| Age | Commit message (Collapse) | Author |
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When a task which has used the FPU at some point in its past takes a
signal the kernel would previously always require the task to take
ownership of the FPU whilst setting up or restoring from the sigcontext.
That means that if the task has not used the FPU within this timeslice
then the kernel would enable the FPU, restore the task's FP context into
FPU registers and then save them into the sigcontext. This seems
inefficient, and if the signal handler doesn't use FP then enabling the
FPU & the extra memory accesses are entirely wasted work.
This patch modifies the sigcontext setup & restore code to copy directly
between the tasks saved FP context & the sigcontext for any tasks which
have used FP in the past but are not currently the FPU owner (ie. have
not used FP in this timeslice).
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Reviewed-by: Qais Yousef <qais.yousef@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6423/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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These functions aren't directly related to the FPU emulator at all, they
simply copy between a thread's saved context & a sigcontext. Thus move
them to the appropriate signal files & rename them accordingly. This
makes it clearer that the functions don't require the FPU emulator in
any way.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Reviewed-by: Qais Yousef <qais.yousef@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6422/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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The hard-coded offsets mentioned in this comment seem to not exist
anymore, so remove mention of them from the comment.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Reviewed-by: Qais Yousef <qais.yousef@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6421/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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This patch replaces the fpureg_t typedef with a "union fpureg" enabling
easier access to 32 & 64 bit values. This allows the access macros used
in cp1emu.c to be simplified somewhat. It will also make it easier to
expand the width of the FP registers as will be done in a future
patch in order to support the 128 bit registers introduced with MSA.
No behavioural change is intended by this patch.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Reviewed-by: Qais Yousef <qais.yousef@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6532/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Reviewed-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6401/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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When userland uses syscall() to perform an indirect system call
the actually system call that needs to be checked by the filter
is on the first argument. The kernel code needs to handle this case
by looking at the original syscall number in v0 and if it's
NR_syscall, then it needs to examine the first argument to
identify the real system call that will be executed.
Similarly, we need to 'virtually' shift the syscall() arguments
so the syscall_get_arguments() function can fetch the correct
arguments for the indirect system call.
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Reviewed-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6404/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Reviewed-by: Paul Burton <paul.burton@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6399/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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MIPS now has the infrastructure for dynamic seccomp-bpf
filtering
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Reviewed-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6400/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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Add _TIF_SECCOMP flag to _TIF_WORK_SYSCALL_ENTRY to indicate
that the system call needs to be checked against a seccomp filter.
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Reviewed-by: Paul Burton <paul.burton@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6405/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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This effectively renames __syscall_get_arch to syscall_get_arch
and implements a compatible interface for the seccomp API.
The seccomp code (kernel/seccomp.c) expects a syscall_get_arch
function to be defined for every architecture, so we drop
the leading underscores from the existing function.
This also makes use of the 'task' argument to determine the type
the process instead of assuming the process has the same
characteristics as the kernel it's running on.
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Reviewed-by: Paul Burton <paul.burton@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6398/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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The syscall_rollback function is used by seccomp-bpf but it was never
added for MIPS. It doesn't need to do anything as none of the registers
are clobbered if the system call has been denied by the seccomp filter.
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Reviewed-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6403/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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CONFIG_MIPS_CPS is a better option for systems where it is supported,
which as far as I am aware should be all systems where CONFIG_MIPS_CMP
could provide any value (ie. where there are multiple cores for YAMON to
bring up). This option is therefore deprecated, and marked as such. It
is left intact for the time being in order to provide a fallback should
someone find a system where CONFIG_MIPS_CPS will not function (ie. where
the reset vector cannot be moved), and should be removed entirely in the
future assuming that does not happen.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6369/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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Commit f55afb0969cc "MIPS: Clean up MIPS MT and CMP configuration
options." introduced a dependency upon MIPS_MT_SMP (ie. SMVP) for the
MIPS_CMP (ie. CMP framework support) Kconfig option. It did not specify
why, and that dependency is bogus. It is perfectly valid to have a
multi-core system with the YAMON bootloader but without MT support -
an example of this would be any multi-core proAptiv bitstream running on
a Malta. Forcing MT support to be enabled in a kernel for such a system
is incorrect. I suspect that the dependency was actually meant to
reflect the fact that YAMON will only bind 1 TC per VPE on an MT system,
and only describe those 1:1 TC:VPE pairs as CPUs through the AMON
interface. Thus an SMTC kernel makes little sense on a system using
MIPS_CMP, and the Kconfig dependencies should reflect that rather than
introducing the bogus SMVP dependency.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6368/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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The prior help text introduced in commit f55afb0969cc "MIPS: Clean up
MIPS MT and CMP configuration options." reads as though this option
enables the kernel to make use of the CM hardware, which is not true.
What it actually does is allow the kernel to interact with the YAMON
bootloader which actually interacts with the CM hardware to bring up
secondary cores. Re-introduce the word "framework" which that commit
removed to avoid misleading people.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6367/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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This header was used only by Malta but is used no longer. Remove it. It
was also included unnecessarily in irq-gic.c, so that include is also
removed.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6366/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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This patch simply attempts to register the MIPS Coherent Processing
System SMP implementation when it is enabled. If registering that fails
for some reason (like the Kconfig option being disabled or a lack of
hardware support) then we fall back to the same SMP implementations as
before.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6365/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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When CPC support is compiled into the kernel (ie. CONFIG_MIPS_CPC=y),
probe the CPC on boot for Malta in order to allow any users of the CPC
to detect its presence & function correctly.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6363/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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Remove the Malta-specific CM probe code and instead make use of the
newly added generic CM code.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6364/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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This patch introduces a new SMP implementation for systems implementing
the MIPS Coherent Processing System architecture. The kernel will make
use of the Coherence Manager, Cluster Power Controller & Global
Interrupt Controller in order to detect, bring up & make use of other
cores in the system. SMTC is not supported, so only a single TC per VPE
in the system is used. That is, this option enables an SMVP style setup
but across multiple cores.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6362/
Patchwork: https://patchwork.linux-mips.org/patch/6611/
Patchwork: https://patchwork.linux-mips.org/patch/6651/
Patchwork: https://patchwork.linux-mips.org/patch/6652/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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The vpe_id field of struct cpuinfo_mips is only present when one of
CONFIG_MIPS_MT_{SMP,SMTC} is enabled. That means that any code accessing
which may compile without MT is currently forced to use an #ifdef.
Instead this patch provides an accessor macro, #ifdef'd appropriately
to prevent further #ifdef's elsewhere.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/6646/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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Some applications didn't expect recvmsg() on a non blocking socket
could return -EINTR. This possibility was added as a side effect
of commit b3ca9b02b00704 ("net: fix multithreaded signal handling in
unix recv routines").
To hit this bug, you need to be a bit unlucky, as the u->readlock
mutex is usually held for very small periods.
Fixes: b3ca9b02b00704 ("net: fix multithreaded signal handling in unix recv routines")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Rainer Weikusat <rweikusat@mobileactivedefense.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Thomas Petazzoni says:
====================
net: mvneta: fix usage as a module
The following set of two patches fix the usage of the mvneta driver
when built as a module, and used in RGMII configurations. It is
somewhat similar to a previous fix that was made by Arnaud Patard, but
which was limited to SGMII configurations.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
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The mvneta driver currently uses of_iomap(), which has two drawbacks:
it doesn't request the resource, and it isn't devm-style so some error
handling is needed.
This commit switches to use devm_ioremap_resource() instead, which
automatically requests the resource (so the I/O registers region shows
up properly in /proc/iomem), and also is devm-style, which allows to
get rid of some error handling to unmap the I/O registers region.
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Commit 5445eaf309ff ('mvneta: Try to fix mvneta when compiled as
module') fixed the mvneta driver to make it work properly when loaded
as a module in SGMII configuration, which was tested successful by the
author on the Armada XP OpenBlocks AX3, which uses SGMII.
However, it turns out that the Armada XP GP, which uses RGMII, is
affected by a similar problem: its SERDES configuration is lost when
mvneta is loaded as a module, because this configuration is set by the
bootloader, and then lost because the clock is gated by the clock
framework until the mvneta driver is loaded again and the clock is
re-enabled.
However, it turns out that for the RGMII case, setting the SERDES
configuration is not sufficient: the PCS enable bit in the
MVNETA_GMAC_CTRL_2 register must also be set, like in the SGMII
configuration.
Therefore, this commit reworks the SGMII/RGMII initialization: the
only difference between the two now is a different SERDES
configuration, all the rest is identical.
In detail, to achieve this, the commit:
* Renames MVNETA_SGMII_SERDES_CFG to MVNETA_SERDES_CFG because it is
not specific to SGMII, but also used on RGMII configurations.
* Adds a MVNETA_RGMII_SERDES_PROTO definition, that must be used as
the MVNETA_SERDES_CFG value in RGMII configurations.
* Removes the mvneta_gmac_rgmii_set() and mvneta_port_sgmii_config()
functions, and instead directly do the SGMII/RGMII configuration in
mvneta_port_up(), from where those functions where called. It is
worth mentioning that mvneta_gmac_rgmii_set() had an 'enable'
parameter that was always passed as '1', so it was pretty useless.
* Reworks the mvneta_port_up() function to set the MVNETA_SERDES_CFG
register to the appropriate value depending on the RGMII vs. SGMII
configuration. It also unconditionally set the PCS_ENABLE bit (was
already done for SGMII, but is now also needed for RGMII), and sets
the PORT_RGMII bit (which was already done for both SGMII and
RGMII).
This commit was successfully tested with mvneta compiled as a module,
on both the OpenBlocks AX3 (SGMII configuration) and the Armada XP GP
(RGMII configuration).
Reported-by: Steve McIntyre <steve@einval.com>
Cc: stable@vger.kernel.org # 3.11.x: 5445eaf309ff mvneta: Try to fix mvneta when compiled as module
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Bit 3 of the MVNETA_GMAC_CTRL_2 is actually used to enable the PCS,
not the PSC: there was a typo in the name of the define, which this
commit fixes.
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The cypress PS/2 trackpad models supported by the cypress_ps2 driver
emulate BTN_RIGHT events in firmware based on the finger position, as part
of this no motion events are sent when the finger is in the button area.
The INPUT_PROP_BUTTONPAD property is there to indicate to userspace that
BTN_RIGHT events should be emulated in userspace, which is not necessary
in this case.
When INPUT_PROP_BUTTONPAD is advertised userspace will wait for a motion
event before propagating the button event higher up the stack, as it needs
current abs x + y data for its BTN_RIGHT emulation. Since in the
cypress_ps2 pads don't report motion events in the button area, this means
that clicks in the button area end up being ignored, so
INPUT_PROP_BUTTONPAD actually causes problems for these touchpads, and
removing it fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=76341
Reported-by: Adam Williamson <awilliam@redhat.com>
Tested-by: Adam Williamson <awilliam@redhat.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
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Including hardware acceleration features in vlan_features breaks
stacked vlans (Q-in-Q) by marking the bottom vlan interface as
capable of acceleration. This causes one of the tags to be lost
and the packets are sent with a sing vlan header.
CC: Nithin Nayak Sujir <nsujir@broadcom.com>
CC: Michael Chan <mchan@broadcom.com>
Signed-off-by: Vlad Yasevich <vyasevic@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Commit 10ddceb22ba (ip_tunnel:multicast process cause panic due
to skb->_skb_refdst NULL pointer) removed dst-drop call from
ip-tunnel-recv.
Following commit reintroduce dst-drop and fix the original bug by
checking loopback packet before releasing dst.
Original bug: https://bugzilla.kernel.org/show_bug.cgi?id=70681
CC: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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The ARM EFI boot stub doesn't need to care about the efi_early
infrastructure that x86 requires in order to do mixed mode thunking. So
wrap everything up in an efi_call_early() macro.
This allows x86 to do the necessary indirection jumps to call whatever
firmware interface is necessary (native or mixed mode), but also allows
the ARM folks to mask the fact that they don't support relocation in the
boot stub and need to pass 'sys_table_arg' to every function.
[ hpa: there are no object code changes from this patch ]
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Link: http://lkml.kernel.org/r/20140326091011.GB2958@console-pimps.org
Cc: Roy Franz <roy.franz@linaro.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
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'regulator/topic/tps6524x', 'regulator/topic/tps6586x', 'regulator/topic/tps65910', 'regulator/topic/tps80031', 'regulator/topic/wm831x', 'regulator/topic/wm8350' and 'regulator/topic/wm8994' into regulator-next
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'regulator/topic/st-pwm', 'regulator/topic/ti-abb', 'regulator/topic/tps51632', 'regulator/topic/tps62360', 'regulator/topic/tps6507x', 'regulator/topic/tps65090' and 'regulator/topic/tps65217' into regulator-next
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'regulator/topic/max8997', 'regulator/topic/max8998', 'regulator/topic/mc13xxx', 'regulator/topic/pfuze100', 'regulator/topic/rc5t583' and 'regulator/topic/s2mps11' into regulator-next
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'regulator/topic/max77686', 'regulator/topic/max77693', 'regulator/topic/max8649', 'regulator/topic/max8660', 'regulator/topic/max8907', 'regulator/topic/max8925' and 'regulator/topic/max8952' into regulator-next
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'regulator/topic/enable', 'regulator/topic/fan53555', 'regulator/topic/fixed', 'regulator/topic/gpio', 'regulator/topic/lp3971', 'regulator/topic/lp872x' and 'regulator/topic/max14577' into regulator-next
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'regulator/topic/da9052', 'regulator/topic/da9055', 'regulator/topic/da9063', 'regulator/topic/da9210', 'regulator/topic/db8500' and 'regulator/topic/dbx500' into regulator-next
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'regulator/topic/88pm8607', 'regulator/topic/aat2870', 'regulator/topic/act8865', 'regulator/topic/anatop', 'regulator/topic/arizona', 'regulator/topic/as3711' and 'regulator/topic/as3722' into regulator-next
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The voltages in aat2870_ldo_voltages table are in ascendant order, so use
regulator_map_voltage_ascend.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
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Make pata_arasan_cf host driver depend on ARCH_SPEAR13XX config
option as ARASAN CompactFlash PATA support is specific to ST
SPEAr13xx SoCs and the driver to work requires suitable device
tree node (or platform device) to be defined. Additionally
allow the driver build if COMPILE_TEST config option is set.
Cc: Viresh Kumar <viresh.linux@gmail.com>
Cc: Shiraz Hashim <shiraz.hashim@st.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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This driver sets the SPI_MASTER_HALF_DUPLEX flag, so the spi core will check
transfers to ensure they are not full duplex.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@linaro.org>
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Unreferenced casts of void * types are unnecessary so remove them.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing fix from Steven Rostedt:
"While on my flight to Linux Collaboration Summit, I was working on my
slides for the event trigger tutorial. I booted a 3.14-rc7 kernel to
perform what I wanted to teach and cut and paste it into my slides.
When I tried the traceon event trigger with a condition attached to it
(turns tracing on only if a field of the trigger event matches a
condition set by the user), nothing happened. Tracing would not turn
on. I stopped working on my presentation in order to find what was
wrong.
It ended up being the way trace event triggers work when they have
conditions. Instead of copying the fields, the condition code just
looks at the fields that were copied into the ring buffer. This works
great, unless tracing is off. That's because when the event is
reserved on the ring buffer, the ring buffer returns a NULL pointer,
this tells the tracing code that the ring buffer is disabled. This
ends up being a problem for the traceon trigger if it is using this
information to check its condition.
Luckily the code that checks if tracing is on returns the ring buffer
to use (because the ring buffer is determined by the event file also
passed to that field). I was able to easily solve this bug by
checking in that helper function if the returned ring buffer entry is
NULL, and if so, also check the file flag if it has a trace event
trigger condition, and if so, to pass back a temp ring buffer to use.
This will allow the trace event trigger condition to still test the
event fields, but nothing will be recorded"
* tag 'trace-fixes-v3.14-rc7-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing: Fix traceon trigger condition to actually turn tracing on
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hpriv->plat_data is 'void *' so there is no need to cast it to
'struct ecx_plat_data *'.
Cc: Mark Langsdorf <mark.langsdorf@calxeda.com>
Cc: Rob Herring <robh@kernel.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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cpufreq_notify_transition() and cpufreq_notify_post_transition() shouldn't be
called directly by cpufreq drivers anymore and so these should be marked static.
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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CPUFreq core has new infrastructure that would guarantee serialized calls to
target() or target_index() callbacks. These are called
cpufreq_freq_transition_begin() and cpufreq_freq_transition_end().
This patch converts existing drivers to use these new set of routines.
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Whenever we change the frequency of a CPU, we call the PRECHANGE and POSTCHANGE
notifiers. They must be serialized, i.e. PRECHANGE and POSTCHANGE notifiers
should strictly alternate, thereby preventing two different sets of PRECHANGE or
POSTCHANGE notifiers from interleaving arbitrarily.
The following examples illustrate why this is important:
Scenario 1:
-----------
A thread reading the value of cpuinfo_cur_freq, will call
__cpufreq_cpu_get()->cpufreq_out_of_sync()->cpufreq_notify_transition()
The ondemand governor can decide to change the frequency of the CPU at the same
time and hence it can end up sending the notifications via ->target().
If the notifiers are not serialized, the following sequence can occur:
- PRECHANGE Notification for freq A (from cpuinfo_cur_freq)
- PRECHANGE Notification for freq B (from target())
- Freq changed by target() to B
- POSTCHANGE Notification for freq B
- POSTCHANGE Notification for freq A
We can see from the above that the last POSTCHANGE Notification happens for freq
A but the hardware is set to run at freq B.
Where would we break then?: adjust_jiffies() in cpufreq.c & cpufreq_callback()
in arch/arm/kernel/smp.c (which also adjusts the jiffies). All the
loops_per_jiffy calculations will get messed up.
Scenario 2:
-----------
The governor calls __cpufreq_driver_target() to change the frequency. At the
same time, if we change scaling_{min|max}_freq from sysfs, it will end up
calling the governor's CPUFREQ_GOV_LIMITS notification, which will also call
__cpufreq_driver_target(). And hence we end up issuing concurrent calls to
->target().
Typically, platforms have the following logic in their ->target() routines:
(Eg: cpufreq-cpu0, omap, exynos, etc)
A. If new freq is more than old: Increase voltage
B. Change freq
C. If new freq is less than old: decrease voltage
Now, if the two concurrent calls to ->target() are X and Y, where X is trying to
increase the freq and Y is trying to decrease it, we get the following race
condition:
X.A: voltage gets increased for larger freq
Y.A: nothing happens
Y.B: freq gets decreased
Y.C: voltage gets decreased
X.B: freq gets increased
X.C: nothing happens
Thus we can end up setting a freq which is not supported by the voltage we have
set. That will probably make the clock to the CPU unstable and the system might
not work properly anymore.
This patch introduces a set of synchronization primitives to serialize frequency
transitions, which are to be used as shown below:
cpufreq_freq_transition_begin();
//Perform the frequency change
cpufreq_freq_transition_end();
The _begin() call sends the PRECHANGE notification whereas the _end() call sends
the POSTCHANGE notification. Also, all the necessary synchronization is handled
within these calls. In particular, even drivers which set the ASYNC_NOTIFICATION
flag can also use these APIs for performing frequency transitions (ie., you can
call _begin() from one task, and call the corresponding _end() from a different
task).
The actual synchronization underneath is not that complicated:
The key challenge is to allow drivers to begin the transition from one thread
and end it in a completely different thread (this is to enable drivers that do
asynchronous POSTCHANGE notification from bottom-halves, to also use the same
interface).
To achieve this, a 'transition_ongoing' flag, a 'transition_lock' spinlock and a
wait-queue are added per-policy. The flag and the wait-queue are used in
conjunction to create an "uninterrupted flow" from _begin() to _end(). The
spinlock is used to ensure that only one such "flow" is in flight at any given
time. Put together, this provides us all the necessary synchronization.
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Make sata_highbank host driver depend on ARCH_HIGHBANK config option
as Calxeda Highbank SATA support is specific to Calxeda Highbank
SoCs and the driver to work requires suitable device tree node to
be defined. Additionally allow the driver build if COMPILE_TEST
config option is set.
Cc: Mark Langsdorf <mark.langsdorf@calxeda.com>
Cc: Rob Herring <robh@kernel.org>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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Ensure that no timer callback is running since we are about to free
the timer structure. We cannot guarantee that the call back is called
on the CPU where the timer is running.
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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During suspend, we first stop governors and then suspend cpufreq drivers and
resume must be exactly opposite of that. i.e. resume drivers first and then
start governors.
But the current code in resume enables governors first and then resume drivers.
Fix it be changing code sequence there.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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