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For variant II static TLS, properly align tls segments. Pre-calculate

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the max required alignment for the static tls segments, and honor it
when carving the pieces for next module, from the static space.  Use
aligned allocator to get properly-aligned dynamic blocks.

Reported by:	dt71@gmx.com
Reviewed by:	kan
Sponsored by:	The FreeBSD Foundation
MFC after:	1 week
This commit is contained in:
Konstantin Belousov 2013-12-06 21:39:45 +00:00
parent dfe296c43a
commit 16a93df7eb
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=259044
1 changed files with 20 additions and 15 deletions
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35
libexec/rtld-elf/rtld.c
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@ -231,6 +231,7 @@ char **main_argv;
size_t tls_last_offset; /* Static TLS offset of last module */
size_t tls_last_size; /* Static TLS size of last module */
size_t tls_static_space; /* Static TLS space allocated */
size_t tls_static_max_align;
int tls_dtv_generation = 1; /* Used to detect when dtv size changes */
int tls_max_index = 1; /* Largest module index allocated */
@ -4281,19 +4282,22 @@ void *
allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
{
Obj_Entry *obj;
size_t size;
size_t size, ralign;
char *tls;
Elf_Addr *dtv, *olddtv;
Elf_Addr segbase, oldsegbase, addr;
int i;
size = round(tls_static_space, tcbalign);
ralign = tcbalign;
if (tls_static_max_align > ralign)
ralign = tls_static_max_align;
size = round(tls_static_space, ralign) + round(tcbsize, ralign);
assert(tcbsize >= 2*sizeof(Elf_Addr));
tls = xcalloc(1, size + tcbsize);
tls = malloc_aligned(size, ralign);
dtv = xcalloc(tls_max_index + 2, sizeof(Elf_Addr));
segbase = (Elf_Addr)(tls + size);
segbase = (Elf_Addr)(tls + round(tls_static_space, ralign));
((Elf_Addr*)segbase)[0] = segbase;
((Elf_Addr*)segbase)[1] = (Elf_Addr) dtv;
@ -4345,8 +4349,8 @@ allocate_tls(Obj_Entry *objs, void *oldtls, size_t tcbsize, size_t tcbalign)
void
free_tls(void *tls, size_t tcbsize, size_t tcbalign)
{
size_t size;
Elf_Addr* dtv;
size_t size, ralign;
int dtvsize, i;
Elf_Addr tlsstart, tlsend;
@ -4354,19 +4358,22 @@ free_tls(void *tls, size_t tcbsize, size_t tcbalign)
* Figure out the size of the initial TLS block so that we can
* find stuff which ___tls_get_addr() allocated dynamically.
*/
size = round(tls_static_space, tcbalign);
ralign = tcbalign;
if (tls_static_max_align > ralign)
ralign = tls_static_max_align;
size = round(tls_static_space, ralign);
dtv = ((Elf_Addr**)tls)[1];
dtvsize = dtv[1];
tlsend = (Elf_Addr) tls;
tlsstart = tlsend - size;
for (i = 0; i < dtvsize; i++) {
if (dtv[i+2] && (dtv[i+2] < tlsstart || dtv[i+2] > tlsend)) {
free((void*) dtv[i+2]);
if (dtv[i + 2] != 0 && (dtv[i + 2] < tlsstart || dtv[i + 2] > tlsend)) {
free_aligned(dtv[i + 2]);
}
}
free((void*) tlsstart);
free_aligned(tlsstart);
free((void*) dtv);
}
@ -4390,11 +4397,7 @@ allocate_module_tls(int index)
die();
}
p = malloc(obj->tlssize);
if (p == NULL) {
_rtld_error("Cannot allocate TLS block for index %d", index);
die();
}
p = malloc_aligned(obj->tlssize, obj->tlsalign);
memcpy(p, obj->tlsinit, obj->tlsinitsize);
memset(p + obj->tlsinitsize, 0, obj->tlssize - obj->tlsinitsize);
@ -4426,9 +4429,11 @@ allocate_tls_offset(Obj_Entry *obj)
* leave a small amount of space spare to be used for dynamically
* loading modules which use static TLS.
*/
if (tls_static_space) {
if (tls_static_space != 0) {
if (calculate_tls_end(off, obj->tlssize) > tls_static_space)
return false;
} else if (obj->tlsalign > tls_static_max_align) {
tls_static_max_align = obj->tlsalign;
}
tls_last_offset = obj->tlsoffset = off;