kernel/arch/arm/include/asm/unistd.h, branch linux-6.2.y

Merge tag 'clone3-v5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux

2019-07-11T17:09:44Z

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

arch: handle arches who do not yet define clone3

2019-06-20T23:54:53Z

This cleanly handles arches who do not yet define clone3. clone3() was initially placed under __ARCH_WANT_SYS_CLONE under the assumption that this would cleanly handle all architectures. It does not. Architectures such as nios2 or h8300 simply take the asm-generic syscall definitions and generate their syscall table from it. Since they don't define __ARCH_WANT_SYS_CLONE the build would fail complaining about sys_clone3 missing. The reason this doesn't happen for legacy clone is that nios2 and h8300 provide assembly stubs for sys_clone. This seems to be done for architectural reasons. The build failures for nios2 and h8300 were caught int -next luckily. The solution is to define __ARCH_WANT_SYS_CLONE3 that architectures can add. Additionally, we need a cond_syscall(clone3) for architectures such as nios2 or h8300 that generate their syscall table in the way I explained above. Fixes: 8f3220a80654 ("arch: wire-up clone3() syscall") Signed-off-by: Christian Brauner Cc: Arnd Bergmann Cc: Kees Cook Cc: David Howells Cc: Andrew Morton Cc: Oleg Nesterov Cc: Adrian Reber Cc: Linus Torvalds Cc: Al Viro Cc: Florian Weimer Cc: linux-api@vger.kernel.org Cc: linux-arch@vger.kernel.org Cc: x86@kernel.org

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

2019-06-19T15:09:55Z

Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Enrico Weigelt Reviewed-by: Kate Stewart Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman

y2038: rename old time and utime syscalls

2019-02-06T23:13:28Z

The time, stime, utime, utimes, and futimesat system calls are only used on older architectures, and we do not provide y2038 safe variants of them, as they are replaced by clock_gettime64, clock_settime64, and utimensat_time64. However, for consistency it seems better to have the 32-bit architectures that still use them call the "time32" entry points (leaving the traditional handlers for the 64-bit architectures), like we do for system calls that now require two versions. Note: We used to always define __ARCH_WANT_SYS_TIME and __ARCH_WANT_SYS_UTIME and only set __ARCH_WANT_COMPAT_SYS_TIME and __ARCH_WANT_SYS_UTIME32 for compat mode on 64-bit kernels. Now this is reversed: only 64-bit architectures set __ARCH_WANT_SYS_TIME/UTIME, while we need __ARCH_WANT_SYS_TIME32/UTIME32 for 32-bit architectures and compat mode. The resulting asm/unistd.h changes look a bit counterintuitive. This is only a cleanup patch and it should not change any behavior. Signed-off-by: Arnd Bergmann Acked-by: Geert Uytterhoeven Acked-by: Heiko Carstens

ARM: add migrate_pages() system call

2019-01-25T16:22:43Z

The migrate_pages system call has an assigned number on all architectures except ARM. When it got added initially in commit d80ade7b3231 ("ARM: Fix warning: #warning syscall migrate_pages not implemented"), it was intentionally left out based on the observation that there are no 32-bit ARM NUMA systems. However, there are now arm64 NUMA machines that can in theory run 32-bit kernels (actually enabling NUMA there would require additional work) as well as 32-bit user space on 64-bit kernels, so that argument is no longer very strong. Assigning the number lets us use the system call on 64-bit kernels as well as providing a more consistent set of syscalls across architectures. Signed-off-by: Arnd Bergmann Acked-by: Catalin Marinas

y2038: Compile utimes()/futimesat() conditionally

2018-08-29T13:42:23Z

There are four generations of utimes() syscalls: utime(), utimes(), futimesat() and utimensat(), each one being a superset of the previous one. For y2038 support, we have to add another one, which is the same as the existing utimensat() but always passes 64-bit times_t based timespec values. There are currently 10 architectures that only use utimensat(), two that use utimes(), futimesat() and utimensat() but not utime(), and 11 architectures that have all four, and those define __ARCH_WANT_SYS_UTIME in order to get a sys_utime implementation. Since all the new architectures only want utimensat(), moving all the legacy entry points into a common __ARCH_WANT_SYS_UTIME guard simplifies the logic. Only alpha and ia64 grow a tiny bit as they now also get an unused sys_utime(), but it didn't seem worth the extra complexity of adding yet another ifdef for those. Signed-off-by: Arnd Bergmann

asm-generic: Remove unneeded __ARCH_WANT_SYS_LLSEEK macro

2018-08-29T13:42:21Z

The sys_llseek sytem call is needed on all 32-bit architectures and none of the 64-bit ones, so we can remove the __ARCH_WANT_SYS_LLSEEK guard and simplify the include/asm-generic/unistd.h header further. Since 32-bit tasks can run either natively or in compat mode on 64-bit architectures, we have to check for both !CONFIG_64BIT and CONFIG_COMPAT. There are a few 64-bit architectures that also reference sys_llseek in their 64-bit ABI (e.g. sparc), but I verified that those all select CONFIG_COMPAT, so the #if check is still correct here. It's a bit odd to include it in the syscall table though, as it's the same as sys_lseek() on 64-bit, but with strange calling conventions. Acked-by: Geert Uytterhoeven Reviewed-by: Christoph Hellwig Signed-off-by: Arnd Bergmann

y2038: Remove newstat family from default syscall set

2018-08-29T13:42:20Z

We have four generations of stat() syscalls: - the oldstat syscalls that are only used on the older architectures - the newstat family that is used on all 64-bit architectures but lacked support for large files on 32-bit architectures. - the stat64 family that is used mostly on 32-bit architectures to replace newstat - statx() to replace all of the above, adding 64-bit timestamps among other things. We already compile stat64 only on those architectures that need it, but newstat is always built, including on those that don't reference it. This adds a new __ARCH_WANT_NEW_STAT symbol along the lines of __ARCH_WANT_OLD_STAT and __ARCH_WANT_STAT64 to control compilation of newstat. All architectures that need it use an explict define, the others now get a little bit smaller, and future architecture (including 64-bit targets) won't ever see it. Acked-by: Geert Uytterhoeven Signed-off-by: Arnd Bergmann

ARM: convert to generated system call tables

2016-10-18T20:34:06Z

Convert ARM to use a similar mechanism to x86 to generate the unistd.h system call numbers and the various kernel system call tables. This means that rather than having to edit three places (asm/unistd.h for the total number of system calls, uapi/asm/unistd.h for the system call numbers, and arch/arm/kernel/calls.S for the call table) we have only one place to edit, making the process much more simple. The scripts have knowledge of the table padding requirements, so there's no need to worry about __NR_syscalls not fitting within the immediate constant field of ALU instructions anymore. Signed-off-by: Russell King

ARM: wire up preadv2 and pwritev2 syscalls

2016-04-07T20:57:02Z

Wire up the preadv2 and pwritev2 syscalls for ARM. Signed-off-by: Russell King