arch/i386/kernel/entry.S

   1 /*
   2  *  linux/arch/i386/entry.S
   3  *
   4  *  Copyright (C) 1991, 1992  Linus Torvalds
   5  */
   6
   7 /*
   8  * entry.S contains the system-call and fault low-level handling routines.
   9  * This also contains the timer-interrupt handler, as well as all interrupts
  10  * and faults that can result in a task-switch.
  11  *
  12  * NOTE: This code handles signal-recognition, which happens every time
  13  * after a timer-interrupt and after each system call.
  14  *
  15  * I changed all the .align's to 4 (16 byte alignment), as that's faster
  16  * on a 486.
  17  *
  18  * Stack layout in 'ret_from_system_call':
  19  *      ptrace needs to have all regs on the stack.
  20  *      if the order here is changed, it needs to be
  21  *      updated in fork.c:copy_process, signal.c:do_signal,
  22  *      ptrace.c and ptrace.h
  23  *
  24  *       0(%esp) - %ebx
  25  *       4(%esp) - %ecx
  26  *       8(%esp) - %edx
  27  *       C(%esp) - %esi
  28  *      10(%esp) - %edi
  29  *      14(%esp) - %ebp
  30  *      18(%esp) - %eax
  31  *      1C(%esp) - %ds
  32  *      20(%esp) - %es
  33  *      24(%esp) - %gs
  34  *      28(%esp) - orig_eax
  35  *      2C(%esp) - %eip
  36  *      30(%esp) - %cs
  37  *      34(%esp) - %eflags
  38  *      38(%esp) - %oldesp
  39  *      3C(%esp) - %oldss
  40  *
  41  * "current" is in register %ebx during any slow entries.
  42  */
  43
  44 #include <linux/linkage.h>
  45 #include <asm/thread_info.h>
  46 #include <asm/irqflags.h>
  47 #include <asm/errno.h>
  48 #include <asm/segment.h>
  49 #include <asm/smp.h>
  50 #include <asm/page.h>
  51 #include <asm/desc.h>
  52 #include <asm/percpu.h>
  53 #include <asm/dwarf2.h>
  54 #include "irq_vectors.h"
  55
  56 /*
  57  * We use macros for low-level operations which need to be overridden
  58  * for paravirtualization.  The following will never clobber any registers:
  59  *   INTERRUPT_RETURN (aka. "iret")
  60  *   GET_CR0_INTO_EAX (aka. "movl %cr0, %eax")
  61  *   ENABLE_INTERRUPTS_SYSEXIT (aka "sti; sysexit").
  62  *
  63  * For DISABLE_INTERRUPTS/ENABLE_INTERRUPTS (aka "cli"/"sti"), you must
  64  * specify what registers can be overwritten (CLBR_NONE, CLBR_EAX/EDX/ECX/ANY).
  65  * Allowing a register to be clobbered can shrink the paravirt replacement
  66  * enough to patch inline, increasing performance.
  67  */
  68
  69 #define nr_syscalls ((syscall_table_size)/4)
  70
  71 CF_MASK         = 0x00000001
  72 TF_MASK         = 0x00000100
  73 IF_MASK         = 0x00000200
  74 DF_MASK         = 0x00000400
  75 NT_MASK         = 0x00004000
  76 VM_MASK         = 0x00020000
  77
  78 #ifdef CONFIG_PREEMPT
  79 #define preempt_stop(clobbers)  DISABLE_INTERRUPTS(clobbers); TRACE_IRQS_OFF
  80 #else
  81 #define preempt_stop(clobbers)
  82 #define resume_kernel           restore_nocheck
  83 #endif
  84
  85 .macro TRACE_IRQS_IRET
  86 #ifdef CONFIG_TRACE_IRQFLAGS
  87         testl $IF_MASK,PT_EFLAGS(%esp)     # interrupts off?
  88         jz 1f
  89         TRACE_IRQS_ON
  90 1:
  91 #endif
  92 .endm
  93
  94 #ifdef CONFIG_VM86
  95 #define resume_userspace_sig    check_userspace
  96 #else
  97 #define resume_userspace_sig    resume_userspace
  98 #endif
  99
 100 #define SAVE_ALL \
 101         cld; \
 102         pushl %gs; \
 103         CFI_ADJUST_CFA_OFFSET 4;\
 104         /*CFI_REL_OFFSET gs, 0;*/\
 105         pushl %es; \
 106         CFI_ADJUST_CFA_OFFSET 4;\
 107         /*CFI_REL_OFFSET es, 0;*/\
 108         pushl %ds; \
 109         CFI_ADJUST_CFA_OFFSET 4;\
 110         /*CFI_REL_OFFSET ds, 0;*/\
 111         pushl %eax; \
 112         CFI_ADJUST_CFA_OFFSET 4;\
 113         CFI_REL_OFFSET eax, 0;\
 114         pushl %ebp; \
 115         CFI_ADJUST_CFA_OFFSET 4;\
 116         CFI_REL_OFFSET ebp, 0;\
 117         pushl %edi; \
 118         CFI_ADJUST_CFA_OFFSET 4;\
 119         CFI_REL_OFFSET edi, 0;\
 120         pushl %esi; \
 121         CFI_ADJUST_CFA_OFFSET 4;\
 122         CFI_REL_OFFSET esi, 0;\
 123         pushl %edx; \
 124         CFI_ADJUST_CFA_OFFSET 4;\
 125         CFI_REL_OFFSET edx, 0;\
 126         pushl %ecx; \
 127         CFI_ADJUST_CFA_OFFSET 4;\
 128         CFI_REL_OFFSET ecx, 0;\
 129         pushl %ebx; \
 130         CFI_ADJUST_CFA_OFFSET 4;\
 131         CFI_REL_OFFSET ebx, 0;\
 132         movl $(__USER_DS), %edx; \
 133         movl %edx, %ds; \
 134         movl %edx, %es; \
 135         movl $(__KERNEL_PDA), %edx; \
 136         movl %edx, %gs
 137
 138 #define RESTORE_INT_REGS \
 139         popl %ebx;      \
 140         CFI_ADJUST_CFA_OFFSET -4;\
 141         CFI_RESTORE ebx;\
 142         popl %ecx;      \
 143         CFI_ADJUST_CFA_OFFSET -4;\
 144         CFI_RESTORE ecx;\
 145         popl %edx;      \
 146         CFI_ADJUST_CFA_OFFSET -4;\
 147         CFI_RESTORE edx;\
 148         popl %esi;      \
 149         CFI_ADJUST_CFA_OFFSET -4;\
 150         CFI_RESTORE esi;\
 151         popl %edi;      \
 152         CFI_ADJUST_CFA_OFFSET -4;\
 153         CFI_RESTORE edi;\
 154         popl %ebp;      \
 155         CFI_ADJUST_CFA_OFFSET -4;\
 156         CFI_RESTORE ebp;\
 157         popl %eax;      \
 158         CFI_ADJUST_CFA_OFFSET -4;\
 159         CFI_RESTORE eax
 160
 161 #define RESTORE_REGS    \
 162         RESTORE_INT_REGS; \
 163 1:      popl %ds;       \
 164         CFI_ADJUST_CFA_OFFSET -4;\
 165         /*CFI_RESTORE ds;*/\
 166 2:      popl %es;       \
 167         CFI_ADJUST_CFA_OFFSET -4;\
 168         /*CFI_RESTORE es;*/\
 169 3:      popl %gs;       \
 170         CFI_ADJUST_CFA_OFFSET -4;\
 171         /*CFI_RESTORE gs;*/\
 172 .pushsection .fixup,"ax";       \
 173 4:      movl $0,(%esp); \
 174         jmp 1b;         \
 175 5:      movl $0,(%esp); \
 176         jmp 2b;         \
 177 6:      movl $0,(%esp); \
 178         jmp 3b;         \
 179 .section __ex_table,"a";\
 180         .align 4;       \
 181         .long 1b,4b;    \
 182         .long 2b,5b;    \
 183         .long 3b,6b;    \
 184 .popsection
 185
 186 #define RING0_INT_FRAME \
 187         CFI_STARTPROC simple;\
 188         CFI_SIGNAL_FRAME;\
 189         CFI_DEF_CFA esp, 3*4;\
 190         /*CFI_OFFSET cs, -2*4;*/\
 191         CFI_OFFSET eip, -3*4
 192
 193 #define RING0_EC_FRAME \
 194         CFI_STARTPROC simple;\
 195         CFI_SIGNAL_FRAME;\
 196         CFI_DEF_CFA esp, 4*4;\
 197         /*CFI_OFFSET cs, -2*4;*/\
 198         CFI_OFFSET eip, -3*4
 199
 200 #define RING0_PTREGS_FRAME \
 201         CFI_STARTPROC simple;\
 202         CFI_SIGNAL_FRAME;\
 203         CFI_DEF_CFA esp, PT_OLDESP-PT_EBX;\
 204         /*CFI_OFFSET cs, PT_CS-PT_OLDESP;*/\
 205         CFI_OFFSET eip, PT_EIP-PT_OLDESP;\
 206         /*CFI_OFFSET es, PT_ES-PT_OLDESP;*/\
 207         /*CFI_OFFSET ds, PT_DS-PT_OLDESP;*/\
 208         CFI_OFFSET eax, PT_EAX-PT_OLDESP;\
 209         CFI_OFFSET ebp, PT_EBP-PT_OLDESP;\
 210         CFI_OFFSET edi, PT_EDI-PT_OLDESP;\
 211         CFI_OFFSET esi, PT_ESI-PT_OLDESP;\
 212         CFI_OFFSET edx, PT_EDX-PT_OLDESP;\
 213         CFI_OFFSET ecx, PT_ECX-PT_OLDESP;\
 214         CFI_OFFSET ebx, PT_EBX-PT_OLDESP
 215
 216 ENTRY(ret_from_fork)
 217         CFI_STARTPROC
 218         pushl %eax
 219         CFI_ADJUST_CFA_OFFSET 4
 220         call schedule_tail
 221         GET_THREAD_INFO(%ebp)
 222         popl %eax
 223         CFI_ADJUST_CFA_OFFSET -4
 224         pushl $0x0202                   # Reset kernel eflags
 225         CFI_ADJUST_CFA_OFFSET 4
 226         popfl
 227         CFI_ADJUST_CFA_OFFSET -4
 228         jmp syscall_exit
 229         CFI_ENDPROC
 230
 231 /*
 232  * Return to user mode is not as complex as all this looks,
 233  * but we want the default path for a system call return to
 234  * go as quickly as possible which is why some of this is
 235  * less clear than it otherwise should be.
 236  */
 237
 238         # userspace resumption stub bypassing syscall exit tracing
 239         ALIGN
 240         RING0_PTREGS_FRAME
 241 ret_from_exception:
 242         preempt_stop(CLBR_ANY)
 243 ret_from_intr:
 244         GET_THREAD_INFO(%ebp)
 245 check_userspace:
 246         movl PT_EFLAGS(%esp), %eax      # mix EFLAGS and CS
 247         movb PT_CS(%esp), %al
 248         andl $(VM_MASK | SEGMENT_RPL_MASK), %eax
 249         cmpl $USER_RPL, %eax
 250         jb resume_kernel                # not returning to v8086 or userspace
 251
 252 ENTRY(resume_userspace)
 253         DISABLE_INTERRUPTS(CLBR_ANY)    # make sure we don't miss an interrupt
 254                                         # setting need_resched or sigpending
 255                                         # between sampling and the iret
 256         movl TI_flags(%ebp), %ecx
 257         andl $_TIF_WORK_MASK, %ecx      # is there any work to be done on
 258                                         # int/exception return?
 259         jne work_pending
 260         jmp restore_all
 261
 262 #ifdef CONFIG_PREEMPT
 263 ENTRY(resume_kernel)
 264         DISABLE_INTERRUPTS(CLBR_ANY)
 265         cmpl $0,TI_preempt_count(%ebp)  # non-zero preempt_count ?
 266         jnz restore_nocheck
 267 need_resched:
 268         movl TI_flags(%ebp), %ecx       # need_resched set ?
 269         testb $_TIF_NEED_RESCHED, %cl
 270         jz restore_all
 271         testl $IF_MASK,PT_EFLAGS(%esp)  # interrupts off (exception path) ?
 272         jz restore_all
 273         call preempt_schedule_irq
 274         jmp need_resched
 275 #endif
 276         CFI_ENDPROC
 277
 278 /* SYSENTER_RETURN points to after the "sysenter" instruction in
 279    the vsyscall page.  See vsyscall-sysentry.S, which defines the symbol.  */
 280
 281         # sysenter call handler stub
 282 ENTRY(sysenter_entry)
 283         CFI_STARTPROC simple
 284         CFI_SIGNAL_FRAME
 285         CFI_DEF_CFA esp, 0
 286         CFI_REGISTER esp, ebp
 287         movl TSS_sysenter_esp0(%esp),%esp
 288 sysenter_past_esp:
 289         /*
 290          * No need to follow this irqs on/off section: the syscall
 291          * disabled irqs and here we enable it straight after entry:
 292          */
 293         ENABLE_INTERRUPTS(CLBR_NONE)
 294         pushl $(__USER_DS)
 295         CFI_ADJUST_CFA_OFFSET 4
 296         /*CFI_REL_OFFSET ss, 0*/
 297         pushl %ebp
 298         CFI_ADJUST_CFA_OFFSET 4
 299         CFI_REL_OFFSET esp, 0
 300         pushfl
 301         CFI_ADJUST_CFA_OFFSET 4
 302         pushl $(__USER_CS)
 303         CFI_ADJUST_CFA_OFFSET 4
 304         /*CFI_REL_OFFSET cs, 0*/
 305         /*
 306          * Push current_thread_info()->sysenter_return to the stack.
 307          * A tiny bit of offset fixup is necessary - 4*4 means the 4 words
 308          * pushed above; +8 corresponds to copy_thread's esp0 setting.
 309          */
 310         pushl (TI_sysenter_return-THREAD_SIZE+8+4*4)(%esp)
 311         CFI_ADJUST_CFA_OFFSET 4
 312         CFI_REL_OFFSET eip, 0
 313
 314 /*
 315  * Load the potential sixth argument from user stack.
 316  * Careful about security.
 317  */
 318         cmpl $__PAGE_OFFSET-3,%ebp
 319         jae syscall_fault
 320 1:      movl (%ebp),%ebp
 321 .section __ex_table,"a"
 322         .align 4
 323         .long 1b,syscall_fault
 324 .previous
 325
 326         pushl %eax
 327         CFI_ADJUST_CFA_OFFSET 4
 328         SAVE_ALL
 329         GET_THREAD_INFO(%ebp)
 330
 331         /* Note, _TIF_SECCOMP is bit number 8, and so it needs testw and not testb */
 332         testw $(_TIF_SYSCALL_EMU|_TIF_SYSCALL_TRACE|_TIF_SECCOMP|_TIF_SYSCALL_AUDIT),TI_flags(%ebp)
 333         jnz syscall_trace_entry
 334         cmpl $(nr_syscalls), %eax
 335         jae syscall_badsys
 336         call *sys_call_table(,%eax,4)
 337         movl %eax,PT_EAX(%esp)
 338         DISABLE_INTERRUPTS(CLBR_ECX|CLBR_EDX)
 339         TRACE_IRQS_OFF
 340         movl TI_flags(%ebp), %ecx
 341         testw $_TIF_ALLWORK_MASK, %cx
 342         jne syscall_exit_work
 343 /* if something modifies registers it must also disable sysexit */
 344         movl PT_EIP(%esp), %edx
 345         movl PT_OLDESP(%esp), %ecx
 346         xorl %ebp,%ebp
 347         TRACE_IRQS_ON
 348 1:      mov  PT_GS(%esp), %gs
 349         ENABLE_INTERRUPTS_SYSEXIT
 350         CFI_ENDPROC
 351 .pushsection .fixup,"ax"
 352 2:      movl $0,PT_GS(%esp)
 353         jmp 1b
 354 .section __ex_table,"a"
 355         .align 4
 356         .long 1b,2b
 357 .popsection
 358
 359         # system call handler stub
 360 ENTRY(system_call)
 361         RING0_INT_FRAME                 # can't unwind into user space anyway
 362         pushl %eax                      # save orig_eax
 363         CFI_ADJUST_CFA_OFFSET 4
 364         SAVE_ALL
 365         GET_THREAD_INFO(%ebp)
 366         testl $TF_MASK,PT_EFLAGS(%esp)
 367         jz no_singlestep
 368         orl $_TIF_SINGLESTEP,TI_flags(%ebp)
 369 no_singlestep:
 370                                         # system call tracing in operation / emulation
 371         /* Note, _TIF_SECCOMP is bit number 8, and so it needs testw and not testb */
 372         testw $(_TIF_SYSCALL_EMU|_TIF_SYSCALL_TRACE|_TIF_SECCOMP|_TIF_SYSCALL_AUDIT),TI_flags(%ebp)
 373         jnz syscall_trace_entry
 374         cmpl $(nr_syscalls), %eax
 375         jae syscall_badsys
 376 syscall_call:
 377         call *sys_call_table(,%eax,4)
 378         movl %eax,PT_EAX(%esp)          # store the return value
 379 syscall_exit:
 380         DISABLE_INTERRUPTS(CLBR_ANY)    # make sure we don't miss an interrupt
 381                                         # setting need_resched or sigpending
 382                                         # between sampling and the iret
 383         TRACE_IRQS_OFF
 384         movl TI_flags(%ebp), %ecx
 385         testw $_TIF_ALLWORK_MASK, %cx   # current->work
 386         jne syscall_exit_work
 387
 388 restore_all:
 389         movl PT_EFLAGS(%esp), %eax      # mix EFLAGS, SS and CS
 390         # Warning: PT_OLDSS(%esp) contains the wrong/random values if we
 391         # are returning to the kernel.
 392         # See comments in process.c:copy_thread() for details.
 393         movb PT_OLDSS(%esp), %ah
 394         movb PT_CS(%esp), %al
 395         andl $(VM_MASK | (SEGMENT_TI_MASK << 8) | SEGMENT_RPL_MASK), %eax
 396         cmpl $((SEGMENT_LDT << 8) | USER_RPL), %eax
 397         CFI_REMEMBER_STATE
 398         je ldt_ss                       # returning to user-space with LDT SS
 399 restore_nocheck:
 400         TRACE_IRQS_IRET
 401 restore_nocheck_notrace:
 402         RESTORE_REGS
 403         addl $4, %esp                   # skip orig_eax/error_code
 404         CFI_ADJUST_CFA_OFFSET -4
 405 1:      INTERRUPT_RETURN
 406 .section .fixup,"ax"
 407 iret_exc:
 408         TRACE_IRQS_ON
 409         ENABLE_INTERRUPTS(CLBR_NONE)
 410         pushl $0                        # no error code
 411         pushl $do_iret_error
 412         jmp error_code
 413 .previous
 414 .section __ex_table,"a"
 415         .align 4
 416         .long 1b,iret_exc
 417 .previous
 418
 419         CFI_RESTORE_STATE
 420 ldt_ss:
 421         larl PT_OLDSS(%esp), %eax
 422         jnz restore_nocheck
 423         testl $0x00400000, %eax         # returning to 32bit stack?
 424         jnz restore_nocheck             # allright, normal return
 425
 426 #ifdef CONFIG_PARAVIRT
 427         /*
 428          * The kernel can't run on a non-flat stack if paravirt mode
 429          * is active.  Rather than try to fixup the high bits of
 430          * ESP, bypass this code entirely.  This may break DOSemu
 431          * and/or Wine support in a paravirt VM, although the option
 432          * is still available to implement the setting of the high
 433          * 16-bits in the INTERRUPT_RETURN paravirt-op.
 434          */
 435         cmpl $0, paravirt_ops+PARAVIRT_enabled
 436         jne restore_nocheck
 437 #endif
 438
 439         /* If returning to userspace with 16bit stack,
 440          * try to fix the higher word of ESP, as the CPU
 441          * won't restore it.
 442          * This is an "official" bug of all the x86-compatible
 443          * CPUs, which we can try to work around to make
 444          * dosemu and wine happy. */
 445         movl PT_OLDESP(%esp), %eax
 446         movl %esp, %edx
 447         call patch_espfix_desc
 448         pushl $__ESPFIX_SS
 449         CFI_ADJUST_CFA_OFFSET 4
 450         pushl %eax
 451         CFI_ADJUST_CFA_OFFSET 4
 452         DISABLE_INTERRUPTS(CLBR_EAX)
 453         TRACE_IRQS_OFF
 454         lss (%esp), %esp
 455         CFI_ADJUST_CFA_OFFSET -8
 456         jmp restore_nocheck
 457         CFI_ENDPROC
 458
 459         # perform work that needs to be done immediately before resumption
 460         ALIGN
 461         RING0_PTREGS_FRAME              # can't unwind into user space anyway
 462 work_pending:
 463         testb $_TIF_NEED_RESCHED, %cl
 464         jz work_notifysig
 465 work_resched:
 466         call schedule
 467         DISABLE_INTERRUPTS(CLBR_ANY)    # make sure we don't miss an interrupt
 468                                         # setting need_resched or sigpending
 469                                         # between sampling and the iret
 470         TRACE_IRQS_OFF
 471         movl TI_flags(%ebp), %ecx
 472         andl $_TIF_WORK_MASK, %ecx      # is there any work to be done other
 473                                         # than syscall tracing?
 474         jz restore_all
 475         testb $_TIF_NEED_RESCHED, %cl
 476         jnz work_resched
 477
 478 work_notifysig:                         # deal with pending signals and
 479                                         # notify-resume requests
 480 #ifdef CONFIG_VM86
 481         testl $VM_MASK, PT_EFLAGS(%esp)
 482         movl %esp, %eax
 483         jne work_notifysig_v86          # returning to kernel-space or
 484                                         # vm86-space
 485         xorl %edx, %edx
 486         call do_notify_resume
 487         jmp resume_userspace_sig
 488
 489         ALIGN
 490 work_notifysig_v86:
 491         pushl %ecx                      # save ti_flags for do_notify_resume
 492         CFI_ADJUST_CFA_OFFSET 4
 493         call save_v86_state             # %eax contains pt_regs pointer
 494         popl %ecx
 495         CFI_ADJUST_CFA_OFFSET -4
 496         movl %eax, %esp
 497 #else
 498         movl %esp, %eax
 499 #endif
 500         xorl %edx, %edx
 501         call do_notify_resume
 502         jmp resume_userspace_sig
 503
 504         # perform syscall exit tracing
 505         ALIGN
 506 syscall_trace_entry:
 507         movl $-ENOSYS,PT_EAX(%esp)
 508         movl %esp, %eax
 509         xorl %edx,%edx
 510         call do_syscall_trace
 511         cmpl $0, %eax
 512         jne resume_userspace            # ret != 0 -> running under PTRACE_SYSEMU,
 513                                         # so must skip actual syscall
 514         movl PT_ORIG_EAX(%esp), %eax
 515         cmpl $(nr_syscalls), %eax
 516         jnae syscall_call
 517         jmp syscall_exit
 518
 519         # perform syscall exit tracing
 520         ALIGN
 521 syscall_exit_work:
 522         testb $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP), %cl
 523         jz work_pending
 524         TRACE_IRQS_ON
 525         ENABLE_INTERRUPTS(CLBR_ANY)     # could let do_syscall_trace() call
 526                                         # schedule() instead
 527         movl %esp, %eax
 528         movl $1, %edx
 529         call do_syscall_trace
 530         jmp resume_userspace
 531         CFI_ENDPROC
 532
 533         RING0_INT_FRAME                 # can't unwind into user space anyway
 534 syscall_fault:
 535         pushl %eax                      # save orig_eax
 536         CFI_ADJUST_CFA_OFFSET 4
 537         SAVE_ALL
 538         GET_THREAD_INFO(%ebp)
 539         movl $-EFAULT,PT_EAX(%esp)
 540         jmp resume_userspace
 541
 542 syscall_badsys:
 543         movl $-ENOSYS,PT_EAX(%esp)
 544         jmp resume_userspace
 545         CFI_ENDPROC
 546
 547 #define FIXUP_ESPFIX_STACK \
 548         /* since we are on a wrong stack, we cant make it a C code :( */ \
 549         movl %gs:PDA_cpu, %ebx; \
 550         PER_CPU(cpu_gdt_descr, %ebx); \
 551         movl GDS_address(%ebx), %ebx; \
 552         GET_DESC_BASE(GDT_ENTRY_ESPFIX_SS, %ebx, %eax, %ax, %al, %ah); \
 553         addl %esp, %eax; \
 554         pushl $__KERNEL_DS; \
 555         CFI_ADJUST_CFA_OFFSET 4; \
 556         pushl %eax; \
 557         CFI_ADJUST_CFA_OFFSET 4; \
 558         lss (%esp), %esp; \
 559         CFI_ADJUST_CFA_OFFSET -8;
 560 #define UNWIND_ESPFIX_STACK \
 561         movl %ss, %eax; \
 562         /* see if on espfix stack */ \
 563         cmpw $__ESPFIX_SS, %ax; \
 564         jne 27f; \
 565         movl $__KERNEL_DS, %eax; \
 566         movl %eax, %ds; \
 567         movl %eax, %es; \
 568         /* switch to normal stack */ \
 569         FIXUP_ESPFIX_STACK; \
 570 27:;
 571
 572 /*
 573  * Build the entry stubs and pointer table with
 574  * some assembler magic.
 575  */
 576 .data
 577 ENTRY(interrupt)
 578 .text
 579
 580 vector=0
 581 ENTRY(irq_entries_start)
 582         RING0_INT_FRAME
 583 .rept NR_IRQS
 584         ALIGN
 585  .if vector
 586         CFI_ADJUST_CFA_OFFSET -4
 587  .endif
 588 1:      pushl $~(vector)
 589         CFI_ADJUST_CFA_OFFSET 4
 590         jmp common_interrupt
 591 .data
 592         .long 1b
 593 .text
 594 vector=vector+1
 595 .endr
 596
 597 /*
 598  * the CPU automatically disables interrupts when executing an IRQ vector,
 599  * so IRQ-flags tracing has to follow that:
 600  */
 601         ALIGN
 602 common_interrupt:
 603         SAVE_ALL
 604         TRACE_IRQS_OFF
 605         movl %esp,%eax
 606         call do_IRQ
 607         jmp ret_from_intr
 608         CFI_ENDPROC
 609
 610 #define BUILD_INTERRUPT(name, nr)       \
 611 ENTRY(name)                             \
 612         RING0_INT_FRAME;                \
 613         pushl $~(nr);                   \
 614         CFI_ADJUST_CFA_OFFSET 4;        \
 615         SAVE_ALL;                       \
 616         TRACE_IRQS_OFF                  \
 617         movl %esp,%eax;                 \
 618         call smp_/**/name;              \
 619         jmp ret_from_intr;              \
 620         CFI_ENDPROC
 621
 622 /* The include is where all of the SMP etc. interrupts come from */
 623 #include "entry_arch.h"
 624
 625 KPROBE_ENTRY(page_fault)
 626         RING0_EC_FRAME
 627         pushl $do_page_fault
 628         CFI_ADJUST_CFA_OFFSET 4
 629         ALIGN
 630 error_code:
 631         /* the function address is in %gs's slot on the stack */
 632         pushl %es
 633         CFI_ADJUST_CFA_OFFSET 4
 634         /*CFI_REL_OFFSET es, 0*/
 635         pushl %ds
 636         CFI_ADJUST_CFA_OFFSET 4
 637         /*CFI_REL_OFFSET ds, 0*/
 638         pushl %eax
 639         CFI_ADJUST_CFA_OFFSET 4
 640         CFI_REL_OFFSET eax, 0
 641         pushl %ebp
 642         CFI_ADJUST_CFA_OFFSET 4
 643         CFI_REL_OFFSET ebp, 0
 644         pushl %edi
 645         CFI_ADJUST_CFA_OFFSET 4
 646         CFI_REL_OFFSET edi, 0
 647         pushl %esi
 648         CFI_ADJUST_CFA_OFFSET 4
 649         CFI_REL_OFFSET esi, 0
 650         pushl %edx
 651         CFI_ADJUST_CFA_OFFSET 4
 652         CFI_REL_OFFSET edx, 0
 653         pushl %ecx
 654         CFI_ADJUST_CFA_OFFSET 4
 655         CFI_REL_OFFSET ecx, 0
 656         pushl %ebx
 657         CFI_ADJUST_CFA_OFFSET 4
 658         CFI_REL_OFFSET ebx, 0
 659         cld
 660         pushl %gs
 661         CFI_ADJUST_CFA_OFFSET 4
 662         /*CFI_REL_OFFSET gs, 0*/
 663         movl $(__KERNEL_PDA), %ecx
 664         movl %ecx, %gs
 665         UNWIND_ESPFIX_STACK
 666         popl %ecx
 667         CFI_ADJUST_CFA_OFFSET -4
 668         /*CFI_REGISTER es, ecx*/
 669         movl PT_GS(%esp), %edi          # get the function address
 670         movl PT_ORIG_EAX(%esp), %edx    # get the error code
 671         movl $-1, PT_ORIG_EAX(%esp)     # no syscall to restart
 672         mov  %ecx, PT_GS(%esp)
 673         /*CFI_REL_OFFSET gs, ES*/
 674         movl $(__USER_DS), %ecx
 675         movl %ecx, %ds
 676         movl %ecx, %es
 677         movl %esp,%eax                  # pt_regs pointer
 678         call *%edi
 679         jmp ret_from_exception
 680         CFI_ENDPROC
 681 KPROBE_END(page_fault)
 682
 683 ENTRY(coprocessor_error)
 684         RING0_INT_FRAME
 685         pushl $0
 686         CFI_ADJUST_CFA_OFFSET 4
 687         pushl $do_coprocessor_error
 688         CFI_ADJUST_CFA_OFFSET 4
 689         jmp error_code
 690         CFI_ENDPROC
 691
 692 ENTRY(simd_coprocessor_error)
 693         RING0_INT_FRAME
 694         pushl $0
 695         CFI_ADJUST_CFA_OFFSET 4
 696         pushl $do_simd_coprocessor_error
 697         CFI_ADJUST_CFA_OFFSET 4
 698         jmp error_code
 699         CFI_ENDPROC
 700
 701 ENTRY(device_not_available)
 702         RING0_INT_FRAME
 703         pushl $-1                       # mark this as an int
 704         CFI_ADJUST_CFA_OFFSET 4
 705         SAVE_ALL
 706         GET_CR0_INTO_EAX
 707         testl $0x4, %eax                # EM (math emulation bit)
 708         jne device_not_available_emulate
 709         preempt_stop(CLBR_ANY)
 710         call math_state_restore
 711         jmp ret_from_exception
 712 device_not_available_emulate:
 713         pushl $0                        # temporary storage for ORIG_EIP
 714         CFI_ADJUST_CFA_OFFSET 4
 715         call math_emulate
 716         addl $4, %esp
 717         CFI_ADJUST_CFA_OFFSET -4
 718         jmp ret_from_exception
 719         CFI_ENDPROC
 720
 721 /*
 722  * Debug traps and NMI can happen at the one SYSENTER instruction
 723  * that sets up the real kernel stack. Check here, since we can't
 724  * allow the wrong stack to be used.
 725  *
 726  * "TSS_sysenter_esp0+12" is because the NMI/debug handler will have
 727  * already pushed 3 words if it hits on the sysenter instruction:
 728  * eflags, cs and eip.
 729  *
 730  * We just load the right stack, and push the three (known) values
 731  * by hand onto the new stack - while updating the return eip past
 732  * the instruction that would have done it for sysenter.
 733  */
 734 #define FIX_STACK(offset, ok, label)            \
 735         cmpw $__KERNEL_CS,4(%esp);              \
 736         jne ok;                                 \
 737 label:                                          \
 738         movl TSS_sysenter_esp0+offset(%esp),%esp;       \
 739         CFI_DEF_CFA esp, 0;                     \
 740         CFI_UNDEFINED eip;                      \
 741         pushfl;                                 \
 742         CFI_ADJUST_CFA_OFFSET 4;                \
 743         pushl $__KERNEL_CS;                     \
 744         CFI_ADJUST_CFA_OFFSET 4;                \
 745         pushl $sysenter_past_esp;               \
 746         CFI_ADJUST_CFA_OFFSET 4;                \
 747         CFI_REL_OFFSET eip, 0
 748
 749 KPROBE_ENTRY(debug)
 750         RING0_INT_FRAME
 751         cmpl $sysenter_entry,(%esp)
 752         jne debug_stack_correct
 753         FIX_STACK(12, debug_stack_correct, debug_esp_fix_insn)
 754 debug_stack_correct:
 755         pushl $-1                       # mark this as an int
 756         CFI_ADJUST_CFA_OFFSET 4
 757         SAVE_ALL
 758         xorl %edx,%edx                  # error code 0
 759         movl %esp,%eax                  # pt_regs pointer
 760         call do_debug
 761         jmp ret_from_exception
 762         CFI_ENDPROC
 763 KPROBE_END(debug)
 764
 765 /*
 766  * NMI is doubly nasty. It can happen _while_ we're handling
 767  * a debug fault, and the debug fault hasn't yet been able to
 768  * clear up the stack. So we first check whether we got  an
 769  * NMI on the sysenter entry path, but after that we need to
 770  * check whether we got an NMI on the debug path where the debug
 771  * fault happened on the sysenter path.
 772  */
 773 KPROBE_ENTRY(nmi)
 774         RING0_INT_FRAME
 775         pushl %eax
 776         CFI_ADJUST_CFA_OFFSET 4
 777         movl %ss, %eax
 778         cmpw $__ESPFIX_SS, %ax
 779         popl %eax
 780         CFI_ADJUST_CFA_OFFSET -4
 781         je nmi_espfix_stack
 782         cmpl $sysenter_entry,(%esp)
 783         je nmi_stack_fixup
 784         pushl %eax
 785         CFI_ADJUST_CFA_OFFSET 4
 786         movl %esp,%eax
 787         /* Do not access memory above the end of our stack page,
 788          * it might not exist.
 789          */
 790         andl $(THREAD_SIZE-1),%eax
 791         cmpl $(THREAD_SIZE-20),%eax
 792         popl %eax
 793         CFI_ADJUST_CFA_OFFSET -4
 794         jae nmi_stack_correct
 795         cmpl $sysenter_entry,12(%esp)
 796         je nmi_debug_stack_check
 797 nmi_stack_correct:
 798         /* We have a RING0_INT_FRAME here */
 799         pushl %eax
 800         CFI_ADJUST_CFA_OFFSET 4
 801         SAVE_ALL
 802         xorl %edx,%edx          # zero error code
 803         movl %esp,%eax          # pt_regs pointer
 804         call do_nmi
 805         jmp restore_nocheck_notrace
 806         CFI_ENDPROC
 807
 808 nmi_stack_fixup:
 809         RING0_INT_FRAME
 810         FIX_STACK(12,nmi_stack_correct, 1)
 811         jmp nmi_stack_correct
 812
 813 nmi_debug_stack_check:
 814         /* We have a RING0_INT_FRAME here */
 815         cmpw $__KERNEL_CS,16(%esp)
 816         jne nmi_stack_correct
 817         cmpl $debug,(%esp)
 818         jb nmi_stack_correct
 819         cmpl $debug_esp_fix_insn,(%esp)
 820         ja nmi_stack_correct
 821         FIX_STACK(24,nmi_stack_correct, 1)
 822         jmp nmi_stack_correct
 823
 824 nmi_espfix_stack:
 825         /* We have a RING0_INT_FRAME here.
 826          *
 827          * create the pointer to lss back
 828          */
 829         pushl %ss
 830         CFI_ADJUST_CFA_OFFSET 4
 831         pushl %esp
 832         CFI_ADJUST_CFA_OFFSET 4
 833         addw $4, (%esp)
 834         /* copy the iret frame of 12 bytes */
 835         .rept 3
 836         pushl 16(%esp)
 837         CFI_ADJUST_CFA_OFFSET 4
 838         .endr
 839         pushl %eax
 840         CFI_ADJUST_CFA_OFFSET 4
 841         SAVE_ALL
 842         FIXUP_ESPFIX_STACK              # %eax == %esp
 843         xorl %edx,%edx                  # zero error code
 844         call do_nmi
 845         RESTORE_REGS
 846         lss 12+4(%esp), %esp            # back to espfix stack
 847         CFI_ADJUST_CFA_OFFSET -24
 848 1:      INTERRUPT_RETURN
 849         CFI_ENDPROC
 850 .section __ex_table,"a"
 851         .align 4
 852         .long 1b,iret_exc
 853 .previous
 854 KPROBE_END(nmi)
 855
 856 #ifdef CONFIG_PARAVIRT
 857 ENTRY(native_iret)
 858 1:      iret
 859 .section __ex_table,"a"
 860         .align 4
 861         .long 1b,iret_exc
 862 .previous
 863
 864 ENTRY(native_irq_enable_sysexit)
 865         sti
 866         sysexit
 867 #endif
 868
 869 KPROBE_ENTRY(int3)
 870         RING0_INT_FRAME
 871         pushl $-1                       # mark this as an int
 872         CFI_ADJUST_CFA_OFFSET 4
 873         SAVE_ALL
 874         xorl %edx,%edx          # zero error code
 875         movl %esp,%eax          # pt_regs pointer
 876         call do_int3
 877         jmp ret_from_exception
 878         CFI_ENDPROC
 879 KPROBE_END(int3)
 880
 881 ENTRY(overflow)
 882         RING0_INT_FRAME
 883         pushl $0
 884         CFI_ADJUST_CFA_OFFSET 4
 885         pushl $do_overflow
 886         CFI_ADJUST_CFA_OFFSET 4
 887         jmp error_code
 888         CFI_ENDPROC
 889
 890 ENTRY(bounds)
 891         RING0_INT_FRAME
 892         pushl $0
 893         CFI_ADJUST_CFA_OFFSET 4
 894         pushl $do_bounds
 895         CFI_ADJUST_CFA_OFFSET 4
 896         jmp error_code
 897         CFI_ENDPROC
 898
 899 ENTRY(invalid_op)
 900         RING0_INT_FRAME
 901         pushl $0
 902         CFI_ADJUST_CFA_OFFSET 4
 903         pushl $do_invalid_op
 904         CFI_ADJUST_CFA_OFFSET 4
 905         jmp error_code
 906         CFI_ENDPROC
 907
 908 ENTRY(coprocessor_segment_overrun)
 909         RING0_INT_FRAME
 910         pushl $0
 911         CFI_ADJUST_CFA_OFFSET 4
 912         pushl $do_coprocessor_segment_overrun
 913         CFI_ADJUST_CFA_OFFSET 4
 914         jmp error_code
 915         CFI_ENDPROC
 916
 917 ENTRY(invalid_TSS)
 918         RING0_EC_FRAME
 919         pushl $do_invalid_TSS
 920         CFI_ADJUST_CFA_OFFSET 4
 921         jmp error_code
 922         CFI_ENDPROC
 923
 924 ENTRY(segment_not_present)
 925         RING0_EC_FRAME
 926         pushl $do_segment_not_present
 927         CFI_ADJUST_CFA_OFFSET 4
 928         jmp error_code
 929         CFI_ENDPROC
 930
 931 ENTRY(stack_segment)
 932         RING0_EC_FRAME
 933         pushl $do_stack_segment
 934         CFI_ADJUST_CFA_OFFSET 4
 935         jmp error_code
 936         CFI_ENDPROC
 937
 938 KPROBE_ENTRY(general_protection)
 939         RING0_EC_FRAME
 940         pushl $do_general_protection
 941         CFI_ADJUST_CFA_OFFSET 4
 942         jmp error_code
 943         CFI_ENDPROC
 944 KPROBE_END(general_protection)
 945
 946 ENTRY(alignment_check)
 947         RING0_EC_FRAME
 948         pushl $do_alignment_check
 949         CFI_ADJUST_CFA_OFFSET 4
 950         jmp error_code
 951         CFI_ENDPROC
 952
 953 ENTRY(divide_error)
 954         RING0_INT_FRAME
 955         pushl $0                        # no error code
 956         CFI_ADJUST_CFA_OFFSET 4
 957         pushl $do_divide_error
 958         CFI_ADJUST_CFA_OFFSET 4
 959         jmp error_code
 960         CFI_ENDPROC
 961
 962 #ifdef CONFIG_X86_MCE
 963 ENTRY(machine_check)
 964         RING0_INT_FRAME
 965         pushl $0
 966         CFI_ADJUST_CFA_OFFSET 4
 967         pushl machine_check_vector
 968         CFI_ADJUST_CFA_OFFSET 4
 969         jmp error_code
 970         CFI_ENDPROC
 971 #endif
 972
 973 ENTRY(spurious_interrupt_bug)
 974         RING0_INT_FRAME
 975         pushl $0
 976         CFI_ADJUST_CFA_OFFSET 4
 977         pushl $do_spurious_interrupt_bug
 978         CFI_ADJUST_CFA_OFFSET 4
 979         jmp error_code
 980         CFI_ENDPROC
 981
 982 #ifdef CONFIG_STACK_UNWIND
 983 ENTRY(arch_unwind_init_running)
 984         CFI_STARTPROC
 985         movl    4(%esp), %edx
 986         movl    (%esp), %ecx
 987         leal    4(%esp), %eax
 988         movl    %ebx, PT_EBX(%edx)
 989         xorl    %ebx, %ebx
 990         movl    %ebx, PT_ECX(%edx)
 991         movl    %ebx, PT_EDX(%edx)
 992         movl    %esi, PT_ESI(%edx)
 993         movl    %edi, PT_EDI(%edx)
 994         movl    %ebp, PT_EBP(%edx)
 995         movl    %ebx, PT_EAX(%edx)
 996         movl    $__USER_DS, PT_DS(%edx)
 997         movl    $__USER_DS, PT_ES(%edx)
 998         movl    $0, PT_GS(%edx)
 999         movl    %ebx, PT_ORIG_EAX(%edx)
1000         movl    %ecx, PT_EIP(%edx)
1001         movl    12(%esp), %ecx
1002         movl    $__KERNEL_CS, PT_CS(%edx)
1003         movl    %ebx, PT_EFLAGS(%edx)
1004         movl    %eax, PT_OLDESP(%edx)
1005         movl    8(%esp), %eax
1006         movl    %ecx, 8(%esp)
1007         movl    PT_EBX(%edx), %ebx
1008         movl    $__KERNEL_DS, PT_OLDSS(%edx)
1009         jmpl    *%eax
1010         CFI_ENDPROC
1011 ENDPROC(arch_unwind_init_running)
1012 #endif
1013
1014 ENTRY(kernel_thread_helper)
1015         pushl $0                # fake return address for unwinder
1016         CFI_STARTPROC
1017         movl %edx,%eax
1018         push %edx
1019         CFI_ADJUST_CFA_OFFSET 4
1020         call *%ebx
1021         push %eax
1022         CFI_ADJUST_CFA_OFFSET 4
1023         call do_exit
1024         CFI_ENDPROC
1025 ENDPROC(kernel_thread_helper)
1026
1027 .section .rodata,"a"
1028 #include "syscall_table.S"
1029
1030 syscall_table_size=(.-sys_call_table)