Re: [PATCH] riscv: Protect kernel linear mapping only if CONFIG_STRICT_KERNEL_RWX is set

[Palmer Dabbelt]

On Sat, 17 Apr 2021 10:26:36 PDT (-0700), alex@xxxxxxxx wrote:
> Le 4/16/21 à 12:33 PM, Palmer Dabbelt a écrit :
> > On Fri, 16 Apr 2021 03:47:19 PDT (-0700), alex@xxxxxxxx wrote:
> > > Hi Anup,
> > >
> > > Le 4/16/21 à 6:41 AM, Anup Patel a écrit :
> > > > On Thu, Apr 15, 2021 at 4:34 PM Alexandre Ghiti <alex@xxxxxxxx> wrote:
> > > > > If CONFIG_STRICT_KERNEL_RWX is not set, we cannot set different
> > > > > permissions
> > > > > to the kernel data and text sections, so make sure it is defined before
> > > > > trying to protect the kernel linear mapping.
> > > > >
> > > > > Signed-off-by: Alexandre Ghiti <alex@xxxxxxxx>
> > > >
> > > > Maybe you should add "Fixes:" tag in commit tag ?
> > >
> > > Yes you're right I should have done that. Maybe Palmer will squash it as
> > > it just entered for-next?
> >
> > Ya, I'll do it.  My testing box was just tied up last night for the rc8
> > PR, so I threw this on for-next to get the buildbots to take a look.
> > It's a bit too late to take something for this week, as I try to be
> > pretty conservative this late in the cycle.  There's another kprobes fix
> > on the list so if we end up with an rc8 I might send this along with
> > that, otherwise this'll just go onto for-next before the linear map
> > changes that exercise the bug.
> >
> > You're more than welcome to just dig up the fixes tag and reply, my
> > scripts pull all tags from replies (just like Revieweb-by).  Otherwise
> > I'll do it myself, most people don't really post Fixes tags that
> > accurately so I go through it for pretty much everything anyway.
>
> Here it is:
>
> Fixes: 4b67f48da707 ("riscv: Move kernel mapping outside of linear mapping")

Thanks.  I just squashed it, though, as I had to rewrite this anyway.

> Thanks,
>
> > Thanks for sorting this out so quickly!
> >
> > > > Otherwise it looks good.
> > > >
> > > > Reviewed-by: Anup Patel <anup@xxxxxxxxxxxxxx>
> > >
> > > Thank you!
> > >
> > > Alex
> > >
> > > > Regards,
> > > > Anup
> > > >
> > > > > ---
> > > > >   arch/riscv/kernel/setup.c | 8 ++++----
> > > > >   1 file changed, 4 insertions(+), 4 deletions(-)
> > > > >
> > > > > diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
> > > > > index 626003bb5fca..ab394d173cd4 100644
> > > > > --- a/arch/riscv/kernel/setup.c
> > > > > +++ b/arch/riscv/kernel/setup.c
> > > > > @@ -264,12 +264,12 @@ void __init setup_arch(char **cmdline_p)
> > > > >
> > > > >          sbi_init();
> > > > >
> > > > > -       if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX))
> > > > > +       if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)) {
> > > > >                  protect_kernel_text_data();
> > > > > -
> > > > > -#if defined(CONFIG_64BIT) && defined(CONFIG_MMU)
> > > > > -       protect_kernel_linear_mapping_text_rodata();
> > > > > +#ifdef CONFIG_64BIT
> > > > > +               protect_kernel_linear_mapping_text_rodata();
> > > > >   #endif
> > > > > +       }
> > > > >
> > > > >   #ifdef CONFIG_SWIOTLB
> > > > >          swiotlb_init(1);
> > > > > --
> > > > > 2.20.1
> > > >
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> >
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