summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorRich Felker <dalias@aerifal.cx>2013-08-03 16:27:30 -0400
committerRich Felker <dalias@aerifal.cx>2013-08-03 16:27:30 -0400
commit7c6c290695cb8726e876ff4fb8413913f661fc0b (patch)
tree9bba80c02f293fcf759bd9b2fe0004f99ac96fae
parent7356c2554e33cf16768616e8e3ae4a4f5a5aac17 (diff)
downloadmusl-7c6c290695cb8726e876ff4fb8413913f661fc0b.tar.gz
add system for resetting TLS to initial values
this is needed for reused threads in the SIGEV_THREAD timer notification system, and could be reused elsewhere in the future if needed, though it should be refactored for such use. for static linking, __init_tls.c is simply modified to export the TLS info in a structure with external linkage, rather than using statics. this perhaps makes the code more clear, since the statics were poorly named for statics. the new __reset_tls.c is only linked if it is used. for dynamic linking, the code is in dynlink.c. sharing code with __copy_tls is not practical since __reset_tls must also re-zero thread-local bss.
-rw-r--r--src/env/__init_tls.c32
-rw-r--r--src/env/__reset_tls.c22
-rw-r--r--src/ldso/dynlink.c13
-rw-r--r--src/time/timer_create.c3
4 files changed, 56 insertions, 14 deletions
diff --git a/src/env/__init_tls.c b/src/env/__init_tls.c
index a4704f06..5c176811 100644
--- a/src/env/__init_tls.c
+++ b/src/env/__init_tls.c
@@ -8,29 +8,33 @@
#ifndef SHARED
-static void *image;
-static size_t len, size, align;
+struct tls_image {
+ void *image;
+ size_t len, size, align;
+} __static_tls ATTR_LIBC_VISIBILITY;
+
+#define T __static_tls
void *__copy_tls(unsigned char *mem)
{
pthread_t td;
- if (!image) return mem;
+ if (!T.image) return mem;
void **dtv = (void *)mem;
dtv[0] = (void *)1;
#ifdef TLS_ABOVE_TP
mem += sizeof(void *) * 2;
- mem += -((uintptr_t)mem + sizeof(struct pthread)) & (align-1);
+ mem += -((uintptr_t)mem + sizeof(struct pthread)) & (T.align-1);
td = (pthread_t)mem;
mem += sizeof(struct pthread);
#else
mem += libc.tls_size - sizeof(struct pthread);
- mem -= (uintptr_t)mem & (align-1);
+ mem -= (uintptr_t)mem & (T.align-1);
td = (pthread_t)mem;
- mem -= size;
+ mem -= T.size;
#endif
td->dtv = dtv;
dtv[1] = mem;
- memcpy(mem, image, len);
+ memcpy(mem, T.image, T.len);
return td;
}
@@ -73,15 +77,15 @@ void __init_tls(size_t *aux)
}
if (!tls_phdr) return;
- image = (void *)(base + tls_phdr->p_vaddr);
- len = tls_phdr->p_filesz;
- size = tls_phdr->p_memsz;
- align = tls_phdr->p_align;
+ T.image = (void *)(base + tls_phdr->p_vaddr);
+ T.len = tls_phdr->p_filesz;
+ T.size = tls_phdr->p_memsz;
+ T.align = tls_phdr->p_align;
- size += (-size - (uintptr_t)image) & (align-1);
- if (align < 4*sizeof(size_t)) align = 4*sizeof(size_t);
+ T.size += (-T.size - (uintptr_t)T.image) & (T.align-1);
+ if (T.align < 4*sizeof(size_t)) T.align = 4*sizeof(size_t);
- libc.tls_size = 2*sizeof(void *)+size+align+sizeof(struct pthread);
+ libc.tls_size = 2*sizeof(void *)+T.size+T.align+sizeof(struct pthread);
mem = __mmap(0, libc.tls_size, PROT_READ|PROT_WRITE,
MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
diff --git a/src/env/__reset_tls.c b/src/env/__reset_tls.c
new file mode 100644
index 00000000..28c4405e
--- /dev/null
+++ b/src/env/__reset_tls.c
@@ -0,0 +1,22 @@
+#ifndef SHARED
+
+#include <string.h>
+#include "pthread_impl.h"
+#include "libc.h"
+
+extern struct tls_image {
+ void *image;
+ size_t len, size, align;
+} __static_tls ATTR_LIBC_VISIBILITY;
+
+#define T __static_tls
+
+void __reset_tls()
+{
+ if (!T.size) return;
+ pthread_t self = __pthread_self();
+ memcpy(self->dtv[1], T.image, T.len);
+ memset((char *)self->dtv[1]+T.len, 0, T.size-T.len);
+}
+
+#endif
diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c
index d689f96e..fa5ad004 100644
--- a/src/ldso/dynlink.c
+++ b/src/ldso/dynlink.c
@@ -783,6 +783,19 @@ void _dl_debug_state(void)
{
}
+void __reset_tls()
+{
+ pthread_t self = __pthread_self();
+ struct dso *p;
+ for (p=head; p; p=p->next) {
+ if (!p->tls_id || !self->dtv[p->tls_id]) continue;
+ memcpy(self->dtv[p->tls_id], p->tls_image, p->tls_len);
+ memset((char *)self->dtv[p->tls_id]+p->tls_len, 0,
+ p->tls_size - p->tls_len);
+ if (p->tls_id == (size_t)self->dtv[0]) break;
+ }
+}
+
void *__copy_tls(unsigned char *mem)
{
pthread_t td;
diff --git a/src/time/timer_create.c b/src/time/timer_create.c
index 2b4619d4..ee6a9c9d 100644
--- a/src/time/timer_create.c
+++ b/src/time/timer_create.c
@@ -19,6 +19,8 @@ static void dummy_1(pthread_t self)
}
weak_alias(dummy_1, __pthread_tsd_run_dtors);
+void __reset_tls();
+
static void cleanup_fromsig(void *p)
{
pthread_t self = __pthread_self();
@@ -28,6 +30,7 @@ static void cleanup_fromsig(void *p)
self->canceldisable = 0;
self->cancelasync = 0;
self->unblock_cancel = 0;
+ __reset_tls();
longjmp(p, 1);
}