| /* |
| * linux/arch/x86_64/entry.S |
| * |
| * Copyright (C) 1991, 1992 Linus Torvalds |
| * Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs |
| * Copyright (C) 2000 Pavel Machek <pavel@suse.cz> |
| * |
| * $Id$ |
| */ |
| |
| /* |
| * entry.S contains the system-call and fault low-level handling routines. |
| * |
| * NOTE: This code handles signal-recognition, which happens every time |
| * after an interrupt and after each system call. |
| * |
| * Normal syscalls and interrupts don't save a full stack frame, this is |
| * only done for syscall tracing, signals or fork/exec et.al. |
| * |
| * A note on terminology: |
| * - top of stack: Architecture defined interrupt frame from SS to RIP |
| * at the top of the kernel process stack. |
| * - partial stack frame: partially saved registers upto R11. |
| * - full stack frame: Like partial stack frame, but all register saved. |
| * |
| * TODO: |
| * - schedule it carefully for the final hardware. |
| */ |
| |
| #define ASSEMBLY 1 |
| #include <linux/config.h> |
| #include <linux/linkage.h> |
| #include <asm/segment.h> |
| #include <asm/smp.h> |
| #include <asm/cache.h> |
| #include <asm/errno.h> |
| #include <asm/dwarf2.h> |
| #include <asm/calling.h> |
| #include <asm/asm-offsets.h> |
| #include <asm/msr.h> |
| #include <asm/unistd.h> |
| #include <asm/thread_info.h> |
| #include <asm/hw_irq.h> |
| |
| .code64 |
| |
| #ifndef CONFIG_PREEMPT |
| #define retint_kernel retint_restore_args |
| #endif |
| |
| /* |
| * C code is not supposed to know about undefined top of stack. Every time |
| * a C function with an pt_regs argument is called from the SYSCALL based |
| * fast path FIXUP_TOP_OF_STACK is needed. |
| * RESTORE_TOP_OF_STACK syncs the syscall state after any possible ptregs |
| * manipulation. |
| */ |
| |
| /* %rsp:at FRAMEEND */ |
| .macro FIXUP_TOP_OF_STACK tmp |
| movq %gs:pda_oldrsp,\tmp |
| movq \tmp,RSP(%rsp) |
| movq $__USER_DS,SS(%rsp) |
| movq $__USER_CS,CS(%rsp) |
| movq $-1,RCX(%rsp) |
| movq R11(%rsp),\tmp /* get eflags */ |
| movq \tmp,EFLAGS(%rsp) |
| .endm |
| |
| .macro RESTORE_TOP_OF_STACK tmp,offset=0 |
| movq RSP-\offset(%rsp),\tmp |
| movq \tmp,%gs:pda_oldrsp |
| movq EFLAGS-\offset(%rsp),\tmp |
| movq \tmp,R11-\offset(%rsp) |
| .endm |
| |
| .macro FAKE_STACK_FRAME child_rip |
| /* push in order ss, rsp, eflags, cs, rip */ |
| xorl %eax, %eax |
| pushq %rax /* ss */ |
| CFI_ADJUST_CFA_OFFSET 8 |
| pushq %rax /* rsp */ |
| CFI_ADJUST_CFA_OFFSET 8 |
| CFI_OFFSET rip,0 |
| pushq $(1<<9) /* eflags - interrupts on */ |
| CFI_ADJUST_CFA_OFFSET 8 |
| pushq $__KERNEL_CS /* cs */ |
| CFI_ADJUST_CFA_OFFSET 8 |
| pushq \child_rip /* rip */ |
| CFI_ADJUST_CFA_OFFSET 8 |
| CFI_OFFSET rip,0 |
| pushq %rax /* orig rax */ |
| CFI_ADJUST_CFA_OFFSET 8 |
| .endm |
| |
| .macro UNFAKE_STACK_FRAME |
| addq $8*6, %rsp |
| CFI_ADJUST_CFA_OFFSET -(6*8) |
| .endm |
| |
| .macro CFI_DEFAULT_STACK |
| CFI_ADJUST_CFA_OFFSET (SS) |
| CFI_OFFSET r15,R15-SS |
| CFI_OFFSET r14,R14-SS |
| CFI_OFFSET r13,R13-SS |
| CFI_OFFSET r12,R12-SS |
| CFI_OFFSET rbp,RBP-SS |
| CFI_OFFSET rbx,RBX-SS |
| CFI_OFFSET r11,R11-SS |
| CFI_OFFSET r10,R10-SS |
| CFI_OFFSET r9,R9-SS |
| CFI_OFFSET r8,R8-SS |
| CFI_OFFSET rax,RAX-SS |
| CFI_OFFSET rcx,RCX-SS |
| CFI_OFFSET rdx,RDX-SS |
| CFI_OFFSET rsi,RSI-SS |
| CFI_OFFSET rdi,RDI-SS |
| CFI_OFFSET rsp,RSP-SS |
| CFI_OFFSET rip,RIP-SS |
| .endm |
| /* |
| * A newly forked process directly context switches into this. |
| */ |
| /* rdi: prev */ |
| ENTRY(ret_from_fork) |
| CFI_STARTPROC |
| CFI_DEFAULT_STACK |
| call schedule_tail |
| GET_THREAD_INFO(%rcx) |
| testl $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT),threadinfo_flags(%rcx) |
| jnz rff_trace |
| rff_action: |
| RESTORE_REST |
| testl $3,CS-ARGOFFSET(%rsp) # from kernel_thread? |
| je int_ret_from_sys_call |
| testl $_TIF_IA32,threadinfo_flags(%rcx) |
| jnz int_ret_from_sys_call |
| RESTORE_TOP_OF_STACK %rdi,ARGOFFSET |
| jmp ret_from_sys_call |
| rff_trace: |
| movq %rsp,%rdi |
| call syscall_trace_leave |
| GET_THREAD_INFO(%rcx) |
| jmp rff_action |
| CFI_ENDPROC |
| |
| /* |
| * System call entry. Upto 6 arguments in registers are supported. |
| * |
| * SYSCALL does not save anything on the stack and does not change the |
| * stack pointer. |
| */ |
| |
| /* |
| * Register setup: |
| * rax system call number |
| * rdi arg0 |
| * rcx return address for syscall/sysret, C arg3 |
| * rsi arg1 |
| * rdx arg2 |
| * r10 arg3 (--> moved to rcx for C) |
| * r8 arg4 |
| * r9 arg5 |
| * r11 eflags for syscall/sysret, temporary for C |
| * r12-r15,rbp,rbx saved by C code, not touched. |
| * |
| * Interrupts are off on entry. |
| * Only called from user space. |
| * |
| * XXX if we had a free scratch register we could save the RSP into the stack frame |
| * and report it properly in ps. Unfortunately we haven't. |
| */ |
| |
| ENTRY(system_call) |
| CFI_STARTPROC |
| swapgs |
| movq %rsp,%gs:pda_oldrsp |
| movq %gs:pda_kernelstack,%rsp |
| sti |
| SAVE_ARGS 8,1 |
| movq %rax,ORIG_RAX-ARGOFFSET(%rsp) |
| movq %rcx,RIP-ARGOFFSET(%rsp) |
| GET_THREAD_INFO(%rcx) |
| testl $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SECCOMP),threadinfo_flags(%rcx) |
| jnz tracesys |
| cmpq $__NR_syscall_max,%rax |
| ja badsys |
| movq %r10,%rcx |
| call *sys_call_table(,%rax,8) # XXX: rip relative |
| movq %rax,RAX-ARGOFFSET(%rsp) |
| /* |
| * Syscall return path ending with SYSRET (fast path) |
| * Has incomplete stack frame and undefined top of stack. |
| */ |
| .globl ret_from_sys_call |
| ret_from_sys_call: |
| movl $_TIF_ALLWORK_MASK,%edi |
| /* edi: flagmask */ |
| sysret_check: |
| GET_THREAD_INFO(%rcx) |
| cli |
| movl threadinfo_flags(%rcx),%edx |
| andl %edi,%edx |
| jnz sysret_careful |
| movq RIP-ARGOFFSET(%rsp),%rcx |
| RESTORE_ARGS 0,-ARG_SKIP,1 |
| movq %gs:pda_oldrsp,%rsp |
| swapgs |
| sysretq |
| |
| /* Handle reschedules */ |
| /* edx: work, edi: workmask */ |
| sysret_careful: |
| bt $TIF_NEED_RESCHED,%edx |
| jnc sysret_signal |
| sti |
| pushq %rdi |
| call schedule |
| popq %rdi |
| jmp sysret_check |
| |
| /* Handle a signal */ |
| sysret_signal: |
| sti |
| testl $(_TIF_SIGPENDING|_TIF_NOTIFY_RESUME|_TIF_SINGLESTEP),%edx |
| jz 1f |
| |
| /* Really a signal */ |
| /* edx: work flags (arg3) */ |
| leaq do_notify_resume(%rip),%rax |
| leaq -ARGOFFSET(%rsp),%rdi # &pt_regs -> arg1 |
| xorl %esi,%esi # oldset -> arg2 |
| call ptregscall_common |
| 1: movl $_TIF_NEED_RESCHED,%edi |
| jmp sysret_check |
| |
| /* Do syscall tracing */ |
| tracesys: |
| SAVE_REST |
| movq $-ENOSYS,RAX(%rsp) |
| FIXUP_TOP_OF_STACK %rdi |
| movq %rsp,%rdi |
| call syscall_trace_enter |
| LOAD_ARGS ARGOFFSET /* reload args from stack in case ptrace changed it */ |
| RESTORE_REST |
| cmpq $__NR_syscall_max,%rax |
| ja 1f |
| movq %r10,%rcx /* fixup for C */ |
| call *sys_call_table(,%rax,8) |
| movq %rax,RAX-ARGOFFSET(%rsp) |
| 1: SAVE_REST |
| movq %rsp,%rdi |
| call syscall_trace_leave |
| RESTORE_TOP_OF_STACK %rbx |
| RESTORE_REST |
| jmp ret_from_sys_call |
| |
| badsys: |
| movq $-ENOSYS,RAX-ARGOFFSET(%rsp) |
| jmp ret_from_sys_call |
| |
| /* |
| * Syscall return path ending with IRET. |
| * Has correct top of stack, but partial stack frame. |
| */ |
| ENTRY(int_ret_from_sys_call) |
| cli |
| testl $3,CS-ARGOFFSET(%rsp) |
| je retint_restore_args |
| movl $_TIF_ALLWORK_MASK,%edi |
| /* edi: mask to check */ |
| int_with_check: |
| GET_THREAD_INFO(%rcx) |
| movl threadinfo_flags(%rcx),%edx |
| andl %edi,%edx |
| jnz int_careful |
| jmp retint_swapgs |
| |
| /* Either reschedule or signal or syscall exit tracking needed. */ |
| /* First do a reschedule test. */ |
| /* edx: work, edi: workmask */ |
| int_careful: |
| bt $TIF_NEED_RESCHED,%edx |
| jnc int_very_careful |
| sti |
| pushq %rdi |
| call schedule |
| popq %rdi |
| cli |
| jmp int_with_check |
| |
| /* handle signals and tracing -- both require a full stack frame */ |
| int_very_careful: |
| sti |
| SAVE_REST |
| /* Check for syscall exit trace */ |
| testl $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP),%edx |
| jz int_signal |
| pushq %rdi |
| leaq 8(%rsp),%rdi # &ptregs -> arg1 |
| call syscall_trace_leave |
| popq %rdi |
| andl $~(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SINGLESTEP),%edi |
| cli |
| jmp int_restore_rest |
| |
| int_signal: |
| testl $(_TIF_NOTIFY_RESUME|_TIF_SIGPENDING|_TIF_SINGLESTEP),%edx |
| jz 1f |
| movq %rsp,%rdi # &ptregs -> arg1 |
| xorl %esi,%esi # oldset -> arg2 |
| call do_notify_resume |
| 1: movl $_TIF_NEED_RESCHED,%edi |
| int_restore_rest: |
| RESTORE_REST |
| cli |
| jmp int_with_check |
| CFI_ENDPROC |
| |
| /* |
| * Certain special system calls that need to save a complete full stack frame. |
| */ |
| |
| .macro PTREGSCALL label,func,arg |
| .globl \label |
| \label: |
| leaq \func(%rip),%rax |
| leaq -ARGOFFSET+8(%rsp),\arg /* 8 for return address */ |
| jmp ptregscall_common |
| .endm |
| |
| PTREGSCALL stub_clone, sys_clone, %r8 |
| PTREGSCALL stub_fork, sys_fork, %rdi |
| PTREGSCALL stub_vfork, sys_vfork, %rdi |
| PTREGSCALL stub_rt_sigsuspend, sys_rt_sigsuspend, %rdx |
| PTREGSCALL stub_sigaltstack, sys_sigaltstack, %rdx |
| PTREGSCALL stub_iopl, sys_iopl, %rsi |
| |
| ENTRY(ptregscall_common) |
| CFI_STARTPROC |
| popq %r11 |
| CFI_ADJUST_CFA_OFFSET -8 |
| SAVE_REST |
| movq %r11, %r15 |
| FIXUP_TOP_OF_STACK %r11 |
| call *%rax |
| RESTORE_TOP_OF_STACK %r11 |
| movq %r15, %r11 |
| RESTORE_REST |
| pushq %r11 |
| CFI_ADJUST_CFA_OFFSET 8 |
| ret |
| CFI_ENDPROC |
| |
| ENTRY(stub_execve) |
| CFI_STARTPROC |
| popq %r11 |
| CFI_ADJUST_CFA_OFFSET -8 |
| SAVE_REST |
| movq %r11, %r15 |
| FIXUP_TOP_OF_STACK %r11 |
| call sys_execve |
| GET_THREAD_INFO(%rcx) |
| bt $TIF_IA32,threadinfo_flags(%rcx) |
| jc exec_32bit |
| RESTORE_TOP_OF_STACK %r11 |
| movq %r15, %r11 |
| RESTORE_REST |
| push %r11 |
| ret |
| |
| exec_32bit: |
| CFI_ADJUST_CFA_OFFSET REST_SKIP |
| movq %rax,RAX(%rsp) |
| RESTORE_REST |
| jmp int_ret_from_sys_call |
| CFI_ENDPROC |
| |
| /* |
| * sigreturn is special because it needs to restore all registers on return. |
| * This cannot be done with SYSRET, so use the IRET return path instead. |
| */ |
| ENTRY(stub_rt_sigreturn) |
| CFI_STARTPROC |
| addq $8, %rsp |
| SAVE_REST |
| movq %rsp,%rdi |
| FIXUP_TOP_OF_STACK %r11 |
| call sys_rt_sigreturn |
| movq %rax,RAX(%rsp) # fixme, this could be done at the higher layer |
| RESTORE_REST |
| jmp int_ret_from_sys_call |
| CFI_ENDPROC |
| |
| /* |
| * Interrupt entry/exit. |
| * |
| * Interrupt entry points save only callee clobbered registers in fast path. |
| * |
| * Entry runs with interrupts off. |
| */ |
| |
| /* 0(%rsp): interrupt number */ |
| .macro interrupt func |
| CFI_STARTPROC simple |
| CFI_DEF_CFA rsp,(SS-RDI) |
| CFI_REL_OFFSET rsp,(RSP-ORIG_RAX) |
| CFI_REL_OFFSET rip,(RIP-ORIG_RAX) |
| cld |
| #ifdef CONFIG_DEBUG_INFO |
| SAVE_ALL |
| movq %rsp,%rdi |
| /* |
| * Setup a stack frame pointer. This allows gdb to trace |
| * back to the original stack. |
| */ |
| movq %rsp,%rbp |
| CFI_DEF_CFA_REGISTER rbp |
| #else |
| SAVE_ARGS |
| leaq -ARGOFFSET(%rsp),%rdi # arg1 for handler |
| #endif |
| testl $3,CS(%rdi) |
| je 1f |
| swapgs |
| 1: incl %gs:pda_irqcount # RED-PEN should check preempt count |
| movq %gs:pda_irqstackptr,%rax |
| cmoveq %rax,%rsp |
| pushq %rdi # save old stack |
| call \func |
| .endm |
| |
| ENTRY(common_interrupt) |
| interrupt do_IRQ |
| /* 0(%rsp): oldrsp-ARGOFFSET */ |
| ret_from_intr: |
| popq %rdi |
| cli |
| decl %gs:pda_irqcount |
| #ifdef CONFIG_DEBUG_INFO |
| movq RBP(%rdi),%rbp |
| #endif |
| leaq ARGOFFSET(%rdi),%rsp |
| exit_intr: |
| GET_THREAD_INFO(%rcx) |
| testl $3,CS-ARGOFFSET(%rsp) |
| je retint_kernel |
| |
| /* Interrupt came from user space */ |
| /* |
| * Has a correct top of stack, but a partial stack frame |
| * %rcx: thread info. Interrupts off. |
| */ |
| retint_with_reschedule: |
| movl $_TIF_WORK_MASK,%edi |
| retint_check: |
| movl threadinfo_flags(%rcx),%edx |
| andl %edi,%edx |
| jnz retint_careful |
| retint_swapgs: |
| swapgs |
| retint_restore_args: |
| cli |
| RESTORE_ARGS 0,8,0 |
| iret_label: |
| iretq |
| |
| .section __ex_table,"a" |
| .quad iret_label,bad_iret |
| .previous |
| .section .fixup,"ax" |
| /* force a signal here? this matches i386 behaviour */ |
| /* running with kernel gs */ |
| bad_iret: |
| movq $-9999,%rdi /* better code? */ |
| jmp do_exit |
| .previous |
| |
| /* edi: workmask, edx: work */ |
| retint_careful: |
| bt $TIF_NEED_RESCHED,%edx |
| jnc retint_signal |
| sti |
| pushq %rdi |
| call schedule |
| popq %rdi |
| GET_THREAD_INFO(%rcx) |
| cli |
| jmp retint_check |
| |
| retint_signal: |
| testl $(_TIF_SIGPENDING|_TIF_NOTIFY_RESUME|_TIF_SINGLESTEP),%edx |
| jz retint_swapgs |
| sti |
| SAVE_REST |
| movq $-1,ORIG_RAX(%rsp) |
| xorl %esi,%esi # oldset |
| movq %rsp,%rdi # &pt_regs |
| call do_notify_resume |
| RESTORE_REST |
| cli |
| movl $_TIF_NEED_RESCHED,%edi |
| GET_THREAD_INFO(%rcx) |
| jmp retint_check |
| |
| #ifdef CONFIG_PREEMPT |
| /* Returning to kernel space. Check if we need preemption */ |
| /* rcx: threadinfo. interrupts off. */ |
| .p2align |
| retint_kernel: |
| cmpl $0,threadinfo_preempt_count(%rcx) |
| jnz retint_restore_args |
| bt $TIF_NEED_RESCHED,threadinfo_flags(%rcx) |
| jnc retint_restore_args |
| bt $9,EFLAGS-ARGOFFSET(%rsp) /* interrupts off? */ |
| jnc retint_restore_args |
| call preempt_schedule_irq |
| jmp exit_intr |
| #endif |
| CFI_ENDPROC |
| |
| /* |
| * APIC interrupts. |
| */ |
| .macro apicinterrupt num,func |
| pushq $\num-256 |
| interrupt \func |
| jmp ret_from_intr |
| CFI_ENDPROC |
| .endm |
| |
| ENTRY(thermal_interrupt) |
| apicinterrupt THERMAL_APIC_VECTOR,smp_thermal_interrupt |
| |
| #ifdef CONFIG_SMP |
| ENTRY(reschedule_interrupt) |
| apicinterrupt RESCHEDULE_VECTOR,smp_reschedule_interrupt |
| |
| ENTRY(invalidate_interrupt) |
| apicinterrupt INVALIDATE_TLB_VECTOR,smp_invalidate_interrupt |
| |
| ENTRY(call_function_interrupt) |
| apicinterrupt CALL_FUNCTION_VECTOR,smp_call_function_interrupt |
| #endif |
| |
| #ifdef CONFIG_X86_LOCAL_APIC |
| ENTRY(apic_timer_interrupt) |
| apicinterrupt LOCAL_TIMER_VECTOR,smp_apic_timer_interrupt |
| |
| ENTRY(error_interrupt) |
| apicinterrupt ERROR_APIC_VECTOR,smp_error_interrupt |
| |
| ENTRY(spurious_interrupt) |
| apicinterrupt SPURIOUS_APIC_VECTOR,smp_spurious_interrupt |
| #endif |
| |
| /* |
| * Exception entry points. |
| */ |
| .macro zeroentry sym |
| pushq $0 /* push error code/oldrax */ |
| pushq %rax /* push real oldrax to the rdi slot */ |
| leaq \sym(%rip),%rax |
| jmp error_entry |
| .endm |
| |
| .macro errorentry sym |
| pushq %rax |
| leaq \sym(%rip),%rax |
| jmp error_entry |
| .endm |
| |
| /* error code is on the stack already */ |
| /* handle NMI like exceptions that can happen everywhere */ |
| .macro paranoidentry sym |
| SAVE_ALL |
| cld |
| movl $1,%ebx |
| movl $MSR_GS_BASE,%ecx |
| rdmsr |
| testl %edx,%edx |
| js 1f |
| swapgs |
| xorl %ebx,%ebx |
| 1: movq %rsp,%rdi |
| movq ORIG_RAX(%rsp),%rsi |
| movq $-1,ORIG_RAX(%rsp) |
| call \sym |
| cli |
| .endm |
| |
| /* |
| * Exception entry point. This expects an error code/orig_rax on the stack |
| * and the exception handler in %rax. |
| */ |
| ENTRY(error_entry) |
| CFI_STARTPROC simple |
| CFI_DEF_CFA rsp,(SS-RDI) |
| CFI_REL_OFFSET rsp,(RSP-RDI) |
| CFI_REL_OFFSET rip,(RIP-RDI) |
| /* rdi slot contains rax, oldrax contains error code */ |
| cld |
| subq $14*8,%rsp |
| CFI_ADJUST_CFA_OFFSET (14*8) |
| movq %rsi,13*8(%rsp) |
| CFI_REL_OFFSET rsi,RSI |
| movq 14*8(%rsp),%rsi /* load rax from rdi slot */ |
| movq %rdx,12*8(%rsp) |
| CFI_REL_OFFSET rdx,RDX |
| movq %rcx,11*8(%rsp) |
| CFI_REL_OFFSET rcx,RCX |
| movq %rsi,10*8(%rsp) /* store rax */ |
| CFI_REL_OFFSET rax,RAX |
| movq %r8, 9*8(%rsp) |
| CFI_REL_OFFSET r8,R8 |
| movq %r9, 8*8(%rsp) |
| CFI_REL_OFFSET r9,R9 |
| movq %r10,7*8(%rsp) |
| CFI_REL_OFFSET r10,R10 |
| movq %r11,6*8(%rsp) |
| CFI_REL_OFFSET r11,R11 |
| movq %rbx,5*8(%rsp) |
| CFI_REL_OFFSET rbx,RBX |
| movq %rbp,4*8(%rsp) |
| CFI_REL_OFFSET rbp,RBP |
| movq %r12,3*8(%rsp) |
| CFI_REL_OFFSET r12,R12 |
| movq %r13,2*8(%rsp) |
| CFI_REL_OFFSET r13,R13 |
| movq %r14,1*8(%rsp) |
| CFI_REL_OFFSET r14,R14 |
| movq %r15,(%rsp) |
| CFI_REL_OFFSET r15,R15 |
| xorl %ebx,%ebx |
| testl $3,CS(%rsp) |
| je error_kernelspace |
| error_swapgs: |
| swapgs |
| error_sti: |
| movq %rdi,RDI(%rsp) |
| movq %rsp,%rdi |
| movq ORIG_RAX(%rsp),%rsi /* get error code */ |
| movq $-1,ORIG_RAX(%rsp) |
| call *%rax |
| /* ebx: no swapgs flag (1: don't need swapgs, 0: need it) */ |
| error_exit: |
| movl %ebx,%eax |
| RESTORE_REST |
| cli |
| GET_THREAD_INFO(%rcx) |
| testl %eax,%eax |
| jne retint_kernel |
| movl threadinfo_flags(%rcx),%edx |
| movl $_TIF_WORK_MASK,%edi |
| andl %edi,%edx |
| jnz retint_careful |
| swapgs |
| RESTORE_ARGS 0,8,0 |
| iretq |
| CFI_ENDPROC |
| |
| error_kernelspace: |
| incl %ebx |
| /* There are two places in the kernel that can potentially fault with |
| usergs. Handle them here. The exception handlers after |
| iret run with kernel gs again, so don't set the user space flag. |
| B stepping K8s sometimes report an truncated RIP for IRET |
| exceptions returning to compat mode. Check for these here too. */ |
| leaq iret_label(%rip),%rbp |
| cmpq %rbp,RIP(%rsp) |
| je error_swapgs |
| movl %ebp,%ebp /* zero extend */ |
| cmpq %rbp,RIP(%rsp) |
| je error_swapgs |
| cmpq $gs_change,RIP(%rsp) |
| je error_swapgs |
| jmp error_sti |
| |
| /* Reload gs selector with exception handling */ |
| /* edi: new selector */ |
| ENTRY(load_gs_index) |
| pushf |
| cli |
| swapgs |
| gs_change: |
| movl %edi,%gs |
| 2: mfence /* workaround */ |
| swapgs |
| popf |
| ret |
| |
| .section __ex_table,"a" |
| .align 8 |
| .quad gs_change,bad_gs |
| .previous |
| .section .fixup,"ax" |
| /* running with kernelgs */ |
| bad_gs: |
| swapgs /* switch back to user gs */ |
| xorl %eax,%eax |
| movl %eax,%gs |
| jmp 2b |
| .previous |
| |
| /* |
| * Create a kernel thread. |
| * |
| * C extern interface: |
| * extern long kernel_thread(int (*fn)(void *), void * arg, unsigned long flags) |
| * |
| * asm input arguments: |
| * rdi: fn, rsi: arg, rdx: flags |
| */ |
| ENTRY(kernel_thread) |
| CFI_STARTPROC |
| FAKE_STACK_FRAME $child_rip |
| SAVE_ALL |
| |
| # rdi: flags, rsi: usp, rdx: will be &pt_regs |
| movq %rdx,%rdi |
| orq kernel_thread_flags(%rip),%rdi |
| movq $-1, %rsi |
| movq %rsp, %rdx |
| |
| xorl %r8d,%r8d |
| xorl %r9d,%r9d |
| |
| # clone now |
| call do_fork |
| movq %rax,RAX(%rsp) |
| xorl %edi,%edi |
| |
| /* |
| * It isn't worth to check for reschedule here, |
| * so internally to the x86_64 port you can rely on kernel_thread() |
| * not to reschedule the child before returning, this avoids the need |
| * of hacks for example to fork off the per-CPU idle tasks. |
| * [Hopefully no generic code relies on the reschedule -AK] |
| */ |
| RESTORE_ALL |
| UNFAKE_STACK_FRAME |
| ret |
| CFI_ENDPROC |
| |
| |
| child_rip: |
| /* |
| * Here we are in the child and the registers are set as they were |
| * at kernel_thread() invocation in the parent. |
| */ |
| movq %rdi, %rax |
| movq %rsi, %rdi |
| call *%rax |
| # exit |
| xorl %edi, %edi |
| call do_exit |
| |
| /* |
| * execve(). This function needs to use IRET, not SYSRET, to set up all state properly. |
| * |
| * C extern interface: |
| * extern long execve(char *name, char **argv, char **envp) |
| * |
| * asm input arguments: |
| * rdi: name, rsi: argv, rdx: envp |
| * |
| * We want to fallback into: |
| * extern long sys_execve(char *name, char **argv,char **envp, struct pt_regs regs) |
| * |
| * do_sys_execve asm fallback arguments: |
| * rdi: name, rsi: argv, rdx: envp, fake frame on the stack |
| */ |
| ENTRY(execve) |
| CFI_STARTPROC |
| FAKE_STACK_FRAME $0 |
| SAVE_ALL |
| call sys_execve |
| movq %rax, RAX(%rsp) |
| RESTORE_REST |
| testq %rax,%rax |
| je int_ret_from_sys_call |
| RESTORE_ARGS |
| UNFAKE_STACK_FRAME |
| ret |
| CFI_ENDPROC |
| |
| KPROBE_ENTRY(page_fault) |
| errorentry do_page_fault |
| .previous .text |
| |
| ENTRY(coprocessor_error) |
| zeroentry do_coprocessor_error |
| |
| ENTRY(simd_coprocessor_error) |
| zeroentry do_simd_coprocessor_error |
| |
| ENTRY(device_not_available) |
| zeroentry math_state_restore |
| |
| /* runs on exception stack */ |
| KPROBE_ENTRY(debug) |
| CFI_STARTPROC |
| pushq $0 |
| CFI_ADJUST_CFA_OFFSET 8 |
| paranoidentry do_debug |
| jmp paranoid_exit |
| CFI_ENDPROC |
| .previous .text |
| |
| /* runs on exception stack */ |
| ENTRY(nmi) |
| CFI_STARTPROC |
| pushq $-1 |
| CFI_ADJUST_CFA_OFFSET 8 |
| paranoidentry do_nmi |
| /* |
| * "Paranoid" exit path from exception stack. |
| * Paranoid because this is used by NMIs and cannot take |
| * any kernel state for granted. |
| * We don't do kernel preemption checks here, because only |
| * NMI should be common and it does not enable IRQs and |
| * cannot get reschedule ticks. |
| */ |
| /* ebx: no swapgs flag */ |
| paranoid_exit: |
| testl %ebx,%ebx /* swapgs needed? */ |
| jnz paranoid_restore |
| testl $3,CS(%rsp) |
| jnz paranoid_userspace |
| paranoid_swapgs: |
| swapgs |
| paranoid_restore: |
| RESTORE_ALL 8 |
| iretq |
| paranoid_userspace: |
| GET_THREAD_INFO(%rcx) |
| movl threadinfo_flags(%rcx),%ebx |
| andl $_TIF_WORK_MASK,%ebx |
| jz paranoid_swapgs |
| movq %rsp,%rdi /* &pt_regs */ |
| call sync_regs |
| movq %rax,%rsp /* switch stack for scheduling */ |
| testl $_TIF_NEED_RESCHED,%ebx |
| jnz paranoid_schedule |
| movl %ebx,%edx /* arg3: thread flags */ |
| sti |
| xorl %esi,%esi /* arg2: oldset */ |
| movq %rsp,%rdi /* arg1: &pt_regs */ |
| call do_notify_resume |
| cli |
| jmp paranoid_userspace |
| paranoid_schedule: |
| sti |
| call schedule |
| cli |
| jmp paranoid_userspace |
| CFI_ENDPROC |
| |
| KPROBE_ENTRY(int3) |
| zeroentry do_int3 |
| .previous .text |
| |
| ENTRY(overflow) |
| zeroentry do_overflow |
| |
| ENTRY(bounds) |
| zeroentry do_bounds |
| |
| ENTRY(invalid_op) |
| zeroentry do_invalid_op |
| |
| ENTRY(coprocessor_segment_overrun) |
| zeroentry do_coprocessor_segment_overrun |
| |
| ENTRY(reserved) |
| zeroentry do_reserved |
| |
| /* runs on exception stack */ |
| ENTRY(double_fault) |
| CFI_STARTPROC |
| paranoidentry do_double_fault |
| jmp paranoid_exit |
| CFI_ENDPROC |
| |
| ENTRY(invalid_TSS) |
| errorentry do_invalid_TSS |
| |
| ENTRY(segment_not_present) |
| errorentry do_segment_not_present |
| |
| /* runs on exception stack */ |
| ENTRY(stack_segment) |
| CFI_STARTPROC |
| paranoidentry do_stack_segment |
| jmp paranoid_exit |
| CFI_ENDPROC |
| |
| KPROBE_ENTRY(general_protection) |
| errorentry do_general_protection |
| .previous .text |
| |
| ENTRY(alignment_check) |
| errorentry do_alignment_check |
| |
| ENTRY(divide_error) |
| zeroentry do_divide_error |
| |
| ENTRY(spurious_interrupt_bug) |
| zeroentry do_spurious_interrupt_bug |
| |
| #ifdef CONFIG_X86_MCE |
| /* runs on exception stack */ |
| ENTRY(machine_check) |
| CFI_STARTPROC |
| pushq $0 |
| CFI_ADJUST_CFA_OFFSET 8 |
| paranoidentry do_machine_check |
| jmp paranoid_exit |
| CFI_ENDPROC |
| #endif |
| |
| ENTRY(call_debug) |
| zeroentry do_call_debug |
| |
| ENTRY(call_softirq) |
| movq %gs:pda_irqstackptr,%rax |
| pushq %r15 |
| movq %rsp,%r15 |
| incl %gs:pda_irqcount |
| cmove %rax,%rsp |
| call __do_softirq |
| movq %r15,%rsp |
| decl %gs:pda_irqcount |
| popq %r15 |
| ret |
| |
