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SubjectRe: [PATCH] mips: remove reference to "newer Loongson-3"
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在 2021/8/29 20:49, Xi Ruoyao 写道:
> Newest Loongson-3 processors have moved to use LoongArch architecture.
> Sadly, the LL/SC issue is still existing on both latest Loongson-3
> processors using MIPS64 (Loongson-3A4000) and LoongArch
> (Loongson-3A5000).
LLSC is fixed on Loongson-3A4000 as per CPUCFG report.
>
> As it's very unlikely there will be new Loongson-3 processors using
> MIPS64, let's stop people from false hoping.
>
> Signed-off-by: Xi Ruoyao <xry111@mengyan1223.wang>
> Cc: Huacai Chen <chenhuacai@kernel.org>
> ---
>
> Huacai: how's the status of LL/SC issue on Loongson-2K? If
> the issue exists on it as well, we can just force
> CPU_LOONGSON3_WORKAROUNDS when CONFIG_CPU_LOONGSON64 and
> CONFIG_SMP are both selected.

Loongson-2K do need LLSC workaround, although the reason behind the
workaround seems different...

Thanks.

- Jiaxun

>
> arch/mips/Kconfig | 9 ++-------
> 1 file changed, 2 insertions(+), 7 deletions(-)
>
> diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
> index 6dfb27d531dd..ff5f344a371e 100644
> --- a/arch/mips/Kconfig
> +++ b/arch/mips/Kconfig
> @@ -1433,19 +1433,14 @@ config LOONGSON3_ENHANCEMENT
> new Loongson-3 machines only, please say 'Y' here.
>
> config CPU_LOONGSON3_WORKAROUNDS
> - bool "Old Loongson-3 LLSC Workarounds"
> + bool "Loongson-3 LLSC Workarounds"
> default y if SMP
> depends on CPU_LOONGSON64
> help
> Loongson-3 processors have the llsc issues which require workarounds.
> Without workarounds the system may hang unexpectedly.
>
> - Newer Loongson-3 will fix these issues and no workarounds are needed.
> - The workarounds have no significant side effect on them but may
> - decrease the performance of the system so this option should be
> - disabled unless the kernel is intended to be run on old systems.
> -
> - If unsure, please say Y.
> + Say Y, unless you know what you are doing.
>
> config CPU_LOONGSON3_CPUCFG_EMULATION
> bool "Emulate the CPUCFG instruction on older Loongson cores"

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