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Add new patcher memory hooks #1495

Merged
merged 8 commits into from
Apr 14, 2016
Merged

Add new patcher memory hooks #1495

merged 8 commits into from
Apr 14, 2016

Commits on Apr 13, 2016

  1. opal/memory: add support for patch based memory hooks 

    This commit adds support for runtime binary patching. The support is
broken down into two parts: util/opal_patcher.[ch] which contains the
functionality for runtime patching of symbols, and mca/memory/patcher
which patches the various symbols needed to provide support for memory
hooks. This work is preliminary and is based off work donated by IBM.

The patcher code is disabled if dlopen is disabled.

Signed-off-by: Nathan Hjelm <[email protected]>
    @hjelmn
    hjelmn committed Apr 13, 2016
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  2. opal/memory: update component structure 

    This commit makes it possible to set relative priorities for
components. Before the addition of the patched component there was
only one component that would run on any system but that is no longer
the case. When determining which component to open each component's
query function is called and the one that returns the highest priority
is opened. The default priority of the patcher component is set
slightly higher than the old ptmalloc2/ummunotify component.

This commit fixes a long-standing break in the abstration of the
memory components. ompi_mpi_init.c was referencing the linux malloc
hook initilize function to ensure the hooks are initialized for
libmpi.so. The abstraction break has been fixed by adding a memory
base function that calls the open memory component's malloc hook init
function if it has one. The code is not yet complete but is intended
to support ptmalloc in 2.0.0. In that case the base function will
always call the ptmalloc hook init if exists.

Signed-off-by: Nathan Hjelm <[email protected]>
    @hjelmn
    hjelmn committed Apr 13, 2016
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  3. opal/patch: add call to check if binary patching is supported 

    Signed-off-by: Nathan Hjelm <[email protected]>
    @hjelmn
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  4. contrib/platform: don't disable dlopen 

    The --enable-static gives us what we want: statically linked components.

Signed-off-by: Nathan Hjelm <[email protected]>
    @hjelmn
    hjelmn committed Apr 13, 2016
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  5. opal: add code patcher framework 

    This commit adds a framework to abstract runtime code patching.
Components in the new framework can provide functions for either
patching a named function or a function pointer. The later
functionality is not being used but may provide a way to allow memory
hooks when dlopen functionality is disabled.

This commit adds two different flavors of code patching. The first is
provided by the overwrite component. This component overwrites the
first several instructions of the target function with code to jump to
the provided hook function. The hook is expected to provide the full
functionality of the hooked function.

The linux patcher component is based on the memory hooks in ucx. It
only works on linux and operates by overwriting function pointers in
the symbol table. In this case the hook is free to call the original
function using the function pointer returned by dlsym.

Both components restore the original functions when the patcher
framework closes.

Changes had to be made to support Power/PowerPC with the Linux
dynamic loader patcher. Some of the changes:

 - Move code necessary for powerpc/power support to the patcher
   base. The code is needed by both the overwrite and linux
   components.

 - Move patch structure down to base and move the patch list to
   mca_patcher_base_module_t. The structure has been modified to
   include a function pointer to the function that will unapply the
   patch. This allows the mixing of multiple different types of
   patches in the patch_list.

 - Update linux patching code to keep track of the matching between
   got entry and original (unpatched) address. This allows us to
   completely clean up the patch on finalize.

All patchers keep track of the changes they made so that they can be
reversed when the patcher framework is closed.

At this time there are bugs in the Linux dynamic loader patcher so
its priority is lower than the overwrite patcher.

Signed-off-by: Nathan Hjelm <[email protected]>
    @hjelmn
    hjelmn committed Apr 13, 2016
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  6. opal/memory: remove ptmalloc2 

    This commit removes the ptmalloc2 memory hooks. This is necessary in
order to support lazy registration of memory hooks. A feature that is
not supported by the ptmalloc hooks but is supported by the new
patcher hooks.

Signed-off-by: Nathan Hjelm <[email protected]>
    @hjelmn
    hjelmn committed Apr 13, 2016
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  7. memory/patcher: updates to memory hooks 

    This commit fixes bugs that can cause crashes and memory corruption
when the mremap hook is called. The problem occurs because of the
ellipses (...) in the mremap intercept function. The ellipses cover
the optional new_addr argument on Linux. This commit removes the
ellipses and adds an explicit 5th argument.

This commit also adds a hook for shmdt. The code only works on Linux
at the moment as it needs to read /proc/self/maps to determine the
size of the shared memory segment.

Additionally, this commit removes the mmap hook. There is no
apparent benefit for detecting mmap(..., PROT_NONE, ...) and it
seems to cause problems when threads are in use.

Signed-off-by: Nathan Hjelm <[email protected]>
    @hjelmn
    hjelmn committed Apr 13, 2016
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  8. opal/memory: move initialization to first rcache creation 

    Because of the removal of the linux memory component it is no longer
necessary to initialize the memory component in opal_init(). This
commit moves the initialization to the creation of the first rcache
component.

Signed-off-by: Nathan Hjelm <[email protected]>
    @hjelmn
    hjelmn committed Apr 13, 2016
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