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_SYSCALL_RET (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(ia32_sysenter_target)
 287         CFI_STARTPROC simple
 288         CFI_SIGNAL_FRAME
 289         CFI_DEF_CFA esp, 0
 290         CFI_REGISTER esp, ebp
 291         movl TSS_sysenter_sp0(%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_SYSCALL_RET
 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(ia32_sysenter_target)
 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 irq_return:
 413         INTERRUPT_RETURN
 414 .section .fixup,"ax"
 415 iret_exc:
 416         pushl $0                        # no error code
 417         pushl $do_iret_error
 418         jmp error_code
 419 .previous
 420 .section __ex_table,"a"
 421         .align 4
 422         .long irq_return,iret_exc
 423 .previous
 424
 425         CFI_RESTORE_STATE
 426 ldt_ss:
 427         larl PT_OLDSS(%esp), %eax
 428         jnz restore_nocheck
 429         testl $0x00400000, %eax         # returning to 32bit stack?
 430         jnz restore_nocheck             # allright, normal return
 431
 432 #ifdef CONFIG_PARAVIRT
 433         /*
 434          * The kernel can't run on a non-flat stack if paravirt mode
 435          * is active.  Rather than try to fixup the high bits of
 436          * ESP, bypass this code entirely.  This may break DOSemu
 437          * and/or Wine support in a paravirt VM, although the option
 438          * is still available to implement the setting of the high
 439          * 16-bits in the INTERRUPT_RETURN paravirt-op.
 440          */
 441         cmpl $0, pv_info+PARAVIRT_enabled
 442         jne restore_nocheck
 443 #endif
 444
 445         /* If returning to userspace with 16bit stack,
 446          * try to fix the higher word of ESP, as the CPU
 447          * won't restore it.
 448          * This is an "official" bug of all the x86-compatible
 449          * CPUs, which we can try to work around to make
 450          * dosemu and wine happy. */
 451         movl PT_OLDESP(%esp), %eax
 452         movl %esp, %edx
 453         call patch_espfix_desc
 454         pushl $__ESPFIX_SS
 455         CFI_ADJUST_CFA_OFFSET 4
 456         pushl %eax
 457         CFI_ADJUST_CFA_OFFSET 4
 458         DISABLE_INTERRUPTS(CLBR_EAX)
 459         TRACE_IRQS_OFF
 460         lss (%esp), %esp
 461         CFI_ADJUST_CFA_OFFSET -8
 462         jmp restore_nocheck
 463         CFI_ENDPROC
 464 ENDPROC(system_call)
 465
 466         # perform work that needs to be done immediately before resumption
 467         ALIGN
 468         RING0_PTREGS_FRAME              # can't unwind into user space anyway
 469 work_pending:
 470         testb $_TIF_NEED_RESCHED, %cl
 471         jz work_notifysig
 472 work_resched:
 473         call schedule
 474         LOCKDEP_SYS_EXIT
 475         DISABLE_INTERRUPTS(CLBR_ANY)    # make sure we don't miss an interrupt
 476                                         # setting need_resched or sigpending
 477                                         # between sampling and the iret
 478         TRACE_IRQS_OFF
 479         movl TI_flags(%ebp), %ecx
 480         andl $_TIF_WORK_MASK, %ecx      # is there any work to be done other
 481                                         # than syscall tracing?
 482         jz restore_all
 483         testb $_TIF_NEED_RESCHED, %cl
 484         jnz work_resched
 485
 486 work_notifysig:                         # deal with pending signals and
 487                                         # notify-resume requests
 488 #ifdef CONFIG_VM86
 489         testl $VM_MASK, PT_EFLAGS(%esp)
 490         movl %esp, %eax
 491         jne work_notifysig_v86          # returning to kernel-space or
 492                                         # vm86-space
 493         xorl %edx, %edx
 494         call do_notify_resume
 495         jmp resume_userspace_sig
 496
 497         ALIGN
 498 work_notifysig_v86:
 499         pushl %ecx                      # save ti_flags for do_notify_resume
 500         CFI_ADJUST_CFA_OFFSET 4
 501         call save_v86_state             # %eax contains pt_regs pointer
 502         popl %ecx
 503         CFI_ADJUST_CFA_OFFSET -4
 504         movl %eax, %esp
 505 #else
 506         movl %esp, %eax
 507 #endif
 508         xorl %edx, %edx
 509         call do_notify_resume
 510         jmp resume_userspace_sig
 511 END(work_pending)
 512
 513         # perform syscall exit tracing
 514         ALIGN
 515 syscall_trace_entry:
 516         movl $-ENOSYS,PT_EAX(%esp)
 517         movl %esp, %eax
 518         xorl %edx,%edx
 519         call do_syscall_trace
 520         cmpl $0, %eax
 521         jne resume_userspace            # ret != 0 -> running under PTRACE_SYSEMU,
 522                                         # so must skip actual syscall
 523         movl PT_ORIG_EAX(%esp), %eax
 524         cmpl $(nr_syscalls), %eax
 525         jnae syscall_call
 526         jmp syscall_exit
 527 END(syscall_trace_entry)
 528
 529         # perform syscall exit tracing
 530         ALIGN
 531 syscall_exit_work:
 532         testb $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP), %cl
 533         jz work_pending
 534         TRACE_IRQS_ON
 535         ENABLE_INTERRUPTS(CLBR_ANY)     # could let do_syscall_trace() call
 536                                         # schedule() instead
 537         movl %esp, %eax
 538         movl $1, %edx
 539         call do_syscall_trace
 540         jmp resume_userspace
 541 END(syscall_exit_work)
 542         CFI_ENDPROC
 543
 544         RING0_INT_FRAME                 # can't unwind into user space anyway
 545 syscall_fault:
 546         pushl %eax                      # save orig_eax
 547         CFI_ADJUST_CFA_OFFSET 4
 548         SAVE_ALL
 549         GET_THREAD_INFO(%ebp)
 550         movl $-EFAULT,PT_EAX(%esp)
 551         jmp resume_userspace
 552 END(syscall_fault)
 553
 554 syscall_badsys:
 555         movl $-ENOSYS,PT_EAX(%esp)
 556         jmp resume_userspace
 557 END(syscall_badsys)
 558         CFI_ENDPROC
 559
 560 #define FIXUP_ESPFIX_STACK \
 561         /* since we are on a wrong stack, we cant make it a C code :( */ \
 562         PER_CPU(gdt_page, %ebx); \
 563         GET_DESC_BASE(GDT_ENTRY_ESPFIX_SS, %ebx, %eax, %ax, %al, %ah); \
 564         addl %esp, %eax; \
 565         pushl $__KERNEL_DS; \
 566         CFI_ADJUST_CFA_OFFSET 4; \
 567         pushl %eax; \
 568         CFI_ADJUST_CFA_OFFSET 4; \
 569         lss (%esp), %esp; \
 570         CFI_ADJUST_CFA_OFFSET -8;
 571 #define UNWIND_ESPFIX_STACK \
 572         movl %ss, %eax; \
 573         /* see if on espfix stack */ \
 574         cmpw $__ESPFIX_SS, %ax; \
 575         jne 27f; \
 576         movl $__KERNEL_DS, %eax; \
 577         movl %eax, %ds; \
 578         movl %eax, %es; \
 579         /* switch to normal stack */ \
 580         FIXUP_ESPFIX_STACK; \
 581 27:;
 582
 583 /*
 584  * Build the entry stubs and pointer table with
 585  * some assembler magic.
 586  */
 587 .section .rodata,"a"
 588 ENTRY(interrupt)
 589 .text
 590
 591 ENTRY(irq_entries_start)
 592         RING0_INT_FRAME
 593 vector=0
 594 .rept NR_IRQS
 595         ALIGN
 596  .if vector
 597         CFI_ADJUST_CFA_OFFSET -4
 598  .endif
 599 1:      pushl $~(vector)
 600         CFI_ADJUST_CFA_OFFSET 4
 601         jmp common_interrupt
 602  .previous
 603         .long 1b
 604  .text
 605 vector=vector+1
 606 .endr
 607 END(irq_entries_start)
 608
 609 .previous
 610 END(interrupt)
 611 .previous
 612
 613 /*
 614  * the CPU automatically disables interrupts when executing an IRQ vector,
 615  * so IRQ-flags tracing has to follow that:
 616  */
 617         ALIGN
 618 common_interrupt:
 619         SAVE_ALL
 620         TRACE_IRQS_OFF
 621         movl %esp,%eax
 622         call do_IRQ
 623         jmp ret_from_intr
 624 ENDPROC(common_interrupt)
 625         CFI_ENDPROC
 626
 627 #define BUILD_INTERRUPT(name, nr)       \
 628 ENTRY(name)                             \
 629         RING0_INT_FRAME;                \
 630         pushl $~(nr);                   \
 631         CFI_ADJUST_CFA_OFFSET 4;        \
 632         SAVE_ALL;                       \
 633         TRACE_IRQS_OFF                  \
 634         movl %esp,%eax;                 \
 635         call smp_##name;                \
 636         jmp ret_from_intr;              \
 637         CFI_ENDPROC;                    \
 638 ENDPROC(name)
 639
 640 /* The include is where all of the SMP etc. interrupts come from */
 641 #include "entry_arch.h"
 642
 643 KPROBE_ENTRY(page_fault)
 644         RING0_EC_FRAME
 645         pushl $do_page_fault
 646         CFI_ADJUST_CFA_OFFSET 4
 647         ALIGN
 648 error_code:
 649         /* the function address is in %fs's slot on the stack */
 650         pushl %es
 651         CFI_ADJUST_CFA_OFFSET 4
 652         /*CFI_REL_OFFSET es, 0*/
 653         pushl %ds
 654         CFI_ADJUST_CFA_OFFSET 4
 655         /*CFI_REL_OFFSET ds, 0*/
 656         pushl %eax
 657         CFI_ADJUST_CFA_OFFSET 4
 658         CFI_REL_OFFSET eax, 0
 659         pushl %ebp
 660         CFI_ADJUST_CFA_OFFSET 4
 661         CFI_REL_OFFSET ebp, 0
 662         pushl %edi
 663         CFI_ADJUST_CFA_OFFSET 4
 664         CFI_REL_OFFSET edi, 0
 665         pushl %esi
 666         CFI_ADJUST_CFA_OFFSET 4
 667         CFI_REL_OFFSET esi, 0
 668         pushl %edx
 669         CFI_ADJUST_CFA_OFFSET 4
 670         CFI_REL_OFFSET edx, 0
 671         pushl %ecx
 672         CFI_ADJUST_CFA_OFFSET 4
 673         CFI_REL_OFFSET ecx, 0
 674         pushl %ebx
 675         CFI_ADJUST_CFA_OFFSET 4
 676         CFI_REL_OFFSET ebx, 0
 677         cld
 678         pushl %fs
 679         CFI_ADJUST_CFA_OFFSET 4
 680         /*CFI_REL_OFFSET fs, 0*/
 681         movl $(__KERNEL_PERCPU), %ecx
 682         movl %ecx, %fs
 683         UNWIND_ESPFIX_STACK
 684         popl %ecx
 685         CFI_ADJUST_CFA_OFFSET -4
 686         /*CFI_REGISTER es, ecx*/
 687         movl PT_FS(%esp), %edi          # get the function address
 688         movl PT_ORIG_EAX(%esp), %edx    # get the error code
 689         movl $-1, PT_ORIG_EAX(%esp)     # no syscall to restart
 690         mov  %ecx, PT_FS(%esp)
 691         /*CFI_REL_OFFSET fs, ES*/
 692         movl $(__USER_DS), %ecx
 693         movl %ecx, %ds
 694         movl %ecx, %es
 695         movl %esp,%eax                  # pt_regs pointer
 696         call *%edi
 697         jmp ret_from_exception
 698         CFI_ENDPROC
 699 KPROBE_END(page_fault)
 700
 701 ENTRY(coprocessor_error)
 702         RING0_INT_FRAME
 703         pushl $0
 704         CFI_ADJUST_CFA_OFFSET 4
 705         pushl $do_coprocessor_error
 706         CFI_ADJUST_CFA_OFFSET 4
 707         jmp error_code
 708         CFI_ENDPROC
 709 END(coprocessor_error)
 710
 711 ENTRY(simd_coprocessor_error)
 712         RING0_INT_FRAME
 713         pushl $0
 714         CFI_ADJUST_CFA_OFFSET 4
 715         pushl $do_simd_coprocessor_error
 716         CFI_ADJUST_CFA_OFFSET 4
 717         jmp error_code
 718         CFI_ENDPROC
 719 END(simd_coprocessor_error)
 720
 721 ENTRY(device_not_available)
 722         RING0_INT_FRAME
 723         pushl $-1                       # mark this as an int
 724         CFI_ADJUST_CFA_OFFSET 4
 725         SAVE_ALL
 726         GET_CR0_INTO_EAX
 727         testl $0x4, %eax                # EM (math emulation bit)
 728         jne device_not_available_emulate
 729         preempt_stop(CLBR_ANY)
 730         call math_state_restore
 731         jmp ret_from_exception
 732 device_not_available_emulate:
 733         pushl $0                        # temporary storage for ORIG_EIP
 734         CFI_ADJUST_CFA_OFFSET 4
 735         call math_emulate
 736         addl $4, %esp
 737         CFI_ADJUST_CFA_OFFSET -4
 738         jmp ret_from_exception
 739         CFI_ENDPROC
 740 END(device_not_available)
 741
 742 /*
 743  * Debug traps and NMI can happen at the one SYSENTER instruction
 744  * that sets up the real kernel stack. Check here, since we can't
 745  * allow the wrong stack to be used.
 746  *
 747  * "TSS_sysenter_sp0+12" is because the NMI/debug handler will have
 748  * already pushed 3 words if it hits on the sysenter instruction:
 749  * eflags, cs and eip.
 750  *
 751  * We just load the right stack, and push the three (known) values
 752  * by hand onto the new stack - while updating the return eip past
 753  * the instruction that would have done it for sysenter.
 754  */
 755 #define FIX_STACK(offset, ok, label)            \
 756         cmpw $__KERNEL_CS,4(%esp);              \
 757         jne ok;                                 \
 758 label:                                          \
 759         movl TSS_sysenter_sp0+offset(%esp),%esp;        \
 760         CFI_DEF_CFA esp, 0;                     \
 761         CFI_UNDEFINED eip;                      \
 762         pushfl;                                 \
 763         CFI_ADJUST_CFA_OFFSET 4;                \
 764         pushl $__KERNEL_CS;                     \
 765         CFI_ADJUST_CFA_OFFSET 4;                \
 766         pushl $sysenter_past_esp;               \
 767         CFI_ADJUST_CFA_OFFSET 4;                \
 768         CFI_REL_OFFSET eip, 0
 769
 770 KPROBE_ENTRY(debug)
 771         RING0_INT_FRAME
 772         cmpl $ia32_sysenter_target,(%esp)
 773         jne debug_stack_correct
 774         FIX_STACK(12, debug_stack_correct, debug_esp_fix_insn)
 775 debug_stack_correct:
 776         pushl $-1                       # mark this as an int
 777         CFI_ADJUST_CFA_OFFSET 4
 778         SAVE_ALL
 779         xorl %edx,%edx                  # error code 0
 780         movl %esp,%eax                  # pt_regs pointer
 781         call do_debug
 782         jmp ret_from_exception
 783         CFI_ENDPROC
 784 KPROBE_END(debug)
 785
 786 /*
 787  * NMI is doubly nasty. It can happen _while_ we're handling
 788  * a debug fault, and the debug fault hasn't yet been able to
 789  * clear up the stack. So we first check whether we got  an
 790  * NMI on the sysenter entry path, but after that we need to
 791  * check whether we got an NMI on the debug path where the debug
 792  * fault happened on the sysenter path.
 793  */
 794 KPROBE_ENTRY(nmi)
 795         RING0_INT_FRAME
 796         pushl %eax
 797         CFI_ADJUST_CFA_OFFSET 4
 798         movl %ss, %eax
 799         cmpw $__ESPFIX_SS, %ax
 800         popl %eax
 801         CFI_ADJUST_CFA_OFFSET -4
 802         je nmi_espfix_stack
 803         cmpl $ia32_sysenter_target,(%esp)
 804         je nmi_stack_fixup
 805         pushl %eax
 806         CFI_ADJUST_CFA_OFFSET 4
 807         movl %esp,%eax
 808         /* Do not access memory above the end of our stack page,
 809          * it might not exist.
 810          */
 811         andl $(THREAD_SIZE-1),%eax
 812         cmpl $(THREAD_SIZE-20),%eax
 813         popl %eax
 814         CFI_ADJUST_CFA_OFFSET -4
 815         jae nmi_stack_correct
 816         cmpl $ia32_sysenter_target,12(%esp)
 817         je nmi_debug_stack_check
 818 nmi_stack_correct:
 819         /* We have a RING0_INT_FRAME here */
 820         pushl %eax
 821         CFI_ADJUST_CFA_OFFSET 4
 822         SAVE_ALL
 823         xorl %edx,%edx          # zero error code
 824         movl %esp,%eax          # pt_regs pointer
 825         call do_nmi
 826         jmp restore_nocheck_notrace
 827         CFI_ENDPROC
 828
 829 nmi_stack_fixup:
 830         RING0_INT_FRAME
 831         FIX_STACK(12,nmi_stack_correct, 1)
 832         jmp nmi_stack_correct
 833
 834 nmi_debug_stack_check:
 835         /* We have a RING0_INT_FRAME here */
 836         cmpw $__KERNEL_CS,16(%esp)
 837         jne nmi_stack_correct
 838         cmpl $debug,(%esp)
 839         jb nmi_stack_correct
 840         cmpl $debug_esp_fix_insn,(%esp)
 841         ja nmi_stack_correct
 842         FIX_STACK(24,nmi_stack_correct, 1)
 843         jmp nmi_stack_correct
 844
 845 nmi_espfix_stack:
 846         /* We have a RING0_INT_FRAME here.
 847          *
 848          * create the pointer to lss back
 849          */
 850         pushl %ss
 851         CFI_ADJUST_CFA_OFFSET 4
 852         pushl %esp
 853         CFI_ADJUST_CFA_OFFSET 4
 854         addw $4, (%esp)
 855         /* copy the iret frame of 12 bytes */
 856         .rept 3
 857         pushl 16(%esp)
 858         CFI_ADJUST_CFA_OFFSET 4
 859         .endr
 860         pushl %eax
 861         CFI_ADJUST_CFA_OFFSET 4
 862         SAVE_ALL
 863         FIXUP_ESPFIX_STACK              # %eax == %esp
 864         xorl %edx,%edx                  # zero error code
 865         call do_nmi
 866         RESTORE_REGS
 867         lss 12+4(%esp), %esp            # back to espfix stack
 868         CFI_ADJUST_CFA_OFFSET -24
 869         jmp irq_return
 870         CFI_ENDPROC
 871 KPROBE_END(nmi)
 872
 873 #ifdef CONFIG_PARAVIRT
 874 ENTRY(native_iret)
 875         iret
 876 .section __ex_table,"a"
 877         .align 4
 878         .long native_iret, iret_exc
 879 .previous
 880 END(native_iret)
 881
 882 ENTRY(native_irq_enable_syscall_ret)
 883         sti
 884         sysexit
 885 END(native_irq_enable_syscall_ret)
 886 #endif
 887
 888 KPROBE_ENTRY(int3)
 889         RING0_INT_FRAME
 890         pushl $-1                       # mark this as an int
 891         CFI_ADJUST_CFA_OFFSET 4
 892         SAVE_ALL
 893         xorl %edx,%edx          # zero error code
 894         movl %esp,%eax          # pt_regs pointer
 895         call do_int3
 896         jmp ret_from_exception
 897         CFI_ENDPROC
 898 KPROBE_END(int3)
 899
 900 ENTRY(overflow)
 901         RING0_INT_FRAME
 902         pushl $0
 903         CFI_ADJUST_CFA_OFFSET 4
 904         pushl $do_overflow
 905         CFI_ADJUST_CFA_OFFSET 4
 906         jmp error_code
 907         CFI_ENDPROC
 908 END(overflow)
 909
 910 ENTRY(bounds)
 911         RING0_INT_FRAME
 912         pushl $0
 913         CFI_ADJUST_CFA_OFFSET 4
 914         pushl $do_bounds
 915         CFI_ADJUST_CFA_OFFSET 4
 916         jmp error_code
 917         CFI_ENDPROC
 918 END(bounds)
 919
 920 ENTRY(invalid_op)
 921         RING0_INT_FRAME
 922         pushl $0
 923         CFI_ADJUST_CFA_OFFSET 4
 924         pushl $do_invalid_op
 925         CFI_ADJUST_CFA_OFFSET 4
 926         jmp error_code
 927         CFI_ENDPROC
 928 END(invalid_op)
 929
 930 ENTRY(coprocessor_segment_overrun)
 931         RING0_INT_FRAME
 932         pushl $0
 933         CFI_ADJUST_CFA_OFFSET 4
 934         pushl $do_coprocessor_segment_overrun
 935         CFI_ADJUST_CFA_OFFSET 4
 936         jmp error_code
 937         CFI_ENDPROC
 938 END(coprocessor_segment_overrun)
 939
 940 ENTRY(invalid_TSS)
 941         RING0_EC_FRAME
 942         pushl $do_invalid_TSS
 943         CFI_ADJUST_CFA_OFFSET 4
 944         jmp error_code
 945         CFI_ENDPROC
 946 END(invalid_TSS)
 947
 948 ENTRY(segment_not_present)
 949         RING0_EC_FRAME
 950         pushl $do_segment_not_present
 951         CFI_ADJUST_CFA_OFFSET 4
 952         jmp error_code
 953         CFI_ENDPROC
 954 END(segment_not_present)
 955
 956 ENTRY(stack_segment)
 957         RING0_EC_FRAME
 958         pushl $do_stack_segment
 959         CFI_ADJUST_CFA_OFFSET 4
 960         jmp error_code
 961         CFI_ENDPROC
 962 END(stack_segment)
 963
 964 KPROBE_ENTRY(general_protection)
 965         RING0_EC_FRAME
 966         pushl $do_general_protection
 967         CFI_ADJUST_CFA_OFFSET 4
 968         jmp error_code
 969         CFI_ENDPROC
 970 KPROBE_END(general_protection)
 971
 972 ENTRY(alignment_check)
 973         RING0_EC_FRAME
 974         pushl $do_alignment_check
 975         CFI_ADJUST_CFA_OFFSET 4
 976         jmp error_code
 977         CFI_ENDPROC
 978 END(alignment_check)
 979
 980 ENTRY(divide_error)
 981         RING0_INT_FRAME
 982         pushl $0                        # no error code
 983         CFI_ADJUST_CFA_OFFSET 4
 984         pushl $do_divide_error
 985         CFI_ADJUST_CFA_OFFSET 4
 986         jmp error_code
 987         CFI_ENDPROC
 988 END(divide_error)
 989
 990 #ifdef CONFIG_X86_MCE
 991 ENTRY(machine_check)
 992         RING0_INT_FRAME
 993         pushl $0
 994         CFI_ADJUST_CFA_OFFSET 4
 995         pushl machine_check_vector
 996         CFI_ADJUST_CFA_OFFSET 4
 997         jmp error_code
 998         CFI_ENDPROC
 999 END(machine_check)
1000 #endif
1001
1002 ENTRY(spurious_interrupt_bug)
1003         RING0_INT_FRAME
1004         pushl $0
1005         CFI_ADJUST_CFA_OFFSET 4
1006         pushl $do_spurious_interrupt_bug
1007         CFI_ADJUST_CFA_OFFSET 4
1008         jmp error_code
1009         CFI_ENDPROC
1010 END(spurious_interrupt_bug)
1011
1012 ENTRY(kernel_thread_helper)
1013         pushl $0                # fake return address for unwinder
1014         CFI_STARTPROC
1015         movl %edx,%eax
1016         push %edx
1017         CFI_ADJUST_CFA_OFFSET 4
1018         call *%ebx
1019         push %eax
1020         CFI_ADJUST_CFA_OFFSET 4
1021         call do_exit
1022         CFI_ENDPROC
1023 ENDPROC(kernel_thread_helper)
1024
1025 #ifdef CONFIG_XEN
1026 ENTRY(xen_hypervisor_callback)
1027         CFI_STARTPROC
1028         pushl $0
1029         CFI_ADJUST_CFA_OFFSET 4
1030         SAVE_ALL
1031         TRACE_IRQS_OFF
1032
1033         /* Check to see if we got the event in the critical
1034            region in xen_iret_direct, after we've reenabled
1035            events and checked for pending events.  This simulates
1036            iret instruction's behaviour where it delivers a
1037            pending interrupt when enabling interrupts. */
1038         movl PT_EIP(%esp),%eax
1039         cmpl $xen_iret_start_crit,%eax
1040         jb   1f
1041         cmpl $xen_iret_end_crit,%eax
1042         jae  1f
1043
1044         call xen_iret_crit_fixup
1045
1046 1:      mov %esp, %eax
1047         call xen_evtchn_do_upcall
1048         jmp  ret_from_intr
1049         CFI_ENDPROC
1050 ENDPROC(xen_hypervisor_callback)
1051
1052 # Hypervisor uses this for application faults while it executes.
1053 # We get here for two reasons:
1054 #  1. Fault while reloading DS, ES, FS or GS
1055 #  2. Fault while executing IRET
1056 # Category 1 we fix up by reattempting the load, and zeroing the segment
1057 # register if the load fails.
1058 # Category 2 we fix up by jumping to do_iret_error. We cannot use the
1059 # normal Linux return path in this case because if we use the IRET hypercall
1060 # to pop the stack frame we end up in an infinite loop of failsafe callbacks.
1061 # We distinguish between categories by maintaining a status value in EAX.
1062 ENTRY(xen_failsafe_callback)
1063         CFI_STARTPROC
1064         pushl %eax
1065         CFI_ADJUST_CFA_OFFSET 4
1066         movl $1,%eax
1067 1:      mov 4(%esp),%ds
1068 2:      mov 8(%esp),%es
1069 3:      mov 12(%esp),%fs
1070 4:      mov 16(%esp),%gs
1071         testl %eax,%eax
1072         popl %eax
1073         CFI_ADJUST_CFA_OFFSET -4
1074         lea 16(%esp),%esp
1075         CFI_ADJUST_CFA_OFFSET -16
1076         jz 5f
1077         addl $16,%esp
1078         jmp iret_exc            # EAX != 0 => Category 2 (Bad IRET)
1079 5:      pushl $0                # EAX == 0 => Category 1 (Bad segment)
1080         CFI_ADJUST_CFA_OFFSET 4
1081         SAVE_ALL
1082         jmp ret_from_exception
1083         CFI_ENDPROC
1084
1085 .section .fixup,"ax"
1086 6:      xorl %eax,%eax
1087         movl %eax,4(%esp)
1088         jmp 1b
1089 7:      xorl %eax,%eax
1090         movl %eax,8(%esp)
1091         jmp 2b
1092 8:      xorl %eax,%eax
1093         movl %eax,12(%esp)
1094         jmp 3b
1095 9:      xorl %eax,%eax
1096         movl %eax,16(%esp)
1097         jmp 4b
1098 .previous
1099 .section __ex_table,"a"
1100         .align 4
1101         .long 1b,6b
1102         .long 2b,7b
1103         .long 3b,8b
1104         .long 4b,9b
1105 .previous
1106 ENDPROC(xen_failsafe_callback)
1107
1108 #endif  /* CONFIG_XEN */
1109
1110 .section .rodata,"a"
1111 #include "syscall_table_32.S"
1112
1113 syscall_table_size=(.-sys_call_table)