The Design and Implementation of the Anykernel and Rump Kernels

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136 3.8.4 Rump Component Init Routines In the previous section we discussed the attachment of drivers that followed the kernel module framework. Now we discuss the runtime attachment of drivers that have not yet been converted to a kernel module, or code that applies to a only rump kernel environment. If a driver is modular, the module’s init routine should be preferred over any rump kernel specific routines since the module framework is more generic. However, a module’s init routine is not always enough for a rump kernel. Consider the following cases. On a regular system, parts of the kernel are configured by userspace utilities. For example, the Internet address of the loopback interface (127.0.0.1) is configured by the rc scripts instead of by the kernel. Another example is the creation of device nodes on the file system under the directory /dev. NetBSDdoes not have a dynamic device file system and device nodes are pre-created with the MAKEDEV script. Since a rump kernel does not have an associated userland or a persistent root file system, these configuration actions must be performed by the rump kernel itself. A rump component init routine may be created to augment the module init routine. By convention, we place the rump component init routines in the component’s source directory in a file called component.c. To define an init routine, the component should use the RUMP_COMPONENT() macro. The use of this macro serves the same purpose as the MODULE() macro and ensures that the init routine is automatically called during rump kernel bootstrap. The implementation places a descriptor structure in a .rodata section called rump_components. The RUMP_COMPONENT() macro takes as arguments a single parameter indicating when the component should be initialized with respect to other components. This specifier is required because of interdependencies of components that the NetBSD
137 level RUMP_COMPONENT_KERN RUMP_COMPONENT_VFS RUMP_COMPONENT_NET RUMP_COMPONENT_NET_ROUTE RUMP_COMPONENT_NET_IF RUMP_COMPONENT_NET_IFCFG RUMP_COMPONENT_DEV RUMP_COMPONENT_KERN_VFS purpose base initialization which is done before any factions are attached VFS components basic networking, attaching of networking domains routing, can be done only after all domains have attached interface creation (e.g. lo0) interface configuration, must be done after interfaces are created device components base initialization which is done after the VFS faction has attached, e.g. base components which do VFS operations Table 3.4: Rump component classes. The RUMP_COMPONENT facility allows to specify component initialization at rump kernel bootstrap time. Due to interdependencies between subsystems, the component type specifies the order in which components are initialized. The order of component initialization is from top to bottom. kernel code imposes. For example, the networking domains must be attached before interfaces can be configured. It is legal (and sometimes necessary) for components to define several init routines with different configuration times. We found it necessary to define eight different levels. They are presented in Table 3.4 in order of runtime initialization. Notably, the multitude of networking-related initialization levels conveys the current status of the NetBSD TCP/IP stack: it is not yet modular — a modular TCP/IP stack would encode the cross-dependencies in the drivers themselves.
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Department of Computer Science and
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9 Preface Meet the new boss Same as
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11 Then there is my dear Xi, who, s
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14 2.3.3 InterruptsandPreemption...
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16 4.1.1 Implementation Effort ....
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18 Appendix C Patches to the 5.99.4
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20 ISA LGPL LRU LWP MD MI MMU NIC O
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23 List of Figures 2.1 Rumpkernelhi
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25 4.14 Time to execute 5M system c
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29 1 Introduction In its classic ro
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31 and application-level drivers. T
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33 We define an anykernel to be an
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35 Our implementation supports rump
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37 The project was done in small in
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39 2 The Anykernel and Rump Kernels
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41 building on top of the entities
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43 Drivers in a rump kernel remain
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45 Figure 2.1: Rump k
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47 in Section 3.2.3. Whenever discu
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49 int rumpns_bpfopen(dev_t, int, i
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51 Figure 2.4:
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53 while the application logic stil
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55 We must solve the lack of a rump
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57 2.3.1 Kernel threads Up until no
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59 void * pool_cache_get_paddr(pool
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61 2.3.4 An Example We present an e
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63 Figure 2.6: Prov
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65 The straightforward use of exist
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68 We identified three obstacles fo
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70 for loadable kernel modules (dis
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72 e.g. the routine for mapping a p
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74 3.2.1 C Symbol Namespaces In the
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76 the double underscore namespace
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78 since the representation might n
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80 The following rumpuser interface
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82 The entry point rump_schedule()
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84 3.3.1 CPU Scheduling Recall from
Page 88 and 89: 86 The fastpath is taken in cases w
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Page 98 and 99: 96 in. Therefore, we should critica
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Page 104 and 105: 102 Since all pages managed by the
Page 106 and 107: 104 not in control of thread schedu
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Page 110 and 111: 108 /* * Run a cross call to cycle
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Page 114 and 115: 112 The kernel with uniprocessor lo
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Page 118 and 119: 116 The same wrapper works both for
Page 120 and 121: 118 5. Some calling conventions (e.
Page 122 and 123: 120 int rump_pub_lwproc_rfork(int a
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Page 126 and 127: 124 ule directory tree from /stand
Page 128 and 129: 126 After these steps have been per
Page 130 and 131: 128 Host Dynamic Linker Using the h
Page 132 and 133: 130 for (i = 0; i < SYS_NSYSENT; i+
Page 134 and 135: 132 into a rump kernel and the driv
Page 136 and 137: 134 sys/arch/x86/include/cpu.h: #de
Page 140 and 141: 138 RUMP_COMPONENT(RUMP_COMPONENT_N
Page 142 and 143: 140 We have three distinct cases we
Page 144 and 145: 142 # ifconfig tap0 create # ifconf
Page 146 and 147: 144 Unprivileged use of host’s ne
Page 148 and 149: 146 DOMAIN_DEFINE(sockindomain); co
Page 150 and 151: 148 issue another write before the
Page 152 and 153: 150 using an interface called USBDI
Page 154 and 155: 152 The kernel device configuration
Page 156 and 157: 154 # $NetBSD: UMASS.ioconf,v 1.4 2
Page 158 and 159: 156 USB Host Controller Hub0 (root)
Page 160 and 161: 158 Figure 3.30: File s
Page 162 and 163: 160 in-kernel mount: /dev/sd0e /m/u
Page 164 and 165: 162 structure being created by rump
Page 166 and 167: 164 3.12.1 Client-Kernel Locators B
Page 168 and 169: 166 A tmpfs server listening on INA
Page 170 and 171: 168 Request Arguments Response Desc
Page 172 and 173: 170 Host syscall rump syscall 1. op
Page 174 and 175: 172 A client’s initial connection
Page 176 and 177: 174 their system calls to a rump ke
Page 178 and 179: 176 stdin/stdout, the new file desc
Page 180 and 181: 178 Supporting fork() Recall, the f
Page 182 and 183: 180 As with fork, most of the kerne
Page 184 and 185: 182 Anecdotal analysis For several
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186 SLOC 8000 7000 6000 5000 4000 3
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188 Total commits to the kernel 9,6
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190 120 build time (minutes) 100 80
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192 4.2.2 makefs For a source tree
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194 not include later debugging [76
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196 the necessary tools such as mak
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198 proach of supplying alternate c
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200 are not out-of-the-box compatib
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202 golem> mount -t msdos -o rump /
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204 Full OS By a full OS we mean a
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206 • Rapid prototyping: One of t
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208 4.5.3 Testing: Case Studies We
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210 static void scsitest_request(st
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212 waits for the timeout and check
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214 • We noticed that even in sup
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216 which were discovered during wr
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218 version swap no swap NetBSD 5.1
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220 It needs to be stressed that Ta
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222 Network clusters Bootstrapping
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224 8 7 Standard components Self-co
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226 Rump kernel calls, as expected,
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228 Traditional FFS We measure the
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230 80 70 60 seconds 50 40 30 20 10
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232 The results are presented in Fi
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234 behavior is required by the act
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236
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238 Rialto [29] is an operating sys
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240 One argument for partitioned op
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242 View OS The View OS [37] approa
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244 OSKit Instead of making system
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246 discussing the type incompatibi
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248 difference to the abovementione
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250 At runtime, a rump kernel can a
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252 For testing and development we
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254
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256 Art of Virtualization. In: Proc
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258 [30] Adam Dunkels. 2001. Design
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260 [47] Galen C. Hunt and James R.
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262 [67] Steven McCanne and Van Jac
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264 [87] NetBSD Project. URL http:/
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266 of the 6th Workshop on Programm
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268
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A-2 RUMP.DHCPCLIENT(1) NetBSD Gener
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A-4 RUMP.HALT(1) NetBSD General Com
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A-6 RUMP_SERVER(1) NetBSD General C
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A-8 RUMP_SERVER(1) NetBSD General C
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A-10 SHMIF_DUMPBUS(1) NetBSD Genera
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A-12 P2K(3) NetBSD Library Function
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A-14 P2K(3) NetBSD Library Function
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A-16 RUMP(3) NetBSD Library Functio
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A-18 RUMP(3) NetBSD Library Functio
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A-20 RUMP_ETFS(3) NetBSD Library Fu
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A-22 RUMP_ETFS(3) NetBSD Library Fu
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A-24 RUMP_LWPROC(3) NetBSD Library
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A-26 RUMP_LWPROC(3) NetBSD Library
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A-28 RUMPCLIENT(3) NetBSD Library F
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A-30 RUMPCLIENT(3) NetBSD Library F
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A-32 RUMPHIJACK(3) NetBSD Library F
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A-38 UKFS(3) NetBSD Library Functio
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A-48 SHMIF(4) NetBSD Kernel Interfa
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A-50 RUMP_SP(7) NetBSD Miscellaneou
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A-52 RUMP_SP(7) NetBSD Miscellaneou
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B-2 TCP connections use standard TC
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B-4 rump clients. This means that j
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B-6 ponents. That can be done simpl
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B-8 Our goal is to add another part
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B-10 golem> export RUMP_SERVER=unix
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B-12 golem> rump.dd if=/dev/rcgd0d
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B-14 demogorgon# cgdconfig cgd0 /de
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B-16 rump_server -lrumpnet -lrumpne
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B-18 golem> rump.ifconfig virt0 cre
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B-20 Congratulations, that’s it.
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B-22 purely in userspace, it does n
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B-24 We then proceed to create a mo
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B-26 Then, the only thing left is t
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B-28 -d key=/dk,hostpath=${NFSX}/ff
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B-30 configuration. golem> sh rumpn
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B-32
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C-2 This is a quick fix for making
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C-4 This fixes the conditionally co
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Aalto-DD 171/2012 9HSTFMG*aejbgi+ I
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