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Description: Fix libpthread's __thread_self on most non-x86 platforms
The thread descriptor is (in general) not to be found at the thread
pointer register (that's where the TCB is). The code for x86 (both 32
and 64 bit) does this correctly because it directly reads the ->self
data member (via a segment register based memory access). However, the
other platforms would just return the thread pointer directly - and
hence the wrong data structure.
.
Since there are open questions w.r.t. the TCB layout on msot platforms
fall back to the less efficient (but working) global search on non-x86
for now.
Author: Christian Seiler <christian@iwakd.de>
Last-Update: 2017-01-06
--- a/libpthread/pthread_internal.c
+++ b/libpthread/pthread_internal.c
@@ -110,21 +110,9 @@ static _pthread_descr __thread_find_(int
/* get thread-self descriptor O(1)/O(n*) */
_pthread_descr __thread_self(void) {
/* O(1) "search" */
-#if defined(__alpha__)
- register _pthread_descr cur asm("$0");
- asm("call_pal 158" : "=r"(cur) ); /* PAL_rduniq = 158 */
-#else /* alpha */
register _pthread_descr cur=0;
-#if defined(__sparc__)
- asm("mov %%g6,%0" : "=r"(cur) ); /* %g6 (res. system use) is used as thread pointer */
-#elif defined(__s390__)
- asm("ear %0,%%a0" : "=d"(cur) ); /* a0 (access register 0) is used as thread pointer */
-#elif defined(__ia64__)
- asm("mov %0 = r13" : "=r"(cur) ); /* r13 (tp) is used as thread pointer */
-#elif defined(__x86_64__)
+#if defined(__x86_64__)
asm("mov %%fs:(16),%0" : "=r"(cur));
-#elif defined(__aarch64__)
- asm("mrs %0, tpidr_el0" : "=r"(cur));
#elif defined(__i386__)
if (__likely(__modern_linux==1))
asm("mov %%gs:(8),%0" : "=r"(cur));
@@ -139,7 +127,6 @@ _pthread_descr __thread_self(void) {
cur=__thread_find_(getpid());
if (cur) UNLOCK(cur);
#endif /* other */
-#endif /* alpha */
return (cur)?cur:&_main_thread;
}
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