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
 155         /*
 156          * Sysenter doesn't filter flags, so we need to clear NT
 157          * ourselves.  To save a few cycles, we can check whether
 158          * NT was set instead of doing an unconditional popfq.
 159          */
 160         testl $X86_EFLAGS_NT,EFLAGS-ARGOFFSET(%rsp)
 161         jnz sysenter_fix_flags
 162 sysenter_flags_fixed:
 163
 164         orl     $TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP-ARGOFFSET)
 165         testl   $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
 166         CFI_REMEMBER_STATE
 167         jnz  sysenter_tracesys
 168         cmpq    $(IA32_NR_syscalls-1),%rax
 169         ja      ia32_badsys
 170 sysenter_do_call:
 171         IA32_ARG_FIXUP
 172 sysenter_dispatch:
 173         call    *ia32_sys_call_table(,%rax,8)
 174         movq    %rax,RAX-ARGOFFSET(%rsp)
 175         DISABLE_INTERRUPTS(CLBR_NONE)
 176         TRACE_IRQS_OFF
 177         testl   $_TIF_ALLWORK_MASK,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
 178         jnz     sysexit_audit
 179 sysexit_from_sys_call:
 180         andl    $~TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP-ARGOFFSET)
 181         /* clear IF, that popfq doesn't enable interrupts early */
 182         andl    $~0x200,EFLAGS-ARGOFFSET(%rsp)
 183         movl    RIP-ARGOFFSET(%rsp),%edx                /* User %eip */
 184         CFI_REGISTER rip,rdx
 185         RESTORE_ARGS 0,24,0,0,0,0
 186         xorq    %r8,%r8
 187         xorq    %r9,%r9
 188         xorq    %r10,%r10
 189         xorq    %r11,%r11
 190         popfq_cfi
 191         /*CFI_RESTORE rflags*/
 192         popq_cfi %rcx                           /* User %esp */
 193         CFI_REGISTER rsp,rcx
 194         TRACE_IRQS_ON
 195         ENABLE_INTERRUPTS_SYSEXIT32
 196
 197         CFI_RESTORE_STATE
 198
 199 #ifdef CONFIG_AUDITSYSCALL
 200         .macro auditsys_entry_common
 201         movl %esi,%r8d                  /* 5th arg: 4th syscall arg */
 202         movl %ecx,%r9d                  /*swap with edx*/
 203         movl %edx,%ecx                  /* 4th arg: 3rd syscall arg */
 204         movl %r9d,%edx                  /* 3rd arg: 2nd syscall arg */
 205         movl %ebx,%esi                  /* 2nd arg: 1st syscall arg */
 206         movl %eax,%edi                  /* 1st arg: syscall number */
 207         call __audit_syscall_entry
 208         movl RAX-ARGOFFSET(%rsp),%eax   /* reload syscall number */
 209         cmpq $(IA32_NR_syscalls-1),%rax
 210         ja ia32_badsys
 211         movl %ebx,%edi                  /* reload 1st syscall arg */
 212         movl RCX-ARGOFFSET(%rsp),%esi   /* reload 2nd syscall arg */
 213         movl RDX-ARGOFFSET(%rsp),%edx   /* reload 3rd syscall arg */
 214         movl RSI-ARGOFFSET(%rsp),%ecx   /* reload 4th syscall arg */
 215         movl RDI-ARGOFFSET(%rsp),%r8d   /* reload 5th syscall arg */
 216         .endm
 217
 218         .macro auditsys_exit exit
 219         testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
 220         jnz ia32_ret_from_sys_call
 221         TRACE_IRQS_ON
 222         ENABLE_INTERRUPTS(CLBR_NONE)
 223         movl %eax,%esi          /* second arg, syscall return value */
 224         cmpl $-MAX_ERRNO,%eax   /* is it an error ? */
 225         jbe 1f
 226         movslq %eax, %rsi       /* if error sign extend to 64 bits */
 227 1:      setbe %al               /* 1 if error, 0 if not */
 228         movzbl %al,%edi         /* zero-extend that into %edi */
 229         call __audit_syscall_exit
 230         movq RAX-ARGOFFSET(%rsp),%rax   /* reload syscall return value */
 231         movl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),%edi
 232         DISABLE_INTERRUPTS(CLBR_NONE)
 233         TRACE_IRQS_OFF
 234         testl %edi,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
 235         jz \exit
 236         CLEAR_RREGS -ARGOFFSET
 237         jmp int_with_check
 238         .endm
 239
 240 sysenter_auditsys:
 241         auditsys_entry_common
 242         movl %ebp,%r9d                  /* reload 6th syscall arg */
 243         jmp sysenter_dispatch
 244
 245 sysexit_audit:
 246         auditsys_exit sysexit_from_sys_call
 247 #endif
 248
 249 sysenter_fix_flags:
 250         pushq_cfi $(X86_EFLAGS_IF|X86_EFLAGS_FIXED)
 251         popfq_cfi
 252         jmp sysenter_flags_fixed
 253
 254 sysenter_tracesys:
 255 #ifdef CONFIG_AUDITSYSCALL
 256         testl   $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
 257         jz      sysenter_auditsys
 258 #endif
 259         SAVE_REST
 260         CLEAR_RREGS
 261         movq    $-ENOSYS,RAX(%rsp)/* ptrace can change this for a bad syscall */
 262         movq    %rsp,%rdi        /* &pt_regs -> arg1 */
 263         call    syscall_trace_enter
 264         LOAD_ARGS32 ARGOFFSET  /* reload args from stack in case ptrace changed it */
 265         RESTORE_REST
 266         cmpq    $(IA32_NR_syscalls-1),%rax
 267         ja      int_ret_from_sys_call /* sysenter_tracesys has set RAX(%rsp) */
 268         jmp     sysenter_do_call
 269         CFI_ENDPROC
 270 ENDPROC(ia32_sysenter_target)
 271
 272 /*
 273  * 32bit SYSCALL instruction entry.
 274  *
 275  * Arguments:
 276  * %eax System call number.
 277  * %ebx Arg1
 278  * %ecx return EIP
 279  * %edx Arg3
 280  * %esi Arg4
 281  * %edi Arg5
 282  * %ebp Arg2    [note: not saved in the stack frame, should not be touched]
 283  * %esp user stack
 284  * 0(%esp) Arg6
 285  *
 286  * Interrupts off.
 287  *
 288  * This is purely a fast path. For anything complicated we use the int 0x80
 289  * path below.  Set up a complete hardware stack frame to share code
 290  * with the int 0x80 path.
 291  */
 292 ENTRY(ia32_cstar_target)
 293         CFI_STARTPROC32 simple
 294         CFI_SIGNAL_FRAME
 295         CFI_DEF_CFA     rsp,KERNEL_STACK_OFFSET
 296         CFI_REGISTER    rip,rcx
 297         /*CFI_REGISTER  rflags,r11*/
 298         SWAPGS_UNSAFE_STACK
 299         movl    %esp,%r8d
 300         CFI_REGISTER    rsp,r8
 301         movq    PER_CPU_VAR(kernel_stack),%rsp
 302         /*
 303          * No need to follow this irqs on/off section: the syscall
 304          * disabled irqs and here we enable it straight after entry:
 305          */
 306         ENABLE_INTERRUPTS(CLBR_NONE)
 307         SAVE_ARGS 8,0,0
 308         movl    %eax,%eax       /* zero extension */
 309         movq    %rax,ORIG_RAX-ARGOFFSET(%rsp)
 310         movq    %rcx,RIP-ARGOFFSET(%rsp)
 311         CFI_REL_OFFSET rip,RIP-ARGOFFSET
 312         movq    %rbp,RCX-ARGOFFSET(%rsp) /* this lies slightly to ptrace */
 313         movl    %ebp,%ecx
 314         movq    $__USER32_CS,CS-ARGOFFSET(%rsp)
 315         movq    $__USER32_DS,SS-ARGOFFSET(%rsp)
 316         movq    %r11,EFLAGS-ARGOFFSET(%rsp)
 317         /*CFI_REL_OFFSET rflags,EFLAGS-ARGOFFSET*/
 318         movq    %r8,RSP-ARGOFFSET(%rsp)
 319         CFI_REL_OFFSET rsp,RSP-ARGOFFSET
 320         /* no need to do an access_ok check here because r8 has been
 321            32bit zero extended */
 322         /* hardware stack frame is complete now */
 323         ASM_STAC
 324 1:      movl    (%r8),%r9d
 325         _ASM_EXTABLE(1b,ia32_badarg)
 326         ASM_CLAC
 327         orl     $TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP-ARGOFFSET)
 328         testl   $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
 329         CFI_REMEMBER_STATE
 330         jnz   cstar_tracesys
 331         cmpq $IA32_NR_syscalls-1,%rax
 332         ja  ia32_badsys
 333 cstar_do_call:
 334         IA32_ARG_FIXUP 1
 335 cstar_dispatch:
 336         call *ia32_sys_call_table(,%rax,8)
 337         movq %rax,RAX-ARGOFFSET(%rsp)
 338         DISABLE_INTERRUPTS(CLBR_NONE)
 339         TRACE_IRQS_OFF
 340         testl $_TIF_ALLWORK_MASK,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
 341         jnz sysretl_audit
 342 sysretl_from_sys_call:
 343         andl $~TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP-ARGOFFSET)
 344         RESTORE_ARGS 0,-ARG_SKIP,0,0,0
 345         movl RIP-ARGOFFSET(%rsp),%ecx
 346         CFI_REGISTER rip,rcx
 347         movl EFLAGS-ARGOFFSET(%rsp),%r11d
 348         /*CFI_REGISTER rflags,r11*/
 349         xorq    %r10,%r10
 350         xorq    %r9,%r9
 351         xorq    %r8,%r8
 352         TRACE_IRQS_ON
 353         movl RSP-ARGOFFSET(%rsp),%esp
 354         CFI_RESTORE rsp
 355         USERGS_SYSRET32
 356
 357 #ifdef CONFIG_AUDITSYSCALL
 358 cstar_auditsys:
 359         CFI_RESTORE_STATE
 360         movl %r9d,R9-ARGOFFSET(%rsp)    /* register to be clobbered by call */
 361         auditsys_entry_common
 362         movl R9-ARGOFFSET(%rsp),%r9d    /* reload 6th syscall arg */
 363         jmp cstar_dispatch
 364
 365 sysretl_audit:
 366         auditsys_exit sysretl_from_sys_call
 367 #endif
 368
 369 cstar_tracesys:
 370 #ifdef CONFIG_AUDITSYSCALL
 371         testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
 372         jz cstar_auditsys
 373 #endif
 374         xchgl %r9d,%ebp
 375         SAVE_REST
 376         CLEAR_RREGS 0, r9
 377         movq $-ENOSYS,RAX(%rsp) /* ptrace can change this for a bad syscall */
 378         movq %rsp,%rdi        /* &pt_regs -> arg1 */
 379         call syscall_trace_enter
 380         LOAD_ARGS32 ARGOFFSET, 1  /* reload args from stack in case ptrace changed it */
 381         RESTORE_REST
 382         xchgl %ebp,%r9d
 383         cmpq $(IA32_NR_syscalls-1),%rax
 384         ja int_ret_from_sys_call /* cstar_tracesys has set RAX(%rsp) */
 385         jmp cstar_do_call
 386 END(ia32_cstar_target)
 387
 388 ia32_badarg:
 389         ASM_CLAC
 390         movq $-EFAULT,%rax
 391         jmp ia32_sysret
 392         CFI_ENDPROC
 393
 394 /*
 395  * Emulated IA32 system calls via int 0x80.
 396  *
 397  * Arguments:
 398  * %eax System call number.
 399  * %ebx Arg1
 400  * %ecx Arg2
 401  * %edx Arg3
 402  * %esi Arg4
 403  * %edi Arg5
 404  * %ebp Arg6    [note: not saved in the stack frame, should not be touched]
 405  *
 406  * Notes:
 407  * Uses the same stack frame as the x86-64 version.
 408  * All registers except %eax must be saved (but ptrace may violate that)
 409  * Arguments are zero extended. For system calls that want sign extension and
 410  * take long arguments a wrapper is needed. Most calls can just be called
 411  * directly.
 412  * Assumes it is only called from user space and entered with interrupts off.
 413  */
 414
 415 ENTRY(ia32_syscall)
 416         CFI_STARTPROC32 simple
 417         CFI_SIGNAL_FRAME
 418         CFI_DEF_CFA     rsp,SS+8-RIP
 419         /*CFI_REL_OFFSET        ss,SS-RIP*/
 420         CFI_REL_OFFSET  rsp,RSP-RIP
 421         /*CFI_REL_OFFSET        rflags,EFLAGS-RIP*/
 422         /*CFI_REL_OFFSET        cs,CS-RIP*/
 423         CFI_REL_OFFSET  rip,RIP-RIP
 424         PARAVIRT_ADJUST_EXCEPTION_FRAME
 425         SWAPGS
 426         /*
 427          * No need to follow this irqs on/off section: the syscall
 428          * disabled irqs and here we enable it straight after entry:
 429          */
 430         ENABLE_INTERRUPTS(CLBR_NONE)
 431         movl %eax,%eax
 432         pushq_cfi %rax
 433         cld
 434         /* note the registers are not zero extended to the sf.
 435            this could be a problem. */
 436         SAVE_ARGS 0,1,0
 437         orl $TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP-ARGOFFSET)
 438         testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET)
 439         jnz ia32_tracesys
 440         cmpq $(IA32_NR_syscalls-1),%rax
 441         ja ia32_badsys
 442 ia32_do_call:
 443         IA32_ARG_FIXUP
 444         call *ia32_sys_call_table(,%rax,8) # xxx: rip relative
 445 ia32_sysret:
 446         movq %rax,RAX-ARGOFFSET(%rsp)
 447 ia32_ret_from_sys_call:
 448         CLEAR_RREGS -ARGOFFSET
 449         jmp int_ret_from_sys_call
 450
 451 ia32_tracesys:
 452         SAVE_REST
 453         CLEAR_RREGS
 454         movq $-ENOSYS,RAX(%rsp) /* ptrace can change this for a bad syscall */
 455         movq %rsp,%rdi        /* &pt_regs -> arg1 */
 456         call syscall_trace_enter
 457         LOAD_ARGS32 ARGOFFSET  /* reload args from stack in case ptrace changed it */
 458         RESTORE_REST
 459         cmpq $(IA32_NR_syscalls-1),%rax
 460         ja  int_ret_from_sys_call       /* ia32_tracesys has set RAX(%rsp) */
 461         jmp ia32_do_call
 462 END(ia32_syscall)
 463
 464 ia32_badsys:
 465         movq $0,ORIG_RAX-ARGOFFSET(%rsp)
 466         movq $-ENOSYS,%rax
 467         jmp ia32_sysret
 468
 469         CFI_ENDPROC
 470
 471         .macro PTREGSCALL label, func
 472         ALIGN
 473 GLOBAL(\label)
 474         leaq \func(%rip),%rax
 475         jmp  ia32_ptregs_common
 476         .endm
 477
 478         CFI_STARTPROC32
 479
 480         PTREGSCALL stub32_rt_sigreturn, sys32_rt_sigreturn
 481         PTREGSCALL stub32_sigreturn, sys32_sigreturn
 482         PTREGSCALL stub32_execve, compat_sys_execve
 483         PTREGSCALL stub32_execveat, compat_sys_execveat
 484         PTREGSCALL stub32_fork, sys_fork
 485         PTREGSCALL stub32_vfork, sys_vfork
 486
 487         ALIGN
 488 GLOBAL(stub32_clone)
 489         leaq sys_clone(%rip),%rax
 490         mov     %r8, %rcx
 491         jmp  ia32_ptregs_common
 492
 493         ALIGN
 494 ia32_ptregs_common:
 495         popq %r11
 496         CFI_ENDPROC
 497         CFI_STARTPROC32 simple
 498         CFI_SIGNAL_FRAME
 499         CFI_DEF_CFA     rsp,SS+8-ARGOFFSET
 500         CFI_REL_OFFSET  rax,RAX-ARGOFFSET
 501         CFI_REL_OFFSET  rcx,RCX-ARGOFFSET
 502         CFI_REL_OFFSET  rdx,RDX-ARGOFFSET
 503         CFI_REL_OFFSET  rsi,RSI-ARGOFFSET
 504         CFI_REL_OFFSET  rdi,RDI-ARGOFFSET
 505         CFI_REL_OFFSET  rip,RIP-ARGOFFSET
 506 /*      CFI_REL_OFFSET  cs,CS-ARGOFFSET*/
 507 /*      CFI_REL_OFFSET  rflags,EFLAGS-ARGOFFSET*/
 508         CFI_REL_OFFSET  rsp,RSP-ARGOFFSET
 509 /*      CFI_REL_OFFSET  ss,SS-ARGOFFSET*/
 510         SAVE_REST
 511         call *%rax
 512         RESTORE_REST
 513         jmp  ia32_sysret        /* misbalances the return cache */
 514         CFI_ENDPROC
 515 END(ia32_ptregs_common)