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Diffstat (limited to 'arch/x86/kernel/entry_64.S')
| -rw-r--r-- | arch/x86/kernel/entry_64.S | 1442 |
1 files changed, 0 insertions, 1442 deletions
diff --git a/arch/x86/kernel/entry_64.S b/arch/x86/kernel/entry_64.S deleted file mode 100644 index 4ad79e946f5a..000000000000 --- a/arch/x86/kernel/entry_64.S +++ /dev/null @@ -1,1442 +0,0 @@ -/* - * 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. - * - * A note on terminology: - * - iret frame: Architecture defined interrupt frame from SS to RIP - * at the top of the kernel process stack. - * - * Some macro usage: - * - ENTRY/END Define functions in the symbol table. - * - 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/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" - - -#ifdef CONFIG_PARAVIRT -ENTRY(native_usergs_sysret64) - swapgs - sysretq -ENDPROC(native_usergs_sysret64) -#endif /* CONFIG_PARAVIRT */ - - -.macro TRACE_IRQS_IRETQ -#ifdef CONFIG_TRACE_IRQFLAGS - bt $9,EFLAGS(%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 - bt $9,EFLAGS(%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 - -/* - * 64bit SYSCALL instruction entry. Up to 6 arguments in registers. - * - * 64bit SYSCALL saves rip to rcx, clears rflags.RF, then saves rflags to r11, - * then loads new ss, cs, and rip from previously programmed MSRs. - * rflags gets masked by a value from another MSR (so CLD and CLAC - * are not needed). SYSCALL does not save anything on the stack - * and does not change rsp. - * - * Registers on entry: - * rax system call number - * rcx return address - * r11 saved rflags (note: r11 is callee-clobbered register in C ABI) - * rdi arg0 - * rsi arg1 - * rdx arg2 - * r10 arg3 (needs to be moved to rcx to conform to C ABI) - * r8 arg4 - * r9 arg5 - * (note: r12-r15,rbp,rbx are callee-preserved in C ABI) - * - * Only called from user space. - * - * When user can change pt_regs->foo 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) - /* - * Interrupts are off on entry. - * We do not frame this tiny irq-off block with TRACE_IRQS_OFF/ON, - * it is too small to ever cause noticeable irq latency. - */ - 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(rsp_scratch) - movq PER_CPU_VAR(cpu_current_top_of_stack),%rsp - - /* Construct struct pt_regs on stack */ - pushq $__USER_DS /* pt_regs->ss */ - pushq PER_CPU_VAR(rsp_scratch) /* pt_regs->sp */ - /* - * Re-enable interrupts. - * We use 'rsp_scratch' as a scratch space, hence irq-off block above - * must execute atomically in the face of possible interrupt-driven - * task preemption. We must enable interrupts only after we're done - * with using rsp_scratch: - */ - ENABLE_INTERRUPTS(CLBR_NONE) - pushq %r11 /* pt_regs->flags */ - pushq $__USER_CS /* pt_regs->cs */ - pushq %rcx /* pt_regs->ip */ - pushq %rax /* pt_regs->orig_ax */ - pushq %rdi /* pt_regs->di */ - pushq %rsi /* pt_regs->si */ - pushq %rdx /* pt_regs->dx */ - pushq %rcx /* pt_regs->cx */ - pushq $-ENOSYS /* pt_regs->ax */ - pushq %r8 /* pt_regs->r8 */ - pushq %r9 /* pt_regs->r9 */ - pushq %r10 /* pt_regs->r10 */ - pushq %r11 /* pt_regs->r11 */ - sub $(6*8),%rsp /* pt_regs->bp,bx,r12-15 not saved */ - - testl $_TIF_WORK_SYSCALL_ENTRY, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS) - 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 1f /* return -ENOSYS (already in pt_regs->ax) */ - movq %r10,%rcx - call *sys_call_table(,%rax,8) - movq %rax,RAX(%rsp) -1: -/* - * Syscall return path ending with SYSRET (fast path). - * Has incompletely filled pt_regs. - */ - LOCKDEP_SYS_EXIT - /* - * We do not frame this tiny irq-off block with TRACE_IRQS_OFF/ON, - * it is too small to ever cause noticeable irq latency. - */ - DISABLE_INTERRUPTS(CLBR_NONE) - - /* - * We must check ti flags with interrupts (or at least preemption) - * off because we must *never* return to userspace without - * processing exit work that is enqueued if we're preempted here. - * In particular, returning to userspace with any of the one-shot - * flags (TIF_NOTIFY_RESUME, TIF_USER_RETURN_NOTIFY, etc) set is - * very bad. - */ - testl $_TIF_ALLWORK_MASK, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS) - jnz int_ret_from_sys_call_irqs_off /* Go to the slow path */ - - RESTORE_C_REGS_EXCEPT_RCX_R11 - movq RIP(%rsp),%rcx - movq EFLAGS(%rsp),%r11 - movq RSP(%rsp),%rsp - /* - * 64bit SYSRET restores rip from rcx, - * rflags from r11 (but RF and VM bits are forced to 0), - * cs and ss are loaded from MSRs. - * Restoration of rflags re-enables interrupts. - * - * NB: On AMD CPUs with the X86_BUG_SYSRET_SS_ATTRS bug, the ss - * descriptor is not reinitialized. This means that we should - * avoid SYSRET with SS == NULL, which could happen if we schedule, - * exit the kernel, and re-enter using an interrupt vector. (All - * interrupt entries on x86_64 set SS to NULL.) We prevent that - * from happening by reloading SS in __switch_to. (Actually - * detecting the failure in 64-bit userspace is tricky but can be - * done.) - */ - USERGS_SYSRET64 - - /* Do syscall entry tracing */ -tracesys: - movq %rsp, %rdi - movl $AUDIT_ARCH_X86_64, %esi - call syscall_trace_enter_phase1 - test %rax, %rax - jnz tracesys_phase2 /* if needed, run the slow path */ - RESTORE_C_REGS_EXCEPT_RAX /* else restore clobbered regs */ - movq ORIG_RAX(%rsp), %rax - jmp system_call_fastpath /* and return to the fast path */ - -tracesys_phase2: - SAVE_EXTRA_REGS - movq %rsp, %rdi - movl $AUDIT_ARCH_X86_64, %esi - movq %rax,%rdx - call syscall_trace_enter_phase2 - - /* - * Reload 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. - */ - RESTORE_C_REGS_EXCEPT_RAX - RESTORE_EXTRA_REGS -#if __SYSCALL_MASK == ~0 - cmpq $__NR_syscall_max,%rax -#else - andl $__SYSCALL_MASK,%eax - cmpl $__NR_syscall_max,%eax -#endif - ja 1f /* return -ENOSYS (already in pt_regs->ax) */ - movq %r10,%rcx /* fixup for C */ - call *sys_call_table(,%rax,8) - movq %rax,RAX(%rsp) -1: - /* Use IRET because user could have changed pt_regs->foo */ - -/* - * Syscall return path ending with IRET. - * Has correct iret frame. - */ -GLOBAL(int_ret_from_sys_call) - DISABLE_INTERRUPTS(CLBR_NONE) -int_ret_from_sys_call_irqs_off: /* jumps come here from the irqs-off SYSRET path */ - 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 syscall_return - - /* 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 - SCHEDULE_USER - popq %rdi - DISABLE_INTERRUPTS(CLBR_NONE) - TRACE_IRQS_OFF - jmp int_with_check - - /* handle signals and tracing -- both require a full pt_regs */ -int_very_careful: - TRACE_IRQS_ON - ENABLE_INTERRUPTS(CLBR_NONE) - SAVE_EXTRA_REGS - /* Check for syscall exit trace */ - testl $_TIF_WORK_SYSCALL_EXIT,%edx - jz int_signal - pushq %rdi - leaq 8(%rsp),%rdi # &ptregs -> arg1 - call syscall_trace_leave - popq %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_EXTRA_REGS - DISABLE_INTERRUPTS(CLBR_NONE) - TRACE_IRQS_OFF - jmp int_with_check - -syscall_return: - /* The IRETQ could re-enable interrupts: */ - DISABLE_INTERRUPTS(CLBR_ANY) - TRACE_IRQS_IRETQ - - /* - * Try to use SYSRET instead of IRET if we're returning to - * a completely clean 64-bit userspace context. - */ - movq RCX(%rsp),%rcx - movq RIP(%rsp),%r11 - cmpq %rcx,%r11 /* RCX == RIP */ - jne opportunistic_sysret_failed - - /* - * On Intel CPUs, SYSRET with non-canonical RCX/RIP will #GP - * in kernel space. This essentially lets the user take over - * the kernel, since userspace controls RSP. - * - * If width of "canonical tail" ever becomes variable, this will need - * to be updated to remain correct on both old and new CPUs. - */ - .ifne __VIRTUAL_MASK_SHIFT - 47 - .error "virtual address width changed -- SYSRET checks need update" - .endif - /* Change top 16 bits to be the sign-extension of 47th bit */ - shl $(64 - (__VIRTUAL_MASK_SHIFT+1)), %rcx - sar $(64 - (__VIRTUAL_MASK_SHIFT+1)), %rcx - /* If this changed %rcx, it was not canonical */ - cmpq %rcx, %r11 - jne opportunistic_sysret_failed - - cmpq $__USER_CS,CS(%rsp) /* CS must match SYSRET */ - jne opportunistic_sysret_failed - - movq R11(%rsp),%r11 - cmpq %r11,EFLAGS(%rsp) /* R11 == RFLAGS */ - jne opportunistic_sysret_failed - - /* - * SYSRET can't restore RF. SYSRET can restore TF, but unlike IRET, - * restoring TF results in a trap from userspace immediately after - * SYSRET. This would cause an infinite loop whenever #DB happens - * with register state that satisfies the opportunistic SYSRET - * conditions. For example, single-stepping this user code: - * - * movq $stuck_here,%rcx - * pushfq - * popq %r11 - * stuck_here: - * - * would never get past 'stuck_here'. - */ - testq $(X86_EFLAGS_RF|X86_EFLAGS_TF), %r11 - jnz opportunistic_sysret_failed - - /* nothing to check for RSP */ - - cmpq $__USER_DS,SS(%rsp) /* SS must match SYSRET */ - jne opportunistic_sysret_failed - - /* - * We win! This label is here just for ease of understanding - * perf profiles. Nothing jumps here. - */ -syscall_return_via_sysret: - /* rcx and r11 are already restored (see code above) */ - RESTORE_C_REGS_EXCEPT_RCX_R11 - movq RSP(%rsp),%rsp - USERGS_SYSRET64 - -opportunistic_sysret_failed: - SWAPGS - jmp restore_c_regs_and_iret -END(system_call) - - - .macro FORK_LIKE func -ENTRY(stub_\func) - SAVE_EXTRA_REGS 8 - jmp sys_\func -END(stub_\func) - .endm - - FORK_LIKE clone - FORK_LIKE fork - FORK_LIKE vfork - -ENTRY(stub_execve) - call sys_execve -return_from_execve: - testl %eax, %eax - jz 1f - /* exec failed, can use fast SYSRET code path in this case */ - ret -1: - /* must use IRET code path (pt_regs->cs may have changed) */ - addq $8, %rsp - ZERO_EXTRA_REGS - movq %rax,RAX(%rsp) - jmp int_ret_from_sys_call -END(stub_execve) -/* - * Remaining execve stubs are only 7 bytes long. - * ENTRY() often aligns to 16 bytes, which in this case has no benefits. - */ - .align 8 -GLOBAL(stub_execveat) - call sys_execveat - jmp return_from_execve -END(stub_execveat) - -#if defined(CONFIG_X86_X32_ABI) || defined(CONFIG_IA32_EMULATION) - .align 8 -GLOBAL(stub_x32_execve) -GLOBAL(stub32_execve) - call compat_sys_execve - jmp return_from_execve -END(stub32_execve) -END(stub_x32_execve) - .align 8 -GLOBAL(stub_x32_execveat) -GLOBAL(stub32_execveat) - call compat_sys_execveat - jmp return_from_execve -END(stub32_execveat) -END(stub_x32_execveat) -#endif - -/* - * 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) - /* - * SAVE_EXTRA_REGS result is not normally needed: - * sigreturn overwrites all pt_regs->GPREGS. - * But sigreturn can fail (!), and there is no easy way to detect that. - * To make sure RESTORE_EXTRA_REGS doesn't restore garbage on error, - * we SAVE_EXTRA_REGS here. - */ - SAVE_EXTRA_REGS 8 - call sys_rt_sigreturn -return_from_stub: - addq $8, %rsp - RESTORE_EXTRA_REGS - movq %rax,RAX(%rsp) - jmp int_ret_from_sys_call -END(stub_rt_sigreturn) - -#ifdef CONFIG_X86_X32_ABI -ENTRY(stub_x32_rt_sigreturn) - SAVE_EXTRA_REGS 8 - call sys32_x32_rt_sigreturn - jmp return_from_stub -END(stub_x32_rt_sigreturn) -#endif - -/* - * A newly forked process directly context switches into this address. - * - * rdi: prev task we switched from - */ -ENTRY(ret_from_fork) - - LOCK ; btr $TIF_FORK,TI_flags(%r8) - - pushq $0x0002 - popfq # reset kernel eflags - - call schedule_tail # rdi: 'prev' task parameter - - RESTORE_EXTRA_REGS - - testb $3, CS(%rsp) # from kernel_thread? - - /* - * By the time we get here, we have no idea whether our pt_regs, - * ti flags, and ti status came from the 64-bit SYSCALL fast path, - * the slow path, or one of the ia32entry paths. - * Use IRET code path to return, since it can safely handle - * all of the above. - */ - jnz int_ret_from_sys_call - - /* We came from kernel_thread */ - /* nb: we depend on RESTORE_EXTRA_REGS above */ - movq %rbp, %rdi - call *%rbx - movl $0, RAX(%rsp) - RESTORE_EXTRA_REGS - jmp int_ret_from_sys_call -END(ret_from_fork) - -/* - * Build the entry stubs with some assembler magic. - * We pack 1 stub into every 8-byte block. - */ - .align 8 -ENTRY(irq_entries_start) - vector=FIRST_EXTERNAL_VECTOR - .rept (FIRST_SYSTEM_VECTOR - FIRST_EXTERNAL_VECTOR) - pushq $(~vector+0x80) /* Note: always in signed byte range */ - vector=vector+1 - jmp common_interrupt - .align 8 - .endr -END(irq_entries_start) - -/* - * 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 - cld - /* - * Since nothing in interrupt handling code touches r12...r15 members - * of "struct pt_regs", and since interrupts can nest, we can save - * four stack slots and simultaneously provide - * an unwind-friendly stack layout by saving "truncated" pt_regs - * exactly up to rbp slot, without these members. - */ - ALLOC_PT_GPREGS_ON_STACK -RBP - SAVE_C_REGS -RBP - /* this goes to 0(%rsp) for unwinder, not for saving the value: */ - SAVE_EXTRA_REGS_RBP -RBP - - leaq -RBP(%rsp),%rdi /* arg1 for \func (pointer to pt_regs) */ - - testb $3, CS-RBP(%rsp) - jz 1f - SWAPGS -1: - /* - * Save previous stack pointer, optionally switch to interrupt stack. - * 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) - */ - movq %rsp, %rsi - incl PER_CPU_VAR(irq_count) - cmovzq PER_CPU_VAR(irq_stack_ptr),%rsp - pushq %rsi - /* We entered an interrupt context - irqs are off: */ - TRACE_IRQS_OFF - - 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: - ASM_CLAC - addq $-0x80,(%rsp) /* Adjust vector to [-256,-1] range */ - interrupt do_IRQ - /* 0(%rsp): old RSP */ -ret_from_intr: - DISABLE_INTERRUPTS(CLBR_NONE) - TRACE_IRQS_OFF - decl PER_CPU_VAR(irq_count) - - /* Restore saved previous stack */ - popq %rsi - /* return code expects complete pt_regs - adjust rsp accordingly: */ - leaq -RBP(%rsi),%rsp - - testb $3, CS(%rsp) - jz retint_kernel - /* Interrupt came from user space */ -retint_user: - GET_THREAD_INFO(%rcx) - /* - * %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 - 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_c_regs_and_iret - -/* Returning to kernel space */ -retint_kernel: -#ifdef CONFIG_PREEMPT - /* Interrupts are off */ - /* Check if we need preemption */ - bt $9,EFLAGS(%rsp) /* interrupts were off? */ - jnc 1f -0: cmpl $0,PER_CPU_VAR(__preempt_count) - jnz 1f - call preempt_schedule_irq - jmp 0b -1: -#endif - /* - * The iretq could re-enable interrupts: - */ - TRACE_IRQS_IRETQ - -/* - * At this label, code paths which return to kernel and to user, - * which come from interrupts/exception and from syscalls, merge. - */ -restore_c_regs_and_iret: - RESTORE_C_REGS - REMOVE_PT_GPREGS_FROM_STACK 8 - -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 %rax - pushq %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 %rdi - orq PER_CPU_VAR(espfix_stack),%rax - SWAPGS - movq %rax,%rsp - popq %rax - jmp native_irq_return_iret -#endif - - /* edi: workmask, edx: work */ -retint_careful: - bt $TIF_NEED_RESCHED,%edx - jnc retint_signal - TRACE_IRQS_ON - ENABLE_INTERRUPTS(CLBR_NONE) - pushq %rdi - SCHEDULE_USER - popq %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_EXTRA_REGS - movq $-1,ORIG_RAX(%rsp) - xorl %esi,%esi # oldset - movq %rsp,%rdi # &pt_regs - call do_notify_resume - RESTORE_EXTRA_REGS - DISABLE_INTERRUPTS(CLBR_NONE) - TRACE_IRQS_OFF - GET_THREAD_INFO(%rcx) - jmp retint_with_reschedule - -END(common_interrupt) - -/* - * APIC interrupts. - */ -.macro apicinterrupt3 num sym do_sym -ENTRY(\sym) - ASM_CLAC - pushq $~(\num) -.Lcommon_\sym: - interrupt \do_sym - jmp ret_from_intr -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 CPU_TSS_IST(x) PER_CPU_VAR(cpu_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 - - ASM_CLAC - PARAVIRT_ADJUST_EXCEPTION_FRAME - - .ifeq \has_error_code - pushq $-1 /* ORIG_RAX: no syscall to restart */ - .endif - - ALLOC_PT_GPREGS_ON_STACK - - .if \paranoid - .if \paranoid == 1 - testb $3, CS(%rsp) /* If coming from userspace, switch */ - jnz 1f /* stacks. */ - .endif - call paranoid_entry - .else - call error_entry - .endif - /* returned flag: ebx=0: need swapgs on exit, ebx=1: don't need it */ - - .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, CPU_TSS_IST(\shift_ist) - .endif - - call \do_sym - - .if \shift_ist != -1 - addq $EXCEPTION_STKSZ, CPU_TSS_IST(\shift_ist) - .endif - - /* these procedures expect "no swapgs" flag in ebx */ - .if \paranoid - jmp paranoid_exit - .else - jmp error_exit - .endif - - .if \paranoid == 1 - /* - * Paranoid entry from userspace. Switch stacks and treat it - * as a normal entry. This means that paranoid handlers - * run in real process context if user_mode(regs). - */ -1: - call error_entry - - - movq %rsp,%rdi /* pt_regs pointer */ - call sync_regs - movq %rax,%rsp /* switch stack */ - - 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 - - call \do_sym - - jmp error_exit /* %ebx: no swapgs flag */ - .endif -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=2 -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) - pushfq - DISABLE_INTERRUPTS(CLBR_ANY & ~CLBR_RDI) - SWAPGS -gs_change: - movl %edi,%gs -2: mfence /* workaround */ - SWAPGS - popfq - ret -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) - pushq %rbp - mov %rsp,%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 - decl PER_CPU_VAR(irq_count) - ret -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) -/* - * 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 -11: incl PER_CPU_VAR(irq_count) - movq %rsp,%rbp - cmovzq PER_CPU_VAR(irq_stack_ptr),%rsp - pushq %rbp # backlink for old unwinder - call xen_evtchn_do_upcall - popq %rsp - decl PER_CPU_VAR(irq_count) -#ifndef CONFIG_PREEMPT - call xen_maybe_preempt_hcall -#endif - jmp error_exit -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) - movl %ds,%ecx - cmpw %cx,0x10(%rsp) - jne 1f - movl %es,%ecx - cmpw %cx,0x18(%rsp) - jne 1f - movl %fs,%ecx - cmpw %cx,0x20(%rsp) - jne 1f - movl %gs,%ecx - cmpw %cx,0x28(%rsp) - jne 1f - /* All segments match their saved values => Category 2 (Bad IRET). */ - movq (%rsp),%rcx - movq 8(%rsp),%r11 - addq $0x30,%rsp - pushq $0 /* RIP */ - pushq %r11 - pushq %rcx - jmp general_protection -1: /* Segment mismatch => Category 1 (Bad segment). Retry the IRET. */ - movq (%rsp),%rcx - movq 8(%rsp),%r11 - addq $0x30,%rsp - pushq $-1 /* orig_ax = -1 => not a system call */ - ALLOC_PT_GPREGS_ON_STACK - SAVE_C_REGS - SAVE_EXTRA_REGS - jmp error_exit -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 - -/* - * Save all registers in pt_regs, and switch gs if needed. - * Use slow, but surefire "are we in kernel?" check. - * Return: ebx=0: need swapgs on exit, ebx=1: otherwise - */ -ENTRY(paranoid_entry) - cld - SAVE_C_REGS 8 - SAVE_EXTRA_REGS 8 - movl $1,%ebx - movl $MSR_GS_BASE,%ecx - rdmsr - testl %edx,%edx - js 1f /* negative -> in kernel */ - SWAPGS - xorl %ebx,%ebx -1: ret -END(paranoid_entry) - -/* - * "Paranoid" exit path from exception stack. This is invoked - * only on return from non-NMI IST interrupts that came - * from kernel space. - * - * We may be returning to very strange contexts (e.g. very early - * in syscall entry), so checking for preemption here would - * be complicated. Fortunately, we there's no good reason - * to try to handle preemption here. - */ -/* On entry, ebx is "no swapgs" flag (1: don't need swapgs, 0: need it) */ -ENTRY(paranoid_exit) - DISABLE_INTERRUPTS(CLBR_NONE) - TRACE_IRQS_OFF_DEBUG - testl %ebx,%ebx /* swapgs needed? */ - jnz paranoid_exit_no_swapgs - TRACE_IRQS_IRETQ - SWAPGS_UNSAFE_STACK - jmp paranoid_exit_restore -paranoid_exit_no_swapgs: - TRACE_IRQS_IRETQ_DEBUG -paranoid_exit_restore: - RESTORE_EXTRA_REGS - RESTORE_C_REGS - REMOVE_PT_GPREGS_FROM_STACK 8 - INTERRUPT_RETURN -END(paranoid_exit) - -/* - * Save all registers in pt_regs, and switch gs if needed. - * Return: ebx=0: need swapgs on exit, ebx=1: otherwise - */ -ENTRY(error_entry) - cld - SAVE_C_REGS 8 - SAVE_EXTRA_REGS 8 - xorl %ebx,%ebx - testb $3, CS+8(%rsp) - jz 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: - 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 -END(error_entry) - - -/* On entry, ebx is "no swapgs" flag (1: don't need swapgs, 0: need it) */ -ENTRY(error_exit) - movl %ebx,%eax - RESTORE_EXTRA_REGS - DISABLE_INTERRUPTS(CLBR_NONE) - TRACE_IRQS_OFF - testl %eax,%eax - jnz retint_kernel - jmp retint_user -END(error_exit) - -/* Runs on exception stack */ -ENTRY(nmi) - 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 our temp variable throughout */ - pushq %rdx - - /* - * 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 - /* Compare the NMI stack (rdx) with the stack we came from (4*8(%rsp)) */ - cmpq %rdx, 4*8(%rsp) - /* If the stack pointer is above the NMI stack, this is a normal NMI */ - ja first_nmi - subq $EXCEPTION_STKSZ, %rdx - cmpq %rdx, 4*8(%rsp) - /* If it is below the NMI stack, it is a normal NMI */ - jb first_nmi - /* Ah, it is within the NMI stack, treat it as nested */ - -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 - leaq -10*8(%rsp), %rdx - pushq $__KERNEL_DS - pushq %rdx - pushfq - pushq $__KERNEL_CS - pushq $repeat_nmi - - /* Put stack back */ - addq $(6*8), %rsp - -nested_nmi_out: - popq %rdx - - /* No need to check faults here */ - INTERRUPT_RETURN - -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 - - /* Set the NMI executing variable on the stack. */ - pushq $1 - - /* - * Leave room for the "copied" frame - */ - subq $(5*8), %rsp - - /* Copy the stack frame to the Saved frame */ - .rept 5 - pushq 11*8(%rsp) - .endr - - /* 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 - .rept 5 - pushq -6*8(%rsp) - .endr - subq $(5*8), %rsp -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 $-1 /* ORIG_RAX: no syscall to restart */ - ALLOC_PT_GPREGS_ON_STACK - - /* - * Use paranoid_entry 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 paranoid_entry - - /* - * 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: - RESTORE_EXTRA_REGS - RESTORE_C_REGS - /* Pop the extra iret frame at once */ - REMOVE_PT_GPREGS_FROM_STACK 6*8 - - /* Clear the NMI executing stack variable */ - movq $0, 5*8(%rsp) - jmp irq_return -END(nmi) - -ENTRY(ignore_sysret) - mov $-ENOSYS,%eax - sysret -END(ignore_sysret) - |