Re: [RFC PATCH 1/5] efi: Move arm-stub to a common file

From: Atish Patra
Date: Wed Feb 26 2020 - 20:17:04 EST

On Wed, 2020-02-26 at 08:04 +0100, Ard Biesheuvel wrote:
> Hi Atish,
>
> On Wed, 26 Feb 2020 at 02:10, Atish Patra <atish.patra@xxxxxxx>
> wrote:
> > Most of the arm-stub code is written in an architecture independent
> > manner.
> > As a result, RISC-V can reuse most of the arm-stub code.
> >
> > Rename the arm-stub.c to efi-stub.c so that ARM, ARM64 and RISC-V
> > can use it.
> > This patch doesn't introduce any functional changes.
> >
> > Signed-off-by: Atish Patra <atish.patra@xxxxxxx>
> > ---
> > arch/arm/Kconfig | 2 +-
> > arch/arm64/Kconfig | 2 +-
> > drivers/firmware/efi/Kconfig | 6 +++---
> > drivers/firmware/efi/libstub/Makefile | 12 ++++++
> > ------
> > .../firmware/efi/libstub/{arm-stub.c => efi-stub.c} | 7 ++++++-
> > 5 files changed, 17 insertions(+), 12 deletions(-)
> > rename drivers/firmware/efi/libstub/{arm-stub.c => efi-stub.c}
> > (98%)
> >
> > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> > index 97864aabc2a6..9931fea06076 100644
> > --- a/arch/arm/Kconfig
> > +++ b/arch/arm/Kconfig
> > @@ -1955,7 +1955,7 @@ config EFI
> > select UCS2_STRING
> > select EFI_PARAMS_FROM_FDT
> > select EFI_STUB
> > - select EFI_ARMSTUB
> > + select EFI_GENERIC_ARCH_STUB
> > select EFI_RUNTIME_WRAPPERS
> > ---help---
> > This option provides support for runtime services
> > provided
> > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> > index 0b30e884e088..ae776d8ef2f9 100644
> > --- a/arch/arm64/Kconfig
> > +++ b/arch/arm64/Kconfig
> > @@ -1720,7 +1720,7 @@ config EFI
> > select EFI_PARAMS_FROM_FDT
> > select EFI_RUNTIME_WRAPPERS
> > select EFI_STUB
> > - select EFI_ARMSTUB
> > + select EFI_GENERIC_ARCH_STUB
> > default y
> > help
> > This option provides support for runtime services
> > provided
> > diff --git a/drivers/firmware/efi/Kconfig
> > b/drivers/firmware/efi/Kconfig
> > index ecc83e2f032c..1bcedb7812da 100644
> > --- a/drivers/firmware/efi/Kconfig
> > +++ b/drivers/firmware/efi/Kconfig
> > @@ -106,12 +106,12 @@ config EFI_PARAMS_FROM_FDT
> > config EFI_RUNTIME_WRAPPERS
> > bool
> >
> > -config EFI_ARMSTUB
> > +config EFI_GENERIC_ARCH_STUB
>
> Let's call it EFI_GENERIC_STUB
>
> > bool
> >
> > -config EFI_ARMSTUB_DTB_LOADER
> > +config EFI_STUB_DTB_LOADER
> > bool "Enable the DTB loader"
> > - depends on EFI_ARMSTUB
> > + depends on EFI_GENERIC_ARCH_STUB
>
> Do you actually need the DTB loader? I feel adding this for ARM was a
> mistake, so you may want to make this depend on !RISCV while you're
> at
> it.
>

Actually we don't need it RISC-V. I think I added that that's a valid
option to have. But your recent cleaup seems otherwise. I will make it
depend on !RISCV. It also doesn't make sense to rename it to
EFI_STUB_DTB_LOADER. So I will just leave EFI_ARMSTUB_DTB_LOADER as it
is.

> > default y
> > help
> > Select this config option to add support for the dtb=
> > command
> > diff --git a/drivers/firmware/efi/libstub/Makefile
> > b/drivers/firmware/efi/libstub/Makefile
> > index 4d6246c6f651..2c5b76787126 100644
> > --- a/drivers/firmware/efi/libstub/Makefile
> > +++ b/drivers/firmware/efi/libstub/Makefile
> > @@ -22,7 +22,7 @@ cflags-$(CONFIG_ARM) := $(subst
> > $(CC_FLAGS_FTRACE),,$(KBUILD_CFLAGS)) \
> > -fno-builtin -fpic \
> > $(call cc-option,-mno-single-
> > pic-base)
> >
> > -cflags-$(CONFIG_EFI_ARMSTUB) += -I$(srctree)/scripts/dtc/libfdt
> > +cflags-$(CONFIG_EFI_GENERIC_ARCH_STUB) +=
> > -I$(srctree)/scripts/dtc/libfdt
> >
> > KBUILD_CFLAGS := $(cflags-y)
> > -DDISABLE_BRANCH_PROFILING \
> > -include
> > $(srctree)/drivers/firmware/efi/libstub/hidden.h \
> > @@ -44,13 +44,13 @@ lib-y := efi-
> > stub-helper.o gop.o secureboot.o tpm.o \
> > skip_spaces.o lib-cmdline.o lib-
> > ctype.o
> >
> > # include the stub's generic dependencies from lib/ when building
> > for ARM/arm64
> > -arm-deps-y := fdt_rw.c fdt_ro.c fdt_wip.c fdt.c fdt_empty_tree.c
> > fdt_sw.c
> > +efi-deps-y := fdt_rw.c fdt_ro.c fdt_wip.c fdt.c fdt_empty_tree.c
> > fdt_sw.c
> >
> > $(obj)/lib-%.o: $(srctree)/lib/%.c FORCE
> > $(call if_changed_rule,cc_o_c)
> >
> > -lib-$(CONFIG_EFI_ARMSTUB) += arm-stub.o fdt.o string.o \
> > - $(patsubst %.c,lib-%.o,$(arm-
> > deps-y))
> > +lib-$(CONFIG_EFI_GENERIC_ARCH_STUB) += efi-stub.o fdt.o
> > string.o \
> > + $(patsubst %.c,lib-%.o,$(efi-
> > deps-y))
> >
> > lib-$(CONFIG_ARM) += arm32-stub.o
> > lib-$(CONFIG_ARM64) += arm64-stub.o
> > @@ -72,8 +72,8 @@ CFLAGS_arm64-stub.o :=
> > -DTEXT_OFFSET=$(TEXT_OFFSET)
> > # a verification pass to see if any absolute relocations exist in
> > any of the
> > # object files.
> > #
> > -extra-$(CONFIG_EFI_ARMSTUB) := $(lib-y)
> > -lib-$(CONFIG_EFI_ARMSTUB) := $(patsubst %.o,%.stub.o,$(lib-
> > y))
> > +extra-$(CONFIG_EFI_GENERIC_ARCH_STUB) := $(lib-y)
> > +lib-$(CONFIG_EFI_GENERIC_ARCH_STUB) := $(patsubst
> > %.o,%.stub.o,$(lib-y))
> >
> > STUBCOPY_FLAGS-$(CONFIG_ARM64) += --prefix-alloc-sections=.init \
> > --prefix-symbols=__efistub_
> > diff --git a/drivers/firmware/efi/libstub/arm-stub.c
> > b/drivers/firmware/efi/libstub/efi-stub.c
> > similarity index 98%
> > rename from drivers/firmware/efi/libstub/arm-stub.c
> > rename to drivers/firmware/efi/libstub/efi-stub.c
> > index 13559c7e6643..b87c3f70430c 100644
> > --- a/drivers/firmware/efi/libstub/arm-stub.c
> > +++ b/drivers/firmware/efi/libstub/efi-stub.c
> > @@ -15,6 +15,7 @@
> >
> > #include "efistub.h"
> >
> > +#if IS_ENABLED(CONFIG_ARM64) || IS_ENABLED(CONFIG_ARM)
> > /*
> > * This is the base address at which to start allocating virtual
> > memory ranges
> > * for UEFI Runtime Services. This is in the low TTBR0 range so
> > that we can use
> > @@ -27,6 +28,10 @@
> > * entire footprint of the UEFI runtime services memory regions)
> > */
> > #define EFI_RT_VIRTUAL_BASE SZ_512M
> > +#else
> > +#define EFI_RT_VIRTUAL_BASE SZ_2G
> > +#endif
> > +
>
> Can we drop this hunk for now? It should be part of your runtime
> services series.
>

Sure. Will do it.

> > #define EFI_RT_VIRTUAL_SIZE SZ_512M
> >
> > #ifdef CONFIG_ARM64
> > @@ -243,7 +248,7 @@ efi_status_t efi_entry(efi_handle_t handle,
> > efi_system_table_t *sys_table_arg)
> > * 'dtb=' unless UEFI Secure Boot is disabled. We assume
> > that secure
> > * boot is enabled if we can't determine its state.
> > */
> > - if (!IS_ENABLED(CONFIG_EFI_ARMSTUB_DTB_LOADER) ||
> > + if (!IS_ENABLED(CONFIG_EFI_STUB_DTB_LOADER) ||
> > secure_boot != efi_secureboot_mode_disabled) {
> > if (strstr(cmdline_ptr, "dtb="))
> > pr_efi("Ignoring DTB from command
> > line.\n");
> > --
> > 2.24.0
> >

--
Regards,
Atish