linux-stable.git/drivers/firmware, branch v5.17.7 Linux kernel stable tree firmware: cs_dsp: Fix overrun of unterminated control name string 2022-04-27T12:40:57+00:00 Richard Fitzgerald rf@opensource.cirrus.com 2022-04-12T16:39:27+00:00 07ab8ba8c7ad887a49151b6058384766ba5e84d1 [ Upstream commit 5b933c7262c5b0ea11ea3c3b3ea81add04895954 ] For wmfw format v2 and later the coefficient name strings have a length field and are NOT null-terminated. Use kasprintf() to convert the unterminated string into a null-terminated string in an allocated buffer. The previous code handled this duplication incorrectly using kmemdup() and getting the length from a strlen() of the (unterminated) source string. This resulted in creating a string that continued up to the next byte in the firmware file that just happened to be 0x00. Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com> Fixes: f6bc909e7673 ("firmware: cs_dsp: add driver to support firmware loading on Cirrus Logic DSPs") Link: https://lore.kernel.org/r/20220412163927.1303470-1-rf@opensource.cirrus.com Signed-off-by: Mark Brown <broonie@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 5b933c7262c5b0ea11ea3c3b3ea81add04895954 ]

For wmfw format v2 and later the coefficient name strings have a length
field and are NOT null-terminated. Use kasprintf() to convert the
unterminated string into a null-terminated string in an allocated buffer.

The previous code handled this duplication incorrectly using kmemdup()
and getting the length from a strlen() of the (unterminated) source string.
This resulted in creating a string that continued up to the next byte in
the firmware file that just happened to be 0x00.

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
Fixes: f6bc909e7673 ("firmware: cs_dsp: add driver to support firmware loading on Cirrus Logic DSPs")
Link: https://lore.kernel.org/r/20220412163927.1303470-1-rf@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
firmware: arm_scmi: Fix sorting of retrieved clock rates 2022-04-20T07:36:12+00:00 Cristian Marussi cristian.marussi@arm.com 2022-03-18T09:28:13+00:00 fb8224e8c1efa36280e88bb83198760e187218ba [ Upstream commit 23274739a5b6166f74d8d9cb5243d7bf6b46aab9 ] During SCMI Clock protocol initialization, after having retrieved from the SCMI platform all the available discrete rates for a specific clock, the clock rates array is sorted, unfortunately using a pointer to its end as a base instead of its start, so that sorting does not work. Fix invocation of sort() passing as base a pointer to the start of the retrieved clock rates array. Link: https://lore.kernel.org/r/20220318092813.49283-1-cristian.marussi@arm.com Fixes: dccec73de91d ("firmware: arm_scmi: Keep the discrete clock rates sorted") Signed-off-by: Cristian Marussi <cristian.marussi@arm.com> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 23274739a5b6166f74d8d9cb5243d7bf6b46aab9 ]

During SCMI Clock protocol initialization, after having retrieved from the
SCMI platform all the available discrete rates for a specific clock, the
clock rates array is sorted, unfortunately using a pointer to its end as
a base instead of its start, so that sorting does not work.

Fix invocation of sort() passing as base a pointer to the start of the
retrieved clock rates array.

Link: https://lore.kernel.org/r/20220318092813.49283-1-cristian.marussi@arm.com
Fixes: dccec73de91d ("firmware: arm_scmi: Keep the discrete clock rates sorted")
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
firmware: arm_scmi: Remove clear channel call on the TX channel 2022-04-20T07:36:11+00:00 Cristian Marussi cristian.marussi@arm.com 2022-02-24T15:24:04+00:00 10bfc4747f1d06e501a830526a239c4265584166 [ Upstream commit 98f0d68f94ea21541e0050cc64fa108ade779839 ] On SCMI transports whose channels are based on a shared resource the TX channel area has to be acquired by the agent before placing the desired command into the channel and it will be then relinquished by the platform once the related reply has been made available into the channel. On an RX channel the logic is reversed with the platform acquiring the channel area and the agent reliquishing it once done by calling the scmi_clear_channel() helper. As a consequence, even in case of error, the agent must never try to clear a TX channel from its side: restrict the existing clear channel call on the the reply path only to delayed responses since they are indeed coming from the RX channel. Link: https://lore.kernel.org/r/20220224152404.12877-1-cristian.marussi@arm.com Fixes: e9b21c96181c ("firmware: arm_scmi: Make .clear_channel optional") Signed-off-by: Cristian Marussi <cristian.marussi@arm.com> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 98f0d68f94ea21541e0050cc64fa108ade779839 ]

On SCMI transports whose channels are based on a shared resource the TX
channel area has to be acquired by the agent before placing the desired
command into the channel and it will be then relinquished by the platform
once the related reply has been made available into the channel.
On an RX channel the logic is reversed with the platform acquiring the
channel area and the agent reliquishing it once done by calling the
scmi_clear_channel() helper.

As a consequence, even in case of error, the agent must never try to clear
a TX channel from its side: restrict the existing clear channel call on the
the reply path only to delayed responses since they are indeed coming from
the RX channel.

Link: https://lore.kernel.org/r/20220224152404.12877-1-cristian.marussi@arm.com
Fixes: e9b21c96181c ("firmware: arm_scmi: Make .clear_channel optional")
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
firmware: google: Properly state IOMEM dependency 2022-04-08T11:58:30+00:00 David Gow davidgow@google.com 2022-02-25T04:15:02+00:00 c5211e1740d1fccc92a9df4ecec33fd1c7262d2f [ Upstream commit 37fd83916da2e4cae03d350015c82a67b1b334c4 ] The Google Coreboot implementation requires IOMEM functions (memmremap, memunmap, devm_memremap), but does not specify this is its Kconfig. This results in build errors when HAS_IOMEM is not set, such as on some UML configurations: /usr/bin/ld: drivers/firmware/google/coreboot_table.o: in function `coreboot_table_probe': coreboot_table.c:(.text+0x311): undefined reference to `memremap' /usr/bin/ld: coreboot_table.c:(.text+0x34e): undefined reference to `memunmap' /usr/bin/ld: drivers/firmware/google/memconsole-coreboot.o: in function `memconsole_probe': memconsole-coreboot.c:(.text+0x12d): undefined reference to `memremap' /usr/bin/ld: memconsole-coreboot.c:(.text+0x17e): undefined reference to `devm_memremap' /usr/bin/ld: memconsole-coreboot.c:(.text+0x191): undefined reference to `memunmap' /usr/bin/ld: drivers/firmware/google/vpd.o: in function `vpd_section_destroy.isra.0': vpd.c:(.text+0x300): undefined reference to `memunmap' /usr/bin/ld: drivers/firmware/google/vpd.o: in function `vpd_section_init': vpd.c:(.text+0x382): undefined reference to `memremap' /usr/bin/ld: vpd.c:(.text+0x459): undefined reference to `memunmap' /usr/bin/ld: drivers/firmware/google/vpd.o: in function `vpd_probe': vpd.c:(.text+0x59d): undefined reference to `memremap' /usr/bin/ld: vpd.c:(.text+0x5d3): undefined reference to `memunmap' collect2: error: ld returned 1 exit status Fixes: a28aad66da8b ("firmware: coreboot: Collapse platform drivers into bus core") Acked-By: anton ivanov <anton.ivanov@cambridgegreys.com> Acked-By: Julius Werner <jwerner@chromium.org> Signed-off-by: David Gow <davidgow@google.com> Link: https://lore.kernel.org/r/20220225041502.1901806-1-davidgow@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 37fd83916da2e4cae03d350015c82a67b1b334c4 ]

The Google Coreboot implementation requires IOMEM functions
(memmremap, memunmap, devm_memremap), but does not specify this is its
Kconfig. This results in build errors when HAS_IOMEM is not set, such as
on some UML configurations:

/usr/bin/ld: drivers/firmware/google/coreboot_table.o: in function `coreboot_table_probe':
coreboot_table.c:(.text+0x311): undefined reference to `memremap'
/usr/bin/ld: coreboot_table.c:(.text+0x34e): undefined reference to `memunmap'
/usr/bin/ld: drivers/firmware/google/memconsole-coreboot.o: in function `memconsole_probe':
memconsole-coreboot.c:(.text+0x12d): undefined reference to `memremap'
/usr/bin/ld: memconsole-coreboot.c:(.text+0x17e): undefined reference to `devm_memremap'
/usr/bin/ld: memconsole-coreboot.c:(.text+0x191): undefined reference to `memunmap'
/usr/bin/ld: drivers/firmware/google/vpd.o: in function `vpd_section_destroy.isra.0':
vpd.c:(.text+0x300): undefined reference to `memunmap'
/usr/bin/ld: drivers/firmware/google/vpd.o: in function `vpd_section_init':
vpd.c:(.text+0x382): undefined reference to `memremap'
/usr/bin/ld: vpd.c:(.text+0x459): undefined reference to `memunmap'
/usr/bin/ld: drivers/firmware/google/vpd.o: in function `vpd_probe':
vpd.c:(.text+0x59d): undefined reference to `memremap'
/usr/bin/ld: vpd.c:(.text+0x5d3): undefined reference to `memunmap'
collect2: error: ld returned 1 exit status

Fixes: a28aad66da8b ("firmware: coreboot: Collapse platform drivers into bus core")
Acked-By: anton ivanov <anton.ivanov@cambridgegreys.com>
Acked-By: Julius Werner <jwerner@chromium.org>
Signed-off-by: David Gow <davidgow@google.com>
Link: https://lore.kernel.org/r/20220225041502.1901806-1-davidgow@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
firmware: qcom: scm: Remove reassignment to desc following initializer 2022-04-08T11:57:44+00:00 Marijn Suijten marijn.suijten@somainline.org 2021-12-08T08:34:21+00:00 88d707f40576e5aa87d765d193ad4f64c7a2a8e0 [ Upstream commit 7823e5aa5d1dd9ed5849923c165eb8f29ad23c54 ] Member assignments to qcom_scm_desc were moved into struct initializers in 57d3b816718c ("firmware: qcom_scm: Remove thin wrappers") including the case in qcom_scm_iommu_secure_ptbl_init, except that the - now duplicate - assignment to desc was left in place. While not harmful, remove this unnecessary extra reassignment. Fixes: 57d3b816718c ("firmware: qcom_scm: Remove thin wrappers") Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org> Reviewed-by: Alex Elder <elder@linaro.org> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org> Link: https://lore.kernel.org/r/20211208083423.22037-2-marijn.suijten@somainline.org Signed-off-by: Sasha Levin <sashal@kernel.org> 
[ Upstream commit 7823e5aa5d1dd9ed5849923c165eb8f29ad23c54 ]

Member assignments to qcom_scm_desc were moved into struct initializers
in 57d3b816718c ("firmware: qcom_scm: Remove thin wrappers") including
the case in qcom_scm_iommu_secure_ptbl_init, except that the - now
duplicate - assignment to desc was left in place. While not harmful,
remove this unnecessary extra reassignment.

Fixes: 57d3b816718c ("firmware: qcom_scm: Remove thin wrappers")
Signed-off-by: Marijn Suijten <marijn.suijten@somainline.org>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@somainline.org>
Reviewed-by: Alex Elder <elder@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Link: https://lore.kernel.org/r/20211208083423.22037-2-marijn.suijten@somainline.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
pstore: Don't use semaphores in always-atomic-context code 2022-04-08T11:57:27+00:00 Jann Horn jannh@google.com 2022-03-14T18:59:53+00:00 f6292deb88e12187d47d4dd3c69934377db49d79 commit 8126b1c73108bc691f5643df19071a59a69d0bc6 upstream. pstore_dump() is *always* invoked in atomic context (nowadays in an RCU read-side critical section, before that under a spinlock). It doesn't make sense to try to use semaphores here. This is mostly a revert of commit ea84b580b955 ("pstore: Convert buf_lock to semaphore"), except that two parts aren't restored back exactly as they were: - keep the lock initialization in pstore_register - in efi_pstore_write(), always set the "block" flag to false - omit "is_locked", that was unnecessary since commit 959217c84c27 ("pstore: Actually give up during locking failure") - fix the bailout message The actual problem that the buggy commit was trying to address may have been that the use of preemptible() in efi_pstore_write() was wrong - it only looks at preempt_count() and the state of IRQs, but __rcu_read_lock() doesn't touch either of those under CONFIG_PREEMPT_RCU. (Sidenote: CONFIG_PREEMPT_RCU means that the scheduler can preempt tasks in RCU read-side critical sections, but you're not allowed to actively block/reschedule.) Lockdep probably never caught the problem because it's very rare that you actually hit the contended case, so lockdep always just sees the down_trylock(), not the down_interruptible(), and so it can't tell that there's a problem. Fixes: ea84b580b955 ("pstore: Convert buf_lock to semaphore") Cc: stable@vger.kernel.org Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Jann Horn <jannh@google.com> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20220314185953.2068993-1-jannh@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 8126b1c73108bc691f5643df19071a59a69d0bc6 upstream.

pstore_dump() is *always* invoked in atomic context (nowadays in an RCU
read-side critical section, before that under a spinlock).
It doesn't make sense to try to use semaphores here.

This is mostly a revert of commit ea84b580b955 ("pstore: Convert buf_lock
to semaphore"), except that two parts aren't restored back exactly as they
were:

 - keep the lock initialization in pstore_register
 - in efi_pstore_write(), always set the "block" flag to false
 - omit "is_locked", that was unnecessary since
   commit 959217c84c27 ("pstore: Actually give up during locking failure")
 - fix the bailout message

The actual problem that the buggy commit was trying to address may have
been that the use of preemptible() in efi_pstore_write() was wrong - it
only looks at preempt_count() and the state of IRQs, but __rcu_read_lock()
doesn't touch either of those under CONFIG_PREEMPT_RCU.
(Sidenote: CONFIG_PREEMPT_RCU means that the scheduler can preempt tasks in
RCU read-side critical sections, but you're not allowed to actively
block/reschedule.)

Lockdep probably never caught the problem because it's very rare that you
actually hit the contended case, so lockdep always just sees the
down_trylock(), not the down_interruptible(), and so it can't tell that
there's a problem.

Fixes: ea84b580b955 ("pstore: Convert buf_lock to semaphore")
Cc: stable@vger.kernel.org
Acked-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220314185953.2068993-1-jannh@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
firmware: sysfb: fix platform-device leak in error path 2022-04-08T11:57:17+00:00 Johan Hovold johan@kernel.org 2022-03-03T18:05:19+00:00 fed4df558b8cdb6f3beea38a7c977f118f082b0d commit 202c08914ba50dd324e42d5ad99535a89f242560 upstream. Make sure to free the platform device also in the unlikely event that registration fails. Fixes: 0589e8889dce ("drivers/firmware: Add missing platform_device_put() in sysfb_create_simplefb") Fixes: 8633ef82f101 ("drivers/firmware: consolidate EFI framebuffer setup for all arches") Cc: stable@vger.kernel.org # 5.14 Cc: Miaoqian Lin <linmq006@gmail.com> Cc: Javier Martinez Canillas <javierm@redhat.com> Signed-off-by: Johan Hovold <johan@kernel.org> Link: https://lore.kernel.org/r/20220303180519.3117-1-johan@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit 202c08914ba50dd324e42d5ad99535a89f242560 upstream.

Make sure to free the platform device also in the unlikely event that
registration fails.

Fixes: 0589e8889dce ("drivers/firmware: Add missing platform_device_put() in sysfb_create_simplefb")
Fixes: 8633ef82f101 ("drivers/firmware: consolidate EFI framebuffer setup for all arches")
Cc: stable@vger.kernel.org      # 5.14
Cc: Miaoqian Lin <linmq006@gmail.com>
Cc: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Link: https://lore.kernel.org/r/20220303180519.3117-1-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
firmware: stratix10-svc: add missing callback parameter on RSU 2022-04-08T11:57:17+00:00 Ang Tien Sung tien.sung.ang@intel.com 2022-02-23T14:41:46+00:00 f9dd29844bb2a5097929773bbd33949c8cbe44df commit b850b7a8b369322adf699ef48ceff4d902525c8c upstream. Fix a bug whereby, the return response of parameter a1 from an SMC call is not properly set to the callback data during an INTEL_SIP_SMC_RSU_ERROR command. Link: https://lore.kernel.org/lkml/20220216081513.28319-1-tien.sung.ang@intel.com Fixes: 6b50d882d38d ("firmware: add remote status update client support") Cc: stable@vger.kernel.org Signed-off-by: Ang Tien Sung <tien.sung.ang@intel.com> Signed-off-by: Dinh Nguyen <dinguyen@kernel.org> Link: https://lore.kernel.org/r/20220223144146.399263-1-dinguyen@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> 
commit b850b7a8b369322adf699ef48ceff4d902525c8c upstream.

Fix a bug whereby, the return response of parameter a1 from an
SMC call is not properly set to the callback data during an
INTEL_SIP_SMC_RSU_ERROR command.

Link: https://lore.kernel.org/lkml/20220216081513.28319-1-tien.sung.ang@intel.com
Fixes: 6b50d882d38d ("firmware: add remote status update client support")
Cc: stable@vger.kernel.org
Signed-off-by: Ang Tien Sung <tien.sung.ang@intel.com>
Signed-off-by: Dinh Nguyen <dinguyen@kernel.org>
Link: https://lore.kernel.org/r/20220223144146.399263-1-dinguyen@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Merge tag 'efi-urgent-for-v5.17-3' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi 2022-03-16T18:57:46+00:00 Linus Torvalds torvalds@linux-foundation.org 2022-03-16T18:57:46+00:00 a46310bfae94cfadf3d28a4d97b71e3e4dcc954c Pull EFI fix from Ard Biesheuvel: "Avoid spurious warnings about unknown boot parameters" * tag 'efi-urgent-for-v5.17-3' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi: efi: fix return value of __setup handlers 
Pull EFI fix from Ard Biesheuvel:
 "Avoid spurious warnings about unknown boot parameters"

* tag 'efi-urgent-for-v5.17-3' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi:
  efi: fix return value of __setup handlers
efi: fix return value of __setup handlers 2022-03-01T08:02:21+00:00 Randy Dunlap rdunlap@infradead.org 2022-03-01T04:18:51+00:00 9feaf8b387ee0ece9c1d7add308776b502a35d0c When "dump_apple_properties" is used on the kernel boot command line, it causes an Unknown parameter message and the string is added to init's argument strings: Unknown kernel command line parameters "dump_apple_properties BOOT_IMAGE=/boot/bzImage-517rc6 efivar_ssdt=newcpu_ssdt", will be passed to user space. Run /sbin/init as init process with arguments: /sbin/init dump_apple_properties with environment: HOME=/ TERM=linux BOOT_IMAGE=/boot/bzImage-517rc6 efivar_ssdt=newcpu_ssdt Similarly when "efivar_ssdt=somestring" is used, it is added to the Unknown parameter message and to init's environment strings, polluting them (see examples above). Change the return value of the __setup functions to 1 to indicate that the __setup options have been handled. Fixes: 58c5475aba67 ("x86/efi: Retrieve and assign Apple device properties") Fixes: 475fb4e8b2f4 ("efi / ACPI: load SSTDs from EFI variables") Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Reported-by: Igor Zhbanov <i.zhbanov@omprussia.ru> Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru Cc: Ard Biesheuvel <ardb@kernel.org> Cc: linux-efi@vger.kernel.org Cc: Lukas Wunner <lukas@wunner.de> Cc: Octavian Purdila <octavian.purdila@intel.com> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Matt Fleming <matt@codeblueprint.co.uk> Link: https://lore.kernel.org/r/20220301041851.12459-1-rdunlap@infradead.org Signed-off-by: Ard Biesheuvel <ardb@kernel.org> 
When "dump_apple_properties" is used on the kernel boot command line,
it causes an Unknown parameter message and the string is added to init's
argument strings:

  Unknown kernel command line parameters "dump_apple_properties
    BOOT_IMAGE=/boot/bzImage-517rc6 efivar_ssdt=newcpu_ssdt", will be
    passed to user space.

 Run /sbin/init as init process
   with arguments:
     /sbin/init
     dump_apple_properties
   with environment:
     HOME=/
     TERM=linux
     BOOT_IMAGE=/boot/bzImage-517rc6
     efivar_ssdt=newcpu_ssdt

Similarly when "efivar_ssdt=somestring" is used, it is added to the
Unknown parameter message and to init's environment strings, polluting
them (see examples above).

Change the return value of the __setup functions to 1 to indicate
that the __setup options have been handled.

Fixes: 58c5475aba67 ("x86/efi: Retrieve and assign Apple device properties")
Fixes: 475fb4e8b2f4 ("efi / ACPI: load SSTDs from EFI variables")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: Igor Zhbanov <i.zhbanov@omprussia.ru>
Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@omprussia.ru
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: linux-efi@vger.kernel.org
Cc: Lukas Wunner <lukas@wunner.de>
Cc: Octavian Purdila <octavian.purdila@intel.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Link: https://lore.kernel.org/r/20220301041851.12459-1-rdunlap@infradead.org
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>