[committed] hppa: Implement swapcontext in assembler (bug 28960)

[committed] hppa: Implement swapcontext in assembler (bug 28960)

[John David Anglin]

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When swapcontext.c is compiled without -g, the following error occurs:
Error: CFI instruction used without previous .cfi_startproc

Fix by converting swapcontext routine to assembler.

Dave
---

--- /dev/null	2022-03-12 12:11:51.050000000 -0500
+++ sysdeps/unix/sysv/linux/hppa/swapcontext.S	2022-03-14 15:27:41.545416644 -0400
@@ -0,0 +1,72 @@
+/* Swap to new context.
+   Copyright (C) 2008-2022 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
+   <https://www.gnu.org/licenses/>.  */
+
+#include <sysdep.h>
+#include "ucontext_i.h"
+
+	.text
+ENTRY(__swapcontext)
+
+	/* Copy rp to ret0 (r28).  */
+	copy %rp,%ret0
+
+	/* Create a frame.  */
+	ldo 64(%sp),%sp
+	.cfi_def_cfa_offset -64
+
+	/* Save the current machine context to oucp.  */
+	bl __getcontext,%rp
+
+	/* Copy oucp to register ret1 (r29).  __getcontext saves and
+	   restores it on a normal return.  It is restored from oR29
+	   on reactivation.  */
+	copy %r26,%ret1
+
+	/* Pop frame.  */
+	ldo -64(%sp),%sp
+	.cfi_def_cfa_offset 0
+
+	/* Load return pointer from oR28.  */
+	ldw oR28(%ret1),%rp
+
+	/* Return if error.  */
+	or,= %r0,%ret0,%r0
+	bv,n %r0(%rp)
+
+	/* Load sc_sar flag.  */
+	ldb oSAR(%ret1),%r20
+
+	/* Return if oucp context has been reactivated.  */
+	or,= %r0,%r20,%r0
+	bv,n %r0(%rp)
+
+	/* Mark sc_sar flag.  */
+	ldi 1,%r20
+	stb %r20,oSAR(%ret1)
+
+	/* Activate the machine context in ucp.  */
+	bl __setcontext,%rp
+	ldw oR25(%ret1),%r26
+
+	/* Load return pointer.  */
+	ldw oR28(%ret1),%rp
+	bv,n %r0(%rp)
+
+PSEUDO_END(__swapcontext)
+
+weak_alias (__swapcontext, swapcontext)

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Re: [committed] hppa: Implement swapcontext in assembler (bug 28960)

[Andreas Schwab]

On Mär 15 2022, John David Anglin wrote:

> +PSEUDO_END(__swapcontext)

PSEUDO_END is supposed to pair with PSEUDO, to be used for syscalls
only.  General assembler routines should be terminated with END.

-- 
Andreas Schwab, schwab@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510  2552 DF73 E780 A9DA AEC1
"And now for something completely different."

Re: [committed] hppa: Implement swapcontext in assembler (bug 28960)

[John David Anglin]

On 2022-03-15 11:50 a.m., Andreas Schwab wrote:
> On Mär 15 2022, John David Anglin wrote:
>
>> +PSEUDO_END(__swapcontext)
> PSEUDO_END is supposed to pair with PSEUDO, to be used for syscalls
> only.  General assembler routines should be terminated with END.
Okay.   But I didn't see any issues with it in the generated .s file:

.EXIT ! .PROCEND ! .cfi_endproc ! .size __swapcontext, .-__swapcontext !

Dave

-- 
John David Anglin  dave.anglin@bell.net