Changeset 40abf56 in mainline for uspace/lib/c/generic/libc.c

Timestamp:

2018-07-18T19:42:28Z (7 years ago)

Author:

Jiří Zárevúcky <jiri.zarevucky@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

9bde0d5

Parents:

0b05082

git-author:

Jiří Zárevúcky <jiri.zarevucky@…> (2018-07-18 19:05:08)

git-committer:

Jiří Zárevúcky <jiri.zarevucky@…> (2018-07-18 19:42:28)

Message:

Make sure that a thread with uninitialized TLS does not need to call malloc()
to initialize it.

For threads and tasks created by loader, we create TLS beforehand and pass
it to the child. For tasks spawned directly by the kernel, we require it is
a static executable and allocate the initial TLS using as_area_create() instead
of the libc allocator.

File:

• uspace/lib/c/generic/libc.c (modified) (3 diffs)

uspace/lib/c/generic/libc.c

@@ -63 +63 @@
 progsymbols_t __progsymbols;
 
-static bool env_setup = false;
+static bool env_setup;
+static fibril_t main_fibril;
 
 void __libc_main(void *pcb_ptr)
 {
+        assert(!__tcb_is_set());
+
+        __pcb = (pcb_t *) pcb_ptr;
+
+        if (__pcb) {
+                main_fibril.tcb = __pcb->tcb;
+        } else {
+                /*
+                 * Loaded by kernel, not the loader.
+                 * Kernel only supports loading fully static binaries,
+                 * so we can do basic initialization without worrying about
+                 * dynamic libraries.
+                 */
+
+                main_fibril.tcb = tls_make_initial(__progsymbols.elfstart);
+        }
+
+        assert(main_fibril.tcb);
+
+        /* Initialize the fibril. */
+        main_fibril.tcb->fibril_data = &main_fibril;
+        __tcb_set(main_fibril.tcb);
+        fibril_setup(&main_fibril);
+
         /* Initialize user task run-time environment */
         __malloc_init();
-
-        /* Save the PCB pointer */
-        __pcb = (pcb_t *) pcb_ptr;
 
 #ifdef CONFIG_RTLD
@@ -81 +103 @@
         }
 #endif
-
-        fibril_t *fibril = fibril_setup();
-        if (fibril == NULL)
-                abort();
-
-        __tcb_set(fibril->tcb);
 
         __async_server_init();
@@ -151 +167 @@
                 __stdio_done();
                 task_retval(status);
-                fibril_teardown(__tcb_get()->fibril_data, false);
         }