<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/drivers/clocksource, branch linux-6.10.y</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>clocksource/drivers/qcom: Add missing iounmap() on errors in msm_dt_timer_init()</title>
<updated>2024-10-04T14:32:37+00:00</updated>
<author>
<name>Ankit Agrawal</name>
<email>agrawal.ag.ankit@gmail.com</email>
</author>
<published>2024-07-13T09:57:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=59c236c6aa28a811a42046f09a32b33aad7c5e6e'/>
<id>59c236c6aa28a811a42046f09a32b33aad7c5e6e</id>
<content type='text'>
[ Upstream commit ca140a0dc0a18acd4653b56db211fec9b2339986 ]

Add the missing iounmap() when clock frequency fails to get read by the
of_property_read_u32() call, or if the call to msm_timer_init() fails.

Fixes: 6e3321631ac2 ("ARM: msm: Add DT support to msm_timer")
Signed-off-by: Ankit Agrawal &lt;agrawal.ag.ankit@gmail.com&gt;
Reviewed-by: Konrad Dybcio &lt;konrad.dybcio@linaro.org&gt;
Link: https://lore.kernel.org/r/20240713095713.GA430091@bnew-VirtualBox
Signed-off-by: Daniel Lezcano &lt;daniel.lezcano@linaro.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit ca140a0dc0a18acd4653b56db211fec9b2339986 ]

Add the missing iounmap() when clock frequency fails to get read by the
of_property_read_u32() call, or if the call to msm_timer_init() fails.

Fixes: 6e3321631ac2 ("ARM: msm: Add DT support to msm_timer")
Signed-off-by: Ankit Agrawal &lt;agrawal.ag.ankit@gmail.com&gt;
Reviewed-by: Konrad Dybcio &lt;konrad.dybcio@linaro.org&gt;
Link: https://lore.kernel.org/r/20240713095713.GA430091@bnew-VirtualBox
Signed-off-by: Daniel Lezcano &lt;daniel.lezcano@linaro.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>clocksource: hyper-v: Use lapic timer in a TDX VM without paravisor</title>
<updated>2024-09-18T17:25:12+00:00</updated>
<author>
<name>Dexuan Cui</name>
<email>decui@microsoft.com</email>
</author>
<published>2024-06-21T06:16:14+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1bb24288b6253d9a15132012d914c384a80f4e69'/>
<id>1bb24288b6253d9a15132012d914c384a80f4e69</id>
<content type='text'>
commit 7f828d5fff7d24752e1ecf6bebb6617a81f97b93 upstream.

In a TDX VM without paravisor, currently the default timer is the Hyper-V
timer, which depends on the slow VM Reference Counter MSR: the Hyper-V TSC
page is not enabled in such a VM because the VM uses Invariant TSC as a
better clocksource and it's challenging to mark the Hyper-V TSC page shared
in very early boot.

Lower the rating of the Hyper-V timer so the local APIC timer becomes the
the default timer in such a VM, and print a warning in case Invariant TSC
is unavailable in such a VM. This change should cause no perceivable
performance difference.

Cc: stable@vger.kernel.org # 6.6+
Reviewed-by: Roman Kisel &lt;romank@linux.microsoft.com&gt;
Signed-off-by: Dexuan Cui &lt;decui@microsoft.com&gt;
Reviewed-by: Michael Kelley &lt;mhklinux@outlook.com&gt;
Link: https://lore.kernel.org/r/20240621061614.8339-1-decui@microsoft.com
Signed-off-by: Wei Liu &lt;wei.liu@kernel.org&gt;
Message-ID: &lt;20240621061614.8339-1-decui@microsoft.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 7f828d5fff7d24752e1ecf6bebb6617a81f97b93 upstream.

In a TDX VM without paravisor, currently the default timer is the Hyper-V
timer, which depends on the slow VM Reference Counter MSR: the Hyper-V TSC
page is not enabled in such a VM because the VM uses Invariant TSC as a
better clocksource and it's challenging to mark the Hyper-V TSC page shared
in very early boot.

Lower the rating of the Hyper-V timer so the local APIC timer becomes the
the default timer in such a VM, and print a warning in case Invariant TSC
is unavailable in such a VM. This change should cause no perceivable
performance difference.

Cc: stable@vger.kernel.org # 6.6+
Reviewed-by: Roman Kisel &lt;romank@linux.microsoft.com&gt;
Signed-off-by: Dexuan Cui &lt;decui@microsoft.com&gt;
Reviewed-by: Michael Kelley &lt;mhklinux@outlook.com&gt;
Link: https://lore.kernel.org/r/20240621061614.8339-1-decui@microsoft.com
Signed-off-by: Wei Liu &lt;wei.liu@kernel.org&gt;
Message-ID: &lt;20240621061614.8339-1-decui@microsoft.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>clocksource/drivers/timer-of: Remove percpu irq related code</title>
<updated>2024-09-12T09:13:07+00:00</updated>
<author>
<name>Daniel Lezcano</name>
<email>daniel.lezcano@linaro.org</email>
</author>
<published>2024-08-19T10:03:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e47d7f80b4d734cd4744b5ee9cb944f7a32bd020'/>
<id>e47d7f80b4d734cd4744b5ee9cb944f7a32bd020</id>
<content type='text'>
commit 471ef0b5a8aaca4296108e756b970acfc499ede4 upstream.

GCC's named address space checks errors out with:

drivers/clocksource/timer-of.c: In function ‘timer_of_irq_exit’:
drivers/clocksource/timer-of.c:29:46: error: passing argument 2 of
‘free_percpu_irq’ from pointer to non-enclosed address space
  29 |                 free_percpu_irq(of_irq-&gt;irq, clkevt);
     |                                              ^~~~~~
In file included from drivers/clocksource/timer-of.c:8:
./include/linux/interrupt.h:201:43: note: expected ‘__seg_gs void *’
but argument is of type ‘struct clock_event_device *’
 201 | extern void free_percpu_irq(unsigned int, void __percpu *);
     |                                           ^~~~~~~~~~~~~~~
drivers/clocksource/timer-of.c: In function ‘timer_of_irq_init’:
drivers/clocksource/timer-of.c:74:51: error: passing argument 4 of
‘request_percpu_irq’ from pointer to non-enclosed address space
  74 |                                    np-&gt;full_name, clkevt) :
     |                                                   ^~~~~~
./include/linux/interrupt.h:190:56: note: expected ‘__seg_gs void *’
but argument is of type ‘struct clock_event_device *’
 190 |                    const char *devname, void __percpu *percpu_dev_id)

Sparse warns about:

timer-of.c:29:46: warning: incorrect type in argument 2 (different address spaces)
timer-of.c:29:46:    expected void [noderef] __percpu *
timer-of.c:29:46:    got struct clock_event_device *clkevt
timer-of.c:74:51: warning: incorrect type in argument 4 (different address spaces)
timer-of.c:74:51:    expected void [noderef] __percpu *percpu_dev_id
timer-of.c:74:51:    got struct clock_event_device *clkevt

It appears the code is incorrect as reported by Uros Bizjak:

"The referred code is questionable as it tries to reuse
the clkevent pointer once as percpu pointer and once as generic
pointer, which should be avoided."

This change removes the percpu related code as no drivers is using it.

[Daniel: Fixed the description]

Fixes: dc11bae785295 ("clocksource/drivers: Add timer-of common init routine")
Reported-by: Uros Bizjak &lt;ubizjak@gmail.com&gt;
Tested-by: Uros Bizjak &lt;ubizjak@gmail.com&gt;
Link: https://lore.kernel.org/r/20240819100335.2394751-1-daniel.lezcano@linaro.org
Signed-off-by: Daniel Lezcano &lt;daniel.lezcano@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 471ef0b5a8aaca4296108e756b970acfc499ede4 upstream.

GCC's named address space checks errors out with:

drivers/clocksource/timer-of.c: In function ‘timer_of_irq_exit’:
drivers/clocksource/timer-of.c:29:46: error: passing argument 2 of
‘free_percpu_irq’ from pointer to non-enclosed address space
  29 |                 free_percpu_irq(of_irq-&gt;irq, clkevt);
     |                                              ^~~~~~
In file included from drivers/clocksource/timer-of.c:8:
./include/linux/interrupt.h:201:43: note: expected ‘__seg_gs void *’
but argument is of type ‘struct clock_event_device *’
 201 | extern void free_percpu_irq(unsigned int, void __percpu *);
     |                                           ^~~~~~~~~~~~~~~
drivers/clocksource/timer-of.c: In function ‘timer_of_irq_init’:
drivers/clocksource/timer-of.c:74:51: error: passing argument 4 of
‘request_percpu_irq’ from pointer to non-enclosed address space
  74 |                                    np-&gt;full_name, clkevt) :
     |                                                   ^~~~~~
./include/linux/interrupt.h:190:56: note: expected ‘__seg_gs void *’
but argument is of type ‘struct clock_event_device *’
 190 |                    const char *devname, void __percpu *percpu_dev_id)

Sparse warns about:

timer-of.c:29:46: warning: incorrect type in argument 2 (different address spaces)
timer-of.c:29:46:    expected void [noderef] __percpu *
timer-of.c:29:46:    got struct clock_event_device *clkevt
timer-of.c:74:51: warning: incorrect type in argument 4 (different address spaces)
timer-of.c:74:51:    expected void [noderef] __percpu *percpu_dev_id
timer-of.c:74:51:    got struct clock_event_device *clkevt

It appears the code is incorrect as reported by Uros Bizjak:

"The referred code is questionable as it tries to reuse
the clkevent pointer once as percpu pointer and once as generic
pointer, which should be avoided."

This change removes the percpu related code as no drivers is using it.

[Daniel: Fixed the description]

Fixes: dc11bae785295 ("clocksource/drivers: Add timer-of common init routine")
Reported-by: Uros Bizjak &lt;ubizjak@gmail.com&gt;
Tested-by: Uros Bizjak &lt;ubizjak@gmail.com&gt;
Link: https://lore.kernel.org/r/20240819100335.2394751-1-daniel.lezcano@linaro.org
Signed-off-by: Daniel Lezcano &lt;daniel.lezcano@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>clocksource/drivers/imx-tpm: Fix next event not taking effect sometime</title>
<updated>2024-09-12T09:13:07+00:00</updated>
<author>
<name>Jacky Bai</name>
<email>ping.bai@nxp.com</email>
</author>
<published>2024-07-25T19:33:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=9c09812e885ac93555540774b679aa8a912df890'/>
<id>9c09812e885ac93555540774b679aa8a912df890</id>
<content type='text'>
commit 3d5c2f8e75a55cfb11a85086c71996af0354a1fb upstream.

The value written into the TPM CnV can only be updated into the hardware
when the counter increases. Additional writes to the CnV write buffer are
ignored until the register has been updated. Therefore, we need to check
if the CnV has been updated before continuing. This may require waiting for
1 counter cycle in the worst case.

Cc: stable@vger.kernel.org
Fixes: 059ab7b82eec ("clocksource/drivers/imx-tpm: Add imx tpm timer support")
Signed-off-by: Jacky Bai &lt;ping.bai@nxp.com&gt;
Reviewed-by: Peng Fan &lt;peng.fan@nxp.com&gt;
Reviewed-by: Ye Li &lt;ye.li@nxp.com&gt;
Reviewed-by: Jason Liu &lt;jason.hui.liu@nxp.com&gt;
Signed-off-by: Frank Li &lt;Frank.Li@nxp.com&gt;
Link: https://lore.kernel.org/r/20240725193355.1436005-2-Frank.Li@nxp.com
Signed-off-by: Daniel Lezcano &lt;daniel.lezcano@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 3d5c2f8e75a55cfb11a85086c71996af0354a1fb upstream.

The value written into the TPM CnV can only be updated into the hardware
when the counter increases. Additional writes to the CnV write buffer are
ignored until the register has been updated. Therefore, we need to check
if the CnV has been updated before continuing. This may require waiting for
1 counter cycle in the worst case.

Cc: stable@vger.kernel.org
Fixes: 059ab7b82eec ("clocksource/drivers/imx-tpm: Add imx tpm timer support")
Signed-off-by: Jacky Bai &lt;ping.bai@nxp.com&gt;
Reviewed-by: Peng Fan &lt;peng.fan@nxp.com&gt;
Reviewed-by: Ye Li &lt;ye.li@nxp.com&gt;
Reviewed-by: Jason Liu &lt;jason.hui.liu@nxp.com&gt;
Signed-off-by: Frank Li &lt;Frank.Li@nxp.com&gt;
Link: https://lore.kernel.org/r/20240725193355.1436005-2-Frank.Li@nxp.com
Signed-off-by: Daniel Lezcano &lt;daniel.lezcano@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>clocksource/drivers/imx-tpm: Fix return -ETIME when delta exceeds INT_MAX</title>
<updated>2024-09-12T09:13:07+00:00</updated>
<author>
<name>Jacky Bai</name>
<email>ping.bai@nxp.com</email>
</author>
<published>2024-07-25T19:33:54+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=13145027070c86aee74e73a029afe8394773a0fc'/>
<id>13145027070c86aee74e73a029afe8394773a0fc</id>
<content type='text'>
commit 5b8843fcd49827813da80c0f590a17ae4ce93c5d upstream.

In tpm_set_next_event(delta), return -ETIME by wrong cast to int when delta
is larger than INT_MAX.

For example:

tpm_set_next_event(delta = 0xffff_fffe)
{
        ...
        next = tpm_read_counter(); // assume next is 0x10
        next += delta; // next will 0xffff_fffe + 0x10 = 0x1_0000_000e
        now = tpm_read_counter();  // now is 0x10
        ...

        return (int)(next - now) &lt;= 0 ? -ETIME : 0;
                     ^^^^^^^^^^
                     0x1_0000_000e - 0x10 = 0xffff_fffe, which is -2 when
                     cast to int. So return -ETIME.
}

To fix this, introduce a 'prev' variable and check if 'now - prev' is
larger than delta.

Cc: stable@vger.kernel.org
Fixes: 059ab7b82eec ("clocksource/drivers/imx-tpm: Add imx tpm timer support")
Signed-off-by: Jacky Bai &lt;ping.bai@nxp.com&gt;
Reviewed-by: Peng Fan &lt;peng.fan@nxp.com&gt;
Reviewed-by: Ye Li &lt;ye.li@nxp.com&gt;
Reviewed-by: Jason Liu &lt;jason.hui.liu@nxp.com&gt;
Signed-off-by: Frank Li &lt;Frank.Li@nxp.com&gt;
Link: https://lore.kernel.org/r/20240725193355.1436005-1-Frank.Li@nxp.com
Signed-off-by: Daniel Lezcano &lt;daniel.lezcano@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 5b8843fcd49827813da80c0f590a17ae4ce93c5d upstream.

In tpm_set_next_event(delta), return -ETIME by wrong cast to int when delta
is larger than INT_MAX.

For example:

tpm_set_next_event(delta = 0xffff_fffe)
{
        ...
        next = tpm_read_counter(); // assume next is 0x10
        next += delta; // next will 0xffff_fffe + 0x10 = 0x1_0000_000e
        now = tpm_read_counter();  // now is 0x10
        ...

        return (int)(next - now) &lt;= 0 ? -ETIME : 0;
                     ^^^^^^^^^^
                     0x1_0000_000e - 0x10 = 0xffff_fffe, which is -2 when
                     cast to int. So return -ETIME.
}

To fix this, introduce a 'prev' variable and check if 'now - prev' is
larger than delta.

Cc: stable@vger.kernel.org
Fixes: 059ab7b82eec ("clocksource/drivers/imx-tpm: Add imx tpm timer support")
Signed-off-by: Jacky Bai &lt;ping.bai@nxp.com&gt;
Reviewed-by: Peng Fan &lt;peng.fan@nxp.com&gt;
Reviewed-by: Ye Li &lt;ye.li@nxp.com&gt;
Reviewed-by: Jason Liu &lt;jason.hui.liu@nxp.com&gt;
Signed-off-by: Frank Li &lt;Frank.Li@nxp.com&gt;
Link: https://lore.kernel.org/r/20240725193355.1436005-1-Frank.Li@nxp.com
Signed-off-by: Daniel Lezcano &lt;daniel.lezcano@linaro.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>clocksource/drivers/sh_cmt: Address race condition for clock events</title>
<updated>2024-08-14T13:34:07+00:00</updated>
<author>
<name>Niklas Söderlund</name>
<email>niklas.soderlund+renesas@ragnatech.se</email>
</author>
<published>2024-07-02T19:02:30+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=417a820de0255cb2e2219a878a0144a65081e2e2'/>
<id>417a820de0255cb2e2219a878a0144a65081e2e2</id>
<content type='text'>
[ Upstream commit db19d3aa77612983a02bd223b3f273f896b243cf ]

There is a race condition in the CMT interrupt handler. In the interrupt
handler the driver sets a driver private flag, FLAG_IRQCONTEXT. This
flag is used to indicate any call to set_next_event() should not be
directly propagated to the device, but instead cached. This is done as
the interrupt handler itself reprograms the device when needed before it
completes and this avoids this operation to take place twice.

It is unclear why this design was chosen, my suspicion is to allow the
struct clock_event_device.event_handler callback, which is called while
the FLAG_IRQCONTEXT is set, can update the next event without having to
write to the device twice.

Unfortunately there is a race between when the FLAG_IRQCONTEXT flag is
set and later cleared where the interrupt handler have already started to
write the next event to the device. If set_next_event() is called in
this window the value is only cached in the driver but not written. This
leads to the board to misbehave, or worse lockup and produce a splat.

   rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
   rcu:     0-...!: (0 ticks this GP) idle=f5e0/0/0x0 softirq=519/519 fqs=0 (false positive?)
   rcu:     (detected by 1, t=6502 jiffies, g=-595, q=77 ncpus=2)
   Sending NMI from CPU 1 to CPUs 0:
   NMI backtrace for cpu 0
   CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.10.0-rc5-arm64-renesas-00019-g74a6f86eaf1c-dirty #20
   Hardware name: Renesas Salvator-X 2nd version board based on r8a77965 (DT)
   pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
   pc : tick_check_broadcast_expired+0xc/0x40
   lr : cpu_idle_poll.isra.0+0x8c/0x168
   sp : ffff800081c63d70
   x29: ffff800081c63d70 x28: 00000000580000c8 x27: 00000000bfee5610
   x26: 0000000000000027 x25: 0000000000000000 x24: 0000000000000000
   x23: ffff00007fbb9100 x22: ffff8000818f1008 x21: ffff8000800ef07c
   x20: ffff800081c79ec0 x19: ffff800081c70c28 x18: 0000000000000000
   x17: 0000000000000000 x16: 0000000000000000 x15: 0000ffffc2c717d8
   x14: 0000000000000000 x13: ffff000009c18080 x12: ffff8000825f7fc0
   x11: 0000000000000000 x10: ffff8000818f3cd4 x9 : 0000000000000028
   x8 : ffff800081c79ec0 x7 : ffff800081c73000 x6 : 0000000000000000
   x5 : 0000000000000000 x4 : ffff7ffffe286000 x3 : 0000000000000000
   x2 : ffff7ffffe286000 x1 : ffff800082972900 x0 : ffff8000818f1008
   Call trace:
    tick_check_broadcast_expired+0xc/0x40
    do_idle+0x9c/0x280
    cpu_startup_entry+0x34/0x40
    kernel_init+0x0/0x11c
    do_one_initcall+0x0/0x260
    __primary_switched+0x80/0x88
   rcu: rcu_preempt kthread timer wakeup didn't happen for 6501 jiffies! g-595 f0x0 RCU_GP_WAIT_FQS(5) -&gt;state=0x402
   rcu:     Possible timer handling issue on cpu=0 timer-softirq=262
   rcu: rcu_preempt kthread starved for 6502 jiffies! g-595 f0x0 RCU_GP_WAIT_FQS(5) -&gt;state=0x402 -&gt;cpu=0
   rcu:     Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
   rcu: RCU grace-period kthread stack dump:
   task:rcu_preempt     state:I stack:0     pid:15    tgid:15    ppid:2      flags:0x00000008
   Call trace:
    __switch_to+0xbc/0x100
    __schedule+0x358/0xbe0
    schedule+0x48/0x148
    schedule_timeout+0xc4/0x138
    rcu_gp_fqs_loop+0x12c/0x764
    rcu_gp_kthread+0x208/0x298
    kthread+0x10c/0x110
    ret_from_fork+0x10/0x20

The design have been part of the driver since it was first merged in
early 2009. It becomes increasingly harder to trigger the issue the
older kernel version one tries. It only takes a few boots on v6.10-rc5,
while hundreds of boots are needed to trigger it on v5.10.

Close the race condition by using the CMT channel lock for the two
competing sections. The channel lock was added to the driver after its
initial design.

Signed-off-by: Niklas Söderlund &lt;niklas.soderlund+renesas@ragnatech.se&gt;
Link: https://lore.kernel.org/r/20240702190230.3825292-1-niklas.soderlund+renesas@ragnatech.se
Signed-off-by: Daniel Lezcano &lt;daniel.lezcano@linaro.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit db19d3aa77612983a02bd223b3f273f896b243cf ]

There is a race condition in the CMT interrupt handler. In the interrupt
handler the driver sets a driver private flag, FLAG_IRQCONTEXT. This
flag is used to indicate any call to set_next_event() should not be
directly propagated to the device, but instead cached. This is done as
the interrupt handler itself reprograms the device when needed before it
completes and this avoids this operation to take place twice.

It is unclear why this design was chosen, my suspicion is to allow the
struct clock_event_device.event_handler callback, which is called while
the FLAG_IRQCONTEXT is set, can update the next event without having to
write to the device twice.

Unfortunately there is a race between when the FLAG_IRQCONTEXT flag is
set and later cleared where the interrupt handler have already started to
write the next event to the device. If set_next_event() is called in
this window the value is only cached in the driver but not written. This
leads to the board to misbehave, or worse lockup and produce a splat.

   rcu: INFO: rcu_preempt detected stalls on CPUs/tasks:
   rcu:     0-...!: (0 ticks this GP) idle=f5e0/0/0x0 softirq=519/519 fqs=0 (false positive?)
   rcu:     (detected by 1, t=6502 jiffies, g=-595, q=77 ncpus=2)
   Sending NMI from CPU 1 to CPUs 0:
   NMI backtrace for cpu 0
   CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.10.0-rc5-arm64-renesas-00019-g74a6f86eaf1c-dirty #20
   Hardware name: Renesas Salvator-X 2nd version board based on r8a77965 (DT)
   pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
   pc : tick_check_broadcast_expired+0xc/0x40
   lr : cpu_idle_poll.isra.0+0x8c/0x168
   sp : ffff800081c63d70
   x29: ffff800081c63d70 x28: 00000000580000c8 x27: 00000000bfee5610
   x26: 0000000000000027 x25: 0000000000000000 x24: 0000000000000000
   x23: ffff00007fbb9100 x22: ffff8000818f1008 x21: ffff8000800ef07c
   x20: ffff800081c79ec0 x19: ffff800081c70c28 x18: 0000000000000000
   x17: 0000000000000000 x16: 0000000000000000 x15: 0000ffffc2c717d8
   x14: 0000000000000000 x13: ffff000009c18080 x12: ffff8000825f7fc0
   x11: 0000000000000000 x10: ffff8000818f3cd4 x9 : 0000000000000028
   x8 : ffff800081c79ec0 x7 : ffff800081c73000 x6 : 0000000000000000
   x5 : 0000000000000000 x4 : ffff7ffffe286000 x3 : 0000000000000000
   x2 : ffff7ffffe286000 x1 : ffff800082972900 x0 : ffff8000818f1008
   Call trace:
    tick_check_broadcast_expired+0xc/0x40
    do_idle+0x9c/0x280
    cpu_startup_entry+0x34/0x40
    kernel_init+0x0/0x11c
    do_one_initcall+0x0/0x260
    __primary_switched+0x80/0x88
   rcu: rcu_preempt kthread timer wakeup didn't happen for 6501 jiffies! g-595 f0x0 RCU_GP_WAIT_FQS(5) -&gt;state=0x402
   rcu:     Possible timer handling issue on cpu=0 timer-softirq=262
   rcu: rcu_preempt kthread starved for 6502 jiffies! g-595 f0x0 RCU_GP_WAIT_FQS(5) -&gt;state=0x402 -&gt;cpu=0
   rcu:     Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior.
   rcu: RCU grace-period kthread stack dump:
   task:rcu_preempt     state:I stack:0     pid:15    tgid:15    ppid:2      flags:0x00000008
   Call trace:
    __switch_to+0xbc/0x100
    __schedule+0x358/0xbe0
    schedule+0x48/0x148
    schedule_timeout+0xc4/0x138
    rcu_gp_fqs_loop+0x12c/0x764
    rcu_gp_kthread+0x208/0x298
    kthread+0x10c/0x110
    ret_from_fork+0x10/0x20

The design have been part of the driver since it was first merged in
early 2009. It becomes increasingly harder to trigger the issue the
older kernel version one tries. It only takes a few boots on v6.10-rc5,
while hundreds of boots are needed to trigger it on v5.10.

Close the race condition by using the CMT channel lock for the two
competing sections. The channel lock was added to the driver after its
initial design.

Signed-off-by: Niklas Söderlund &lt;niklas.soderlund+renesas@ragnatech.se&gt;
Link: https://lore.kernel.org/r/20240702190230.3825292-1-niklas.soderlund+renesas@ragnatech.se
Signed-off-by: Daniel Lezcano &lt;daniel.lezcano@linaro.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'riscv-for-linus-6.10-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux</title>
<updated>2024-05-22T16:56:00+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2024-05-22T16:56:00+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=0bfbc914d9433d8ac2763a9ce99ce7721ee5c8e0'/>
<id>0bfbc914d9433d8ac2763a9ce99ce7721ee5c8e0</id>
<content type='text'>
Pull RISC-V updates from Palmer Dabbelt:

 - Add byte/half-word compare-and-exchange, emulated via LR/SC loops

 - Support for Rust

 - Support for Zihintpause in hwprobe

 - Add PR_RISCV_SET_ICACHE_FLUSH_CTX prctl()

 - Support lockless lockrefs

* tag 'riscv-for-linus-6.10-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (42 commits)
  riscv: defconfig: Enable CONFIG_CLK_SOPHGO_CV1800
  riscv: select ARCH_HAS_FAST_MULTIPLIER
  riscv: mm: still create swiotlb buffer for kmalloc() bouncing if required
  riscv: Annotate pgtable_l{4,5}_enabled with __ro_after_init
  riscv: Remove redundant CONFIG_64BIT from pgtable_l{4,5}_enabled
  riscv: mm: Always use an ASID to flush mm contexts
  riscv: mm: Preserve global TLB entries when switching contexts
  riscv: mm: Make asid_bits a local variable
  riscv: mm: Use a fixed layout for the MM context ID
  riscv: mm: Introduce cntx2asid/cntx2version helper macros
  riscv: Avoid TLB flush loops when affected by SiFive CIP-1200
  riscv: Apply SiFive CIP-1200 workaround to single-ASID sfence.vma
  riscv: mm: Combine the SMP and UP TLB flush code
  riscv: Only send remote fences when some other CPU is online
  riscv: mm: Broadcast kernel TLB flushes only when needed
  riscv: Use IPIs for remote cache/TLB flushes by default
  riscv: Factor out page table TLB synchronization
  riscv: Flush the instruction cache during SMP bringup
  riscv: hwprobe: export Zihintpause ISA extension
  riscv: misaligned: remove CONFIG_RISCV_M_MODE specific code
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull RISC-V updates from Palmer Dabbelt:

 - Add byte/half-word compare-and-exchange, emulated via LR/SC loops

 - Support for Rust

 - Support for Zihintpause in hwprobe

 - Add PR_RISCV_SET_ICACHE_FLUSH_CTX prctl()

 - Support lockless lockrefs

* tag 'riscv-for-linus-6.10-mw1' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (42 commits)
  riscv: defconfig: Enable CONFIG_CLK_SOPHGO_CV1800
  riscv: select ARCH_HAS_FAST_MULTIPLIER
  riscv: mm: still create swiotlb buffer for kmalloc() bouncing if required
  riscv: Annotate pgtable_l{4,5}_enabled with __ro_after_init
  riscv: Remove redundant CONFIG_64BIT from pgtable_l{4,5}_enabled
  riscv: mm: Always use an ASID to flush mm contexts
  riscv: mm: Preserve global TLB entries when switching contexts
  riscv: mm: Make asid_bits a local variable
  riscv: mm: Use a fixed layout for the MM context ID
  riscv: mm: Introduce cntx2asid/cntx2version helper macros
  riscv: Avoid TLB flush loops when affected by SiFive CIP-1200
  riscv: Apply SiFive CIP-1200 workaround to single-ASID sfence.vma
  riscv: mm: Combine the SMP and UP TLB flush code
  riscv: Only send remote fences when some other CPU is online
  riscv: mm: Broadcast kernel TLB flushes only when needed
  riscv: Use IPIs for remote cache/TLB flushes by default
  riscv: Factor out page table TLB synchronization
  riscv: Flush the instruction cache during SMP bringup
  riscv: hwprobe: export Zihintpause ISA extension
  riscv: misaligned: remove CONFIG_RISCV_M_MODE specific code
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>clocksource/drivers/arm_arch_timer: Mark hisi_161010101_oem_info const</title>
<updated>2024-05-10T08:43:21+00:00</updated>
<author>
<name>Stephen Boyd</name>
<email>swboyd@chromium.org</email>
</author>
<published>2024-05-02T23:34:46+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=2030a7e11f161b4067bd4eadd984cdb36446fcca'/>
<id>2030a7e11f161b4067bd4eadd984cdb36446fcca</id>
<content type='text'>
This isn't modified at runtime. Mark it const so it can move to
read-only data.

Cc: dann frazier &lt;dann.frazier@canonical.com&gt;
Cc: Hanjun Guo &lt;hanjun.guo@linaro.org&gt;
Cc: Marc Zyngier &lt;maz@kernel.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Signed-off-by: Stephen Boyd &lt;swboyd@chromium.org&gt;
Reviewed-by: Hanjun Guo &lt;guohanjun@huawei.com&gt;
Signed-off-by: Daniel Lezcano &lt;daniel.lezcano@linaro.org&gt;
Link: https://lore.kernel.org/r/20240502233447.420888-1-swboyd@chromium.org
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This isn't modified at runtime. Mark it const so it can move to
read-only data.

Cc: dann frazier &lt;dann.frazier@canonical.com&gt;
Cc: Hanjun Guo &lt;hanjun.guo@linaro.org&gt;
Cc: Marc Zyngier &lt;maz@kernel.org&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Signed-off-by: Stephen Boyd &lt;swboyd@chromium.org&gt;
Reviewed-by: Hanjun Guo &lt;guohanjun@huawei.com&gt;
Signed-off-by: Daniel Lezcano &lt;daniel.lezcano@linaro.org&gt;
Link: https://lore.kernel.org/r/20240502233447.420888-1-swboyd@chromium.org
</pre>
</div>
</content>
</entry>
<entry>
<title>clocksource/drivers/timer-ti-dm: Remove an unused field in struct dmtimer</title>
<updated>2024-05-10T08:41:52+00:00</updated>
<author>
<name>Christophe JAILLET</name>
<email>christophe.jaillet@wanadoo.fr</email>
</author>
<published>2024-04-30T21:42:39+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=e6f8bed209d5fa8602cda45930b0a331234d95ed'/>
<id>e6f8bed209d5fa8602cda45930b0a331234d95ed</id>
<content type='text'>
In "struct dmtimer", the 'rate' field is unused.
Remove it.

Found with cppcheck, unusedStructMember.

Signed-off-by: Christophe JAILLET &lt;christophe.jaillet@wanadoo.fr&gt;
Signed-off-by: Daniel Lezcano &lt;daniel.lezcano@linaro.org&gt;
Link: https://lore.kernel.org/r/c9f7579922c587fce334a1aa9651f3189de7a00b.1714513336.git.christophe.jaillet@wanadoo.fr
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
In "struct dmtimer", the 'rate' field is unused.
Remove it.

Found with cppcheck, unusedStructMember.

Signed-off-by: Christophe JAILLET &lt;christophe.jaillet@wanadoo.fr&gt;
Signed-off-by: Daniel Lezcano &lt;daniel.lezcano@linaro.org&gt;
Link: https://lore.kernel.org/r/c9f7579922c587fce334a1aa9651f3189de7a00b.1714513336.git.christophe.jaillet@wanadoo.fr
</pre>
</div>
</content>
</entry>
<entry>
<title>clocksource/drivers/renesas-ostm: Avoid reprobe after successful early probe</title>
<updated>2024-05-10T08:41:52+00:00</updated>
<author>
<name>Geert Uytterhoeven</name>
<email>geert+renesas@glider.be</email>
</author>
<published>2024-03-20T10:30:07+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=37385c0772a4fc6b89605b9701fa934fa2beb2cc'/>
<id>37385c0772a4fc6b89605b9701fa934fa2beb2cc</id>
<content type='text'>
The Renesas OS Timer (OSTM) driver contains two probe points, of which
only one should complete:
  1. Early probe, using TIMER_OF_DECLARE(), to provide the sole
     clocksource on (arm32) RZ/A1 and RZ/A2 SoCs,
  2. Normal probe, using a platform driver, to provide additional timers
     on (arm64 + riscv) RZ/G2L and similar SoCs.

The latter is needed because using OSTM on RZ/G2L requires manipulation
of its reset signal, which is not yet available at the time of early
probe, causing early probe to fail with -EPROBE_DEFER.  It is only
enabled when building a kernel with support for the RZ/G2L family, so it
does not impact RZ/A1 and RZ/A2.  Hence only one probe method can
complete on all affected systems.

As relying on the order of initialization of subsystems inside the
kernel is fragile, set the DT node's OF_POPULATED flag after a succesful
early probe.  This makes sure the platform driver's probe is never
called after a successful early probe.

Signed-off-by: Geert Uytterhoeven &lt;geert+renesas@glider.be&gt;
Reviwed-by: Lad Prabhakar &lt;prabhakar.mahadev-lad.rj@bp.renesas.com&gt;
Signed-off-by: Daniel Lezcano &lt;daniel.lezcano@linaro.org&gt;
Link: https://lore.kernel.org/r/bd027379713cbaafa21ffe9e848ebb7f475ca0e7.1710930542.git.geert+renesas@glider.be
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The Renesas OS Timer (OSTM) driver contains two probe points, of which
only one should complete:
  1. Early probe, using TIMER_OF_DECLARE(), to provide the sole
     clocksource on (arm32) RZ/A1 and RZ/A2 SoCs,
  2. Normal probe, using a platform driver, to provide additional timers
     on (arm64 + riscv) RZ/G2L and similar SoCs.

The latter is needed because using OSTM on RZ/G2L requires manipulation
of its reset signal, which is not yet available at the time of early
probe, causing early probe to fail with -EPROBE_DEFER.  It is only
enabled when building a kernel with support for the RZ/G2L family, so it
does not impact RZ/A1 and RZ/A2.  Hence only one probe method can
complete on all affected systems.

As relying on the order of initialization of subsystems inside the
kernel is fragile, set the DT node's OF_POPULATED flag after a succesful
early probe.  This makes sure the platform driver's probe is never
called after a successful early probe.

Signed-off-by: Geert Uytterhoeven &lt;geert+renesas@glider.be&gt;
Reviwed-by: Lad Prabhakar &lt;prabhakar.mahadev-lad.rj@bp.renesas.com&gt;
Signed-off-by: Daniel Lezcano &lt;daniel.lezcano@linaro.org&gt;
Link: https://lore.kernel.org/r/bd027379713cbaafa21ffe9e848ebb7f475ca0e7.1710930542.git.geert+renesas@glider.be
</pre>
</div>
</content>
</entry>
</feed>
