Commit Graph

2107 Commits

Author SHA1 Message Date
Linus Torvalds 17baa44286 Merge tag 'efi-urgent-2020-07-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip into master
Pull EFI fixes from Ingo Molnar:
 "Various EFI fixes:

   - Fix the layering violation in the use of the EFI runtime services
     availability mask in users of the 'efivars' abstraction

   - Revert build fix for GCC v4.8 which is no longer supported

   - Clean up some x86 EFI stub details, some of which are borderline
     bugs that copy around garbage into padding fields - let's fix these
     out of caution.

   - Fix build issues while working on RISC-V support

   - Avoid --whole-archive when linking the stub on arm64"

* tag 'efi-urgent-2020-07-25' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  efi: Revert "efi/x86: Fix build with gcc 4"
  efi/efivars: Expose RT service availability via efivars abstraction
  efi/libstub: Move the function prototypes to header file
  efi/libstub: Fix gcc error around __umoddi3 for 32 bit builds
  efi/libstub/arm64: link stub lib.a conditionally
  efi/x86: Only copy upto the end of setup_header
  efi/x86: Remove unused variables
2020-07-25 13:18:42 -07:00
Linus Torvalds a570f41989 Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux into master
Pull arm64 fixes from Will Deacon:
 "A batch of arm64 fixes.

  Although the diffstat is a bit larger than we'd usually have at this
  stage, a decent amount of it is the addition of comments describing
  our syscall tracing behaviour, and also a sweep across all the modular
  arm64 PMU drivers to make them rebust against unloading and unbinding.

  There are a couple of minor things kicking around at the moment (CPU
  errata and module PLTs for very large modules), but I'm not expecting
  any significant changes now for us in 5.8.

   - Fix kernel text addresses for relocatable images booting using EFI
     and with KASLR disabled so that they match the vmlinux ELF binary.

   - Fix unloading and unbinding of PMU driver modules.

   - Fix generic mmiowb() when writeX() is called from preemptible
     context (reported by the riscv folks).

   - Fix ptrace hardware single-step interactions with signal handlers,
     system calls and reverse debugging.

   - Fix reporting of 64-bit x0 register for 32-bit tasks via
     'perf_regs'.

   - Add comments describing syscall entry/exit tracing ABI"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  drivers/perf: Prevent forced unbinding of PMU drivers
  asm-generic/mmiowb: Allow mmiowb_set_pending() when preemptible()
  arm64: Use test_tsk_thread_flag() for checking TIF_SINGLESTEP
  arm64: ptrace: Use NO_SYSCALL instead of -1 in syscall_trace_enter()
  arm64: syscall: Expand the comment about ptrace and syscall(-1)
  arm64: ptrace: Add a comment describing our syscall entry/exit trap ABI
  arm64: compat: Ensure upper 32 bits of x0 are zero on syscall return
  arm64: ptrace: Override SPSR.SS when single-stepping is enabled
  arm64: ptrace: Consistently use pseudo-singlestep exceptions
  drivers/perf: Fix kernel panic when rmmod PMU modules during perf sampling
  efi/libstub/arm64: Retain 2MB kernel Image alignment if !KASLR
2020-07-17 15:27:52 -07:00
Will Deacon 7c116db24d efi/libstub/arm64: Retain 2MB kernel Image alignment if !KASLR
Since commit 82046702e2 ("efi/libstub/arm64: Replace 'preferred' offset
with alignment check"), loading a relocatable arm64 kernel at a physical
address which is not 2MB aligned and subsequently booting with EFI will
leave the Image in-place, relying on the kernel to relocate itself early
during boot. In conjunction with commit dd4bc60765 ("arm64: warn on
incorrect placement of the kernel by the bootloader"), which enables
CONFIG_RELOCATABLE by default, this effectively means that entering an
arm64 kernel loaded at an alignment smaller than 2MB with EFI (e.g. using
QEMU) will result in silent relocation at runtime.

Unfortunately, this has a subtle but confusing affect for developers
trying to inspect the PC value during a crash and comparing it to the
symbol addresses in vmlinux using tools such as 'nm' or 'addr2line';
all text addresses will be displaced by a sub-2MB offset, resulting in
the wrong symbol being identified in many cases. Passing "nokaslr" on
the command line or disabling "CONFIG_RANDOMIZE_BASE" does not help,
since the EFI stub only copies the kernel Image to a 2MB boundary if it
is not relocatable.

Adjust the EFI stub for arm64 so that the minimum Image alignment is 2MB
unless KASLR is in use.

Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: David Brazdil <dbrazdil@google.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Will Deacon <will@kernel.org>
2020-07-13 14:08:07 +01:00
Linus Torvalds f4c8824cbc Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux
Pull arm64 fixes from Will Deacon:
 "An unfortunately large collection of arm64 fixes for -rc5.

  Some of this is absolutely trivial, but the alternatives, vDSO and CPU
  errata workaround fixes are significant. At least people are finding
  and fixing these things, I suppose.

   - Fix workaround for CPU erratum #1418040 to disable the compat vDSO

   - Fix Oops when single-stepping with KGDB

   - Fix memory attributes for hypervisor device mappings at EL2

   - Fix memory leak in PSCI and remove useless variable assignment

   - Fix up some comments and asm labels in our entry code

   - Fix broken register table formatting in our generated html docs

   - Fix missing NULL sentinel in CPU errata workaround list

   - Fix patching of branches in alternative instruction sections"

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm64/alternatives: don't patch up internal branches
  arm64: Add missing sentinel to erratum_1463225
  arm64: Documentation: Fix broken table in generated HTML
  arm64: kgdb: Fix single-step exception handling oops
  arm64: entry: Tidy up block comments and label numbers
  arm64: Rework ARM_ERRATUM_1414080 handling
  arm64: arch_timer: Disable the compat vdso for cores affected by ARM64_WORKAROUND_1418040
  arm64: arch_timer: Allow an workaround descriptor to disable compat vdso
  arm64: Introduce a way to disable the 32bit vdso
  arm64: entry: Fix the typo in the comment of el1_dbg()
  drivers/firmware/psci: Assign @err directly in hotplug_tests()
  drivers/firmware/psci: Fix memory leakage in alloc_init_cpu_groups()
  KVM: arm64: Fix definition of PAGE_HYP_DEVICE
2020-07-10 08:42:17 -07:00
Ard Biesheuvel 769e0fe117 efi: Revert "efi/x86: Fix build with gcc 4"
This reverts commit 5435f73d5c, 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>
2020-07-09 10:14:29 +03:00
Ard Biesheuvel f88814cc25 efi/efivars: Expose RT service availability via efivars abstraction
Commit

  bf67fad19e ("efi: Use more granular check for availability for variable services")

introduced a check into the efivarfs, efi-pstore and other drivers that
aborts loading of the module if not all three variable runtime services
(GetVariable, SetVariable and GetNextVariable) are supported. However, this
results in efivarfs being unavailable entirely if only SetVariable support
is missing, which is only needed if you want to make any modifications.
Also, efi-pstore and the sysfs EFI variable interface could be backed by
another implementation of the 'efivars' abstraction, in which case it is
completely irrelevant which services are supported by the EFI firmware.

So make the generic 'efivars' abstraction dependent on the availibility of
the GetVariable and GetNextVariable EFI runtime services, and add a helper
'efivar_supports_writes()' to find out whether the currently active efivars
abstraction supports writes (and wire it up to the availability of
SetVariable for the generic one).

Then, use the efivar_supports_writes() helper to decide whether to permit
efivarfs to be mounted read-write, and whether to enable efi-pstore or the
sysfs EFI variable interface altogether.

Fixes: bf67fad19e ("efi: Use more granular check for availability for variable services")
Reported-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Tested-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-07-09 10:14:29 +03:00
Atish Patra 3230d95cea efi/libstub: Move the function prototypes to header file
The prototype of the functions handle_kernel_image & efi_enter_kernel
are defined in efi-stub.c which may result in a compiler warnings if
-Wmissing-prototypes is set in gcc compiler.

Move the prototype to efistub.h to make the compiler happy.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Link: https://lore.kernel.org/r/20200706172609.25965-2-atish.patra@wdc.com
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-07-09 09:45:09 +03:00
Atish Patra 950accbabd efi/libstub: Fix gcc error around __umoddi3 for 32 bit builds
32bit gcc doesn't support modulo operation on 64 bit data. It results in
a __umoddi3 error while building EFI for 32 bit.

Use bitwise operations instead of modulo operations to fix the issue.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Link: https://lore.kernel.org/r/20200625234516.31406-2-atish.patra@wdc.com
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-07-09 09:45:09 +03:00
Gavin Shan 132330f804 drivers/firmware/psci: Assign @err directly in hotplug_tests()
The return value of down_and_up_cpus() can be assigned to @err directly.
With that, the useless assignment to @err with zero can be dropped.

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Link: https://lore.kernel.org/r/20200630075943.203954-1-gshan@redhat.com
Signed-off-by: Will Deacon <will@kernel.org>
2020-07-08 21:41:24 +01:00
Gavin Shan c377e67c62 drivers/firmware/psci: Fix memory leakage in alloc_init_cpu_groups()
The CPU mask (@tmp) should be released on failing to allocate
@cpu_groups or any of its elements. Otherwise, it leads to memory
leakage because the CPU mask variable is dynamically allocated
when CONFIG_CPUMASK_OFFSTACK is enabled.

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Link: https://lore.kernel.org/r/20200630075227.199624-1-gshan@redhat.com
Signed-off-by: Will Deacon <will@kernel.org>
2020-07-08 21:40:33 +01:00
Linus Torvalds e44b59cd75 Merge tag 'arm-fixes-5.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc
Pull ARM SoC fixes from Arnd Bergmann:
 "Here are a couple of bug fixes, mostly for devicetree files

  NXP i.MX:
   - Use correct voltage on some i.MX8M board device trees to avoid
     hardware damage
   - Code fixes for a compiler warning and incorrect reference counting,
     both harmless.
   - Fix the i.MX8M SoC driver to correctly identify imx8mp
   - Fix watchdog configuration in imx6ul-kontron device tree.

  Broadcom:
   - A small regression fix for the Raspberry-Pi firmware driver
   - A Kconfig change to use the correct timer driver on Northstar
   - A DT fix for the Luxul XWC-2000 machine
   - Two more DT fixes for NSP SoCs

  STmicroelectronics STI
   - Revert one broken patch for L2 cache configuration

  ARM Versatile Express:
   - Fix a regression by reverting a broken DT cleanup

  TEE drivers:
   - MAINTAINERS: change tee mailing list"

* tag 'arm-fixes-5.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc:
  Revert "ARM: sti: Implement dummy L2 cache's write_sec"
  soc: imx8m: fix build warning
  ARM: imx6: add missing put_device() call in imx6q_suspend_init()
  ARM: imx5: add missing put_device() call in imx_suspend_alloc_ocram()
  soc: imx8m: Correct i.MX8MP UID fuse offset
  ARM: dts: imx6ul-kontron: Change WDOG_ANY signal from push-pull to open-drain
  ARM: dts: imx6ul-kontron: Move watchdog from Kontron i.MX6UL/ULL board to SoM
  arm64: dts: imx8mm-beacon: Fix voltages on LDO1 and LDO2
  arm64: dts: imx8mn-ddr4-evk: correct ldo1/ldo2 voltage range
  arm64: dts: imx8mm-evk: correct ldo1/ldo2 voltage range
  ARM: dts: NSP: Correct FA2 mailbox node
  ARM: bcm2835: Fix integer overflow in rpi_firmware_print_firmware_revision()
  MAINTAINERS: change tee mailing list
  ARM: dts: NSP: Disable PL330 by default, add dma-coherent property
  ARM: bcm: Select ARM_TIMER_SP804 for ARCH_BCM_NSP
  ARM: dts: BCM5301X: Add missing memory "device_type" for Luxul XWC-2000
  arm: dts: vexpress: Move mcc node back into motherboard node
2020-06-28 14:55:18 -07:00
Linus Torvalds bc53f67d24 Merge tag 'efi-urgent-2020-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull EFI fixes from Ingo Molnar:

 - Fix build regression on v4.8 and older

 - Robustness fix for TPM log parsing code

 - kobject refcount fix for the ESRT parsing code

 - Two efivarfs fixes to make it behave more like an ordinary file
   system

 - Style fixup for zero length arrays

 - Fix a regression in path separator handling in the initrd loader

 - Fix a missing prototype warning

 - Add some kerneldoc headers for newly introduced stub routines

 - Allow support for SSDT overrides via EFI variables to be disabled

 - Report CPU mode and MMU state upon entry for 32-bit ARM

 - Use the correct stack pointer alignment when entering from mixed mode

* tag 'efi-urgent-2020-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  efi/libstub: arm: Print CPU boot mode and MMU state at boot
  efi/libstub: arm: Omit arch specific config table matching array on arm64
  efi/x86: Setup stack correctly for efi_pe_entry
  efi: Make it possible to disable efivar_ssdt entirely
  efi/libstub: Descriptions for stub helper functions
  efi/libstub: Fix path separator regression
  efi/libstub: Fix missing-prototype warning for skip_spaces()
  efi: Replace zero-length array and use struct_size() helper
  efivarfs: Don't return -EINTR when rate-limiting reads
  efivarfs: Update inode modification time for successful writes
  efi/esrt: Fix reference count leak in esre_create_sysfs_entry.
  efi/tpm: Verify event log header before parsing
  efi/x86: Fix build with gcc 4
2020-06-28 11:42:16 -07:00
Arnd Bergmann 2596ce4b4d Merge tag 'arm-soc/for-5.8/drivers-fixes' of https://github.com/Broadcom/stblinux into arm/fixes
This pull request contains Broadcom ARM/ARM64/MIPS SoCs drivers fixes
for 5.8, please pull the following:

- Andy provides a fix for the Raspberry Pi firmware driver to print the
  correct time upon boot. This is a fallout from a converstion to use
  the ptT format

* tag 'arm-soc/for-5.8/drivers-fixes' of https://github.com/Broadcom/stblinux:
  ARM: bcm2835: Fix integer overflow in rpi_firmware_print_firmware_revision()

Link: https://lore.kernel.org/r/20200619202250.19029-2-f.fainelli@gmail.com
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2020-06-28 14:48:06 +02:00
Arvind Sankar 59476f80d8 efi/x86: Only copy upto the end of setup_header
When copying the setup_header into the boot_params buffer, only the data
that is actually part of the setup_header should be copied.

efi_pe_entry() currently copies the entire second sector, which
initializes some of the fields in boot_params beyond the setup_header
with garbage (i.e. part of the real-mode boot code gets copied into
those fields).

This does not cause any issues currently because the fields that are
overwritten are padding, BIOS EDD information that won't get used, and
the E820 table which will get properly filled in later.

Fix this to only copy data that is actually part of the setup_header
structure.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-06-25 18:09:48 +02:00
Arvind Sankar 0bda49f30c efi/x86: Remove unused variables
Commit

  987053a300 ("efi/x86: Move command-line initrd loading to efi_main")

made the ramdisk_addr/ramdisk_size variables in efi_pe_entry unused, but
neglected to delete them.

Delete these unused variables.

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-06-25 18:06:10 +02:00
Ard Biesheuvel 2a55280a36 efi/libstub: arm: Print CPU boot mode and MMU state at boot
On 32-bit ARM, we may boot at HYP mode, or with the MMU and caches off
(or both), even though the EFI spec does not actually support this.
While booting at HYP mode is something we might tolerate, fiddling
with the caches is a more serious issue, as disabling the caches is
tricky to do safely from C code, and running without the Dcache makes
it impossible to support unaligned memory accesses, which is another
explicit requirement imposed by the EFI spec.

So take note of the CPU mode and MMU state in the EFI stub diagnostic
output so that we can easily diagnose any issues that may arise from
this. E.g.,

  EFI stub: Entering in SVC mode with MMU enabled

Also, capture the CPSR and SCTLR system register values at EFI stub
entry, and after ExitBootServices() returns, and check whether the
MMU and Dcache were disabled at any point. If this is the case, a
diagnostic message like the following will be emitted:

  efi: [Firmware Bug]: EFI stub was entered with MMU and Dcache disabled, please fix your firmware!
  efi: CPSR at EFI stub entry        : 0x600001d3
  efi: SCTLR at EFI stub entry       : 0x00c51838
  efi: CPSR after ExitBootServices() : 0x600001d3
  efi: SCTLR after ExitBootServices(): 0x00c50838

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Leif Lindholm <leif@nuviainc.com>
2020-06-17 15:29:11 +02:00
Ard Biesheuvel 62956be8f9 efi/libstub: arm: Omit arch specific config table matching array on arm64
On arm64, the EFI stub is built into the kernel proper, and so the stub
can refer to its symbols directly. Therefore, the practice of using EFI
configuration tables to pass information between them is never needed,
so we can omit any code consuming such tables when building for arm64.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Leif Lindholm <leif@nuviainc.com>
2020-06-17 15:29:11 +02:00
Andy Shevchenko da785a8778 ARM: bcm2835: Fix integer overflow in rpi_firmware_print_firmware_revision()
time64_t is 64-bit width type, we are not supposed to supply lesser ones
as in the case of rpi_firmware_print_firmware_revision() after the commit
4a60f58ee0 ("ARM: bcm2835: Switch to use %ptT"). Use temporary variable
of time64_t type to correctly handle lesser types.

Fixes: 4a60f58ee0 ("ARM: bcm2835: Switch to use %ptT")
Reported-by: Stefan Wahren <wahrenst@gmx.net>
Reported-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Revieved-by: Petr Mladek <pmladek@suse.com>
Tested-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Link: https://lore.kernel.org/r/20200616163139.4229-1-andriy.shevchenko@linux.intel.com
2020-06-17 12:51:45 +02:00
Peter Jones 435d1a4715 efi: Make it possible to disable efivar_ssdt entirely
In most cases, such as CONFIG_ACPI_CUSTOM_DSDT and
CONFIG_ACPI_TABLE_UPGRADE, boot-time modifications to firmware tables
are tied to specific Kconfig options.  Currently this is not the case
for modifying the ACPI SSDT via the efivar_ssdt kernel command line
option and associated EFI variable.

This patch adds CONFIG_EFI_CUSTOM_SSDT_OVERLAYS, which defaults
disabled, in order to allow enabling or disabling that feature during
the build.

Cc: <stable@vger.kernel.org>
Signed-off-by: Peter Jones <pjones@redhat.com>
Link: https://lore.kernel.org/r/20200615202408.2242614-1-pjones@redhat.com
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-06-16 11:01:07 +02:00
Heinrich Schuchardt 8c0a839c2b efi/libstub: Descriptions for stub helper functions
Provide missing descriptions for EFI stub helper functions.
Adjust formatting of existing descriptions to kernel style.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Link: https://lore.kernel.org/r/20200615234231.21059-1-xypron.glpk@gmx.de
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
2020-06-16 11:01:07 +02:00
Gustavo A. R. Silva b912f89c94 firmware: pcdp: Replace zero-length array with flexible-array
There is a regular need in the kernel to provide a way to declare having a
dynamically sized set of trailing elements in a structure. Kernel code should
always use “flexible array members”[1] for these cases. The older style of
one-element or zero-length arrays should no longer be used[2].

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://github.com/KSPP/linux/issues/21

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2020-06-15 23:08:32 -05:00
Gustavo A. R. Silva 8192e60c6a ibft: Replace zero-length array with flexible-array
There is a regular need in the kernel to provide a way to declare having a
dynamically sized set of trailing elements in a structure. Kernel code should
always use “flexible array members”[1] for these cases. The older style of
one-element or zero-length arrays should no longer be used[2].

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://github.com/KSPP/linux/issues/21

Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2020-06-15 23:08:31 -05:00
Gustavo A. R. Silva aa125f313d firmware: google: vpd: Replace zero-length array with flexible-array member
There is a regular need in the kernel to provide a way to declare having a
dynamically sized set of trailing elements in a structure. Kernel code should
always use “flexible array members”[1] for these cases. The older style of
one-element or zero-length arrays should no longer be used[2].

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://github.com/KSPP/linux/issues/21

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
2020-06-15 23:08:21 -05:00
Gustavo A. R. Silva ea9ee99767 firmware: google: memconsole: Replace zero-length array with flexible-array member
There is a regular need in the kernel to provide a way to declare having a
dynamically sized set of trailing elements in a structure. Kernel code should
always use “flexible array members”[1] for these cases. The older style of
one-element or zero-length arrays should no longer be used[2].

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://github.com/KSPP/linux/issues/21

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
2020-06-15 23:08:16 -05:00
Gustavo A. R. Silva 8e849a4127 firmware: dmi-sysfs: Replace zero-length array with flexible-array member
There is a regular need in the kernel to provide a way to declare having a
dynamically sized set of trailing elements in a structure. Kernel code should
always use “flexible array members”[1] for these cases. The older style of
one-element or zero-length arrays should no longer be used[2].

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://github.com/KSPP/linux/issues/21

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
2020-06-15 23:08:04 -05:00