The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.
Split bits.h into linux and common headers to make the latter suitable
for inclusion in the vDSO library.
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20200320145351.32292-3-vincenzo.frascino@arm.com
BIT(), GENMASK(), etc. are useful to define register bits of hardware.
However, low-level code is often written in assembly, where they are
not available due to the hard-coded 1UL, 0UL.
In fact, in-kernel headers such as arch/arm64/include/asm/sysreg.h
use _BITUL() instead of BIT() so that the register bit macros are
available in assembly.
Using macros in include/uapi/linux/const.h have two reasons:
[1] For use in uapi headers
We should use underscore-prefixed variants for user-space.
[2] For use in assembly code
Since _BITUL() uses UL(1) instead of 1UL, it can be used as an
alternative of BIT().
For [2], it is pretty easy to change BIT() etc. for use in assembly.
This allows to replace _BUTUL() in kernel-space headers with BIT().
Link: http://lkml.kernel.org/r/20190609153941.17249-1-yamada.masahiro@socionext.com
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In preparation for implementing the asm-generic atomic bitops in terms
of atomic_long_*(), we need to prevent <asm/atomic.h> implementations from
pulling in <linux/bitops.h>. A common reason for this include is for the
BITS_PER_BYTE definition, so move this and some other BIT() and masking
macros into a new header file, <linux/bits.h>.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Cc: yamada.masahiro@socionext.com
Link: https://lore.kernel.org/lkml/1529412794-17720-4-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
