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Re: PATCH: Compile x86 rtld with -mno-sse -mno-mmx
- From: "H.J. Lu" <hjl dot tools at gmail dot com>
- To: Andreas Jaeger <aj at suse dot com>
- Cc: libc-alpha at sourceware dot org
- Date: Fri, 2 Nov 2012 15:24:28 -0700
- Subject: Re: PATCH: Compile x86 rtld with -mno-sse -mno-mmx
- References: <20121102094135.GA7464@gmail.com><50939F49.8050108@suse.com>
On Fri, Nov 02, 2012 at 11:24:09AM +0100, Andreas Jaeger wrote:
> On 11/02/2012 10:41 AM, H.J. Lu wrote:
> >Hi,
> >
> >This patch compiles x86 rtld with -mno-sse -mno-mmx. It introduces
> >bits/stdlib-float.h so that we can avoid inlined atof in rtld. It
>
> Is that just caution or is there a real usage of atof?
Since it is an inline fuction, GCC issues an error when -mno-sse is
used.
>
> >also avoids <xmmintrin.h> in rtld. We only need a 128-bit type
> >in sysdeps/x86_64/tls.h since we use it with explicit alignment
> >attribute. strcasestr-nonascii.c uses __128mi without including
> ><xmmintrin.h>. This patch fixes it. -mno-sse -mno-mmx applie
> >to both ia32 and x86-64 rtld since GCC may use SSE registers even
> >in 32-bit, especially with LRA in GCC 4.8 which uses SSE registers
> >for GPR spill in 32-bit.
> >
> >Tested on ia32 and x86-64. OK to install?
> >
> >Thanks.
> >
> >
> >H.J.
> >---
> >2012-11-02 H.J. Lu <hongjiu.lu@intel.com>
> >
> > * stdlib/Makefile (headers): Add bits/stdlib-float.h.
> > * stdlib/stdlib.h (atof): Moved to ...
> > * include/bits/stdlib-float.h: Here. New file.
> > * stdlib/stdlib.h: Include <bits/stdlib-float.h>.
> > * stdlib/bits/stdlib-float.h: New file.
> > * sysdeps/x86/Makefile (CFLAGS-.os): Compile rtld routines with
> > -mno-sse -mno-mmx.
> > * sysdeps/x86_64/multiarch/strcasestr-nonascii.c: Include
> > <xmmintrin.h>.
> >
> >nptl/
> >
> >2012-11-02 H.J. Lu <hongjiu.lu@intel.com>
> >
> > * sysdeps/x86_64/tls.h: Don't include <xmmintrin.h>.
> > (__128bits): New struct typedef.
> > (tcbhead_t): Replace __m128 with __128bits.
> >
> >diff --git a/include/bits/stdlib-float.h b/include/bits/stdlib-float.h
> >new file mode 100644
> >index 0000000..d3f5c5b
> >--- /dev/null
> >+++ b/include/bits/stdlib-float.h
> >@@ -0,0 +1,4 @@
> >+/* No floating-point inline functions in rtld. */
> >+#ifndef IS_IN_rtld
> >+# include <stdlib/bits/stdlib-float.h>
> >+#endif
>
> I suggest to use #include_next <bits/stdlib-float.h> here, an
> architecture might want to override the file.
<stdlib.h> can't be overrided by architecture since it is placed
under stdlib and -I../stdlib isn't used to compile glibc. We use
#include <stdlib/stdlib.h>
in include/stdlib.h.
>
> >diff --git a/nptl/sysdeps/x86_64/tls.h b/nptl/sysdeps/x86_64/tls.h
> >index b651d1c..4dee137 100644
> >--- a/nptl/sysdeps/x86_64/tls.h
> >+++ b/nptl/sysdeps/x86_64/tls.h
> >@@ -27,7 +27,10 @@
> > # include <stdlib.h>
> > # include <sysdep.h>
> > # include <kernel-features.h>
> >-# include <xmmintrin.h>
> >+typedef struct
> >+{
> >+ int i[4];
> >+} __128bits;
> >
> >
> > /* Type for the dtv. */
> >@@ -64,7 +67,7 @@ typedef struct
> > void *__private_tm[5];
> > long int __unused2;
> > /* Have space for the post-AVX register size. */
> >- __m128 rtld_savespace_sse[8][4] __attribute__ ((aligned (32)));
> >+ __128bits rtld_savespace_sse[8][4] __attribute__ ((aligned (32)));
>
> I suggest to add a comment above why __m128 is not used here.
Done.
>
> I'd like somebody else to review this as well,
>
I also fixed the typo pointed out by Chris. OK to install?
Thanks.
H.J.
---
2012-11-02 H.J. Lu <hongjiu.lu@intel.com>
* stdlib/Makefile (headers): Add bits/stdlib-float.h.
* stdlib/stdlib.h (atof): Moved to ...
* include/bits/stdlib-float.h: Here. New file.
* stdlib/stdlib.h: Include <bits/stdlib-float.h>.
* stdlib/bits/stdlib-float.h: New file.
* sysdeps/x86/Makefile (CFLAGS-.os): Compile rtld routines with
-mno-sse -mno-mmx.
* sysdeps/x86_64/multiarch/strcasestr-nonascii.c: Include
<xmmintrin.h>.
nptl/
2012-11-02 H.J. Lu <hongjiu.lu@intel.com>
* sysdeps/x86_64/tls.h: Don't include <xmmintrin.h>.
(__128bits): New struct typedef.
(tcbhead_t): Replace __m128 with __128bits.
diff --git a/include/bits/stdlib-float.h b/include/bits/stdlib-float.h
new file mode 100644
index 0000000..d3f5c5b
--- /dev/null
+++ b/include/bits/stdlib-float.h
@@ -0,0 +1,4 @@
+/* No floating-point inline functions in rtld. */
+#ifndef IS_IN_rtld
+# include <stdlib/bits/stdlib-float.h>
+#endif
diff --git a/nptl/sysdeps/x86_64/tls.h b/nptl/sysdeps/x86_64/tls.h
index b651d1c..bc60a51 100644
--- a/nptl/sysdeps/x86_64/tls.h
+++ b/nptl/sysdeps/x86_64/tls.h
@@ -27,7 +27,14 @@
# include <stdlib.h>
# include <sysdep.h>
# include <kernel-features.h>
-# include <xmmintrin.h>
+
+/* Replacement type for __m128 since this file is included by ld.so,
+ which is compiled with -mno-sse. It must not change the alignment
+ of rtld_savespace_sse. */
+typedef struct
+{
+ int i[4];
+} __128bits;
/* Type for the dtv. */
@@ -64,7 +71,7 @@ typedef struct
void *__private_tm[5];
long int __unused2;
/* Have space for the post-AVX register size. */
- __m128 rtld_savespace_sse[8][4] __attribute__ ((aligned (32)));
+ __128bits rtld_savespace_sse[8][4] __attribute__ ((aligned (32)));
void *__padding[8];
} tcbhead_t;
diff --git a/stdlib/Makefile b/stdlib/Makefile
index 57830a8..5e99d7f 100644
--- a/stdlib/Makefile
+++ b/stdlib/Makefile
@@ -20,7 +20,7 @@
#
subdir := stdlib
-headers := stdlib.h bits/stdlib.h bits/stdlib-ldbl.h \
+headers := stdlib.h bits/stdlib.h bits/stdlib-ldbl.h bits/stdlib-float.h \
monetary.h bits/monetary-ldbl.h \
inttypes.h stdint.h bits/wordsize.h \
errno.h sys/errno.h bits/errno.h \
diff --git a/stdlib/bits/stdlib-float.h b/stdlib/bits/stdlib-float.h
new file mode 100644
index 0000000..46f3a32
--- /dev/null
+++ b/stdlib/bits/stdlib-float.h
@@ -0,0 +1,31 @@
+/* Floating-point inline functions for stdlib.h.
+ Copyright (C) 2012 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/>. */
+
+#ifndef _STDLIB_H
+# error "Never use <bits/stdlib-float.h> directly; include <stdlib.h> instead."
+#endif
+
+#ifdef __USE_EXTERN_INLINES
+__BEGIN_NAMESPACE_STD
+__extern_inline double
+__NTH (atof (const char *__nptr))
+{
+ return strtod (__nptr, (char **) NULL);
+}
+__END_NAMESPACE_STD
+#endif /* Optimizing and Inlining. */
diff --git a/stdlib/stdlib.h b/stdlib/stdlib.h
index cf3f39c..0eb982c 100644
--- a/stdlib/stdlib.h
+++ b/stdlib/stdlib.h
@@ -274,11 +274,6 @@ extern long double strtold_l (const char *__restrict __nptr,
#ifdef __USE_EXTERN_INLINES
__BEGIN_NAMESPACE_STD
-__extern_inline double
-__NTH (atof (const char *__nptr))
-{
- return strtod (__nptr, (char **) NULL);
-}
__extern_inline int
__NTH (atoi (const char *__nptr))
{
@@ -953,6 +948,7 @@ extern int getloadavg (double __loadavg[], int __nelem)
__THROW __nonnull ((1));
#endif
+#include <bits/stdlib-float.h>
/* Define some macros helping to catch buffer overflows. */
#if __USE_FORTIFY_LEVEL > 0 && defined __fortify_function
diff --git a/sysdeps/x86/Makefile b/sysdeps/x86/Makefile
index 7589b25..c024729 100644
--- a/sysdeps/x86/Makefile
+++ b/sysdeps/x86/Makefile
@@ -1,4 +1,6 @@
ifeq ($(subdir),elf)
+CFLAGS-.os += $(if $(filter $(@F),$(patsubst %,%.os,$(all-rtld-routines))),\
+ -mno-sse -mno-mmx)
tests: $(objpfx)tst-xmmymm.out
$(objpfx)tst-xmmymm.out: ../sysdeps/x86/tst-xmmymm.sh $(objpfx)ld.so
@echo "Checking ld.so for SSE register use. This will take a few seconds..."
diff --git a/sysdeps/x86_64/multiarch/strcasestr-nonascii.c b/sysdeps/x86_64/multiarch/strcasestr-nonascii.c
index a1f9968..db84a43 100644
--- a/sysdeps/x86_64/multiarch/strcasestr-nonascii.c
+++ b/sysdeps/x86_64/multiarch/strcasestr-nonascii.c
@@ -16,7 +16,8 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
-# include <ctype.h>
+#include <ctype.h>
+#include <xmmintrin.h>
/* Similar to __m128i_strloadu. Convert to lower case for none-POSIX/C