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authorUlrich Drepper <drepper@gmail.com>2011-04-18 02:51:26 +0100
committerPetr Baudis <pasky@ucw.cz>2011-05-27 00:34:37 +0200
commit8277fdc1cd54428e54e112db7f5be89303951001 (patch)
treec57104842eda4298e94781c1c033823f120b0075
parentfea332e16416691310088b5c0e6797694c88352b (diff)
downloadglibc-8277fdc1cd54428e54e112db7f5be89303951001.tar.gz
Fix FPU context handling in getcontext on x86-64.
fnstenv on x86-64 seems to clear the state. Work around. (cherry picked from commit 75ea32abcde4e1699328354e1804ea94560d2950)
-rw-r--r--ChangeLog8
-rw-r--r--stdlib/Makefile11
-rw-r--r--stdlib/bug-getcontext.c48
-rw-r--r--sysdeps/unix/sysv/linux/x86_64/getcontext.S3
4 files changed, 67 insertions, 3 deletions
diff --git a/ChangeLog b/ChangeLog
index a50025b7fe..9d8ecac572 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2011-04-17 Ulrich Drepper <drepper@gmail.com>
+
+ [BZ #12420]
+ * sysdeps/unix/sysv/linux/x86_64/getcontext.S: Reload context after
+ storing it.
+ * stdlib/bug-getcontext.c: New file.
+ * stdlib/Makefile: Add rules to build and run bug-getcontext.
+
2011-04-10 Ulrich Drepper <drepper@gmail.com>
[BZ #12650]
diff --git a/stdlib/Makefile b/stdlib/Makefile
index d361dd8ffa..6b8e0219c5 100644
--- a/stdlib/Makefile
+++ b/stdlib/Makefile
@@ -1,4 +1,4 @@
-# Copyright (C) 1991-2006, 2007, 2008, 2009 Free Software Foundation, Inc.
+# Copyright (C) 1991-2009, 2011 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
@@ -70,7 +70,7 @@ tests := tst-strtol tst-strtod testmb testrand testsort testdiv \
test-a64l tst-qsort tst-system testmb2 bug-strtod2 \
tst-atof1 tst-atof2 tst-strtod2 tst-strtod3 tst-rand48-2 \
tst-makecontext tst-strtod4 tst-strtod5 tst-qsort2 \
- tst-makecontext2 tst-strtod6 tst-unsetenv1
+ tst-makecontext2 tst-strtod6 tst-unsetenv1 bug-getcontext
include ../Makeconfig
@@ -144,3 +144,10 @@ $(objpfx)tst-putenv: $(objpfx)tst-putenvmod.so
$(objpfx)tst-putenvmod.so: $(objpfx)tst-putenvmod.os
$(build-module)
CFLAGS-tst-putenvmod.c = -DNOT_IN_libc=1
+
+ifeq ($(build-shared),yes)
+link-libm = $(common-objpfx)math/libm.so
+else
+link-libm = $(common-objpfx)math/libm.a
+endif
+$(objpfx)bug-getcontext: $(link-libm)
diff --git a/stdlib/bug-getcontext.c b/stdlib/bug-getcontext.c
new file mode 100644
index 0000000000..745aa1f207
--- /dev/null
+++ b/stdlib/bug-getcontext.c
@@ -0,0 +1,48 @@
+/* BZ 12420 */
+
+#include <errno.h>
+#include <fenv.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <ucontext.h>
+
+static int
+do_test (void)
+{
+ int except_mask = FE_DIVBYZERO | FE_INVALID | FE_OVERFLOW | FE_UNDERFLOW;
+ int status = feenableexcept (except_mask);
+
+ except_mask = fegetexcept ();
+ if (except_mask == -1)
+ {
+ printf("\nBefore getcontext(): fegetexcept returned: %d\n",
+ except_mask);
+ return 1;
+ }
+
+ ucontext_t ctx;
+ status = getcontext(&ctx);
+ if (status)
+ {
+ printf("\ngetcontext failed, errno: %d.\n", errno);
+ return 1;
+ }
+
+ printf ("\nDone with getcontext()!\n");
+ fflush (NULL);
+
+ int mask = fegetexcept ();
+ if (mask != except_mask)
+ {
+ printf("\nAfter getcontext(): fegetexcept returned: %d, expected: %d.\n",
+ mask, except_mask);
+ return 1;
+ }
+
+ printf("\nAt end fegetexcept() returned %d, expected: %d.\n",
+ mask, except_mask);
+ return 0;
+}
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"
diff --git a/sysdeps/unix/sysv/linux/x86_64/getcontext.S b/sysdeps/unix/sysv/linux/x86_64/getcontext.S
index 4bbc7a4d2e..1a31d72dad 100644
--- a/sysdeps/unix/sysv/linux/x86_64/getcontext.S
+++ b/sysdeps/unix/sysv/linux/x86_64/getcontext.S
@@ -1,5 +1,5 @@
/* Save current context.
- Copyright (C) 2002, 2005 Free Software Foundation, Inc.
+ Copyright (C) 2002, 2005, 2011 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Andreas Jaeger <aj@suse.de>, 2002.
@@ -62,6 +62,7 @@ ENTRY(__getcontext)
movq %rcx, oFPREGS(%rdi)
/* Save the floating-point environment. */
fnstenv (%rcx)
+ fldenv (%rcx)
stmxcsr oMXCSR(%rdi)
/* Save the current signal mask with