feat(ebpf):[WIP] add eBPF support (#948)

* feat(kprobe): Add basic kprobe support for x86_64

* feat: add ebpf support (#912)

- 实现bpf()一部分命令，包括几种基本map，相关的helper函数
- 实现部分perf相关的数据结构
- 暂时为文件实现简单mmap
- 实现一个使用kprobe统计syscall 调用次数的ebpf程序

对eBPF支持程度(基本)：

- 简单的eBPF程序(没有指定特殊的Map)
- 使用内核已经实现的Map的eBPF程序
- 可以和kprobe配合使用
- 内核Map相关的接口定义已经实现，添加新的Map较为简单

不支持的功能:
- 区分不同的eBPF程序类型(Network/Cgroup)并限定可调用的helper函数集
- 与内核其它跟踪机制配合(tracepoint)
- 其它helper和Map


todo

- [ ]  修改mmap，需要讨论，因为这个和块缓存层相关
- [x]  添加文档
- [x]  修复可能的错误
- [x] 增加rbpf版本信息

* feat: add /sys/devices/system/cpu/possible file

* feat: add /sys/devices/system/cpu/online

kernel/crates/rbpf/mk/appveyor.bat

@@ -0,0 +1,72 @@
+echo on
+SetLocal EnableDelayedExpansion
+
+REM This is the recommended way to choose the toolchain version, according to
+REM Appveyor's documentation.
+SET PATH=C:\Program Files (x86)\MSBuild\%TOOLCHAIN_VERSION%\Bin;%PATH%
+
+set VCVARSALL="C:\Program Files (x86)\Microsoft Visual Studio %TOOLCHAIN_VERSION%\VC\vcvarsall.bat"
+
+if [%Platform%] NEQ [x64] goto win32
+set TARGET_ARCH=x86_64
+set TARGET_PROGRAM_FILES=%ProgramFiles%
+call %VCVARSALL% amd64
+if %ERRORLEVEL% NEQ 0 exit 1
+goto download
+
+:win32
+echo on
+if [%Platform%] NEQ [Win32] exit 1
+set TARGET_ARCH=i686
+set TARGET_PROGRAM_FILES=%ProgramFiles(x86)%
+call %VCVARSALL% amd64_x86
+if %ERRORLEVEL% NEQ 0 exit 1
+goto download
+
+:download
+REM vcvarsall turns echo off
+echo on
+
+mkdir windows_build_tools
+mkdir windows_build_tools\
+echo Downloading Yasm...
+powershell -Command "(New-Object Net.WebClient).DownloadFile('http://www.tortall.net/projects/yasm/releases/yasm-1.3.0-win64.exe', 'windows_build_tools\yasm.exe')"
+if %ERRORLEVEL% NEQ 0 (
+  echo ...downloading Yasm failed.
+  exit 1
+)
+
+set RUST_URL=https://static.rust-lang.org/dist/rust-%RUST%-%TARGET_ARCH%-pc-windows-msvc.msi
+echo Downloading %RUST_URL%...
+mkdir build
+powershell -Command "(New-Object Net.WebClient).DownloadFile('%RUST_URL%', 'build\rust-%RUST%-%TARGET_ARCH%-pc-windows-msvc.msi')"
+if %ERRORLEVEL% NEQ 0 (
+  echo ...downloading Rust failed.
+  exit 1
+)
+
+start /wait msiexec /i build\rust-%RUST%-%TARGET_ARCH%-pc-windows-msvc.msi INSTALLDIR="%TARGET_PROGRAM_FILES%\Rust %RUST%" /quiet /qn /norestart
+if %ERRORLEVEL% NEQ 0 exit 1
+
+set PATH="%TARGET_PROGRAM_FILES%\Rust %RUST%\bin";%cd%\windows_build_tools;%PATH%
+
+if [%Configuration%] == [Release] set CARGO_MODE=--release
+
+set
+
+link /?
+cl /?
+rustc --version
+cargo --version
+
+cargo test --all-features -vv %CARGO_MODE%
+if %ERRORLEVEL% NEQ 0 exit 1
+
+REM Verify that `cargo build`, independent from `cargo test`, works; i.e.
+REM verify that non-test builds aren't trying to use test-only features.
+cargo build -vv %CARGO_MODE%
+if %ERRORLEVEL% NEQ 0 exit 1
+
+REM Verify that we can build with all features
+cargo build --all-features -vv %CARGO_MODE%
+if %ERRORLEVEL% NEQ 0 exit 1