While the GCC and Clang compilers already define __ASSEMBLER__
automatically when compiling assembler code, __ASSEMBLY__ is a
macro that only gets defined by the Makefiles in the kernel.
This is bad since macros starting with two underscores are names
that are reserved by the C language. It can also be very confusing
for the developers when switching between userspace and kernelspace
coding, or when dealing with uapi headers that rather should use
__ASSEMBLER__ instead. So let's standardize now on the __ASSEMBLER__
macro that is provided by the compilers.
This is almost a completely mechanical patch (done with a simple
"sed -i" statement), apart from tweaking two comments manually in
arch/powerpc/include/asm/bug.h and arch/powerpc/include/asm/kasan.h
(which did not have proper underscores at the end) and fixing a
checkpatch error about spaces in arch/powerpc/include/asm/spu_csa.h.
Signed-off-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Link: https://patch.msgid.link/20250801082007.32904-3-thuth@redhat.com
We want to move away from using SMT priority updates for cpu_relax, and
use a 'wait' instruction which is similar to x86. As well as being a
much better fit for what everybody else uses and tests with, priority
nops are stateful which is nasty (interrupts have to consider they might
be taken at a different priority), and they're expensive to execute,
similar to a mtSPR which can effect other threads in the pipe.
This has shown to give results that are less affected by code alignment
on benchmarks that cause a lot of spin waiting (e.g., rwsem contention
on unixbench filesystem benchmarks) on POWER10.
QEMU TCG only supports this instruction correctly since v7.1, versions
without the fix may cause hangs whne running POWER10 CPUs.
Reviewed-by: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Fix checkpatch warnings RE the macros]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220920122259.363092-2-npiggin@gmail.com
HMT_xxx macros are macros for adjusting thread priority
(hardware multi-threading) are macros inherited from PPC64
via commit 5f7c690728 ("[PATCH] powerpc: Merged ppc_asm.h")
Those instructions are pointless on PPC32, but some common
fonctions like arch_cpu_idle() use them.
So make them empty on PPC32 to avoid those instructions.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/c5a07fadea33d640ad10cecf0ac8faaec1c524e0.1629898474.git.christophe.leroy@csgroup.eu
cpu_relax() need to be in asm/vdso/processor.h to be used by
the C VDSO generic library.
Move it there.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201126131006.2431205-2-mpe@ellerman.id.au
Thomas Huth