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authorRich Felker <dalias@aerifal.cx>2012-10-15 18:51:53 -0400
committerRich Felker <dalias@aerifal.cx>2012-10-15 18:51:53 -0400
commit9ec4283b28cf676292fd5c6f681bef1e90e30c18 (patch)
tree2897be56744c39158a3e53adfc4e3569b3f8547d /src/ldso
parentd5304147b983f309ed0c9050e3b8b6f2c9f87f43 (diff)
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add support for TLS variant I, presently needed for arm and mips
despite documentation that makes it sound a lot different, the only ABI-constraint difference between TLS variants II and I seems to be that variant II stores the initial TLS segment immediately below the thread pointer (i.e. the thread pointer points to the end of it) and variant I stores the initial TLS segment above the thread pointer, requiring the thread descriptor to be stored below. the actual value stored in the thread pointer register also tends to have per-arch random offsets applied to it for silly micro-optimization purposes. with these changes applied, TLS should be basically working on all supported archs except microblaze. I'm still working on getting the necessary information and a working toolchain that can build TLS binaries for microblaze, but in theory, static-linked programs with TLS and dynamic-linked programs where only the main executable uses TLS should already work on microblaze. alignment constraints have not yet been heavily tested, so it's possible that this code does not always align TLS segments correctly on archs that need TLS variant I.
Diffstat (limited to 'src/ldso')
-rw-r--r--src/ldso/dynlink.c35
1 files changed, 32 insertions, 3 deletions
diff --git a/src/ldso/dynlink.c b/src/ldso/dynlink.c
index 5353979e..2ec8fb8c 100644
--- a/src/ldso/dynlink.c
+++ b/src/ldso/dynlink.c
@@ -539,10 +539,16 @@ static struct dso *load_library(const char *name)
}
p->tls_id = ++tls_cnt;
tls_align = MAXP2(tls_align, p->tls_align);
+#ifdef TLS_ABOVE_TP
+ p->tls_offset = tls_offset + ( (tls_align-1) &
+ -(tls_offset + (uintptr_t)p->tls_image) );
+ tls_offset += p->tls_size;
+#else
tls_offset += p->tls_size + p->tls_align - 1;
tls_offset -= (tls_offset + (uintptr_t)p->tls_image)
& (p->tls_align-1);
p->tls_offset = tls_offset;
+#endif
p->new_dtv = (void *)(-sizeof(size_t) &
(uintptr_t)(p->name+strlen(p->name)+sizeof(size_t)));
p->new_tls = (void *)(p->new_dtv + n_th*(tls_cnt+1));
@@ -697,6 +703,18 @@ void *__copy_tls(unsigned char *mem)
void **dtv = (void *)mem;
dtv[0] = (void *)tls_cnt;
+#ifdef TLS_ABOVE_TP
+ mem += sizeof(void *) * (tls_cnt+1);
+ mem += -((uintptr_t)mem + sizeof(struct pthread)) & (tls_align-1);
+ td = (pthread_t)mem;
+ mem += sizeof(struct pthread);
+
+ for (p=head; p; p=p->next) {
+ if (!p->tls_id) continue;
+ dtv[p->tls_id] = mem + p->tls_offset;
+ memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
+ }
+#else
mem += libc.tls_size - sizeof(struct pthread);
mem -= (uintptr_t)mem & (tls_align-1);
td = (pthread_t)mem;
@@ -706,6 +724,7 @@ void *__copy_tls(unsigned char *mem)
dtv[p->tls_id] = mem - p->tls_offset;
memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
}
+#endif
td->dtv = dtv;
return td;
}
@@ -753,9 +772,12 @@ void *__tls_get_addr(size_t *v)
static void update_tls_size()
{
- size_t below_tp = (1+tls_cnt) * sizeof(void *) + tls_offset;
- size_t above_tp = sizeof(struct pthread) + tls_align;
- libc.tls_size = ALIGN(below_tp + above_tp, tls_align);
+ libc.tls_size = ALIGN(
+ (1+tls_cnt) * sizeof(void *) +
+ tls_offset +
+ sizeof(struct pthread) +
+ tls_align * 2,
+ tls_align);
}
void *__dynlink(int argc, char **argv)
@@ -866,9 +888,16 @@ void *__dynlink(int argc, char **argv)
}
if (app->tls_size) {
app->tls_id = tls_cnt = 1;
+#ifdef TLS_ABOVE_TP
+ app->tls_offset = 0;
+ tls_offset = app->tls_size
+ + ( -((uintptr_t)app->tls_image + app->tls_size)
+ & (app->tls_align-1) );
+#else
tls_offset = app->tls_offset = app->tls_size
+ ( -((uintptr_t)app->tls_image + app->tls_size)
& (app->tls_align-1) );
+#endif
tls_align = MAXP2(tls_align, app->tls_align);
}
app->global = 1;