Date: Mon, 9 Apr 2012 20:44:16 +1200 From: Andrew Turner <andrew@fubar.geek.nz> To: Juli Mallett <jmallett@FreeBSD.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r234014 - head/lib/libc/arm/gen Message-ID: <20120409204416.77f61674@fubar.geek.nz> In-Reply-To: <CACVs6=_t=VSqA-DTZi-rNxpE9bEZRzaHDSVe0FVw0xDV4c3Q=Q@mail.gmail.com> References: <201204080436.q384aRXS093116@svn.freebsd.org> <20120408164521.55aecdd1@fubar.geek.nz> <CACVs6=8SW9PhZaxc4KRnVyo5p6NyhdD09_cAowLCbgczDqBsVg@mail.gmail.com> <20120409161453.29d1f3de@fubar.geek.nz> <CACVs6=_t=VSqA-DTZi-rNxpE9bEZRzaHDSVe0FVw0xDV4c3Q=Q@mail.gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
--MP_/72Cj3Dkup914XX3fIuDB5o=
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Content-Disposition: inline
On Mon, 9 Apr 2012 01:03:15 -0700
Juli Mallett <jmallett@FreeBSD.org> wrote:
> On Sun, Apr 8, 2012 at 21:14, Andrew Turner <andrew@fubar.geek.nz>
> wrote:
> > We can implement it as a naked function but we will need to store
> > all registers other than r0 and pc which seems a waste.
> >
> > The problem implementing it in an assembly file is we are unable to
> > use ARM_TP_ADDRESS is defined as:
> > #define ARM_TP_ADDRESS (ARM_VECTORS_HIGH + 0x1000)
> >
> > Where ARM_VECTORS_HIGH is defined as:
> > #define ARM_VECTORS_HIGH 0xffff0000U
> >
> > I could remove the U from ARM_VECTORS_HIGH however I'm not sure on
> > the implications of that change.
>
> Oh, is that all? :) It's easy to have an ifdef that adds the u
> suffix in C and not in assembly. That's perfectly appropriate in this
> case. If you want to be fancy you can use a macro which adds the U to
> the constant in C and not in assembly, and use it in other places, but
> that's usually unnecessary. In the kernel we sometimes use assym to
> get around this sort of thing, but that's fully unnecessary.
>
> Look at powerpc/include/vmparam.h for an example of a header where we
> do this currently (VM_MAXUSER_ADDRESS specifically.) This is the
> right thing to do by far over using C as a wrapper for assembly in
> this way.
How does the attached (untested) patch look. It explicitly loads
ARM_TP_ADDRESS into a r0 to ensure r1-3 are not touched.
Andrew
--MP_/72Cj3Dkup914XX3fIuDB5o=
Content-Type: text/x-patch
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment; filename=arm_tls.patch
Index: lib/libc/arm/gen/Makefile.inc
===================================================================
--- lib/libc/arm/gen/Makefile.inc (revision 234031)
+++ lib/libc/arm/gen/Makefile.inc (working copy)
@@ -3,4 +3,4 @@
SRCS+= _ctx_start.S _setjmp.S _set_tp.c alloca.S fabs.c \
getcontextx.c infinity.c ldexp.c makecontext.c \
- __aeabi_read_tp.c setjmp.S signalcontext.c sigsetjmp.S divsi3.S flt_rounds.c
+ __aeabi_read_tp.S setjmp.S signalcontext.c sigsetjmp.S divsi3.S flt_rounds.c
Index: lib/libc/arm/gen/__aeabi_read_tp.S
===================================================================
--- lib/libc/arm/gen/__aeabi_read_tp.S (revision 0)
+++ lib/libc/arm/gen/__aeabi_read_tp.S (working copy)
@@ -0,0 +1,41 @@
+/*-
+ * Copyright (c) 2012 Oleksandr Tymoshenko
+ * Copyright (c) 2012 Andrew Turner
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <machine/asm.h>
+__FBSDID("$FreeBSD$");
+
+#define LOCORE
+#include <machine/sysarch.h>
+
+ENTRY(__aeabi_read_tp)
+ ldr r0, .Larm_tp_address
+ ldr r0, [r0]
+ RET
+
+.Larm_tp_address:
+ .word ARM_TP_ADDRESS
+
Index: lib/libc/arm/gen/__aeabi_read_tp.c
===================================================================
--- lib/libc/arm/gen/__aeabi_read_tp.c (revision 234031)
+++ lib/libc/arm/gen/__aeabi_read_tp.c (working copy)
@@ -1,45 +0,0 @@
-/*-
- * Copyright (c) 2012 Oleksandr Tymoshenko
- * Copyright (c) 2012 Andrew Turner
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
- * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
- * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
- * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
- * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
- * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
- * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
- * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
- * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- *
- * $FreeBSD$
- */
-
-#include <sys/cdefs.h>
-__FBSDID("$FreeBSD$");
-
-#include <sys/types.h>
-
-#include "machine/sysarch.h"
-
-void *
-__aeabi_read_tp()
-{
- void *_tp;
-
- asm("ldr %0, [%1]\n" : "=r"(_tp) : "r"(ARM_TP_ADDRESS));
-
- return _tp;
-}
Index: sys/arm/include/armreg.h
===================================================================
--- sys/arm/include/armreg.h (revision 234031)
+++ sys/arm/include/armreg.h (working copy)
@@ -316,8 +316,13 @@
/*
* Address of the vector page, low and high versions.
*/
+#ifndef LOCORE
#define ARM_VECTORS_LOW 0x00000000U
#define ARM_VECTORS_HIGH 0xffff0000U
+#else
+#define ARM_VECTORS_LOW 0
+#define ARM_VECTORS_HIGH 0xffff0000
+#endif
/*
* ARM Instructions
--MP_/72Cj3Dkup914XX3fIuDB5o=--
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20120409204416.77f61674>