Re: [PATCH v8 1/2] riscv: Introduce set_kernel_memory helper

From: Atish Patra <atishp@atishpatra.org>
To: Alexandre Ghiti <alex@ghiti.fr>
Cc: Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Jisheng Zhang <jszhang@kernel.org>,
	Christoph Hellwig <hch@infradead.org>,
	Zong Li <zong.li@sifive.com>, Anup Patel <anup@brainfault.org>,
	linux-riscv <linux-riscv@lists.infradead.org>,
	"linux-kernel@vger.kernel.org List"
	<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v8 1/2] riscv: Introduce set_kernel_memory helper
Date: Thu, 24 Jun 2021 18:13:27 -0700	[thread overview]
Message-ID: <CAOnJCUKs-75Vd_Wmp_X5Wdf-5UPfXD3GzFnuDb8FjtT2WcFybg@mail.gmail.com> (raw)
In-Reply-To: <20210624120041.2786419-2-alex@ghiti.fr>

On Thu, Jun 24, 2021 at 5:02 AM Alexandre Ghiti <alex@ghiti.fr> wrote:
>
> This helper should be used for setting permissions to the kernel
> mapping as it takes pointers as arguments and then avoids explicit cast
> to unsigned long needed for the set_memory_* API.
>
> Suggested-by: Christoph Hellwig <hch@infradead.org>
> Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
> Reviewed-by: Anup Patel <anup@brainfault.org>
> ---
>  arch/riscv/include/asm/set_memory.h | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
>
> diff --git a/arch/riscv/include/asm/set_memory.h b/arch/riscv/include/asm/set_memory.h
> index 9d4d455726d4..96e317dcab13 100644
> --- a/arch/riscv/include/asm/set_memory.h
> +++ b/arch/riscv/include/asm/set_memory.h
> @@ -17,6 +17,16 @@ int set_memory_x(unsigned long addr, int numpages);
>  int set_memory_nx(unsigned long addr, int numpages);
>  int set_memory_rw_nx(unsigned long addr, int numpages);
>  void protect_kernel_text_data(void);
> +static __always_inline int set_kernel_memory(char *startp, char *endp,
> +                                            int (*set_memory)(unsigned long start,
> +                                                              int num_pages))
> +{
> +       unsigned long start = (unsigned long)startp;
> +       unsigned long end = (unsigned long)endp;
> +       int num_pages = PAGE_ALIGN(end - start) >> PAGE_SHIFT;
> +
> +       return set_memory(start, num_pages);
> +}
>  #else
>  static inline int set_memory_ro(unsigned long addr, int numpages) { return 0; }
>  static inline int set_memory_rw(unsigned long addr, int numpages) { return 0; }
> @@ -24,6 +34,12 @@ static inline int set_memory_x(unsigned long addr, int numpages) { return 0; }
>  static inline int set_memory_nx(unsigned long addr, int numpages) { return 0; }
>  static inline void protect_kernel_text_data(void) {}
>  static inline int set_memory_rw_nx(unsigned long addr, int numpages) { return 0; }
> +static inline int set_kernel_memory(char *startp, char *endp,
> +                                   int (*set_memory)(unsigned long start,
> +                                                     int num_pages))
> +{
> +       return 0;
> +}
>  #endif
>
>  #if defined(CONFIG_64BIT) && defined(CONFIG_STRICT_KERNEL_RWX)
> --
> 2.30.2
>
>
> _______________________________________________
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> linux-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv


Reviewed-by: Atish Patra <atish.patra@wdc.com>

-- 
Regards,
Atish