asm-generic: Make time32 syscall numbers optional

We don't want new architectures to even provide the old 32-bit time_t
based system calls any more, or define the syscall number macros.

Add a new __ARCH_WANT_TIME32_SYSCALLS macro that gets enabled for all
existing 32-bit architectures using the generic system call table,
so we don't change any current behavior.
Since this symbol is evaluated in user space as well, we cannot use
a Kconfig CONFIG_* macro but have to define it in uapi/asm/unistd.h.

On 64-bit architectures, the same system call numbers mostly refer to
the system calls we want to keep, as they already pass 64-bit time_t.

As new architectures no longer provide these, we need new exceptions
in checksyscalls.sh.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

asm-generic: Drop getrlimit and setrlimit syscalls from default list

The newer prlimit64 syscall provides all the functionality of getrlimit
and setrlimit syscalls and adds the pid of target process, so future
architectures won't need to include getrlimit and setrlimit.

Therefore drop getrlimit and setrlimit syscalls from the generic syscall
list unless __ARCH_WANT_SET_GET_RLIMIT is defined by the architecture's
unistd.h prior to including asm-generic/unistd.h, and adjust all
architectures using the generic syscall list to define it so that no
in-tree architectures are affected.

Cc: Arnd Bergmann <arnd@arndb.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-hexagon@vger.kernel.org
Cc: uclinux-h8-devel@lists.sourceforge.jp
Signed-off-by: Yury Norov <ynorov@caviumnetworks.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Mark Salter <msalter@redhat.com> [c6x]
Acked-by: James Hogan <james.hogan@imgtec.com> [metag]
Acked-by: Ley Foon Tan <lftan@altera.com> [nios2]
Acked-by: Stafford Horne <shorne@gmail.com> [openrisc]
Acked-by: Will Deacon <will.deacon@arm.com> [arm64]
Acked-by: Vineet Gupta <vgupta@synopsys.com> #arch/arc bits
Signed-off-by: Yury Norov <ynorov@marvell.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

y2038: Remove stat64 family from default syscall set

New architectures should no longer need stat64, which is not y2038
safe and has been replaced by statx(). This removes the 'select
__ARCH_WANT_STAT64' statement from asm-generic/unistd.h and instead
moves it into the respective asm/unistd.h UAPI header files for each
architecture that uses it today.

In the generic file, the system call number and entry points are now
made conditional, so newly added architectures (e.g. riscv32 or csky)
will never need to carry backwards compatiblity for it.

arm64 is the only 64-bit architecture using the asm-generic/unistd.h
file, and it already sets __ARCH_WANT_NEW_STAT in its headers, and I
use the same #ifdef here: future 64-bit architectures therefore won't
see newstat or stat64 any more. They don't suffer from the y2038 time_t
overflow, but for consistency it seems best to also let them use statx().

Signed-off-by: Arnd Bergmann <arnd@arndb.de>

License cleanup: add SPDX license identifier to uapi header files with a license

Many user space API headers have licensing information, which is either
incomplete, badly formatted or just a shorthand for referring to the
license under which the file is supposed to be. This makes it hard for
compliance tools to determine the correct license.

Update these files with an SPDX license identifier. The identifier was
chosen based on the license information in the file.

GPL/LGPL licensed headers get the matching GPL/LGPL SPDX license
identifier with the added 'WITH Linux-syscall-note' exception, which is
the officially assigned exception identifier for the kernel syscall
exception:

NOTE! This copyright does *not* cover user programs that use kernel
services by normal system calls - this is merely considered normal use
of the kernel, and does *not* fall under the heading of "derived work".

This exception makes it possible to include GPL headers into non GPL
code, without confusing license compliance tools.

Headers which have either explicit dual licensing or are just licensed
under a non GPL license are updated with the corresponding SPDX
identifier and the GPLv2 with syscall exception identifier. The format
is:
((GPL-2.0 WITH Linux-syscall-note) OR SPDX-ID-OF-OTHER-LICENSE)

SPDX license identifiers are a legally binding shorthand, which can be
used instead of the full boiler plate text. The update does not remove
existing license information as this has to be done on a case by case
basis and the copyright holders might have to be consulted. This will
happen in a separate step.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne. See the previous patch in this series for the
methodology of how this patch was researched.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

asm-generic: Drop renameat syscall from default list

The newer renameat2 syscall provides all the functionality provided by
the renameat syscall and adds flags, so future architectures won't need
to include renameat.

Therefore drop the renameat syscall from the generic syscall list unless
__ARCH_WANT_RENAMEAT is defined by the architecture's unistd.h prior to
including asm-generic/unistd.h, and adjust all architectures using the
generic syscall list to define it so that no in-tree architectures are
affected.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Cc: linux-arch@vger.kernel.org
Cc: linux-snps-arc@lists.infradead.org
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: Mark Salter <msalter@redhat.com>
Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
Cc: linux-c6x-dev@linux-c6x.org
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: linux-hexagon@vger.kernel.org
Cc: linux-metag@vger.kernel.org
Cc: Jonas Bonn <jonas@southpole.se>
Cc: linux@lists.openrisc.net
Cc: Chen Liqin <liqin.linux@gmail.com>
Cc: Lennox Wu <lennox.wu@gmail.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: nios2-dev@lists.rocketboards.org
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: uclinux-h8-devel@lists.sourceforge.jp
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

nios2: System calls handling

This patch adds support for system calls from userspaces. It uses the
asm-generic/unistd.h definitions with architecture spcific syscall.
The sys_call_table is just an array defined in a C file and it contains
pointers to the syscall functions.

Signed-off-by: Ley Foon Tan <lftan@altera.com>