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From: Christoph Hellwig <hch@infradead.org>
To: guoren@kernel.org
Cc: palmer@rivosinc.com, linux-riscv@lists.infradead.org,
	Guo Ren <guoren@linux.alibaba.com>
Subject: Re: [RFC PATCH 1/4] riscv: Optimize satp_mode data type
Date: Tue, 5 Jul 2022 10:26:11 -0700	[thread overview]
Message-ID: <YsR0M9ZyyUJxSpOk@infradead.org> (raw)
In-Reply-To: <20220705100523.1204595-2-guoren@kernel.org>

On Tue, Jul 05, 2022 at 06:05:20AM -0400, guoren@kernel.org wrote:
> From: Guo Ren <guoren@linux.alibaba.com>
> 
> Fixup satp_mode data type. Use ulong instead of u64 for rv32
> compatibility. Because the u64 type didn't cause any real problem, make
> it as optimized.

The changelog loooks odd, but given that CSR are Xlen sized this
is the right thing to do even without further justification.

> -extern u64 satp_mode;
> +extern ulong satp_mode;

.. but please spell out unsigned long.

>  #ifdef CONFIG_64BIT
> -u64 satp_mode __ro_after_init = !IS_ENABLED(CONFIG_XIP_KERNEL) ? SATP_MODE_57 : SATP_MODE_39;
> +ulong satp_mode __ro_after_init = !IS_ENABLED(CONFIG_XIP_KERNEL) ? SATP_MODE_57 : SATP_MODE_39;
>  #else
> -u64 satp_mode __ro_after_init = SATP_MODE_32;
> +ulong satp_mode __ro_after_init = SATP_MODE_32;
>  #endif

And maybe make this less of a mess while we're at it:

#ifdef CONFIG_32BIT
#define SATP_DEFAULT	SATP_MODE_32
#elif defined(CONFIG_XIP_KERNEL)
#define SATP_DEFAULT	SATP_MODE_39
#else
#define SATP_DEFAULT	SATP_MODE_57
#endif

unsigned long satp_mode __ro_after_init = SATP_DEFAULT;

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  reply	other threads:[~2022-07-05 17:26 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-05 10:05 [RFC PATCH 0/4] Proof of concept for rv32 svpbmt support guoren
2022-07-05 10:05 ` [RFC PATCH 1/4] riscv: Optimize satp_mode data type guoren
2022-07-05 17:26   ` Christoph Hellwig [this message]
2022-07-05 23:45     ` Guo Ren
2022-07-05 10:05 ` [RFC PATCH 2/4] riscv: Cleanup ERRATA_THEAD_PBMT for rv32 svpbmt compile guoren
2022-07-08  8:50   ` Heiko Stübner
2022-07-09 16:24     ` Guo Ren
2022-07-10  2:25     ` Guo Ren
2022-07-05 10:05 ` [RFC PATCH 3/4] riscv: pgtable: Move svpbmt into the common pgtable-bits.h guoren
2022-07-08  6:10   ` Guo Ren
2022-07-08  9:03     ` Heiko Stübner
2022-07-08  9:49       ` Guo Ren
2022-07-05 10:05 ` [RFC PATCH 4/4] riscv: Change rv32p34 to rv32p31 for svpbmt guoren
2022-07-05 17:22 ` [RFC PATCH 0/4] Proof of concept for rv32 svpbmt support Christoph Hellwig

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