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authorLinus Torvalds <torvalds@linux-foundation.org>2019-07-11 10:09:44 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-07-11 10:09:44 -0700
commit8f6ccf6159aed1f04c6d179f61f6fb2691261e84 (patch)
tree449c6d9cddc6f94c6450a18885b6a06e8a67d845 /arch
parent5450e8a316a64cddcbc15f90733ebc78aa736545 (diff)
parentd68dbb0c9ac8b1ff52eb09aa58ce6358400fa939 (diff)
Merge tag 'clone3-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux
Pull clone3 system call from Christian Brauner: "This adds the clone3 syscall which is an extensible successor to clone after we snagged the last flag with CLONE_PIDFD during the 5.2 merge window for clone(). It cleanly supports all of the flags from clone() and thus all legacy workloads. There are few user visible differences between clone3 and clone. First, CLONE_DETACHED will cause EINVAL with clone3 so we can reuse this flag. Second, the CSIGNAL flag is deprecated and will cause EINVAL to be reported. It is superseeded by a dedicated "exit_signal" argument in struct clone_args thus freeing up even more flags. And third, clone3 gives CLONE_PIDFD a dedicated return argument in struct clone_args instead of abusing CLONE_PARENT_SETTID's parent_tidptr argument. The clone3 uapi is designed to be easy to handle on 32- and 64 bit: /* uapi */ struct clone_args { __aligned_u64 flags; __aligned_u64 pidfd; __aligned_u64 child_tid; __aligned_u64 parent_tid; __aligned_u64 exit_signal; __aligned_u64 stack; __aligned_u64 stack_size; __aligned_u64 tls; }; and a separate kernel struct is used that uses proper kernel typing: /* kernel internal */ struct kernel_clone_args { u64 flags; int __user *pidfd; int __user *child_tid; int __user *parent_tid; int exit_signal; unsigned long stack; unsigned long stack_size; unsigned long tls; }; The system call comes with a size argument which enables the kernel to detect what version of clone_args userspace is passing in. clone3 validates that any additional bytes a given kernel does not know about are set to zero and that the size never exceeds a page. A nice feature is that this patchset allowed us to cleanup and simplify various core kernel codepaths in kernel/fork.c by making the internal _do_fork() function take struct kernel_clone_args even for legacy clone(). This patch also unblocks the time namespace patchset which wants to introduce a new CLONE_TIMENS flag. Note, that clone3 has only been wired up for x86{_32,64}, arm{64}, and xtensa. These were the architectures that did not require special massaging. Other architectures treat fork-like system calls individually and after some back and forth neither Arnd nor I felt confident that we dared to add clone3 unconditionally to all architectures. We agreed to leave this up to individual architecture maintainers. This is why there's an additional patch that introduces __ARCH_WANT_SYS_CLONE3 which any architecture can set once it has implemented support for clone3. The patch also adds a cond_syscall(clone3) for architectures such as nios2 or h8300 that generate their syscall table by simply including asm-generic/unistd.h. The hope is to get rid of __ARCH_WANT_SYS_CLONE3 and cond_syscall() rather soon" * tag 'clone3-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux: arch: handle arches who do not yet define clone3 arch: wire-up clone3() syscall fork: add clone3
Diffstat (limited to 'arch')
-rw-r--r--arch/arm/include/asm/unistd.h1
-rw-r--r--arch/arm/tools/syscall.tbl1
-rw-r--r--arch/arm64/include/asm/unistd.h3
-rw-r--r--arch/arm64/include/asm/unistd32.h2
-rw-r--r--arch/microblaze/kernel/syscalls/syscall.tbl1
-rw-r--r--arch/x86/entry/syscalls/syscall_32.tbl1
-rw-r--r--arch/x86/entry/syscalls/syscall_64.tbl1
-rw-r--r--arch/x86/ia32/sys_ia32.c12
-rw-r--r--arch/x86/include/asm/unistd.h1
-rw-r--r--arch/xtensa/include/asm/unistd.h1
-rw-r--r--arch/xtensa/kernel/syscalls/syscall.tbl1
11 files changed, 22 insertions, 3 deletions
diff --git a/arch/arm/include/asm/unistd.h b/arch/arm/include/asm/unistd.h
index 9fb00973c608..3676e82cf95c 100644
--- a/arch/arm/include/asm/unistd.h
+++ b/arch/arm/include/asm/unistd.h
@@ -37,6 +37,7 @@
#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/arm/tools/syscall.tbl b/arch/arm/tools/syscall.tbl
index 81e6e1817c45..6da7dc4d79cc 100644
--- a/arch/arm/tools/syscall.tbl
+++ b/arch/arm/tools/syscall.tbl
@@ -448,3 +448,4 @@
432 common fsmount sys_fsmount
433 common fspick sys_fspick
434 common pidfd_open sys_pidfd_open
+435 common clone3 sys_clone3
diff --git a/arch/arm64/include/asm/unistd.h b/arch/arm64/include/asm/unistd.h
index ede7b88d4f15..2629a68b8724 100644
--- a/arch/arm64/include/asm/unistd.h
+++ b/arch/arm64/include/asm/unistd.h
@@ -38,10 +38,11 @@
#define __ARM_NR_compat_set_tls (__ARM_NR_COMPAT_BASE + 5)
#define __ARM_NR_COMPAT_END (__ARM_NR_COMPAT_BASE + 0x800)
-#define __NR_compat_syscalls 435
+#define __NR_compat_syscalls 436
#endif
#define __ARCH_WANT_SYS_CLONE
+#define __ARCH_WANT_SYS_CLONE3
#ifndef __COMPAT_SYSCALL_NR
#include <uapi/asm/unistd.h>
diff --git a/arch/arm64/include/asm/unistd32.h b/arch/arm64/include/asm/unistd32.h
index 52415923e08f..94ab29cf4f00 100644
--- a/arch/arm64/include/asm/unistd32.h
+++ b/arch/arm64/include/asm/unistd32.h
@@ -877,6 +877,8 @@ __SYSCALL(__NR_fsmount, sys_fsmount)
__SYSCALL(__NR_fspick, sys_fspick)
#define __NR_pidfd_open 434
__SYSCALL(__NR_pidfd_open, sys_pidfd_open)
+#define __NR_clone3 435
+__SYSCALL(__NR_clone3, sys_clone3)
/*
* Please add new compat syscalls above this comment and update
diff --git a/arch/microblaze/kernel/syscalls/syscall.tbl b/arch/microblaze/kernel/syscalls/syscall.tbl
index ad706f83c755..09b0cd7dab0a 100644
--- a/arch/microblaze/kernel/syscalls/syscall.tbl
+++ b/arch/microblaze/kernel/syscalls/syscall.tbl
@@ -440,3 +440,4 @@
432 common fsmount sys_fsmount
433 common fspick sys_fspick
434 common pidfd_open sys_pidfd_open
+435 common clone3 sys_clone3
diff --git a/arch/x86/entry/syscalls/syscall_32.tbl b/arch/x86/entry/syscalls/syscall_32.tbl
index 43e4429a5272..c00019abd076 100644
--- a/arch/x86/entry/syscalls/syscall_32.tbl
+++ b/arch/x86/entry/syscalls/syscall_32.tbl
@@ -439,3 +439,4 @@
432 i386 fsmount sys_fsmount __ia32_sys_fsmount
433 i386 fspick sys_fspick __ia32_sys_fspick
434 i386 pidfd_open sys_pidfd_open __ia32_sys_pidfd_open
+435 i386 clone3 sys_clone3 __ia32_sys_clone3
diff --git a/arch/x86/entry/syscalls/syscall_64.tbl b/arch/x86/entry/syscalls/syscall_64.tbl
index 1bee0a77fdd3..c29976eca4a8 100644
--- a/arch/x86/entry/syscalls/syscall_64.tbl
+++ b/arch/x86/entry/syscalls/syscall_64.tbl
@@ -356,6 +356,7 @@
432 common fsmount __x64_sys_fsmount
433 common fspick __x64_sys_fspick
434 common pidfd_open __x64_sys_pidfd_open
+435 common clone3 __x64_sys_clone3/ptregs
#
# x32-specific system call numbers start at 512 to avoid cache impact
diff --git a/arch/x86/ia32/sys_ia32.c b/arch/x86/ia32/sys_ia32.c
index a43212036257..64a6c952091e 100644
--- a/arch/x86/ia32/sys_ia32.c
+++ b/arch/x86/ia32/sys_ia32.c
@@ -237,6 +237,14 @@ COMPAT_SYSCALL_DEFINE5(x86_clone, unsigned long, clone_flags,
unsigned long, newsp, int __user *, parent_tidptr,
unsigned long, tls_val, int __user *, child_tidptr)
{
- return _do_fork(clone_flags, newsp, 0, parent_tidptr, child_tidptr,
- tls_val);
+ struct kernel_clone_args args = {
+ .flags = (clone_flags & ~CSIGNAL),
+ .child_tid = child_tidptr,
+ .parent_tid = parent_tidptr,
+ .exit_signal = (clone_flags & CSIGNAL),
+ .stack = newsp,
+ .tls = tls_val,
+ };
+
+ return _do_fork(&args);
}
diff --git a/arch/x86/include/asm/unistd.h b/arch/x86/include/asm/unistd.h
index 146859efd83c..097589753fec 100644
--- a/arch/x86/include/asm/unistd.h
+++ b/arch/x86/include/asm/unistd.h
@@ -54,5 +54,6 @@
# 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 30af4dc3ce7b..b52236245e51 100644
--- a/arch/xtensa/include/asm/unistd.h
+++ b/arch/xtensa/include/asm/unistd.h
@@ -3,6 +3,7 @@
#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/arch/xtensa/kernel/syscalls/syscall.tbl b/arch/xtensa/kernel/syscalls/syscall.tbl
index 782b81945ccc..25f4de729a6d 100644
--- a/arch/xtensa/kernel/syscalls/syscall.tbl
+++ b/arch/xtensa/kernel/syscalls/syscall.tbl
@@ -405,3 +405,4 @@
432 common fsmount sys_fsmount
433 common fspick sys_fspick
434 common pidfd_open sys_pidfd_open
+435 common clone3 sys_clone3