Re: [PATCH] perf arm64: Fix mksyscalltbl, don't lose syscalls due to sort -nu

[Leo Yan <leo.yan@linaro.org>]

Hi Hans-Peter,

On Mon, Dec 28, 2020 at 03:39:41AM +0100, Hans-Peter Nilsson wrote:
> When using "sort -nu", arm64 syscalls were lost.  That is, the
> io_setup syscall (number 0) and all but one (typically
> ftruncate; 64) of the syscalls that are defined symbolically
> (like "#define __NR_ftruncate __NR3264_ftruncate") at the point
> where "sort" is applied.
> 
> This creation-of-syscalls.c-scheme is, judging from comments,
> copy-pasted from powerpc, and worked there because at the time,
> its tools/arch/powerpc/include/uapi/asm/unistd.h had *literals*,
> like "#define __NR_ftruncate 93".
> 
> With sort being numeric and the non-numeric key effectively
> evaluating to 0, the sort option "-u" means these "duplicates"
> are removed.  There's no need to remove syscall lines with
> duplicate numbers for arm64 because there are none, so let's fix
> that by just losing the "-u".  Having the table numerically
> sorted on syscall-number for the rest of the syscalls looks
> nice, so keep the "-n".
> 
> Signed-off-by: Hans-Peter Nilsson <hp@axis.com>

Very good catching!  I tested this patch with the commands:

$ cd $LINUX_KERN
$ tools/perf/arch/arm64/entry/syscalls/mksyscalltbl \
        $ARM64_TOOLCHAIN_PATH/aarch64-linux-gnu-gcc \
        gcc tools tools/include/uapi/asm-generic/unistd.h

It gives out complete syscall tables:

$ diff /tmp/mksyscall_before.txt /tmp/mksyscall_after.txt
1a2,4
> 	[223] = "fadvise64",
> 	[25] = "fcntl",
> 	[44] = "fstatfs",
2a6,11
> 	[0] = "io_setup",
> 	[62] = "lseek",
> 	[222] = "mmap",
> 	[71] = "sendfile",
> 	[43] = "statfs",
> 	[45] = "truncate",

Rather than dropping option "-u" for sort command, I googled and read
the manual of "sort", but cannot find other better method.  So this
patch looks good for me:

Reviewed-by: Leo Yan <leo.yan@linaro.org>
Tested-by: Leo Yan <leo.yan@linaro.org>


> Cc: John Garry <john.garry@huawei.com>
> Cc: Will Deacon <will@kernel.org>
> Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
> Cc: Leo Yan <leo.yan@linaro.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> Cc: Jiri Olsa <jolsa@redhat.com>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Cc: Kim Phillips <kim.phillips@arm.com>
> ---
>  tools/perf/arch/arm64/entry/syscalls/mksyscalltbl | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/perf/arch/arm64/entry/syscalls/mksyscalltbl b/tools/perf/arch/arm64/entry/syscalls/mksyscalltbl
> index 459469b7222c..a7ca48d1e37b 100755
> --- a/tools/perf/arch/arm64/entry/syscalls/mksyscalltbl
> +++ b/tools/perf/arch/arm64/entry/syscalls/mksyscalltbl
> @@ -58,5 +58,5 @@ create_table()
>  
>  $gcc -E -dM -x c -I $incpath/include/uapi $input \
>  	|sed -ne 's/^#define __NR_//p' \
> -	|sort -t' ' -k2 -nu	       \
> +	|sort -t' ' -k2 -n	       \
>  	|create_table
> -- 
> 2.11.0
> 
> brgds, H-P