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