arch/x86/kernel/entry_32.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 'syscall_exit':
  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) - %fs
  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 %fs; \
 103         CFI_ADJUST_CFA_OFFSET 4;\
 104         /*CFI_REL_OFFSET fs, 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_PERCPU), %edx; \
 136         movl %edx, %fs
 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 %fs;       \
 170         CFI_ADJUST_CFA_OFFSET -4;\
 171         /*CFI_RESTORE fs;*/\
 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 END(ret_from_fork)
 231
 232 /*
 233  * Return to user mode is not as complex as all this looks,
 234  * but we want the default path for a system call return to
 235  * go as quickly as possible which is why some of this is
 236  * less clear than it otherwise should be.
 237  */
 238
 239         # userspace resumption stub bypassing syscall exit tracing
 240         ALIGN
 241         RING0_PTREGS_FRAME
 242 ret_from_exception:
 243         preempt_stop(CLBR_ANY)
 244 ret_from_intr:
 245         GET_THREAD_INFO(%ebp)
 246 check_userspace:
 247         movl PT_EFLAGS(%esp), %eax      # mix EFLAGS and CS
 248         movb PT_CS(%esp), %al
 249         andl $(VM_MASK | SEGMENT_RPL_MASK), %eax
 250         cmpl $USER_RPL, %eax
 251         jb resume_kernel                # not returning to v8086 or userspace
 252
 253 ENTRY(resume_userspace)
 254         LOCKDEP_SYS_EXIT
 255         DISABLE_INTERRUPTS(CLBR_ANY)    # make sure we don't miss an interrupt
 256                                         # setting need_resched or sigpending
 257                                         # between sampling and the iret
 258         movl TI_flags(%ebp), %ecx
 259         andl $_TIF_WORK_MASK, %ecx      # is there any work to be done on
 260                                         # int/exception return?
 261         jne work_pending
 262         jmp restore_all
 263 END(ret_from_exception)
 264
 265 #ifdef CONFIG_PREEMPT
 266 ENTRY(resume_kernel)
 267         DISABLE_INTERRUPTS(CLBR_ANY)
 268         cmpl $0,TI_preempt_count(%ebp)  # non-zero preempt_count ?
 269         jnz restore_nocheck
 270 need_resched:
 271         movl TI_flags(%ebp), %ecx       # need_resched set ?
 272         testb $_TIF_NEED_RESCHED, %cl
 273         jz restore_all
 274         testl $IF_MASK,PT_EFLAGS(%esp)  # interrupts off (exception path) ?
 275         jz restore_all
 276         call preempt_schedule_irq
 277         jmp need_resched
 278 END(resume_kernel)
 279 #endif
 280         CFI_ENDPROC
 281
 282 /* SYSENTER_RETURN points to after the "sysenter" instruction in
 283    the vsyscall page.  See vsyscall-sysentry.S, which defines the symbol.  */
 284
 285         # sysenter call handler stub
 286 ENTRY(sysenter_entry)
 287         CFI_STARTPROC simple
 288         CFI_SIGNAL_FRAME
 289         CFI_DEF_CFA esp, 0
 290         CFI_REGISTER esp, ebp
 291         movl TSS_sysenter_esp0(%esp),%esp
 292 sysenter_past_esp:
 293         /*
 294          * No need to follow this irqs on/off section: the syscall
 295          * disabled irqs and here we enable it straight after entry:
 296          */
 297         ENABLE_INTERRUPTS(CLBR_NONE)
 298         pushl $(__USER_DS)
 299         CFI_ADJUST_CFA_OFFSET 4
 300         /*CFI_REL_OFFSET ss, 0*/
 301         pushl %ebp
 302         CFI_ADJUST_CFA_OFFSET 4
 303         CFI_REL_OFFSET esp, 0
 304         pushfl
 305         CFI_ADJUST_CFA_OFFSET 4
 306         pushl $(__USER_CS)
 307         CFI_ADJUST_CFA_OFFSET 4
 308         /*CFI_REL_OFFSET cs, 0*/
 309         /*
 310          * Push current_thread_info()->sysenter_return to the stack.
 311          * A tiny bit of offset fixup is necessary - 4*4 means the 4 words
 312          * pushed above; +8 corresponds to copy_thread's esp0 setting.
 313          */
 314         pushl (TI_sysenter_return-THREAD_SIZE+8+4*4)(%esp)
 315         CFI_ADJUST_CFA_OFFSET 4
 316         CFI_REL_OFFSET eip, 0
 317
 318 /*
 319  * Load the potential sixth argument from user stack.
 320  * Careful about security.
 321  */
 322         cmpl $__PAGE_OFFSET-3,%ebp
 323         jae syscall_fault
 324 1:      movl (%ebp),%ebp
 325 .section __ex_table,"a"
 326         .align 4
 327         .long 1b,syscall_fault
 328 .previous
 329
 330         pushl %eax
 331         CFI_ADJUST_CFA_OFFSET 4
 332         SAVE_ALL
 333         GET_THREAD_INFO(%ebp)
 334
 335         /* Note, _TIF_SECCOMP is bit number 8, and so it needs testw and not testb */
 336         testw $(_TIF_SYSCALL_EMU|_TIF_SYSCALL_TRACE|_TIF_SECCOMP|_TIF_SYSCALL_AUDIT),TI_flags(%ebp)
 337         jnz syscall_trace_entry
 338         cmpl $(nr_syscalls), %eax
 339         jae syscall_badsys
 340         call *sys_call_table(,%eax,4)
 341         movl %eax,PT_EAX(%esp)
 342         LOCKDEP_SYS_EXIT
 343         DISABLE_INTERRUPTS(CLBR_ANY)
 344         TRACE_IRQS_OFF
 345         movl TI_flags(%ebp), %ecx
 346         testw $_TIF_ALLWORK_MASK, %cx
 347         jne syscall_exit_work
 348 /* if something modifies registers it must also disable sysexit */
 349         movl PT_EIP(%esp), %edx
 350         movl PT_OLDESP(%esp), %ecx
 351         xorl %ebp,%ebp
 352         TRACE_IRQS_ON
 353 1:      mov  PT_FS(%esp), %fs
 354         ENABLE_INTERRUPTS_SYSEXIT
 355         CFI_ENDPROC
 356 .pushsection .fixup,"ax"
 357 2:      movl $0,PT_FS(%esp)
 358         jmp 1b
 359 .section __ex_table,"a"
 360         .align 4
 361         .long 1b,2b
 362 .popsection
 363 ENDPROC(sysenter_entry)
 364
 365         # system call handler stub
 366 ENTRY(system_call)
 367         RING0_INT_FRAME                 # can't unwind into user space anyway
 368         pushl %eax                      # save orig_eax
 369         CFI_ADJUST_CFA_OFFSET 4
 370         SAVE_ALL
 371         GET_THREAD_INFO(%ebp)
 372                                         # system call tracing in operation / emulation
 373         /* Note, _TIF_SECCOMP is bit number 8, and so it needs testw and not testb */
 374         testw $(_TIF_SYSCALL_EMU|_TIF_SYSCALL_TRACE|_TIF_SECCOMP|_TIF_SYSCALL_AUDIT),TI_flags(%ebp)
 375         jnz syscall_trace_entry
 376         cmpl $(nr_syscalls), %eax
 377         jae syscall_badsys
 378 syscall_call:
 379         call *sys_call_table(,%eax,4)
 380         movl %eax,PT_EAX(%esp)          # store the return value
 381 syscall_exit:
 382         LOCKDEP_SYS_EXIT
 383         DISABLE_INTERRUPTS(CLBR_ANY)    # make sure we don't miss an interrupt
 384                                         # setting need_resched or sigpending
 385                                         # between sampling and the iret
 386         TRACE_IRQS_OFF
 387         testl $TF_MASK,PT_EFLAGS(%esp)  # If tracing set singlestep flag on exit
 388         jz no_singlestep
 389         orl $_TIF_SINGLESTEP,TI_flags(%ebp)
 390 no_singlestep:
 391         movl TI_flags(%ebp), %ecx
 392         testw $_TIF_ALLWORK_MASK, %cx   # current->work
 393         jne syscall_exit_work
 394
 395 restore_all:
 396         movl PT_EFLAGS(%esp), %eax      # mix EFLAGS, SS and CS
 397         # Warning: PT_OLDSS(%esp) contains the wrong/random values if we
 398         # are returning to the kernel.
 399         # See comments in process.c:copy_thread() for details.
 400         movb PT_OLDSS(%esp), %ah
 401         movb PT_CS(%esp), %al
 402         andl $(VM_MASK | (SEGMENT_TI_MASK << 8) | SEGMENT_RPL_MASK), %eax
 403         cmpl $((SEGMENT_LDT << 8) | USER_RPL), %eax
 404         CFI_REMEMBER_STATE
 405         je ldt_ss                       # returning to user-space with LDT SS
 406 restore_nocheck:
 407         TRACE_IRQS_IRET
 408 restore_nocheck_notrace:
 409         RESTORE_REGS
 410         addl $4, %esp                   # skip orig_eax/error_code
 411         CFI_ADJUST_CFA_OFFSET -4
 412 1:      INTERRUPT_RETURN
 413 .section .fixup,"ax"
 414 iret_exc:
 415         pushl $0                        # no error code
 416         pushl $do_iret_error
 417         jmp error_code
 418 .previous
 419 .section __ex_table,"a"
 420         .align 4
 421         .long 1b,iret_exc
 422 .previous
 423
 424         CFI_RESTORE_STATE
 425 ldt_ss:
 426         larl PT_OLDSS(%esp), %eax
 427         jnz restore_nocheck
 428         testl $0x00400000, %eax         # returning to 32bit stack?
 429         jnz restore_nocheck             # allright, normal return
 430
 431 #ifdef CONFIG_PARAVIRT
 432         /*
 433          * The kernel can't run on a non-flat stack if paravirt mode
 434          * is active.  Rather than try to fixup the high bits of
 435          * ESP, bypass this code entirely.  This may break DOSemu
 436          * and/or Wine support in a paravirt VM, although the option
 437          * is still available to implement the setting of the high
 438          * 16-bits in the INTERRUPT_RETURN paravirt-op.
 439          */
 440         cmpl $0, paravirt_ops+PARAVIRT_enabled
 441         jne restore_nocheck
 442 #endif
 443
 444         /* If returning to userspace with 16bit stack,
 445          * try to fix the higher word of ESP, as the CPU
 446          * won't restore it.
 447          * This is an "official" bug of all the x86-compatible
 448          * CPUs, which we can try to work around to make
 449          * dosemu and wine happy. */
 450         movl PT_OLDESP(%esp), %eax
 451         movl %esp, %edx
 452         call patch_espfix_desc
 453         pushl $__ESPFIX_SS
 454         CFI_ADJUST_CFA_OFFSET 4
 455         pushl %eax
 456         CFI_ADJUST_CFA_OFFSET 4
 457         DISABLE_INTERRUPTS(CLBR_EAX)
 458         TRACE_IRQS_OFF
 459         lss (%esp), %esp
 460         CFI_ADJUST_CFA_OFFSET -8
 461         jmp restore_nocheck
 462         CFI_ENDPROC
 463 ENDPROC(system_call)
 464
 465         # perform work that needs to be done immediately before resumption
 466         ALIGN
 467         RING0_PTREGS_FRAME              # can't unwind into user space anyway
 468 work_pending:
 469         testb $_TIF_NEED_RESCHED, %cl
 470         jz work_notifysig
 471 work_resched:
 472         call schedule
 473         LOCKDEP_SYS_EXIT
 474         DISABLE_INTERRUPTS(CLBR_ANY)    # make sure we don't miss an interrupt
 475                                         # setting need_resched or sigpending
 476                                         # between sampling and the iret
 477         TRACE_IRQS_OFF
 478         movl TI_flags(%ebp), %ecx
 479         andl $_TIF_WORK_MASK, %ecx      # is there any work to be done other
 480                                         # than syscall tracing?
 481         jz restore_all
 482         testb $_TIF_NEED_RESCHED, %cl
 483         jnz work_resched
 484
 485 work_notifysig:                         # deal with pending signals and
 486                                         # notify-resume requests
 487 #ifdef CONFIG_VM86
 488         testl $VM_MASK, PT_EFLAGS(%esp)
 489         movl %esp, %eax
 490         jne work_notifysig_v86          # returning to kernel-space or
 491                                         # vm86-space
 492         xorl %edx, %edx
 493         call do_notify_resume
 494         jmp resume_userspace_sig
 495
 496         ALIGN
 497 work_notifysig_v86:
 498         pushl %ecx                      # save ti_flags for do_notify_resume
 499         CFI_ADJUST_CFA_OFFSET 4
 500         call save_v86_state             # %eax contains pt_regs pointer
 501         popl %ecx
 502         CFI_ADJUST_CFA_OFFSET -4
 503         movl %eax, %esp
 504 #else
 505         movl %esp, %eax
 506 #endif
 507         xorl %edx, %edx
 508         call do_notify_resume
 509         jmp resume_userspace_sig
 510 END(work_pending)
 511
 512         # perform syscall exit tracing
 513         ALIGN
 514 syscall_trace_entry:
 515         movl $-ENOSYS,PT_EAX(%esp)
 516         movl %esp, %eax
 517         xorl %edx,%edx
 518         call do_syscall_trace
 519         cmpl $0, %eax
 520         jne resume_userspace            # ret != 0 -> running under PTRACE_SYSEMU,
 521                                         # so must skip actual syscall
 522         movl PT_ORIG_EAX(%esp), %eax
 523         cmpl $(nr_syscalls), %eax
 524         jnae syscall_call
 525         jmp syscall_exit
 526 END(syscall_trace_entry)
 527
 528         # perform syscall exit tracing
 529         ALIGN
 530 syscall_exit_work:
 531         testb $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP), %cl
 532         jz work_pending
 533         TRACE_IRQS_ON
 534         ENABLE_INTERRUPTS(CLBR_ANY)     # could let do_syscall_trace() call
 535                                         # schedule() instead
 536         movl %esp, %eax
 537         movl $1, %edx
 538         call do_syscall_trace
 539         jmp resume_userspace
 540 END(syscall_exit_work)
 541         CFI_ENDPROC
 542
 543         RING0_INT_FRAME                 # can't unwind into user space anyway
 544 syscall_fault:
 545         pushl %eax                      # save orig_eax
 546         CFI_ADJUST_CFA_OFFSET 4
 547         SAVE_ALL
 548         GET_THREAD_INFO(%ebp)
 549         movl $-EFAULT,PT_EAX(%esp)
 550         jmp resume_userspace
 551 END(syscall_fault)
 552
 553 syscall_badsys:
 554         movl $-ENOSYS,PT_EAX(%esp)
 555         jmp resume_userspace
 556 END(syscall_badsys)
 557         CFI_ENDPROC
 558
 559 #define FIXUP_ESPFIX_STACK \
 560         /* since we are on a wrong stack, we cant make it a C code :( */ \
 561         PER_CPU(gdt_page, %ebx); \
 562         GET_DESC_BASE(GDT_ENTRY_ESPFIX_SS, %ebx, %eax, %ax, %al, %ah); \
 563         addl %esp, %eax; \
 564         pushl $__KERNEL_DS; \
 565         CFI_ADJUST_CFA_OFFSET 4; \
 566         pushl %eax; \
 567         CFI_ADJUST_CFA_OFFSET 4; \
 568         lss (%esp), %esp; \
 569         CFI_ADJUST_CFA_OFFSET -8;
 570 #define UNWIND_ESPFIX_STACK \
 571         movl %ss, %eax; \
 572         /* see if on espfix stack */ \
 573         cmpw $__ESPFIX_SS, %ax; \
 574         jne 27f; \
 575         movl $__KERNEL_DS, %eax; \
 576         movl %eax, %ds; \
 577         movl %eax, %es; \
 578         /* switch to normal stack */ \
 579         FIXUP_ESPFIX_STACK; \
 580 27:;
 581
 582 /*
 583  * Build the entry stubs and pointer table with
 584  * some assembler magic.
 585  */
 586 .data
 587 ENTRY(interrupt)
 588 .text
 589
 590 ENTRY(irq_entries_start)
 591         RING0_INT_FRAME
 592 vector=0
 593 .rept NR_IRQS
 594         ALIGN
 595  .if vector
 596         CFI_ADJUST_CFA_OFFSET -4
 597  .endif
 598 1:      pushl $~(vector)
 599         CFI_ADJUST_CFA_OFFSET 4
 600         jmp common_interrupt
 601  .previous
 602         .long 1b
 603  .text
 604 vector=vector+1
 605 .endr
 606 END(irq_entries_start)
 607
 608 .previous
 609 END(interrupt)
 610 .previous
 611
 612 /*
 613  * the CPU automatically disables interrupts when executing an IRQ vector,
 614  * so IRQ-flags tracing has to follow that:
 615  */
 616         ALIGN
 617 common_interrupt:
 618         SAVE_ALL
 619         TRACE_IRQS_OFF
 620         movl %esp,%eax
 621         call do_IRQ
 622         jmp ret_from_intr
 623 ENDPROC(common_interrupt)
 624         CFI_ENDPROC
 625
 626 #define BUILD_INTERRUPT(name, nr)       \
 627 ENTRY(name)                             \
 628         RING0_INT_FRAME;                \
 629         pushl $~(nr);                   \
 630         CFI_ADJUST_CFA_OFFSET 4;        \
 631         SAVE_ALL;                       \
 632         TRACE_IRQS_OFF                  \
 633         movl %esp,%eax;                 \
 634         call smp_##name;                \
 635         jmp ret_from_intr;              \
 636         CFI_ENDPROC;                    \
 637 ENDPROC(name)
 638
 639 /* The include is where all of the SMP etc. interrupts come from */
 640 #include "entry_arch.h"
 641
 642 KPROBE_ENTRY(page_fault)
 643         RING0_EC_FRAME
 644         pushl $do_page_fault
 645         CFI_ADJUST_CFA_OFFSET 4
 646         ALIGN
 647 error_code:
 648         /* the function address is in %fs's slot on the stack */
 649         pushl %es
 650         CFI_ADJUST_CFA_OFFSET 4
 651         /*CFI_REL_OFFSET es, 0*/
 652         pushl %ds
 653         CFI_ADJUST_CFA_OFFSET 4
 654         /*CFI_REL_OFFSET ds, 0*/
 655         pushl %eax
 656         CFI_ADJUST_CFA_OFFSET 4
 657         CFI_REL_OFFSET eax, 0
 658         pushl %ebp
 659         CFI_ADJUST_CFA_OFFSET 4
 660         CFI_REL_OFFSET ebp, 0
 661         pushl %edi
 662         CFI_ADJUST_CFA_OFFSET 4
 663         CFI_REL_OFFSET edi, 0
 664         pushl %esi
 665         CFI_ADJUST_CFA_OFFSET 4
 666         CFI_REL_OFFSET esi, 0
 667         pushl %edx
 668         CFI_ADJUST_CFA_OFFSET 4
 669         CFI_REL_OFFSET edx, 0
 670         pushl %ecx
 671         CFI_ADJUST_CFA_OFFSET 4
 672         CFI_REL_OFFSET ecx, 0
 673         pushl %ebx
 674         CFI_ADJUST_CFA_OFFSET 4
 675         CFI_REL_OFFSET ebx, 0
 676         cld
 677         pushl %fs
 678         CFI_ADJUST_CFA_OFFSET 4
 679         /*CFI_REL_OFFSET fs, 0*/
 680         movl $(__KERNEL_PERCPU), %ecx
 681         movl %ecx, %fs
 682         UNWIND_ESPFIX_STACK
 683         popl %ecx
 684         CFI_ADJUST_CFA_OFFSET -4
 685         /*CFI_REGISTER es, ecx*/
 686         movl PT_FS(%esp), %edi          # get the function address
 687         movl PT_ORIG_EAX(%esp), %edx    # get the error code
 688         movl $-1, PT_ORIG_EAX(%esp)     # no syscall to restart
 689         mov  %ecx, PT_FS(%esp)
 690         /*CFI_REL_OFFSET fs, ES*/
 691         movl $(__USER_DS), %ecx
 692         movl %ecx, %ds
 693         movl %ecx, %es
 694         movl %esp,%eax                  # pt_regs pointer
 695         call *%edi
 696         jmp ret_from_exception
 697         CFI_ENDPROC
 698 KPROBE_END(page_fault)
 699
 700 ENTRY(coprocessor_error)
 701         RING0_INT_FRAME
 702         pushl $0
 703         CFI_ADJUST_CFA_OFFSET 4
 704         pushl $do_coprocessor_error
 705         CFI_ADJUST_CFA_OFFSET 4
 706         jmp error_code
 707         CFI_ENDPROC
 708 END(coprocessor_error)
 709
 710 ENTRY(simd_coprocessor_error)
 711         RING0_INT_FRAME
 712         pushl $0
 713         CFI_ADJUST_CFA_OFFSET 4
 714         pushl $do_simd_coprocessor_error
 715         CFI_ADJUST_CFA_OFFSET 4
 716         jmp error_code
 717         CFI_ENDPROC
 718 END(simd_coprocessor_error)
 719
 720 ENTRY(device_not_available)
 721         RING0_INT_FRAME
 722         pushl $-1                       # mark this as an int
 723         CFI_ADJUST_CFA_OFFSET 4
 724         SAVE_ALL
 725         GET_CR0_INTO_EAX
 726         testl $0x4, %eax                # EM (math emulation bit)
 727         jne device_not_available_emulate
 728         preempt_stop(CLBR_ANY)
 729         call math_state_restore
 730         jmp ret_from_exception
 731 device_not_available_emulate:
 732         pushl $0                        # temporary storage for ORIG_EIP
 733         CFI_ADJUST_CFA_OFFSET 4
 734         call math_emulate
 735         addl $4, %esp
 736         CFI_ADJUST_CFA_OFFSET -4
 737         jmp ret_from_exception
 738         CFI_ENDPROC
 739 END(device_not_available)
 740
 741 /*
 742  * Debug traps and NMI can happen at the one SYSENTER instruction
 743  * that sets up the real kernel stack. Check here, since we can't
 744  * allow the wrong stack to be used.
 745  *
 746  * "TSS_sysenter_esp0+12" is because the NMI/debug handler will have
 747  * already pushed 3 words if it hits on the sysenter instruction:
 748  * eflags, cs and eip.
 749  *
 750  * We just load the right stack, and push the three (known) values
 751  * by hand onto the new stack - while updating the return eip past
 752  * the instruction that would have done it for sysenter.
 753  */
 754 #define FIX_STACK(offset, ok, label)            \
 755         cmpw $__KERNEL_CS,4(%esp);              \
 756         jne ok;                                 \
 757 label:                                          \
 758         movl TSS_sysenter_esp0+offset(%esp),%esp;       \
 759         CFI_DEF_CFA esp, 0;                     \
 760         CFI_UNDEFINED eip;                      \
 761         pushfl;                                 \
 762         CFI_ADJUST_CFA_OFFSET 4;                \
 763         pushl $__KERNEL_CS;                     \
 764         CFI_ADJUST_CFA_OFFSET 4;                \
 765         pushl $sysenter_past_esp;               \
 766         CFI_ADJUST_CFA_OFFSET 4;                \
 767         CFI_REL_OFFSET eip, 0
 768
 769 KPROBE_ENTRY(debug)
 770         RING0_INT_FRAME
 771         cmpl $sysenter_entry,(%esp)
 772         jne debug_stack_correct
 773         FIX_STACK(12, debug_stack_correct, debug_esp_fix_insn)
 774 debug_stack_correct:
 775         pushl $-1                       # mark this as an int
 776         CFI_ADJUST_CFA_OFFSET 4
 777         SAVE_ALL
 778         xorl %edx,%edx                  # error code 0
 779         movl %esp,%eax                  # pt_regs pointer
 780         call do_debug
 781         jmp ret_from_exception
 782         CFI_ENDPROC
 783 KPROBE_END(debug)
 784
 785 /*
 786  * NMI is doubly nasty. It can happen _while_ we're handling
 787  * a debug fault, and the debug fault hasn't yet been able to
 788  * clear up the stack. So we first check whether we got  an
 789  * NMI on the sysenter entry path, but after that we need to
 790  * check whether we got an NMI on the debug path where the debug
 791  * fault happened on the sysenter path.
 792  */
 793 KPROBE_ENTRY(nmi)
 794         RING0_INT_FRAME
 795         pushl %eax
 796         CFI_ADJUST_CFA_OFFSET 4
 797         movl %ss, %eax
 798         cmpw $__ESPFIX_SS, %ax
 799         popl %eax
 800         CFI_ADJUST_CFA_OFFSET -4
 801         je nmi_espfix_stack
 802         cmpl $sysenter_entry,(%esp)
 803         je nmi_stack_fixup
 804         pushl %eax
 805         CFI_ADJUST_CFA_OFFSET 4
 806         movl %esp,%eax
 807         /* Do not access memory above the end of our stack page,
 808          * it might not exist.
 809          */
 810         andl $(THREAD_SIZE-1),%eax
 811         cmpl $(THREAD_SIZE-20),%eax
 812         popl %eax
 813         CFI_ADJUST_CFA_OFFSET -4
 814         jae nmi_stack_correct
 815         cmpl $sysenter_entry,12(%esp)
 816         je nmi_debug_stack_check
 817 nmi_stack_correct:
 818         /* We have a RING0_INT_FRAME here */
 819         pushl %eax
 820         CFI_ADJUST_CFA_OFFSET 4
 821         SAVE_ALL
 822         xorl %edx,%edx          # zero error code
 823         movl %esp,%eax          # pt_regs pointer
 824         call do_nmi
 825         jmp restore_nocheck_notrace
 826         CFI_ENDPROC
 827
 828 nmi_stack_fixup:
 829         RING0_INT_FRAME
 830         FIX_STACK(12,nmi_stack_correct, 1)
 831         jmp nmi_stack_correct
 832
 833 nmi_debug_stack_check:
 834         /* We have a RING0_INT_FRAME here */
 835         cmpw $__KERNEL_CS,16(%esp)
 836         jne nmi_stack_correct
 837         cmpl $debug,(%esp)
 838         jb nmi_stack_correct
 839         cmpl $debug_esp_fix_insn,(%esp)
 840         ja nmi_stack_correct
 841         FIX_STACK(24,nmi_stack_correct, 1)
 842         jmp nmi_stack_correct
 843
 844 nmi_espfix_stack:
 845         /* We have a RING0_INT_FRAME here.
 846          *
 847          * create the pointer to lss back
 848          */
 849         pushl %ss
 850         CFI_ADJUST_CFA_OFFSET 4
 851         pushl %esp
 852         CFI_ADJUST_CFA_OFFSET 4
 853         addw $4, (%esp)
 854         /* copy the iret frame of 12 bytes */
 855         .rept 3
 856         pushl 16(%esp)
 857         CFI_ADJUST_CFA_OFFSET 4
 858         .endr
 859         pushl %eax
 860         CFI_ADJUST_CFA_OFFSET 4
 861         SAVE_ALL
 862         FIXUP_ESPFIX_STACK              # %eax == %esp
 863         xorl %edx,%edx                  # zero error code
 864         call do_nmi
 865         RESTORE_REGS
 866         lss 12+4(%esp), %esp            # back to espfix stack
 867         CFI_ADJUST_CFA_OFFSET -24
 868 1:      INTERRUPT_RETURN
 869         CFI_ENDPROC
 870 .section __ex_table,"a"
 871         .align 4
 872         .long 1b,iret_exc
 873 .previous
 874 KPROBE_END(nmi)
 875
 876 #ifdef CONFIG_PARAVIRT
 877 ENTRY(native_iret)
 878 1:      iret
 879 .section __ex_table,"a"
 880         .align 4
 881         .long 1b,iret_exc
 882 .previous
 883 END(native_iret)
 884
 885 ENTRY(native_irq_enable_sysexit)
 886         sti
 887         sysexit
 888 END(native_irq_enable_sysexit)
 889 #endif
 890
 891 KPROBE_ENTRY(int3)
 892         RING0_INT_FRAME
 893         pushl $-1                       # mark this as an int
 894         CFI_ADJUST_CFA_OFFSET 4
 895         SAVE_ALL
 896         xorl %edx,%edx          # zero error code
 897         movl %esp,%eax          # pt_regs pointer
 898         call do_int3
 899         jmp ret_from_exception
 900         CFI_ENDPROC
 901 KPROBE_END(int3)
 902
 903 ENTRY(overflow)
 904         RING0_INT_FRAME
 905         pushl $0
 906         CFI_ADJUST_CFA_OFFSET 4
 907         pushl $do_overflow
 908         CFI_ADJUST_CFA_OFFSET 4
 909         jmp error_code
 910         CFI_ENDPROC
 911 END(overflow)
 912
 913 ENTRY(bounds)
 914         RING0_INT_FRAME
 915         pushl $0
 916         CFI_ADJUST_CFA_OFFSET 4
 917         pushl $do_bounds
 918         CFI_ADJUST_CFA_OFFSET 4
 919         jmp error_code
 920         CFI_ENDPROC
 921 END(bounds)
 922
 923 ENTRY(invalid_op)
 924         RING0_INT_FRAME
 925         pushl $0
 926         CFI_ADJUST_CFA_OFFSET 4
 927         pushl $do_invalid_op
 928         CFI_ADJUST_CFA_OFFSET 4
 929         jmp error_code
 930         CFI_ENDPROC
 931 END(invalid_op)
 932
 933 ENTRY(coprocessor_segment_overrun)
 934         RING0_INT_FRAME
 935         pushl $0
 936         CFI_ADJUST_CFA_OFFSET 4
 937         pushl $do_coprocessor_segment_overrun
 938         CFI_ADJUST_CFA_OFFSET 4
 939         jmp error_code
 940         CFI_ENDPROC
 941 END(coprocessor_segment_overrun)
 942
 943 ENTRY(invalid_TSS)
 944         RING0_EC_FRAME
 945         pushl $do_invalid_TSS
 946         CFI_ADJUST_CFA_OFFSET 4
 947         jmp error_code
 948         CFI_ENDPROC
 949 END(invalid_TSS)
 950
 951 ENTRY(segment_not_present)
 952         RING0_EC_FRAME
 953         pushl $do_segment_not_present
 954         CFI_ADJUST_CFA_OFFSET 4
 955         jmp error_code
 956         CFI_ENDPROC
 957 END(segment_not_present)
 958
 959 ENTRY(stack_segment)
 960         RING0_EC_FRAME
 961         pushl $do_stack_segment
 962         CFI_ADJUST_CFA_OFFSET 4
 963         jmp error_code
 964         CFI_ENDPROC
 965 END(stack_segment)
 966
 967 KPROBE_ENTRY(general_protection)
 968         RING0_EC_FRAME
 969         pushl $do_general_protection
 970         CFI_ADJUST_CFA_OFFSET 4
 971         jmp error_code
 972         CFI_ENDPROC
 973 KPROBE_END(general_protection)
 974
 975 ENTRY(alignment_check)
 976         RING0_EC_FRAME
 977         pushl $do_alignment_check
 978         CFI_ADJUST_CFA_OFFSET 4
 979         jmp error_code
 980         CFI_ENDPROC
 981 END(alignment_check)
 982
 983 ENTRY(divide_error)
 984         RING0_INT_FRAME
 985         pushl $0                        # no error code
 986         CFI_ADJUST_CFA_OFFSET 4
 987         pushl $do_divide_error
 988         CFI_ADJUST_CFA_OFFSET 4
 989         jmp error_code
 990         CFI_ENDPROC
 991 END(divide_error)
 992
 993 #ifdef CONFIG_X86_MCE
 994 ENTRY(machine_check)
 995         RING0_INT_FRAME
 996         pushl $0
 997         CFI_ADJUST_CFA_OFFSET 4
 998         pushl machine_check_vector
 999         CFI_ADJUST_CFA_OFFSET 4
1000         jmp error_code
1001         CFI_ENDPROC
1002 END(machine_check)
1003 #endif
1004
1005 ENTRY(spurious_interrupt_bug)
1006         RING0_INT_FRAME
1007         pushl $0
1008         CFI_ADJUST_CFA_OFFSET 4
1009         pushl $do_spurious_interrupt_bug
1010         CFI_ADJUST_CFA_OFFSET 4
1011         jmp error_code
1012         CFI_ENDPROC
1013 END(spurious_interrupt_bug)
1014
1015 ENTRY(kernel_thread_helper)
1016         pushl $0                # fake return address for unwinder
1017         CFI_STARTPROC
1018         movl %edx,%eax
1019         push %edx
1020         CFI_ADJUST_CFA_OFFSET 4
1021         call *%ebx
1022         push %eax
1023         CFI_ADJUST_CFA_OFFSET 4
1024         call do_exit
1025         CFI_ENDPROC
1026 ENDPROC(kernel_thread_helper)
1027
1028 #ifdef CONFIG_XEN
1029 ENTRY(xen_hypervisor_callback)
1030         CFI_STARTPROC
1031         pushl $0
1032         CFI_ADJUST_CFA_OFFSET 4
1033         SAVE_ALL
1034         TRACE_IRQS_OFF
1035
1036         /* Check to see if we got the event in the critical
1037            region in xen_iret_direct, after we've reenabled
1038            events and checked for pending events.  This simulates
1039            iret instruction's behaviour where it delivers a
1040            pending interrupt when enabling interrupts. */
1041         movl PT_EIP(%esp),%eax
1042         cmpl $xen_iret_start_crit,%eax
1043         jb   1f
1044         cmpl $xen_iret_end_crit,%eax
1045         jae  1f
1046
1047         call xen_iret_crit_fixup
1048
1049 1:      mov %esp, %eax
1050         call xen_evtchn_do_upcall
1051         jmp  ret_from_intr
1052         CFI_ENDPROC
1053 ENDPROC(xen_hypervisor_callback)
1054
1055 # Hypervisor uses this for application faults while it executes.
1056 # We get here for two reasons:
1057 #  1. Fault while reloading DS, ES, FS or GS
1058 #  2. Fault while executing IRET
1059 # Category 1 we fix up by reattempting the load, and zeroing the segment
1060 # register if the load fails.
1061 # Category 2 we fix up by jumping to do_iret_error. We cannot use the
1062 # normal Linux return path in this case because if we use the IRET hypercall
1063 # to pop the stack frame we end up in an infinite loop of failsafe callbacks.
1064 # We distinguish between categories by maintaining a status value in EAX.
1065 ENTRY(xen_failsafe_callback)
1066         CFI_STARTPROC
1067         pushl %eax
1068         CFI_ADJUST_CFA_OFFSET 4
1069         movl $1,%eax
1070 1:      mov 4(%esp),%ds
1071 2:      mov 8(%esp),%es
1072 3:      mov 12(%esp),%fs
1073 4:      mov 16(%esp),%gs
1074         testl %eax,%eax
1075         popl %eax
1076         CFI_ADJUST_CFA_OFFSET -4
1077         lea 16(%esp),%esp
1078         CFI_ADJUST_CFA_OFFSET -16
1079         jz 5f
1080         addl $16,%esp
1081         jmp iret_exc            # EAX != 0 => Category 2 (Bad IRET)
1082 5:      pushl $0                # EAX == 0 => Category 1 (Bad segment)
1083         CFI_ADJUST_CFA_OFFSET 4
1084         SAVE_ALL
1085         jmp ret_from_exception
1086         CFI_ENDPROC
1087
1088 .section .fixup,"ax"
1089 6:      xorl %eax,%eax
1090         movl %eax,4(%esp)
1091         jmp 1b
1092 7:      xorl %eax,%eax
1093         movl %eax,8(%esp)
1094         jmp 2b
1095 8:      xorl %eax,%eax
1096         movl %eax,12(%esp)
1097         jmp 3b
1098 9:      xorl %eax,%eax
1099         movl %eax,16(%esp)
1100         jmp 4b
1101 .previous
1102 .section __ex_table,"a"
1103         .align 4
1104         .long 1b,6b
1105         .long 2b,7b
1106         .long 3b,8b
1107         .long 4b,9b
1108 .previous
1109 ENDPROC(xen_failsafe_callback)
1110
1111 #endif  /* CONFIG_XEN */
1112
1113 .section .rodata,"a"
1114 #include "syscall_table_32.S"
1115
1116 syscall_table_size=(.-sys_call_table)