[PATCH RFC 0/4] syscalls: Add a shared table for all archs

[PATCH RFC 0/4] syscalls: Add a shared table for all archs

[André Almeida]

While implementing a new syscall, we need to wire up it's number to the arch
table. Since syscall number 403, all architectures are on sync regarding the
number (except alpha), which make things a lot easier but more repetitive as
well. Have a look at commit b36d4b6aa88 ("arch: hookup listns() system call"),
with 15 lines of mostly:

  +470    common  listns                          sys_listns

There's already a "common" table shared with a bunch of archs at
`scripts/syscall.tbl`, but due to historical reasons some archs will never be
able to move to this table and share all the numbers.

In order to make things a bit easier, this patchset creates yet another common
syscall table with a subset of numbers that are already being shared among the
syscalls. I've started from syscall 442 (mount_setattr) to avoid dealing with
compat syscalls for now, but this already have the benefit of adding or rebasing
a new syscall much easier. If this work sounds reasonable I can later add more
syscalls, removing more repetitive lines from the code.

I've tested this with x86 and arm64, by comparing the syscalls_*.h and
unistd_*.h files generated before and after this patchset and they are
identical.

Thanks!
	André

---
André Almeida (4):
      syscalls: Create unified partial table for all archs
      syscalls: Add support for x86_x32 for the common syscall table
      x86: Use common syscall table
      scripts/syscall.tbl: Use the common table

 arch/arm64/tools/syscall_32.tbl        | 30 -------------
 arch/x86/entry/syscalls/Makefile       | 15 ++++---
 arch/x86/entry/syscalls/syscall_32.tbl | 30 -------------
 arch/x86/entry/syscalls/syscall_64.tbl | 30 -------------
 scripts/Makefile.asm-headers           |  4 +-
 scripts/syscall.tbl                    | 30 -------------
 scripts/syscall_common.tbl             | 34 ++++++++++++++
 scripts/syscallhdr.sh                  | 81 +++++++++++++++++++++++++++++-----
 scripts/syscalltbl.sh                  | 26 ++++++++---
 9 files changed, 134 insertions(+), 146 deletions(-)
---
base-commit: af5e34a41cd607c00ef752e00331736570992354
change-id: 20260724-tonyk-syscall_table-928bbb1b26bb

Best regards,
--  
André Almeida <andrealmeid@igalia.com>

[PATCH RFC 1/4] syscalls: Create unified partial table for all archs

[André Almeida]

To take advantage of the subset of syscall numbers that are guaranteed to
be shared, create a new table and adapt generation scripts to use it. In
that way, every new syscall can be added to a single file.

Signed-off-by: André Almeida <andrealmeid@igalia.com>
---
 scripts/syscall_common.tbl | 34 ++++++++++++++++++++++++++++
 scripts/syscallhdr.sh      | 55 +++++++++++++++++++++++++++++++++++-----------
 scripts/syscalltbl.sh      | 26 +++++++++++++++++-----
 3 files changed, 97 insertions(+), 18 deletions(-)

diff --git a/scripts/syscall_common.tbl b/scripts/syscall_common.tbl
new file mode 100644
index 000000000000..97ea46ea8d56
--- /dev/null
+++ b/scripts/syscall_common.tbl
@@ -0,0 +1,34 @@
+# SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note
+#
+# syscall numbers shared by architectures
+
+442	common	mount_setattr			sys_mount_setattr
+443	common	quotactl_fd			sys_quotactl_fd
+444	common	landlock_create_ruleset		sys_landlock_create_ruleset
+445	common	landlock_add_rule		sys_landlock_add_rule
+446	common	landlock_restrict_self		sys_landlock_restrict_self
+447	memfd_secret	memfd_secret			sys_memfd_secret
+448	common	process_mrelease		sys_process_mrelease
+449	common	futex_waitv			sys_futex_waitv
+450	common	set_mempolicy_home_node		sys_set_mempolicy_home_node
+451	common	cachestat			sys_cachestat
+452	common	fchmodat2			sys_fchmodat2
+453	common	map_shadow_stack		sys_map_shadow_stack
+454	common	futex_wake			sys_futex_wake
+455	common	futex_wait			sys_futex_wait
+456	common	futex_requeue			sys_futex_requeue
+457	common	statmount			sys_statmount
+458	common	listmount			sys_listmount
+459	common	lsm_get_self_attr		sys_lsm_get_self_attr
+460	common	lsm_set_self_attr		sys_lsm_set_self_attr
+461	common	lsm_list_modules		sys_lsm_list_modules
+462	common	mseal				sys_mseal
+463	common	setxattrat			sys_setxattrat
+464	common	getxattrat			sys_getxattrat
+465	common	listxattrat			sys_listxattrat
+466	common	removexattrat			sys_removexattrat
+467	common	open_tree_attr			sys_open_tree_attr
+468	common	file_getattr			sys_file_getattr
+469	common	file_setattr			sys_file_setattr
+470	common	listns				sys_listns
+471	common	rseq_slice_yield		sys_rseq_slice_yield
diff --git a/scripts/syscallhdr.sh b/scripts/syscallhdr.sh
index 22e34cd46b9b..77934a2d0f51 100755
--- a/scripts/syscallhdr.sh
+++ b/scripts/syscallhdr.sh
@@ -26,6 +26,7 @@ usage() {
 	echo >&2 "  --emit-nr          Emit the macro of the number of syscalls (__NR_syscalls)"
 	echo >&2 "  --offset OFFSET    The offset of syscall numbers"
 	echo >&2 "  --prefix PREFIX    The prefix to the macro like __NR_<PREFIX><NAME>"
+	echo >&2 "  --common-tbl       Use the common number table"
 	exit 1
 }
 
@@ -34,6 +35,9 @@ abis=
 emit_nr=
 offset=
 prefix=
+common_tbl=
+max=0
+COMMON_TBL_PATH="../scripts/syscall_common.tbl"
 
 while [ $# -gt 0 ]
 do
@@ -50,6 +54,9 @@ do
 	--prefix)
 		prefix=$2
 		shift 2;;
+	--common-tbl)
+		common_tbl=1
+		shift 1;;
 	-*)
 		echo "$1: unknown option" >&2
 		usage;;
@@ -69,13 +76,32 @@ guard=_UAPI_ASM_$(basename "$outfile" |
 	sed -e 'y/abcdefghijklmnopqrstuvwxyz/ABCDEFGHIJKLMNOPQRSTUVWXYZ/' \
 	-e 's/[^A-Z0-9_]/_/g' -e 's/__/_/g')
 
-grep -E "^[0-9A-Fa-fXx]+[[:space:]]+$abis" "$infile" | {
+emit_start_guard() {
 	echo "#ifndef $guard"
 	echo "#define $guard"
 	echo
+}
+
+# emit_nr(prefix, nr)
+emit_nr() {
+	local nr=$1
+	local prefix=$2
+	echo
+	echo "#ifdef __KERNEL__"
+	echo "#define __NR_${prefix}syscalls $nr"
+	echo "#endif"
+}
+
+emit_end_guard() {
+	echo
+	echo "#endif /* $guard */"
+}
 
-	max=0
-	while read nr abi name native compat ; do
+# gen_hdr(infile)
+gen_hdr() {
+	input=$1
+
+	while read nr abi name native compat; do
 
 		max=$nr
 
@@ -84,15 +110,18 @@ grep -E "^[0-9A-Fa-fXx]+[[:space:]]+$abis" "$infile" | {
 		fi
 
 		echo "#define __NR_$prefix$name $nr"
-	done
 
-	if [ -n "$emit_nr" ]; then
-		echo
-		echo "#ifdef __KERNEL__"
-		echo "#define __NR_${prefix}syscalls $(($max + 1))"
-		echo "#endif"
-	fi
+	done < <(grep -E "^[0-9A-Fa-fXx]+[[:space:]]+$abis" "$input")
+}
 
-	echo
-	echo "#endif /* $guard */"
-} > "$outfile"
+emit_start_guard > $outfile
+
+gen_hdr $infile >> $outfile
+
+if [ -n "$common_tbl" ]; then
+	gen_hdr $COMMON_TBL_PATH  >> "$outfile"
+fi
+
+emit_nr $(($max + 1)) $prefix >> $outfile
+
+emit_end_guard >> $outfile
diff --git a/scripts/syscalltbl.sh b/scripts/syscalltbl.sh
index 6a903b87a7c2..30441cf88ead 100755
--- a/scripts/syscalltbl.sh
+++ b/scripts/syscalltbl.sh
@@ -23,11 +23,14 @@ usage() {
 	echo >&2
 	echo >&2 "options:"
 	echo >&2 "  --abis ABIS        ABI(s) to handle (By default, all lines are handled)"
+	echo >&2 "  --common-tbl       Use the common syscall number table"
 	exit 1
 }
 
 # default unless specified by options
 abis=
+common_tbl=
+COMMON_TBL_PATH="../scripts/syscall_common.tbl"
 
 while [ $# -gt 0 ]
 do
@@ -35,6 +38,9 @@ do
 	--abis)
 		abis=$(echo "($2)" | tr ',' '|')
 		shift 2;;
+	--common-tbl)
+		common_tbl=1
+		shift 1;;
 	-*)
 		echo "$1: unknown option" >&2
 		usage;;
@@ -52,12 +58,14 @@ outfile="$2"
 
 nxt=0
 
-grep -E "^[0-9]+[[:space:]]+$abis" "$infile" | {
+# gen_tbl(infile)
+gen_tbl() {
+	input=$1
 
 	while read nr abi name native compat noreturn; do
 
 		if [ $nxt -gt $nr ]; then
-			echo "error: $infile: syscall table is not sorted or duplicates the same syscall number" >&2
+			echo "error: $input: syscall table is not sorted or duplicates the same syscall number" >&2
 			exit 1
 		fi
 
@@ -72,7 +80,7 @@ grep -E "^[0-9]+[[:space:]]+$abis" "$infile" | {
 
 		if [ -n "$noreturn" ]; then
 			if [ "$noreturn" != "noreturn" ]; then
-				echo "error: $infile: invalid string \"$noreturn\" in 'noreturn' column"
+				echo "error: $input: invalid string \"$noreturn\" in 'noreturn' column"
 				exit 1
 			fi
 			if [ -n "$compat" ]; then
@@ -88,5 +96,13 @@ grep -E "^[0-9]+[[:space:]]+$abis" "$infile" | {
 			echo "__SYSCALL($nr, sys_ni_syscall)"
 		fi
 		nxt=$((nr + 1))
-	done
-} > "$outfile"
+
+	done < <(grep -E "^[0-9]+[[:space:]]+$abis" "$input")
+
+}
+
+gen_tbl $infile  > "$outfile"
+
+if [ -n "$common_tbl" ]; then
+	gen_tbl $COMMON_TBL_PATH >> "$outfile"
+fi

-- 
2.55.0

[PATCH RFC 2/4] syscalls: Add support for x86_x32 for the common syscall table

[André Almeida]

x86_x32 has a peculiar ordering: first, goes the x86 syscalls. Then, the
shared syscall numbers from the common table, and finally the x86_x32
syscall numbers. Adapt syscallhdr.sh script to take this into account.

Let's hope that x32 is deprecated before the syscall table reaches syscall
512, to avoid making the shared table more confusing.

Signed-off-by: André Almeida <andrealmeid@igalia.com>
---
 scripts/syscallhdr.sh | 34 +++++++++++++++++++++++++++++++---
 1 file changed, 31 insertions(+), 3 deletions(-)

diff --git a/scripts/syscallhdr.sh b/scripts/syscallhdr.sh
index 77934a2d0f51..b68492946d6f 100755
--- a/scripts/syscallhdr.sh
+++ b/scripts/syscallhdr.sh
@@ -72,6 +72,12 @@ fi
 infile="$1"
 outfile="$2"
 
+is_x32=
+
+if [[ "$abis" == *"x32"* ]]; then
+	is_x32=1
+fi
+
 guard=_UAPI_ASM_$(basename "$outfile" |
 	sed -e 'y/abcdefghijklmnopqrstuvwxyz/ABCDEFGHIJKLMNOPQRSTUVWXYZ/' \
 	-e 's/[^A-Z0-9_]/_/g' -e 's/__/_/g')
@@ -116,10 +122,32 @@ gen_hdr() {
 
 emit_start_guard > $outfile
 
-gen_hdr $infile >> $outfile
+# x32 has a special ordering. We need to get first the common numbers from x86
+# table, then the common numbers from scripts/syscall_common.tbl and finally the
+# x32 numbers
+if [ -n "$is_x32" ]; then
+
+	abis="${abis//x32|/}"
+	abis="${abis//|x32/}"
+	abis="${abis//x32/}"
+
+	if [[ $abis != "()" ]]; then
+		gen_hdr $infile >> $outfile
+
+		if [ -n "$common_tbl" ]; then
+			gen_hdr $COMMON_TBL_PATH  >> "$outfile"
+		fi
+	fi
+
+	abis="(x32)"
+
+	gen_hdr $infile >> "$outfile"
+else
+	gen_hdr $infile >> $outfile
 
-if [ -n "$common_tbl" ]; then
-	gen_hdr $COMMON_TBL_PATH  >> "$outfile"
+	if [ -n "$common_tbl" ]; then
+		gen_hdr $COMMON_TBL_PATH  >> "$outfile"
+	fi
 fi
 
 emit_nr $(($max + 1)) $prefix >> $outfile

-- 
2.55.0

[PATCH RFC 3/4] x86: Use common syscall table

[André Almeida]

Use common syscall table and drop the shared numbers from the x86 tables.

Signed-off-by: André Almeida <andrealmeid@igalia.com>
---
 arch/x86/entry/syscalls/Makefile       | 15 ++++++++-------
 arch/x86/entry/syscalls/syscall_32.tbl | 30 ------------------------------
 arch/x86/entry/syscalls/syscall_64.tbl | 30 ------------------------------
 3 files changed, 8 insertions(+), 67 deletions(-)

diff --git a/arch/x86/entry/syscalls/Makefile b/arch/x86/entry/syscalls/Makefile
index eca5d6eff132..f4bdad7fea13 100644
--- a/arch/x86/entry/syscalls/Makefile
+++ b/arch/x86/entry/syscalls/Makefile
@@ -15,30 +15,31 @@ prefix :=
 
 quiet_cmd_syshdr = SYSHDR  $@
       cmd_syshdr = $(CONFIG_SHELL) $(syshdr) --abis $(abis) --emit-nr \
+      		--common-tbl \
 		$(if $(offset),--offset $(offset)) \
 		$(if $(prefix),--prefix $(prefix)) \
 		$< $@
 quiet_cmd_systbl = SYSTBL  $@
-      cmd_systbl = $(CONFIG_SHELL) $(systbl) --abis $(abis) $< $@
+      cmd_systbl = $(CONFIG_SHELL) $(systbl) --abis $(abis) --common-tbl $< $@
 
 quiet_cmd_hypercalls = HYPERCALLS $@
       cmd_hypercalls = $(CONFIG_SHELL) '$<' $@ $(filter-out $<, $(real-prereqs))
 
-$(uapi)/unistd_32.h: abis := i386
+$(uapi)/unistd_32.h: abis := common,i386,memfd_secret
 $(uapi)/unistd_32.h: $(syscall32) $(syshdr) FORCE
 	$(call if_changed,syshdr)
 
-$(out)/unistd_32_ia32.h: abis := i386
+$(out)/unistd_32_ia32.h: abis := common,i386,memfd_secret
 $(out)/unistd_32_ia32.h: prefix := ia32_
 $(out)/unistd_32_ia32.h: $(syscall32) $(syshdr) FORCE
 	$(call if_changed,syshdr)
 
-$(uapi)/unistd_x32.h: abis := common,x32
+$(uapi)/unistd_x32.h: abis := common,x32,memfd_secret
 $(uapi)/unistd_x32.h: offset := __X32_SYSCALL_BIT
 $(uapi)/unistd_x32.h: $(syscall64) $(syshdr) FORCE
 	$(call if_changed,syshdr)
 
-$(uapi)/unistd_64.h: abis := common,64
+$(uapi)/unistd_64.h: abis := common,64,memfd_secret
 $(uapi)/unistd_64.h: $(syscall64) $(syshdr) FORCE
 	$(call if_changed,syshdr)
 
@@ -47,10 +48,10 @@ $(out)/unistd_64_x32.h: prefix := x32_
 $(out)/unistd_64_x32.h: $(syscall64) $(syshdr) FORCE
 	$(call if_changed,syshdr)
 
-$(out)/syscalls_32.h: abis := i386
+$(out)/syscalls_32.h: abis := common,i386,memfd_secret
 $(out)/syscalls_32.h: $(syscall32) $(systbl) FORCE
 	$(call if_changed,systbl)
-$(out)/syscalls_64.h: abis := common,64
+$(out)/syscalls_64.h: abis := common,64,memfd_secret
 $(out)/syscalls_64.h: $(syscall64) $(systbl) FORCE
 	$(call if_changed,systbl)
 $(out)/syscalls_x32.h: abis := common,x32
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index f832ebd2d79b..77678941163d 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -447,33 +447,3 @@
 439	i386	faccessat2		sys_faccessat2
 440	i386	process_madvise		sys_process_madvise
 441	i386	epoll_pwait2		sys_epoll_pwait2		compat_sys_epoll_pwait2
-442	i386	mount_setattr		sys_mount_setattr
-443	i386	quotactl_fd		sys_quotactl_fd
-444	i386	landlock_create_ruleset	sys_landlock_create_ruleset
-445	i386	landlock_add_rule	sys_landlock_add_rule
-446	i386	landlock_restrict_self	sys_landlock_restrict_self
-447	i386	memfd_secret		sys_memfd_secret
-448	i386	process_mrelease	sys_process_mrelease
-449	i386	futex_waitv		sys_futex_waitv
-450	i386	set_mempolicy_home_node		sys_set_mempolicy_home_node
-451	i386	cachestat		sys_cachestat
-452	i386	fchmodat2		sys_fchmodat2
-453	i386	map_shadow_stack	sys_map_shadow_stack
-454	i386	futex_wake		sys_futex_wake
-455	i386	futex_wait		sys_futex_wait
-456	i386	futex_requeue		sys_futex_requeue
-457	i386	statmount		sys_statmount
-458	i386	listmount		sys_listmount
-459	i386	lsm_get_self_attr	sys_lsm_get_self_attr
-460	i386	lsm_set_self_attr	sys_lsm_set_self_attr
-461	i386	lsm_list_modules	sys_lsm_list_modules
-462	i386	mseal 			sys_mseal
-463	i386	setxattrat		sys_setxattrat
-464	i386	getxattrat		sys_getxattrat
-465	i386	listxattrat		sys_listxattrat
-466	i386	removexattrat		sys_removexattrat
-467	i386	open_tree_attr		sys_open_tree_attr
-468	i386	file_getattr		sys_file_getattr
-469	i386	file_setattr		sys_file_setattr
-470	i386	listns			sys_listns
-471	i386	rseq_slice_yield	sys_rseq_slice_yield
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index 524155d655da..915aa5a78132 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -366,36 +366,6 @@
 439	common	faccessat2		sys_faccessat2
 440	common	process_madvise		sys_process_madvise
 441	common	epoll_pwait2		sys_epoll_pwait2
-442	common	mount_setattr		sys_mount_setattr
-443	common	quotactl_fd		sys_quotactl_fd
-444	common	landlock_create_ruleset	sys_landlock_create_ruleset
-445	common	landlock_add_rule	sys_landlock_add_rule
-446	common	landlock_restrict_self	sys_landlock_restrict_self
-447	common	memfd_secret		sys_memfd_secret
-448	common	process_mrelease	sys_process_mrelease
-449	common	futex_waitv		sys_futex_waitv
-450	common	set_mempolicy_home_node	sys_set_mempolicy_home_node
-451	common	cachestat		sys_cachestat
-452	common	fchmodat2		sys_fchmodat2
-453	common	map_shadow_stack	sys_map_shadow_stack
-454	common	futex_wake		sys_futex_wake
-455	common	futex_wait		sys_futex_wait
-456	common	futex_requeue		sys_futex_requeue
-457	common	statmount		sys_statmount
-458	common	listmount		sys_listmount
-459	common	lsm_get_self_attr	sys_lsm_get_self_attr
-460	common	lsm_set_self_attr	sys_lsm_set_self_attr
-461	common	lsm_list_modules	sys_lsm_list_modules
-462 	common  mseal			sys_mseal
-463	common	setxattrat		sys_setxattrat
-464	common	getxattrat		sys_getxattrat
-465	common	listxattrat		sys_listxattrat
-466	common	removexattrat		sys_removexattrat
-467	common	open_tree_attr		sys_open_tree_attr
-468	common	file_getattr		sys_file_getattr
-469	common	file_setattr		sys_file_setattr
-470	common	listns			sys_listns
-471	common	rseq_slice_yield	sys_rseq_slice_yield
 
 #
 # Due to a historical design error, certain syscalls are numbered differently

-- 
2.55.0

[PATCH RFC 4/4] scripts/syscall.tbl: Use the common table

[André Almeida]

Use the common syscall number table and drop the shared numbers from the
table.

Signed-off-by: André Almeida <andrealmeid@igalia.com>
---
 arch/arm64/tools/syscall_32.tbl | 30 ------------------------------
 scripts/Makefile.asm-headers    |  4 ++--
 scripts/syscall.tbl             | 30 ------------------------------
 3 files changed, 2 insertions(+), 62 deletions(-)

diff --git a/arch/arm64/tools/syscall_32.tbl b/arch/arm64/tools/syscall_32.tbl
index 62d93d88e0fe..98315dee6d0b 100644
--- a/arch/arm64/tools/syscall_32.tbl
+++ b/arch/arm64/tools/syscall_32.tbl
@@ -453,33 +453,3 @@
 439	common	faccessat2			sys_faccessat2
 440	common	process_madvise			sys_process_madvise
 441	common	epoll_pwait2			sys_epoll_pwait2		compat_sys_epoll_pwait2
-442	common	mount_setattr			sys_mount_setattr
-443	common	quotactl_fd			sys_quotactl_fd
-444	common	landlock_create_ruleset		sys_landlock_create_ruleset
-445	common	landlock_add_rule		sys_landlock_add_rule
-446	common	landlock_restrict_self		sys_landlock_restrict_self
-# 447 reserved for memfd_secret
-448	common	process_mrelease		sys_process_mrelease
-449	common	futex_waitv			sys_futex_waitv
-450	common	set_mempolicy_home_node		sys_set_mempolicy_home_node
-451	common	cachestat			sys_cachestat
-452	common	fchmodat2			sys_fchmodat2
-453	common	map_shadow_stack		sys_map_shadow_stack
-454	common	futex_wake			sys_futex_wake
-455	common	futex_wait			sys_futex_wait
-456	common	futex_requeue			sys_futex_requeue
-457	common	statmount			sys_statmount
-458	common	listmount			sys_listmount
-459	common	lsm_get_self_attr		sys_lsm_get_self_attr
-460	common	lsm_set_self_attr		sys_lsm_set_self_attr
-461	common	lsm_list_modules		sys_lsm_list_modules
-462	common	mseal				sys_mseal
-463	common	setxattrat			sys_setxattrat
-464	common	getxattrat			sys_getxattrat
-465	common	listxattrat			sys_listxattrat
-466	common	removexattrat			sys_removexattrat
-467	common	open_tree_attr			sys_open_tree_attr
-468	common	file_getattr			sys_file_getattr
-469	common	file_setattr			sys_file_setattr
-470	common	listns				sys_listns
-471	common	rseq_slice_yield		sys_rseq_slice_yield
diff --git a/scripts/Makefile.asm-headers b/scripts/Makefile.asm-headers
index 8a4856e74180..995171dab2ca 100644
--- a/scripts/Makefile.asm-headers
+++ b/scripts/Makefile.asm-headers
@@ -58,14 +58,14 @@ quiet_cmd_remove = REMOVE  $(unwanted)
       cmd_remove = rm -f $(unwanted)
 
 quiet_cmd_syshdr = SYSHDR  $@
-      cmd_syshdr = $(CONFIG_SHELL) $(syshdr) \
+      cmd_syshdr = $(CONFIG_SHELL) $(syshdr) --common-tbl \
 		   $(if $(syshdr-args-$*),$(syshdr-args-$*),$(syshdr-args)) \
 		   $(if $(syscall_compat),--prefix "compat$*_") \
 		   --abis $(subst $(space),$(comma),$(strip $(syscall_abis_$*))) \
 		   $< $@
 
 quiet_cmd_systbl = SYSTBL  $@
-      cmd_systbl = $(CONFIG_SHELL) $(systbl) \
+      cmd_systbl = $(CONFIG_SHELL) $(systbl) --common-tbl \
 		   $(if $(systbl-args-$*),$(systbl-args-$*),$(systbl-args)) \
 		   --abis $(subst $(space),$(comma),$(strip $(syscall_abis_$*))) \
 		   $< $@
diff --git a/scripts/syscall.tbl b/scripts/syscall.tbl
index 7a42b32b6577..8f0c4a1678d7 100644
--- a/scripts/syscall.tbl
+++ b/scripts/syscall.tbl
@@ -382,33 +382,3 @@
 439	common	faccessat2			sys_faccessat2
 440	common	process_madvise			sys_process_madvise
 441	common	epoll_pwait2			sys_epoll_pwait2		compat_sys_epoll_pwait2
-442	common	mount_setattr			sys_mount_setattr
-443	common	quotactl_fd			sys_quotactl_fd
-444	common	landlock_create_ruleset		sys_landlock_create_ruleset
-445	common	landlock_add_rule		sys_landlock_add_rule
-446	common	landlock_restrict_self		sys_landlock_restrict_self
-447	memfd_secret	memfd_secret		sys_memfd_secret
-448	common	process_mrelease		sys_process_mrelease
-449	common	futex_waitv			sys_futex_waitv
-450	common	set_mempolicy_home_node		sys_set_mempolicy_home_node
-451	common	cachestat			sys_cachestat
-452	common	fchmodat2			sys_fchmodat2
-453	common	map_shadow_stack		sys_map_shadow_stack
-454	common	futex_wake			sys_futex_wake
-455	common	futex_wait			sys_futex_wait
-456	common	futex_requeue			sys_futex_requeue
-457	common	statmount			sys_statmount
-458	common	listmount			sys_listmount
-459	common	lsm_get_self_attr		sys_lsm_get_self_attr
-460	common	lsm_set_self_attr		sys_lsm_set_self_attr
-461	common	lsm_list_modules		sys_lsm_list_modules
-462	common	mseal				sys_mseal
-463	common	setxattrat			sys_setxattrat
-464	common	getxattrat			sys_getxattrat
-465	common	listxattrat			sys_listxattrat
-466	common	removexattrat			sys_removexattrat
-467	common	open_tree_attr			sys_open_tree_attr
-468	common	file_getattr			sys_file_getattr
-469	common	file_setattr			sys_file_setattr
-470	common	listns				sys_listns
-471	common	rseq_slice_yield		sys_rseq_slice_yield

-- 
2.55.0

Re: [PATCH RFC 1/4] syscalls: Create unified partial table for all archs

[Arnd Bergmann]

On Fri, Jul 24, 2026, at 22:00, André Almeida wrote:
> To take advantage of the subset of syscall numbers that are guaranteed to
> be shared, create a new table and adapt generation scripts to use it. In
> that way, every new syscall can be added to a single file.
>
> Signed-off-by: André Almeida <andrealmeid@igalia.com>

Thanks a lot for working on this, I had planned to do this myself
for a while but had never quite gotten around to finish it.

> +#
> +# syscall numbers shared by architectures
> +
> +442	common	mount_setattr			sys_mount_setattr
> +443	common	quotactl_fd			sys_quotactl_fd
> +444	common	landlock_create_ruleset		sys_landlock_create_ruleset
> +445	common	landlock_add_rule		sys_landlock_add_rule

It should really be anything starting at 403, not just 442 and higher.

There are some trivial differences that have crept in over time,
but we should be able to work around those.

> index 22e34cd46b9b..77934a2d0f51 100755
> --- a/scripts/syscallhdr.sh
> +++ b/scripts/syscallhdr.sh
> @@ -26,6 +26,7 @@ usage() {
>  	echo >&2 "  --emit-nr          Emit the macro of the number of 
> syscalls (__NR_syscalls)"
>  	echo >&2 "  --offset OFFSET    The offset of syscall numbers"
>  	echo >&2 "  --prefix PREFIX    The prefix to the macro like 
> __NR_<PREFIX><NAME>"
> +	echo >&2 "  --common-tbl       Use the common number table"
>  	exit 1

Ideally we shouldn't even need this bit either, though it may
help for the transition phase.

     Arnd

Re: [PATCH RFC 2/4] syscalls: Add support for x86_x32 for the common syscall table

[Arnd Bergmann]

On Fri, Jul 24, 2026, at 22:00, André Almeida wrote:
> x86_x32 has a peculiar ordering: first, goes the x86 syscalls. Then, the
> shared syscall numbers from the common table, and finally the x86_x32
> syscall numbers. Adapt syscallhdr.sh script to take this into account.
>
> Let's hope that x32 is deprecated before the syscall table reaches syscall
> 512, to avoid making the shared table more confusing.
>
> Signed-off-by: André Almeida <andrealmeid@igalia.com>

The suggestion at the moment is to remove x32 in linux-7.4, and
I don't think your patches will hit 7.3 at this point, so hopefully
we don't need this bit either.

As we discussed recently [1], we likely still need to stay away from
the x32 range to avoid having conflicting numbers on x86-64 between
future number assignments and old kernels (< linux-5.4) that fail
to return -ENOSYS for x32 special syscalls. The only way we could
arguably consider reusing them is if glibc increases the minimum
kernel version from 3.2 to 5.4 before we get to that number, but
that is still slightly fragile because glibc is not the only
runtime to consider here.

     Arnd

[1] https://lore.kernel.org/lkml/29bdbdc4-caef-4486-8816-84422c23bc20@app.fastmail.com/

Re: [PATCH RFC 1/4] syscalls: Create unified partial table for all archs

[André Almeida]

Em 24/07/2026 17:09, Arnd Bergmann escreveu:
> On Fri, Jul 24, 2026, at 22:00, André Almeida wrote:
>> To take advantage of the subset of syscall numbers that are guaranteed to
>> be shared, create a new table and adapt generation scripts to use it. In
>> that way, every new syscall can be added to a single file.
>>
>> Signed-off-by: André Almeida <andrealmeid@igalia.com>
> 
> Thanks a lot for working on this, I had planned to do this myself
> for a while but had never quite gotten around to finish it.
> 
>> +#
>> +# syscall numbers shared by architectures
>> +
>> +442	common	mount_setattr			sys_mount_setattr
>> +443	common	quotactl_fd			sys_quotactl_fd
>> +444	common	landlock_create_ruleset		sys_landlock_create_ruleset
>> +445	common	landlock_add_rule		sys_landlock_add_rule
> 
> It should really be anything starting at 403, not just 442 and higher.
> 
> There are some trivial differences that have crept in over time,
> but we should be able to work around those.
> 

The thing that prevent me starting before 442 was how to deal with 
compat. If I add to the table

441	common	epoll_pwait2		sys_epoll_pwait2		compat_sys_epoll_pwait2

It will wrongly add

__SYSCALL_WITH_COMPAT(441, sys_epoll_pwait2, compat_sys_epoll_pwait2)

to arch/x86/include/generated/asm/syscalls_64.h.

Maybe I could add a --ignore-compat to scripts/syscalltbl.sh, and add 
this flag for 64 builds. What do you think?

>> index 22e34cd46b9b..77934a2d0f51 100755
>> --- a/scripts/syscallhdr.sh
>> +++ b/scripts/syscallhdr.sh
>> @@ -26,6 +26,7 @@ usage() {
>>   	echo >&2 "  --emit-nr          Emit the macro of the number of
>> syscalls (__NR_syscalls)"
>>   	echo >&2 "  --offset OFFSET    The offset of syscall numbers"
>>   	echo >&2 "  --prefix PREFIX    The prefix to the macro like
>> __NR_<PREFIX><NAME>"
>> +	echo >&2 "  --common-tbl       Use the common number table"
>>   	exit 1
> 
> Ideally we shouldn't even need this bit either, though it may
> help for the transition phase.
> 
>       Arnd

Re: [PATCH RFC 1/4] syscalls: Create unified partial table for all archs

[Arnd Bergmann]

On Fri, Jul 24, 2026, at 22:18, André Almeida wrote:
> Em 24/07/2026 17:09, Arnd Bergmann escreveu:
>> On Fri, Jul 24, 2026, at 22:00, André Almeida wrote:
>> It should really be anything starting at 403, not just 442 and higher.
>> 
>> There are some trivial differences that have crept in over time,
>> but we should be able to work around those.
>> 
>
> The thing that prevent me starting before 442 was how to deal with 
> compat. If I add to the table
>
> 441	common	epoll_pwait2		sys_epoll_pwait2		compat_sys_epoll_pwait2
>
> It will wrongly add
>
> __SYSCALL_WITH_COMPAT(441, sys_epoll_pwait2, compat_sys_epoll_pwait2)
>
> to arch/x86/include/generated/asm/syscalls_64.h.
>
> Maybe I could add a --ignore-compat to scripts/syscalltbl.sh, and add 
> this flag for 64 builds. What do you think?

IIRC, we can just use compat_sys_epoll_pwait2 for both i386
and x32, because compat_sigset_t is compatible with sigset_t --
they are only really different on big-endian targets, which
count the bits in a u64 different from two u32.

This problem also goes away once x32 is gone.

      Arnd

Re: [PATCH RFC 1/4] syscalls: Create unified partial table for all archs

[H. Peter Anvin]

On July 24, 2026 1:25:05 PM PDT, Arnd Bergmann <arnd@arndb.de> wrote:
>On Fri, Jul 24, 2026, at 22:18, André Almeida wrote:
>> Em 24/07/2026 17:09, Arnd Bergmann escreveu:
>>> On Fri, Jul 24, 2026, at 22:00, André Almeida wrote:
>>> It should really be anything starting at 403, not just 442 and higher.
>>> 
>>> There are some trivial differences that have crept in over time,
>>> but we should be able to work around those.
>>> 
>>
>> The thing that prevent me starting before 442 was how to deal with 
>> compat. If I add to the table
>>
>> 441	common	epoll_pwait2		sys_epoll_pwait2		compat_sys_epoll_pwait2
>>
>> It will wrongly add
>>
>> __SYSCALL_WITH_COMPAT(441, sys_epoll_pwait2, compat_sys_epoll_pwait2)
>>
>> to arch/x86/include/generated/asm/syscalls_64.h.
>>
>> Maybe I could add a --ignore-compat to scripts/syscalltbl.sh, and add 
>> this flag for 64 builds. What do you think?
>
>IIRC, we can just use compat_sys_epoll_pwait2 for both i386
>and x32, because compat_sigset_t is compatible with sigset_t --
>they are only really different on big-endian targets, which
>count the bits in a u64 different from two u32.
>
>This problem also goes away once x32 is gone.
>
>      Arnd
>

No reason to introduce another entry point if there's no difference. 

x86, after all, is littleendian and alignment-tolerant.

Re: [PATCH RFC 1/4] syscalls: Create unified partial table for all archs

[Arnd Bergmann]

On Fri, Jul 24, 2026, at 23:22, H. Peter Anvin wrote:
> On July 24, 2026 1:25:05 PM PDT, Arnd Bergmann <arnd@arndb.de> wrote:

>>> It will wrongly add
>>>
>>> __SYSCALL_WITH_COMPAT(441, sys_epoll_pwait2, compat_sys_epoll_pwait2)
>>>
>>> to arch/x86/include/generated/asm/syscalls_64.h.
>>>
>>> Maybe I could add a --ignore-compat to scripts/syscalltbl.sh, and add 
>>> this flag for 64 builds. What do you think?
>>
>>IIRC, we can just use compat_sys_epoll_pwait2 for both i386
>>and x32, because compat_sigset_t is compatible with sigset_t --
>>they are only really different on big-endian targets, which
>>count the bits in a u64 different from two u32.
>>
>>This problem also goes away once x32 is gone.
>
> No reason to introduce another entry point if there's no difference. 
>
> x86, after all, is littleendian and alignment-tolerant.

What I meant was the reverse: if the common table has the
compat_sys_epoll_pwait2 entry for compat targets and x32 is
the only outlier, we don't need a special case for that
to force it to use the sys_epoll_pwait2 variant since they
are identical on x86.

Looking again at the x86 table, I see that x32 is not even
described as a compat target and just takes the second (native
64-bit) argument of __SYSCALL_WITH_COMPAT() instead of third
anyway, so there wouldn't even be a problem if native
and compat were different.

     Arnd