Re: [PATCH][SPARC] Fix single-stepping in syscalls other than sigreturn

[Mark Kettenis <mark dot kettenis at xs4all dot nl>]

> From: jose.marchesi@oracle.com (Jose E. Marchesi)
> Date: Wed, 29 Jan 2014 16:06:28 +0100
> 
> [Continuing http://sourceware.org/ml/gdb-patches/2013-09/msg00817.html]
> 
> Improved patch including a testcase and also some minor changes in the
> changelog entry.
> 
> 2014-01-29  Jose E. Marchesi  <jose.marchesi@oracle.com>
> 
> 	* sparc64-linux-tdep.c (sparc64_linux_step_trap): Get PC from
>           the sigreturn register save area only if the syscall is
>           sigreturn.
> 
> 2014-01-29  Jose E. Marchesi  <jose.marchesi@oracle.com>
> 
> 	* gdb.arch/sparc-sysstep.exp: New file.
> 	* gdb.arch/sparc-sysstep.c: Likewise.
> 
> 	* gdb.arch/Makefile.in (EXECUTABLES): Add sparc-sysstep.

Having a test case is good!

Given that David Miller hasn't objected, feel free to go ahead and
commit this.

> diff --git a/gdb/sparc64-linux-tdep.c b/gdb/sparc64-linux-tdep.c
> index ea83c28..a381d2a 100644
> --- a/gdb/sparc64-linux-tdep.c
> +++ b/gdb/sparc64-linux-tdep.c
> @@ -111,7 +111,9 @@ sparc64_linux_sigframe_init (const struct tramp_frame *self,
>  static CORE_ADDR
>  sparc64_linux_step_trap (struct frame_info *frame, unsigned long insn)
>  {
> -  if (insn == 0x91d0206d)
> +  /* __NR_rt_sigreturn is 101  */
> +  if ((insn == 0x91d0206d)
> +      && (get_frame_register_unsigned (frame, SPARC_G1_REGNUM) == 101))
>      {
>        struct gdbarch *gdbarch = get_frame_arch (frame);
>        enum bfd_endian byte_order = gdbarch_byte_order (gdbarch);
> diff --git a/gdb/testsuite/gdb.arch/Makefile.in b/gdb/testsuite/gdb.arch/Makefile.in
> index e5f8934..658c7ad 100644
> --- a/gdb/testsuite/gdb.arch/Makefile.in
> +++ b/gdb/testsuite/gdb.arch/Makefile.in
> @@ -3,7 +3,7 @@ srcdir = @srcdir@
>  
>  EXECUTABLES = altivec-abi altivec-regs amd64-byte amd64-disp-step amd64-dword \
>  	amd64-entry-value amd64-i386-address amd64-word i386-bp_permanent \
> -	i386-permbkpt i386-avx i386-signal i386-sse
> +	i386-permbkpt i386-avx i386-signal i386-sse sparc-sysstep
>  
>  all info install-info dvi install uninstall installcheck check:
>  	@echo "Nothing to be done for $@..."
> diff --git a/gdb/testsuite/gdb.arch/sparc-sysstep.c b/gdb/testsuite/gdb.arch/sparc-sysstep.c
> new file mode 100644
> index 0000000..911fcbd
> --- /dev/null
> +++ b/gdb/testsuite/gdb.arch/sparc-sysstep.c
> @@ -0,0 +1,35 @@
> +/* Test single-stepping system call instructions in sparc.
> +
> +   Copyright 2014 Free Software Foundation, Inc.
> +
> +   This file is part of GDB.
> +
> +   This program is free software; you can redistribute it and/or modify
> +   it under the terms of the GNU General Public License as published by
> +   the Free Software Foundation; either version 3 of the License, or
> +   (at your option) any later version.
> +
> +   This program 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 General Public License for more details.
> +
> +   You should have received a copy of the GNU General Public License
> +   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
> +
> +#include <signal.h>
> +
> +int global;
> +
> +static void
> +handler (int sig)
> +{
> +}
> +
> +int
> +main ()
> +{
> +  signal (SIGALRM, handler);
> +  kill (getpid (), SIGALRM);
> +  return 0; /* sparc-sysstep.exp: last */
> +}
> diff --git a/gdb/testsuite/gdb.arch/sparc-sysstep.exp b/gdb/testsuite/gdb.arch/sparc-sysstep.exp
> new file mode 100644
> index 0000000..ac840f5
> --- /dev/null
> +++ b/gdb/testsuite/gdb.arch/sparc-sysstep.exp
> @@ -0,0 +1,48 @@
> +# Copyright 2014 Free Software Foundation, Inc.
> +#
> +# This program is free software; you can redistribute it and/or modify
> +# it under the terms of the GNU General Public License as published by
> +# the Free Software Foundation; either version 3 of the License, or
> +# (at your option) any later version.
> +#
> +# This program 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 General Public License for more details.
> +#
> +# You should have received a copy of the GNU General Public License
> +# along with this program.  If not, see <http://www.gnu.org/licenses/>.
> +#
> +# This file is part of the gdb testsuite.
> +
> +# Test single-stepping system call instructions (ta 0x6d) in the two
> +# cases distinguished by the implementation: sigreturn and all others.
> +# The sigreturn syscall requires a special analysis since the return
> +# PC must be extracted from the sigreturn register save area in the
> +# stack.
> +
> +if ![istarget "sparc*-*-linux*"] then {
> +    return 0
> +}
> +
> +set testfile sparc-sysstep
> +set srcfile ${testfile}.c
> +set binfile ${objdir}/${subdir}/${testfile}
> +
> +if {[prepare_for_testing ${testfile}.exp ${binfile} $srcfile {additional_flags=-g}]} {
> +    return -1
> +}
> +
> +if ![runto_main] {
> +    return -1
> +}
> +
> +# Watching the global variable will guarantee that gdb will
> +# single-step through the whole program.
> +
> +set lno [gdb_get_line_number "sparc-sysstep.exp: last" $srcfile]
> +
> +gdb_test "break $srcfile:$lno" "Breakpoint \[0-9\] at .*"
> +gdb_test_no_output "set can-use-hw-watchpoints 0" ""
> +gdb_test "watch global" "Watchpoint .*: global"
> +gdb_test "continue" "Continuing.*${srcfile}:${lno}.*"
>