arch/x86/ia32/ia32entry.S

   1 /*
   2  * Compatibility mode system call entry point for x86-64.
   3  *
   4  * Copyright 2000-2002 Andi Kleen, SuSE Labs.
   5  */
   6
   7 #include <asm/dwarf2.h>
   8 #include <asm/calling.h>
   9 #include <asm/asm-offsets.h>
  10 #include <asm/current.h>
  11 #include <asm/errno.h>
  12 #include <asm/ia32_unistd.h>
  13 #include <asm/thread_info.h>
  14 #include <asm/segment.h>
  15 #include <asm/irqflags.h>
  16 #include <asm/asm.h>
  17 #include <asm/smap.h>
  18 #include <linux/linkage.h>
  19 #include <linux/err.h>
  20
  21 /* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this.  */
  22 #include <linux/elf-em.h>
  23 #define AUDIT_ARCH_I386         (EM_386|__AUDIT_ARCH_LE)
  24 #define __AUDIT_ARCH_LE    0x40000000
  25
  26 #ifndef CONFIG_AUDITSYSCALL
  27 #define sysexit_audit ia32_ret_from_sys_call
  28 #define sysretl_audit ia32_ret_from_sys_call
  29 #endif
  30
  31         .section .entry.text, "ax"
  32
  33         .macro IA32_ARG_FIXUP noebp=0
  34         movl    %edi,%r8d
  35         .if \noebp
  36         .else
  37         movl    %ebp,%r9d
  38         .endif
  39         xchg    %ecx,%esi
  40         movl    %ebx,%edi
  41         movl    %edx,%edx       /* zero extension */
  42         .endm
  43
  44         /* clobbers %eax */
  45         .macro  CLEAR_RREGS offset=0, _r9=rax
  46         xorl    %eax,%eax
  47         movq    %rax,\offset+R11(%rsp)
  48         movq    %rax,\offset+R10(%rsp)
  49         movq    %\_r9,\offset+R9(%rsp)
  50         movq    %rax,\offset+R8(%rsp)
  51         .endm
  52
  53         /*
  54          * Reload arg registers from stack in case ptrace changed them.
  55          * We don't reload %eax because syscall_trace_enter() returned
  56          * the %rax value we should see.  Instead, we just truncate that
  57          * value to 32 bits again as we did on entry from user mode.
  58          * If it's a new value set by user_regset during entry tracing,
  59          * this matches the normal truncation of the user-mode value.
  60          * If it's -1 to make us punt the syscall, then (u32)-1 is still
  61          * an appropriately invalid value.
  62          */
  63         .macro LOAD_ARGS32 offset, _r9=0
  64         .if \_r9
  65         movl \offset+16(%rsp),%r9d
  66         .endif
  67         movl \offset+40(%rsp),%ecx
  68         movl \offset+48(%rsp),%edx
  69         movl \offset+56(%rsp),%esi
  70         movl \offset+64(%rsp),%edi
  71         movl %eax,%eax                  /* zero extension */
  72         .endm
  73
  74         .macro CFI_STARTPROC32 simple
  75         CFI_STARTPROC   \simple
  76         CFI_UNDEFINED   r8
  77         CFI_UNDEFINED   r9
  78         CFI_UNDEFINED   r10
  79         CFI_UNDEFINED   r11
  80         CFI_UNDEFINED   r12
  81         CFI_UNDEFINED   r13
  82         CFI_UNDEFINED   r14
  83         CFI_UNDEFINED   r15
  84         .endm
  85
  86 #ifdef CONFIG_PARAVIRT
  87 ENTRY(native_usergs_sysret32)
  88         swapgs
  89         sysretl
  90 ENDPROC(native_usergs_sysret32)
  91
  92 ENTRY(native_irq_enable_sysexit)
  93         swapgs
  94         sti
  95         sysexit
  96 ENDPROC(native_irq_enable_sysexit)
  97 #endif
  98
  99 /*
 100  * 32bit SYSENTER instruction entry.
 101  *
 102  * Arguments:
 103  * %eax System call number.
 104  * %ebx Arg1
 105  * %ecx Arg2
 106  * %edx Arg3
 107  * %esi Arg4
 108  * %edi Arg5
 109  * %ebp user stack
 110  * 0(%ebp) Arg6
 111  *
 112  * Interrupts off.
 113  *
 114  * This is purely a fast path. For anything complicated we use the int 0x80
 115  * path below.  Set up a complete hardware stack frame to share code
 116  * with the int 0x80 path.
 117  */
 118 ENTRY(ia32_sysenter_target)
 119         CFI_STARTPROC32 simple
 120         CFI_SIGNAL_FRAME
 121         CFI_DEF_CFA     rsp,0
 122         CFI_REGISTER    rsp,rbp
 123         SWAPGS_UNSAFE_STACK
 124         movq    PER_CPU_VAR(kernel_stack), %rsp
 125         addq    $(KERNEL_STACK_OFFSET),%rsp
 126         /*
 127          * No need to follow this irqs on/off section: the syscall
 128          * disabled irqs, here we enable it straight after entry:
 129          */
 130         ENABLE_INTERRUPTS(CLBR_NONE)
 131         movl    %ebp,%ebp               /* zero extension */
 132         pushq_cfi $__USER32_DS
 133         /*CFI_REL_OFFSET ss,0*/
 134         pushq_cfi %rbp
 135         CFI_REL_OFFSET rsp,0
 136         pushfq_cfi
 137         /*CFI_REL_OFFSET rflags,0*/
 138         movl    TI_sysenter_return+THREAD_INFO(%rsp,3*8-KERNEL_STACK_OFFSET),%r10d
 139         CFI_REGISTER rip,r10
 140         pushq_cfi $__USER32_CS
 141         /*CFI_REL_OFFSET cs,0*/
 142         movl    %eax, %eax
 143         pushq_cfi %r10
 144         CFI_REL_OFFSET rip,0
 145         pushq_cfi %rax
 146         cld
 147         SAVE_ARGS 0,1,0
 148         /* no need to do an access_ok check here because rbp has been
 149            32bit zero extended */
 150         ASM_STAC
 151 1:      movl    (%rbp),%ebp
 152         _ASM_EXTABLE(1b,ia32_badarg)
 153         ASM_CLAC
 154         orl     $TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP-ARGOFFSET)
 155         testl   $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
 156         CFI_REMEMBER_STATE
 157         jnz  sysenter_tracesys
 158         cmpq    $(IA32_NR_syscalls-1),%rax
 159         ja      ia32_badsys
 160 sysenter_do_call:
 161         IA32_ARG_FIXUP
 162 sysenter_dispatch:
 163         call    *ia32_sys_call_table(,%rax,8)
 164         movq    %rax,RAX-ARGOFFSET(%rsp)
 165         DISABLE_INTERRUPTS(CLBR_NONE)
 166         TRACE_IRQS_OFF
 167         testl   $_TIF_ALLWORK_MASK,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
 168         jnz     sysexit_audit
 169 sysexit_from_sys_call:
 170         andl    $~TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP-ARGOFFSET)
 171         /* clear IF, that popfq doesn't enable interrupts early */
 172         andl  $~0x200,EFLAGS-R11(%rsp)
 173         movl    RIP-R11(%rsp),%edx              /* User %eip */
 174         CFI_REGISTER rip,rdx
 175         RESTORE_ARGS 0,24,0,0,0,0
 176         xorq    %r8,%r8
 177         xorq    %r9,%r9
 178         xorq    %r10,%r10
 179         xorq    %r11,%r11
 180         popfq_cfi
 181         /*CFI_RESTORE rflags*/
 182         popq_cfi %rcx                           /* User %esp */
 183         CFI_REGISTER rsp,rcx
 184         TRACE_IRQS_ON
 185         ENABLE_INTERRUPTS_SYSEXIT32
 186
 187 #ifdef CONFIG_AUDITSYSCALL
 188         .macro auditsys_entry_common
 189         movl %esi,%r9d                  /* 6th arg: 4th syscall arg */
 190         movl %edx,%r8d                  /* 5th arg: 3rd syscall arg */
 191         /* (already in %ecx)               4th arg: 2nd syscall arg */
 192         movl %ebx,%edx                  /* 3rd arg: 1st syscall arg */
 193         movl %eax,%esi                  /* 2nd arg: syscall number */
 194         movl $AUDIT_ARCH_I386,%edi      /* 1st arg: audit arch */
 195         call __audit_syscall_entry
 196         movl RAX-ARGOFFSET(%rsp),%eax   /* reload syscall number */
 197         cmpq $(IA32_NR_syscalls-1),%rax
 198         ja ia32_badsys
 199         movl %ebx,%edi                  /* reload 1st syscall arg */
 200         movl RCX-ARGOFFSET(%rsp),%esi   /* reload 2nd syscall arg */
 201         movl RDX-ARGOFFSET(%rsp),%edx   /* reload 3rd syscall arg */
 202         movl RSI-ARGOFFSET(%rsp),%ecx   /* reload 4th syscall arg */
 203         movl RDI-ARGOFFSET(%rsp),%r8d   /* reload 5th syscall arg */
 204         .endm
 205
 206         .macro auditsys_exit exit
 207         testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
 208         jnz ia32_ret_from_sys_call
 209         TRACE_IRQS_ON
 210         ENABLE_INTERRUPTS(CLBR_NONE)
 211         movl %eax,%esi          /* second arg, syscall return value */
 212         cmpl $-MAX_ERRNO,%eax   /* is it an error ? */
 213         jbe 1f
 214         movslq %eax, %rsi       /* if error sign extend to 64 bits */
 215 1:      setbe %al               /* 1 if error, 0 if not */
 216         movzbl %al,%edi         /* zero-extend that into %edi */
 217         call __audit_syscall_exit
 218         movq RAX-ARGOFFSET(%rsp),%rax   /* reload syscall return value */
 219         movl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),%edi
 220         DISABLE_INTERRUPTS(CLBR_NONE)
 221         TRACE_IRQS_OFF
 222         testl %edi,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
 223         jz \exit
 224         CLEAR_RREGS -ARGOFFSET
 225         jmp int_with_check
 226         .endm
 227
 228 sysenter_auditsys:
 229         CFI_RESTORE_STATE
 230         auditsys_entry_common
 231         movl %ebp,%r9d                  /* reload 6th syscall arg */
 232         jmp sysenter_dispatch
 233
 234 sysexit_audit:
 235         auditsys_exit sysexit_from_sys_call
 236 #endif
 237
 238 sysenter_tracesys:
 239 #ifdef CONFIG_AUDITSYSCALL
 240         testl   $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
 241         jz      sysenter_auditsys
 242 #endif
 243         SAVE_REST
 244         CLEAR_RREGS
 245         movq    $-ENOSYS,RAX(%rsp)/* ptrace can change this for a bad syscall */
 246         movq    %rsp,%rdi        /* &pt_regs -> arg1 */
 247         call    syscall_trace_enter
 248         LOAD_ARGS32 ARGOFFSET  /* reload args from stack in case ptrace changed it */
 249         RESTORE_REST
 250         cmpq    $(IA32_NR_syscalls-1),%rax
 251         ja      int_ret_from_sys_call /* sysenter_tracesys has set RAX(%rsp) */
 252         jmp     sysenter_do_call
 253         CFI_ENDPROC
 254 ENDPROC(ia32_sysenter_target)
 255
 256 /*
 257  * 32bit SYSCALL instruction entry.
 258  *
 259  * Arguments:
 260  * %eax System call number.
 261  * %ebx Arg1
 262  * %ecx return EIP
 263  * %edx Arg3
 264  * %esi Arg4
 265  * %edi Arg5
 266  * %ebp Arg2    [note: not saved in the stack frame, should not be touched]
 267  * %esp user stack
 268  * 0(%esp) Arg6
 269  *
 270  * Interrupts off.
 271  *
 272  * This is purely a fast path. For anything complicated we use the int 0x80
 273  * path below.  Set up a complete hardware stack frame to share code
 274  * with the int 0x80 path.
 275  */
 276 ENTRY(ia32_cstar_target)
 277         CFI_STARTPROC32 simple
 278         CFI_SIGNAL_FRAME
 279         CFI_DEF_CFA     rsp,KERNEL_STACK_OFFSET
 280         CFI_REGISTER    rip,rcx
 281         /*CFI_REGISTER  rflags,r11*/
 282         SWAPGS_UNSAFE_STACK
 283         movl    %esp,%r8d
 284         CFI_REGISTER    rsp,r8
 285         movq    PER_CPU_VAR(kernel_stack),%rsp
 286         /*
 287          * No need to follow this irqs on/off section: the syscall
 288          * disabled irqs and here we enable it straight after entry:
 289          */
 290         ENABLE_INTERRUPTS(CLBR_NONE)
 291         SAVE_ARGS 8,0,0
 292         movl    %eax,%eax       /* zero extension */
 293         movq    %rax,ORIG_RAX-ARGOFFSET(%rsp)
 294         movq    %rcx,RIP-ARGOFFSET(%rsp)
 295         CFI_REL_OFFSET rip,RIP-ARGOFFSET
 296         movq    %rbp,RCX-ARGOFFSET(%rsp) /* this lies slightly to ptrace */
 297         movl    %ebp,%ecx
 298         movq    $__USER32_CS,CS-ARGOFFSET(%rsp)
 299         movq    $__USER32_DS,SS-ARGOFFSET(%rsp)
 300         movq    %r11,EFLAGS-ARGOFFSET(%rsp)
 301         /*CFI_REL_OFFSET rflags,EFLAGS-ARGOFFSET*/
 302         movq    %r8,RSP-ARGOFFSET(%rsp)
 303         CFI_REL_OFFSET rsp,RSP-ARGOFFSET
 304         /* no need to do an access_ok check here because r8 has been
 305            32bit zero extended */
 306         /* hardware stack frame is complete now */
 307         ASM_STAC
 308 1:      movl    (%r8),%r9d
 309         _ASM_EXTABLE(1b,ia32_badarg)
 310         ASM_CLAC
 311         orl     $TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP-ARGOFFSET)
 312         testl   $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
 313         CFI_REMEMBER_STATE
 314         jnz   cstar_tracesys
 315         cmpq $IA32_NR_syscalls-1,%rax
 316         ja  ia32_badsys
 317 cstar_do_call:
 318         IA32_ARG_FIXUP 1
 319 cstar_dispatch:
 320         call *ia32_sys_call_table(,%rax,8)
 321         movq %rax,RAX-ARGOFFSET(%rsp)
 322         DISABLE_INTERRUPTS(CLBR_NONE)
 323         TRACE_IRQS_OFF
 324         testl $_TIF_ALLWORK_MASK,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
 325         jnz sysretl_audit
 326 sysretl_from_sys_call:
 327         andl $~TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP-ARGOFFSET)
 328         RESTORE_ARGS 0,-ARG_SKIP,0,0,0
 329         movl RIP-ARGOFFSET(%rsp),%ecx
 330         CFI_REGISTER rip,rcx
 331         movl EFLAGS-ARGOFFSET(%rsp),%r11d
 332         /*CFI_REGISTER rflags,r11*/
 333         xorq    %r10,%r10
 334         xorq    %r9,%r9
 335         xorq    %r8,%r8
 336         TRACE_IRQS_ON
 337         movl RSP-ARGOFFSET(%rsp),%esp
 338         CFI_RESTORE rsp
 339         USERGS_SYSRET32
 340
 341 #ifdef CONFIG_AUDITSYSCALL
 342 cstar_auditsys:
 343         CFI_RESTORE_STATE
 344         movl %r9d,R9-ARGOFFSET(%rsp)    /* register to be clobbered by call */
 345         auditsys_entry_common
 346         movl R9-ARGOFFSET(%rsp),%r9d    /* reload 6th syscall arg */
 347         jmp cstar_dispatch
 348
 349 sysretl_audit:
 350         auditsys_exit sysretl_from_sys_call
 351 #endif
 352
 353 cstar_tracesys:
 354 #ifdef CONFIG_AUDITSYSCALL
 355         testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
 356         jz cstar_auditsys
 357 #endif
 358         xchgl %r9d,%ebp
 359         SAVE_REST
 360         CLEAR_RREGS 0, r9
 361         movq $-ENOSYS,RAX(%rsp) /* ptrace can change this for a bad syscall */
 362         movq %rsp,%rdi        /* &pt_regs -> arg1 */
 363         call syscall_trace_enter
 364         LOAD_ARGS32 ARGOFFSET, 1  /* reload args from stack in case ptrace changed it */
 365         RESTORE_REST
 366         xchgl %ebp,%r9d
 367         cmpq $(IA32_NR_syscalls-1),%rax
 368         ja int_ret_from_sys_call /* cstar_tracesys has set RAX(%rsp) */
 369         jmp cstar_do_call
 370 END(ia32_cstar_target)
 371
 372 ia32_badarg:
 373         ASM_CLAC
 374         movq $-EFAULT,%rax
 375         jmp ia32_sysret
 376         CFI_ENDPROC
 377
 378 /*
 379  * Emulated IA32 system calls via int 0x80.
 380  *
 381  * Arguments:
 382  * %eax System call number.
 383  * %ebx Arg1
 384  * %ecx Arg2
 385  * %edx Arg3
 386  * %esi Arg4
 387  * %edi Arg5
 388  * %ebp Arg6    [note: not saved in the stack frame, should not be touched]
 389  *
 390  * Notes:
 391  * Uses the same stack frame as the x86-64 version.
 392  * All registers except %eax must be saved (but ptrace may violate that)
 393  * Arguments are zero extended. For system calls that want sign extension and
 394  * take long arguments a wrapper is needed. Most calls can just be called
 395  * directly.
 396  * Assumes it is only called from user space and entered with interrupts off.
 397  */
 398
 399 ENTRY(ia32_syscall)
 400         CFI_STARTPROC32 simple
 401         CFI_SIGNAL_FRAME
 402         CFI_DEF_CFA     rsp,SS+8-RIP
 403         /*CFI_REL_OFFSET        ss,SS-RIP*/
 404         CFI_REL_OFFSET  rsp,RSP-RIP
 405         /*CFI_REL_OFFSET        rflags,EFLAGS-RIP*/
 406         /*CFI_REL_OFFSET        cs,CS-RIP*/
 407         CFI_REL_OFFSET  rip,RIP-RIP
 408         PARAVIRT_ADJUST_EXCEPTION_FRAME
 409         SWAPGS
 410         /*
 411          * No need to follow this irqs on/off section: the syscall
 412          * disabled irqs and here we enable it straight after entry:
 413          */
 414         ENABLE_INTERRUPTS(CLBR_NONE)
 415         movl %eax,%eax
 416         pushq_cfi %rax
 417         cld
 418         /* note the registers are not zero extended to the sf.
 419            this could be a problem. */
 420         SAVE_ARGS 0,1,0
 421         orl $TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP-ARGOFFSET)
 422         testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
 423         jnz ia32_tracesys
 424         cmpq $(IA32_NR_syscalls-1),%rax
 425         ja ia32_badsys
 426 ia32_do_call:
 427         IA32_ARG_FIXUP
 428         call *ia32_sys_call_table(,%rax,8) # xxx: rip relative
 429 ia32_sysret:
 430         movq %rax,RAX-ARGOFFSET(%rsp)
 431 ia32_ret_from_sys_call:
 432         CLEAR_RREGS -ARGOFFSET
 433         jmp int_ret_from_sys_call
 434
 435 ia32_tracesys:
 436         SAVE_REST
 437         CLEAR_RREGS
 438         movq $-ENOSYS,RAX(%rsp) /* ptrace can change this for a bad syscall */
 439         movq %rsp,%rdi        /* &pt_regs -> arg1 */
 440         call syscall_trace_enter
 441         LOAD_ARGS32 ARGOFFSET  /* reload args from stack in case ptrace changed it */
 442         RESTORE_REST
 443         cmpq $(IA32_NR_syscalls-1),%rax
 444         ja  int_ret_from_sys_call       /* ia32_tracesys has set RAX(%rsp) */
 445         jmp ia32_do_call
 446 END(ia32_syscall)
 447
 448 ia32_badsys:
 449         movq $0,ORIG_RAX-ARGOFFSET(%rsp)
 450         movq $-ENOSYS,%rax
 451         jmp ia32_sysret
 452
 453         CFI_ENDPROC
 454
 455         .macro PTREGSCALL label, func
 456         ALIGN
 457 GLOBAL(\label)
 458         leaq \func(%rip),%rax
 459         jmp  ia32_ptregs_common
 460         .endm
 461
 462         CFI_STARTPROC32
 463
 464         PTREGSCALL stub32_rt_sigreturn, sys32_rt_sigreturn
 465         PTREGSCALL stub32_sigreturn, sys32_sigreturn
 466         PTREGSCALL stub32_execve, compat_sys_execve
 467         PTREGSCALL stub32_fork, sys_fork
 468         PTREGSCALL stub32_vfork, sys_vfork
 469
 470         ALIGN
 471 GLOBAL(stub32_clone)
 472         leaq sys_clone(%rip),%rax
 473         mov     %r8, %rcx
 474         jmp  ia32_ptregs_common
 475
 476         ALIGN
 477 ia32_ptregs_common:
 478         popq %r11
 479         CFI_ENDPROC
 480         CFI_STARTPROC32 simple
 481         CFI_SIGNAL_FRAME
 482         CFI_DEF_CFA     rsp,SS+8-ARGOFFSET
 483         CFI_REL_OFFSET  rax,RAX-ARGOFFSET
 484         CFI_REL_OFFSET  rcx,RCX-ARGOFFSET
 485         CFI_REL_OFFSET  rdx,RDX-ARGOFFSET
 486         CFI_REL_OFFSET  rsi,RSI-ARGOFFSET
 487         CFI_REL_OFFSET  rdi,RDI-ARGOFFSET
 488         CFI_REL_OFFSET  rip,RIP-ARGOFFSET
 489 /*      CFI_REL_OFFSET  cs,CS-ARGOFFSET*/
 490 /*      CFI_REL_OFFSET  rflags,EFLAGS-ARGOFFSET*/
 491         CFI_REL_OFFSET  rsp,RSP-ARGOFFSET
 492 /*      CFI_REL_OFFSET  ss,SS-ARGOFFSET*/
 493         SAVE_REST
 494         call *%rax
 495         RESTORE_REST
 496         jmp  ia32_sysret        /* misbalances the return cache */
 497         CFI_ENDPROC
 498 END(ia32_ptregs_common)