On Thu, 10 Sep 2020 07:08:07 PDT (-0700), ardb@xxxxxxxxxx wrote:
On Thu, 10 Sep 2020 at 13:04, Ard Biesheuvel <ardb@xxxxxxxxxx> wrote:
On Thu, 10 Sep 2020 at 04:34, Atish Patra <atishp@xxxxxxxxxxxxxx> wrote:
>
> On Wed, Sep 9, 2020 at 2:44 PM Atish Patra <atishp@xxxxxxxxxxxxxx> wrote:
> >
> > On Wed, Sep 9, 2020 at 1:52 PM Palmer Dabbelt <palmer@xxxxxxxxxxx> wrote:
> > >
> > > On Wed, 09 Sep 2020 08:16:20 PDT (-0700), ardb@xxxxxxxxxx wrote:
> > > > Maxim reports boot failures on platforms that describe reserved memory
> > > > regions in DT that are disjoint from system DRAM, and which are converted
> > > > to EfiReservedMemory regions by the EFI subsystem in u-boot.
> > > >
> > > > As it turns out, the whole notion of discovering the base of DRAM is
> > > > problematic, and it would be better to simply rely on the EFI memory
> > > > allocation routines instead, and derive the FDT and initrd allocation
> > > > limits from the actual placement of the kernel (which is what defines
> > > > the start of the linear region anyway)
> > > >
> > > > Finally, we should be able to get rid of get_dram_base() entirely.
> > > > However, as RISC-V only just started using it, we will need to address
> > > > that at a later time.
> > >
> > > Looks like we're using dram_base to derive two argumets to
> > > efi_relocate_kernel(): the preferred load address and the minimum load address.
> > > I don't see any reason why we can't use the same PAGE_OFFSET-like logic that
> > > x86 uses for the minimum load address, but I don't think we have any mechanism
> > > like "struct boot_params" so we'd need to come up with something.
> > >
> >
> > As discussed in the other thread
> > (https://www.spinics.net/lists/linux-efi/msg20262.html),
> > we don't need to do anything special. efi_relocate_kernel can just
> > take preferred address as 0
> > so that efi_bs_alloc will fail and efi_low_alloc_above will be used to
> > allocate 2MB/4MB aligned address as per requirement.
> >
> > I don't think the other changes in this series will cause any issue
> > for RISC-V. I will test it and update anyways.
> >
> > > > Cc: Maxim Uvarov <maxim.uvarov@xxxxxxxxxx>
> > > > Cc: Heinrich Schuchardt <xypron.glpk@xxxxxx>
> > > > Cc: Atish Patra <atish.patra@xxxxxxx>
> > > > Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
> > > > Cc: Jens Wiklander <jens.wiklander@xxxxxxxxxx>
> > > > Cc: Francois Ozog <francois.ozog@xxxxxxxxxx>
> > > > Cc: Etienne CARRIERE <etienne.carriere@xxxxxx>
> > > > Cc: Takahiro Akashi <takahiro.akashi@xxxxxxxxxx>
> > > > Cc: Patrice CHOTARD <patrice.chotard@xxxxxx>
> > > > Cc: Sumit Garg <sumit.garg@xxxxxxxxxx>
> > > > Cc: Grant Likely <Grant.Likely@xxxxxxx>
> > > > Cc: Ilias Apalodimas <ilias.apalodimas@xxxxxxxxxx>
> > > > Cc: Christophe Priouzeau <christophe.priouzeau@xxxxxxxxxx>
> > > > Cc: Rouven Czerwinski <r.czerwinski@xxxxxxxxxxxxxx>
> > > > Cc: Patrick DELAUNAY <patrick.delaunay@xxxxxx>
> > > >
> > > > Ard Biesheuvel (3):
> > > > efi/libstub: Export efi_low_alloc_above() to other units
> > > > efi/libstub: Use low allocation for the uncompressed kernel
> > > > efi/libstub: base FDT and initrd placement on image address not DRAM
> > > > base
> > > >
> > > > arch/arm/include/asm/efi.h | 6 +-
> > > > arch/arm64/include/asm/efi.h | 2 +-
> > > > drivers/firmware/efi/libstub/arm32-stub.c | 177 ++++----------------
> > > > drivers/firmware/efi/libstub/efi-stub.c | 2 +-
> > > > drivers/firmware/efi/libstub/efistub.h | 3 +
> > > > drivers/firmware/efi/libstub/relocate.c | 4 +-
> > > > 6 files changed, 47 insertions(+), 147 deletions(-)
> >
>
> I verified the above patches along with the following RISC-V specific changes.
>
> diff --git a/arch/riscv/include/asm/efi.h b/arch/riscv/include/asm/efi.h
> index 93c305a638f4..dd6ceea9d548 100644
> --- a/arch/riscv/include/asm/efi.h
> +++ b/arch/riscv/include/asm/efi.h
> @@ -37,7 +37,7 @@ static inline unsigned long
> efi_get_max_fdt_addr(unsigned long dram_base)
> static inline unsigned long efi_get_max_initrd_addr(unsigned long dram_base,
> unsigned long image_addr)
> {
> - return dram_base + SZ_256M;
> + return image_addr + SZ_256M;
> }
>
Ah yes, we need this change as well - this is a bit unfortunate since
that creates a conflict with the RISC-V tree.
> --- a/drivers/firmware/efi/libstub/riscv-stub.c
> +++ b/drivers/firmware/efi/libstub/riscv-stub.c
> @@ -100,7 +100,7 @@ efi_status_t handle_kernel_image(unsigned long *image_addr,
> */
> preferred_addr = round_up(dram_base, MIN_KIMG_ALIGN) + MIN_KIMG_ALIGN;
> status = efi_relocate_kernel(image_addr, kernel_size, *image_size,
> - preferred_addr, MIN_KIMG_ALIGN, dram_base);
> + 0, MIN_KIMG_ALIGN, 0);
>
> FWIW: Tested-by: Atish Patra <atish.patra@xxxxxxx>
Thanks for confirming.
OK,
So, just to annoy Palmer and you more than I already have up to this
point: any chance we could do a final respin of the RISC-V code on top
of these changes? They are important for ARM, and I would prefer these
to be merged in a way that makes it easy to backport them to -stable
if needed.
So what I would suggest is:
- I will create a new 'shared-efi' tag/stable branch containing the
existing two patches, as well as these changes (in a slightly updated
form)
- Palmer creates a new topic branch in the riscv repo based on this
shared tag, and applies the [updated] RISC-V patches on top
- Palmer drops the current version of the riscv patches from
riscv/for-next, and merges the topic branch into it instead.
Again, sorry to be a pain, but I think this is the cleanest way to get
these changes queued up for v5.10 without painting ourselves into a
corner too much when it comes to future follow-up changes.
That's fine for me.
