On 27 October 2015 at 06:11, Matt Fleming [off-list ref] wrote:

On Fri, 23 Oct, at 04:48:14PM, Ard Biesheuvel wrote:

quoted

Now that we added special handling to the C files in libstub, move
the one remaining arm64 specific EFI stub C file to libstub as
well, so that it gets the same treatment. This should prevent future
changes from resulting in binaries that may execute incorrectly in
UEFI context.

Sorry, I'm coming at this cache-cold: What special handling was added
to libstub that you want to make use of here?

This is about the libstub patches that you reviewed ~2 weeks ago and
that have been queued in Catalin's arm64 tree for 4.4

quoted

With efi-entry.S the only remaining EFI stub source file under
arch/arm64, we can also simplify the Makefile logic somewhat.

Signed-off-by: Ard Biesheuvel <redacted>
---

I would like to suggest that this be taken on top of the stuff that is
queued for 4.4 at the moment (if it is not too late already).

That's upto the tip folks (Cc'd). Ingo, would you consider applying
a minimal build cleanup patch like this for v4.4?

Actually, the suggestion was aimed at Catalin, who has all the libstub
and KASAN patches queued that this patch depends on.
Apologies for the confusion.

Thanks,
Ard.

quoted

 arch/arm64/kernel/Makefile                                                | 9 ++-------
 drivers/firmware/efi/libstub/Makefile                                     | 3 +++
 arch/arm64/kernel/efi-stub.c => drivers/firmware/efi/libstub/arm64-stub.c | 0
 3 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile
index 1b6bda2ff102..474691f8b13a 100644
--- a/arch/arm64/kernel/Makefile
+++ b/arch/arm64/kernel/Makefile

@@ -4,11 +4,8 @@

 CPPFLAGS_vmlinux.lds := -DTEXT_OFFSET=$(TEXT_OFFSET)
 AFLAGS_head.o                := -DTEXT_OFFSET=$(TEXT_OFFSET)
-CFLAGS_efi-stub.o    := -DTEXT_OFFSET=$(TEXT_OFFSET)
 CFLAGS_armv8_deprecated.o := -I$(src)

-KASAN_SANITIZE_efi-stub.o    := n
-
 CFLAGS_REMOVE_ftrace.o = -pg
 CFLAGS_REMOVE_insn.o = -pg
 CFLAGS_REMOVE_return_address.o = -pg

@@ -22,9 +19,7 @@ arm64-obj-y         := debug-monitors.o entry.o irq.o fpsimd.o              \
                         cpufeature.o alternative.o cacheinfo.o               \
                         smp.o smp_spin_table.o topology.o

-stub-obj                             := efi-stub.o efi-entry.o
-extra-y                                      := $(stub-obj)
-stub-obj                             := $(patsubst %.o,%.stub.o,$(stub-obj))
+extra-$(CONFIG_EFI)                  := efi-entry.o

 OBJCOPYFLAGS := --prefix-symbols=__efistub_
 $(obj)/%.stub.o: $(obj)/%.o FORCE

@@ -42,7 +37,7 @@ arm64-obj-$(CONFIG_CPU_PM)          += sleep.o suspend.o
 arm64-obj-$(CONFIG_CPU_IDLE)         += cpuidle.o
 arm64-obj-$(CONFIG_JUMP_LABEL)               += jump_label.o
 arm64-obj-$(CONFIG_KGDB)             += kgdb.o
-arm64-obj-$(CONFIG_EFI)                      += efi.o $(stub-obj)
+arm64-obj-$(CONFIG_EFI)                      += efi.o efi-entry.stub.o
 arm64-obj-$(CONFIG_PCI)                      += pci.o
 arm64-obj-$(CONFIG_ARMV8_DEPRECATED) += armv8_deprecated.o
 arm64-obj-$(CONFIG_ACPI)             += acpi.o

diff --git a/drivers/firmware/efi/libstub/Makefile b/drivers/firmware/efi/libstub/Makefile
index bca9a76cbd33..92ae557abbbc 100644
--- a/drivers/firmware/efi/libstub/Makefile
+++ b/drivers/firmware/efi/libstub/Makefile

@@ -34,6 +34,9 @@ $(obj)/lib-%.o: $(srctree)/lib/%.c FORCE
 lib-$(CONFIG_EFI_ARMSTUB)    += arm-stub.o fdt.o string.o \
                                 $(patsubst %.c,lib-%.o,$(arm-deps))

+lib-$(CONFIG_ARM64)          += arm64-stub.o
+CFLAGS_arm64-stub.o          := -DTEXT_OFFSET=$(TEXT_OFFSET)
+
 #
 # arm64 puts the stub in the kernel proper, which will unnecessarily retain all
 # code indefinitely unless it is annotated as __init/__initdata/__initconst etc.

diff --git a/arch/arm64/kernel/efi-stub.c b/drivers/firmware/efi/libstub/arm64-stub.c
similarity index 100%
rename from arch/arm64/kernel/efi-stub.c
rename to drivers/firmware/efi/libstub/arm64-stub.c
--

2.1.4