This patch attaches the colorspace connector property to the
hdmi connector. Based on colorspace change, modeset will be
triggered to switch to new colorspace.
Based on colorspace property value create an infoframe
with appropriate colorspace. This can be used to send an
infoframe packet with proper colorspace value set which
will help to enable wider color gamut like BT2020 on sink.
This patch attaches and enables HDMI colorspace, DP will be
taken care separately.
v2: Merged the changes of creating infoframe as well to this
patch as per Maarten's suggestion.
v3: Addressed review comments from Shashank. Separated HDMI
and DP colorspaces as suggested by Ville and Maarten.
v4: Addressed Chris and Ville's review comments, and created a
common colorspace property for DP and HDMI, filtered the list
based on the colorspaces supported by the respective protocol
standard. Handle the default case properly.
v5: Merged the DP handling along with platform colorspace
handling as per Shashank's comments.
v6: Reverted to old design of exposing all colorspaces to
userspace as per Ville's review comment
v7: Fixed a checkpatch complaint, Addressed Maarten' review
comment, updated the RB from Maarten and Jani's ack.
v8: Moved colorspace AVI Infoframe programming to drm core and
removed from driver as per Ville's suggestion.
v9: Added a check to only allow RGB colorpsaces to be set in
infoframe though the colorspace property. Since there is no output
csc property to control planar formats and it will be added later.
Changes for RGB->YUV conversion inside driver without userspace
knowledge is still supported. This is as per Ville's suggestion.
v10: Fixed an error in if check.
v11: Dropped the check for planar vs RGB and allow all the colorspaces.
Onus will be on userspace to pick whatever pipe output it is able to
drive.
v12: Added Ville's RB.
Signed-off-by: Uma Shankar <uma.shankar@intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1550596381-993-4-git-send-email-uma.shankar@intel.com
This adds colorspace information to HDMI AVI infoframe.
A helper function is added to program the same.
v2: Moved this to drm core instead of i915 driver.
v3: Exported the helper function.
v4: Added separate HDMI specific macro as per CTA spec.
This is separate from user exposed enum values. This is
as per Ville's suggestion.
v5: Appended BT709 and SMPTE 170M with YCC information as per Ville's
review comment to be clear and not to be confused with RGB.
v6: Added bit wise macro for various fields of colorimetry for easier
understanding and review as per Ville's comments. Moved the same out of
header file to avoid any namespace issues.
v7: Undef some macros to avoid any namespace collision as suggested by
Ville. Added Ville's RB.
Signed-off-by: Uma Shankar <uma.shankar@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1550596381-993-3-git-send-email-uma.shankar@intel.com
Create a new connector property to program colorspace to sink
devices. Modern sink devices support more than 1 type of
colorspace like 601, 709, BT2020 etc. This helps to switch
based on content type which is to be displayed. The decision
lies with compositors as to in which scenarios, a particular
colorspace will be picked.
This will be helpful mostly to switch to higher gamut colorspaces
like BT2020 when the media content is encoded as BT2020. Thereby
giving a good visual experience to users.
The expectation from userspace is that it should parse the EDID
and get supported colorspaces. Use this property and switch to the
one supported. Sink supported colorspaces should be retrieved by
userspace from EDID and driver will not explicitly expose them.
Basically the expectation from userspace is:
- Set up CRTC DEGAMMA/CTM/GAMMA to convert to some sink
colorspace
- Set this new property to let the sink know what it
converted the CRTC output to.
v2: Addressed Maarten and Ville's review comments. Enhanced
the colorspace enum to incorporate both HDMI and DP supported
colorspaces. Also, added a default option for colorspace.
v3: Removed Adobe references from enum definitions as per
Ville, Hans Verkuil and Jonas Karlman suggestions. Changed
Default to an unset state where driver will assign the colorspace
is not chosen by user, suggested by Ville and Maarten. Addressed
other misc review comments from Maarten. Split the changes to
have separate colorspace property for DP and HDMI.
v4: Addressed Chris and Ville's review comments, and created a
common colorspace property for DP and HDMI, filtered the list
based on the colorspaces supported by the respective protocol
standard.
v5: Made the property creation helper accept enum list based on
platform capabilties as suggested by Shashank. Consolidated HDMI
and DP property creation in the common helper.
v6: Addressed Shashank's review comments.
v7: Added defines instead of enum in uapi as per Brian Starkey's
suggestion in order to go with string matching at userspace. Updated
the commit message to add more details as well kernel docs.
v8: Addressed Maarten's review comments.
v9: Removed macro defines from uapi as per Brian Starkey and Daniel
Stone's comments and moved to drm include file. Moved back to older
design with exposing all HDMI colorspaces to userspace since infoframe
capability is there even on legacy platforms, as per Ville's review
comments.
v10: Fixed sparse warnings, updated the RB from Maarten and Jani's ack.
v11: Addressed Ville's review comments. Updated the Macro naming and
added DCI-P3 colorspace as well, defined in CTA 861.G spec.
v12: Appended BT709 and SMPTE 170M with YCC information as per Ville's
review comment to be clear and not to be confused with RGB.
v13: Reorder the colorspace macros.
v14: Removed DP as of now, will be added later once full support is
enabled, as per Ville's suggestion. Added Ville's RB.
Signed-off-by: Uma Shankar <uma.shankar@intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Shashank Sharma <shashank.sharma@intel.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/1550596381-993-2-git-send-email-uma.shankar@intel.com
In preparation to enabling -Wimplicit-fallthrough, mark switch
cases where we are expecting to fall through.
Warning level 3 was used: -Wimplicit-fallthrough=3
Notice that, in this particular case, the code comment is modified
in accordance with what GCC is expecting to find.
This patch is part of the ongoing efforts to enable
-Wimplicit-fallthrough.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20190215170546.GA30950@embeddedor
The current calculation for the video start delay in the current DSI driver
is that it is the total vertical size, minus the front porch and sync length,
plus 1. This equals to the active vertical size plus the back porch plus 1.
That 1 is coming in the Allwinner BSP from an variable that is set to 1.
However, if we look at the Allwinner BSP more closely, and especially in
the "legacy" code for the display (in drivers/video/sunxi/legacy/), we can
see that this variable is actually computed from the porches and the sync
minus 10, clamped between 8 and 100.
This fixes the start delay symptom we've seen on some panels (vblank
timeouts with vertical white stripes at the bottom of the panel).
Reviewed-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
Link: https://patchwork.freedesktop.org/patch/msgid/6e5f72e68f47ca0223877464bf12f0c3f3978de8.1549896081.git-series.maxime.ripard@bootlin.com
Pull EFI fixes from Ingo Molnar:
"This tree reverts a GICv3 commit (which was broken) and fixes it in
another way, by adding a memblock build-time entries quirk for ARM64"
* 'efi-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
efi/arm: Revert "Defer persistent reservations until after paging_init()"
arm64, mm, efi: Account for GICv3 LPI tables in static memblock reserve table
Pull x86 fixes from Ingo Molnar:
"Three changes:
- An UV fix/quirk to pull UV BIOS calls into the efi_runtime_lock
locking regime. (This done by aliasing __efi_uv_runtime_lock to
efi_runtime_lock, which should make the quirk nature obvious and
maintain the general policy that the EFI lock (name...) isn't
exposed to drivers.)
- Our version of MAGA: Make a.out Great Again.
- Add a new Intel model name enumerator to an upstream header to help
reduce dependencies going forward"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/platform/UV: Use efi_runtime_lock to serialise BIOS calls
x86/CPU: Add Icelake model number
x86/a.out: Clear the dump structure initially
Pull perf fixes from Ingo Molnar:
"Two fixes on the kernel side: fix an over-eager condition that failed
larger perf ring-buffer sizes, plus fix crashes in the Intel BTS code
for a corner case, found by fuzzing"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/core: Fix impossible ring-buffer sizes warning
perf/x86: Add check_period PMU callback
Pull powerpc fix from Michael Ellerman:
"Just one fix, for pgd/pud_present() which were broken on big endian
since v4.20, leading to possible data corruption.
Thanks to: Aneesh Kumar K.V., Erhard F., Jan Kara"
* tag 'powerpc-5.0-5' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/64s: Fix possible corruption on big endian due to pgd/pud_present()
Pull arch/csky fixes from Guo Ren:
"Here are some fixup patches for 5.0-rc6"
* tag 'csky-for-linus-5.0-rc6' of git://github.com/c-sky/csky-linux:
csky: Fixup dead loop in show_stack
csky: Fixup io-range page attribute for mmap("/dev/mem")
csky: coding convention: Use task_stack_page
csky: Fixup wrong pt_regs size
csky: Fixup _PAGE_GLOBAL bit for 610 tlb entry
Pull i2c fixes from Wolfram Sang:
"Two more driver bugfixes"
* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
i2c: bcm2835: Clear current buffer pointers and counts after a transfer
i2c: cadence: Fix the hold bit setting
Pull input fixes from Dmitry Torokhov:
- tweaks to Elan drivers (both PS/2 and I2C) to support new devices.
Also revert of one of IDs as that device should really be driven by
i2c-hid + hid-multitouch
- a few drivers have been switched to set_brightness_blocking() call
because they either were sleeping the their set_brightness()
implementation or used workqueue but were not canceling it on unbind.
- ps2-gpio and matrix_keypad needed to [properly] flush their works to
avoid potential use-after-free on unbind.
- other miscellaneous fixes.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
Input: elan_i2c - add ACPI ID for touchpad in Lenovo V330-15ISK
Input: st-keyscan - fix potential zalloc NULL dereference
Input: apanel - switch to using brightness_set_blocking()
Revert "Input: elan_i2c - add ACPI ID for touchpad in ASUS Aspire F5-573G"
Input: qt2160 - switch to using brightness_set_blocking()
Input: matrix_keypad - use flush_delayed_work()
Input: ps2-gpio - flush TX work when closing port
Input: cap11xx - switch to using set_brightness_blocking()
Input: elantech - enable 3rd button support on Fujitsu CELSIUS H780
Input: bma150 - register input device after setting private data
Input: pwm-vibra - stop regulator after disabling pwm, not before
Input: pwm-vibra - prevent unbalanced regulator
Input: snvs_pwrkey - allow selecting driver for i.MX 7D
Pull KVM fixes from Paolo Bonzini:
"A somewhat bigger ARM update, and the usual smattering of x86 bug
fixes"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
kvm: vmx: Fix entry number check for add_atomic_switch_msr()
KVM: x86: Recompute PID.ON when clearing PID.SN
KVM: nVMX: Restore a preemption timer consistency check
x86/kvm/nVMX: read from MSR_IA32_VMX_PROCBASED_CTLS2 only when it is available
KVM: arm64: Forbid kprobing of the VHE world-switch code
KVM: arm64: Relax the restriction on using stage2 PUD huge mapping
arm: KVM: Add missing kvm_stage2_has_pmd() helper
KVM: arm/arm64: vgic: Always initialize the group of private IRQs
arm/arm64: KVM: Don't panic on failure to properly reset system registers
arm/arm64: KVM: Allow a VCPU to fully reset itself
KVM: arm/arm64: Reset the VCPU without preemption and vcpu state loaded
arm64: KVM: Don't generate UNDEF when LORegion feature is present
KVM: arm/arm64: vgic: Make vgic_cpu->ap_list_lock a raw_spinlock
KVM: arm/arm64: vgic: Make vgic_dist->lpi_list_lock a raw_spinlock
KVM: arm/arm64: vgic: Make vgic_irq->irq_lock a raw_spinlock
Now that LEDs core allows "blocking" flavor of "set brightness" method we
can use it and get rid of private work item. As a bonus, we are no longer
forgetting to cancel it when we unbind the driver.
Reviewed-by: Sven Van Asbroeck <TheSven73@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
In v4.20 we changed our pgd/pud_present() to check for _PAGE_PRESENT
rather than just checking that the value is non-zero, e.g.:
static inline int pgd_present(pgd_t pgd)
{
- return !pgd_none(pgd);
+ return (pgd_raw(pgd) & cpu_to_be64(_PAGE_PRESENT));
}
Unfortunately this is broken on big endian, as the result of the
bitwise & is truncated to int, which is always zero because
_PAGE_PRESENT is 0x8000000000000000ul. This means pgd_present() and
pud_present() are always false at compile time, and the compiler
elides the subsequent code.
Remarkably with that bug present we are still able to boot and run
with few noticeable effects. However under some work loads we are able
to trigger a warning in the ext4 code:
WARNING: CPU: 11 PID: 29593 at fs/ext4/inode.c:3927 .ext4_set_page_dirty+0x70/0xb0
CPU: 11 PID: 29593 Comm: debugedit Not tainted 4.20.0-rc1 #1
...
NIP .ext4_set_page_dirty+0x70/0xb0
LR .set_page_dirty+0xa0/0x150
Call Trace:
.set_page_dirty+0xa0/0x150
.unmap_page_range+0xbf0/0xe10
.unmap_vmas+0x84/0x130
.unmap_region+0xe8/0x190
.__do_munmap+0x2f0/0x510
.__vm_munmap+0x80/0x110
.__se_sys_munmap+0x14/0x30
system_call+0x5c/0x70
The fix is simple, we need to convert the result of the bitwise & to
an int before returning it.
Thanks to Erhard, Jan Kara and Aneesh for help with debugging.
Fixes: da7ad366b4 ("powerpc/mm/book3s: Update pmd_present to look at _PAGE_PRESENT bit")
Cc: stable@vger.kernel.org # v4.20+
Reported-by: Erhard F. <erhard_f@mailbox.org>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Pull ARM SoC fixes from Arnd Bergmann:
"This week is a much smaller update, containing fixes only for TI OMAP,
NXP i.MX and Rockchips platforms:
omap:
- omap4 had problems with lost timer interrupts
- another IRQ handling issue with OMAP5
- A workaround for a regression in the pwm-omap-dmtimer driver
NXP i.MX:
- eMMC was broken on the new imx8mq-evk board
Rockchip:
- a fix for new dtc graph warnings and a regulator fix for rock64
- USB support broke on rk3328-rock64"
* tag 'armsoc-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc:
ARM: OMAP2+: fix lack of timer interrupts on CPU1 after hotplug
arm64: dts: imx8mq: Fix boot from eMMC
ARM: OMAP2+: Variable "reg" in function omap4_dsi_mux_pads() could be uninitialized
ARM: dts: Configure clock parent for pwm vibra
bus: ti-sysc: Fix timer handling with drop pm_runtime_irq_safe()
arm64: dts: rockchip: enable usb-host regulators at boot on rk3328-rock64
arm64: dts: rockchip: fix graph_port warning on rk3399 bob kevin and excavator
ARM: OMAP5+: Fix inverted nirq pin interrupts with irq_set_type
clocksource: timer-ti-dm: Fix pwm dmtimer usage of fck reparenting
ARM: dts: rockchip: remove qos_cif1 from rk3188 power-domain
Pull more nfsd fixes from Bruce Fields:
"Two small fixes, one for crashes using nfs/krb5 with older enctypes,
one that could prevent clients from reclaiming state after a kernel
upgrade"
* tag 'nfsd-5.0-2' of git://linux-nfs.org/~bfields/linux:
sunrpc: fix 4 more call sites that were using stack memory with a scatterlist
Revert "nfsd4: return default lease period"
Pull more NFS client fixes from Anna Schumaker:
"Three fixes this time.
Nicolas's is for xprtrdma completion vector allocation on single-core
systems. Greg's adds an error check when allocating a debugfs dentry.
And Ben's is an additional fix for nfs_page_async_flush() to prevent
pages from accidentally getting truncated.
Summary:
- Make sure Send CQ is allocated on an existing compvec
- Properly check debugfs dentry before using it
- Don't use page_file_mapping() after removing a page"
* tag 'nfs-for-5.0-4' of git://git.linux-nfs.org/projects/anna/linux-nfs:
NFS: Don't use page_file_mapping after removing the page
rpc: properly check debugfs dentry before using it
xprtrdma: Make sure Send CQ is allocated on an existing compvec
Pull auxdisplay fix from Miguel Ojeda:
"Fix potential user-after-free on ht16k33 module unload. Reported by
Sven Van Asbroeck"
* tag 'auxdisplay-for-linus-v5.0-rc7' of git://github.com/ojeda/linux:
auxdisplay: ht16k33: fix potential user-after-free on module unload
Pull compiler attributes fixes from Miguel Ojeda:
"Clean the new GCC 9 -Wmissing-attributes warnings
The upcoming GCC 9 release extends the -Wmissing-attributes warnings
(enabled by -Wall) to C and aliases: it warns when particular function
attributes are missing in the aliases but not in their target, e.g.:
void __cold f(void) {}
void __alias("f") g(void);
diagnoses:
warning: 'g' specifies less restrictive attribute than
its target 'f': 'cold' [-Wmissing-attributes]
These patch series clean these new warnings. Most of them are caused
by the module_init/exit macros"
Link: https://lore.kernel.org/lkml/20190125104353.2791-1-labbott@redhat.com/
* tag 'compiler-attributes-for-linus-v5.0-rc7' of git://github.com/ojeda/linux:
include/linux/module.h: copy __init/__exit attrs to init/cleanup_module
Compiler Attributes: add support for __copy (gcc >= 9)
lib/crc32.c: mark crc32_le_base/__crc32c_le_base aliases as __pure
In the irqchip and EFI code, we have what basically amounts to a quirk
to work around a peculiarity in the GICv3 architecture, which permits
the system memory address of LPI tables to be programmable only once
after a CPU reset. This means kexec kernels must use the same memory
as the first kernel, and thus ensure that this memory has not been
given out for other purposes by the time the ITS init code runs, which
is not very early for secondary CPUs.
On systems with many CPUs, these reservations could overflow the
memblock reservation table, and this was addressed in commit:
eff8962888 ("efi/arm: Defer persistent reservations until after paging_init()")
However, this turns out to have made things worse, since the allocation
of page tables and heap space for the resized memblock reservation table
itself may overwrite the regions we are attempting to reserve, which may
cause all kinds of corruption, also considering that the ITS will still
be poking bits into that memory in response to incoming MSIs.
So instead, let's grow the static memblock reservation table on such
systems so it can accommodate these reservations at an earlier time.
This will permit us to revert the above commit in a subsequent patch.
[ mingo: Minor cleanups. ]
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Will Deacon <will.deacon@arm.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20190215123333.21209-2-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull SCSI fixes from James Bottomley:
"Two fairly small fixes: the qla one is a panic inducing use after free
and the entropy fix may seem minor but it has had huge userspace
impact thanks to an unrelated change in openssl that causes sshd to
refuse logins until it has enough entropy for the session keys, which
causes tens of minutes delay before the affected systems allow logins
after reboot"
* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
scsi: qla2xxx: Fix panic from use after free in qla2x00_async_tm_cmd
scsi: sd: fix entropy gathering for most rotational disks
While trying to reproduce a reported kernel panic on arm64, I discovered
that AUTH_GSS basically doesn't work at all with older enctypes on arm64
systems with CONFIG_VMAP_STACK enabled. It turns out there still a few
places using stack memory with scatterlists, causing krb5_encrypt() and
krb5_decrypt() to produce incorrect results (or a BUG if CONFIG_DEBUG_SG
is enabled).
Tested with cthon on v4.0/v4.1/v4.2 with krb5/krb5i/krb5p using
des3-cbc-sha1 and arcfour-hmac-md5.
Signed-off-by: Scott Mayhew <smayhew@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Fix omap4 and later lost cpu1 interrupts for periodic timer
A fix from Russell that took a while to get applied into fixes as
I thought Russell is merging this one.
* tag 'omap-for-v5.0/fixes-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap:
ARM: OMAP2+: fix lack of timer interrupts on CPU1 after hotplug
The upcoming GCC 9 release extends the -Wmissing-attributes warnings
(enabled by -Wall) to C and aliases: it warns when particular function
attributes are missing in the aliases but not in their target.
In particular, it triggers for all the init/cleanup_module
aliases in the kernel (defined by the module_init/exit macros),
ending up being very noisy.
These aliases point to the __init/__exit functions of a module,
which are defined as __cold (among other attributes). However,
the aliases themselves do not have the __cold attribute.
Since the compiler behaves differently when compiling a __cold
function as well as when compiling paths leading to calls
to __cold functions, the warning is trying to point out
the possibly-forgotten attribute in the alias.
In order to keep the warning enabled, we decided to silence
this case. Ideally, we would mark the aliases directly
as __init/__exit. However, there are currently around 132 modules
in the kernel which are missing __init/__exit in their init/cleanup
functions (either because they are missing, or for other reasons,
e.g. the functions being called from somewhere else); and
a section mismatch is a hard error.
A conservative alternative was to mark the aliases as __cold only.
However, since we would like to eventually enforce __init/__exit
to be always marked, we chose to use the new __copy function
attribute (introduced by GCC 9 as well to deal with this).
With it, we copy the attributes used by the target functions
into the aliases. This way, functions that were not marked
as __init/__exit won't have their aliases marked either,
and therefore there won't be a section mismatch.
Note that the warning would go away marking either the extern
declaration, the definition, or both. However, we only mark
the definition of the alias, since we do not want callers
(which only see the declaration) to be compiled as if the function
was __cold (and therefore the paths leading to those calls
would be assumed to be unlikely).
Link: https://lore.kernel.org/lkml/20190123173707.GA16603@gmail.com/
Link: https://lore.kernel.org/lkml/20190206175627.GA20399@gmail.com/
Suggested-by: Martin Sebor <msebor@gcc.gnu.org>
Acked-by: Jessica Yu <jeyu@kernel.org>
Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
From the GCC manual:
copy
copy(function)
The copy attribute applies the set of attributes with which function
has been declared to the declaration of the function to which
the attribute is applied. The attribute is designed for libraries
that define aliases or function resolvers that are expected
to specify the same set of attributes as their targets. The copy
attribute can be used with functions, variables, or types. However,
the kind of symbol to which the attribute is applied (either
function or variable) must match the kind of symbol to which
the argument refers. The copy attribute copies only syntactic and
semantic attributes but not attributes that affect a symbol’s
linkage or visibility such as alias, visibility, or weak.
The deprecated attribute is also not copied.
https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html
The upcoming GCC 9 release extends the -Wmissing-attributes warnings
(enabled by -Wall) to C and aliases: it warns when particular function
attributes are missing in the aliases but not in their target, e.g.:
void __cold f(void) {}
void __alias("f") g(void);
diagnoses:
warning: 'g' specifies less restrictive attribute than
its target 'f': 'cold' [-Wmissing-attributes]
Using __copy(f) we can copy the __cold attribute from f to g:
void __cold f(void) {}
void __copy(f) __alias("f") g(void);
This attribute is most useful to deal with situations where an alias
is declared but we don't know the exact attributes the target has.
For instance, in the kernel, the widely used module_init/exit macros
define the init/cleanup_module aliases, but those cannot be marked
always as __init/__exit since some modules do not have their
functions marked as such.
Suggested-by: Martin Sebor <msebor@gcc.gnu.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
The upcoming GCC 9 release extends the -Wmissing-attributes warnings
(enabled by -Wall) to C and aliases: it warns when particular function
attributes are missing in the aliases but not in their target.
In particular, it triggers here because crc32_le_base/__crc32c_le_base
aren't __pure while their target crc32_le/__crc32c_le are.
These aliases are used by architectures as a fallback in accelerated
versions of CRC32. See commit 9784d82db3 ("lib/crc32: make core crc32()
routines weak so they can be overridden").
Therefore, being fallbacks, it is likely that even if the aliases
were called from C, there wouldn't be any optimizations possible.
Currently, the only user is arm64, which calls this from asm.
Still, marking the aliases as __pure makes sense and is a good idea
for documentation purposes and possible future optimizations,
which also silences the warning.
Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Tested-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
On module unload/remove, we need to ensure that work does not run
after we have freed resources. Concretely, cancel_delayed_work()
may return while the callback function is still running.
From kernel/workqueue.c:
The work callback function may still be running on return,
unless it returns true and the work doesn't re-arm itself.
Explicitly flush or use cancel_delayed_work_sync() to wait on it.
Link: https://lore.kernel.org/lkml/20190204220952.30761-1-TheSven73@googlemail.com/
Reported-by: Sven Van Asbroeck <thesven73@gmail.com>
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Sven Van Asbroeck <TheSven73@gmail.com>
Acked-by: Robin van der Gracht <robin@protonic.nl>
Signed-off-by: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
