Debugfs is nice and so are module parameters, but
* debugfs doesn't take effect early (e.g., if drivers are locking up
before user space gets anywhere)
* module parameters either add a lot to the kernel command line, or
else take effect late as well (if you build =m and configure in
/etc/modprobe.d/)
So in the same spirit as these
CONFIG_PANIC_ON_OOPS (also available via cmdline or modparam)
CONFIG_INTEL_IOMMU_DEFAULT_ON (also available via cmdline)
add a new Kconfig option.
Module parameters and debugfs can still override.
Signed-off-by: Brian Norris <[email protected]>
---
drivers/hwtracing/coresight/Kconfig | 13 +++++++++++++
drivers/hwtracing/coresight/coresight-cpu-debug.c | 2 +-
2 files changed, 14 insertions(+), 1 deletion(-)
diff --git a/drivers/hwtracing/coresight/Kconfig b/drivers/hwtracing/coresight/Kconfig
index f026e5c0e777..8b638eb3cb7d 100644
--- a/drivers/hwtracing/coresight/Kconfig
+++ b/drivers/hwtracing/coresight/Kconfig
@@ -150,6 +150,19 @@ config CORESIGHT_CPU_DEBUG
To compile this driver as a module, choose M here: the
module will be called coresight-cpu-debug.
+config CORESIGHT_CPU_DEBUG_DEFAULT_ON
+ bool "Enable CoreSight CPU Debug by default
+ depends on CORESIGHT_CPU_DEBUG
+ help
+ Say Y here to enable the CoreSight Debug panic-debug by default. This
+ can also be enabled via debugfs, but this ensures the debug feature
+ is enabled as early as possible.
+
+ Has the same effect as setting coresight_cpu_debug.enable=1 on the
+ kernel command line.
+
+ Say N if unsure.
+
config CORESIGHT_CTI
tristate "CoreSight Cross Trigger Interface (CTI) driver"
depends on ARM || ARM64
diff --git a/drivers/hwtracing/coresight/coresight-cpu-debug.c b/drivers/hwtracing/coresight/coresight-cpu-debug.c
index 00de46565bc4..8845ec4b4402 100644
--- a/drivers/hwtracing/coresight/coresight-cpu-debug.c
+++ b/drivers/hwtracing/coresight/coresight-cpu-debug.c
@@ -105,7 +105,7 @@ static DEFINE_PER_CPU(struct debug_drvdata *, debug_drvdata);
static int debug_count;
static struct dentry *debug_debugfs_dir;
-static bool debug_enable;
+static bool debug_enable = IS_ENABLED(CONFIG_CORESIGHT_CPU_DEBUG_DEFAULT_ON);
module_param_named(enable, debug_enable, bool, 0600);
MODULE_PARM_DESC(enable, "Control to enable coresight CPU debug functionality");
--
2.33.0.153.gba50c8fa24-goog
Hi Brian,
On Fri, Sep 03, 2021 at 06:28:54PM -0700, Brian Norris wrote:
> Debugfs is nice and so are module parameters, but
> * debugfs doesn't take effect early (e.g., if drivers are locking up
> before user space gets anywhere)
> * module parameters either add a lot to the kernel command line, or
> else take effect late as well (if you build =m and configure in
> /etc/modprobe.d/)
>
> So in the same spirit as these
> CONFIG_PANIC_ON_OOPS (also available via cmdline or modparam)
> CONFIG_INTEL_IOMMU_DEFAULT_ON (also available via cmdline)
> add a new Kconfig option.
>
> Module parameters and debugfs can still override.
>
> Signed-off-by: Brian Norris <[email protected]>
> ---
>
> drivers/hwtracing/coresight/Kconfig | 13 +++++++++++++
> drivers/hwtracing/coresight/coresight-cpu-debug.c | 2 +-
> 2 files changed, 14 insertions(+), 1 deletion(-)
>
I have applied this patch to my local tree. I will make that tree public when
next week when 5.15-rc1 has been released.
Thanks,
Mathieu
> diff --git a/drivers/hwtracing/coresight/Kconfig b/drivers/hwtracing/coresight/Kconfig
> index f026e5c0e777..8b638eb3cb7d 100644
> --- a/drivers/hwtracing/coresight/Kconfig
> +++ b/drivers/hwtracing/coresight/Kconfig
> @@ -150,6 +150,19 @@ config CORESIGHT_CPU_DEBUG
> To compile this driver as a module, choose M here: the
> module will be called coresight-cpu-debug.
>
> +config CORESIGHT_CPU_DEBUG_DEFAULT_ON
> + bool "Enable CoreSight CPU Debug by default
> + depends on CORESIGHT_CPU_DEBUG
> + help
> + Say Y here to enable the CoreSight Debug panic-debug by default. This
> + can also be enabled via debugfs, but this ensures the debug feature
> + is enabled as early as possible.
> +
> + Has the same effect as setting coresight_cpu_debug.enable=1 on the
> + kernel command line.
> +
> + Say N if unsure.
> +
> config CORESIGHT_CTI
> tristate "CoreSight Cross Trigger Interface (CTI) driver"
> depends on ARM || ARM64
> diff --git a/drivers/hwtracing/coresight/coresight-cpu-debug.c b/drivers/hwtracing/coresight/coresight-cpu-debug.c
> index 00de46565bc4..8845ec4b4402 100644
> --- a/drivers/hwtracing/coresight/coresight-cpu-debug.c
> +++ b/drivers/hwtracing/coresight/coresight-cpu-debug.c
> @@ -105,7 +105,7 @@ static DEFINE_PER_CPU(struct debug_drvdata *, debug_drvdata);
> static int debug_count;
> static struct dentry *debug_debugfs_dir;
>
> -static bool debug_enable;
> +static bool debug_enable = IS_ENABLED(CONFIG_CORESIGHT_CPU_DEBUG_DEFAULT_ON);
> module_param_named(enable, debug_enable, bool, 0600);
> MODULE_PARM_DESC(enable, "Control to enable coresight CPU debug functionality");
>
> --
> 2.33.0.153.gba50c8fa24-goog
>
On Fri, Sep 3, 2021 at 6:29 PM Brian Norris <[email protected]> wrote:
> --- a/drivers/hwtracing/coresight/Kconfig
> +++ b/drivers/hwtracing/coresight/Kconfig
> @@ -150,6 +150,19 @@ config CORESIGHT_CPU_DEBUG
> +config CORESIGHT_CPU_DEBUG_DEFAULT_ON
> + bool "Enable CoreSight CPU Debug by default
^^ Eek, I failed to terminate this string, and kbuild is even warning about it:
drivers/hwtracing/coresight/Kconfig:145:warning: multi-line strings
not supported
Sorry about that; I can submit a v2 if you'd like, or feel free to fix
up my mistake when you apply it.
Sorry,
Brian
On Wed, Sep 15, 2021 at 4:41 PM Brian Norris <[email protected]> wrote:
>
> On Fri, Sep 3, 2021 at 6:29 PM Brian Norris <[email protected]> wrote:
> > --- a/drivers/hwtracing/coresight/Kconfig
> > +++ b/drivers/hwtracing/coresight/Kconfig
> > @@ -150,6 +150,19 @@ config CORESIGHT_CPU_DEBUG
>
> > +config CORESIGHT_CPU_DEBUG_DEFAULT_ON
> > + bool "Enable CoreSight CPU Debug by default
>
> ^^ Eek, I failed to terminate this string, and kbuild is even warning about it:
>
> drivers/hwtracing/coresight/Kconfig:145:warning: multi-line strings
> not supported
>
> Sorry about that; I can submit a v2 if you'd like, or feel free to fix
> up my mistake when you apply it.
And I see you already fixed it -- should've checked before posting:
https://git.kernel.org/pub/scm/linux/kernel/git/coresight/linux.git/commit/?id=616ac6902c982f03da9d0b1e4f845df0980d055d
[Fixed missing double quote in Kconfig title]
Thanks,
Brian