arm64: get rid of TEXT_OFFSET

TEXT_OFFSET serves no purpose, and for this reason, it was redefined
as 0x0 in the v5.8 timeframe. Since this does not appear to have caused
any issues

arm64: get rid of TEXT_OFFSET

TEXT_OFFSET serves no purpose, and for this reason, it was redefined
as 0x0 in the v5.8 timeframe. Since this does not appear to have caused
any issues that require us to revisit that decision, let's get rid of the
macro entirely, along with any references to it.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20200825135440.11288-1-ardb@kernel.org
Signed-off-by: Will Deacon <will@kernel.org>

show more ...

efi/libstub: Disable -mbranch-protection

In preparation for adding --orphan-handling=warn to more architectures,
disable -mbranch-protection, as EFI does not yet support it[1]. This was

efi/libstub: Disable -mbranch-protection

In preparation for adding --orphan-handling=warn to more architectures,
disable -mbranch-protection, as EFI does not yet support it[1]. This was
noticed due to it producing unwanted .note.gnu.property sections (prefixed
with .init due to the objcopy build step).

However, we must also work around a bug in Clang where the section is
still emitted for code-less object files[2], so also remove the section
during the objcopy.

[1] https://lore.kernel.org/lkml/CAMj1kXHck12juGi=E=P4hWP_8vQhQ+-x3vBMc3TGeRWdQ-XkxQ@mail.gmail.com
[2] https://bugs.llvm.org/show_bug.cgi?id=46480

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20200821194310.3089815-8-keescook@chromium.org

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x86/boot/compressed: Force hidden visibility for all symbol references

Eliminate all GOT entries in the decompressor binary, by forcing hidden
visibility for all symbol references, which

x86/boot/compressed: Force hidden visibility for all symbol references

Eliminate all GOT entries in the decompressor binary, by forcing hidden
visibility for all symbol references, which informs the compiler that
such references will be resolved at link time without the need for
allocating GOT entries.

To ensure that no GOT entries will creep back in, add an assertion to
the decompressor linker script that will fire if the .got section has
a non-zero size.

[Arvind: move hidden.h to include/linux instead of making a copy]

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200731230820.1742553-3-keescook@chromium.org

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Merge tag 'kbuild-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

- run the checker (e.g. sparse) after the

Merge tag 'kbuild-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

- run the checker (e.g. sparse) after the compiler

- remove unneeded cc-option tests for old compiler flags

- fix tar-pkg to install dtbs

- introduce ccflags-remove-y and asflags-remove-y syntax

- allow to trace functions in sub-directories of lib/

- introduce hostprogs-always-y and userprogs-always-y syntax

- various Makefile cleanups

* tag 'kbuild-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
kbuild: stop filtering out $(GCC_PLUGINS_CFLAGS) from cc-option base
kbuild: include scripts/Makefile.* only when relevant CONFIG is enabled
kbuild: introduce hostprogs-always-y and userprogs-always-y
kbuild: sort hostprogs before passing it to ifneq
kbuild: move host .so build rules to scripts/gcc-plugins/Makefile
kbuild: Replace HTTP links with HTTPS ones
kbuild: trace functions in subdirectories of lib/
kbuild: introduce ccflags-remove-y and asflags-remove-y
kbuild: do not export LDFLAGS_vmlinux
kbuild: always create directories of targets
powerpc/boot: add DTB to 'targets'
kbuild: buildtar: add dtbs support
kbuild: remove cc-option test of -ffreestanding
kbuild: remove cc-option test of -fno-stack-protector
Revert "kbuild: Create directory for target DTB"
kbuild: run the checker after the compiler

show more ...

efi: Revert "efi/x86: Fix build with gcc 4"

This reverts commit 5435f73d5c4a1b75, which is no longer needed now
that the minimum GCC version has been bumped to v4.9

Signed-off-b

efi: Revert "efi/x86: Fix build with gcc 4"

This reverts commit 5435f73d5c4a1b75, which is no longer needed now
that the minimum GCC version has been bumped to v4.9

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

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kbuild: remove cc-option test of -ffreestanding

Some Makefiles already pass -ffreestanding unconditionally.
For example, arch/arm64/lib/Makefile, arch/x86/purgatory/Makefile.

No

kbuild: remove cc-option test of -ffreestanding

Some Makefiles already pass -ffreestanding unconditionally.
For example, arch/arm64/lib/Makefile, arch/x86/purgatory/Makefile.

No problem report so far about hard-coding this option. So, we can
assume all supported compilers know -ffreestanding.

I confirmed GCC 4.8 and Clang manuals document this option.

Get rid of cc-option from -ffreestanding.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>

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kbuild: remove cc-option test of -fno-stack-protector

Some Makefiles already pass -fno-stack-protector unconditionally.
For example, arch/arm64/kernel/vdso/Makefile, arch/x86/xen/Makefil

kbuild: remove cc-option test of -fno-stack-protector

Some Makefiles already pass -fno-stack-protector unconditionally.
For example, arch/arm64/kernel/vdso/Makefile, arch/x86/xen/Makefile.

No problem report so far about hard-coding this option. So, we can
assume all supported compilers know -fno-stack-protector.

GCC 4.8 and Clang support this option (https://godbolt.org/z/_HDGzN)

Get rid of cc-option from -fno-stack-protector.

Remove CONFIG_CC_HAS_STACKPROTECTOR_NONE, which is always 'y'.

Note:
arch/mips/vdso/Makefile adds -fno-stack-protector twice, first
unconditionally, and second conditionally. I removed the second one.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>

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efi/x86: Fix build with gcc 4

Commit

bbf8e8b0fe04 ("efi/libstub: Optimize for size instead of speed")

changed the optimization level for the EFI stub to -Os from -O2.

efi/x86: Fix build with gcc 4

Commit

bbf8e8b0fe04 ("efi/libstub: Optimize for size instead of speed")

changed the optimization level for the EFI stub to -Os from -O2.

Andrey Ignatov reports that this breaks the build with gcc 4.8.5.

Testing on godbolt.org, the combination of -Os,
-fno-asynchronous-unwind-tables, and ms_abi functions doesn't work,
failing with the error:
sorry, unimplemented: ms_abi attribute requires
-maccumulate-outgoing-args or subtarget optimization implying it

This does appear to work with gcc 4.9 onwards.

Add -maccumulate-outgoing-args explicitly to unbreak the build with
pre-4.9 versions of gcc.

Reported-by: Andrey Ignatov <rdna@fb.com>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200605150638.1011637-1-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

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Rebase locking/kcsan to locking/urgent

Merge the state of the locking kcsan branch before the read/write_once()
and the atomics modifications got merged.

Squash the fallout of t

Rebase locking/kcsan to locking/urgent

Merge the state of the locking kcsan branch before the read/write_once()
and the atomics modifications got merged.

Squash the fallout of the rebase on top of the read/write once and atomic
fallback work into the merge. The history of the original branch is
preserved in tag locking-kcsan-2020-06-02.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

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Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 updates from Will Deacon:
"A sizeable pile of arm64 updates for 5.8.

Summar

Merge tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

Pull arm64 updates from Will Deacon:
"A sizeable pile of arm64 updates for 5.8.

Summary below, but the big two features are support for Branch Target
Identification and Clang's Shadow Call stack. The latter is currently
arm64-only, but the high-level parts are all in core code so it could
easily be adopted by other architectures pending toolchain support

Branch Target Identification (BTI):

- Support for ARMv8.5-BTI in both user- and kernel-space. This allows
branch targets to limit the types of branch from which they can be
called and additionally prevents branching to arbitrary code,
although kernel support requires a very recent toolchain.

- Function annotation via SYM_FUNC_START() so that assembly functions
are wrapped with the relevant "landing pad" instructions.

- BPF and vDSO updates to use the new instructions.

- Addition of a new HWCAP and exposure of BTI capability to userspace
via ID register emulation, along with ELF loader support for the
BTI feature in .note.gnu.property.

- Non-critical fixes to CFI unwind annotations in the sigreturn
trampoline.

Shadow Call Stack (SCS):

- Support for Clang's Shadow Call Stack feature, which reserves
platform register x18 to point at a separate stack for each task
that holds only return addresses. This protects function return
control flow from buffer overruns on the main stack.

- Save/restore of x18 across problematic boundaries (user-mode,
hypervisor, EFI, suspend, etc).

- Core support for SCS, should other architectures want to use it
too.

- SCS overflow checking on context-switch as part of the existing
stack limit check if CONFIG_SCHED_STACK_END_CHECK=y.

CPU feature detection:

- Removed numerous "SANITY CHECK" errors when running on a system
with mismatched AArch32 support at EL1. This is primarily a concern
for KVM, which disabled support for 32-bit guests on such a system.

- Addition of new ID registers and fields as the architecture has
been extended.

Perf and PMU drivers:

- Minor fixes and cleanups to system PMU drivers.

Hardware errata:

- Unify KVM workarounds for VHE and nVHE configurations.

- Sort vendor errata entries in Kconfig.

Secure Monitor Call Calling Convention (SMCCC):

- Update to the latest specification from Arm (v1.2).

- Allow PSCI code to query the SMCCC version.

Software Delegated Exception Interface (SDEI):

- Unexport a bunch of unused symbols.

- Minor fixes to handling of firmware data.

Pointer authentication:

- Add support for dumping the kernel PAC mask in vmcoreinfo so that
the stack can be unwound by tools such as kdump.

- Simplification of key initialisation during CPU bringup.

BPF backend:

- Improve immediate generation for logical and add/sub instructions.

vDSO:

- Minor fixes to the linker flags for consistency with other
architectures and support for LLVM's unwinder.

- Clean up logic to initialise and map the vDSO into userspace.

ACPI:

- Work around for an ambiguity in the IORT specification relating to
the "num_ids" field.

- Support _DMA method for all named components rather than only PCIe
root complexes.

- Minor other IORT-related fixes.

Miscellaneous:

- Initialise debug traps early for KGDB and fix KDB cacheflushing
deadlock.

- Minor tweaks to early boot state (documentation update, set
TEXT_OFFSET to 0x0, increase alignment of PE/COFF sections).

- Refactoring and cleanup"

* tag 'arm64-upstream' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux: (148 commits)
KVM: arm64: Move __load_guest_stage2 to kvm_mmu.h
KVM: arm64: Check advertised Stage-2 page size capability
arm64/cpufeature: Add get_arm64_ftr_reg_nowarn()
ACPI/IORT: Remove the unused __get_pci_rid()
arm64/cpuinfo: Add ID_MMFR4_EL1 into the cpuinfo_arm64 context
arm64/cpufeature: Add remaining feature bits in ID_AA64PFR1 register
arm64/cpufeature: Add remaining feature bits in ID_AA64PFR0 register
arm64/cpufeature: Add remaining feature bits in ID_AA64ISAR0 register
arm64/cpufeature: Add remaining feature bits in ID_MMFR4 register
arm64/cpufeature: Add remaining feature bits in ID_PFR0 register
arm64/cpufeature: Introduce ID_MMFR5 CPU register
arm64/cpufeature: Introduce ID_DFR1 CPU register
arm64/cpufeature: Introduce ID_PFR2 CPU register
arm64/cpufeature: Make doublelock a signed feature in ID_AA64DFR0
arm64/cpufeature: Drop TraceFilt feature exposure from ID_DFR0 register
arm64/cpufeature: Add explicit ftr_id_isar0[] for ID_ISAR0 register
arm64: mm: Add asid_gen_match() helper
firmware: smccc: Fix missing prototype warning for arm_smccc_version_init
arm64: vdso: Fix CFI directives in sigreturn trampoline
arm64: vdso: Don't prefix sigreturn trampoline with a BTI C instruction
...

show more ...

efi/libstub: Optimize for size instead of speed

Reclaim the bloat from the addition of printf by optimizing the stub for
size. With gcc 9, the text size of the stub is:

ARCH

efi/libstub: Optimize for size instead of speed

Reclaim the bloat from the addition of printf by optimizing the stub for
size. With gcc 9, the text size of the stub is:

ARCH before +printf -Os
arm 35197 37889 34638
arm64 34883 38159 34479
i386 18571 21657 17025
x86_64 25677 29328 22144

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200518190716.751506-6-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

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efi/libstub: Add a basic printf implementation

Copy vsprintf from arch/x86/boot/printf.c to get a simple printf
implementation.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.e

efi/libstub: Add a basic printf implementation

Copy vsprintf from arch/x86/boot/printf.c to get a simple printf
implementation.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200518190716.751506-5-nivedita@alum.mit.edu
[ardb: add some missing braces in if...else clauses]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

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efi/libstub: Disable Shadow Call Stack

Shadow stacks are not available in the EFI stub, filter out SCS flags.

Suggested-by: James Morse <james.morse@arm.com>
Signed-off-by: Sami

efi/libstub: Disable Shadow Call Stack

Shadow stacks are not available in the EFI stub, filter out SCS flags.

Suggested-by: James Morse <james.morse@arm.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>

show more ...

efi/libstub/x86: Work around LLVM ELF quirk build regression

When building the x86 EFI stub with Clang, the libstub Makefile rules
that manipulate the ELF object files may throw an error

efi/libstub/x86: Work around LLVM ELF quirk build regression

When building the x86 EFI stub with Clang, the libstub Makefile rules
that manipulate the ELF object files may throw an error like:

STUBCPY drivers/firmware/efi/libstub/efi-stub-helper.stub.o
strip: drivers/firmware/efi/libstub/efi-stub-helper.stub.o: Failed to find link section for section 10
objcopy: drivers/firmware/efi/libstub/efi-stub-helper.stub.o: Failed to find link section for section 10

This is the result of a LLVM feature [0] where symbol references are
stored in a LLVM specific .llvm_addrsig section in a non-transparent way,
causing generic ELF tools such as strip or objcopy to choke on them.

So force the compiler not to emit these sections, by passing the
appropriate command line option.

[0] https://sourceware.org/bugzilla/show_bug.cgi?id=23817

Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Sami Tolvanen <samitolvanen@google.com>
Reported-by: Arnd Bergmann <arnd@arndb.de>
Suggested-by: Fangrui Song <maskray@google.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

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efi/x86: Remove __efistub_global and add relocation check

Instead of using __efistub_global to force variables into the .data
section, leave them in the .bss but pull the EFI stub's .bss

efi/x86: Remove __efistub_global and add relocation check

Instead of using __efistub_global to force variables into the .data
section, leave them in the .bss but pull the EFI stub's .bss section
into .data in the linker script for the compressed kernel.

Add relocation checking for x86 as well to catch non-PC-relative
relocations that require runtime processing, since the EFI stub does not
do any runtime relocation processing.

This will catch, for example, data relocations created by static
initializers of pointers.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200416151227.3360778-3-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

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efi/arm: Remove __efistub_global annotation

Instead of using __efistub_global to force variables into the .data
section, leave them in the .bss but pull the EFI stub's .bss section
i

efi/arm: Remove __efistub_global annotation

Instead of using __efistub_global to force variables into the .data
section, leave them in the .bss but pull the EFI stub's .bss section
into .data in the linker script for the compressed kernel.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Link: https://lore.kernel.org/r/20200416151227.3360778-2-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

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efi/libstub: Move efi_relocate_kernel() into separate source file

Move efi_relocate_kernel() into a separate source file, so that it
only gets pulled into builds for architectures that u

efi/libstub: Move efi_relocate_kernel() into separate source file

Move efi_relocate_kernel() into a separate source file, so that it
only gets pulled into builds for architectures that use it. Since
efi_relocate_kernel() is the only user of efi_low_alloc(), let's
move that over as well.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

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efi/libstub: Add API function to allocate aligned memory

Break out the code to create an aligned page allocation from mem.c
and move it into a function efi_allocate_pages_aligned() in al

efi/libstub: Add API function to allocate aligned memory

Break out the code to create an aligned page allocation from mem.c
and move it into a function efi_allocate_pages_aligned() in alignedmem.c.
Update efi_allocate_pages() to invoke it unless the minimum alignment
equals the EFI page size (4 KB), in which case the ordinary page
allocator is sufficient. This way, efi_allocate_pages_aligned() will
only be pulled into the build if it is actually being used (which will
be on arm64 only in the immediate future)

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

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efi/libstub: Move arm-stub to a common file

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.

efi/libstub: Move arm-stub to a common file

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@wdc.com>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
Link: https://lore.kernel.org/r/20200415195422.19866-2-atish.patra@wdc.com
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

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Merge tag 'v5.7-rc1' into locking/kcsan, to resolve conflicts and refresh

Resolve these conflicts:

arch/x86/Kconfig
arch/x86/kernel/Makefile

Do a minor

Merge tag 'v5.7-rc1' into locking/kcsan, to resolve conflicts and refresh

Resolve these conflicts:

arch/x86/Kconfig
arch/x86/kernel/Makefile

Do a minor "evil merge" to move the KCSAN entry up a bit by a few lines
in the Kconfig to reduce the probability of future conflicts.

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

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Merge branch 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 boot updates from Ingo Molnar:
"Misc cleanups and small enhancements all around the m

Merge branch 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 boot updates from Ingo Molnar:
"Misc cleanups and small enhancements all around the map"

* 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/boot/compressed: Fix debug_puthex() parameter type
x86/setup: Fix static memory detection
x86/vmlinux: Drop unneeded linker script discard of .eh_frame
x86/*/Makefile: Use -fno-asynchronous-unwind-tables to suppress .eh_frame sections
x86/boot/compressed: Remove .eh_frame section from bzImage
x86/boot/compressed/64: Remove .bss/.pgtable from bzImage
x86/boot/compressed/64: Use 32-bit (zero-extended) MOV for z_output_len
x86/boot/compressed/64: Use LEA to initialize boot stack pointer

show more ...

Merge branch 'x86/kdump' into locking/kcsan, to resolve conflicts

Conflicts:
arch/x86/purgatory/Makefile

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

x86/*/Makefile: Use -fno-asynchronous-unwind-tables to suppress .eh_frame sections

While discussing a patch to discard .eh_frame from the compressed
vmlinux using the linker script, Fang

x86/*/Makefile: Use -fno-asynchronous-unwind-tables to suppress .eh_frame sections

While discussing a patch to discard .eh_frame from the compressed
vmlinux using the linker script, Fangrui Song pointed out [1] that these
sections shouldn't exist in the first place because arch/x86/Makefile
uses -fno-asynchronous-unwind-tables.

It turns out this is because the Makefiles used to build the compressed
kernel redefine KBUILD_CFLAGS, dropping this flag.

Add the flag to the Makefile for the compressed kernel, as well as the
EFI stub Makefile to fix this.

Also add the flag to boot/Makefile and realmode/rm/Makefile so that the
kernel's boot code (boot/setup.elf) and realmode trampoline
(realmode/rm/realmode.elf) won't be compiled with .eh_frame sections,
since their linker scripts also just discard them.

[1] https://lore.kernel.org/lkml/20200222185806.ywnqhfqmy67akfsa@google.com/

Suggested-by: Fangrui Song <maskray@google.com>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Nathan Chancellor <natechancellor@gmail.com>
Link: https://lkml.kernel.org/r/20200224232129.597160-2-nivedita@alum.mit.edu

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efi/libstub: Clean up command line parsing routine

We currently parse the command non-destructively, to avoid having to
allocate memory for a copy before passing it to the standard parsi

efi/libstub: Clean up command line parsing routine

We currently parse the command non-destructively, to avoid having to
allocate memory for a copy before passing it to the standard parsing
routines that are used by the core kernel, and which modify the input
to delineate the parsed tokens with NUL characters.

Instead, we call strstr() and strncmp() to go over the input multiple
times, and match prefixes rather than tokens, which implies that we
would match, e.g., 'nokaslrfoo' in the stub and disable KASLR, while
the kernel would disregard the option and run with KASLR enabled.

In order to avoid having to reason about whether and how this behavior
may be abused, let's clean up the parsing routines, and rebuild them
on top of the existing helpers.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

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efi/libstub: Move file I/O support code into separate file

Split off the file I/O support code into a separate source file so
it ends up in a separate object file in the static library,

efi/libstub: Move file I/O support code into separate file

Split off the file I/O support code into a separate source file so
it ends up in a separate object file in the static library, allowing
the linker to omit it if the routines are not used.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

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