perf syscalltbl: Remove struct syscalltbl

The syscalltbl held entries of system call name and number pairs,
generated from a native syscalltbl at start up. As there are gaps in
the system call number there is a notion of index into the
table. Going forward we want the system call table to be identifiable
by a machine type, for example, i386 vs x86-64. Change the interface
to the syscalltbl so (1) a (currently unused machine type of EM_HOST)
is passed (2) the index to syscall number and system call name mapping
is computed at build time.

Two tables are used for this, an array of system call number to name,
an array of system call numbers sorted by the system call name. The
sorted array doesn't store strings in part to save memory and
relocations. The index notion is carried forward and is an index into
the sorted array of system call numbers, the data structures are
opaque (held only in syscalltbl.c), and so the number of indices for a
machine type is exposed as a new API.

The arrays are computed in the syscalltbl.sh script and so no start-up
time computation and storage is necessary.

Signed-off-by: Ian Rogers <irogers@google.com>
Reviewed-by: Howard Chu <howardchu95@gmail.com>
Reviewed-by: Charlie Jenkins <charlie@rivosinc.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Link: https://lore.kernel.org/r/20250319050741.269828-6-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

1 files changed, 13 insertions, 23 deletions

diff --git a/tools/perf/scripts/syscalltbl.sh b/tools/perf/scripts/syscalltbl.sh
index 1ce0d5aa8b506..a39b3013b103b 100755
--- a/tools/perf/scripts/syscalltbl.sh
+++ b/tools/perf/scripts/syscalltbl.sh
@@ -50,37 +50,27 @@ fi
 infile="$1"
 outfile="$2"
 
-nxt=0
-
-syscall_macro() {
-    nr="$1"
-    name="$2"
-
-    echo "	[$nr] = \"$name\","
-}
-
-emit() {
-    nr="$1"
-    entry="$2"
-
-    syscall_macro "$nr" "$entry"
-}
-
-echo "static const char *const syscalltbl[] = {" > $outfile
-
 sorted_table=$(mktemp /tmp/syscalltbl.XXXXXX)
 grep -E "^[0-9]+[[:space:]]+$abis" "$infile" | sort -n > $sorted_table
 
-max_nr=0
+echo "static const char *const syscall_num_to_name[] = {" > $outfile
 # the params are: nr abi name entry compat
 # use _ for intentionally unused variables according to SC2034
 while read nr _ name _ _; do
-    emit "$nr" "$name" >> $outfile
-    max_nr=$nr
+	echo "	[$nr] = \"$name\"," >> $outfile
 done < $sorted_table
+echo "};" >> $outfile
 
-rm -f $sorted_table
+echo "static const uint16_t syscall_sorted_names[] = {" >> $outfile
 
+# When sorting by name, add a suffix of 0s upto 20 characters so that system
+# calls that differ with a numerical suffix don't sort before those
+# without. This default behavior of sort differs from that of strcmp used at
+# runtime. Use sed to strip the trailing 0s suffix afterwards.
+grep -E "^[0-9]+[[:space:]]+$abis" "$infile" | awk '{printf $3; for (i = length($3); i < 20; i++) { printf "0"; }; print " " $1}'| sort | sed 's/\([a-zA-Z1-9]\+\)0\+ \([0-9]\+\)/\1 \2/' > $sorted_table
+while read name nr; do
+	echo "	$nr,	/* $name */" >> $outfile
+done < $sorted_table
 echo "};" >> $outfile
 
-echo "#define SYSCALLTBL_MAX_ID ${max_nr}" >> $outfile
+rm -f $sorted_table