diff mbox

[2/6] pstore/ram: Add console messages handling

Message ID 20120516125634.GB20475@lizard
State New
Headers show

Commit Message

Anton Vorontsov May 16, 2012, 12:56 p.m. UTC
This is all straightforward: we just use the last region for
console logging. If there's just one region, we fall-back to
the old behaviour: just a oops/dumps logging.

Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
---
 fs/pstore/ram.c |   39 ++++++++++++++++++++++++++++++---------
 1 file changed, 30 insertions(+), 9 deletions(-)

Comments

Shuah Khan May 16, 2012, 3:30 p.m. UTC | #1
On Wed, 2012-05-16 at 05:56 -0700, Anton Vorontsov wrote:
> This is all straightforward: we just use the last region for
> console logging. If there's just one region, we fall-back to
> the old behaviour: just a oops/dumps logging.

What about the saving /proc/last_kmsg? Are you not bringing that feature
from ramconsole? Sorry if I missed it in reading the patches.

-- Shuah
Kees Cook May 16, 2012, 4:45 p.m. UTC | #2
On Wed, May 16, 2012 at 5:56 AM, Anton Vorontsov
<anton.vorontsov@linaro.org> wrote:
> This is all straightforward: we just use the last region for
> console logging. If there's just one region, we fall-back to
> the old behaviour: just a oops/dumps logging.
>
> Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
> ---
>  fs/pstore/ram.c |   39 ++++++++++++++++++++++++++++++---------
>  1 file changed, 30 insertions(+), 9 deletions(-)
>
> diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
> index 9123cce..54213eb 100644
> --- a/fs/pstore/ram.c
> +++ b/fs/pstore/ram.c
> [...]
> @@ -142,7 +148,12 @@ static int ramoops_pstore_write(enum pstore_type_id type,
>        struct persistent_ram_zone *prz = cxt->przs[cxt->count];
>        size_t hlen;
>
> -       /* Currently ramoops is designed to only store dmesg dumps. */
> +       if (type == PSTORE_TYPE_CONSOLE) {
> +               if (!cxt->cprz)
> +                       return -ENOMEM;
> +               persistent_ram_write(cxt->cprz, cxt->pstore.buf, size);
> +       }
> +
>        if (type != PSTORE_TYPE_DMESG)
>                return -EINVAL;

Doesn't this mean that type == PSTORE_TYPE_CONSOLE will write to the
ram, but then fail with -EINVAL?

-Kees
Anton Vorontsov May 16, 2012, 10:20 p.m. UTC | #3
On Wed, May 16, 2012 at 09:30:52AM -0600, Shuah Khan wrote:
> On Wed, 2012-05-16 at 05:56 -0700, Anton Vorontsov wrote:
> > This is all straightforward: we just use the last region for
> > console logging. If there's just one region, we fall-back to
> > the old behaviour: just a oops/dumps logging.
> 
> What about the saving /proc/last_kmsg? Are you not bringing that feature
> from ramconsole? Sorry if I missed it in reading the patches.

Nope, sorry. The /proc/last_kms ABI is just a duplication of
pstore's console logging interface, and since last_kmsg thing is
in drivers/staging/, there's no point in keeping it, unless there's
a really good reason.

Thanks!
Anton Vorontsov May 16, 2012, 10:28 p.m. UTC | #4
On Wed, May 16, 2012 at 09:45:35AM -0700, Kees Cook wrote:
> On Wed, May 16, 2012 at 5:56 AM, Anton Vorontsov
> <anton.vorontsov@linaro.org> wrote:
> > This is all straightforward: we just use the last region for
> > console logging. If there's just one region, we fall-back to
> > the old behaviour: just a oops/dumps logging.
> >
> > Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
> > ---
> >  fs/pstore/ram.c |   39 ++++++++++++++++++++++++++++++---------
> >  1 file changed, 30 insertions(+), 9 deletions(-)
> >
> > diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
> > index 9123cce..54213eb 100644
> > --- a/fs/pstore/ram.c
> > +++ b/fs/pstore/ram.c
> > [...]
> > @@ -142,7 +148,12 @@ static int ramoops_pstore_write(enum pstore_type_id type,
> >        struct persistent_ram_zone *prz = cxt->przs[cxt->count];
> >        size_t hlen;
> >
> > -       /* Currently ramoops is designed to only store dmesg dumps. */
> > +       if (type == PSTORE_TYPE_CONSOLE) {
> > +               if (!cxt->cprz)
> > +                       return -ENOMEM;
> > +               persistent_ram_write(cxt->cprz, cxt->pstore.buf, size);
> > +       }
> > +
> >        if (type != PSTORE_TYPE_DMESG)
> >                return -EINVAL;
> 
> Doesn't this mean that type == PSTORE_TYPE_CONSOLE will write to the
> ram, but then fail with -EINVAL?

Right you are, there should be 'return 0' for TYPE_CONSOLE. It is
harmless tho (and unnoticeable, since we can't check return value of
the ->write() calback and print error, since this would recurse),
but I'll surely amend that.

Thanks!
diff mbox

Patch

diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 9123cce..54213eb 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -63,6 +63,7 @@  MODULE_PARM_DESC(ramoops_ecc,
 
 struct ramoops_context {
 	struct persistent_ram_zone **przs;
+	struct persistent_ram_zone *cprz;
 	phys_addr_t phys_addr;
 	unsigned long size;
 	size_t record_size;
@@ -70,6 +71,7 @@  struct ramoops_context {
 	bool ecc;
 	unsigned int count;
 	unsigned int max_count;
+	unsigned int max_dump_count;
 	unsigned int read_count;
 	struct pstore_info pstore;
 };
@@ -92,16 +94,20 @@  static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type,
 {
 	ssize_t size;
 	struct ramoops_context *cxt = psi->data;
-	struct persistent_ram_zone *prz;
-
-	if (cxt->read_count >= cxt->max_count)
-		return -EINVAL;
+	struct persistent_ram_zone *prz = cxt->przs[cxt->read_count];
 
 	*id = cxt->read_count++;
-	prz = cxt->przs[*id];
 
-	/* Only supports dmesg output so far. */
-	*type = PSTORE_TYPE_DMESG;
+	if (*id < cxt->max_dump_count && persistent_ram_old_size(prz)) {
+		*type = PSTORE_TYPE_DMESG;
+	} else if (*id < cxt->max_count) {
+		*type = PSTORE_TYPE_CONSOLE;
+		prz = cxt->cprz;
+		cxt->read_count = cxt->max_count;
+	} else {
+		return 0;
+	}
+
 	/* TODO(kees): Bogus time for the moment. */
 	time->tv_sec = 0;
 	time->tv_nsec = 0;
@@ -142,7 +148,12 @@  static int ramoops_pstore_write(enum pstore_type_id type,
 	struct persistent_ram_zone *prz = cxt->przs[cxt->count];
 	size_t hlen;
 
-	/* Currently ramoops is designed to only store dmesg dumps. */
+	if (type == PSTORE_TYPE_CONSOLE) {
+		if (!cxt->cprz)
+			return -ENOMEM;
+		persistent_ram_write(cxt->cprz, cxt->pstore.buf, size);
+	}
+
 	if (type != PSTORE_TYPE_DMESG)
 		return -EINVAL;
 
@@ -170,7 +181,7 @@  static int ramoops_pstore_write(enum pstore_type_id type,
 		size = prz->buffer_size - hlen;
 	persistent_ram_write(prz, cxt->pstore.buf, size);
 
-	cxt->count = (cxt->count + 1) % cxt->max_count;
+	cxt->count = (cxt->count + 1) % cxt->max_dump_count;
 
 	return 0;
 }
@@ -264,6 +275,16 @@  static int __init ramoops_probe(struct platform_device *pdev)
 		}
 	}
 
+	/*
+	 * The last zone is for TYPE_CONSOLE, unless we have only
+	 * one, in which case we use it for oops/panic logging.
+	 */
+	cxt->max_dump_count = cxt->max_count;
+	if (cxt->max_count > 1) {
+		cxt->max_dump_count--;
+		cxt->cprz = cxt->przs[cxt->max_count - 1];
+	}
+
 	cxt->pstore.data = cxt;
 	cxt->pstore.bufsize = cxt->przs[0]->buffer_size;
 	cxt->pstore.buf = kmalloc(cxt->pstore.bufsize, GFP_KERNEL);