Hi, experts:
Linaro has released a 64bit kernel for ARMv8 FVP model.
So, how to compile it to Aarch32 bin?
I want to try to change boot wrapper code to switch to Aarch32 EL1
before jumping to kernel entrypoint.
So, I need to compile linux kernel to Aarch32 bin.
Best wishes,
Hi Frederic,
File: kernel/time/tick-sched.c
Function: tick_nohz_full_stop_tick()
We are doing this:
if (!tick_nohz_full_cpu(cpu) || is_idle_task(current))
return;
Which means: if a FULL_NO_HZ cpu is running idle task currently,
don't stop its tick..
I couldn't understand why. Can you please help here?
--
viresh
From: Chander Kashyap <k.chander(a)samsung.com>
We don't have any protection against addition of duplicate OPPs currently and in
case some code tries to add them, it will end up corrupting OPP tables.
We need to handle some duplication cases separately as returning error might not
be the right thing always. The new list of return values for dev_pm_opp_add()
are:
0: On success OR
Duplicate OPPs (both freq and volt are same) and opp->available
-EEXIST: Freq are same and volt are different OR
Duplicate OPPs (both freq and volt are same) and !opp->available
-ENOMEM: Memory allocation failure
Acked-by: Nishanth Menon <nm(a)ti.com>
Signed-off-by: Chander Kashyap <k.chander(a)samsung.com>
Signed-off-by: Inderpal Singh <inderpal.s(a)samsung.com>
Signed-off-by: Viresh Kumar <viresh.kumar(a)linaro.org>
---
I took some rest before sending V6, just to make sure I don't send another
version in hurry with any obvious mistake.
V5->V6:
- Remove parenthesis around initialization of 'ret'.
- s/Returns/Return
- Fix checkpatch.pl --strict warning: 'Alignment should match open parenthesis'
- Tried improving changelog..
drivers/base/power/opp.c | 27 +++++++++++++++++++++++++--
1 file changed, 25 insertions(+), 2 deletions(-)
diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
index faae9cf..89ced95 100644
--- a/drivers/base/power/opp.c
+++ b/drivers/base/power/opp.c
@@ -393,6 +393,13 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_floor);
* to keep the integrity of the internal data structures. Callers should ensure
* that this function is *NOT* called under RCU protection or in contexts where
* mutex cannot be locked.
+ *
+ * Return:
+ * 0: On success OR
+ * Duplicate OPPs (both freq and volt are same) and opp->available
+ * -EEXIST: Freq are same and volt are different OR
+ * Duplicate OPPs (both freq and volt are same) and !opp->available
+ * -ENOMEM: Memory allocation failure
*/
int dev_pm_opp_add(struct device *dev, unsigned long freq, unsigned long u_volt)
{
@@ -442,15 +449,31 @@ int dev_pm_opp_add(struct device *dev, unsigned long freq, unsigned long u_volt)
new_opp->u_volt = u_volt;
new_opp->available = true;
- /* Insert new OPP in order of increasing frequency */
+ /*
+ * Insert new OPP in order of increasing frequency
+ * and discard if already present
+ */
head = &dev_opp->opp_list;
list_for_each_entry_rcu(opp, &dev_opp->opp_list, node) {
- if (new_opp->rate < opp->rate)
+ if (new_opp->rate <= opp->rate)
break;
else
head = &opp->node;
}
+ /* Duplicate OPPs ? */
+ if (new_opp->rate == opp->rate) {
+ int ret = opp->available && new_opp->u_volt == opp->u_volt ?
+ 0 : -EEXIST;
+
+ dev_warn(dev, "%s: duplicate OPPs detected. Existing: freq: %lu, volt: %lu, enabled: %d. New: freq: %lu, volt: %lu, enabled: %d\n",
+ __func__, opp->rate, opp->u_volt, opp->available,
+ new_opp->rate, new_opp->u_volt, new_opp->available);
+ mutex_unlock(&dev_opp_list_lock);
+ kfree(new_opp);
+ return ret;
+ }
+
list_add_rcu(&new_opp->node, head);
mutex_unlock(&dev_opp_list_lock);
--
2.0.0.rc2
All drivers expecting CPU's OPPs from device tree initialize OPP table using
of_init_opp_table() and there is nothing driver specific in that. They all do it
in the same way adding to code redundancy.
It would be better if we can get rid of code redundancy by initializing CPU OPPs
from core code for all CPUs that have a "operating-points" property defined in
their node.
First patch initializes OPPs as soon as CPU device is registered in
register_cpu(). Following patches get rid of these calls from individual drivers
which are currently initializing OPPs.
The idea was initially discussed here: https://lkml.org/lkml/2014/5/17/123
Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
Cc: Amit Daniel Kachhap <amit.daniel(a)samsung.com>
Cc: Kukjin Kim <kgene.kim(a)samsung.com>
Cc: Shawn Guo <shawn.guo(a)linaro.org>
Cc: Sudeep Holla <sudeep.holla(a)arm.com>
Viresh Kumar (5):
driver/core: cpu: initialize opp table
cpufreq: arm_big_little: don't initialize opp table
cpufreq: imx6q: don't initialize opp table
cpufreq: cpufreq-cpu0: don't initialize opp table
cpufreq: exynos5440: don't initialize opp table
arch/arm/mach-imx/mach-imx6q.c | 36 ++++++++----------------------------
drivers/base/cpu.c | 14 ++++++++++++--
drivers/cpufreq/arm_big_little.c | 12 +++++++-----
drivers/cpufreq/arm_big_little_dt.c | 18 ------------------
drivers/cpufreq/cpufreq-cpu0.c | 6 ------
drivers/cpufreq/exynos5440-cpufreq.c | 6 ------
drivers/cpufreq/imx6q-cpufreq.c | 20 +-------------------
7 files changed, 28 insertions(+), 84 deletions(-)
--
2.0.0.rc2
This is second attempt to initialize CPU's OPPs from CPU core code. First one
was here: https://lkml.org/lkml/2014/5/19/57
All drivers expecting CPU's OPPs from device tree initialize OPP table using
of_init_opp_table() and there is nothing driver specific in that. They all do it
in the same way adding to code redundancy.
It would be better if we can get rid of code redundancy by initializing CPU OPPs
from core code for all CPUs that have a "operating-points" property defined in
their node.
This patchset is all about that.
The idea was initially discussed here: https://lkml.org/lkml/2014/5/17/123
V1->V2:
- Addition of two new patches: 1/2 & 2/2
- Created separate routine of_init_cpu_opp_table() which wouldn't add any
overhead for the platforms which don't have OPP or OF enabled.
- Added a print for success case as well
- Added Acks from Shawn
- Got rid of extra indentation level by returning early from register_cpu().
Cc: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org>
Cc: Amit Daniel Kachhap <amit.daniel(a)samsung.com>
Cc: Kukjin Kim <kgene.kim(a)samsung.com>
Cc: Shawn Guo <shawn.guo(a)linaro.org>
Viresh Kumar (7):
opp: remove -ENOSYS from dummy implementation of of_init_opp_table()
opp: handle of_node_{get|put}() inside of_init_opp_table()
driver/core: cpu: initialize opp table
cpufreq: arm_big_little: don't initialize opp table
cpufreq: imx6q: don't initialize opp table
cpufreq: cpufreq-cpu0: don't initialize opp table
cpufreq: exynos5440: don't initialize opp table
arch/arm/mach-imx/mach-imx6q.c | 36 ++++++++----------------------------
drivers/base/cpu.c | 30 ++++++++++++++++++++++++++----
drivers/base/power/opp.c | 4 ++++
drivers/cpufreq/arm_big_little.c | 12 +++++++-----
drivers/cpufreq/arm_big_little_dt.c | 18 ------------------
drivers/cpufreq/cpufreq-cpu0.c | 6 ------
drivers/cpufreq/exynos5440-cpufreq.c | 6 ------
drivers/cpufreq/imx6q-cpufreq.c | 20 +-------------------
include/linux/pm_opp.h | 2 +-
9 files changed, 47 insertions(+), 87 deletions(-)
--
2.0.0.rc2
From: Chander Kashyap <k.chander(a)samsung.com>
We don't have any protection against addition of duplicate OPPs currently and
in case some code tries to add them it will end up corrupting OPP tables.
There can be many combinations in which we may end up trying duplicate OPPs:
- both freq and volt are same, but earlier OPP may or may not be active.
- only freq is same and volt is different.
This patch tries to implement below logic for these cases:
Return 0 if new OPP was duplicate of existing one (i.e. same freq and volt) and
return -EEXIST if new OPP had same freq but different volt as of an existing OPP
OR if both freq/volt were same but earlier OPP was disabled.
Signed-off-by: Chander Kashyap <k.chander(a)samsung.com>
Signed-off-by: Inderpal Singh <inderpal.s(a)samsung.com>
Signed-off-by: Viresh Kumar <viresh.kumar(a)linaro.org>
---
V4->V5:
- Mention Return values under 'Return:' clause of doc style comment.
- s/pr_warn/dev_warn
- s/linrao/linaro in my email id :(
drivers/base/power/opp.c | 27 +++++++++++++++++++++++++--
1 file changed, 25 insertions(+), 2 deletions(-)
diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
index 2553867..6a06d43 100644
--- a/drivers/base/power/opp.c
+++ b/drivers/base/power/opp.c
@@ -394,6 +394,13 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_floor);
* to keep the integrity of the internal data structures. Callers should ensure
* that this function is *NOT* called under RCU protection or in contexts where
* mutex cannot be locked.
+ *
+ * Returns:
+ * 0: On success OR
+ * Duplicate OPPs (both freq and volt are same) and opp->available
+ * -EEXIST: Freq are same and volt are different OR
+ * Duplicate OPPs (both freq and volt are same) and !opp->available
+ * -ENOMEM: Memory allocation failure
*/
int dev_pm_opp_add(struct device *dev, unsigned long freq, unsigned long u_volt)
{
@@ -443,15 +450,31 @@ int dev_pm_opp_add(struct device *dev, unsigned long freq, unsigned long u_volt)
new_opp->u_volt = u_volt;
new_opp->available = true;
- /* Insert new OPP in order of increasing frequency */
+ /*
+ * Insert new OPP in order of increasing frequency
+ * and discard if already present
+ */
head = &dev_opp->opp_list;
list_for_each_entry_rcu(opp, &dev_opp->opp_list, node) {
- if (new_opp->rate < opp->rate)
+ if (new_opp->rate <= opp->rate)
break;
else
head = &opp->node;
}
+ /* Duplicate OPPs ? */
+ if (new_opp->rate == opp->rate) {
+ int ret = (new_opp->u_volt == opp->u_volt) && opp->available ?
+ 0 : -EEXIST;
+
+ dev_warn(dev, "%s: duplicate OPPs detected. Existing: freq: %lu, volt: %lu, enabled: %d. New: freq: %lu, volt: %lu, enabled: %d\n",
+ __func__, opp->rate, opp->u_volt, opp->available,
+ new_opp->rate, new_opp->u_volt, new_opp->available);
+ mutex_unlock(&dev_opp_list_lock);
+ kfree(new_opp);
+ return ret;
+ }
+
list_add_rcu(&new_opp->node, head);
mutex_unlock(&dev_opp_list_lock);
--
2.0.0.rc2
