122 lines
3.5 KiB
Go
122 lines
3.5 KiB
Go
// Copyright 2018 The gVisor Authors.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package ring0
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import (
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"syscall"
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"gvisor.dev/gvisor/pkg/sentry/usermem"
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)
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var (
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// UserspaceSize is the total size of userspace.
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UserspaceSize = uintptr(1) << (VirtualAddressBits() - 1)
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// MaximumUserAddress is the largest possible user address.
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MaximumUserAddress = (UserspaceSize - 1) & ^uintptr(usermem.PageSize-1)
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// KernelStartAddress is the starting kernel address.
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KernelStartAddress = ^uintptr(0) - (UserspaceSize - 1)
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)
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// Kernel is a global kernel object.
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//
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// This contains global state, shared by multiple CPUs.
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type Kernel struct {
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KernelArchState
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}
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// Hooks are hooks for kernel functions.
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type Hooks interface {
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// KernelSyscall is called for kernel system calls.
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//
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// Return from this call will restore registers and return to the kernel: the
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// registers must be modified directly.
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//
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// If this function is not provided, a kernel exception results in halt.
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//
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// This must be go:nosplit, as this will be on the interrupt stack.
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// Closures are permitted, as the pointer to the closure frame is not
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// passed on the stack.
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KernelSyscall()
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// KernelException handles an exception during kernel execution.
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//
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// Return from this call will restore registers and return to the kernel: the
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// registers must be modified directly.
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//
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// If this function is not provided, a kernel exception results in halt.
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//
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// This must be go:nosplit, as this will be on the interrupt stack.
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// Closures are permitted, as the pointer to the closure frame is not
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// passed on the stack.
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KernelException(Vector)
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}
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// CPU is the per-CPU struct.
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type CPU struct {
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// self is a self reference.
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//
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// This is always guaranteed to be at offset zero.
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self *CPU
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// kernel is reference to the kernel that this CPU was initialized
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// with. This reference is kept for garbage collection purposes: CPU
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// registers may refer to objects within the Kernel object that cannot
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// be safely freed.
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kernel *Kernel
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// CPUArchState is architecture-specific state.
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CPUArchState
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// registers is a set of registers; these may be used on kernel system
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// calls and exceptions via the Registers function.
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registers syscall.PtraceRegs
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// hooks are kernel hooks.
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hooks Hooks
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}
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// Registers returns a modifiable-copy of the kernel registers.
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//
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// This is explicitly safe to call during KernelException and KernelSyscall.
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//
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//go:nosplit
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func (c *CPU) Registers() *syscall.PtraceRegs {
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return &c.registers
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}
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// SwitchOpts are passed to the Switch function.
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type SwitchOpts struct {
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// Registers are the user register state.
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Registers *syscall.PtraceRegs
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// FloatingPointState is a byte pointer where floating point state is
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// saved and restored.
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FloatingPointState *byte
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// PageTables are the application page tables.
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PageTables *pagetables.PageTables
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// Flush indicates that a TLB flush should be forced on switch.
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Flush bool
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// FullRestore indicates that an iret-based restore should be used.
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FullRestore bool
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// SwitchArchOpts are architecture-specific options.
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SwitchArchOpts
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}
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