0xE4         /* fsetpm for 287, ignored by 387 */
 473         ret
 474
 475 /*
 476  *  setup_idt
 477  *
 478  *  sets up a idt with 256 entries pointing to
 479  *  ignore_int, interrupt gates. It doesn't actually load
 480  *  idt - that can be done only after paging has been enabled
 481  *  and the kernel moved to PAGE_OFFSET. Interrupts
 482  *  are enabled elsewhere, when we can be relatively
 483  *  sure everything is ok.
 484  *
 485  *  Warning: %esi is live across this function.
 486  */
 487 setup_idt:
 488         lea ignore_int,%edx
 489         movl $(__KERNEL_CS << 16),%eax
 490         movw %dx,%ax            /* selector = 0x0010 = cs */
 491         movw $0x8E00,%dx        /* interrupt gate - dpl=0, present */
 492
 493         lea idt_table,%edi
 494         mov $256,%ecx
 495 rp_sidt:
 496         movl %eax,(%edi)
 497         movl %edx,4(%edi)
 498         addl $8,%edi
 499         dec %ecx
 500         jne rp_sidt
 501
 502 .macro  set_early_handler handler,trapno
 503         lea \handler,%edx
 504         movl $(__KERNEL_CS << 16),%eax
 505         movw %dx,%ax
 506         movw $0x8E00,%dx        /* interrupt gate - dpl=0, present */
 507         lea idt_table,%edi
 508         movl %eax,8*\trapno(%edi)
 509         movl %edx,8*\trapno+4(%edi)
 510 .endm
 511
 512         set_early_handler handler=early_divide_err,trapno=0
 513         set_early_handler handler=early_illegal_opcode,trapno=6
 514         set_early_handler handler=early_protection_fault,trapno=13
 515         set_early_handler handler=early_page_fault,trapno=14
 516
 517         ret
 518
 519 early_divide_err:
 520         xor %edx,%edx
 521         pushl $0        /* fake errcode */
 522         jmp early_fault
 523
 524 early_illegal_opcode:
 525         movl $6,%edx
 526         pushl $0        /* fake errcode */
 527         jmp early_fault
 528
 529 early_protection_fault:
 530         movl $13,%edx
 531         jmp early_fault
 532
 533 early_page_fault:
 534         movl $14,%edx
 535         jmp early_fault
 536
 537 early_fault:
 538         cld
 539 #ifdef CONFIG_PRINTK
 540         pusha
 541         movl $(__KERNEL_DS),%eax
 542         movl %eax,%ds
 543         movl %eax,%es
 544         cmpl $2,early_recursion_flag
 545         je hlt_loop
 546         incl early_recursion_flag
 547         movl %cr2,%eax
 548         pushl %eax
 549         pushl %edx              /* trapno */
 550         pushl $fault_msg
 551 #ifdef CONFIG_EARLY_PRINTK
 552         call early_printk
 553 #else
 554         call printk
 555 #endif
 556 #endif
 557         call dump_stack
 558 hlt_loop:
 559         hlt
 560         jmp hlt_loop
 561
 562 /* This is the default interrupt "handler" :-) */
 563         ALIGN
 564 ignore_int:
 565         cld
 566 #ifdef CONFIG_PRINTK
 567         pushl %eax
 568         pushl %ecx
 569         pushl %edx
 570         pushl %es
 571         pushl %ds
 572         movl $(__KERNEL_DS),%eax
 573         movl %eax,%ds
 574         movl %eax,%es
 575         cmpl $2,early_recursion_flag
 576         je hlt_loop
 577         incl early_recursion_flag
 578         pushl 16(%esp)
 579         pushl 24(%esp)
 580         pushl 32(%esp)
 581         pushl 40(%esp)
 582         pushl $int_msg
 583 #ifdef CONFIG_EARLY_PRINTK
 584         call early_printk
 585 #else
 586         call printk
 587 #endif
 588         addl $(5*4),%esp
 589         popl %ds
 590         popl %es
 591         popl %edx
 592         popl %ecx
 593         popl %eax
 594 #endif
 595         iret
 596
 597 .section .cpuinit.data,"wa"
 598 .align 4
 599 ENTRY(initial_code)
 600         .long i386_start_kernel
 601
 602 .section .text
 603 /*
 604  * Real beginning of normal "text" segment
 605  */
 606 ENTRY(stext)
 607 ENTRY(_stext)
 608
 609 /*
 610  * BSS section
 611  */
 612 .section ".bss.page_aligned","wa"
 613         .align PAGE_SIZE_asm
 614 #ifdef CONFIG_X86_PAE
 615 swapper_pg_pmd:
 616         .fill 1024*KPMDS,4,0
 617 #else
 618 ENTRY(swapper_pg_dir)
 619         .fill 1024,4,0
 620 #endif
 621 swapper_pg_fixmap:
 622         .fill 1024,4,0
 623 ENTRY(empty_zero_page)
 624         .fill 4096,1,0
 625 /*
 626  * This starts the data section.
 627  */
 628 #ifdef CONFIG_X86_PAE
 629 .section ".data.page_aligned","wa"
 630         /* Page-aligned for the benefit of paravirt? */
 631         .align PAGE_SIZE_asm
 632 ENTRY(swapper_pg_dir)
 633         .long   pa(swapper_pg_pmd+PGD_IDENT_ATTR),0     /* low identity map */
 634 # if KPMDS == 3
 635         .long   pa(swapper_pg_pmd+PGD_IDENT_ATTR),0
 636         .long   pa(swapper_pg_pmd+PGD_IDENT_ATTR+0x1000),0
 637         .long   pa(swapper_pg_pmd+PGD_IDENT_ATTR+0x2000),0
 638 # elif KPMDS == 2
 639         .long   0,0
 640         .long   pa(swapper_pg_pmd+PGD_IDENT_ATTR),0
 641         .long   pa(swapper_pg_pmd+PGD_IDENT_ATTR+0x1000),0
 642 # elif KPMDS == 1
 643         .long   0,0
 644         .long   0,0
 645         .long   pa(swapper_pg_pmd+PGD_IDENT_ATTR),0
 646 # else
 647 #  error "Kernel PMDs should be 1, 2 or 3"
 648 # endif
 649         .align PAGE_SIZE_asm            /* needs to be page-sized too */
 650 #endif
 651
 652 .data
 653 ENTRY(stack_start)
 654         .long init_thread_union+THREAD_SIZE
 655         .long __BOOT_DS
 656
 657 ready:  .byte 0
 658
 659 early_recursion_flag:
 660         .long 0
 661
 662 int_msg:
 663         .asciz "Unknown interrupt or fault at EIP %p %p %p\n"
 664
 665 fault_msg:
 666 /* fault info: */
 667         .ascii "BUG: Int %d: CR2 %p\n"
 668 /* pusha regs: */
 669         .ascii "     EDI %p  ESI %p  EBP %p  ESP %p\n"
 670         .ascii "     EBX %p  EDX %p  ECX %p  EAX %p\n"
 671 /* fault frame: */
 672         .ascii "     err %p  EIP %p   CS %p  flg %p\n"
 673         .ascii "Stack: %p %p %p %p %p %p %p %p\n"
 674         .ascii "       %p %p %p %p %p %p %p %p\n"
 675         .asciz "       %p %p %p %p %p %p %p %p\n"
 676
 677 #include "../../x86/xen/xen-head.S"
 678
 679 /*
 680  * The IDT and GDT 'descriptors' are a strange 48-bit object
 681  * only used by the lidt and lgdt instructions. They are not
 682  * like usual segment descriptors - they consist of a 16-bit
 683  * segment size, and 32-bit linear address value:
 684  */
 685
 686 .globl boot_gdt_descr
 687 .globl idt_descr
 688
 689         ALIGN
 690 # early boot GDT descriptor (must use 1:1 address mapping)
 691         .word 0                         # 32 bit align gdt_desc.address
 692 boot_gdt_descr:
 693         .word __BOOT_DS+7
 694         .long boot_gdt - __PAGE_OFFSET
 695
 696         .word 0                         # 32-bit align idt_desc.address
 697 idt_descr:
 698         .word IDT_ENTRIES*8-1           # idt contains 256 entries
 699         .long idt_table
 700
 701 # boot GDT descriptor (later on used by CPU#0):
 702         .word 0                         # 32 bit align gdt_desc.address
 703 ENTRY(early_gdt_descr)
 704         .word GDT_ENTRIES*8-1
 705         .long per_cpu__gdt_page         /* Overwritten for secondary CPUs */
 706
 707 /*
 708  * The boot_gdt must mirror the equivalent in setup.S and is
 709  * used only for booting.
 710  */
 711         .align L1_CACHE_BYTES
 712 ENTRY(boot_gdt)
 713         .fill GDT_ENTRY_BOOT_CS,8,0
 714         .quad 0x00cf9a000000ffff        /* kernel 4GB code at 0x00000000 */
 715         .quad 0x00cf92000000ffff        /* kernel 4GB data at 0x00000000 */