[PATCH 07/17] clone3: drop __ARCH_WANT_SYS_CLONE3 macro

Arnd Bergmann arnd at kernel.org
Thu Jul 4 07:36:01 PDT 2024 

From: Arnd Bergmann <arnd at arndb.de>

When clone3() was introduced, it was not obvious how each architecture
deals with setting up the stack and keeping the register contents in
a fork()-like system call, so this was left for the architecture
maintainers to implement, with __ARCH_WANT_SYS_CLONE3 defined by those
that already implement it.

Five years later, we still have a few architectures left that are missing
clone3(), and the macro keeps getting in the way as it's fundamentally
different from all the other __ARCH_WANT_SYS_* macros that are meant
to provide backwards-compatibility with applications using older
syscalls that are no longer provided by default.

Address this by reversing the polarity of the macro, adding an
__ARCH_BROKEN_SYS_CLONE3 macro to all architectures that don't
already provide the syscall, and remove __ARCH_WANT_SYS_CLONE3
from all the other ones.

Signed-off-by: Arnd Bergmann <arnd at arndb.de>
---
 arch/arc/include/uapi/asm/unistd.h             | 1 -
 arch/arm/include/asm/unistd.h                  | 1 -
 arch/arm64/include/uapi/asm/unistd.h           | 1 -
 arch/csky/include/uapi/asm/unistd.h            | 1 -
 arch/hexagon/include/uapi/asm/unistd.h         | 2 ++
 arch/loongarch/include/uapi/asm/unistd.h       | 1 -
 arch/m68k/include/asm/unistd.h                 | 1 -
 arch/mips/include/asm/unistd.h                 | 1 -
 arch/nios2/include/uapi/asm/unistd.h           | 2 ++
 arch/openrisc/include/uapi/asm/unistd.h        | 1 -
 arch/parisc/include/asm/unistd.h               | 1 -
 arch/powerpc/include/asm/unistd.h              | 1 -
 arch/riscv/include/uapi/asm/unistd.h           | 1 -
 arch/s390/include/asm/unistd.h                 | 1 -
 arch/sh/include/asm/unistd.h                   | 2 ++
 arch/sparc/include/asm/unistd.h                | 2 ++
 arch/x86/include/asm/unistd.h                  | 1 -
 arch/xtensa/include/asm/unistd.h               | 1 -
 include/uapi/asm-generic/unistd.h              | 4 ----
 kernel/fork.c                                  | 8 +++++---
 kernel/sys_ni.c                                | 2 --
 tools/arch/arm64/include/uapi/asm/unistd.h     | 1 -
 tools/arch/loongarch/include/uapi/asm/unistd.h | 1 -
 tools/include/uapi/asm-generic/unistd.h        | 4 ----
 24 files changed, 13 insertions(+), 29 deletions(-)

diff --git a/arch/arc/include/uapi/asm/unistd.h b/arch/arc/include/uapi/asm/unistd.h
index fa2713ae6bea..5eafa1115162 100644
--- a/arch/arc/include/uapi/asm/unistd.h
+++ b/arch/arc/include/uapi/asm/unistd.h
@@ -21,7 +21,6 @@
 #define __ARCH_WANT_SET_GET_RLIMIT
 #define __ARCH_WANT_SYS_EXECVE
 #define __ARCH_WANT_SYS_CLONE
-#define __ARCH_WANT_SYS_CLONE3
 #define __ARCH_WANT_SYS_VFORK
 #define __ARCH_WANT_SYS_FORK
 #define __ARCH_WANT_TIME32_SYSCALLS
diff --git a/arch/arm/include/asm/unistd.h b/arch/arm/include/asm/unistd.h
index 3676e82cf95c..9fb00973c608 100644
--- a/arch/arm/include/asm/unistd.h
+++ b/arch/arm/include/asm/unistd.h
@@ -37,7 +37,6 @@
 #define __ARCH_WANT_SYS_FORK
 #define __ARCH_WANT_SYS_VFORK
 #define __ARCH_WANT_SYS_CLONE
-#define __ARCH_WANT_SYS_CLONE3
 
 /*
  * Unimplemented (or alternatively implemented) syscalls
diff --git a/arch/arm64/include/uapi/asm/unistd.h b/arch/arm64/include/uapi/asm/unistd.h
index ce2ee8f1e361..9306726337fe 100644
--- a/arch/arm64/include/uapi/asm/unistd.h
+++ b/arch/arm64/include/uapi/asm/unistd.h
@@ -19,7 +19,6 @@
 #define __ARCH_WANT_NEW_STAT
 #define __ARCH_WANT_SET_GET_RLIMIT
 #define __ARCH_WANT_TIME32_SYSCALLS
-#define __ARCH_WANT_SYS_CLONE3
 #define __ARCH_WANT_MEMFD_SECRET
 
 #include <asm-generic/unistd.h>
diff --git a/arch/csky/include/uapi/asm/unistd.h b/arch/csky/include/uapi/asm/unistd.h
index e0594b6370a6..d529d0432876 100644
--- a/arch/csky/include/uapi/asm/unistd.h
+++ b/arch/csky/include/uapi/asm/unistd.h
@@ -3,7 +3,6 @@
 #define __ARCH_WANT_STAT64
 #define __ARCH_WANT_NEW_STAT
 #define __ARCH_WANT_SYS_CLONE
-#define __ARCH_WANT_SYS_CLONE3
 #define __ARCH_WANT_SET_GET_RLIMIT
 #define __ARCH_WANT_TIME32_SYSCALLS
 #define __ARCH_WANT_SYNC_FILE_RANGE2
diff --git a/arch/hexagon/include/uapi/asm/unistd.h b/arch/hexagon/include/uapi/asm/unistd.h
index 21ae22306b5d..4bea7428e747 100644
--- a/arch/hexagon/include/uapi/asm/unistd.h
+++ b/arch/hexagon/include/uapi/asm/unistd.h
@@ -38,4 +38,6 @@
 #define __ARCH_WANT_TIME32_SYSCALLS
 #define __ARCH_WANT_SYNC_FILE_RANGE2
 
+#define __ARCH_BROKEN_SYS_CLONE3
+
 #include <asm-generic/unistd.h>
diff --git a/arch/loongarch/include/uapi/asm/unistd.h b/arch/loongarch/include/uapi/asm/unistd.h
index fcb668984f03..191614b9b207 100644
--- a/arch/loongarch/include/uapi/asm/unistd.h
+++ b/arch/loongarch/include/uapi/asm/unistd.h
@@ -1,5 +1,4 @@
 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
 #define __ARCH_WANT_SYS_CLONE
-#define __ARCH_WANT_SYS_CLONE3
 
 #include <asm-generic/unistd.h>
diff --git a/arch/m68k/include/asm/unistd.h b/arch/m68k/include/asm/unistd.h
index 4ae52414cd9d..2e0047cf86f8 100644
--- a/arch/m68k/include/asm/unistd.h
+++ b/arch/m68k/include/asm/unistd.h
@@ -30,6 +30,5 @@
 #define __ARCH_WANT_SYS_SIGPROCMASK
 #define __ARCH_WANT_SYS_FORK
 #define __ARCH_WANT_SYS_VFORK
-#define __ARCH_WANT_SYS_CLONE3
 
 #endif /* _ASM_M68K_UNISTD_H_ */
diff --git a/arch/mips/include/asm/unistd.h b/arch/mips/include/asm/unistd.h
index 25a5253db7f4..ba83d3fb0a84 100644
--- a/arch/mips/include/asm/unistd.h
+++ b/arch/mips/include/asm/unistd.h
@@ -58,7 +58,6 @@
 # endif
 #define __ARCH_WANT_SYS_FORK
 #define __ARCH_WANT_SYS_CLONE
-#define __ARCH_WANT_SYS_CLONE3
 
 /* whitelists for checksyscalls */
 #define __IGNORE_fadvise64_64
diff --git a/arch/nios2/include/uapi/asm/unistd.h b/arch/nios2/include/uapi/asm/unistd.h
index 0b4bb1d41b28..d2bc5ac975fb 100644
--- a/arch/nios2/include/uapi/asm/unistd.h
+++ b/arch/nios2/include/uapi/asm/unistd.h
@@ -23,6 +23,8 @@
 #define __ARCH_WANT_SET_GET_RLIMIT
 #define __ARCH_WANT_TIME32_SYSCALLS
 
+#define __ARCH_BROKEN_SYS_CLONE3
+
 /* Use the standard ABI for syscalls */
 #include <asm-generic/unistd.h>
 
diff --git a/arch/openrisc/include/uapi/asm/unistd.h b/arch/openrisc/include/uapi/asm/unistd.h
index fae34c60fa88..566f8c4f8047 100644
--- a/arch/openrisc/include/uapi/asm/unistd.h
+++ b/arch/openrisc/include/uapi/asm/unistd.h
@@ -24,7 +24,6 @@
 #define __ARCH_WANT_SET_GET_RLIMIT
 #define __ARCH_WANT_SYS_FORK
 #define __ARCH_WANT_SYS_CLONE
-#define __ARCH_WANT_SYS_CLONE3
 #define __ARCH_WANT_TIME32_SYSCALLS
 
 #include <asm-generic/unistd.h>
diff --git a/arch/parisc/include/asm/unistd.h b/arch/parisc/include/asm/unistd.h
index e38f9a90ac15..98851ff7699a 100644
--- a/arch/parisc/include/asm/unistd.h
+++ b/arch/parisc/include/asm/unistd.h
@@ -160,7 +160,6 @@ type name(type1 arg1, type2 arg2, type3 arg3, type4 arg4, type5 arg5)	\
 #define __ARCH_WANT_SYS_FORK
 #define __ARCH_WANT_SYS_VFORK
 #define __ARCH_WANT_SYS_CLONE
-#define __ARCH_WANT_SYS_CLONE3
 #define __ARCH_WANT_COMPAT_SYS_SENDFILE
 #define __ARCH_WANT_COMPAT_STAT
 
diff --git a/arch/powerpc/include/asm/unistd.h b/arch/powerpc/include/asm/unistd.h
index 659a996c75aa..027ef94a12fb 100644
--- a/arch/powerpc/include/asm/unistd.h
+++ b/arch/powerpc/include/asm/unistd.h
@@ -51,7 +51,6 @@
 #define __ARCH_WANT_SYS_FORK
 #define __ARCH_WANT_SYS_VFORK
 #define __ARCH_WANT_SYS_CLONE
-#define __ARCH_WANT_SYS_CLONE3
 
 #endif		/* __ASSEMBLY__ */
 #endif /* _ASM_POWERPC_UNISTD_H_ */
diff --git a/arch/riscv/include/uapi/asm/unistd.h b/arch/riscv/include/uapi/asm/unistd.h
index 950ab3fd4409..328520defc13 100644
--- a/arch/riscv/include/uapi/asm/unistd.h
+++ b/arch/riscv/include/uapi/asm/unistd.h
@@ -20,7 +20,6 @@
 #define __ARCH_WANT_SET_GET_RLIMIT
 #endif /* __LP64__ */
 
-#define __ARCH_WANT_SYS_CLONE3
 #define __ARCH_WANT_MEMFD_SECRET
 
 #include <asm-generic/unistd.h>
diff --git a/arch/s390/include/asm/unistd.h b/arch/s390/include/asm/unistd.h
index 4260bc5ce7f8..70fc671397da 100644
--- a/arch/s390/include/asm/unistd.h
+++ b/arch/s390/include/asm/unistd.h
@@ -35,6 +35,5 @@
 #define __ARCH_WANT_SYS_FORK
 #define __ARCH_WANT_SYS_VFORK
 #define __ARCH_WANT_SYS_CLONE
-#define __ARCH_WANT_SYS_CLONE3
 
 #endif /* _ASM_S390_UNISTD_H_ */
diff --git a/arch/sh/include/asm/unistd.h b/arch/sh/include/asm/unistd.h
index d6e126250136..3d7f35650a13 100644
--- a/arch/sh/include/asm/unistd.h
+++ b/arch/sh/include/asm/unistd.h
@@ -28,4 +28,6 @@
 # define __ARCH_WANT_SYS_VFORK
 # define __ARCH_WANT_SYS_CLONE
 
+#define __ARCH_BROKEN_SYS_CLONE3
+
 #include <uapi/asm/unistd.h>
diff --git a/arch/sparc/include/asm/unistd.h b/arch/sparc/include/asm/unistd.h
index d6bc76706a7a..3380411a4537 100644
--- a/arch/sparc/include/asm/unistd.h
+++ b/arch/sparc/include/asm/unistd.h
@@ -49,6 +49,8 @@
 #define __ARCH_WANT_COMPAT_STAT
 #endif
 
+#define __ARCH_BROKEN_SYS_CLONE3
+
 #ifdef __32bit_syscall_numbers__
 /* Sparc 32-bit only has the "setresuid32", "getresuid32" variants,
  * it never had the plain ones and there is no value to adding those
diff --git a/arch/x86/include/asm/unistd.h b/arch/x86/include/asm/unistd.h
index 761173ccc33c..6c9e5bdd3916 100644
--- a/arch/x86/include/asm/unistd.h
+++ b/arch/x86/include/asm/unistd.h
@@ -56,6 +56,5 @@
 # define __ARCH_WANT_SYS_FORK
 # define __ARCH_WANT_SYS_VFORK
 # define __ARCH_WANT_SYS_CLONE
-# define __ARCH_WANT_SYS_CLONE3
 
 #endif /* _ASM_X86_UNISTD_H */
diff --git a/arch/xtensa/include/asm/unistd.h b/arch/xtensa/include/asm/unistd.h
index b52236245e51..30af4dc3ce7b 100644
--- a/arch/xtensa/include/asm/unistd.h
+++ b/arch/xtensa/include/asm/unistd.h
@@ -3,7 +3,6 @@
 #define _XTENSA_UNISTD_H
 
 #define __ARCH_WANT_SYS_CLONE
-#define __ARCH_WANT_SYS_CLONE3
 #include <uapi/asm/unistd.h>
 
 #define __ARCH_WANT_NEW_STAT
diff --git a/include/uapi/asm-generic/unistd.h b/include/uapi/asm-generic/unistd.h
index d4cc26932ff4..5bf6148cac2b 100644
--- a/include/uapi/asm-generic/unistd.h
+++ b/include/uapi/asm-generic/unistd.h
@@ -776,12 +776,8 @@ __SYSCALL(__NR_fsmount, sys_fsmount)
 __SYSCALL(__NR_fspick, sys_fspick)
 #define __NR_pidfd_open 434
 __SYSCALL(__NR_pidfd_open, sys_pidfd_open)
-
-#ifdef __ARCH_WANT_SYS_CLONE3
 #define __NR_clone3 435
 __SYSCALL(__NR_clone3, sys_clone3)
-#endif
-
 #define __NR_close_range 436
 __SYSCALL(__NR_close_range, sys_close_range)
 #define __NR_openat2 437
diff --git a/kernel/fork.c b/kernel/fork.c
index 99076dbe27d8..02f322424c49 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -2941,8 +2941,6 @@ SYSCALL_DEFINE5(clone, unsigned long, clone_flags, unsigned long, newsp,
 }
 #endif
 
-#ifdef __ARCH_WANT_SYS_CLONE3
-
 noinline static int copy_clone_args_from_user(struct kernel_clone_args *kargs,
 					      struct clone_args __user *uargs,
 					      size_t usize)
@@ -3086,6 +3084,11 @@ SYSCALL_DEFINE2(clone3, struct clone_args __user *, uargs, size_t, size)
 	struct kernel_clone_args kargs;
 	pid_t set_tid[MAX_PID_NS_LEVEL];
 
+#ifdef __ARCH_BROKEN_SYS_CLONE3
+#warning clone3() entry point is missing, please fix
+	return -ENOSYS;
+#endif
+
 	kargs.set_tid = set_tid;
 
 	err = copy_clone_args_from_user(&kargs, uargs, size);
@@ -3097,7 +3100,6 @@ SYSCALL_DEFINE2(clone3, struct clone_args __user *, uargs, size_t, size)
 
 	return kernel_clone(&kargs);
 }
-#endif
 
 void walk_process_tree(struct task_struct *top, proc_visitor visitor, void *data)
 {
diff --git a/kernel/sys_ni.c b/kernel/sys_ni.c
index b696b85ac63e..2ef820a2d067 100644
--- a/kernel/sys_ni.c
+++ b/kernel/sys_ni.c
@@ -76,8 +76,6 @@ COND_SYSCALL(timerfd_gettime32);
 COND_SYSCALL(acct);
 COND_SYSCALL(capget);
 COND_SYSCALL(capset);
-/* __ARCH_WANT_SYS_CLONE3 */
-COND_SYSCALL(clone3);
 COND_SYSCALL(futex);
 COND_SYSCALL(futex_time32);
 COND_SYSCALL(set_robust_list);
diff --git a/tools/arch/arm64/include/uapi/asm/unistd.h b/tools/arch/arm64/include/uapi/asm/unistd.h
index ce2ee8f1e361..9306726337fe 100644
--- a/tools/arch/arm64/include/uapi/asm/unistd.h
+++ b/tools/arch/arm64/include/uapi/asm/unistd.h
@@ -19,7 +19,6 @@
 #define __ARCH_WANT_NEW_STAT
 #define __ARCH_WANT_SET_GET_RLIMIT
 #define __ARCH_WANT_TIME32_SYSCALLS
-#define __ARCH_WANT_SYS_CLONE3
 #define __ARCH_WANT_MEMFD_SECRET
 
 #include <asm-generic/unistd.h>
diff --git a/tools/arch/loongarch/include/uapi/asm/unistd.h b/tools/arch/loongarch/include/uapi/asm/unistd.h
index 0c743344e92d..8eeaac0087c3 100644
--- a/tools/arch/loongarch/include/uapi/asm/unistd.h
+++ b/tools/arch/loongarch/include/uapi/asm/unistd.h
@@ -4,6 +4,5 @@
  */
 
 #define __ARCH_WANT_SYS_CLONE
-#define __ARCH_WANT_SYS_CLONE3
 
 #include <asm-generic/unistd.h>
diff --git a/tools/include/uapi/asm-generic/unistd.h b/tools/include/uapi/asm-generic/unistd.h
index d983c48a3b6a..a00d53d02723 100644
--- a/tools/include/uapi/asm-generic/unistd.h
+++ b/tools/include/uapi/asm-generic/unistd.h
@@ -776,12 +776,8 @@ __SYSCALL(__NR_fsmount, sys_fsmount)
 __SYSCALL(__NR_fspick, sys_fspick)
 #define __NR_pidfd_open 434
 __SYSCALL(__NR_pidfd_open, sys_pidfd_open)
-
-#ifdef __ARCH_WANT_SYS_CLONE3
 #define __NR_clone3 435
 __SYSCALL(__NR_clone3, sys_clone3)
-#endif
-
 #define __NR_close_range 436
 __SYSCALL(__NR_close_range, sys_close_range)
 #define __NR_openat2 437
-- 
2.39.2

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