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authorSamuel Thibault <samuel.thibault@ens-lyon.org>2016-11-19 11:49:49 +0100
committerSamuel Thibault <samuel.thibault@ens-lyon.org>2016-11-19 11:49:49 +0100
commitd7ed4dfddca61bfe570d5098e27872b7bbe874bf (patch)
tree0017b333f03fd091c3d1ce88506a11035889be04
parent43ff3daffb0a6b1ec946aee818b418fdd1b8b723 (diff)
parent066cacde241cfbc94c9b1f9af7f64f1f6ccbd9bd (diff)
Merge commit 'refs/top-bases/t/gsync-libc-merge' into t/gsync-libc-merge
-rw-r--r--sysdeps/mach/hurd/fork.c18
-rw-r--r--sysdeps/mach/hurd/i386/makecontext-helper.c71
2 files changed, 87 insertions, 2 deletions
diff --git a/sysdeps/mach/hurd/fork.c b/sysdeps/mach/hurd/fork.c
index 5df993f463..3e7501f9a1 100644
--- a/sysdeps/mach/hurd/fork.c
+++ b/sysdeps/mach/hurd/fork.c
@@ -505,10 +505,24 @@ __fork (void)
(natural_t *) &state, &statecount))
LOSE;
#ifdef STACK_GROWTH_UP
- if (__hurd_sigthread_stack_base != 0)
+ if (__hurd_sigthread_stack_base == 0)
+ {
+ state.SP &= __hurd_threadvar_stack_mask;
+ state.SP += __hurd_threadvar_stack_offset;
+ }
+ else
state.SP = __hurd_sigthread_stack_base;
#else
- if (__hurd_sigthread_stack_end != 0)
+ if (__hurd_sigthread_stack_end == 0)
+ {
+ /* The signal thread has a stack assigned by cthreads.
+ The threadvar_stack variables conveniently tell us how
+ to get to the highest address in the stack, just below
+ the per-thread variables. */
+ state.SP &= __hurd_threadvar_stack_mask;
+ state.SP += __hurd_threadvar_stack_offset;
+ }
+ else
state.SP = __hurd_sigthread_stack_end;
#endif
MACHINE_THREAD_STATE_SET_PC (&state,
diff --git a/sysdeps/mach/hurd/i386/makecontext-helper.c b/sysdeps/mach/hurd/i386/makecontext-helper.c
new file mode 100644
index 0000000000..e604488264
--- /dev/null
+++ b/sysdeps/mach/hurd/i386/makecontext-helper.c
@@ -0,0 +1,71 @@
+/* Helper for makecontext: handle threadvars.
+ Copyright (C) 2013 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#include <hurd/threadvar.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <ucontext.h>
+
+#if 0
+
+void
+__makecontext_helper (ucontext_t *ucp)
+{
+ if (__hurd_threadvar_stack_mask == 0)
+ {
+ /* We are not using threads, so per init-first.c:init, the threadvars
+ live in a malloced space, addressed relative to the base of the
+ virtual address space. Just keep using that one. */
+ }
+ else
+ {
+ /* The following is only prepared to work with libpthread, which only
+ keeps the threadvars at the bottom of the stack -- contrary to
+ libthreads, which also puts additional data there. */
+
+ void *s = ucp->uc_stack.ss_sp;
+ size_t s_size = ucp->uc_stack.ss_size;
+
+ /* Is the new stack suitable? Check that that the last threadvar
+ occupies the last storage unit within the bounds of the new stack.
+ Alignment according to (sp & __hurd_threadvar_stack_mask) == sp is not
+ actually a requirement (though, in practice it often will be). */
+ if (__hurd_threadvar_location_from_sp (_HURD_THREADVAR_MAX, s)
+ != s + s_size)
+ {
+ /* Instead of having makecontext return an error, we bail out the
+ hard way, as we can't expect its caller to be able to properly
+ react to this situation. */
+ fprintf (stderr,
+ "*** makecontext: a stack at %p with size %#x is not "
+ "usable with threadvars\n",
+ s, s_size);
+ abort ();
+ }
+
+ /* Copy the threadvars to the new stack. */
+ void *t_old = __hurd_threadvar_location (0);
+ void *t_new = __hurd_threadvar_location_from_sp (0, s);
+ size_t t_size = __hurd_threadvar_max * sizeof (unsigned long int);
+ memcpy (t_new, t_old, t_size);
+ /* Account for the space taken by the threadvars. */
+ ucp->uc_stack.ss_size -= t_size;
+ }
+}
+#endif