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From:   =?utf-8?B?QmrDtnJuIFTDtnBlbA==?= <bjorn@kernel.org>
To:     Sunil V L <sunilvl@ventanamicro.com>, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org,
        linux-acpi@vger.kernel.org, linux-crypto@vger.kernel.org,
        platform-driver-x86@vger.kernel.org, llvm@lists.linux.dev
Cc:     Jonathan Corbet <corbet@lwn.net>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>, Len Brown <lenb@kernel.org>,
        Daniel Lezcano <daniel.lezcano@linaro.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Weili Qian <qianweili@huawei.com>,
        Zhou Wang <wangzhou1@hisilicon.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        Marc Zyngier <maz@kernel.org>,
        Maximilian Luz <luzmaximilian@gmail.com>,
        Hans de Goede <hdegoede@redhat.com>,
        Mark Gross <markgross@kernel.org>,
        Nathan Chancellor <nathan@kernel.org>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Tom Rix <trix@redhat.com>,
        "Rafael J . Wysocki" <rafael@kernel.org>,
        "David S . Miller" <davem@davemloft.net>,
        Sunil V L <sunilvl@ventanamicro.com>,
        "Rafael J . Wysocki" <rafael.j.wysocki@intel.com>
Subject: Re: [PATCH V4 05/23] ACPI: OSL: Make should_use_kmap() 0 for RISC-V
In-Reply-To: <20230404182037.863533-6-sunilvl@ventanamicro.com>
References: <20230404182037.863533-1-sunilvl@ventanamicro.com>
 <20230404182037.863533-6-sunilvl@ventanamicro.com>
Date:   Wed, 26 Apr 2023 18:47:20 +0200
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Sunil V L <sunilvl@ventanamicro.com> writes:

> Without this, if the tables are larger than 4K,
> acpi_map() will fail.
>
> Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
> ---
>  drivers/acpi/osl.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/acpi/osl.c b/drivers/acpi/osl.c
> index 3269a888fb7a..f725813d0cce 100644
> --- a/drivers/acpi/osl.c
> +++ b/drivers/acpi/osl.c
> @@ -276,7 +276,7 @@ acpi_map_lookup_virt(void __iomem *virt, acpi_size si=
ze)
>  	return NULL;
>  }
>=20=20
> -#if defined(CONFIG_IA64) || defined(CONFIG_ARM64)
> +#if defined(CONFIG_IA64) || defined(CONFIG_ARM64) || defined(CONFIG_RISC=
V)
>  /* ioremap will take care of cache attributes */
>  #define should_use_kmap(pfn)   0

An observation, which can be addressed later; The acpi_os_ioremap()
(called when the config above is enabled for RV), does not have an arch
specific implementation for RISC-V. The generic one calls
ioremap_cached(), which on RISC-V defaults to ioremap() -- caching
disabled/_PAGE_IO.

That is probably not what we want, but rather something similar that
arm64 does.


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