linux-kernel - Re: [PATCH v3 2/3] riscv: Introduce set_kernel

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Message-ID: <CAAhSdy0w4DsGMdWZ3k2Qti0mwQQmFXHbJw2RXbjH+hQ8fPKxfQ@mail.gmail.com>
Date:   Thu, 3 Jun 2021 17:05:46 +0530
From:   Anup Patel <anup@...infault.org>
To:     Alexandre Ghiti <alex@...ti.fr>
Cc:     Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Jisheng Zhang <jszhang@...nel.org>,
        Christoph Hellwig <hch@...radead.org>,
        Zong Li <zong.li@...ive.com>,
        linux-riscv <linux-riscv@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org List" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 2/3] riscv: Introduce set_kernel_memory helper

On Thu, Jun 3, 2021 at 2:00 PM Alexandre Ghiti <alex@...ti.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@...radead.org>
> Signed-off-by: Alexandre Ghiti <alex@...ti.fr>

Looks good to me.

Reviewed-by: Anup Patel <anup@...infault.org>

Regards,
Anup

> ---
>  arch/riscv/include/asm/set_memory.h |  5 +++++
>  arch/riscv/mm/pageattr.c            | 10 ++++++++++
>  2 files changed, 15 insertions(+)
>
> diff --git a/arch/riscv/include/asm/set_memory.h b/arch/riscv/include/asm/set_memory.h
> index 086f757e8ba3..7a411fed9e0e 100644
> --- a/arch/riscv/include/asm/set_memory.h
> +++ b/arch/riscv/include/asm/set_memory.h
> @@ -16,6 +16,7 @@ int set_memory_rw(unsigned long addr, int numpages);
>  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);
> +int set_kernel_memory(char *start, char *end, int (*set_memory)(unsigned long, int));
>  void protect_kernel_text_data(void);
>  #else
>  static inline int set_memory_ro(unsigned long addr, int numpages) { return 0; }
> @@ -24,6 +25,10 @@ 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 *start, char *end, int (*set_memory)(unsigned long, int))
> +{
> +       return 0;
> +}
>  #endif
>
>  #if defined(CONFIG_64BIT) && defined(CONFIG_STRICT_KERNEL_RWX)
> diff --git a/arch/riscv/mm/pageattr.c b/arch/riscv/mm/pageattr.c
> index 5e49e4b4a4cc..c47ac6a432ac 100644
> --- a/arch/riscv/mm/pageattr.c
> +++ b/arch/riscv/mm/pageattr.c
> @@ -156,6 +156,16 @@ int set_memory_nx(unsigned long addr, int numpages)
>         return __set_memory(addr, numpages, __pgprot(0), __pgprot(_PAGE_EXEC));
>  }
>
> +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);
> +}
> +
>  int set_direct_map_invalid_noflush(struct page *page)
>  {
>         int ret;
> --
> 2.30.2
>