Re: [PATCH] x86/boot: efistub: Assign global boot_params variable

[Ingo Molnar <mingo@kernel.org>]

* Ard Biesheuvel <ardb@kernel.org> wrote:

> On Mon, 16 Oct 2023 at 18:46, Ard Biesheuvel <ardb@google.com> wrote:
> >
> > From: Ard Biesheuvel <ardb@kernel.org>
> >
> > Now that the x86 EFI stub calls into some APIs exposed by the
> > decompressor (e.g., kaslr_get_random_long()), it is necessary to ensure
> > that the global boot_params variable is set correctly before doing so.
> >
> > Note that the decompressor and the kernel proper carry conflicting
> > declarations for the global variable 'boot_params' so refer to it via an
> > alias to work around this.
> >
> > Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
> > ---
> >  drivers/firmware/efi/libstub/x86-stub.c | 3 +++
> >  1 file changed, 3 insertions(+)
> >
> > diff --git a/drivers/firmware/efi/libstub/x86-stub.c b/drivers/firmware/efi/libstub/x86-stub.c
> > index 3bfc59637dd1..51407207ded5 100644
> > --- a/drivers/firmware/efi/libstub/x86-stub.c
> > +++ b/drivers/firmware/efi/libstub/x86-stub.c
> > @@ -812,12 +812,15 @@ void __noreturn efi_stub_entry(efi_handle_t handle,
> >                                efi_system_table_t *sys_table_arg,
> >                                struct boot_params *boot_params)
> >  {
> > +       extern struct boot_params *bpp asm("boot_params");
> 
> I am getting hatemail from the bots about this extern declaration, so
> I will move that into x86-stub.h.

Hm, it would be better if we moved all of x86-stub.h into 
arch/x86/include/asm/ or so. We don't really encourage "deep" driver-level 
exports like that, and there's little reason why this couldn't be in the 
x86 headers, right?

> Unless anyone minds, I'll queue this up and send it to Linus myself
> via the EFI fixes branch.

Other than the above:

  Acked-by: Ingo Molnar <mingo@kernel.org>

Thanks,

	Ingo