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This is a rough guide to porting Valgrind to a new architecture, or a new
operating system. It's quite preliminary, but should get you started.
[29-May-2005: the stuff about the locations of files is now badly out of
date. --njn]
Porting Valgrind to a new architecture
Note that this implies both a new architecture, and a new platform (ie. arch/OS
combination). Please add to this list if it is missing anything.
To begin:
- Create necessary subdirs (copy x86/ and x86-linux/ subdirs). Yes, even the
test subdirectories. (You should make arch-specific tests later to be
thorough!) Put in files for them, edit them for the new
architecture name.
- Update (use x86 and x86-linux as a guide).
Once it configures ok, get it to compile:
- Create the Vex guest state type, VexGuest<ARCH>State
- Copy all the arch-specific and platform-specific files into the new
directories, eg. from x86 and x86-linux. Files like (this list is not
Edit obvious things like the file headers, and the #ifdef __X86_TOOL_ARCH_H
guards, so they refer to the new architecture, rather than x86.
Comment all their contents out.
- Try compiling. When it falls over on missing functions/types/constants, just
uncomment and fix up the copied ones. Just use stubs that fail (immediately
and obviously! -- use the "I_die_here" macro) for functions and macros to get
things compiling.
For the kernel types, you'll have to copy the types from the kernel source.
Use a recent kernel source, please. Don't just pull in all the
corresponding types/macros that x86 provides, otherwise you might end up
providing more types/macros than the core actually needs; only pull in types
as the compiler asks for them. You'll need a lot of the types in
vki_arch_posixtypes.h early on.
You'll need to update the files if you add/remove files.
Once it compiles ok, get it to run:
- Try running. When it falls over on stub function/macros, implement them
properly. The syscall table and syscall wrappers will be painful; do them
individually, on demand.
- A lot of the arch-specific stuff has been abstracted out of the core, but
there undoubtedly remains some arch-specific stuff in there. Abstract it out
as necessary, updating the other archs appropriately.
- If it crashes without telling you why, use lots of diagnostic printfs (or
OINKs) to track down the exact location of the crash.
Once it runs ok:
- Add the arch to the tests/arch_test.c file so the reg test script will work.
(Don't forget to add it to all_archs[].) Likewise for and
- Ensure the regression tests work, and add some arch-specific tests to
none/tests directory.
- Add the relevant entries to (copy the x86 and x86-linux
Porting Valgrind to a new OS
Similarly to above, this implies both a new OS, and a new platform.
- Create necessary subdirs (copy linux/ and x86-linux/ subdirs).
- Update (use linux and x86-linux as a guide).
- Implement all the necessary OS-specific and platform-specific types,
functions, and macros... use the following as templates:
- You'll need to copy appropriate kernel types into vki*.h.
You'll have to ensure that everywhere that vki_*/VKI_* types and constants
are used, that they are suitable for your new OS, otherwise factor their
usage out somehow. This will be painful.
- In particular, you'll need to implement the VGA_(syscall_table). You may be
able to reuse some of the generic (eg. POSIX) syscall wrappers, if the types
match. Otherwise, you'll have to write your own new wrappers. Do this
incrementally, as system calls are hit, otherwise you'll go crazy.
- Probably lots more things; this list should be added to!