previously, the layout of the static TLS block was perturbed by the
size of the dtv; dtv size increasing from 0 to 1 perturbed both TLS
arch types, and the TLS-above-TP type's layout was perturbed by the
specific number of dtv slots (libraries with TLS). this behavior made
it virtually impossible to setup a tentative thread pointer address
before loading libraries and keep it unchanged as long as the
libraries' TLS size/alignment requirements fit.
the new code fixes the location of the dtv and pthread structure at
opposite ends of the static TLS block so that they will not move
unless size or alignment changes.
{
pthread_t td;
struct dso *p;
{
pthread_t td;
struct dso *p;
-
- void **dtv = (void *)mem;
- dtv[0] = (void *)tls_cnt;
- if (!tls_cnt) {
- td = (void *)(dtv+1);
- td->dtv = td->dtv_copy = dtv;
- return td;
- }
- mem += sizeof(void *) * (tls_cnt+1);
+ dtv = (void **)(mem + libc.tls_size) - (tls_cnt + 1);
+
mem += -((uintptr_t)mem + sizeof(struct pthread)) & (tls_align-1);
td = (pthread_t)mem;
mem += sizeof(struct pthread);
mem += -((uintptr_t)mem + sizeof(struct pthread)) & (tls_align-1);
td = (pthread_t)mem;
mem += sizeof(struct pthread);
memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
}
#else
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;
mem += libc.tls_size - sizeof(struct pthread);
mem -= (uintptr_t)mem & (tls_align-1);
td = (pthread_t)mem;
memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
}
#endif
memcpy(dtv[p->tls_id], p->tls_image, p->tls_len);
}
#endif
+ dtv[0] = (void *)tls_cnt;
td->dtv = td->dtv_copy = dtv;
return td;
}
td->dtv = td->dtv_copy = dtv;
return td;
}