| /* |
| * 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. |
| * |
| * Some of this is documented in Documentation/x86/entry_64.txt |
| * |
| * 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 up to 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. |
| * - idtentry - 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_types.h> |
| #include <asm/irqflags.h> |
| #include <asm/paravirt.h> |
| #include <asm/percpu.h> |
| #include <asm/asm.h> |
| #include <asm/context_tracking.h> |
| #include <asm/smap.h> |
| #include <asm/pgtable_types.h> |
| #include <linux/err.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 |
| .section .entry.text, "ax" |
| |
| |
| #ifndef CONFIG_PREEMPT |
| #define retint_kernel retint_restore_args |
| #endif |
| |
| #ifdef CONFIG_PARAVIRT |
| ENTRY(native_usergs_sysret64) |
| swapgs |
| sysretq |
| ENDPROC(native_usergs_sysret64) |
| #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 |
| |
| /* |
| * When dynamic function tracer is enabled it will add a breakpoint |
| * to all locations that it is about to modify, sync CPUs, update |
| * all the code, sync CPUs, then remove the breakpoints. In this time |
| * if lockdep is enabled, it might jump back into the debug handler |
| * outside the updating of the IST protection. (TRACE_IRQS_ON/OFF). |
| * |
| * We need to change the IDT table before calling TRACE_IRQS_ON/OFF to |
| * make sure the stack pointer does not get reset back to the top |
| * of the debug stack, and instead just reuses the current stack. |
| */ |
| #if defined(CONFIG_DYNAMIC_FTRACE) && defined(CONFIG_TRACE_IRQFLAGS) |
| |
| .macro TRACE_IRQS_OFF_DEBUG |
| call debug_stack_set_zero |
| TRACE_IRQS_OFF |
| call debug_stack_reset |
| .endm |
| |
| .macro TRACE_IRQS_ON_DEBUG |
| call debug_stack_set_zero |
| TRACE_IRQS_ON |
| call debug_stack_reset |
| .endm |
| |
| .macro TRACE_IRQS_IRETQ_DEBUG offset=ARGOFFSET |
| bt $9,EFLAGS-\offset(%rsp) /* interrupts off? */ |
| jnc 1f |
| TRACE_IRQS_ON_DEBUG |
| 1: |
| .endm |
| |
| #else |
| # define TRACE_IRQS_OFF_DEBUG TRACE_IRQS_OFF |
| # define TRACE_IRQS_ON_DEBUG TRACE_IRQS_ON |
| # define TRACE_IRQS_IRETQ_DEBUG TRACE_IRQS_IRETQ |
| #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 offset=0 |
| movq PER_CPU_VAR(old_rsp),\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,PER_CPU_VAR(old_rsp) |
| 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_cfi $__KERNEL_DS /* ss */ |
| /*CFI_REL_OFFSET ss,0*/ |
| pushq_cfi %rax /* rsp */ |
| CFI_REL_OFFSET rsp,0 |
| pushq_cfi $(X86_EFLAGS_IF|X86_EFLAGS_FIXED) /* eflags - interrupts on */ |
| /*CFI_REL_OFFSET rflags,0*/ |
| pushq_cfi $__KERNEL_CS /* cs */ |
| /*CFI_REL_OFFSET cs,0*/ |
| pushq_cfi \child_rip /* rip */ |
| CFI_REL_OFFSET rip,0 |
| pushq_cfi %rax /* orig rax */ |
| .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 |
| .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 */ |
| .macro SAVE_ARGS_IRQ |
| cld |
| /* start from rbp in pt_regs and jump over */ |
| movq_cfi rdi, (RDI-RBP) |
| movq_cfi rsi, (RSI-RBP) |
| movq_cfi rdx, (RDX-RBP) |
| movq_cfi rcx, (RCX-RBP) |
| movq_cfi rax, (RAX-RBP) |
| movq_cfi r8, (R8-RBP) |
| movq_cfi r9, (R9-RBP) |
| movq_cfi r10, (R10-RBP) |
| movq_cfi r11, (R11-RBP) |
| |
| /* Save rbp so that we can unwind from get_irq_regs() */ |
| movq_cfi rbp, 0 |
| |
| /* Save previous stack value */ |
| movq %rsp, %rsi |
| |
| leaq -RBP(%rsp),%rdi /* arg1 for handler */ |
| testl $3, CS-RBP(%rsi) |
| je 1f |
| SWAPGS |
| /* |
| * irq_count 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 PER_CPU_VAR(irq_count) |
| cmovzq PER_CPU_VAR(irq_stack_ptr),%rsp |
| CFI_DEF_CFA_REGISTER rsi |
| |
| /* Store previous stack value */ |
| pushq %rsi |
| CFI_ESCAPE 0x0f /* DW_CFA_def_cfa_expression */, 6, \ |
| 0x77 /* DW_OP_breg7 */, 0, \ |
| 0x06 /* DW_OP_deref */, \ |
| 0x08 /* DW_OP_const1u */, SS+8-RBP, \ |
| 0x22 /* DW_OP_plus */ |
| /* We entered an interrupt context - irqs are off: */ |
| TRACE_IRQS_OFF |
| .endm |
| |
| ENTRY(save_paranoid) |
| XCPT_FRAME 1 RDI+8 |
| cld |
| movq %rdi, RDI+8(%rsp) |
| movq %rsi, RSI+8(%rsp) |
| movq_cfi rdx, RDX+8 |
| movq_cfi rcx, RCX+8 |
| movq_cfi rax, RAX+8 |
| movq %r8, R8+8(%rsp) |
| movq %r9, R9+8(%rsp) |
| movq %r10, R10+8(%rsp) |
| movq %r11, R11+8(%rsp) |
| movq_cfi rbx, RBX+8 |
| movq %rbp, RBP+8(%rsp) |
| movq %r12, R12+8(%rsp) |
| movq %r13, R13+8(%rsp) |
| movq %r14, R14+8(%rsp) |
| movq %r15, R15+8(%rsp) |
| 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 |
| |
| LOCK ; btr $TIF_FORK,TI_flags(%r8) |
| |
| pushq_cfi $0x0002 |
| popfq_cfi # reset kernel eflags |
| |
| call schedule_tail # rdi: 'prev' task parameter |
| |
| GET_THREAD_INFO(%rcx) |
| |
| RESTORE_REST |
| |
| testl $3, CS-ARGOFFSET(%rsp) # from kernel_thread? |
| jz 1f |
| |
| 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 |
| |
| 1: |
| subq $REST_SKIP, %rsp # leave space for volatiles |
| CFI_ADJUST_CFA_OFFSET REST_SKIP |
| movq %rbp, %rdi |
| call *%rbx |
| movl $0, RAX(%rsp) |
| RESTORE_REST |
| jmp int_ret_from_sys_call |
| CFI_ENDPROC |
| END(ret_from_fork) |
| |
| /* |
| * System call entry. Up to 6 arguments in registers are supported. |
| * |
| * SYSCALL does not save anything on the stack and does not change the |
| * stack pointer. However, it does mask the flags register for us, so |
| * CLD and CLAC are not needed. |
| */ |
| |
| /* |
| * 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,KERNEL_STACK_OFFSET |
| 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. |
| */ |
| GLOBAL(system_call_after_swapgs) |
| |
| movq %rsp,PER_CPU_VAR(old_rsp) |
| movq PER_CPU_VAR(kernel_stack),%rsp |
| /* |
| * No need to follow this irqs off/on section - it's straight |
| * and short: |
| */ |
| ENABLE_INTERRUPTS(CLBR_NONE) |
| SAVE_ARGS 8, 0, rax_enosys=1 |
| movq_cfi rax,(ORIG_RAX-ARGOFFSET) |
| movq %rcx,RIP-ARGOFFSET(%rsp) |
| CFI_REL_OFFSET rip,RIP-ARGOFFSET |
| testl $_TIF_WORK_SYSCALL_ENTRY,TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET) |
| jnz tracesys |
| system_call_fastpath: |
| #if __SYSCALL_MASK == ~0 |
| cmpq $__NR_syscall_max,%rax |
| #else |
| andl $__SYSCALL_MASK,%eax |
| cmpl $__NR_syscall_max,%eax |
| #endif |
| ja ret_from_sys_call /* and return regs->ax */ |
| 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 |
| DISABLE_INTERRUPTS(CLBR_NONE) |
| TRACE_IRQS_OFF |
| movl TI_flags+THREAD_INFO(%rsp,RIP-ARGOFFSET),%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 1,-ARG_SKIP,0 |
| /*CFI_REGISTER rflags,r11*/ |
| movq PER_CPU_VAR(old_rsp), %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_cfi %rdi |
| SCHEDULE_USER |
| popq_cfi %rdi |
| 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 |
| /* |
| * We have a signal, or exit tracing or single-step. |
| * These all wind up with the iret return path anyway, |
| * so just join that path right now. |
| */ |
| FIXUP_TOP_OF_STACK %r11, -ARGOFFSET |
| jmp int_check_syscall_exit_work |
| |
| #ifdef CONFIG_AUDITSYSCALL |
| /* |
| * 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-ARGOFFSET(%rsp),%rsi /* second arg, syscall return value */ |
| cmpq $-MAX_ERRNO,%rsi /* is it < -MAX_ERRNO? */ |
| setbe %al /* 1 if so, 0 if not */ |
| movzbl %al,%edi /* zero-extend that into %edi */ |
| call __audit_syscall_exit |
| movl $(_TIF_ALLWORK_MASK & ~_TIF_SYSCALL_AUDIT),%edi |
| jmp sysret_check |
| #endif /* CONFIG_AUDITSYSCALL */ |
| |
| /* Do syscall tracing */ |
| tracesys: |
| leaq -REST_SKIP(%rsp), %rdi |
| movq $AUDIT_ARCH_X86_64, %rsi |
| call syscall_trace_enter_phase1 |
| test %rax, %rax |
| jnz tracesys_phase2 /* if needed, run the slow path */ |
| LOAD_ARGS 0 /* else restore clobbered regs */ |
| jmp system_call_fastpath /* and return to the fast path */ |
| |
| tracesys_phase2: |
| SAVE_REST |
| FIXUP_TOP_OF_STACK %rdi |
| movq %rsp, %rdi |
| movq $AUDIT_ARCH_X86_64, %rsi |
| movq %rax,%rdx |
| call syscall_trace_enter_phase2 |
| |
| /* |
| * Reload arg registers from stack in case ptrace changed them. |
| * We don't reload %rax because syscall_trace_entry_phase2() returned |
| * the value it wants us to use in the table lookup. |
| */ |
| LOAD_ARGS ARGOFFSET, 1 |
| RESTORE_REST |
| #if __SYSCALL_MASK == ~0 |
| cmpq $__NR_syscall_max,%rax |
| #else |
| andl $__SYSCALL_MASK,%eax |
| cmpl $__NR_syscall_max,%eax |
| #endif |
| ja int_ret_from_sys_call /* RAX(%rsp) is already set */ |
| 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. |
| */ |
| GLOBAL(int_ret_from_sys_call) |
| DISABLE_INTERRUPTS(CLBR_NONE) |
| TRACE_IRQS_OFF |
| movl $_TIF_ALLWORK_MASK,%edi |
| /* edi: mask to check */ |
| GLOBAL(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_cfi %rdi |
| SCHEDULE_USER |
| popq_cfi %rdi |
| 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) |
| int_check_syscall_exit_work: |
| SAVE_REST |
| /* Check for syscall exit trace */ |
| testl $_TIF_WORK_SYSCALL_EXIT,%edx |
| jz int_signal |
| pushq_cfi %rdi |
| leaq 8(%rsp),%rdi # &ptregs -> arg1 |
| call syscall_trace_leave |
| popq_cfi %rdi |
| 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) |
| |
| .macro FORK_LIKE func |
| ENTRY(stub_\func) |
| CFI_STARTPROC |
| popq %r11 /* save return address */ |
| PARTIAL_FRAME 0 |
| SAVE_REST |
| pushq %r11 /* put it back on stack */ |
| FIXUP_TOP_OF_STACK %r11, 8 |
| DEFAULT_FRAME 0 8 /* offset 8: return address */ |
| call sys_\func |
| RESTORE_TOP_OF_STACK %r11, 8 |
| ret $REST_SKIP /* pop extended registers */ |
| CFI_ENDPROC |
| END(stub_\func) |
| .endm |
| |
| .macro FIXED_FRAME label,func |
| ENTRY(\label) |
| CFI_STARTPROC |
| PARTIAL_FRAME 0 8 /* offset 8: return address */ |
| FIXUP_TOP_OF_STACK %r11, 8-ARGOFFSET |
| call \func |
| RESTORE_TOP_OF_STACK %r11, 8-ARGOFFSET |
| ret |
| CFI_ENDPROC |
| END(\label) |
| .endm |
| |
| FORK_LIKE clone |
| FORK_LIKE fork |
| FORK_LIKE vfork |
| FIXED_FRAME stub_iopl, sys_iopl |
| |
| 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 |
| addq $8, %rsp |
| PARTIAL_FRAME 0 |
| SAVE_REST |
| FIXUP_TOP_OF_STACK %r11 |
| call sys_execve |
| 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 |
| PARTIAL_FRAME 0 |
| SAVE_REST |
| 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) |
| |
| #ifdef CONFIG_X86_X32_ABI |
| ENTRY(stub_x32_rt_sigreturn) |
| CFI_STARTPROC |
| addq $8, %rsp |
| PARTIAL_FRAME 0 |
| SAVE_REST |
| FIXUP_TOP_OF_STACK %r11 |
| call sys32_x32_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_x32_rt_sigreturn) |
| |
| ENTRY(stub_x32_execve) |
| CFI_STARTPROC |
| addq $8, %rsp |
| PARTIAL_FRAME 0 |
| SAVE_REST |
| FIXUP_TOP_OF_STACK %r11 |
| call compat_sys_execve |
| RESTORE_TOP_OF_STACK %r11 |
| movq %rax,RAX(%rsp) |
| RESTORE_REST |
| jmp int_ret_from_sys_call |
| CFI_ENDPROC |
| END(stub_x32_execve) |
| |
| #endif |
| |
| /* |
| * 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) |
| .section .entry.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_cfi $(~vector+0x80) /* Note: always in signed byte range */ |
| .if ((vector-FIRST_EXTERNAL_VECTOR)%7) <> 6 |
| jmp 2f |
| .endif |
| .previous |
| .quad 1b |
| .section .entry.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 |
| /* reserve pt_regs for scratch regs and rbp */ |
| subq $ORIG_RAX-RBP, %rsp |
| CFI_ADJUST_CFA_OFFSET ORIG_RAX-RBP |
| SAVE_ARGS_IRQ |
| 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 |
| ASM_CLAC |
| addq $-0x80,(%rsp) /* Adjust vector to [-256,-1] range */ |
| interrupt do_IRQ |
| /* 0(%rsp): old_rsp-ARGOFFSET */ |
| ret_from_intr: |
| DISABLE_INTERRUPTS(CLBR_NONE) |
| TRACE_IRQS_OFF |
| decl PER_CPU_VAR(irq_count) |
| |
| /* Restore saved previous stack */ |
| popq %rsi |
| CFI_DEF_CFA rsi,SS+8-RBP /* reg/off reset after def_cfa_expr */ |
| leaq ARGOFFSET-RBP(%rsi), %rsp |
| CFI_DEF_CFA_REGISTER rsp |
| CFI_ADJUST_CFA_OFFSET RBP-ARGOFFSET |
| |
| 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 1,8,1 |
| |
| irq_return: |
| INTERRUPT_RETURN |
| |
| ENTRY(native_iret) |
| /* |
| * Are we returning to a stack segment from the LDT? Note: in |
| * 64-bit mode SS:RSP on the exception stack is always valid. |
| */ |
| #ifdef CONFIG_X86_ESPFIX64 |
| testb $4,(SS-RIP)(%rsp) |
| jnz native_irq_return_ldt |
| #endif |
| |
| .global native_irq_return_iret |
| native_irq_return_iret: |
| /* |
| * This may fault. Non-paranoid faults on return to userspace are |
| * handled by fixup_bad_iret. These include #SS, #GP, and #NP. |
| * Double-faults due to espfix64 are handled in do_double_fault. |
| * Other faults here are fatal. |
| */ |
| iretq |
| |
| #ifdef CONFIG_X86_ESPFIX64 |
| native_irq_return_ldt: |
| pushq_cfi %rax |
| pushq_cfi %rdi |
| SWAPGS |
| movq PER_CPU_VAR(espfix_waddr),%rdi |
| movq %rax,(0*8)(%rdi) /* RAX */ |
| movq (2*8)(%rsp),%rax /* RIP */ |
| movq %rax,(1*8)(%rdi) |
| movq (3*8)(%rsp),%rax /* CS */ |
| movq %rax,(2*8)(%rdi) |
| movq (4*8)(%rsp),%rax /* RFLAGS */ |
| movq %rax,(3*8)(%rdi) |
| movq (6*8)(%rsp),%rax /* SS */ |
| movq %rax,(5*8)(%rdi) |
| movq (5*8)(%rsp),%rax /* RSP */ |
| movq %rax,(4*8)(%rdi) |
| andl $0xffff0000,%eax |
| popq_cfi %rdi |
| orq PER_CPU_VAR(espfix_stack),%rax |
| SWAPGS |
| movq %rax,%rsp |
| popq_cfi %rax |
| jmp native_irq_return_iret |
| #endif |
| |
| /* 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_cfi %rdi |
| SCHEDULE_USER |
| popq_cfi %rdi |
| 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,PER_CPU_VAR(__preempt_count) |
| jnz 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 apicinterrupt3 num sym do_sym |
| ENTRY(\sym) |
| INTR_FRAME |
| ASM_CLAC |
| pushq_cfi $~(\num) |
| .Lcommon_\sym: |
| interrupt \do_sym |
| jmp ret_from_intr |
| CFI_ENDPROC |
| END(\sym) |
| .endm |
| |
| #ifdef CONFIG_TRACING |
| #define trace(sym) trace_##sym |
| #define smp_trace(sym) smp_trace_##sym |
| |
| .macro trace_apicinterrupt num sym |
| apicinterrupt3 \num trace(\sym) smp_trace(\sym) |
| .endm |
| #else |
| .macro trace_apicinterrupt num sym do_sym |
| .endm |
| #endif |
| |
| .macro apicinterrupt num sym do_sym |
| apicinterrupt3 \num \sym \do_sym |
| trace_apicinterrupt \num \sym |
| .endm |
| |
| #ifdef CONFIG_SMP |
| apicinterrupt3 IRQ_MOVE_CLEANUP_VECTOR \ |
| irq_move_cleanup_interrupt smp_irq_move_cleanup_interrupt |
| apicinterrupt3 REBOOT_VECTOR \ |
| reboot_interrupt smp_reboot_interrupt |
| #endif |
| |
| #ifdef CONFIG_X86_UV |
| apicinterrupt3 UV_BAU_MESSAGE \ |
| uv_bau_message_intr1 uv_bau_message_interrupt |
| #endif |
| apicinterrupt LOCAL_TIMER_VECTOR \ |
| apic_timer_interrupt smp_apic_timer_interrupt |
| apicinterrupt X86_PLATFORM_IPI_VECTOR \ |
| x86_platform_ipi smp_x86_platform_ipi |
| |
| #ifdef CONFIG_HAVE_KVM |
| apicinterrupt3 POSTED_INTR_VECTOR \ |
| kvm_posted_intr_ipi smp_kvm_posted_intr_ipi |
| #endif |
| |
| #ifdef CONFIG_X86_MCE_THRESHOLD |
| apicinterrupt THRESHOLD_APIC_VECTOR \ |
| threshold_interrupt smp_threshold_interrupt |
| #endif |
| |
| #ifdef CONFIG_X86_THERMAL_VECTOR |
| apicinterrupt THERMAL_APIC_VECTOR \ |
| thermal_interrupt smp_thermal_interrupt |
| #endif |
| |
| #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_IRQ_WORK |
| apicinterrupt IRQ_WORK_VECTOR \ |
| irq_work_interrupt smp_irq_work_interrupt |
| #endif |
| |
| /* |
| * Exception entry points. |
| */ |
| #define INIT_TSS_IST(x) PER_CPU_VAR(init_tss) + (TSS_ist + ((x) - 1) * 8) |
| |
| .macro idtentry sym do_sym has_error_code:req paranoid=0 shift_ist=-1 |
| ENTRY(\sym) |
| /* Sanity check */ |
| .if \shift_ist != -1 && \paranoid == 0 |
| .error "using shift_ist requires paranoid=1" |
| .endif |
| |
| .if \has_error_code |
| XCPT_FRAME |
| .else |
| INTR_FRAME |
| .endif |
| |
| ASM_CLAC |
| PARAVIRT_ADJUST_EXCEPTION_FRAME |
| |
| .ifeq \has_error_code |
| pushq_cfi $-1 /* ORIG_RAX: no syscall to restart */ |
| .endif |
| |
| subq $ORIG_RAX-R15, %rsp |
| CFI_ADJUST_CFA_OFFSET ORIG_RAX-R15 |
| |
| .if \paranoid |
| call save_paranoid |
| .else |
| call error_entry |
| .endif |
| |
| DEFAULT_FRAME 0 |
| |
| .if \paranoid |
| .if \shift_ist != -1 |
| TRACE_IRQS_OFF_DEBUG /* reload IDT in case of recursion */ |
| .else |
| TRACE_IRQS_OFF |
| .endif |
| .endif |
| |
| movq %rsp,%rdi /* pt_regs pointer */ |
| |
| .if \has_error_code |
| movq ORIG_RAX(%rsp),%rsi /* get error code */ |
| movq $-1,ORIG_RAX(%rsp) /* no syscall to restart */ |
| .else |
| xorl %esi,%esi /* no error code */ |
| .endif |
| |
| .if \shift_ist != -1 |
| subq $EXCEPTION_STKSZ, INIT_TSS_IST(\shift_ist) |
| .endif |
| |
| call \do_sym |
| |
| .if \shift_ist != -1 |
| addq $EXCEPTION_STKSZ, INIT_TSS_IST(\shift_ist) |
| .endif |
| |
| .if \paranoid |
| jmp paranoid_exit /* %ebx: no swapgs flag */ |
| .else |
| jmp error_exit /* %ebx: no swapgs flag */ |
| .endif |
| |
| CFI_ENDPROC |
| END(\sym) |
| .endm |
| |
| #ifdef CONFIG_TRACING |
| .macro trace_idtentry sym do_sym has_error_code:req |
| idtentry trace(\sym) trace(\do_sym) has_error_code=\has_error_code |
| idtentry \sym \do_sym has_error_code=\has_error_code |
| .endm |
| #else |
| .macro trace_idtentry sym do_sym has_error_code:req |
| idtentry \sym \do_sym has_error_code=\has_error_code |
| .endm |
| #endif |
| |
| idtentry divide_error do_divide_error has_error_code=0 |
| idtentry overflow do_overflow has_error_code=0 |
| idtentry bounds do_bounds has_error_code=0 |
| idtentry invalid_op do_invalid_op has_error_code=0 |
| idtentry device_not_available do_device_not_available has_error_code=0 |
| idtentry double_fault do_double_fault has_error_code=1 paranoid=1 |
| idtentry coprocessor_segment_overrun do_coprocessor_segment_overrun has_error_code=0 |
| idtentry invalid_TSS do_invalid_TSS has_error_code=1 |
| idtentry segment_not_present do_segment_not_present has_error_code=1 |
| idtentry spurious_interrupt_bug do_spurious_interrupt_bug has_error_code=0 |
| idtentry coprocessor_error do_coprocessor_error has_error_code=0 |
| idtentry alignment_check do_alignment_check has_error_code=1 |
| idtentry simd_coprocessor_error do_simd_coprocessor_error has_error_code=0 |
| |
| |
| /* Reload gs selector with exception handling */ |
| /* edi: new selector */ |
| ENTRY(native_load_gs_index) |
| CFI_STARTPROC |
| pushfq_cfi |
| DISABLE_INTERRUPTS(CLBR_ANY & ~CLBR_RDI) |
| SWAPGS |
| gs_change: |
| movl %edi,%gs |
| 2: mfence /* workaround */ |
| SWAPGS |
| popfq_cfi |
| ret |
| CFI_ENDPROC |
| END(native_load_gs_index) |
| |
| _ASM_EXTABLE(gs_change,bad_gs) |
| .section .fixup,"ax" |
| /* running with kernelgs */ |
| bad_gs: |
| SWAPGS /* switch back to user gs */ |
| xorl %eax,%eax |
| movl %eax,%gs |
| jmp 2b |
| .previous |
| |
| /* Call softirq on interrupt stack. Interrupts are off. */ |
| ENTRY(do_softirq_own_stack) |
| CFI_STARTPROC |
| pushq_cfi %rbp |
| CFI_REL_OFFSET rbp,0 |
| mov %rsp,%rbp |
| CFI_DEF_CFA_REGISTER rbp |
| incl PER_CPU_VAR(irq_count) |
| cmove PER_CPU_VAR(irq_stack_ptr),%rsp |
| push %rbp # backlink for old unwinder |
| call __do_softirq |
| leaveq |
| CFI_RESTORE rbp |
| CFI_DEF_CFA_REGISTER rsp |
| CFI_ADJUST_CFA_OFFSET -8 |
| decl PER_CPU_VAR(irq_count) |
| ret |
| CFI_ENDPROC |
| END(do_softirq_own_stack) |
| |
| #ifdef CONFIG_XEN |
| idtentry xen_hypervisor_callback xen_do_hypervisor_callback has_error_code=0 |
| |
| /* |
| * 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 PER_CPU_VAR(irq_count) |
| movq %rsp,%rbp |
| CFI_DEF_CFA_REGISTER rbp |
| cmovzq PER_CPU_VAR(irq_stack_ptr),%rsp |
| pushq %rbp # backlink for old unwinder |
| call xen_evtchn_do_upcall |
| popq %rsp |
| CFI_DEF_CFA_REGISTER rsp |
| decl PER_CPU_VAR(irq_count) |
| jmp error_exit |
| CFI_ENDPROC |
| END(xen_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 $-1 /* orig_ax = -1 => not a system call */ |
| SAVE_ALL |
| jmp error_exit |
| CFI_ENDPROC |
| END(xen_failsafe_callback) |
| |
| apicinterrupt3 HYPERVISOR_CALLBACK_VECTOR \ |
| xen_hvm_callback_vector xen_evtchn_do_upcall |
| |
| #endif /* CONFIG_XEN */ |
| |
| #if IS_ENABLED(CONFIG_HYPERV) |
| apicinterrupt3 HYPERVISOR_CALLBACK_VECTOR \ |
| hyperv_callback_vector hyperv_vector_handler |
| #endif /* CONFIG_HYPERV */ |
| |
| idtentry debug do_debug has_error_code=0 paranoid=1 shift_ist=DEBUG_STACK |
| idtentry int3 do_int3 has_error_code=0 paranoid=1 shift_ist=DEBUG_STACK |
| idtentry stack_segment do_stack_segment has_error_code=1 |
| #ifdef CONFIG_XEN |
| idtentry xen_debug do_debug has_error_code=0 |
| idtentry xen_int3 do_int3 has_error_code=0 |
| idtentry xen_stack_segment do_stack_segment has_error_code=1 |
| #endif |
| idtentry general_protection do_general_protection has_error_code=1 |
| trace_idtentry page_fault do_page_fault has_error_code=1 |
| #ifdef CONFIG_KVM_GUEST |
| idtentry async_page_fault do_async_page_fault has_error_code=1 |
| #endif |
| #ifdef CONFIG_X86_MCE |
| idtentry machine_check has_error_code=0 paranoid=1 do_sym=*machine_check_vector(%rip) |
| #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) |
| DEFAULT_FRAME |
| DISABLE_INTERRUPTS(CLBR_NONE) |
| TRACE_IRQS_OFF_DEBUG |
| testl %ebx,%ebx /* swapgs needed? */ |
| jnz paranoid_restore |
| testl $3,CS(%rsp) |
| jnz paranoid_userspace |
| paranoid_swapgs: |
| TRACE_IRQS_IRETQ 0 |
| SWAPGS_UNSAFE_STACK |
| RESTORE_ALL 8 |
| jmp irq_return |
| paranoid_restore: |
| TRACE_IRQS_IRETQ_DEBUG 0 |
| 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) |
| SCHEDULE_USER |
| 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 %rdi, RDI+8(%rsp) |
| movq %rsi, RSI+8(%rsp) |
| movq %rdx, RDX+8(%rsp) |
| movq %rcx, RCX+8(%rsp) |
| movq %rax, RAX+8(%rsp) |
| movq %r8, R8+8(%rsp) |
| movq %r9, R9+8(%rsp) |
| movq %r10, R10+8(%rsp) |
| movq %r11, R11+8(%rsp) |
| movq_cfi rbx, RBX+8 |
| movq %rbp, RBP+8(%rsp) |
| movq %r12, R12+8(%rsp) |
| movq %r13, R13+8(%rsp) |
| movq %r14, R14+8(%rsp) |
| movq %r15, R15+8(%rsp) |
| xorl %ebx,%ebx |
| testl $3,CS+8(%rsp) |
| je error_kernelspace |
| error_swapgs: |
| SWAPGS |
| error_sti: |
| TRACE_IRQS_OFF |
| ret |
| |
| /* |
| * There are two places in the kernel that can potentially fault with |
| * usergs. Handle them here. B stepping K8s sometimes report a |
| * truncated RIP for IRET exceptions returning to compat mode. Check |
| * for these here too. |
| */ |
| error_kernelspace: |
| CFI_REL_OFFSET rcx, RCX+8 |
| incl %ebx |
| leaq native_irq_return_iret(%rip),%rcx |
| cmpq %rcx,RIP+8(%rsp) |
| je error_bad_iret |
| movl %ecx,%eax /* zero extend */ |
| cmpq %rax,RIP+8(%rsp) |
| je bstep_iret |
| cmpq $gs_change,RIP+8(%rsp) |
| je error_swapgs |
| jmp error_sti |
| |
| bstep_iret: |
| /* Fix truncated RIP */ |
| movq %rcx,RIP+8(%rsp) |
| /* fall through */ |
| |
| error_bad_iret: |
| SWAPGS |
| mov %rsp,%rdi |
| call fixup_bad_iret |
| mov %rax,%rsp |
| decl %ebx /* Return to usergs */ |
| jmp error_sti |
| CFI_ENDPROC |
| 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) |
| |
| /* |
| * Test if a given stack is an NMI stack or not. |
| */ |
| .macro test_in_nmi reg stack nmi_ret normal_ret |
| cmpq %\reg, \stack |
| ja \normal_ret |
| subq $EXCEPTION_STKSZ, %\reg |
| cmpq %\reg, \stack |
| jb \normal_ret |
| jmp \nmi_ret |
| .endm |
| |
| /* runs on exception stack */ |
| ENTRY(nmi) |
| INTR_FRAME |
| PARAVIRT_ADJUST_EXCEPTION_FRAME |
| /* |
| * We allow breakpoints in NMIs. If a breakpoint occurs, then |
| * the iretq it performs will take us out of NMI context. |
| * This means that we can have nested NMIs where the next |
| * NMI is using the top of the stack of the previous NMI. We |
| * can't let it execute because the nested NMI will corrupt the |
| * stack of the previous NMI. NMI handlers are not re-entrant |
| * anyway. |
| * |
| * To handle this case we do the following: |
| * Check the a special location on the stack that contains |
| * a variable that is set when NMIs are executing. |
| * The interrupted task's stack is also checked to see if it |
| * is an NMI stack. |
| * If the variable is not set and the stack is not the NMI |
| * stack then: |
| * o Set the special variable on the stack |
| * o Copy the interrupt frame into a "saved" location on the stack |
| * o Copy the interrupt frame into a "copy" location on the stack |
| * o Continue processing the NMI |
| * If the variable is set or the previous stack is the NMI stack: |
| * o Modify the "copy" location to jump to the repeate_nmi |
| * o return back to the first NMI |
| * |
| * Now on exit of the first NMI, we first clear the stack variable |
| * The NMI stack will tell any nested NMIs at that point that it is |
| * nested. Then we pop the stack normally with iret, and if there was |
| * a nested NMI that updated the copy interrupt stack frame, a |
| * jump will be made to the repeat_nmi code that will handle the second |
| * NMI. |
| */ |
| |
| /* Use %rdx as out temp variable throughout */ |
| pushq_cfi %rdx |
| CFI_REL_OFFSET rdx, 0 |
| |
| /* |
| * If %cs was not the kernel segment, then the NMI triggered in user |
| * space, which means it is definitely not nested. |
| */ |
| cmpl $__KERNEL_CS, 16(%rsp) |
| jne first_nmi |
| |
| /* |
| * Check the special variable on the stack to see if NMIs are |
| * executing. |
| */ |
| cmpl $1, -8(%rsp) |
| je nested_nmi |
| |
| /* |
| * Now test if the previous stack was an NMI stack. |
| * We need the double check. We check the NMI stack to satisfy the |
| * race when the first NMI clears the variable before returning. |
| * We check the variable because the first NMI could be in a |
| * breakpoint routine using a breakpoint stack. |
| */ |
| lea 6*8(%rsp), %rdx |
| test_in_nmi rdx, 4*8(%rsp), nested_nmi, first_nmi |
| CFI_REMEMBER_STATE |
| |
| nested_nmi: |
| /* |
| * Do nothing if we interrupted the fixup in repeat_nmi. |
| * It's about to repeat the NMI handler, so we are fine |
| * with ignoring this one. |
| */ |
| movq $repeat_nmi, %rdx |
| cmpq 8(%rsp), %rdx |
| ja 1f |
| movq $end_repeat_nmi, %rdx |
| cmpq 8(%rsp), %rdx |
| ja nested_nmi_out |
| |
| 1: |
| /* Set up the interrupted NMIs stack to jump to repeat_nmi */ |
| leaq -1*8(%rsp), %rdx |
| movq %rdx, %rsp |
| CFI_ADJUST_CFA_OFFSET 1*8 |
| leaq -10*8(%rsp), %rdx |
| pushq_cfi $__KERNEL_DS |
| pushq_cfi %rdx |
| pushfq_cfi |
| pushq_cfi $__KERNEL_CS |
| pushq_cfi $repeat_nmi |
| |
| /* Put stack back */ |
| addq $(6*8), %rsp |
| CFI_ADJUST_CFA_OFFSET -6*8 |
| |
| nested_nmi_out: |
| popq_cfi %rdx |
| CFI_RESTORE rdx |
| |
| /* No need to check faults here */ |
| INTERRUPT_RETURN |
| |
| CFI_RESTORE_STATE |
| first_nmi: |
| /* |
| * Because nested NMIs will use the pushed location that we |
| * stored in rdx, we must keep that space available. |
| * Here's what our stack frame will look like: |
| * +-------------------------+ |
| * | original SS | |
| * | original Return RSP | |
| * | original RFLAGS | |
| * | original CS | |
| * | original RIP | |
| * +-------------------------+ |
| * | temp storage for rdx | |
| * +-------------------------+ |
| * | NMI executing variable | |
| * +-------------------------+ |
| * | copied SS | |
| * | copied Return RSP | |
| * | copied RFLAGS | |
| * | copied CS | |
| * | copied RIP | |
| * +-------------------------+ |
| * | Saved SS | |
| * | Saved Return RSP | |
| * | Saved RFLAGS | |
| * | Saved CS | |
| * | Saved RIP | |
| * +-------------------------+ |
| * | pt_regs | |
| * +-------------------------+ |
| * |
| * The saved stack frame is used to fix up the copied stack frame |
| * that a nested NMI may change to make the interrupted NMI iret jump |
| * to the repeat_nmi. The original stack frame and the temp storage |
| * is also used by nested NMIs and can not be trusted on exit. |
| */ |
| /* Do not pop rdx, nested NMIs will corrupt that part of the stack */ |
| movq (%rsp), %rdx |
| CFI_RESTORE rdx |
| |
| /* Set the NMI executing variable on the stack. */ |
| pushq_cfi $1 |
| |
| /* |
| * Leave room for the "copied" frame |
| */ |
| subq $(5*8), %rsp |
| CFI_ADJUST_CFA_OFFSET 5*8 |
| |
| /* Copy the stack frame to the Saved frame */ |
| .rept 5 |
| pushq_cfi 11*8(%rsp) |
| .endr |
| CFI_DEF_CFA_OFFSET SS+8-RIP |
| |
| /* Everything up to here is safe from nested NMIs */ |
| |
| /* |
| * If there was a nested NMI, the first NMI's iret will return |
| * here. But NMIs are still enabled and we can take another |
| * nested NMI. The nested NMI checks the interrupted RIP to see |
| * if it is between repeat_nmi and end_repeat_nmi, and if so |
| * it will just return, as we are about to repeat an NMI anyway. |
| * This makes it safe to copy to the stack frame that a nested |
| * NMI will update. |
| */ |
| repeat_nmi: |
| /* |
| * Update the stack variable to say we are still in NMI (the update |
| * is benign for the non-repeat case, where 1 was pushed just above |
| * to this very stack slot). |
| */ |
| movq $1, 10*8(%rsp) |
| |
| /* Make another copy, this one may be modified by nested NMIs */ |
| addq $(10*8), %rsp |
| CFI_ADJUST_CFA_OFFSET -10*8 |
| .rept 5 |
| pushq_cfi -6*8(%rsp) |
| .endr |
| subq $(5*8), %rsp |
| CFI_DEF_CFA_OFFSET SS+8-RIP |
| end_repeat_nmi: |
| |
| /* |
| * Everything below this point can be preempted by a nested |
| * NMI if the first NMI took an exception and reset our iret stack |
| * so that we repeat another NMI. |
| */ |
| pushq_cfi $-1 /* ORIG_RAX: no syscall to restart */ |
| subq $ORIG_RAX-R15, %rsp |
| CFI_ADJUST_CFA_OFFSET ORIG_RAX-R15 |
| /* |
| * Use save_paranoid to handle SWAPGS, but no need to use paranoid_exit |
| * as we should not be calling schedule in NMI context. |
| * Even with normal interrupts enabled. An NMI should not be |
| * setting NEED_RESCHED or anything that normal interrupts and |
| * exceptions might do. |
| */ |
| call save_paranoid |
| DEFAULT_FRAME 0 |
| |
| /* |
| * Save off the CR2 register. If we take a page fault in the NMI then |
| * it could corrupt the CR2 value. If the NMI preempts a page fault |
| * handler before it was able to read the CR2 register, and then the |
| * NMI itself takes a page fault, the page fault that was preempted |
| * will read the information from the NMI page fault and not the |
| * origin fault. Save it off and restore it if it changes. |
| * Use the r12 callee-saved register. |
| */ |
| movq %cr2, %r12 |
| |
| /* paranoidentry do_nmi, 0; without TRACE_IRQS_OFF */ |
| movq %rsp,%rdi |
| movq $-1,%rsi |
| call do_nmi |
| |
| /* Did the NMI take a page fault? Restore cr2 if it did */ |
| movq %cr2, %rcx |
| cmpq %rcx, %r12 |
| je 1f |
| movq %r12, %cr2 |
| 1: |
| |
| testl %ebx,%ebx /* swapgs needed? */ |
| jnz nmi_restore |
| nmi_swapgs: |
| SWAPGS_UNSAFE_STACK |
| nmi_restore: |
| /* Pop the extra iret frame at once */ |
| RESTORE_ALL 6*8 |
| |
| /* Clear the NMI executing stack variable */ |
| movq $0, 5*8(%rsp) |
| jmp irq_return |
| CFI_ENDPROC |
| END(nmi) |
| |
| ENTRY(ignore_sysret) |
| CFI_STARTPROC |
| mov $-ENOSYS,%eax |
| sysret |
| CFI_ENDPROC |
| END(ignore_sysret) |
| |
