2020-06-02 00:58:51

by Chenxi Mao

Subject: [PATCH 1/1] riscv: Select ARCH_SUPPORTS_ATOMIC_RMW by default

Enable ARCH_SUPPORTS_ATOMIC_RMW by default to support
osq_lock in mutex/rwsem locks.
---
arch/riscv/Kconfig | 1 +
1 file changed, 1 insertion(+)

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index a31e1a41913a..cbdc605d20d9 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -68,6 +68,7 @@ config RISCV
select ARCH_HAS_GCOV_PROFILE_ALL
select HAVE_COPY_THREAD_TLS
select HAVE_ARCH_KASAN if MMU && 64BIT
+ select ARCH_SUPPORTS_ATOMIC_RMW

config ARCH_MMAP_RND_BITS_MIN
default 18 if 64BIT
--
2.25.1

2020-06-05 00:07:15

by Palmer Dabbelt

Subject: Re: [PATCH 1/1] riscv: Select ARCH_SUPPORTS_ATOMIC_RMW by default

On Mon, 01 Jun 2020 17:54:28 PDT (-0700), [email protected] wrote:
> Enable ARCH_SUPPORTS_ATOMIC_RMW by default to support
> osq_lock in mutex/rwsem locks.
> ---
> arch/riscv/Kconfig | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index a31e1a41913a..cbdc605d20d9 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -68,6 +68,7 @@ config RISCV
> select ARCH_HAS_GCOV_PROFILE_ALL
> select HAVE_COPY_THREAD_TLS
> select HAVE_ARCH_KASAN if MMU && 64BIT
> + select ARCH_SUPPORTS_ATOMIC_RMW
>
> config ARCH_MMAP_RND_BITS_MIN
> default 18 if 64BIT

You need a Signed-off-by for all patches, even small ones like this. I'm also
going to consider this a bit too large of a change to take during the merge
window: there's very little code, but it dramatically changes the behavior of
the system -- in other words, it's a 5.9 candidate, not a 5.8 one.

Thanks!