| /* |
| * 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> |
| */ |
| |
| /* |
| * 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 <linux/linkage.h> |
| #include <asm/segment.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> |
| #include <asm/page.h> |
| #include <asm/irqflags.h> |
| #include <asm/paravirt.h> |
| #include <asm/ftrace.h> |
| |
| /* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this. */ |
| #include <linux/elf-em.h> |
| #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 |
| #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 offset=0 |
| movq %gs:pda_oldrsp,\tmp |
| movq \tmp,RSP+\offset(%rsp) |
| movq $__USER_DS,SS+\offset(%rsp) |
| movq $__USER_CS,CS+\offset(%rsp) |
| movq $-1,RCX+\offset(%rsp) |
| movq R11+\offset(%rsp),\tmp /* get eflags */ |
| movq \tmp,EFLAGS+\offset(%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 $X86_EFLAGS_IF /* 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+\offset-RIP |
| /*CFI_REL_OFFSET ss, SS+\offset-RIP*/ |
| CFI_REL_OFFSET rsp, RSP+\offset-RIP |
| /*CFI_REL_OFFSET rflags, EFLAGS+\offset-RIP*/ |
| /*CFI_REL_OFFSET cs, CS+\offset-RIP*/ |
| CFI_REL_OFFSET rip, RIP+\offset-RIP |
| .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+\offset-ORIG_RAX |
| /*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+\offset-ARGOFFSET |
| CFI_REL_OFFSET rdi, RDI+\offset-ARGOFFSET |
| CFI_REL_OFFSET rsi, RSI+\offset-ARGOFFSET |
| CFI_REL_OFFSET rdx, RDX+\offset-ARGOFFSET |
| CFI_REL_OFFSET rcx, RCX+\offset-ARGOFFSET |
| CFI_REL_OFFSET rax, RAX+\offset-ARGOFFSET |
| CFI_REL_OFFSET r8, R8+\offset-ARGOFFSET |
| CFI_REL_OFFSET r9, R9+\offset-ARGOFFSET |
| CFI_REL_OFFSET r10, R10+\offset-ARGOFFSET |
| CFI_REL_OFFSET r11, R11+\offset-ARGOFFSET |
| .endm |
| |
| /* |
| * frame that enables passing a complete pt_regs to a C function. |
| */ |
| .macro DEFAULT_FRAME start=1 offset=0 |
| PARTIAL_FRAME \start, R11+\offset-R15 |
| 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 |
| movq_cfi rdi, RDI+16-ARGOFFSET |
| movq_cfi rsi, RSI+16-ARGOFFSET |
| movq_cfi rdx, RDX+16-ARGOFFSET |
| movq_cfi rcx, RCX+16-ARGOFFSET |
| movq_cfi rax, RAX+16-ARGOFFSET |
| movq_cfi r8, R8+16-ARGOFFSET |
| movq_cfi r9, R9+16-ARGOFFSET |
| movq_cfi r10, R10+16-ARGOFFSET |
| movq_cfi r11, R11+16-ARGOFFSET |
| |
| leaq -ARGOFFSET+16(%rsp),%rdi /* arg1 for handler */ |
| movq_cfi 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 |
| popq_cfi %rax /* move return address... */ |
| mov %gs:pda_irqstackptr,%rsp |
| EMPTY_FRAME 0 |
| pushq_cfi %rax /* ... to the new stack */ |
| /* |
| * We entered an interrupt context - irqs are off: |
| */ |
| 2: TRACE_IRQS_OFF |
| ret |
| CFI_ENDPROC |
| END(save_args) |
| |
| ENTRY(save_rest) |
| PARTIAL_FRAME 1 REST_SKIP+8 |
| movq 5*8+16(%rsp), %r11 /* save return address */ |
| movq_cfi rbx, RBX+16 |
| movq_cfi rbp, RBP+16 |
| movq_cfi r12, R12+16 |
| movq_cfi r13, R13+16 |
| movq_cfi r14, R14+16 |
| movq_cfi r15, R15+16 |
| movq %r11, 8(%rsp) /* return address */ |
| FIXUP_TOP_OF_STACK %r11, 16 |
| ret |
| CFI_ENDPROC |
| END(save_rest) |
| |
| /* save complete stack frame */ |
| ENTRY(save_paranoid) |
| XCPT_FRAME 1 RDI+8 |
| cld |
| movq_cfi rdi, RDI+8 |
| movq_cfi rsi, RSI+8 |
| movq_cfi rdx, RDX+8 |
| movq_cfi rcx, RCX+8 |
| movq_cfi rax, RAX+8 |
| movq_cfi r8, R8+8 |
| movq_cfi r9, R9+8 |
| movq_cfi r10, R10+8 |
| movq_cfi r11, R11+8 |
| movq_cfi rbx, RBX+8 |
| movq_cfi rbp, RBP+8 |
| movq_cfi r12, R12+8 |
| movq_cfi r13, R13+8 |
| movq_cfi r14, R14+8 |
| movq_cfi r15, R15+8 |
| movl $1,%ebx |
| movl $MSR_GS_BASE,%ecx |
| rdmsr |
| testl %edx,%edx |
| js 1f /* negative -> in kernel */ |
| SWAPGS |
| xorl %ebx,%ebx |
| 1: ret |
| CFI_ENDPROC |
| END(save_paranoid) |
| |
| /* |
| * A newly forked process directly context switches into this address. |
| * |
| * rdi: prev task we switched from |
| */ |
| 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 # rdi: 'prev' task parameter |
| |
| GET_THREAD_INFO(%rcx) |
| |
| CFI_REMEMBER_STATE |
| RESTORE_REST |
| |
| testl $3, CS-ARGOFFSET(%rsp) # from kernel_thread? |
| je int_ret_from_sys_call |
| |
| testl $_TIF_IA32, TI_flags(%rcx) # 32-bit compat task needs IRET |
| jnz int_ret_from_sys_call |
| |
| RESTORE_TOP_OF_STACK %rdi, -ARGOFFSET |
| jmp ret_from_sys_call # go to the SYSRET fastpath |
| |
| CFI_RESTORE_STATE |
| 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 -ARGOFFSET(%rsp),%rdi # &pt_regs -> arg1 |
| xorl %esi,%esi # oldset -> arg2 |
| SAVE_REST |
| FIXUP_TOP_OF_STACK %r11 |
| call do_notify_resume |
| RESTORE_TOP_OF_STACK %r11 |
| RESTORE_REST |
| 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 |
| ENTRY(\label) |
| PARTIAL_FRAME 1 8 /* offset 8: return address */ |
| subq $REST_SKIP, %rsp |
| CFI_ADJUST_CFA_OFFSET REST_SKIP |
| call save_rest |
| DEFAULT_FRAME 0 8 /* offset 8: return address */ |
| leaq 8(%rsp), \arg /* pt_regs pointer */ |
| call \func |
| jmp ptregscall_common |
| CFI_ENDPROC |
| END(\label) |
| .endm |
| |
| 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) |
| DEFAULT_FRAME 1 8 /* offset 8: return address */ |
| RESTORE_TOP_OF_STACK %r11, 8 |
| movq_cfi_restore R15+8, r15 |
| movq_cfi_restore R14+8, r14 |
| movq_cfi_restore R13+8, r13 |
| movq_cfi_restore R12+8, r12 |
| movq_cfi_restore RBP+8, rbp |
| movq_cfi_restore RBX+8, rbx |
| ret $REST_SKIP /* pop extended registers */ |
| 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. |
| */ |
| .macro apicinterrupt num sym do_sym |
| ENTRY(\sym) |
| INTR_FRAME |
| pushq $~(\num) |
| CFI_ADJUST_CFA_OFFSET 8 |
| interrupt \do_sym |
| jmp ret_from_intr |
| CFI_ENDPROC |
| END(\sym) |
| .endm |
| |
| #ifdef CONFIG_SMP |
| apicinterrupt IRQ_MOVE_CLEANUP_VECTOR \ |
| irq_move_cleanup_interrupt smp_irq_move_cleanup_interrupt |
| #endif |
| |
| apicinterrupt UV_BAU_MESSAGE \ |
| uv_bau_message_intr1 uv_bau_message_interrupt |
| apicinterrupt LOCAL_TIMER_VECTOR \ |
| apic_timer_interrupt smp_apic_timer_interrupt |
| |
| #ifdef CONFIG_SMP |
| apicinterrupt INVALIDATE_TLB_VECTOR_START+0 \ |
| invalidate_interrupt0 smp_invalidate_interrupt |
| apicinterrupt INVALIDATE_TLB_VECTOR_START+1 \ |
| invalidate_interrupt1 smp_invalidate_interrupt |
| apicinterrupt INVALIDATE_TLB_VECTOR_START+2 \ |
| invalidate_interrupt2 smp_invalidate_interrupt |
| apicinterrupt INVALIDATE_TLB_VECTOR_START+3 \ |
| invalidate_interrupt3 smp_invalidate_interrupt |
| apicinterrupt INVALIDATE_TLB_VECTOR_START+4 \ |
| invalidate_interrupt4 smp_invalidate_interrupt |
| apicinterrupt INVALIDATE_TLB_VECTOR_START+5 \ |
| invalidate_interrupt5 smp_invalidate_interrupt |
| apicinterrupt INVALIDATE_TLB_VECTOR_START+6 \ |
| invalidate_interrupt6 smp_invalidate_interrupt |
| apicinterrupt INVALIDATE_TLB_VECTOR_START+7 \ |
| invalidate_interrupt7 smp_invalidate_interrupt |
| #endif |
| |
| apicinterrupt THRESHOLD_APIC_VECTOR \ |
| threshold_interrupt mce_threshold_interrupt |
| apicinterrupt THERMAL_APIC_VECTOR \ |
| thermal_interrupt smp_thermal_interrupt |
| |
| #ifdef CONFIG_SMP |
| apicinterrupt CALL_FUNCTION_SINGLE_VECTOR \ |
| call_function_single_interrupt smp_call_function_single_interrupt |
| apicinterrupt CALL_FUNCTION_VECTOR \ |
| call_function_interrupt smp_call_function_interrupt |
| apicinterrupt RESCHEDULE_VECTOR \ |
| reschedule_interrupt smp_reschedule_interrupt |
| #endif |
| |
| apicinterrupt ERROR_APIC_VECTOR \ |
| error_interrupt smp_error_interrupt |
| apicinterrupt SPURIOUS_APIC_VECTOR \ |
| spurious_interrupt smp_spurious_interrupt |
| |
| #ifdef CONFIG_PERF_COUNTERS |
| apicinterrupt LOCAL_PERF_VECTOR \ |
| perf_counter_interrupt smp_perf_counter_interrupt |
| #endif |
| |
| /* |
| * Exception entry points. |
| */ |
| .macro zeroentry sym do_sym |
| ENTRY(\sym) |
| INTR_FRAME |
| PARAVIRT_ADJUST_EXCEPTION_FRAME |
| pushq_cfi $-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 \do_sym |
| jmp error_exit /* %ebx: no swapgs flag */ |
| CFI_ENDPROC |
| END(\sym) |
| .endm |
| |
| .macro paranoidzeroentry sym do_sym |
| ENTRY(\sym) |
| INTR_FRAME |
| PARAVIRT_ADJUST_EXCEPTION_FRAME |
| pushq $-1 /* ORIG_RAX: no syscall to restart */ |
| CFI_ADJUST_CFA_OFFSET 8 |
| subq $15*8, %rsp |
| call save_paranoid |
| TRACE_IRQS_OFF |
| movq %rsp,%rdi /* pt_regs pointer */ |
| xorl %esi,%esi /* no error code */ |
| call \do_sym |
| jmp paranoid_exit /* %ebx: no swapgs flag */ |
| CFI_ENDPROC |
| END(\sym) |
| .endm |
| |
| .macro paranoidzeroentry_ist sym do_sym ist |
| ENTRY(\sym) |
| INTR_FRAME |
| PARAVIRT_ADJUST_EXCEPTION_FRAME |
| pushq $-1 /* ORIG_RAX: no syscall to restart */ |
| CFI_ADJUST_CFA_OFFSET 8 |
| subq $15*8, %rsp |
| call save_paranoid |
| TRACE_IRQS_OFF |
| movq %rsp,%rdi /* pt_regs pointer */ |
| xorl %esi,%esi /* no error code */ |
| movq %gs:pda_data_offset, %rbp |
| subq $EXCEPTION_STKSZ, per_cpu__init_tss + TSS_ist + (\ist - 1) * 8(%rbp) |
| call \do_sym |
| addq $EXCEPTION_STKSZ, per_cpu__init_tss + TSS_ist + (\ist - 1) * 8(%rbp) |
| jmp paranoid_exit /* %ebx: no swapgs flag */ |
| CFI_ENDPROC |
| END(\sym) |
| .endm |
| |
| .macro errorentry sym do_sym |
| ENTRY(\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 \do_sym |
| jmp error_exit /* %ebx: no swapgs flag */ |
| CFI_ENDPROC |
| END(\sym) |
| .endm |
| |
| /* error code is on the stack already */ |
| .macro paranoiderrorentry sym do_sym |
| ENTRY(\sym) |
| XCPT_FRAME |
| PARAVIRT_ADJUST_EXCEPTION_FRAME |
| subq $15*8,%rsp |
| CFI_ADJUST_CFA_OFFSET 15*8 |
| call save_paranoid |
| DEFAULT_FRAME 0 |
| TRACE_IRQS_OFF |
| movq %rsp,%rdi /* pt_regs pointer */ |
| movq ORIG_RAX(%rsp),%rsi /* get error code */ |
| movq $-1,ORIG_RAX(%rsp) /* no syscall to restart */ |
| call \do_sym |
| jmp paranoid_exit /* %ebx: no swapgs flag */ |
| CFI_ENDPROC |
| END(\sym) |
| .endm |
| |
| zeroentry divide_error do_divide_error |
| zeroentry overflow do_overflow |
| zeroentry bounds do_bounds |
| zeroentry invalid_op do_invalid_op |
| zeroentry device_not_available do_device_not_available |
| paranoiderrorentry double_fault do_double_fault |
| zeroentry coprocessor_segment_overrun do_coprocessor_segment_overrun |
| errorentry invalid_TSS do_invalid_TSS |
| errorentry segment_not_present do_segment_not_present |
| zeroentry spurious_interrupt_bug do_spurious_interrupt_bug |
| zeroentry coprocessor_error do_coprocessor_error |
| errorentry alignment_check do_alignment_check |
| zeroentry simd_coprocessor_error do_simd_coprocessor_error |
| |
| /* 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 |
| END(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 |
| END(kernel_thread) |
| |
| ENTRY(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 |
| ud2 # padding for call trace |
| CFI_ENDPROC |
| END(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 |
| END(kernel_execve) |
| |
| /* 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 |
| END(call_softirq) |
| |
| #ifdef CONFIG_XEN |
| zeroentry xen_hypervisor_callback xen_do_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 |
| pushq_cfi $0 /* RIP */ |
| pushq_cfi %r11 |
| pushq_cfi %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 |
| pushq_cfi $0 |
| SAVE_ALL |
| jmp error_exit |
| CFI_ENDPROC |
| END(xen_failsafe_callback) |
| |
| #endif /* CONFIG_XEN */ |
| |
| /* |
| * Some functions should be protected against kprobes |
| */ |
| .pushsection .kprobes.text, "ax" |
| |
| paranoidzeroentry_ist debug do_debug DEBUG_STACK |
| paranoidzeroentry_ist int3 do_int3 DEBUG_STACK |
| paranoiderrorentry stack_segment do_stack_segment |
| errorentry general_protection do_general_protection |
| errorentry page_fault do_page_fault |
| #ifdef CONFIG_X86_MCE |
| paranoidzeroentry machine_check do_machine_check |
| #endif |
| |
| /* |
| * "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) |
| */ |
| |
| /* ebx: no swapgs flag */ |
| ENTRY(paranoid_exit) |
| INTR_FRAME |
| DISABLE_INTERRUPTS(CLBR_NONE) |
| TRACE_IRQS_OFF |
| testl %ebx,%ebx /* swapgs needed? */ |
| jnz paranoid_restore |
| testl $3,CS(%rsp) |
| jnz paranoid_userspace |
| paranoid_swapgs: |
| TRACE_IRQS_IRETQ 0 |
| SWAPGS_UNSAFE_STACK |
| paranoid_restore: |
| RESTORE_ALL 8 |
| jmp irq_return |
| paranoid_userspace: |
| GET_THREAD_INFO(%rcx) |
| movl TI_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 */ |
| TRACE_IRQS_ON |
| ENABLE_INTERRUPTS(CLBR_NONE) |
| xorl %esi,%esi /* arg2: oldset */ |
| movq %rsp,%rdi /* arg1: &pt_regs */ |
| call do_notify_resume |
| DISABLE_INTERRUPTS(CLBR_NONE) |
| TRACE_IRQS_OFF |
| jmp paranoid_userspace |
| paranoid_schedule: |
| TRACE_IRQS_ON |
| ENABLE_INTERRUPTS(CLBR_ANY) |
| call schedule |
| DISABLE_INTERRUPTS(CLBR_ANY) |
| TRACE_IRQS_OFF |
| jmp paranoid_userspace |
| CFI_ENDPROC |
| END(paranoid_exit) |
| |
| /* |
| * Exception entry point. This expects an error code/orig_rax on the stack. |
| * returns in "no swapgs flag" in %ebx. |
| */ |
| ENTRY(error_entry) |
| XCPT_FRAME |
| CFI_ADJUST_CFA_OFFSET 15*8 |
| /* oldrax contains error code */ |
| cld |
| movq_cfi rdi, RDI+8 |
| movq_cfi rsi, RSI+8 |
| movq_cfi rdx, RDX+8 |
| movq_cfi rcx, RCX+8 |
| movq_cfi rax, RAX+8 |
| movq_cfi r8, R8+8 |
| movq_cfi r9, R9+8 |
| movq_cfi r10, R10+8 |
| movq_cfi r11, R11+8 |
| movq_cfi rbx, RBX+8 |
| movq_cfi rbp, RBP+8 |
| movq_cfi r12, R12+8 |
| movq_cfi r13, R13+8 |
| movq_cfi r14, R14+8 |
| movq_cfi 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 |
| END(error_entry) |
| |
| |
| /* ebx: no swapgs flag (1: don't need swapgs, 0: need it) */ |
| 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 |
| END(error_exit) |
| |
| |
| /* runs on exception stack */ |
| ENTRY(nmi) |
| INTR_FRAME |
| PARAVIRT_ADJUST_EXCEPTION_FRAME |
| pushq_cfi $-1 |
| subq $15*8, %rsp |
| CFI_ADJUST_CFA_OFFSET 15*8 |
| call save_paranoid |
| DEFAULT_FRAME 0 |
| /* paranoidentry do_nmi, 0; without TRACE_IRQS_OFF */ |
| movq %rsp,%rdi |
| movq $-1,%rsi |
| call do_nmi |
| #ifdef CONFIG_TRACE_IRQFLAGS |
| /* paranoidexit; without TRACE_IRQS_OFF */ |
| /* ebx: no swapgs flag */ |
| DISABLE_INTERRUPTS(CLBR_NONE) |
| testl %ebx,%ebx /* swapgs needed? */ |
| jnz nmi_restore |
| testl $3,CS(%rsp) |
| jnz nmi_userspace |
| nmi_swapgs: |
| SWAPGS_UNSAFE_STACK |
| nmi_restore: |
| RESTORE_ALL 8 |
| jmp irq_return |
| nmi_userspace: |
| GET_THREAD_INFO(%rcx) |
| movl TI_flags(%rcx),%ebx |
| andl $_TIF_WORK_MASK,%ebx |
| jz nmi_swapgs |
| movq %rsp,%rdi /* &pt_regs */ |
| call sync_regs |
| movq %rax,%rsp /* switch stack for scheduling */ |
| testl $_TIF_NEED_RESCHED,%ebx |
| jnz nmi_schedule |
| movl %ebx,%edx /* arg3: thread flags */ |
| ENABLE_INTERRUPTS(CLBR_NONE) |
| xorl %esi,%esi /* arg2: oldset */ |
| movq %rsp,%rdi /* arg1: &pt_regs */ |
| call do_notify_resume |
| DISABLE_INTERRUPTS(CLBR_NONE) |
| jmp nmi_userspace |
| nmi_schedule: |
| ENABLE_INTERRUPTS(CLBR_ANY) |
| call schedule |
| DISABLE_INTERRUPTS(CLBR_ANY) |
| jmp nmi_userspace |
| CFI_ENDPROC |
| #else |
| jmp paranoid_exit |
| CFI_ENDPROC |
| #endif |
| END(nmi) |
| |
| ENTRY(ignore_sysret) |
| CFI_STARTPROC |
| mov $-ENOSYS,%eax |
| sysret |
| CFI_ENDPROC |
| END(ignore_sysret) |
| |
| /* |
| * End of kprobes section |
| */ |
| .popsection |
