/* * linux/arch/i386/entry.S * * Copyright (C) 1991, 1992 Linus Torvalds */ /* * entry.S contains the system-call and fault low-level handling routines. * This also contains the timer-interrupt handler, as well as all interrupts * and faults that can result in a task-switch. * * NOTE: This code handles signal-recognition, which happens every time * after a timer-interrupt and after each system call. * * I changed all the .align's to 4 (16 byte alignment), as that's faster * on a 486. * * Stack layout in 'syscall_exit': * ptrace needs to have all regs on the stack. * if the order here is changed, it needs to be * updated in fork.c:copy_process, signal.c:do_signal, * ptrace.c and ptrace.h * * 0(%esp) - %ebx * 4(%esp) - %ecx * 8(%esp) - %edx * C(%esp) - %esi * 10(%esp) - %edi * 14(%esp) - %ebp * 18(%esp) - %eax * 1C(%esp) - %ds * 20(%esp) - %es * 24(%esp) - %fs * 28(%esp) - orig_eax * 2C(%esp) - %eip * 30(%esp) - %cs * 34(%esp) - %eflags * 38(%esp) - %oldesp * 3C(%esp) - %oldss * * "current" is in register %ebx during any slow entries. */ #include #include #include #include #include #include #include #include #include #include #include "irq_vectors.h" /* * We use macros for low-level operations which need to be overridden * for paravirtualization. The following will never clobber any registers: * INTERRUPT_RETURN (aka. "iret") * GET_CR0_INTO_EAX (aka. "movl %cr0, %eax") * ENABLE_INTERRUPTS_SYSEXIT (aka "sti; sysexit"). * * For DISABLE_INTERRUPTS/ENABLE_INTERRUPTS (aka "cli"/"sti"), you must * specify what registers can be overwritten (CLBR_NONE, CLBR_EAX/EDX/ECX/ANY). * Allowing a register to be clobbered can shrink the paravirt replacement * enough to patch inline, increasing performance. */ #define nr_syscalls ((syscall_table_size)/4) CF_MASK = 0x00000001 TF_MASK = 0x00000100 IF_MASK = 0x00000200 DF_MASK = 0x00000400 NT_MASK = 0x00004000 VM_MASK = 0x00020000 #ifdef CONFIG_PREEMPT #define preempt_stop(clobbers) DISABLE_INTERRUPTS(clobbers); TRACE_IRQS_OFF #else #define preempt_stop(clobbers) #define resume_kernel restore_nocheck #endif .macro TRACE_IRQS_IRET #ifdef CONFIG_TRACE_IRQFLAGS testl $IF_MASK,PT_EFLAGS(%esp) # interrupts off? jz 1f TRACE_IRQS_ON 1: #endif .endm #ifdef CONFIG_VM86 #define resume_userspace_sig check_userspace #else #define resume_userspace_sig resume_userspace #endif #define SAVE_ALL \ cld; \ pushl %fs; \ CFI_ADJUST_CFA_OFFSET 4;\ /*CFI_REL_OFFSET fs, 0;*/\ pushl %es; \ CFI_ADJUST_CFA_OFFSET 4;\ /*CFI_REL_OFFSET es, 0;*/\ pushl %ds; \ CFI_ADJUST_CFA_OFFSET 4;\ /*CFI_REL_OFFSET ds, 0;*/\ pushl %eax; \ CFI_ADJUST_CFA_OFFSET 4;\ CFI_REL_OFFSET eax, 0;\ pushl %ebp; \ CFI_ADJUST_CFA_OFFSET 4;\ CFI_REL_OFFSET ebp, 0;\ pushl %edi; \ CFI_ADJUST_CFA_OFFSET 4;\ CFI_REL_OFFSET edi, 0;\ pushl %esi; \ CFI_ADJUST_CFA_OFFSET 4;\ CFI_REL_OFFSET esi, 0;\ pushl %edx; \ CFI_ADJUST_CFA_OFFSET 4;\ CFI_REL_OFFSET edx, 0;\ pushl %ecx; \ CFI_ADJUST_CFA_OFFSET 4;\ CFI_REL_OFFSET ecx, 0;\ pushl %ebx; \ CFI_ADJUST_CFA_OFFSET 4;\ CFI_REL_OFFSET ebx, 0;\ movl $(__USER_DS), %edx; \ movl %edx, %ds; \ movl %edx, %es; \ movl $(__KERNEL_PERCPU), %edx; \ movl %edx, %fs #define RESTORE_INT_REGS \ popl %ebx; \ CFI_ADJUST_CFA_OFFSET -4;\ CFI_RESTORE ebx;\ popl %ecx; \ CFI_ADJUST_CFA_OFFSET -4;\ CFI_RESTORE ecx;\ popl %edx; \ CFI_ADJUST_CFA_OFFSET -4;\ CFI_RESTORE edx;\ popl %esi; \ CFI_ADJUST_CFA_OFFSET -4;\ CFI_RESTORE esi;\ popl %edi; \ CFI_ADJUST_CFA_OFFSET -4;\ CFI_RESTORE edi;\ popl %ebp; \ CFI_ADJUST_CFA_OFFSET -4;\ CFI_RESTORE ebp;\ popl %eax; \ CFI_ADJUST_CFA_OFFSET -4;\ CFI_RESTORE eax #define RESTORE_REGS \ RESTORE_INT_REGS; \ 1: popl %ds; \ CFI_ADJUST_CFA_OFFSET -4;\ /*CFI_RESTORE ds;*/\ 2: popl %es; \ CFI_ADJUST_CFA_OFFSET -4;\ /*CFI_RESTORE es;*/\ 3: popl %fs; \ CFI_ADJUST_CFA_OFFSET -4;\ /*CFI_RESTORE fs;*/\ .pushsection .fixup,"ax"; \ 4: movl $0,(%esp); \ jmp 1b; \ 5: movl $0,(%esp); \ jmp 2b; \ 6: movl $0,(%esp); \ jmp 3b; \ .section __ex_table,"a";\ .align 4; \ .long 1b,4b; \ .long 2b,5b; \ .long 3b,6b; \ .popsection #define RING0_INT_FRAME \ CFI_STARTPROC simple;\ CFI_SIGNAL_FRAME;\ CFI_DEF_CFA esp, 3*4;\ /*CFI_OFFSET cs, -2*4;*/\ CFI_OFFSET eip, -3*4 #define RING0_EC_FRAME \ CFI_STARTPROC simple;\ CFI_SIGNAL_FRAME;\ CFI_DEF_CFA esp, 4*4;\ /*CFI_OFFSET cs, -2*4;*/\ CFI_OFFSET eip, -3*4 #define RING0_PTREGS_FRAME \ CFI_STARTPROC simple;\ CFI_SIGNAL_FRAME;\ CFI_DEF_CFA esp, PT_OLDESP-PT_EBX;\ /*CFI_OFFSET cs, PT_CS-PT_OLDESP;*/\ CFI_OFFSET eip, PT_EIP-PT_OLDESP;\ /*CFI_OFFSET es, PT_ES-PT_OLDESP;*/\ /*CFI_OFFSET ds, PT_DS-PT_OLDESP;*/\ CFI_OFFSET eax, PT_EAX-PT_OLDESP;\ CFI_OFFSET ebp, PT_EBP-PT_OLDESP;\ CFI_OFFSET edi, PT_EDI-PT_OLDESP;\ CFI_OFFSET esi, PT_ESI-PT_OLDESP;\ CFI_OFFSET edx, PT_EDX-PT_OLDESP;\ CFI_OFFSET ecx, PT_ECX-PT_OLDESP;\ CFI_OFFSET ebx, PT_EBX-PT_OLDESP ENTRY(ret_from_fork) CFI_STARTPROC pushl %eax CFI_ADJUST_CFA_OFFSET 4 call schedule_tail GET_THREAD_INFO(%ebp) popl %eax CFI_ADJUST_CFA_OFFSET -4 pushl $0x0202 # Reset kernel eflags CFI_ADJUST_CFA_OFFSET 4 popfl CFI_ADJUST_CFA_OFFSET -4 jmp syscall_exit CFI_ENDPROC END(ret_from_fork) /* * Return to user mode is not as complex as all this looks, * but we want the default path for a system call return to * go as quickly as possible which is why some of this is * less clear than it otherwise should be. */ # userspace resumption stub bypassing syscall exit tracing ALIGN RING0_PTREGS_FRAME ret_from_exception: preempt_stop(CLBR_ANY) ret_from_intr: GET_THREAD_INFO(%ebp) check_userspace: movl PT_EFLAGS(%esp), %eax # mix EFLAGS and CS movb PT_CS(%esp), %al andl $(VM_MASK | SEGMENT_RPL_MASK), %eax cmpl $USER_RPL, %eax jb resume_kernel # not returning to v8086 or userspace ENTRY(resume_userspace) DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt # setting need_resched or sigpending # between sampling and the iret movl TI_flags(%ebp), %ecx andl $_TIF_WORK_MASK, %ecx # is there any work to be done on # int/exception return? jne work_pending jmp restore_all END(ret_from_exception) #ifdef CONFIG_PREEMPT ENTRY(resume_kernel) DISABLE_INTERRUPTS(CLBR_ANY) cmpl $0,TI_preempt_count(%ebp) # non-zero preempt_count ? jnz restore_nocheck need_resched: movl TI_flags(%ebp), %ecx # need_resched set ? testb $_TIF_NEED_RESCHED, %cl jz restore_all testl $IF_MASK,PT_EFLAGS(%esp) # interrupts off (exception path) ? jz restore_all call preempt_schedule_irq jmp need_resched END(resume_kernel) #endif CFI_ENDPROC /* SYSENTER_RETURN points to after the "sysenter" instruction in the vsyscall page. See vsyscall-sysentry.S, which defines the symbol. */ # sysenter call handler stub ENTRY(sysenter_entry) CFI_STARTPROC simple CFI_SIGNAL_FRAME CFI_DEF_CFA esp, 0 CFI_REGISTER esp, ebp movl TSS_sysenter_esp0(%esp),%esp sysenter_past_esp: /* * 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) pushl $(__USER_DS) CFI_ADJUST_CFA_OFFSET 4 /*CFI_REL_OFFSET ss, 0*/ pushl %ebp CFI_ADJUST_CFA_OFFSET 4 CFI_REL_OFFSET esp, 0 pushfl CFI_ADJUST_CFA_OFFSET 4 pushl $(__USER_CS) CFI_ADJUST_CFA_OFFSET 4 /*CFI_REL_OFFSET cs, 0*/ /* * Push current_thread_info()->sysenter_return to the stack. * A tiny bit of offset fixup is necessary - 4*4 means the 4 words * pushed above; +8 corresponds to copy_thread's esp0 setting. */ pushl (TI_sysenter_return-THREAD_SIZE+8+4*4)(%esp) CFI_ADJUST_CFA_OFFSET 4 CFI_REL_OFFSET eip, 0 /* * Load the potential sixth argument from user stack. * Careful about security. */ cmpl $__PAGE_OFFSET-3,%ebp jae syscall_fault 1: movl (%ebp),%ebp .section __ex_table,"a" .align 4 .long 1b,syscall_fault .previous pushl %eax CFI_ADJUST_CFA_OFFSET 4 SAVE_ALL GET_THREAD_INFO(%ebp) /* Note, _TIF_SECCOMP is bit number 8, and so it needs testw and not testb */ testw $(_TIF_SYSCALL_EMU|_TIF_SYSCALL_TRACE|_TIF_SECCOMP|_TIF_SYSCALL_AUDIT),TI_flags(%ebp) jnz syscall_trace_entry cmpl $(nr_syscalls), %eax jae syscall_badsys call *sys_call_table(,%eax,4) movl %eax,PT_EAX(%esp) DISABLE_INTERRUPTS(CLBR_ANY) TRACE_IRQS_OFF movl TI_flags(%ebp), %ecx testw $_TIF_ALLWORK_MASK, %cx jne syscall_exit_work /* if something modifies registers it must also disable sysexit */ movl PT_EIP(%esp), %edx movl PT_OLDESP(%esp), %ecx xorl %ebp,%ebp TRACE_IRQS_ON 1: mov PT_FS(%esp), %fs ENABLE_INTERRUPTS_SYSEXIT CFI_ENDPROC .pushsection .fixup,"ax" 2: movl $0,PT_FS(%esp) jmp 1b .section __ex_table,"a" .align 4 .long 1b,2b .popsection ENDPROC(sysenter_entry) # system call handler stub ENTRY(system_call) RING0_INT_FRAME # can't unwind into user space anyway pushl %eax # save orig_eax CFI_ADJUST_CFA_OFFSET 4 SAVE_ALL GET_THREAD_INFO(%ebp) # system call tracing in operation / emulation /* Note, _TIF_SECCOMP is bit number 8, and so it needs testw and not testb */ testw $(_TIF_SYSCALL_EMU|_TIF_SYSCALL_TRACE|_TIF_SECCOMP|_TIF_SYSCALL_AUDIT),TI_flags(%ebp) jnz syscall_trace_entry cmpl $(nr_syscalls), %eax jae syscall_badsys syscall_call: call *sys_call_table(,%eax,4) movl %eax,PT_EAX(%esp) # store the return value syscall_exit: DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt # setting need_resched or sigpending # between sampling and the iret TRACE_IRQS_OFF testl $TF_MASK,PT_EFLAGS(%esp) # If tracing set singlestep flag on exit jz no_singlestep orl $_TIF_SINGLESTEP,TI_flags(%ebp) no_singlestep: movl TI_flags(%ebp), %ecx testw $_TIF_ALLWORK_MASK, %cx # current->work jne syscall_exit_work restore_all: movl PT_EFLAGS(%esp), %eax # mix EFLAGS, SS and CS # Warning: PT_OLDSS(%esp) contains the wrong/random values if we # are returning to the kernel. # See comments in process.c:copy_thread() for details. movb PT_OLDSS(%esp), %ah movb PT_CS(%esp), %al andl $(VM_MASK | (SEGMENT_TI_MASK << 8) | SEGMENT_RPL_MASK), %eax cmpl $((SEGMENT_LDT << 8) | USER_RPL), %eax CFI_REMEMBER_STATE je ldt_ss # returning to user-space with LDT SS restore_nocheck: TRACE_IRQS_IRET restore_nocheck_notrace: RESTORE_REGS addl $4, %esp # skip orig_eax/error_code CFI_ADJUST_CFA_OFFSET -4 1: INTERRUPT_RETURN .section .fixup,"ax" iret_exc: pushl $0 # no error code pushl $do_iret_error jmp error_code .previous .section __ex_table,"a" .align 4 .long 1b,iret_exc .previous CFI_RESTORE_STATE ldt_ss: larl PT_OLDSS(%esp), %eax jnz restore_nocheck testl $0x00400000, %eax # returning to 32bit stack? jnz restore_nocheck # allright, normal return #ifdef CONFIG_PARAVIRT /* * The kernel can't run on a non-flat stack if paravirt mode * is active. Rather than try to fixup the high bits of * ESP, bypass this code entirely. This may break DOSemu * and/or Wine support in a paravirt VM, although the option * is still available to implement the setting of the high * 16-bits in the INTERRUPT_RETURN paravirt-op. */ cmpl $0, paravirt_ops+PARAVIRT_enabled jne restore_nocheck #endif /* If returning to userspace with 16bit stack, * try to fix the higher word of ESP, as the CPU * won't restore it. * This is an "official" bug of all the x86-compatible * CPUs, which we can try to work around to make * dosemu and wine happy. */ movl PT_OLDESP(%esp), %eax movl %esp, %edx call patch_espfix_desc pushl $__ESPFIX_SS CFI_ADJUST_CFA_OFFSET 4 pushl %eax CFI_ADJUST_CFA_OFFSET 4 DISABLE_INTERRUPTS(CLBR_EAX) TRACE_IRQS_OFF lss (%esp), %esp CFI_ADJUST_CFA_OFFSET -8 jmp restore_nocheck CFI_ENDPROC ENDPROC(system_call) # perform work that needs to be done immediately before resumption ALIGN RING0_PTREGS_FRAME # can't unwind into user space anyway work_pending: testb $_TIF_NEED_RESCHED, %cl jz work_notifysig work_resched: call schedule DISABLE_INTERRUPTS(CLBR_ANY) # make sure we don't miss an interrupt # setting need_resched or sigpending # between sampling and the iret TRACE_IRQS_OFF movl TI_flags(%ebp), %ecx andl $_TIF_WORK_MASK, %ecx # is there any work to be done other # than syscall tracing? jz restore_all testb $_TIF_NEED_RESCHED, %cl jnz work_resched work_notifysig: # deal with pending signals and # notify-resume requests #ifdef CONFIG_VM86 testl $VM_MASK, PT_EFLAGS(%esp) movl %esp, %eax jne work_notifysig_v86 # returning to kernel-space or # vm86-space xorl %edx, %edx call do_notify_resume jmp resume_userspace_sig ALIGN work_notifysig_v86: pushl %ecx # save ti_flags for do_notify_resume CFI_ADJUST_CFA_OFFSET 4 call save_v86_state # %eax contains pt_regs pointer popl %ecx CFI_ADJUST_CFA_OFFSET -4 movl %eax, %esp #else movl %esp, %eax #endif xorl %edx, %edx call do_notify_resume jmp resume_userspace_sig END(work_pending) # perform syscall exit tracing ALIGN syscall_trace_entry: movl $-ENOSYS,PT_EAX(%esp) movl %esp, %eax xorl %edx,%edx call do_syscall_trace cmpl $0, %eax jne resume_userspace # ret != 0 -> running under PTRACE_SYSEMU, # so must skip actual syscall movl PT_ORIG_EAX(%esp), %eax cmpl $(nr_syscalls), %eax jnae syscall_call jmp syscall_exit END(syscall_trace_entry) # perform syscall exit tracing ALIGN syscall_exit_work: testb $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP), %cl jz work_pending TRACE_IRQS_ON ENABLE_INTERRUPTS(CLBR_ANY) # could let do_syscall_trace() call # schedule() instead movl %esp, %eax movl $1, %edx call do_syscall_trace jmp resume_userspace END(syscall_exit_work) CFI_ENDPROC RING0_INT_FRAME # can't unwind into user space anyway syscall_fault: pushl %eax # save orig_eax CFI_ADJUST_CFA_OFFSET 4 SAVE_ALL GET_THREAD_INFO(%ebp) movl $-EFAULT,PT_EAX(%esp) jmp resume_userspace END(syscall_fault) syscall_badsys: movl $-ENOSYS,PT_EAX(%esp) jmp resume_userspace END(syscall_badsys) CFI_ENDPROC #define FIXUP_ESPFIX_STACK \ /* since we are on a wrong stack, we cant make it a C code :( */ \ PER_CPU(gdt_page, %ebx); \ GET_DESC_BASE(GDT_ENTRY_ESPFIX_SS, %ebx, %eax, %ax, %al, %ah); \ addl %esp, %eax; \ pushl $__KERNEL_DS; \ CFI_ADJUST_CFA_OFFSET 4; \ pushl %eax; \ CFI_ADJUST_CFA_OFFSET 4; \ lss (%esp), %esp; \ CFI_ADJUST_CFA_OFFSET -8; #define UNWIND_ESPFIX_STACK \ movl %ss, %eax; \ /* see if on espfix stack */ \ cmpw $__ESPFIX_SS, %ax; \ jne 27f; \ movl $__KERNEL_DS, %eax; \ movl %eax, %ds; \ movl %eax, %es; \ /* switch to normal stack */ \ FIXUP_ESPFIX_STACK; \ 27:; /* * Build the entry stubs and pointer table with * some assembler magic. */ .data ENTRY(interrupt) .text ENTRY(irq_entries_start) RING0_INT_FRAME vector=0 .rept NR_IRQS ALIGN .if vector CFI_ADJUST_CFA_OFFSET -4 .endif 1: pushl $~(vector) CFI_ADJUST_CFA_OFFSET 4 jmp common_interrupt .previous .long 1b .text vector=vector+1 .endr END(irq_entries_start) .previous END(interrupt) .previous /* * the CPU automatically disables interrupts when executing an IRQ vector, * so IRQ-flags tracing has to follow that: */ ALIGN common_interrupt: SAVE_ALL TRACE_IRQS_OFF movl %esp,%eax call do_IRQ jmp ret_from_intr ENDPROC(common_interrupt) CFI_ENDPROC #define BUILD_INTERRUPT(name, nr) \ ENTRY(name) \ RING0_INT_FRAME; \ pushl $~(nr); \ CFI_ADJUST_CFA_OFFSET 4; \ SAVE_ALL; \ TRACE_IRQS_OFF \ movl %esp,%eax; \ call smp_##name; \ jmp ret_from_intr; \ CFI_ENDPROC; \ ENDPROC(name) /* The include is where all of the SMP etc. interrupts come from */ #include "entry_arch.h" KPROBE_ENTRY(page_fault) RING0_EC_FRAME pushl $do_page_fault CFI_ADJUST_CFA_OFFSET 4 ALIGN error_code: /* the function address is in %fs's slot on the stack */ pushl %es CFI_ADJUST_CFA_OFFSET 4 /*CFI_REL_OFFSET es, 0*/ pushl %ds CFI_ADJUST_CFA_OFFSET 4 /*CFI_REL_OFFSET ds, 0*/ pushl %eax CFI_ADJUST_CFA_OFFSET 4 CFI_REL_OFFSET eax, 0 pushl %ebp CFI_ADJUST_CFA_OFFSET 4 CFI_REL_OFFSET ebp, 0 pushl %edi CFI_ADJUST_CFA_OFFSET 4 CFI_REL_OFFSET edi, 0 pushl %esi CFI_ADJUST_CFA_OFFSET 4 CFI_REL_OFFSET esi, 0 pushl %edx CFI_ADJUST_CFA_OFFSET 4 CFI_REL_OFFSET edx, 0 pushl %ecx CFI_ADJUST_CFA_OFFSET 4 CFI_REL_OFFSET ecx, 0 pushl %ebx CFI_ADJUST_CFA_OFFSET 4 CFI_REL_OFFSET ebx, 0 cld pushl %fs CFI_ADJUST_CFA_OFFSET 4 /*CFI_REL_OFFSET fs, 0*/ movl $(__KERNEL_PERCPU), %ecx movl %ecx, %fs UNWIND_ESPFIX_STACK popl %ecx CFI_ADJUST_CFA_OFFSET -4 /*CFI_REGISTER es, ecx*/ movl PT_FS(%esp), %edi # get the function address movl PT_ORIG_EAX(%esp), %edx # get the error code movl $-1, PT_ORIG_EAX(%esp) # no syscall to restart mov %ecx, PT_FS(%esp) /*CFI_REL_OFFSET fs, ES*/ movl $(__USER_DS), %ecx movl %ecx, %ds movl %ecx, %es movl %esp,%eax # pt_regs pointer call *%edi jmp ret_from_exception CFI_ENDPROC KPROBE_END(page_fault) ENTRY(coprocessor_error) RING0_INT_FRAME pushl $0 CFI_ADJUST_CFA_OFFSET 4 pushl $do_coprocessor_error CFI_ADJUST_CFA_OFFSET 4 jmp error_code CFI_ENDPROC END(coprocessor_error) ENTRY(simd_coprocessor_error) RING0_INT_FRAME pushl $0 CFI_ADJUST_CFA_OFFSET 4 pushl $do_simd_coprocessor_error CFI_ADJUST_CFA_OFFSET 4 jmp error_code CFI_ENDPROC END(simd_coprocessor_error) ENTRY(device_not_available) RING0_INT_FRAME pushl $-1 # mark this as an int CFI_ADJUST_CFA_OFFSET 4 SAVE_ALL GET_CR0_INTO_EAX testl $0x4, %eax # EM (math emulation bit) jne device_not_available_emulate preempt_stop(CLBR_ANY) call math_state_restore jmp ret_from_exception device_not_available_emulate: pushl $0 # temporary storage for ORIG_EIP CFI_ADJUST_CFA_OFFSET 4 call math_emulate addl $4, %esp CFI_ADJUST_CFA_OFFSET -4 jmp ret_from_exception CFI_ENDPROC END(device_not_available) /* * Debug traps and NMI can happen at the one SYSENTER instruction * that sets up the real kernel stack. Check here, since we can't * allow the wrong stack to be used. * * "TSS_sysenter_esp0+12" is because the NMI/debug handler will have * already pushed 3 words if it hits on the sysenter instruction: * eflags, cs and eip. * * We just load the right stack, and push the three (known) values * by hand onto the new stack - while updating the return eip past * the instruction that would have done it for sysenter. */ #define FIX_STACK(offset, ok, label) \ cmpw $__KERNEL_CS,4(%esp); \ jne ok; \ label: \ movl TSS_sysenter_esp0+offset(%esp),%esp; \ CFI_DEF_CFA esp, 0; \ CFI_UNDEFINED eip; \ pushfl; \ CFI_ADJUST_CFA_OFFSET 4; \ pushl $__KERNEL_CS; \ CFI_ADJUST_CFA_OFFSET 4; \ pushl $sysenter_past_esp; \ CFI_ADJUST_CFA_OFFSET 4; \ CFI_REL_OFFSET eip, 0 KPROBE_ENTRY(debug) RING0_INT_FRAME cmpl $sysenter_entry,(%esp) jne debug_stack_correct FIX_STACK(12, debug_stack_correct, debug_esp_fix_insn) debug_stack_correct: pushl $-1 # mark this as an int CFI_ADJUST_CFA_OFFSET 4 SAVE_ALL xorl %edx,%edx # error code 0 movl %esp,%eax # pt_regs pointer call do_debug jmp ret_from_exception CFI_ENDPROC KPROBE_END(debug) /* * NMI is doubly nasty. It can happen _while_ we're handling * a debug fault, and the debug fault hasn't yet been able to * clear up the stack. So we first check whether we got an * NMI on the sysenter entry path, but after that we need to * check whether we got an NMI on the debug path where the debug * fault happened on the sysenter path. */ KPROBE_ENTRY(nmi) RING0_INT_FRAME pushl %eax CFI_ADJUST_CFA_OFFSET 4 movl %ss, %eax cmpw $__ESPFIX_SS, %ax popl %eax CFI_ADJUST_CFA_OFFSET -4 je nmi_espfix_stack cmpl $sysenter_entry,(%esp) je nmi_stack_fixup pushl %eax CFI_ADJUST_CFA_OFFSET 4 movl %esp,%eax /* Do not access memory above the end of our stack page, * it might not exist. */ andl $(THREAD_SIZE-1),%eax cmpl $(THREAD_SIZE-20),%eax popl %eax CFI_ADJUST_CFA_OFFSET -4 jae nmi_stack_correct cmpl $sysenter_entry,12(%esp) je nmi_debug_stack_check nmi_stack_correct: /* We have a RING0_INT_FRAME here */ pushl %eax CFI_ADJUST_CFA_OFFSET 4 SAVE_ALL xorl %edx,%edx # zero error code movl %esp,%eax # pt_regs pointer call do_nmi jmp restore_nocheck_notrace CFI_ENDPROC nmi_stack_fixup: RING0_INT_FRAME FIX_STACK(12,nmi_stack_correct, 1) jmp nmi_stack_correct nmi_debug_stack_check: /* We have a RING0_INT_FRAME here */ cmpw $__KERNEL_CS,16(%esp) jne nmi_stack_correct cmpl $debug,(%esp) jb nmi_stack_correct cmpl $debug_esp_fix_insn,(%esp) ja nmi_stack_correct FIX_STACK(24,nmi_stack_correct, 1) jmp nmi_stack_correct nmi_espfix_stack: /* We have a RING0_INT_FRAME here. * * create the pointer to lss back */ pushl %ss CFI_ADJUST_CFA_OFFSET 4 pushl %esp CFI_ADJUST_CFA_OFFSET 4 addw $4, (%esp) /* copy the iret frame of 12 bytes */ .rept 3 pushl 16(%esp) CFI_ADJUST_CFA_OFFSET 4 .endr pushl %eax CFI_ADJUST_CFA_OFFSET 4 SAVE_ALL FIXUP_ESPFIX_STACK # %eax == %esp xorl %edx,%edx # zero error code call do_nmi RESTORE_REGS lss 12+4(%esp), %esp # back to espfix stack CFI_ADJUST_CFA_OFFSET -24 1: INTERRUPT_RETURN CFI_ENDPROC .section __ex_table,"a" .align 4 .long 1b,iret_exc .previous KPROBE_END(nmi) #ifdef CONFIG_PARAVIRT ENTRY(native_iret) 1: iret .section __ex_table,"a" .align 4 .long 1b,iret_exc .previous END(native_iret) ENTRY(native_irq_enable_sysexit) sti sysexit END(native_irq_enable_sysexit) #endif KPROBE_ENTRY(int3) RING0_INT_FRAME pushl $-1 # mark this as an int CFI_ADJUST_CFA_OFFSET 4 SAVE_ALL xorl %edx,%edx # zero error code movl %esp,%eax # pt_regs pointer call do_int3 jmp ret_from_exception CFI_ENDPROC KPROBE_END(int3) ENTRY(overflow) RING0_INT_FRAME pushl $0 CFI_ADJUST_CFA_OFFSET 4 pushl $do_overflow CFI_ADJUST_CFA_OFFSET 4 jmp error_code CFI_ENDPROC END(overflow) ENTRY(bounds) RING0_INT_FRAME pushl $0 CFI_ADJUST_CFA_OFFSET 4 pushl $do_bounds CFI_ADJUST_CFA_OFFSET 4 jmp error_code CFI_ENDPROC END(bounds) ENTRY(invalid_op) RING0_INT_FRAME pushl $0 CFI_ADJUST_CFA_OFFSET 4 pushl $do_invalid_op CFI_ADJUST_CFA_OFFSET 4 jmp error_code CFI_ENDPROC END(invalid_op) ENTRY(coprocessor_segment_overrun) RING0_INT_FRAME pushl $0 CFI_ADJUST_CFA_OFFSET 4 pushl $do_coprocessor_segment_overrun CFI_ADJUST_CFA_OFFSET 4 jmp error_code CFI_ENDPROC END(coprocessor_segment_overrun) ENTRY(invalid_TSS) RING0_EC_FRAME pushl $do_invalid_TSS CFI_ADJUST_CFA_OFFSET 4 jmp error_code CFI_ENDPROC END(invalid_TSS) ENTRY(segment_not_present) RING0_EC_FRAME pushl $do_segment_not_present CFI_ADJUST_CFA_OFFSET 4 jmp error_code CFI_ENDPROC END(segment_not_present) ENTRY(stack_segment) RING0_EC_FRAME pushl $do_stack_segment CFI_ADJUST_CFA_OFFSET 4 jmp error_code CFI_ENDPROC END(stack_segment) KPROBE_ENTRY(general_protection) RING0_EC_FRAME pushl $do_general_protection CFI_ADJUST_CFA_OFFSET 4 jmp error_code CFI_ENDPROC KPROBE_END(general_protection) ENTRY(alignment_check) RING0_EC_FRAME pushl $do_alignment_check CFI_ADJUST_CFA_OFFSET 4 jmp error_code CFI_ENDPROC END(alignment_check) ENTRY(divide_error) RING0_INT_FRAME pushl $0 # no error code CFI_ADJUST_CFA_OFFSET 4 pushl $do_divide_error CFI_ADJUST_CFA_OFFSET 4 jmp error_code CFI_ENDPROC END(divide_error) #ifdef CONFIG_X86_MCE ENTRY(machine_check) RING0_INT_FRAME pushl $0 CFI_ADJUST_CFA_OFFSET 4 pushl machine_check_vector CFI_ADJUST_CFA_OFFSET 4 jmp error_code CFI_ENDPROC END(machine_check) #endif ENTRY(spurious_interrupt_bug) RING0_INT_FRAME pushl $0 CFI_ADJUST_CFA_OFFSET 4 pushl $do_spurious_interrupt_bug CFI_ADJUST_CFA_OFFSET 4 jmp error_code CFI_ENDPROC END(spurious_interrupt_bug) ENTRY(kernel_thread_helper) pushl $0 # fake return address for unwinder CFI_STARTPROC movl %edx,%eax push %edx CFI_ADJUST_CFA_OFFSET 4 call *%ebx push %eax CFI_ADJUST_CFA_OFFSET 4 call do_exit CFI_ENDPROC ENDPROC(kernel_thread_helper) #ifdef CONFIG_XEN ENTRY(xen_hypervisor_callback) CFI_STARTPROC pushl $0 CFI_ADJUST_CFA_OFFSET 4 SAVE_ALL TRACE_IRQS_OFF /* Check to see if we got the event in the critical region in xen_iret_direct, after we've reenabled events and checked for pending events. This simulates iret instruction's behaviour where it delivers a pending interrupt when enabling interrupts. */ movl PT_EIP(%esp),%eax cmpl $xen_iret_start_crit,%eax jb 1f cmpl $xen_iret_end_crit,%eax jae 1f call xen_iret_crit_fixup 1: mov %esp, %eax call xen_evtchn_do_upcall jmp ret_from_intr CFI_ENDPROC ENDPROC(xen_hypervisor_callback) # Hypervisor uses this for application faults while it executes. # We get here for two reasons: # 1. Fault while reloading DS, ES, FS or GS # 2. Fault while executing IRET # Category 1 we fix up by reattempting the load, and zeroing the segment # register if the load fails. # Category 2 we fix up by jumping to do_iret_error. We cannot use the # normal Linux return path in this case because if we use the IRET hypercall # to pop the stack frame we end up in an infinite loop of failsafe callbacks. # We distinguish between categories by maintaining a status value in EAX. ENTRY(xen_failsafe_callback) CFI_STARTPROC pushl %eax CFI_ADJUST_CFA_OFFSET 4 movl $1,%eax 1: mov 4(%esp),%ds 2: mov 8(%esp),%es 3: mov 12(%esp),%fs 4: mov 16(%esp),%gs testl %eax,%eax popl %eax CFI_ADJUST_CFA_OFFSET -4 lea 16(%esp),%esp CFI_ADJUST_CFA_OFFSET -16 jz 5f addl $16,%esp jmp iret_exc # EAX != 0 => Category 2 (Bad IRET) 5: pushl $0 # EAX == 0 => Category 1 (Bad segment) CFI_ADJUST_CFA_OFFSET 4 SAVE_ALL jmp ret_from_exception CFI_ENDPROC .section .fixup,"ax" 6: xorl %eax,%eax movl %eax,4(%esp) jmp 1b 7: xorl %eax,%eax movl %eax,8(%esp) jmp 2b 8: xorl %eax,%eax movl %eax,12(%esp) jmp 3b 9: xorl %eax,%eax movl %eax,16(%esp) jmp 4b .previous .section __ex_table,"a" .align 4 .long 1b,6b .long 2b,7b .long 3b,8b .long 4b,9b .previous ENDPROC(xen_failsafe_callback) #endif /* CONFIG_XEN */ .section .rodata,"a" #include "syscall_table_32.S" syscall_table_size=(.-sys_call_table)