* [PATCH] powerpc/powernv: Add a debugfs file to read the firmware console
@ 2013-10-08 7:46 Benjamin Herrenschmidt
2013-10-09 3:23 ` Michael Ellerman
0 siblings, 1 reply; 5+ messages in thread
From: Benjamin Herrenschmidt @ 2013-10-08 7:46 UTC (permalink / raw)
To: linuxppc-dev
With OPALv3, the firmware can provide the address of it's internal console
to Linux, which we can then display using debugfs. This is handy for
diagnostics and debugging.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---
diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index 2911abe..10d7894 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -17,6 +17,8 @@
#include <linux/interrupt.h>
#include <linux/notifier.h>
#include <linux/slab.h>
+#include <linux/debugfs.h>
+#include <linux/uaccess.h>
#include <asm/opal.h>
#include <asm/firmware.h>
@@ -27,6 +29,21 @@ struct opal {
u64 entry;
} opal;
+/* OPAL in-memory console */
+struct memcons {
+ uint64_t magic;
+#define MEMCONS_MAGIC 0x6630696567726173
+ uint64_t obuf_phys;
+ uint64_t ibuf_phys;
+ uint32_t obuf_size;
+ uint32_t ibuf_size;
+ uint32_t out_pos;
+#define MEMCONS_OUT_POS_WRAP 0x80000000u
+#define MEMCONS_OUT_POS_MASK 0x00ffffffu
+ uint32_t in_prod;
+ uint32_t in_cons;
+};
+
static struct device_node *opal_node;
static DEFINE_SPINLOCK(opal_write_lock);
extern u64 opal_mc_secondary_handler[];
@@ -369,6 +386,90 @@ static irqreturn_t opal_interrupt(int irq, void *data)
return IRQ_HANDLED;
}
+#ifdef CONFIG_DEBUG_FS
+static ssize_t opal_memcons_read(struct file *file, char __user *to,
+ size_t count, loff_t *ppos)
+{
+ struct memcons *mc = file->private_data;
+ size_t available, ret, chunk0, chunk1, lcount;
+ const char *start, *conbuf = __va(mc->obuf_phys);
+ loff_t opos, pos;
+
+ /*
+ * Find out how much is in the buffer. If it has wrapped
+ * the whole buffer, else just the beginning. It has wrapped
+ * if the next character is not \0
+ */
+ if (mc->out_pos & MEMCONS_OUT_POS_WRAP) {
+ available = mc->obuf_size;
+ chunk1 = mc->out_pos & MEMCONS_OUT_POS_MASK;
+ start = conbuf + chunk1;
+ chunk0 = mc->obuf_size - chunk1;
+ } else {
+ available = mc->out_pos;
+ start = conbuf;
+ chunk0 = available;
+ chunk1 = 0;
+ }
+
+ opos = pos = *ppos;
+
+ /* Sanity check arguments */
+ if (pos < 0)
+ return -EINVAL;
+ if (pos >= available || !count)
+ return 0;
+ if (count > available - pos)
+ count = available - pos;
+
+ /* Handle first chunk */
+ if (pos < chunk0) {
+ lcount = min(count, chunk0 - (size_t)pos);
+ ret = copy_to_user(to, start + pos, lcount);
+ if (ret == lcount)
+ return -EFAULT;
+ lcount -= ret;
+ count -= lcount;
+ *ppos += lcount;
+ to += lcount;
+ pos = 0;
+ } else {
+ *ppos += chunk0;
+ pos -= chunk0;
+ ret = 0;
+ }
+
+ /* Handle second chunk */
+ if (count && chunk1 && ret == 0) {
+ lcount = min(count, chunk1 - (size_t)pos);
+ ret = copy_to_user(to, conbuf + pos, lcount);
+ if (ret == lcount)
+ return -EFAULT;
+ lcount -= ret;
+ *ppos += lcount;
+ }
+ return *ppos - opos;
+
+}
+
+static const struct file_operations opal_fops_memcons = {
+ .read = opal_memcons_read,
+ .open = simple_open,
+ .llseek = default_llseek,
+};
+
+static void opal_init_debugfs(void)
+{
+ u64 mcaddr;
+
+ if (of_property_read_u64(opal_node, "ibm,opal-memcons", &mcaddr) == 0)
+ debugfs_create_file("opal-log", 0400, powerpc_debugfs_root,
+ __va(mcaddr), &opal_fops_memcons);
+}
+#else
+static void opal_init_debugfs(void) { }
+#endif /* CONFIG_DEBUG_FS */
+
static int __init opal_init(void)
{
struct device_node *np, *consoles;
@@ -414,6 +515,9 @@ static int __init opal_init(void)
" (0x%x)\n", rc, irq, hwirq);
opal_irqs[i] = irq;
}
+
+ opal_init_debugfs();
+
return 0;
}
subsys_initcall(opal_init);
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH] powerpc/powernv: Add a debugfs file to read the firmware console
2013-10-08 7:46 [PATCH] powerpc/powernv: Add a debugfs file to read the firmware console Benjamin Herrenschmidt
@ 2013-10-09 3:23 ` Michael Ellerman
2013-10-09 4:23 ` Benjamin Herrenschmidt
0 siblings, 1 reply; 5+ messages in thread
From: Michael Ellerman @ 2013-10-09 3:23 UTC (permalink / raw)
To: Benjamin Herrenschmidt; +Cc: linuxppc-dev
On Tue, Oct 08, 2013 at 06:46:40PM +1100, Benjamin Herrenschmidt wrote:
> With OPALv3, the firmware can provide the address of it's internal console
> to Linux, which we can then display using debugfs. This is handy for
> diagnostics and debugging.
>
> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> ---
>
> diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
> index 2911abe..10d7894 100644
> --- a/arch/powerpc/platforms/powernv/opal.c
> +++ b/arch/powerpc/platforms/powernv/opal.c
> @@ -17,6 +17,8 @@
> #include <linux/interrupt.h>
> #include <linux/notifier.h>
> #include <linux/slab.h>
> +#include <linux/debugfs.h>
> +#include <linux/uaccess.h>
> #include <asm/opal.h>
> #include <asm/firmware.h>
>
> @@ -27,6 +29,21 @@ struct opal {
> u64 entry;
> } opal;
>
> +/* OPAL in-memory console */
It might be nice to point out that the format of the struct is defined
by OPAL and must be in sync with what OPAL is using.
> +struct memcons {
> + uint64_t magic;
u64 ?
> +#define MEMCONS_MAGIC 0x6630696567726173
> + uint64_t obuf_phys;
> + uint64_t ibuf_phys;
> + uint32_t obuf_size;
> + uint32_t ibuf_size;
> + uint32_t out_pos;
> +#define MEMCONS_OUT_POS_WRAP 0x80000000u
> +#define MEMCONS_OUT_POS_MASK 0x00ffffffu
Where does this come from?
> + uint32_t in_prod;
> + uint32_t in_cons;
> +};
Should it be packed?
> @@ -369,6 +386,90 @@ static irqreturn_t opal_interrupt(int irq, void *data)
> return IRQ_HANDLED;
> }
>
> +#ifdef CONFIG_DEBUG_FS
> +static ssize_t opal_memcons_read(struct file *file, char __user *to,
> + size_t count, loff_t *ppos)
> +{
> + struct memcons *mc = file->private_data;
> + size_t available, ret, chunk0, chunk1, lcount;
> + const char *start, *conbuf = __va(mc->obuf_phys);
> + loff_t opos, pos;
> +
> + /*
> + * Find out how much is in the buffer. If it has wrapped
> + * the whole buffer, else just the beginning. It has wrapped
> + * if the next character is not \0
> + */
> + if (mc->out_pos & MEMCONS_OUT_POS_WRAP) {
> + available = mc->obuf_size;
> + chunk1 = mc->out_pos & MEMCONS_OUT_POS_MASK;
> + start = conbuf + chunk1;
> + chunk0 = mc->obuf_size - chunk1;
> + } else {
> + available = mc->out_pos;
> + start = conbuf;
> + chunk0 = available;
> + chunk1 = 0;
> + }
Surely simple_read_from_buffer() could make some of this simpler?
cheers
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] powerpc/powernv: Add a debugfs file to read the firmware console
2013-10-09 3:23 ` Michael Ellerman
@ 2013-10-09 4:23 ` Benjamin Herrenschmidt
2013-10-09 6:06 ` Michael Ellerman
0 siblings, 1 reply; 5+ messages in thread
From: Benjamin Herrenschmidt @ 2013-10-09 4:23 UTC (permalink / raw)
To: Michael Ellerman; +Cc: linuxppc-dev
On Wed, 2013-10-09 at 14:23 +1100, Michael Ellerman wrote:
> On Tue, Oct 08, 2013 at 06:46:40PM +1100, Benjamin Herrenschmidt wrote:
> > With OPALv3, the firmware can provide the address of it's internal console
> > to Linux, which we can then display using debugfs. This is handy for
> > diagnostics and debugging.
> >
> > Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> > ---
> >
> > diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
> > index 2911abe..10d7894 100644
> > --- a/arch/powerpc/platforms/powernv/opal.c
> > +++ b/arch/powerpc/platforms/powernv/opal.c
> > @@ -17,6 +17,8 @@
> > #include <linux/interrupt.h>
> > #include <linux/notifier.h>
> > #include <linux/slab.h>
> > +#include <linux/debugfs.h>
> > +#include <linux/uaccess.h>
> > #include <asm/opal.h>
> > #include <asm/firmware.h>
> >
> > @@ -27,6 +29,21 @@ struct opal {
> > u64 entry;
> > } opal;
> >
> > +/* OPAL in-memory console */
>
> It might be nice to point out that the format of the struct is defined
> by OPAL and must be in sync with what OPAL is using.
Yes, we could move the structure definition to opal.h...
> > +struct memcons {
> > + uint64_t magic;
>
> u64 ?
Who cares ? Especially if it goes into opal.h it should stick to the
types used in that file.
> > +#define MEMCONS_MAGIC 0x6630696567726173
> > + uint64_t obuf_phys;
> > + uint64_t ibuf_phys;
> > + uint32_t obuf_size;
> > + uint32_t ibuf_size;
> > + uint32_t out_pos;
> > +#define MEMCONS_OUT_POS_WRAP 0x80000000u
> > +#define MEMCONS_OUT_POS_MASK 0x00ffffffu
>
> Where does this come from?
My a** :-) I made it up as I wrote the OPAL side one, why ?
> > + uint32_t in_prod;
> > + uint32_t in_cons;
> > +};
>
> Should it be packed?
Nope, no need. It's all nice and naturally aligned.
> > @@ -369,6 +386,90 @@ static irqreturn_t opal_interrupt(int irq, void *data)
> > return IRQ_HANDLED;
> > }
> >
> > +#ifdef CONFIG_DEBUG_FS
> > +static ssize_t opal_memcons_read(struct file *file, char __user *to,
> > + size_t count, loff_t *ppos)
> > +{
> > + struct memcons *mc = file->private_data;
> > + size_t available, ret, chunk0, chunk1, lcount;
> > + const char *start, *conbuf = __va(mc->obuf_phys);
> > + loff_t opos, pos;
> > +
> > + /*
> > + * Find out how much is in the buffer. If it has wrapped
> > + * the whole buffer, else just the beginning. It has wrapped
> > + * if the next character is not \0
> > + */
> > + if (mc->out_pos & MEMCONS_OUT_POS_WRAP) {
> > + available = mc->obuf_size;
> > + chunk1 = mc->out_pos & MEMCONS_OUT_POS_MASK;
> > + start = conbuf + chunk1;
> > + chunk0 = mc->obuf_size - chunk1;
> > + } else {
> > + available = mc->out_pos;
> > + start = conbuf;
> > + chunk0 = available;
> > + chunk1 = 0;
> > + }
>
> Surely simple_read_from_buffer() could make some of this simpler?
If you can find a way to make it deal with a ring buffer...
Cheers,
Ben.
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] powerpc/powernv: Add a debugfs file to read the firmware console
2013-10-09 4:23 ` Benjamin Herrenschmidt
@ 2013-10-09 6:06 ` Michael Ellerman
2013-10-09 6:51 ` Benjamin Herrenschmidt
0 siblings, 1 reply; 5+ messages in thread
From: Michael Ellerman @ 2013-10-09 6:06 UTC (permalink / raw)
To: Benjamin Herrenschmidt; +Cc: linuxppc-dev
On Wed, Oct 09, 2013 at 03:23:21PM +1100, Benjamin Herrenschmidt wrote:
> On Wed, 2013-10-09 at 14:23 +1100, Michael Ellerman wrote:
> > On Tue, Oct 08, 2013 at 06:46:40PM +1100, Benjamin Herrenschmidt wrote:
> > > With OPALv3, the firmware can provide the address of it's internal console
> > > to Linux, which we can then display using debugfs. This is handy for
> > > diagnostics and debugging.
> > >
> > > Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> > > ---
> > >
> > > diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
> > > index 2911abe..10d7894 100644
> > > --- a/arch/powerpc/platforms/powernv/opal.c
> > > +++ b/arch/powerpc/platforms/powernv/opal.c
> > > @@ -17,6 +17,8 @@
> > > #include <linux/interrupt.h>
> > > #include <linux/notifier.h>
> > > #include <linux/slab.h>
> > > +#include <linux/debugfs.h>
> > > +#include <linux/uaccess.h>
> > > #include <asm/opal.h>
> > > #include <asm/firmware.h>
> > >
> > > @@ -27,6 +29,21 @@ struct opal {
> > > u64 entry;
> > > } opal;
> > >
> > > +/* OPAL in-memory console */
> >
> > It might be nice to point out that the format of the struct is defined
> > by OPAL and must be in sync with what OPAL is using.
>
> Yes, we could move the structure definition to opal.h...
>
> > > +struct memcons {
> > > + uint64_t magic;
> >
> > u64 ?
>
> Who cares ?
That's what we use in the kernel. But no I don't care.
> > > +#define MEMCONS_MAGIC 0x6630696567726173
> > > + uint64_t obuf_phys;
> > > + uint64_t ibuf_phys;
> > > + uint32_t obuf_size;
> > > + uint32_t ibuf_size;
> > > + uint32_t out_pos;
> > > +#define MEMCONS_OUT_POS_WRAP 0x80000000u
> > > +#define MEMCONS_OUT_POS_MASK 0x00ffffffu
> >
> > Where does this come from?
>
> My a** :-) I made it up as I wrote the OPAL side one, why ?
...
> > > + uint32_t in_prod;
> > > + uint32_t in_cons;
> > > +};
> >
> > Should it be packed?
>
> Nope, no need. It's all nice and naturally aligned.
Sure, that's obvious.
> > > @@ -369,6 +386,90 @@ static irqreturn_t opal_interrupt(int irq, void *data)
> > > return IRQ_HANDLED;
> > > }
> > >
> > > +#ifdef CONFIG_DEBUG_FS
> > > +static ssize_t opal_memcons_read(struct file *file, char __user *to,
> > > + size_t count, loff_t *ppos)
> > > +{
> > > + struct memcons *mc = file->private_data;
> > > + size_t available, ret, chunk0, chunk1, lcount;
> > > + const char *start, *conbuf = __va(mc->obuf_phys);
> > > + loff_t opos, pos;
> > > +
> > > + /*
> > > + * Find out how much is in the buffer. If it has wrapped
> > > + * the whole buffer, else just the beginning. It has wrapped
> > > + * if the next character is not \0
> > > + */
> > > + if (mc->out_pos & MEMCONS_OUT_POS_WRAP) {
> > > + available = mc->obuf_size;
> > > + chunk1 = mc->out_pos & MEMCONS_OUT_POS_MASK;
> > > + start = conbuf + chunk1;
> > > + chunk0 = mc->obuf_size - chunk1;
> > > + } else {
> > > + available = mc->out_pos;
> > > + start = conbuf;
> > > + chunk0 = available;
> > > + chunk1 = 0;
> > > + }
> >
> > Surely simple_read_from_buffer() could make some of this simpler?
>
> If you can find a way to make it deal with a ring buffer...
Call it twice.
And you wonder why no one reviews your patches?
cheers
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH] powerpc/powernv: Add a debugfs file to read the firmware console
2013-10-09 6:06 ` Michael Ellerman
@ 2013-10-09 6:51 ` Benjamin Herrenschmidt
0 siblings, 0 replies; 5+ messages in thread
From: Benjamin Herrenschmidt @ 2013-10-09 6:51 UTC (permalink / raw)
To: Michael Ellerman; +Cc: linuxppc-dev
On Wed, 2013-10-09 at 17:06 +1100, Michael Ellerman wrote:
> Call it twice.
>
> And you wonder why no one reviews your patches?
Not that easy :-) I had a look at using it and unless I did something
stupid, it wasn't actually that trivial to figure out what arg to pass
it for calling it twice, ie, it didn't simplify the code
significantly ... I had another problem too but I don't remember what
it was. But it could be that I had a very dumb moment...
Cheers,
Ben.
^ permalink raw reply [flat|nested] 5+ messages in thread
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2013-10-08 7:46 [PATCH] powerpc/powernv: Add a debugfs file to read the firmware console Benjamin Herrenschmidt
2013-10-09 3:23 ` Michael Ellerman
2013-10-09 4:23 ` Benjamin Herrenschmidt
2013-10-09 6:06 ` Michael Ellerman
2013-10-09 6:51 ` Benjamin Herrenschmidt
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