An upcoming change to Scudo will change how we use the TLS slot
in tsd_shared.h, which will be a little easier to deal with if
we can remove the code path that calls pthread_getspecific and
pthread_setspecific. The only known user of this code path is Fuchsia.
We can't eliminate this code path by making Fuchsia use ELF TLS
because although Fuchsia supports ELF TLS, it is not supported within
libc itself. To address this, Roland McGrath on the Fuchsia team has
proposed that Scudo will optionally call a platform-provided function
to access a TLS slot reserved for Scudo. Android also has a reserved
TLS slot, but the code that accesses the TLS slot lives in Scudo.
We can eliminate some complexity and duplicated code by having Android
use the same mechanism that was proposed for Fuchsia, which is what
this change does. A separate change to Android implements it.
Differential Revision: https://reviews.llvm.org/D87420
Android now allocates only 8 fixed TLS slots. Somehow we were getting away
with using a non-existent slot until now, but in some cases the TLS slots
were being placed at the end of a page, which led to a segfault at startup.
Differential Revision: https://reviews.llvm.org/D69191
llvm-svn: 375276
Summary:
The Secondary allocator wraps the platform allocation primitives. It is
meant to be used for larger sizes that the Primary can't fullfill, as
it will be slower, and sizes are multiple of the system page size.
This also changes some of the existing code, notably the opaque
platform data being passed to the platform specific functions: we can
shave a couple of syscalls on Fuchsia by storing additional data (this
addresses a TODO).
Reviewers: eugenis, vitalybuka, hctim, morehouse
Reviewed By: morehouse
Subscribers: mgorny, delcypher, jfb, #sanitizers, llvm-commits
Tags: #llvm, #sanitizers
Differential Revision: https://reviews.llvm.org/D60787
llvm-svn: 359097
Summary:
This CL adds the platform specific code for Fuchsia, Linux & Android,
as well as some tests related to those (more tests to come later).
While some of it is pretty much a straight port of the existing scudo &
sanitizer_common code, the memory mapping functions have been reworked
a bit to fit the limited usage scenario that Scudo has for them.
For Fuchsia, I can now track the Vmar/Vmo pair for memory mappings if
there is an intent to grow or decommit some mapping (that will be
useful for the Primary).
Reviewers: eugenis, vitalybuka, mcgrathr, phosek, flowerhack, morehouse, dmmoore415
Reviewed By: vitalybuka, morehouse
Subscribers: kcc, dvyukov, srhines, mgorny, delcypher, jfb, jdoerfert, #sanitizers, llvm-commits
Tags: #llvm, #sanitizers
Differential Revision: https://reviews.llvm.org/D58184
llvm-svn: 354895
Peter Collingbourne