[PATCH v2 2/3] perf arm64: Generate system call table from asm/unistd.h

[PATCH v2 2/3] perf arm64: Generate system call table from asm/unistd.h

[Kim Phillips]

This should speed up accessing new system calls introduced with the
kernel rather than waiting for libaudit updates to include them.

Using the existing other arch scripts resulted in this error:

tools/perf/arch/arm64/entry/syscalls//mksyscalltbl: 25: printf: __NR3264_ftruncate: expected numeric value

because, unlike other arches, asm-generic's unistd.h does things like:

 #define __NR_ftruncate __NR3264_ftruncate

Turning the scripts printf's %d into a %s resulted in this in the
generated syscalls.c file:

    static const char *syscalltbl_arm64[] = {
            [__NR3264_ftruncate] = "ftruncate",

So we use the host C compiler to fold the macros, and print them out
from within a temporary C program, in order to get the correct output:

    static const char *syscalltbl_arm64[] = {
            [46] = "ftruncate",

Cc: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Thomas Richter <tmricht@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Kim Phillips <kim.phillips@arm.com>
---
Changes in V2:
 - added the "sc" and "nr" local variables, for the sake of completion (Hendrik
   Brueckner)
 - Removed the unsafe -u from mktemp, added more X's, and now pipe the
   C code to the $hostcc command, so we now only require a single temp
   file that is written by gcc. (Hendrik Brueckner)
 - used cat << EoHEADER instead of echos for the c file header, to make it more
   readable (Hendrik Brueckner)
 - $RM -> rm, to be able to run standalone (Hendrik Brueckner)
 - moved the rm into the function that makes the file
 - converted other echos to printf "%s\n" for more portable printing of
   backslash characters (bash and dash built-in echo commands differ in
   how many escape backslashes are needed).  The initial "%s\n" is needed
   in order to keep the external printf command from interpreting the %ds.

 tools/perf/arch/arm64/Makefile                | 21 +++++++
 .../arch/arm64/entry/syscalls/mksyscalltbl    | 61 +++++++++++++++++++
 2 files changed, 82 insertions(+)
 create mode 100755 tools/perf/arch/arm64/entry/syscalls/mksyscalltbl

diff --git a/tools/perf/arch/arm64/Makefile b/tools/perf/arch/arm64/Makefile
index 91de4860faad..85fdf4949db3 100644
--- a/tools/perf/arch/arm64/Makefile
+++ b/tools/perf/arch/arm64/Makefile
@@ -4,3 +4,24 @@ PERF_HAVE_DWARF_REGS := 1
 endif
 PERF_HAVE_JITDUMP := 1
 PERF_HAVE_ARCH_REGS_QUERY_REGISTER_OFFSET := 1
+
+#
+# Syscall table generation for perf
+#
+
+out    := $(OUTPUT)arch/arm64/include/generated/asm
+header := $(out)/syscalls.c
+sysdef := $(srctree)/tools/arch/arm64/include/uapi/asm/unistd.h
+sysprf := $(srctree)/tools/perf/arch/arm64/entry/syscalls/
+systbl := $(sysprf)/mksyscalltbl
+
+# Create output directory if not already present
+_dummy := $(shell [ -d '$(out)' ] || mkdir -p '$(out)')
+
+$(header): $(sysdef) $(systbl)
+	$(Q)$(SHELL) '$(systbl)' '$(CC)' '$(HOSTCC)' $(sysdef) > $@
+
+clean::
+	$(call QUIET_CLEAN, arm64) $(RM) $(header)
+
+archheaders: $(header)
diff --git a/tools/perf/arch/arm64/entry/syscalls/mksyscalltbl b/tools/perf/arch/arm64/entry/syscalls/mksyscalltbl
new file mode 100755
index 000000000000..f806542eb3cc
--- /dev/null
+++ b/tools/perf/arch/arm64/entry/syscalls/mksyscalltbl
@@ -0,0 +1,61 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+#
+# Generate system call table for perf. Derived from
+# powerpc script.
+#
+# Copyright IBM Corp. 2017
+# Author(s):  Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
+# Changed by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
+# Changed by: Kim Phillips <kim.phillips@arm.com>
+
+gcc=$1
+hostcc=$2
+input=$3
+
+if ! test -r $input; then
+	echo "Could not read input file" >&2
+	exit 1
+fi
+
+create_table_from_c()
+{
+	local sc nr last_sc
+
+	create_table_exe=`mktemp /tmp/create-table-XXXXXX`
+
+	{
+
+cat << _EoHEADER
+#include <stdio.h>
+#include "$input"
+int main(int argc, char *argv[])
+{
+_EoHEADER
+
+	while read sc nr; do
+		printf "%s\n" "	printf(\"\\t[%d] = \\\"$sc\\\",\\n\", __NR_$sc);"
+		last_sc=$sc
+	done
+
+	printf "%s\n" "	printf(\"#define SYSCALLTBL_ARM64_MAX_ID %d\\n\", __NR_$last_sc);"
+	printf "}\n"
+
+	} | $hostcc -o $create_table_exe -x c -
+
+	$create_table_exe
+
+	rm -f $create_table_exe
+}
+
+create_table()
+{
+	echo "static const char *syscalltbl_arm64[] = {"
+	create_table_from_c
+	echo "};"
+}
+
+$gcc -E -dM -x c  $input	       \
+	|sed -ne 's/^#define __NR_//p' \
+	|sort -t' ' -k2 -nu	       \
+	|create_table
-- 
2.17.1

Re: [PATCH v2 2/3] perf arm64: Generate system call table from asm/unistd.h

[Hendrik Brueckner]

Hi Kim,

On Thu, Jul 05, 2018 at 06:12:16PM -0500, Kim Phillips wrote:
> This should speed up accessing new system calls introduced with the
> kernel rather than waiting for libaudit updates to include them.
> 
> Using the existing other arch scripts resulted in this error:
> 
> tools/perf/arch/arm64/entry/syscalls//mksyscalltbl: 25: printf: __NR3264_ftruncate: expected numeric value
> 
> because, unlike other arches, asm-generic's unistd.h does things like:
> 
>  #define __NR_ftruncate __NR3264_ftruncate
> 
> Turning the scripts printf's %d into a %s resulted in this in the
> generated syscalls.c file:
> 
>     static const char *syscalltbl_arm64[] = {
>             [__NR3264_ftruncate] = "ftruncate",
> 
> So we use the host C compiler to fold the macros, and print them out
> from within a temporary C program, in order to get the correct output:
> 
>     static const char *syscalltbl_arm64[] = {
>             [46] = "ftruncate",
> 
> Cc: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
> Cc: Jiri Olsa <jolsa@redhat.com>
> Cc: Michael Ellerman <mpe@ellerman.id.au>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Cc: Thomas Richter <tmricht@linux.vnet.ibm.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
> Signed-off-by: Kim Phillips <kim.phillips@arm.com>
> ---
> Changes in V2:
>  - added the "sc" and "nr" local variables, for the sake of completion (Hendrik
>    Brueckner)
>  - Removed the unsafe -u from mktemp, added more X's, and now pipe the
>    C code to the $hostcc command, so we now only require a single temp
>    file that is written by gcc. (Hendrik Brueckner)
>  - used cat << EoHEADER instead of echos for the c file header, to make it more
>    readable (Hendrik Brueckner)
>  - $RM -> rm, to be able to run standalone (Hendrik Brueckner)

Many thanks for incorporating the feedback!

>  - moved the rm into the function that makes the file
>  - converted other echos to printf "%s\n" for more portable printing of
>    backslash characters (bash and dash built-in echo commands differ in
>    how many escape backslashes are needed).  The initial "%s\n" is needed
>    in order to keep the external printf command from interpreting the %ds.
> 
>  tools/perf/arch/arm64/Makefile                | 21 +++++++
>  .../arch/arm64/entry/syscalls/mksyscalltbl    | 61 +++++++++++++++++++
>  2 files changed, 82 insertions(+)
>  create mode 100755 tools/perf/arch/arm64/entry/syscalls/mksyscalltbl
> 
> diff --git a/tools/perf/arch/arm64/Makefile b/tools/perf/arch/arm64/Makefile
> index 91de4860faad..85fdf4949db3 100644
> --- a/tools/perf/arch/arm64/Makefile
> +++ b/tools/perf/arch/arm64/Makefile
> @@ -4,3 +4,24 @@ PERF_HAVE_DWARF_REGS := 1
>  endif
>  PERF_HAVE_JITDUMP := 1
>  PERF_HAVE_ARCH_REGS_QUERY_REGISTER_OFFSET := 1
> +
> +#
> +# Syscall table generation for perf
> +#
> +
> +out    := $(OUTPUT)arch/arm64/include/generated/asm
> +header := $(out)/syscalls.c
> +sysdef := $(srctree)/tools/arch/arm64/include/uapi/asm/unistd.h
> +sysprf := $(srctree)/tools/perf/arch/arm64/entry/syscalls/
> +systbl := $(sysprf)/mksyscalltbl
> +
> +# Create output directory if not already present
> +_dummy := $(shell [ -d '$(out)' ] || mkdir -p '$(out)')
> +
> +$(header): $(sysdef) $(systbl)
> +	$(Q)$(SHELL) '$(systbl)' '$(CC)' '$(HOSTCC)' $(sysdef) > $@
> +
> +clean::
> +	$(call QUIET_CLEAN, arm64) $(RM) $(header)
> +
> +archheaders: $(header)
> diff --git a/tools/perf/arch/arm64/entry/syscalls/mksyscalltbl b/tools/perf/arch/arm64/entry/syscalls/mksyscalltbl
> new file mode 100755
> index 000000000000..f806542eb3cc
> --- /dev/null
> +++ b/tools/perf/arch/arm64/entry/syscalls/mksyscalltbl
> @@ -0,0 +1,61 @@
> +#!/bin/sh
> +# SPDX-License-Identifier: GPL-2.0
> +#
> +# Generate system call table for perf. Derived from
> +# powerpc script.
> +#
> +# Copyright IBM Corp. 2017
> +# Author(s):  Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
> +# Changed by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
> +# Changed by: Kim Phillips <kim.phillips@arm.com>
> +
> +gcc=$1
> +hostcc=$2
> +input=$3
> +
> +if ! test -r $input; then
> +	echo "Could not read input file" >&2
> +	exit 1
> +fi
> +
> +create_table_from_c()
> +{
> +	local sc nr last_sc
> +
> +	create_table_exe=`mktemp /tmp/create-table-XXXXXX`
> +
> +	{
> +
> +cat << _EoHEADER
> +#include <stdio.h>
> +#include "$input"
> +int main(int argc, char *argv[])
> +{
> +_EoHEADER

One minor style hint: Using cat <<-_EoHEADER (with a dash) strips any leading
tabs from the what is being concatenated.  With this, using the same indent as
for as the other function statements it possible.  For example,

	cat <<-_EoHEADER
	#include <stdio.h>
	#include "$input"
	int main(int argc, char *argv[])
	{
	_EoHEADER

> +
> +	while read sc nr; do
> +		printf "%s\n" "	printf(\"\\t[%d] = \\\"$sc\\\",\\n\", __NR_$sc);"
> +		last_sc=$sc
> +	done
> +
> +	printf "%s\n" "	printf(\"#define SYSCALLTBL_ARM64_MAX_ID %d\\n\", __NR_$last_sc);"
> +	printf "}\n"
> +
> +	} | $hostcc -o $create_table_exe -x c -
> +
> +	$create_table_exe
> +
> +	rm -f $create_table_exe
> +}
> +
> +create_table()
> +{
> +	echo "static const char *syscalltbl_arm64[] = {"
> +	create_table_from_c
> +	echo "};"
> +}
> +
> +$gcc -E -dM -x c  $input	       \
> +	|sed -ne 's/^#define __NR_//p' \
> +	|sort -t' ' -k2 -nu	       \
> +	|create_table

Overall, this looks good to me.

Reviewed-by: Hendrik Brueckner <brueckner@linux.ibm.com>