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| author | Florian Weimer <fweimer@redhat.com> | 2021-12-28 22:52:56 +0100 |
|---|---|---|
| committer | Florian Weimer <fweimer@redhat.com> | 2021-12-28 22:52:56 +0100 |
| commit | 5d28a8962dcb6ec056b81d730e3c6fb57185a210 (patch) | |
| tree | 3d714aaef575deba322fa5a1e29c76c6f96dc850 /include | |
| parent | 83b8d5027d2f80c4603cd706da95d6c9a09a4e16 (diff) | |
| download | glibc-5d28a8962dcb6ec056b81d730e3c6fb57185a210.zip glibc-5d28a8962dcb6ec056b81d730e3c6fb57185a210.tar.gz glibc-5d28a8962dcb6ec056b81d730e3c6fb57185a210.tar.bz2 | |
elf: Add _dl_find_object function
It can be used to speed up the libgcc unwinder, and the internal
_dl_find_dso_for_object function (which is used for caller
identification in dlopen and related functions, and in dladdr).
_dl_find_object is in the internal namespace due to bug 28503.
If libgcc switches to _dl_find_object, this namespace issue will
be fixed. It is located in libc for two reasons: it is necessary
to forward the call to the static libc after static dlopen, and
there is a link ordering issue with -static-libgcc and libgcc_eh.a
because libc.so is not a linker script that includes ld.so in the
glibc build tree (so that GCC's internal -lc after libgcc_eh.a does
not pick up ld.so).
It is necessary to do the i386 customization in the
sysdeps/x86/bits/dl_find_object.h header shared with x86-64 because
otherwise, multilib installations are broken.
The implementation uses software transactional memory, as suggested
by Torvald Riegel. Two copies of the supporting data structures are
used, also achieving full async-signal-safety.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/atomic_wide_counter.h | 14 | ||||
| -rw-r--r-- | include/bits/dl_find_object.h | 1 | ||||
| -rw-r--r-- | include/dlfcn.h | 2 | ||||
| -rw-r--r-- | include/link.h | 3 |
4 files changed, 20 insertions, 0 deletions
diff --git a/include/atomic_wide_counter.h b/include/atomic_wide_counter.h index 31f009d..d1c40cd 100644 --- a/include/atomic_wide_counter.h +++ b/include/atomic_wide_counter.h @@ -31,6 +31,12 @@ __atomic_wide_counter_load_relaxed (__atomic_wide_counter *c) } static inline uint64_t +__atomic_wide_counter_load_acquire (__atomic_wide_counter *c) +{ + return atomic_load_acquire (&c->__value64); +} + +static inline uint64_t __atomic_wide_counter_fetch_add_relaxed (__atomic_wide_counter *c, unsigned int val) { @@ -64,6 +70,14 @@ __atomic_wide_counter_fetch_xor_release (__atomic_wide_counter *c, uint64_t __atomic_wide_counter_load_relaxed (__atomic_wide_counter *c) attribute_hidden; +static inline uint64_t +__atomic_wide_counter_load_acquire (__atomic_wide_counter *c) +{ + uint64_t r = __atomic_wide_counter_load_relaxed (c); + atomic_thread_fence_acquire (); + return r; +} + uint64_t __atomic_wide_counter_fetch_add_relaxed (__atomic_wide_counter *c, unsigned int op) attribute_hidden; diff --git a/include/bits/dl_find_object.h b/include/bits/dl_find_object.h new file mode 100644 index 0000000..7a323d7 --- /dev/null +++ b/include/bits/dl_find_object.h @@ -0,0 +1 @@ +#include_next <bits/dl_find_object.h> diff --git a/include/dlfcn.h b/include/dlfcn.h index e73294b..ae25f05 100644 --- a/include/dlfcn.h +++ b/include/dlfcn.h @@ -4,6 +4,8 @@ #include <link.h> /* For ElfW. */ #include <stdbool.h> +rtld_hidden_proto (_dl_find_object) + /* Internally used flag. */ #define __RTLD_DLOPEN 0x80000000 #define __RTLD_SPROF 0x40000000 diff --git a/include/link.h b/include/link.h index 6a9f788..b49be89 100644 --- a/include/link.h +++ b/include/link.h @@ -211,6 +211,9 @@ struct link_map freed, ie. not allocated with the dummy malloc in ld.so. */ unsigned int l_ld_readonly:1; /* Nonzero if dynamic section is readonly. */ + unsigned int l_find_object_processed:1; /* Zero if _dl_find_object_update + needs to process this + lt_library map. */ /* NODELETE status of the map. Only valid for maps of type lt_loaded. Lazy binding sets l_nodelete_active directly, |