Re: [PATCH v3 2/6] arm64/mirror: arm64 enabling - find mirrored memory ranges

[Kefeng Wang]

On 2022/6/10 17:34, Ard Biesheuvel wrote:
> On Fri, 10 Jun 2022 at 11:27, Kefeng Wang <wangkefeng.wang@xxxxxxxxxx> wrote:
> > On 2022/6/7 17:38, Wupeng Ma wrote:
> > > From: Ma Wupeng <mawupeng1@xxxxxxxxxx>
> > >
> > > Commit b05b9f5f9dcf ("x86, mirror: x86 enabling - find mirrored memory ranges")
> > > introduced mirrored memory support for x86 and this could be used on arm64.
> > >
> > > Since we only support this feature on arm64, efi_find_mirror() won't be placed
> > > into efi_init(), which is used by riscv/arm/arm64, it is added in setup_arch()
> > > to scan the memory map and mark mirrored memory in memblock.
> > Move into efi_init() looks better, it won't bring negative effects on
> > arm/riscv.
> >
> > but let's maintainer to make a decision.
> >
> > Reviewed-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
> I don't disagree with that in principle, but x86 calls the efi fake
> memmap stuff between efi_init() and efi_find_mirror(), and I already
> indicated that I don't want to enable fake memmap on !X86.

I mean move into efi_init() in drivers/firmware/efi/efi-init.c which 
only used

in arm32/arm64/riscv.

> But I do think there is some room for improvement here: we could move
> things like efi_mokvar_table_init() and efi_esrt_init() into
> efi_init() as well, and make efi_fake_memmap() do nothing on !X86 so
> we can move it into efi_init() too.

x86 has own efi_init() in arch/x86/platform/efi/efi.c, it seams that all 
the above

function could move into x86's own efi_init(), not sure, but we could do 
it later

if it possible.

> > > Signed-off-by: Ma Wupeng <mawupeng1@xxxxxxxxxx>
> > > ---
> > >    Documentation/admin-guide/kernel-parameters.txt | 2 +-
> > >    arch/arm64/kernel/setup.c                       | 1 +
> > >    2 files changed, 2 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> > > index 8090130b544b..e3537646b6f7 100644
> > > --- a/Documentation/admin-guide/kernel-parameters.txt
> > > +++ b/Documentation/admin-guide/kernel-parameters.txt
> > > @@ -2301,7 +2301,7 @@
> > >
> > >        keepinitrd      [HW,ARM]
> > >
> > > -     kernelcore=     [KNL,X86,IA-64,PPC]
> > > +     kernelcore=     [KNL,X86,IA-64,PPC,ARM64]
> > >                        Format: nn[KMGTPE] | nn% | "mirror"
> > >                        This parameter specifies the amount of memory usable by
> > >                        the kernel for non-movable allocations.  The requested
> > > diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
> > > index cf3a759f10d4..6e9acd7ecf0f 100644
> > > --- a/arch/arm64/kernel/setup.c
> > > +++ b/arch/arm64/kernel/setup.c
> > > @@ -328,6 +328,7 @@ void __init __no_sanitize_address setup_arch(char **cmdline_p)
> > >
> > >        xen_early_init();
> > >        efi_init();
> > > +     efi_find_mirror();
> > >
> > >        if (!efi_enabled(EFI_BOOT) && ((u64)_text % MIN_KIMG_ALIGN) != 0)
> > >             pr_warn(FW_BUG "Kernel image misaligned at boot, please fix your bootloader!");
> .