/* * 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 */ /* * 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. * * Some macro usage: * - CFI macros are used to generate dwarf2 unwind information for better * backtraces. They don't change any code. * - SAVE_ALL/RESTORE_ALL - Save/restore all registers * - SAVE_ARGS/RESTORE_ARGS - Save/restore registers that C functions modify. * There are unfortunately lots of special cases where some registers * not touched. The macro is a big mess that should be cleaned up. * - SAVE_REST/RESTORE_REST - Handle the registers not saved by SAVE_ARGS. * Gives a full stack frame. * - ENTRY/END Define functions in the symbol table. * - FIXUP_TOP_OF_STACK/RESTORE_TOP_OF_STACK - Fix up the hardware stack * frame that is otherwise undefined after a SYSCALL * - TRACE_IRQ_* - Trace hard interrupt state for lock debugging. * - errorentry/paranoidentry/zeroentry - Define exception entry points. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* Avoid __ASSEMBLER__'ifying just for this. */ #include #define AUDIT_ARCH_X86_64 (EM_X86_64|__AUDIT_ARCH_64BIT|__AUDIT_ARCH_LE) #define __AUDIT_ARCH_64BIT 0x80000000 #define __AUDIT_ARCH_LE 0x40000000 .code64 /* * Some macro's to hide the most frequently occuring CFI annotations. */ .macro CFI_PUSHQ reg pushq \reg CFI_ADJUST_CFA_OFFSET 8 .endm .macro CFI_POPQ reg popq \reg CFI_ADJUST_CFA_OFFSET -8 .endm .macro CFI_MOVQ reg offset=0 movq %\reg, \offset(%rsp) CFI_REL_OFFSET \reg, \offset .endm #ifdef CONFIG_FUNCTION_TRACER #ifdef CONFIG_DYNAMIC_FTRACE ENTRY(mcount) retq END(mcount) ENTRY(ftrace_caller) /* taken from glibc */ subq $0x38, %rsp movq %rax, (%rsp) movq %rcx, 8(%rsp) movq %rdx, 16(%rsp) movq %rsi, 24(%rsp) movq %rdi, 32(%rsp) movq %r8, 40(%rsp) movq %r9, 48(%rsp) movq 0x38(%rsp), %rdi movq 8(%rbp), %rsi subq $MCOUNT_INSN_SIZE, %rdi .globl ftrace_call ftrace_call: call ftrace_stub movq 48(%rsp), %r9 movq 40(%rsp), %r8 movq 32(%rsp), %rdi movq 24(%rsp), %rsi movq 16(%rsp), %rdx movq 8(%rsp), %rcx movq (%rsp), %rax addq $0x38, %rsp .globl ftrace_stub ftrace_stub: retq END(ftrace_caller) #else /* ! CONFIG_DYNAMIC_FTRACE */ ENTRY(mcount) cmpq $ftrace_stub, ftrace_trace_function jnz trace .globl ftrace_stub ftrace_stub: retq trace: /* taken from glibc */ subq $0x38, %rsp movq %rax, (%rsp) movq %rcx, 8(%rsp) movq %rdx, 16(%rsp) movq %rsi, 24(%rsp) movq %rdi, 32(%rsp) movq %r8, 40(%rsp) movq %r9, 48(%rsp) movq 0x38(%rsp), %rdi movq 8(%rbp), %rsi subq $MCOUNT_INSN_SIZE, %rdi call *ftrace_trace_function movq 48(%rsp), %r9 movq 40(%rsp), %r8 movq 32(%rsp), %rdi movq 24(%rsp), %rsi movq 16(%rsp), %rdx movq 8(%rsp), %rcx movq (%rsp), %rax addq $0x38, %rsp jmp ftrace_stub END(mcount) #endif /* CONFIG_DYNAMIC_FTRACE */ #endif /* CONFIG_FUNCTION_TRACER */ #ifndef CONFIG_PREEMPT #define retint_kernel retint_restore_args #endif #ifdef CONFIG_PARAVIRT ENTRY(native_usergs_sysret64) swapgs sysretq #endif /* CONFIG_PARAVIRT */ .macro TRACE_IRQS_IRETQ offset=ARGOFFSET #ifdef CONFIG_TRACE_IRQFLAGS bt $9,EFLAGS-\offset(%rsp) /* interrupts off? */ jnc 1f TRACE_IRQS_ON 1: #endif .endm /* * 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 $__KERNEL_DS /* ss */ CFI_ADJUST_CFA_OFFSET 8 /*CFI_REL_OFFSET ss,0*/ pushq %rax /* rsp */ CFI_ADJUST_CFA_OFFSET 8 CFI_REL_OFFSET rsp,0 pushq $(1<<9) /* eflags - interrupts on */ CFI_ADJUST_CFA_OFFSET 8 /*CFI_REL_OFFSET rflags,0*/ pushq $__KERNEL_CS /* cs */ CFI_ADJUST_CFA_OFFSET 8 /*CFI_REL_OFFSET cs,0*/ pushq \child_rip /* rip */ CFI_ADJUST_CFA_OFFSET 8 CFI_REL_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 /* * initial frame state for interrupts (and exceptions without error code) */ .macro EMPTY_FRAME start=1 offset=0 .if \start CFI_STARTPROC simple CFI_SIGNAL_FRAME CFI_DEF_CFA rsp,8+\offset .else CFI_DEF_CFA_OFFSET 8+\offset .endif .endm /* * initial frame state for interrupts (and exceptions without error code) */ .macro INTR_FRAME start=1 offset=0 EMPTY_FRAME \start, (SS+8-RIP)+\offset /*CFI_REL_OFFSET ss, SS-RIP+\offset*/ CFI_REL_OFFSET rsp, RSP-RIP+\offset /*CFI_REL_OFFSET rflags, EFLAGS-RIP+\offset*/ /*CFI_REL_OFFSET cs, CS-RIP+\offset*/ CFI_REL_OFFSET rip, RIP-RIP+\offset .endm /* * initial frame state for exceptions with error code (and interrupts * with vector already pushed) */ .macro XCPT_FRAME start=1 offset=0 INTR_FRAME \start, (RIP-ORIG_RAX)+\offset /*CFI_REL_OFFSET orig_rax, ORIG_RAX-ORIG_RAX*/ .endm /* * frame that enables calling into C. */ .macro PARTIAL_FRAME start=1 offset=0 XCPT_FRAME \start, (ORIG_RAX-ARGOFFSET)+\offset CFI_REL_OFFSET rdi, (RDI-ARGOFFSET)+\offset CFI_REL_OFFSET rsi, (RSI-ARGOFFSET)+\offset CFI_REL_OFFSET rdx, (RDX-ARGOFFSET)+\offset CFI_REL_OFFSET rcx, (RCX-ARGOFFSET)+\offset CFI_REL_OFFSET rax, (RAX-ARGOFFSET)+\offset CFI_REL_OFFSET r8, (R8-ARGOFFSET)+\offset CFI_REL_OFFSET r9, (R9-ARGOFFSET)+\offset CFI_REL_OFFSET r10, (R10-ARGOFFSET)+\offset CFI_REL_OFFSET r11, (R11-ARGOFFSET)+\offset .endm /* * frame that enables passing a complete pt_regs to a C function. */ .macro DEFAULT_FRAME start=1 offset=0 PARTIAL_FRAME \start, (R11-R15)+\offset CFI_REL_OFFSET rbx, RBX+\offset CFI_REL_OFFSET rbp, RBP+\offset CFI_REL_OFFSET r12, R12+\offset CFI_REL_OFFSET r13, R13+\offset CFI_REL_OFFSET r14, R14+\offset CFI_REL_OFFSET r15, R15+\offset .endm /* save partial stack frame */ ENTRY(save_args) XCPT_FRAME cld CFI_MOVQ rdi, (RDI-ARGOFFSET)+16 CFI_MOVQ rsi, (RSI-ARGOFFSET)+16 CFI_MOVQ rdx, (RDX-ARGOFFSET)+16 CFI_MOVQ rcx, (RCX-ARGOFFSET)+16 CFI_MOVQ rax, (RAX-ARGOFFSET)+16 CFI_MOVQ r8, (R8-ARGOFFSET)+16 CFI_MOVQ r9, (R9-ARGOFFSET)+16 CFI_MOVQ r10, (R10-ARGOFFSET)+16 CFI_MOVQ r11, (R11-ARGOFFSET)+16 leaq -ARGOFFSET+16(%rsp),%rdi /* arg1 for handler */ CFI_MOVQ rbp, 8 /* push %rbp */ leaq 8(%rsp), %rbp /* mov %rsp, %ebp */ testl $3, CS(%rdi) je 1f SWAPGS /* * irqcount is used to check if a CPU is already on an interrupt stack * or not. While this is essentially redundant with preempt_count it is * a little cheaper to use a separate counter in the PDA (short of * moving irq_enter into assembly, which would be too much work) */ 1: incl %gs:pda_irqcount jne 2f CFI_POPQ %rax /* move return address... */ mov %gs:pda_irqstackptr,%rsp EMPTY_FRAME 0 CFI_PUSHQ %rax /* ... to the new stack */ /* * We entered an interrupt context - irqs are off: */ 2: TRACE_IRQS_OFF ret CFI_ENDPROC END(save_args) /* * A newly forked process directly context switches into this. */ /* rdi: prev */ ENTRY(ret_from_fork) DEFAULT_FRAME push kernel_eflags(%rip) CFI_ADJUST_CFA_OFFSET 8 popf # reset kernel eflags CFI_ADJUST_CFA_OFFSET -8 call schedule_tail GET_THREAD_INFO(%rcx) testl $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT),TI_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,TI_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 END(ret_from_fork) /* * 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. * * When user can change the frames always force IRET. That is because * it deals with uncanonical addresses better. SYSRET has trouble * with them due to bugs in both AMD and Intel CPUs. */ ENTRY(system_call) CFI_STARTPROC simple CFI_SIGNAL_FRAME CFI_DEF_CFA rsp,PDA_STACKOFFSET CFI_REGISTER rip,rcx /*CFI_REGISTER rflags,r11*/ SWAPGS_UNSAFE_STACK /* * A hypervisor implementation might want to use a label * after the swapgs, so that it can do the swapgs * for the guest and jump here on syscall. */ ENTRY(system_call_after_swapgs) movq %rsp,%gs:pda_oldrsp movq %gs:pda_kernelstack,%rsp /* * No need to follow this irqs off/on section - it's straight * and short: */ ENABLE_INTERRUPTS(CLBR_NONE) SAVE_ARGS 8,1 movq %rax,ORIG_RAX-ARGOFFSET(%rsp) movq %rcx,RIP-ARGOFFSET(%rsp) CFI_REL_OFFSET rip,RIP-ARGOFFSET GET_THREAD_INFO(%rcx) testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags(%rcx) jnz tracesys system_call_fastpath: 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. */ ret_from_sys_call: movl $_TIF_ALLWORK_MASK,%edi /* edi: flagmask */ sysret_check: LOCKDEP_SYS_EXIT GET_THREAD_INFO(%rcx) DISABLE_INTERRUPTS(CLBR_NONE) TRACE_IRQS_OFF movl TI_flags(%rcx),%edx andl %edi,%edx jnz sysret_careful CFI_REMEMBER_STATE /* * sysretq will re-enable interrupts: */ TRACE_IRQS_ON movq RIP-ARGOFFSET(%rsp),%rcx CFI_REGISTER rip,rcx RESTORE_ARGS 0,-ARG_SKIP,1 /*CFI_REGISTER rflags,r11*/ movq %gs:pda_oldrsp, %rsp USERGS_SYSRET64 CFI_RESTORE_STATE /* Handle reschedules */ /* edx: work, edi: workmask */ sysret_careful: bt $TIF_NEED_RESCHED,%edx jnc sysret_signal TRACE_IRQS_ON ENABLE_INTERRUPTS(CLBR_NONE) pushq %rdi CFI_ADJUST_CFA_OFFSET 8 call schedule popq %rdi CFI_ADJUST_CFA_OFFSET -8 jmp sysret_check /* Handle a signal */ sysret_signal: TRACE_IRQS_ON ENABLE_INTERRUPTS(CLBR_NONE) #ifdef CONFIG_AUDITSYSCALL bt $TIF_SYSCALL_AUDIT,%edx jc sysret_audit #endif /* 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 movl $_TIF_WORK_MASK,%edi /* Use IRET because user could have changed frame. This works because ptregscall_common has called FIXUP_TOP_OF_STACK. */ DISABLE_INTERRUPTS(CLBR_NONE) TRACE_IRQS_OFF jmp int_with_check badsys: movq $-ENOSYS,RAX-ARGOFFSET(%rsp) jmp ret_from_sys_call #ifdef CONFIG_AUDITSYSCALL /* * Fast path for syscall audit without full syscall trace. * We just call audit_syscall_entry() directly, and then * jump back to the normal fast path. */ auditsys: movq %r10,%r9 /* 6th arg: 4th syscall arg */ movq %rdx,%r8 /* 5th arg: 3rd syscall arg */ movq %rsi,%rcx /* 4th arg: 2nd syscall arg */ movq %rdi,%rdx /* 3rd arg: 1st syscall arg */ movq %rax,%rsi /* 2nd arg: syscall number */ movl $AUDIT_ARCH_X86_64,%edi /* 1st arg: audit arch */ call audit_syscall_entry LOAD_ARGS 0 /* reload call-clobbered registers */ jmp system_call_fastpath /* * Return fast path for syscall audit. Call audit_syscall_exit() * directly and then jump back to the fast path with TIF_SYSCALL_AUDIT * masked off. */ sysret_audit: movq %rax,%rsi /* second arg, syscall return value */ cmpq $0,%rax /* is it < 0? */ setl %al /* 1 if so, 0 if not */ movzbl %al,%edi /* zero-extend that into %edi */ inc %edi /* first arg, 0->1(AUDITSC_SUCCESS), 1->2(AUDITSC_FAILURE) */ call audit_syscall_exit movl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),%edi jmp sysret_check #endif /* CONFIG_AUDITSYSCALL */ /* Do syscall tracing */ tracesys: #ifdef CONFIG_AUDITSYSCALL testl $(_TIF_WORK_SYSCALL_ENTRY & ~_TIF_SYSCALL_AUDIT),TI_flags(%rcx) jz auditsys #endif SAVE_REST movq $-ENOSYS,RAX(%rsp) /* ptrace can change this for a bad syscall */ FIXUP_TOP_OF_STACK %rdi movq %rsp,%rdi call syscall_trace_enter /* * Reload arg registers from stack in case ptrace changed them. * We don't reload %rax because syscall_trace_enter() returned * the value it wants us to use in the table lookup. */ LOAD_ARGS ARGOFFSET, 1 RESTORE_REST cmpq $__NR_syscall_max,%rax ja int_ret_from_sys_call /* RAX(%rsp) set to -ENOSYS above */ movq %r10,%rcx /* fixup for C */ call *sys_call_table(,%rax,8) movq %rax,RAX-ARGOFFSET(%rsp) /* Use IRET because user could have changed frame */ /* * Syscall return path ending with IRET. * Has correct top of stack, but partial stack frame. */ .globl int_ret_from_sys_call .globl int_with_check int_ret_from_sys_call: DISABLE_INTERRUPTS(CLBR_NONE) TRACE_IRQS_OFF testl $3,CS-ARGOFFSET(%rsp) je retint_restore_args movl $_TIF_ALLWORK_MASK,%edi /* edi: mask to check */ int_with_check: LOCKDEP_SYS_EXIT_IRQ GET_THREAD_INFO(%rcx) movl TI_flags(%rcx),%edx andl %edi,%edx jnz int_careful andl $~TS_COMPAT,TI_status(%rcx) 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 TRACE_IRQS_ON ENABLE_INTERRUPTS(CLBR_NONE) pushq %rdi CFI_ADJUST_CFA_OFFSET 8 call schedule popq %rdi CFI_ADJUST_CFA_OFFSET -8 DISABLE_INTERRUPTS(CLBR_NONE) TRACE_IRQS_OFF jmp int_with_check /* handle signals and tracing -- both require a full stack frame */ int_very_careful: TRACE_IRQS_ON ENABLE_INTERRUPTS(CLBR_NONE) SAVE_REST /* Check for syscall exit trace */ testl $_TIF_WORK_SYSCALL_EXIT,%edx jz int_signal pushq %rdi CFI_ADJUST_CFA_OFFSET 8 leaq 8(%rsp),%rdi # &ptregs -> arg1 call syscall_trace_leave popq %rdi CFI_ADJUST_CFA_OFFSET -8 andl $~(_TIF_WORK_SYSCALL_EXIT|_TIF_SYSCALL_EMU),%edi jmp int_restore_rest int_signal: testl $_TIF_DO_NOTIFY_MASK,%edx jz 1f movq %rsp,%rdi # &ptregs -> arg1 xorl %esi,%esi # oldset -> arg2 call do_notify_resume 1: movl $_TIF_WORK_MASK,%edi int_restore_rest: RESTORE_REST DISABLE_INTERRUPTS(CLBR_NONE) TRACE_IRQS_OFF jmp int_with_check CFI_ENDPROC END(system_call) /* * 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 END(\label) .endm CFI_STARTPROC PTREGSCALL stub_clone, sys_clone, %r8 PTREGSCALL stub_fork, sys_fork, %rdi PTREGSCALL stub_vfork, sys_vfork, %rdi PTREGSCALL stub_sigaltstack, sys_sigaltstack, %rdx PTREGSCALL stub_iopl, sys_iopl, %rsi ENTRY(ptregscall_common) popq %r11 CFI_ADJUST_CFA_OFFSET -8 CFI_REGISTER rip, r11 SAVE_REST movq %r11, %r15 CFI_REGISTER rip, r15 FIXUP_TOP_OF_STACK %r11 call *%rax RESTORE_TOP_OF_STACK %r11 movq %r15, %r11 CFI_REGISTER rip, r11 RESTORE_REST pushq %r11 CFI_ADJUST_CFA_OFFSET 8 CFI_REL_OFFSET rip, 0 ret CFI_ENDPROC END(ptregscall_common) ENTRY(stub_execve) CFI_STARTPROC popq %r11 CFI_ADJUST_CFA_OFFSET -8 CFI_REGISTER rip, r11 SAVE_REST FIXUP_TOP_OF_STACK %r11 movq %rsp, %rcx call sys_execve RESTORE_TOP_OF_STACK %r11 movq %rax,RAX(%rsp) RESTORE_REST jmp int_ret_from_sys_call CFI_ENDPROC END(stub_execve) /* * 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 CFI_ADJUST_CFA_OFFSET -8 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 END(stub_rt_sigreturn) /* * Build the entry stubs and pointer table with some assembler magic. * We pack 7 stubs into a single 32-byte chunk, which will fit in a * single cache line on all modern x86 implementations. */ .section .init.rodata,"a" ENTRY(interrupt) .text .p2align 5 .p2align CONFIG_X86_L1_CACHE_SHIFT ENTRY(irq_entries_start) INTR_FRAME vector=FIRST_EXTERNAL_VECTOR .rept (NR_VECTORS-FIRST_EXTERNAL_VECTOR+6)/7 .balign 32 .rept 7 .if vector < NR_VECTORS .if vector <> FIRST_EXTERNAL_VECTOR CFI_ADJUST_CFA_OFFSET -8 .endif 1: pushq $(~vector+0x80) /* Note: always in signed byte range */ CFI_ADJUST_CFA_OFFSET 8 .if ((vector-FIRST_EXTERNAL_VECTOR)%7) <> 6 jmp 2f .endif .previous .quad 1b .text vector=vector+1 .endif .endr 2: jmp common_interrupt .endr CFI_ENDPROC END(irq_entries_start) .previous END(interrupt) .previous /* * 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 subq $10*8, %rsp CFI_ADJUST_CFA_OFFSET 10*8 call save_args PARTIAL_FRAME 0 call \func .endm /* * The interrupt stubs push (~vector+0x80) onto the stack and * then jump to common_interrupt. */ .p2align CONFIG_X86_L1_CACHE_SHIFT common_interrupt: XCPT_FRAME addq $-0x80,(%rsp) /* Adjust vector to [-256,-1] range */ interrupt do_IRQ /* 0(%rsp): oldrsp-ARGOFFSET */ ret_from_intr: DISABLE_INTERRUPTS(CLBR_NONE) TRACE_IRQS_OFF decl %gs:pda_irqcount leaveq CFI_DEF_CFA_REGISTER rsp CFI_ADJUST_CFA_OFFSET -8 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: LOCKDEP_SYS_EXIT_IRQ movl TI_flags(%rcx),%edx andl %edi,%edx CFI_REMEMBER_STATE jnz retint_careful retint_swapgs: /* return to user-space */ /* * The iretq could re-enable interrupts: */ DISABLE_INTERRUPTS(CLBR_ANY) TRACE_IRQS_IRETQ SWAPGS jmp restore_args retint_restore_args: /* return to kernel space */ DISABLE_INTERRUPTS(CLBR_ANY) /* * The iretq could re-enable interrupts: */ TRACE_IRQS_IRETQ restore_args: RESTORE_ARGS 0,8,0 irq_return: INTERRUPT_RETURN .section __ex_table, "a" .quad irq_return, bad_iret .previous #ifdef CONFIG_PARAVIRT ENTRY(native_iret) iretq .section __ex_table,"a" .quad native_iret, bad_iret .previous #endif .section .fixup,"ax" bad_iret: /* * The iret traps when the %cs or %ss being restored is bogus. * We've lost the original trap vector and error code. * #GPF is the most likely one to get for an invalid selector. * So pretend we completed the iret and took the #GPF in user mode. * * We are now running with the kernel GS after exception recovery. * But error_entry expects us to have user GS to match the user %cs, * so swap back. */ pushq $0 SWAPGS jmp general_protection .previous /* edi: workmask, edx: work */ retint_careful: CFI_RESTORE_STATE bt $TIF_NEED_RESCHED,%edx jnc retint_signal TRACE_IRQS_ON ENABLE_INTERRUPTS(CLBR_NONE) pushq %rdi CFI_ADJUST_CFA_OFFSET 8 call schedule popq %rdi CFI_ADJUST_CFA_OFFSET -8 GET_THREAD_INFO(%rcx) DISABLE_INTERRUPTS(CLBR_NONE) TRACE_IRQS_OFF jmp retint_check retint_signal: testl $_TIF_DO_NOTIFY_MASK,%edx jz retint_swapgs TRACE_IRQS_ON ENABLE_INTERRUPTS(CLBR_NONE) SAVE_REST movq $-1,ORIG_RAX(%rsp) xorl %esi,%esi # oldset movq %rsp,%rdi # &pt_regs call do_notify_resume RESTORE_REST DISABLE_INTERRUPTS(CLBR_NONE) TRACE_IRQS_OFF GET_THREAD_INFO(%rcx) jmp retint_with_reschedule #ifdef CONFIG_PREEMPT /* Returning to kernel space. Check if we need preemption */ /* rcx: threadinfo. interrupts off. */ ENTRY(retint_kernel) cmpl $0,TI_preempt_count(%rcx) jnz retint_restore_args bt $TIF_NEED_RESCHED,TI_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 END(common_interrupt) /* * APIC interrupts. */ .p2align 5 .macro apicinterrupt num,func INTR_FRAME pushq $~(\num) CFI_ADJUST_CFA_OFFSET 8 interrupt \func jmp ret_from_intr CFI_ENDPROC .endm ENTRY(thermal_interrupt) apicinterrupt THERMAL_APIC_VECTOR,smp_thermal_interrupt END(thermal_interrupt) ENTRY(threshold_interrupt) apicinterrupt THRESHOLD_APIC_VECTOR,mce_threshold_interrupt END(threshold_interrupt) #ifdef CONFIG_SMP ENTRY(reschedule_interrupt) apicinterrupt RESCHEDULE_VECTOR,smp_reschedule_interrupt END(reschedule_interrupt) .macro INVALIDATE_ENTRY num ENTRY(invalidate_interrupt\num) apicinterrupt INVALIDATE_TLB_VECTOR_START+\num,smp_invalidate_interrupt END(invalidate_interrupt\num) .endm INVALIDATE_ENTRY 0 INVALIDATE_ENTRY 1 INVALIDATE_ENTRY 2 INVALIDATE_ENTRY 3 INVALIDATE_ENTRY 4 INVALIDATE_ENTRY 5 INVALIDATE_ENTRY 6 INVALIDATE_ENTRY 7 ENTRY(call_function_interrupt) apicinterrupt CALL_FUNCTION_VECTOR,smp_call_function_interrupt END(call_function_interrupt) ENTRY(call_function_single_interrupt) apicinterrupt CALL_FUNCTION_SINGLE_VECTOR,smp_call_function_single_interrupt END(call_function_single_interrupt) ENTRY(irq_move_cleanup_interrupt) apicinterrupt IRQ_MOVE_CLEANUP_VECTOR,smp_irq_move_cleanup_interrupt END(irq_move_cleanup_interrupt) #endif ENTRY(apic_timer_interrupt) apicinterrupt LOCAL_TIMER_VECTOR,smp_apic_timer_interrupt END(apic_timer_interrupt) ENTRY(uv_bau_message_intr1) apicinterrupt 220,uv_bau_message_interrupt END(uv_bau_message_intr1) ENTRY(error_interrupt) apicinterrupt ERROR_APIC_VECTOR,smp_error_interrupt END(error_interrupt) ENTRY(spurious_interrupt) apicinterrupt SPURIOUS_APIC_VECTOR,smp_spurious_interrupt END(spurious_interrupt) /* * Exception entry points. */ .macro zeroentry sym INTR_FRAME PARAVIRT_ADJUST_EXCEPTION_FRAME CFI_PUSHQ $-1 /* ORIG_RAX: no syscall to restart */ subq $15*8,%rsp CFI_ADJUST_CFA_OFFSET 15*8 call error_entry DEFAULT_FRAME 0 movq %rsp,%rdi /* pt_regs pointer */ xorl %esi,%esi /* no error code */ call \sym jmp error_exit /* %ebx: no swapgs flag */ CFI_ENDPROC .endm .macro errorentry sym XCPT_FRAME PARAVIRT_ADJUST_EXCEPTION_FRAME subq $15*8,%rsp CFI_ADJUST_CFA_OFFSET 15*8 call error_entry DEFAULT_FRAME 0 movq %rsp,%rdi /* pt_regs pointer */ movq ORIG_RAX(%rsp),%rsi /* get error code */ movq $-1,ORIG_RAX(%rsp) /* no syscall to restart */ call \sym jmp error_exit /* %ebx: no swapgs flag */ CFI_ENDPROC .endm /* error code is on the stack already */ /* handle NMI like exceptions that can happen everywhere */ .macro paranoidentry sym, ist=0, irqtrace=1 SAVE_ALL cld movl $1,%ebx movl $MSR_GS_BASE,%ecx rdmsr testl %edx,%edx js 1f SWAPGS xorl %ebx,%ebx 1: .if \ist movq %gs:pda_data_offset, %rbp .endif .if \irqtrace TRACE_IRQS_OFF .endif movq %rsp,%rdi movq ORIG_RAX(%rsp),%rsi movq $-1,ORIG_RAX(%rsp) .if \ist subq $EXCEPTION_STKSZ, per_cpu__init_tss + TSS_ist + (\ist - 1) * 8(%rbp) .endif call \sym .if \ist addq $EXCEPTION_STKSZ, per_cpu__init_tss + TSS_ist + (\ist - 1) * 8(%rbp) .endif DISABLE_INTERRUPTS(CLBR_NONE) .if \irqtrace TRACE_IRQS_OFF .endif .endm /* * "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. * * "trace" is 0 for the NMI handler only, because irq-tracing * is fundamentally NMI-unsafe. (we cannot change the soft and * hard flags at once, atomically) */ .macro paranoidexit trace=1 /* ebx: no swapgs flag */ paranoid_exit\trace: testl %ebx,%ebx /* swapgs needed? */ jnz paranoid_restore\trace testl $3,CS(%rsp) jnz paranoid_userspace\trace paranoid_swapgs\trace: .if \trace TRACE_IRQS_IRETQ 0 .endif SWAPGS_UNSAFE_STACK paranoid_restore\trace: RESTORE_ALL 8 jmp irq_return paranoid_userspace\trace: GET_THREAD_INFO(%rcx) movl TI_flags(%rcx),%ebx andl $_TIF_WORK_MASK,%ebx jz paranoid_swapgs\trace movq %rsp,%rdi /* &pt_regs */ call sync_regs movq %rax,%rsp /* switch stack for scheduling */ testl $_TIF_NEED_RESCHED,%ebx jnz paranoid_schedule\trace movl %ebx,%edx /* arg3: thread flags */ .if \trace TRACE_IRQS_ON .endif ENABLE_INTERRUPTS(CLBR_NONE) xorl %esi,%esi /* arg2: oldset */ movq %rsp,%rdi /* arg1: &pt_regs */ call do_notify_resume DISABLE_INTERRUPTS(CLBR_NONE) .if \trace TRACE_IRQS_OFF .endif jmp paranoid_userspace\trace paranoid_schedule\trace: .if \trace TRACE_IRQS_ON .endif ENABLE_INTERRUPTS(CLBR_ANY) call schedule DISABLE_INTERRUPTS(CLBR_ANY) .if \trace TRACE_IRQS_OFF .endif jmp paranoid_userspace\trace CFI_ENDPROC .endm /* * Exception entry point. This expects an error code/orig_rax on the stack. * returns in "no swapgs flag" in %ebx. */ KPROBE_ENTRY(error_entry) XCPT_FRAME CFI_ADJUST_CFA_OFFSET 15*8 /* oldrax contains error code */ cld CFI_MOVQ rdi, RDI+8 CFI_MOVQ rsi, RSI+8 CFI_MOVQ rdx, RDX+8 CFI_MOVQ rcx, RCX+8 CFI_MOVQ rax, RAX+8 CFI_MOVQ r8, R8+8 CFI_MOVQ r9, R9+8 CFI_MOVQ r10, R10+8 CFI_MOVQ r11, R11+8 CFI_MOVQ rbx, RBX+8 CFI_MOVQ rbp, RBP+8 CFI_MOVQ r12, R12+8 CFI_MOVQ r13, R13+8 CFI_MOVQ r14, R14+8 CFI_MOVQ r15, R15+8 xorl %ebx,%ebx testl $3,CS+8(%rsp) je error_kernelspace error_swapgs: SWAPGS error_sti: TRACE_IRQS_OFF ret CFI_ENDPROC /* * 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. */ error_kernelspace: incl %ebx leaq irq_return(%rip),%rcx cmpq %rcx,RIP+8(%rsp) je error_swapgs movl %ecx,%ecx /* zero extend */ cmpq %rcx,RIP+8(%rsp) je error_swapgs cmpq $gs_change,RIP+8(%rsp) je error_swapgs jmp error_sti KPROBE_END(error_entry) /* ebx: no swapgs flag (1: don't need swapgs, 0: need it) */ KPROBE_ENTRY(error_exit) DEFAULT_FRAME movl %ebx,%eax RESTORE_REST DISABLE_INTERRUPTS(CLBR_NONE) TRACE_IRQS_OFF GET_THREAD_INFO(%rcx) testl %eax,%eax jne retint_kernel LOCKDEP_SYS_EXIT_IRQ movl TI_flags(%rcx),%edx movl $_TIF_WORK_MASK,%edi andl %edi,%edx jnz retint_careful jmp retint_swapgs CFI_ENDPROC KPROBE_END(error_exit) /* Reload gs selector with exception handling */ /* edi: new selector */ ENTRY(native_load_gs_index) CFI_STARTPROC pushf CFI_ADJUST_CFA_OFFSET 8 DISABLE_INTERRUPTS(CLBR_ANY | ~(CLBR_RDI)) SWAPGS gs_change: movl %edi,%gs 2: mfence /* workaround */ SWAPGS popf CFI_ADJUST_CFA_OFFSET -8 ret CFI_ENDPROC ENDPROC(native_load_gs_index) .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 ENDPROC(kernel_thread) child_rip: pushq $0 # fake return address CFI_STARTPROC /* * 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 mov %eax, %edi call do_exit CFI_ENDPROC ENDPROC(child_rip) /* * 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, rcx: fake frame on the stack */ ENTRY(kernel_execve) CFI_STARTPROC FAKE_STACK_FRAME $0 SAVE_ALL movq %rsp,%rcx 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 ENDPROC(kernel_execve) KPROBE_ENTRY(page_fault) errorentry do_page_fault KPROBE_END(page_fault) ENTRY(coprocessor_error) zeroentry do_coprocessor_error END(coprocessor_error) ENTRY(simd_coprocessor_error) zeroentry do_simd_coprocessor_error END(simd_coprocessor_error) ENTRY(device_not_available) zeroentry do_device_not_available END(device_not_available) /* runs on exception stack */ KPROBE_ENTRY(debug) INTR_FRAME PARAVIRT_ADJUST_EXCEPTION_FRAME pushq $0 CFI_ADJUST_CFA_OFFSET 8 paranoidentry do_debug, DEBUG_STACK paranoidexit KPROBE_END(debug) /* runs on exception stack */ KPROBE_ENTRY(nmi) INTR_FRAME PARAVIRT_ADJUST_EXCEPTION_FRAME pushq $-1 CFI_ADJUST_CFA_OFFSET 8 paranoidentry do_nmi, 0, 0 #ifdef CONFIG_TRACE_IRQFLAGS paranoidexit 0 #else jmp paranoid_exit1 CFI_ENDPROC #endif KPROBE_END(nmi) KPROBE_ENTRY(int3) INTR_FRAME PARAVIRT_ADJUST_EXCEPTION_FRAME pushq $0 CFI_ADJUST_CFA_OFFSET 8 paranoidentry do_int3, DEBUG_STACK jmp paranoid_exit1 CFI_ENDPROC KPROBE_END(int3) ENTRY(overflow) zeroentry do_overflow END(overflow) ENTRY(bounds) zeroentry do_bounds END(bounds) ENTRY(invalid_op) zeroentry do_invalid_op END(invalid_op) ENTRY(coprocessor_segment_overrun) zeroentry do_coprocessor_segment_overrun END(coprocessor_segment_overrun) /* runs on exception stack */ ENTRY(double_fault) XCPT_FRAME PARAVIRT_ADJUST_EXCEPTION_FRAME paranoidentry do_double_fault jmp paranoid_exit1 CFI_ENDPROC END(double_fault) ENTRY(invalid_TSS) errorentry do_invalid_TSS END(invalid_TSS) ENTRY(segment_not_present) errorentry do_segment_not_present END(segment_not_present) /* runs on exception stack */ ENTRY(stack_segment) XCPT_FRAME PARAVIRT_ADJUST_EXCEPTION_FRAME paranoidentry do_stack_segment jmp paranoid_exit1 CFI_ENDPROC END(stack_segment) KPROBE_ENTRY(general_protection) errorentry do_general_protection KPROBE_END(general_protection) ENTRY(alignment_check) errorentry do_alignment_check END(alignment_check) ENTRY(divide_error) zeroentry do_divide_error END(divide_error) ENTRY(spurious_interrupt_bug) zeroentry do_spurious_interrupt_bug END(spurious_interrupt_bug) #ifdef CONFIG_X86_MCE /* runs on exception stack */ ENTRY(machine_check) INTR_FRAME PARAVIRT_ADJUST_EXCEPTION_FRAME pushq $0 CFI_ADJUST_CFA_OFFSET 8 paranoidentry do_machine_check jmp paranoid_exit1 CFI_ENDPROC END(machine_check) #endif /* Call softirq on interrupt stack. Interrupts are off. */ ENTRY(call_softirq) CFI_STARTPROC push %rbp CFI_ADJUST_CFA_OFFSET 8 CFI_REL_OFFSET rbp,0 mov %rsp,%rbp CFI_DEF_CFA_REGISTER rbp incl %gs:pda_irqcount cmove %gs:pda_irqstackptr,%rsp push %rbp # backlink for old unwinder call __do_softirq leaveq CFI_DEF_CFA_REGISTER rsp CFI_ADJUST_CFA_OFFSET -8 decl %gs:pda_irqcount ret CFI_ENDPROC ENDPROC(call_softirq) KPROBE_ENTRY(ignore_sysret) CFI_STARTPROC mov $-ENOSYS,%eax sysret CFI_ENDPROC ENDPROC(ignore_sysret) #ifdef CONFIG_XEN ENTRY(xen_hypervisor_callback) zeroentry xen_do_hypervisor_callback END(xen_hypervisor_callback) /* # A note on the "critical region" in our callback handler. # We want to avoid stacking callback handlers due to events occurring # during handling of the last event. To do this, we keep events disabled # until we've done all processing. HOWEVER, we must enable events before # popping the stack frame (can't be done atomically) and so it would still # be possible to get enough handler activations to overflow the stack. # Although unlikely, bugs of that kind are hard to track down, so we'd # like to avoid the possibility. # So, on entry to the handler we detect whether we interrupted an # existing activation in its critical region -- if so, we pop the current # activation and restart the handler using the previous one. */ ENTRY(xen_do_hypervisor_callback) # do_hypervisor_callback(struct *pt_regs) CFI_STARTPROC /* Since we don't modify %rdi, evtchn_do_upall(struct *pt_regs) will see the correct pointer to the pt_regs */ movq %rdi, %rsp # we don't return, adjust the stack frame CFI_ENDPROC DEFAULT_FRAME 11: incl %gs:pda_irqcount movq %rsp,%rbp CFI_DEF_CFA_REGISTER rbp cmovzq %gs:pda_irqstackptr,%rsp pushq %rbp # backlink for old unwinder call xen_evtchn_do_upcall popq %rsp CFI_DEF_CFA_REGISTER rsp decl %gs:pda_irqcount jmp error_exit CFI_ENDPROC END(do_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 do not need to fix up as Xen has already reloaded all segment # registers that could be reloaded and zeroed the others. # Category 2 we fix up by killing the current process. 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 comparing each saved segment register # with its current contents: any discrepancy means we in category 1. */ ENTRY(xen_failsafe_callback) INTR_FRAME 1 (6*8) /*CFI_REL_OFFSET gs,GS*/ /*CFI_REL_OFFSET fs,FS*/ /*CFI_REL_OFFSET es,ES*/ /*CFI_REL_OFFSET ds,DS*/ CFI_REL_OFFSET r11,8 CFI_REL_OFFSET rcx,0 movw %ds,%cx cmpw %cx,0x10(%rsp) CFI_REMEMBER_STATE jne 1f movw %es,%cx cmpw %cx,0x18(%rsp) jne 1f movw %fs,%cx cmpw %cx,0x20(%rsp) jne 1f movw %gs,%cx cmpw %cx,0x28(%rsp) jne 1f /* All segments match their saved values => Category 2 (Bad IRET). */ movq (%rsp),%rcx CFI_RESTORE rcx movq 8(%rsp),%r11 CFI_RESTORE r11 addq $0x30,%rsp CFI_ADJUST_CFA_OFFSET -0x30 CFI_PUSHQ $0 /* RIP */ CFI_PUSHQ %r11 CFI_PUSHQ %rcx jmp general_protection CFI_RESTORE_STATE 1: /* Segment mismatch => Category 1 (Bad segment). Retry the IRET. */ movq (%rsp),%rcx CFI_RESTORE rcx movq 8(%rsp),%r11 CFI_RESTORE r11 addq $0x30,%rsp CFI_ADJUST_CFA_OFFSET -0x30 CFI_PUSHQ $0 SAVE_ALL jmp error_exit CFI_ENDPROC END(xen_failsafe_callback) #endif /* CONFIG_XEN */