[PATCH] arch: um/x86: Select ARCH_SUPPORTS_ATOMIC_RMW for UML_X86

Boqun Feng
2026-01-06T03:40:50Z

x86 atomic instructions are used for um on UML_X86, therefore atomics
on UML_X86 support native atomic RmW as x86 does, hence select
ARCH_SUPPORTS_ATOMIC_RMW.

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
---
UM & x86 maintainers,

I need this to avoid a build error for Rust atomics since Rust currently
only support Atomic<i8/i16> on ARCH_SUPPORTS_ATOMIC_RMW archs. I will
add it to my upcoming PR if I get some Acked-by, thanks!

arch/x86/um/Kconfig | 1 +
1 file changed, 1 insertion(+)

diff --git a/arch/x86/um/Kconfig b/arch/x86/um/Kconfig
index bdd7c8e39b01..44b12e45f9a0 100644
--- a/arch/x86/um/Kconfig
+++ b/arch/x86/um/Kconfig
@@ -9,6 +9,7 @@ endmenu
config UML_X86
def_bool y
select ARCH_USE_QUEUED_RWLOCKS
+ select ARCH_SUPPORTS_ATOMIC_RMW
select ARCH_USE_QUEUED_SPINLOCKS
select DCACHE_WORD_ACCESS
select HAVE_EFFICIENT_UNALIGNED_ACCESS
--
2.51.0