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authorPaul Pluzhnikov <ppluzhnikov@google.com>2013-12-18 16:24:19 -0800
committerPaul Pluzhnikov <ppluzhnikov@google.com>2013-12-18 16:24:19 -0800
commit35e8f7ab94c910659de9d507aa0f3e1f8973d914 (patch)
treefca3c69ec2085dbeee15673472350c9067ddf4f7
parent69a17d9d245dc3551792e95e1823cc2d877592f3 (diff)
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Patch 3/4 of the effort to make TLS access async-signal-safe.
Factor out _dl_clear_dtv. 2013-12-18 Andrew Hunter <ahh@google.com> * elf/Versions (ld): Add _dl_clear_dtv. * sysdeps/generic/ldsodefs.h (_dl_clear_dtv): New prototype. * elf/dl-tls.c (_dl_clear_dtv): New function. * nptl/allocatestack.c (get_cached_stack): Call _dl_clear_dtv.
-rw-r--r--ChangeLog7
-rw-r--r--elf/Versions1
-rw-r--r--elf/dl-tls.c12
-rw-r--r--nptl/allocatestack.c6
-rw-r--r--sysdeps/generic/ldsodefs.h5
5 files changed, 26 insertions, 5 deletions
diff --git a/ChangeLog b/ChangeLog
index 126c92e006..fae243e093 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,12 @@
2013-12-18 Andrew Hunter <ahh@google.com>
+ * elf/Versions (ld): Add _dl_clear_dtv.
+ * sysdeps/generic/ldsodefs.h (_dl_clear_dtv): New prototype.
+ * elf/dl-tls.c (_dl_clear_dtv): New function.
+ * nptl/allocatestack.c (get_cached_stack): Call _dl_clear_dtv.
+
+2013-12-18 Andrew Hunter <ahh@google.com>
+
* sysdeps/generic/ldsodefs.h (_dl_mask_all_signals): New prototype.
(_dl_unmask_signals): Likewise.
* sysdeps/mach/hurd/dl-sysdep.h (_dl_mask_all_signals): New stub.
diff --git a/elf/Versions b/elf/Versions
index 238399232d..01b7a59d5e 100644
--- a/elf/Versions
+++ b/elf/Versions
@@ -53,6 +53,7 @@ ld {
_dl_allocate_tls; _dl_allocate_tls_init;
_dl_argv; _dl_find_dso_for_object; _dl_get_tls_static_info;
_dl_deallocate_tls; _dl_make_stack_executable; _dl_out_of_memory;
+ _dl_clear_dtv;
_dl_rtld_di_serinfo; _dl_starting_up; _dl_tls_setup;
_rtld_global; _rtld_global_ro;
diff --git a/elf/dl-tls.c b/elf/dl-tls.c
index 576d9a1465..c60a6b7b80 100644
--- a/elf/dl-tls.c
+++ b/elf/dl-tls.c
@@ -463,6 +463,18 @@ _dl_allocate_tls (void *mem)
}
rtld_hidden_def (_dl_allocate_tls)
+void
+internal_function
+_dl_clear_dtv (dtv_t *dtv)
+{
+ for (size_t cnt = 0; cnt < dtv[-1].counter; ++cnt)
+ if (! dtv[1 + cnt].pointer.is_static
+ && dtv[1 + cnt].pointer.val != TLS_DTV_UNALLOCATED)
+ free (dtv[1 + cnt].pointer.val);
+ memset (dtv, '\0', (dtv[-1].counter + 1) * sizeof (dtv_t));
+}
+
+rtld_hidden_def (_dl_clear_dtv)
#ifndef SHARED
extern dtv_t _dl_static_dtv[];
diff --git a/nptl/allocatestack.c b/nptl/allocatestack.c
index 1e0fe1f18d..96e3845088 100644
--- a/nptl/allocatestack.c
+++ b/nptl/allocatestack.c
@@ -242,11 +242,7 @@ get_cached_stack (size_t *sizep, void **memp)
/* Clear the DTV. */
dtv_t *dtv = GET_DTV (TLS_TPADJ (result));
- for (size_t cnt = 0; cnt < dtv[-1].counter; ++cnt)
- if (! dtv[1 + cnt].pointer.is_static
- && dtv[1 + cnt].pointer.val != TLS_DTV_UNALLOCATED)
- free (dtv[1 + cnt].pointer.val);
- memset (dtv, '\0', (dtv[-1].counter + 1) * sizeof (dtv_t));
+ _dl_clear_dtv (dtv);
/* Re-initialize the TLS. */
_dl_allocate_tls_init (TLS_TPADJ (result));
diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h
index e919e4136c..1bda60c6fa 100644
--- a/sysdeps/generic/ldsodefs.h
+++ b/sysdeps/generic/ldsodefs.h
@@ -989,6 +989,11 @@ extern void *_dl_allocate_tls_storage (void)
extern void *_dl_allocate_tls_init (void *) internal_function;
rtld_hidden_proto (_dl_allocate_tls_init)
+/* Remove all allocated dynamic TLS regions from a DTV
+ for reuse by new thread. */
+extern void _dl_clear_dtv (dtv_t *dtv) internal_function;
+rtld_hidden_proto (_dl_clear_dtv)
+
/* Deallocate memory allocated with _dl_allocate_tls. */
extern void _dl_deallocate_tls (void *tcb, bool dealloc_tcb) internal_function;
rtld_hidden_proto (_dl_deallocate_tls)