Thu Oct 30 08:20:15 2014 UTC ()
config(1): More TODO


(uebayasi)
diff -r1.5 -r1.6 src/usr.bin/config/TODO
cvs diff -r1.5 -r1.6 src/usr.bin/config/TODO (expand / switch to unified diff)

--- src/usr.bin/config/TODO 2014/10/30 01:26:20 1.5
+++ src/usr.bin/config/TODO 2014/10/30 08:20:15 1.6
@@ -99,35 +99,54 @@ o Introduce "class". @@ -99,35 +99,54 @@ o Introduce "class".
99 99
100 For syntax clarity, class names could be used as a keyword to select the 100 For syntax clarity, class names could be used as a keyword to select the
101 class's instance module: 101 class's instance module:
102 102
103 # Define net80211 module as netproto class 103 # Define net80211 module as netproto class
104 class netproto 104 class netproto
105 define net80211: netproto 105 define net80211: netproto
106 106
107 # Select net80211 to be builtin 107 # Select net80211 to be builtin
108 netproto net80211 108 netproto net80211
109 109
110 Accordingly device/attach selection syntax should be revisited. 110 Accordingly device/attach selection syntax should be revisited.
111 111
112o Support kernel constructor/destructor (.ctors/.dtors) 112o Support kernel constructor/destructor (.kctors/.kdtors)
113 113
114 Initialization and finalization should be called via constructors and 114 Initialization and finalization should be called via constructors and
115 destructors. Don't hardcode those sequences as sys/kern/init_main.c:main() 115 destructors. Don't hardcode those sequences as sys/kern/init_main.c:main()
116 does. 116 does.
117 117
118 The order of .ctors/.dtors is resolved by dependency. The difference from 118 The order of .kctors/.kdtors is resolved by dependency. The difference from
119 userland is that in kernel depended ones are located in lower addresses; 119 userland is that in kernel depended ones are located in lower addresses;
120 "machdep" module is the lowest. Thus the lowest entry in .ctors must be 120 "machdep" module is the lowest. Thus the lowest entry in .ctors must be
121 executed the first. 121 executed the first.
122 122
 123 The .kctors/.kdtors entries are executed by kernel's main() function, unlike
 124 userland where start code executes .ctors/.dtors before main(). The hardcoded
 125 sequence of various subsystem initializations in init_main.c:main() will be
 126 replaced by an array of .kctors invocaions, and #ifdef's there will be gone.
 127
123o Replace linkset. 128o Replace linkset.
124 129
125 Don't allow kernel subsystems create random ELF sections (with potentially 130 Don't allow kernel subsystems create random ELF sections (with potentially
126 long names) in the final kernel. To collect some data in statically linked 131 long names) in the final kernel. To collect some data in statically linked
127 modules, creating intermediate sections (e.g. .data.linkset.sysctl) and 132 modules, creating intermediate sections (e.g. .data.linkset.sysctl) and
128 exporting the start/end symbols (e.g. _data_linkset_sysctl_{start,end}) 133 exporting the start/end symbols (e.g. _data_linkset_sysctl_{start,end})
129 using linker script should be fine. 134 using linker script should be fine.
130 135
131 Dynamically loaded modules have to register those entries via constructors 136 Dynamically loaded modules have to register those entries via constructors
132 (functions). This means that dynamically loaded modules are flexible but 137 (functions). This means that dynamically loaded modules are flexible but
133 come with overhead. 138 come with overhead.
 139
 140o Shared kernel objects.
 141
 142 Since NetBSD has not established a clear kernek ABI, every single kernel
 143 has to build all the objects by their own. As a result, similar kernels
 144 (e.g. evbarm kernels) repeatedly compile similar objects, that is waste of
 145 energy & space.
 146
 147 Share them if possible. For evb* ports, ideally everything except machdep.ko
 148 should be shared.
 149
 150 While leaving optimizations as options (CPU specific optimizations, inlined
 151 bus_space(9) operations, etc.) for users, the official binaries build
 152 provided by TNF should be as portable as possible.