/* * Compatibility mode system call entry point for x86-64. * * Copyright 2000-2002 Andi Kleen, SuSE Labs. */ #include #include #include #include #include #include #include #include #include #include #include #include #include /* Avoid __ASSEMBLER__'ifying just for this. */ #include #define AUDIT_ARCH_I386 (EM_386|__AUDIT_ARCH_LE) #define __AUDIT_ARCH_LE 0x40000000 #ifndef CONFIG_AUDITSYSCALL #define sysexit_audit ia32_ret_from_sys_call #define sysretl_audit ia32_ret_from_sys_call #endif .section .entry.text, "ax" .macro IA32_ARG_FIXUP noebp=0 movl %edi,%r8d .if \noebp .else movl %ebp,%r9d .endif xchg %ecx,%esi movl %ebx,%edi movl %edx,%edx /* zero extension */ .endm /* clobbers %rax */ .macro CLEAR_RREGS _r9=rax xorl %eax,%eax movq %rax,R11(%rsp) movq %rax,R10(%rsp) movq %\_r9,R9(%rsp) movq %rax,R8(%rsp) .endm /* * Reload arg registers from stack in case ptrace changed them. * We don't reload %eax because syscall_trace_enter() returned * the %rax value we should see. Instead, we just truncate that * value to 32 bits again as we did on entry from user mode. * If it's a new value set by user_regset during entry tracing, * this matches the normal truncation of the user-mode value. * If it's -1 to make us punt the syscall, then (u32)-1 is still * an appropriately invalid value. */ .macro LOAD_ARGS32 _r9=0 .if \_r9 movl R9(%rsp),%r9d .endif movl RCX(%rsp),%ecx movl RDX(%rsp),%edx movl RSI(%rsp),%esi movl RDI(%rsp),%edi movl %eax,%eax /* zero extension */ .endm .macro CFI_STARTPROC32 simple CFI_STARTPROC \simple CFI_UNDEFINED r8 CFI_UNDEFINED r9 CFI_UNDEFINED r10 CFI_UNDEFINED r11 CFI_UNDEFINED r12 CFI_UNDEFINED r13 CFI_UNDEFINED r14 CFI_UNDEFINED r15 .endm #ifdef CONFIG_PARAVIRT ENTRY(native_usergs_sysret32) swapgs sysretl ENDPROC(native_usergs_sysret32) ENTRY(native_irq_enable_sysexit) swapgs sti sysexit ENDPROC(native_irq_enable_sysexit) #endif /* * 32bit SYSENTER instruction entry. * * SYSENTER loads ss, rsp, cs, and rip from previously programmed MSRs. * IF and VM in rflags are cleared (IOW: interrupts are off). * SYSENTER does not save anything on the stack, * and does not save old rip (!!!) and rflags. * * Arguments: * eax system call number * ebx arg1 * ecx arg2 * edx arg3 * esi arg4 * edi arg5 * ebp user stack * 0(%ebp) arg6 * * This is purely a fast path. For anything complicated we use the int 0x80 * path below. We set up a complete hardware stack frame to share code * with the int 0x80 path. */ ENTRY(ia32_sysenter_target) CFI_STARTPROC32 simple CFI_SIGNAL_FRAME CFI_DEF_CFA rsp,0 CFI_REGISTER rsp,rbp SWAPGS_UNSAFE_STACK movq PER_CPU_VAR(kernel_stack), %rsp addq $(KERNEL_STACK_OFFSET),%rsp /* * No need to follow this irqs on/off section: the syscall * disabled irqs, here we enable it straight after entry: */ ENABLE_INTERRUPTS(CLBR_NONE) /* Construct iret frame (ss,rsp,rflags,cs,rip) */ movl %ebp,%ebp /* zero extension */ pushq_cfi $__USER32_DS /*CFI_REL_OFFSET ss,0*/ pushq_cfi %rbp CFI_REL_OFFSET rsp,0 pushfq_cfi /*CFI_REL_OFFSET rflags,0*/ movl TI_sysenter_return+THREAD_INFO(%rsp,3*8-KERNEL_STACK_OFFSET),%r10d CFI_REGISTER rip,r10 pushq_cfi $__USER32_CS /*CFI_REL_OFFSET cs,0*/ movl %eax, %eax /* Store thread_info->sysenter_return in rip stack slot */ pushq_cfi %r10 CFI_REL_OFFSET rip,0 /* Store orig_ax */ pushq_cfi %rax /* Construct the rest of "struct pt_regs" */ cld ALLOC_PT_GPREGS_ON_STACK SAVE_C_REGS_EXCEPT_R891011 /* * no need to do an access_ok check here because rbp has been * 32bit zero extended */ ASM_STAC 1: movl (%rbp),%ebp _ASM_EXTABLE(1b,ia32_badarg) ASM_CLAC /* * Sysenter doesn't filter flags, so we need to clear NT * ourselves. To save a few cycles, we can check whether * NT was set instead of doing an unconditional popfq. */ testl $X86_EFLAGS_NT,EFLAGS(%rsp) jnz sysenter_fix_flags sysenter_flags_fixed: orl $TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP) testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,RIP) CFI_REMEMBER_STATE jnz sysenter_tracesys cmpq $(IA32_NR_syscalls-1),%rax ja ia32_badsys sysenter_do_call: IA32_ARG_FIXUP sysenter_dispatch: call *ia32_sys_call_table(,%rax,8) movq %rax,RAX(%rsp) DISABLE_INTERRUPTS(CLBR_NONE) TRACE_IRQS_OFF testl $_TIF_ALLWORK_MASK,TI_flags+THREAD_INFO(%rsp,RIP) jnz sysexit_audit sysexit_from_sys_call: andl $~TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP) /* clear IF, that popfq doesn't enable interrupts early */ andl $~0x200,EFLAGS(%rsp) movl RIP(%rsp),%edx /* User %eip */ CFI_REGISTER rip,rdx RESTORE_RSI_RDI /* pop everything except ss,rsp,rflags slots */ REMOVE_PT_GPREGS_FROM_STACK 3*8 xorq %r8,%r8 xorq %r9,%r9 xorq %r10,%r10 xorq %r11,%r11 popfq_cfi /*CFI_RESTORE rflags*/ popq_cfi %rcx /* User %esp */ CFI_REGISTER rsp,rcx TRACE_IRQS_ON /* * 32bit SYSEXIT restores eip from edx, esp from ecx. * cs and ss are loaded from MSRs. */ ENABLE_INTERRUPTS_SYSEXIT32 CFI_RESTORE_STATE #ifdef CONFIG_AUDITSYSCALL .macro auditsys_entry_common movl %esi,%r8d /* 5th arg: 4th syscall arg */ movl %ecx,%r9d /*swap with edx*/ movl %edx,%ecx /* 4th arg: 3rd syscall arg */ movl %r9d,%edx /* 3rd arg: 2nd syscall arg */ movl %ebx,%esi /* 2nd arg: 1st syscall arg */ movl %eax,%edi /* 1st arg: syscall number */ call __audit_syscall_entry movl RAX(%rsp),%eax /* reload syscall number */ cmpq $(IA32_NR_syscalls-1),%rax ja ia32_badsys movl %ebx,%edi /* reload 1st syscall arg */ movl RCX(%rsp),%esi /* reload 2nd syscall arg */ movl RDX(%rsp),%edx /* reload 3rd syscall arg */ movl RSI(%rsp),%ecx /* reload 4th syscall arg */ movl RDI(%rsp),%r8d /* reload 5th syscall arg */ .endm .macro auditsys_exit exit testl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,RIP) jnz ia32_ret_from_sys_call TRACE_IRQS_ON ENABLE_INTERRUPTS(CLBR_NONE) movl %eax,%esi /* second arg, syscall return value */ cmpl $-MAX_ERRNO,%eax /* is it an error ? */ jbe 1f movslq %eax, %rsi /* if error sign extend to 64 bits */ 1: setbe %al /* 1 if error, 0 if not */ movzbl %al,%edi /* zero-extend that into %edi */ call __audit_syscall_exit movq RAX(%rsp),%rax /* reload syscall return value */ movl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),%edi DISABLE_INTERRUPTS(CLBR_NONE) TRACE_IRQS_OFF testl %edi,TI_flags+THREAD_INFO(%rsp,RIP) jz \exit CLEAR_RREGS jmp int_with_check .endm sysenter_auditsys: auditsys_entry_common movl %ebp,%r9d /* reload 6th syscall arg */ jmp sysenter_dispatch sysexit_audit: auditsys_exit sysexit_from_sys_call #endif sysenter_fix_flags: pushq_cfi $(X86_EFLAGS_IF|X86_EFLAGS_FIXED) popfq_cfi jmp sysenter_flags_fixed sysenter_tracesys: #ifdef CONFIG_AUDITSYSCALL testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,RIP) jz sysenter_auditsys #endif SAVE_EXTRA_REGS CLEAR_RREGS movq $-ENOSYS,RAX(%rsp)/* ptrace can change this for a bad syscall */ movq %rsp,%rdi /* &pt_regs -> arg1 */ call syscall_trace_enter LOAD_ARGS32 /* reload args from stack in case ptrace changed it */ RESTORE_EXTRA_REGS cmpq $(IA32_NR_syscalls-1),%rax ja int_ret_from_sys_call /* sysenter_tracesys has set RAX(%rsp) */ jmp sysenter_do_call CFI_ENDPROC ENDPROC(ia32_sysenter_target) /* * 32bit SYSCALL instruction entry. * * 32bit SYSCALL saves rip to rcx, clears rflags.RF, then saves rflags to r11, * then loads new ss, cs, and rip from previously programmed MSRs. * rflags gets masked by a value from another MSR (so CLD and CLAC * are not needed). SYSCALL does not save anything on the stack * and does not change rsp. * * Note: rflags saving+masking-with-MSR happens only in Long mode * (in legacy 32bit mode, IF, RF and VM bits are cleared and that's it). * Don't get confused: rflags saving+masking depends on Long Mode Active bit * (EFER.LMA=1), NOT on bitness of userspace where SYSCALL executes * or target CS descriptor's L bit (SYSCALL does not read segment descriptors). * * Arguments: * eax system call number * ecx return address * ebx arg1 * ebp arg2 (note: not saved in the stack frame, should not be touched) * edx arg3 * esi arg4 * edi arg5 * esp user stack * 0(%esp) arg6 * * This is purely a fast path. For anything complicated we use the int 0x80 * path below. We set up a complete hardware stack frame to share code * with the int 0x80 path. */ ENTRY(ia32_cstar_target) CFI_STARTPROC32 simple CFI_SIGNAL_FRAME CFI_DEF_CFA rsp,KERNEL_STACK_OFFSET CFI_REGISTER rip,rcx /*CFI_REGISTER rflags,r11*/ SWAPGS_UNSAFE_STACK movl %esp,%r8d CFI_REGISTER rsp,r8 movq PER_CPU_VAR(kernel_stack),%rsp /* * No need to follow this irqs on/off section: the syscall * disabled irqs and here we enable it straight after entry: */ ENABLE_INTERRUPTS(CLBR_NONE) ALLOC_PT_GPREGS_ON_STACK 8 /* +8: space for orig_ax */ SAVE_C_REGS_EXCEPT_RCX_R891011 movl %eax,%eax /* zero extension */ movq %rax,ORIG_RAX(%rsp) movq %rcx,RIP(%rsp) CFI_REL_OFFSET rip,RIP movq %rbp,RCX(%rsp) /* this lies slightly to ptrace */ movl %ebp,%ecx movq $__USER32_CS,CS(%rsp) movq $__USER32_DS,SS(%rsp) movq %r11,EFLAGS(%rsp) /*CFI_REL_OFFSET rflags,EFLAGS*/ movq %r8,RSP(%rsp) CFI_REL_OFFSET rsp,RSP /* iret stack frame is complete now */ /* * no need to do an access_ok check here because r8 has been * 32bit zero extended */ ASM_STAC 1: movl (%r8),%r9d _ASM_EXTABLE(1b,ia32_badarg) ASM_CLAC orl $TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP) testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,RIP) CFI_REMEMBER_STATE jnz cstar_tracesys cmpq $IA32_NR_syscalls-1,%rax ja ia32_badsys cstar_do_call: IA32_ARG_FIXUP 1 cstar_dispatch: call *ia32_sys_call_table(,%rax,8) movq %rax,RAX(%rsp) DISABLE_INTERRUPTS(CLBR_NONE) TRACE_IRQS_OFF testl $_TIF_ALLWORK_MASK,TI_flags+THREAD_INFO(%rsp,RIP) jnz sysretl_audit sysretl_from_sys_call: andl $~TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP) RESTORE_RSI_RDI_RDX movl RIP(%rsp),%ecx CFI_REGISTER rip,rcx movl EFLAGS(%rsp),%r11d /*CFI_REGISTER rflags,r11*/ xorq %r10,%r10 xorq %r9,%r9 xorq %r8,%r8 TRACE_IRQS_ON movl RSP(%rsp),%esp CFI_RESTORE rsp /* * 64bit->32bit SYSRET restores eip from ecx, * eflags from r11 (but RF and VM bits are forced to 0), * cs and ss are loaded from MSRs. * (Note: 32bit->32bit SYSRET is different: since r11 * does not exist, it merely sets eflags.IF=1). */ USERGS_SYSRET32 #ifdef CONFIG_AUDITSYSCALL cstar_auditsys: CFI_RESTORE_STATE movl %r9d,R9(%rsp) /* register to be clobbered by call */ auditsys_entry_common movl R9(%rsp),%r9d /* reload 6th syscall arg */ jmp cstar_dispatch sysretl_audit: auditsys_exit sysretl_from_sys_call #endif cstar_tracesys: #ifdef CONFIG_AUDITSYSCALL testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags+THREAD_INFO(%rsp,RIP) jz cstar_auditsys #endif xchgl %r9d,%ebp SAVE_EXTRA_REGS CLEAR_RREGS r9 movq $-ENOSYS,RAX(%rsp) /* ptrace can change this for a bad syscall */ movq %rsp,%rdi /* &pt_regs -> arg1 */ call syscall_trace_enter LOAD_ARGS32 1 /* reload args from stack in case ptrace changed it */ RESTORE_EXTRA_REGS xchgl %ebp,%r9d cmpq $(IA32_NR_syscalls-1),%rax ja int_ret_from_sys_call /* cstar_tracesys has set RAX(%rsp) */ jmp cstar_do_call END(ia32_cstar_target) ia32_badarg: ASM_CLAC movq $-EFAULT,%rax jmp ia32_sysret CFI_ENDPROC /* * Emulated IA32 system calls via int 0x80. * * Arguments: * eax system call number * ebx arg1 * ecx arg2 * edx arg3 * esi arg4 * edi arg5 * ebp arg6 (note: not saved in the stack frame, should not be touched) * * Notes: * Uses the same stack frame as the x86-64 version. * All registers except eax must be saved (but ptrace may violate that). * Arguments are zero extended. For system calls that want sign extension and * take long arguments a wrapper is needed. Most calls can just be called * directly. * Assumes it is only called from user space and entered with interrupts off. */ ENTRY(ia32_syscall) CFI_STARTPROC32 simple CFI_SIGNAL_FRAME CFI_DEF_CFA rsp,SS+8-RIP /*CFI_REL_OFFSET ss,SS-RIP*/ CFI_REL_OFFSET rsp,RSP-RIP /*CFI_REL_OFFSET rflags,EFLAGS-RIP*/ /*CFI_REL_OFFSET cs,CS-RIP*/ CFI_REL_OFFSET rip,RIP-RIP PARAVIRT_ADJUST_EXCEPTION_FRAME SWAPGS /* * No need to follow this irqs on/off section: the syscall * disabled irqs and here we enable it straight after entry: */ ENABLE_INTERRUPTS(CLBR_NONE) movl %eax,%eax pushq_cfi %rax /* store orig_ax */ cld /* note the registers are not zero extended to the sf. this could be a problem. */ ALLOC_PT_GPREGS_ON_STACK SAVE_C_REGS_EXCEPT_R891011 orl $TS_COMPAT,TI_status+THREAD_INFO(%rsp,RIP) testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,RIP) jnz ia32_tracesys cmpq $(IA32_NR_syscalls-1),%rax ja ia32_badsys ia32_do_call: IA32_ARG_FIXUP call *ia32_sys_call_table(,%rax,8) # xxx: rip relative ia32_sysret: movq %rax,RAX(%rsp) ia32_ret_from_sys_call: CLEAR_RREGS jmp int_ret_from_sys_call ia32_tracesys: SAVE_EXTRA_REGS CLEAR_RREGS movq $-ENOSYS,RAX(%rsp) /* ptrace can change this for a bad syscall */ movq %rsp,%rdi /* &pt_regs -> arg1 */ call syscall_trace_enter LOAD_ARGS32 /* reload args from stack in case ptrace changed it */ RESTORE_EXTRA_REGS cmpq $(IA32_NR_syscalls-1),%rax ja int_ret_from_sys_call /* ia32_tracesys has set RAX(%rsp) */ jmp ia32_do_call END(ia32_syscall) ia32_badsys: movq $0,ORIG_RAX(%rsp) movq $-ENOSYS,%rax jmp ia32_sysret CFI_ENDPROC .macro PTREGSCALL label, func ALIGN GLOBAL(\label) leaq \func(%rip),%rax jmp ia32_ptregs_common .endm CFI_STARTPROC32 PTREGSCALL stub32_rt_sigreturn, sys32_rt_sigreturn PTREGSCALL stub32_sigreturn, sys32_sigreturn PTREGSCALL stub32_execve, compat_sys_execve PTREGSCALL stub32_execveat, compat_sys_execveat PTREGSCALL stub32_fork, sys_fork PTREGSCALL stub32_vfork, sys_vfork ALIGN GLOBAL(stub32_clone) leaq sys_clone(%rip),%rax mov %r8, %rcx jmp ia32_ptregs_common ALIGN ia32_ptregs_common: CFI_ENDPROC CFI_STARTPROC32 simple CFI_SIGNAL_FRAME CFI_DEF_CFA rsp,SS+8 CFI_REL_OFFSET rax,RAX CFI_REL_OFFSET rcx,RCX CFI_REL_OFFSET rdx,RDX CFI_REL_OFFSET rsi,RSI CFI_REL_OFFSET rdi,RDI CFI_REL_OFFSET rip,RIP /* CFI_REL_OFFSET cs,CS*/ /* CFI_REL_OFFSET rflags,EFLAGS*/ CFI_REL_OFFSET rsp,RSP /* CFI_REL_OFFSET ss,SS*/ SAVE_EXTRA_REGS 8 call *%rax RESTORE_EXTRA_REGS 8 ret CFI_ENDPROC END(ia32_ptregs_common)