Re: [GIT PULL] Disintegrate and kill asm/system.h

From: Grant Likely
Date: Thu Mar 29 2012 - 17:01:25 EST


On Thu, 29 Mar 2012 15:14:29 +1100, Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx> wrote:
> On Thu, 2012-03-29 at 13:50 +1100, Michael Neuling wrote:
> > Grant: why does powerpc_debugfs_root appear in generic code? This seems
> > very bogus.
>
> Yes, Grant, you should move that to a different (generic) debugfs file,
> the mapping information is valuable debug data for all architectures
> that use the remapper, not just powerpc and it's not an ABI (no tool I
> know of rely on the location of that debugfs file) so feel free to move
> it around.

I could simply drop the powerpc_debugfs_root argument from
debugfs_create_file() and replace it with NULL. As you say, this is
not an ABI and this will solve the problem.

On Wed, 28 Mar 2012 22:02:41 -0700, Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> Grant - what's the plan about that CONFIG_VIRQ_DEBUG thing? In theory
> something like it could be useful as a generic thing, but at least
> right now it is clearly powerpc-specific (not just that the config
> option only exists for powerpc: it has that whole
> 'powerpc_debugfs_root' thing in it)?
>
> Stephen's patch very much looks like the right thing, but if there was
> some plan to actually make this generic ...

The plan is to make it generic. I just ran out of time for this
cycle to generalize it. I moved all of irqdomain out of arch/powerpc
wholesale, which included the debug bits, and then generalized it in
place. That was the safest way to transition without causing
breakage.

Moving it back into powerpc land is a step backwards. I've attached a
patch that makes it generic instead. It has been tested on ARM.

I've pushed it out to the following branch:

git://git.secretlab.ca/git/linux-2.6 irqdomain/merge

---

[PATCH] irqdomain: Remove powerpc dependency from debugfs file

The debugfs code is really generic for all platforms. This patch removes the
powerpc-specific directory reference and makes it available to all
architectures.

Signed-off-by: Grant Likely <grant.likely@xxxxxxxxxxxx>
---
arch/powerpc/Kconfig.debug | 10 ----------
kernel/irq/Kconfig | 10 ++++++++++
kernel/irq/irqdomain.c | 8 ++++----
3 files changed, 14 insertions(+), 14 deletions(-)

diff --git a/arch/powerpc/Kconfig.debug b/arch/powerpc/Kconfig.debug
index 72d55db..e5f2689 100644
--- a/arch/powerpc/Kconfig.debug
+++ b/arch/powerpc/Kconfig.debug
@@ -114,16 +114,6 @@ config DEBUGGER
depends on KGDB || XMON
default y

-config VIRQ_DEBUG
- bool "Expose hardware/virtual IRQ mapping via debugfs"
- depends on DEBUG_FS
- help
- This option will show the mapping relationship between hardware irq
- numbers and virtual irq numbers. The mapping is exposed via debugfs
- in the file powerpc/virq_mapping.
-
- If you don't know what this means you don't need it.
-
config BDI_SWITCH
bool "Include BDI-2000 user context switcher"
depends on DEBUG_KERNEL && PPC32
diff --git a/kernel/irq/Kconfig b/kernel/irq/Kconfig
index 5a38bf4..d8e323d 100644
--- a/kernel/irq/Kconfig
+++ b/kernel/irq/Kconfig
@@ -56,6 +56,16 @@ config GENERIC_IRQ_CHIP
config IRQ_DOMAIN
bool

+config IRQ_DOMAIN_DEBUG
+ bool "Expose hardware/virtual IRQ mapping via debugfs"
+ depends on IRQ_DOMAIN && DEBUG_FS
+ help
+ This option will show the mapping relationship between hardware irq
+ numbers and Linux irq numbers. The mapping is exposed via debugfs
+ in the file "virq_mapping".
+
+ If you don't know what this means you don't need it.
+
# Support forced irq threading
config IRQ_FORCED_THREADING
bool
diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index af48e59..3601f3f 100644
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -632,7 +632,7 @@ unsigned int irq_linear_revmap(struct irq_domain *domain,
return revmap[hwirq];
}

-#ifdef CONFIG_VIRQ_DEBUG
+#ifdef CONFIG_IRQ_DOMAIN_DEBUG
static int virq_debug_show(struct seq_file *m, void *private)
{
unsigned long flags;
@@ -668,7 +668,7 @@ static int virq_debug_show(struct seq_file *m, void *private)
data = irq_desc_get_chip_data(desc);
seq_printf(m, "0x%16p ", data);

- if (desc->irq_data.domain->of_node)
+ if (desc->irq_data.domain && desc->irq_data.domain->of_node)
p = desc->irq_data.domain->of_node->full_name;
else
p = none;
@@ -695,14 +695,14 @@ static const struct file_operations virq_debug_fops = {

static int __init irq_debugfs_init(void)
{
- if (debugfs_create_file("virq_mapping", S_IRUGO, powerpc_debugfs_root,
+ if (debugfs_create_file("irq_domain_mapping", S_IRUGO, NULL,
NULL, &virq_debug_fops) == NULL)
return -ENOMEM;

return 0;
}
__initcall(irq_debugfs_init);
-#endif /* CONFIG_VIRQ_DEBUG */
+#endif /* CONFIG_IRQ_DOMAIN_DEBUG */

int irq_domain_simple_map(struct irq_domain *d, unsigned int irq,
irq_hw_number_t hwirq)
--
1.7.9.1


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