Mark kernel page as read-only

Mark kernel page as read-only

[catalin.vasile]

Hi,

I have some pages allocated through __get_free_pages(). Is there a way to set such a page's protection to be read-only? I am working with an octeon2 mips platform.

Best regards,
Catalin Vasile
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Date:   Thu, 28 Jun 2018 10:44:39 -0700
From:   Paul Burton <paul.burton@mips.com>
To:     catalin.vasile@keysight.com
Cc:     linux-mips@linux-mips.org
Subject: Re: Mark kernel page as read-only
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Hi Catalin,

On Thu, Jun 28, 2018 at 10:53:22AM +0000, catalin.vasile@keysight.com wrote:
> I have some pages allocated through __get_free_pages(). Is there a way
> to set such a page's protection to be read-only? I am working with an
> octeon2 mips platform.

__get_free_pages() is going to give you a virtual address in the
unmapped (c)kseg0 segment, which you cannot modify the protection of.

One option might be to switch away from __get_free_pages() towards using
alloc_pages(), followed by vmap() with a read-only prot argument.

Thanks,
    Paul

Mark kernel page as read-only

[catalin.vasile]

Hi,

I have some pages allocated through __get_free_pages(). Is there a way to set such a page's protection to be read-only? I am working with an octeon2 mips platform.

Best regards,
Catalin Vasile

Re: Mark kernel page as read-only

[Paul Burton]

Hi Catalin,

On Thu, Jun 28, 2018 at 10:53:22AM +0000, catalin.vasile@keysight.com wrote:
> I have some pages allocated through __get_free_pages(). Is there a way
> to set such a page's protection to be read-only? I am working with an
> octeon2 mips platform.

__get_free_pages() is going to give you a virtual address in the
unmapped (c)kseg0 segment, which you cannot modify the protection of.

One option might be to switch away from __get_free_pages() towards using
alloc_pages(), followed by vmap() with a read-only prot argument.

Thanks,
    Paul