linux-kernel - [PATCH v2 2/8] scripts/syscalltbl.sh: add optional --used-syscalls argument for syscall trimming

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Message-ID: <B120EFEBD27B9B67+6751ec7c12d04aafe1de79502b984ed65013f6cf.1760463245.git.tanyuan@tinylab.org>
Date: Wed, 15 Oct 2025 14:17:49 +0800
From: Yuan Tan <tanyuan@...ylab.org>
To: arnd@...db.de,
	masahiroy@...nel.org,
	nathan@...nel.org,
	palmer@...belt.com,
	linux-kbuild@...r.kernel.org,
	linux-riscv@...ts.infradead.org
Cc: linux-arch@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	i@...kray.me,
	tanyuan@...ylab.org,
	falcon@...ylab.org,
	ronbogo@...look.com,
	z1652074432@...il.com,
	lx24@....ynu.edu.cn
Subject: [PATCH v2 2/8] scripts/syscalltbl.sh: add optional --used-syscalls argument for syscall trimming

From: Yuhang Zheng <z1652074432@...il.com>

Add support for an optional `--used-syscalls` argument to
scripts/syscalltbl.sh. When provided, the argument takes a comma-separated
list of syscall names that should remain enabled in the generated syscall
table. Any syscall not present in the list will be replaced with a
`__SYSCALL(nr, sys_ni_syscall)` entry.

This enables selective system call table generation when
CONFIG_TRIM_UNUSED_SYSCALLS is set.

Signed-off-by: Yuhang Zheng <z1652074432@...il.com>
Signed-off-by: Yuan Tan <tanyuan@...ylab.org>
Signed-off-by: Zhangjin Wu <falcon@...ylab.org>
---
 scripts/syscalltbl.sh | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/scripts/syscalltbl.sh b/scripts/syscalltbl.sh
index 6a903b87a7c2..27d8dfce5748 100755
--- a/scripts/syscalltbl.sh
+++ b/scripts/syscalltbl.sh
@@ -22,12 +22,14 @@ usage() {
 	echo >&2 "  OUTFILE   output header file"
 	echo >&2
 	echo >&2 "options:"
-	echo >&2 "  --abis ABIS        ABI(s) to handle (By default, all lines are handled)"
+	echo >&2 "  --abis ABIS                ABI(s) to handle (By default, all lines are handled)"
+	echo >&2 "  --used-syscalls SYSCALLS   Keep only the specified syscall; trim others"
 	exit 1
 }
 
 # default unless specified by options
 abis=
+used_syscalls=
 
 while [ $# -gt 0 ]
 do
@@ -35,6 +37,14 @@ do
 	--abis)
 		abis=$(echo "($2)" | tr ',' '|')
 		shift 2;;
+    --used-syscalls=*)
+        used_syscalls_raw=${1#--used-syscalls=}
+        if [ -z "$used_syscalls_raw" ]; then
+            used_syscalls='^$'
+        else
+            used_syscalls=$(echo "$used_syscalls_raw" | tr ',' '|')
+        fi
+        shift;;
 	-*)
 		echo "$1: unknown option" >&2
 		usage;;
@@ -52,6 +62,7 @@ outfile="$2"
 
 nxt=0
 
+
 grep -E "^[0-9]+[[:space:]]+$abis" "$infile" | {
 
 	while read nr abi name native compat noreturn; do
@@ -66,6 +77,12 @@ grep -E "^[0-9]+[[:space:]]+$abis" "$infile" | {
 			nxt=$((nxt + 1))
 		done
 
+		if [ -n "$used_syscalls" ] && ! echo "$name" | grep -qwE "$used_syscalls"; then
+			echo "__SYSCALL($nr, sys_ni_syscall)"
+			nxt=$((nr + 1))
+			continue
+		fi
+
 		if [ "$compat" = "-" ]; then
 			unset compat
 		fi
-- 
2.43.0