Now that pstore_register() can correctly pass max_reason to the kmesg
dump facility, introduce a new "max_reason" module parameter and
"max-reason" Device Tree field.
The "dump_oops" module parameter and "dump-oops" Device
Tree field are now considered deprecated, but are now automatically
converted to their corresponding max_reason values when present, though
the new max_reason setting has precedence.
For struct ramoops_platform_data, the "dump_oops" member is entirely
replaced by a new "max_reason" member, with the only existing user
updated in place.
Additionally remove the "reason" filter logic from ramoops_pstore_write(),
as that is not specifically needed anymore, though technically
this is a change in behavior for any ramoops users also setting the
printk.always_kmsg_dump boot param, which will cause ramoops to behave as
if max_reason was set to KMSG_DUMP_MAX.
Co-developed-by: Pavel Tatashin
Signed-off-by: Pavel Tatashin
Link: https://lore.kernel.org/lkml/20200506211523.15077-5-keesc...@chromium.org/
Signed-off-by: Kees Cook
---
Documentation/admin-guide/ramoops.rst | 14 --
drivers/platform/chrome/chromeos_pstore.c | 2 +-
fs/pstore/ram.c | 58 +++
include/linux/pstore_ram.h| 2 +-
4 files changed, 51 insertions(+), 25 deletions(-)
diff --git a/Documentation/admin-guide/ramoops.rst
b/Documentation/admin-guide/ramoops.rst
index 6dbcc5481000..a60a96218ba9 100644
--- a/Documentation/admin-guide/ramoops.rst
+++ b/Documentation/admin-guide/ramoops.rst
@@ -32,11 +32,17 @@ memory to be mapped strongly ordered, and atomic operations
on strongly ordered
memory are implementation defined, and won't work on many ARMs such as omaps.
The memory area is divided into ``record_size`` chunks (also rounded down to
-power of two) and each oops/panic writes a ``record_size`` chunk of
+power of two) and each kmesg dump writes a ``record_size`` chunk of
information.
-Dumping both oopses and panics can be done by setting 1 in the ``dump_oops``
-variable while setting 0 in that variable dumps only the panics.
+Limiting which kinds of kmsg dumps are stored can be controlled via
+the ``max_reason`` value, as defined in include/linux/kmsg_dump.h's
+``enum kmsg_dump_reason``. For example, to store both Oopses and Panics,
+``max_reason`` should be set to 2 (KMSG_DUMP_OOPS), to store only Panics
+``max_reason`` should be set to 1 (KMSG_DUMP_PANIC). Setting this to 0
+(KMSG_DUMP_UNDEF), means the reason filtering will be controlled by the
+``printk.always_kmsg_dump`` boot param: if unset, it'll be KMSG_DUMP_OOPS,
+otherwise KMSG_DUMP_MAX.
The module uses a counter to record multiple dumps but the counter gets reset
on restart (i.e. new dumps after the restart will overwrite old ones).
@@ -90,7 +96,7 @@ Setting the ramoops parameters can be done in several
different manners:
.mem_address= <...>,
.mem_type = <...>,
.record_size= <...>,
-.dump_oops = <...>,
+.max_reason = <...>,
.ecc= <...>,
};
diff --git a/drivers/platform/chrome/chromeos_pstore.c
b/drivers/platform/chrome/chromeos_pstore.c
index d13770785fb5..fa51153688b4 100644
--- a/drivers/platform/chrome/chromeos_pstore.c
+++ b/drivers/platform/chrome/chromeos_pstore.c
@@ -57,7 +57,7 @@ static struct ramoops_platform_data chromeos_ramoops_data = {
.record_size= 0x4,
.console_size = 0x2,
.ftrace_size= 0x2,
- .dump_oops = 1,
+ .max_reason = KMSG_DUMP_OOPS,
};
static struct platform_device chromeos_ramoops = {
diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 31f277633beb..f6eace1dbf7e 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -58,10 +58,10 @@ module_param(mem_type, uint, 0400);
MODULE_PARM_DESC(mem_type,
"set to 1 to try to use unbuffered memory (default 0)");
-static int dump_oops = 1;
-module_param(dump_oops, int, 0400);
-MODULE_PARM_DESC(dump_oops,
- "set to 1 to dump oopses, 0 to only dump panics (default 1)");
+static int ramoops_max_reason = -1;
+module_param_named(max_reason, ramoops_max_reason, int, 0400);
+MODULE_PARM_DESC(max_reason,
+"maximum reason for kmsg dump (default 2: Oops and Panic) ");
static int ramoops_ecc;
module_param_named(ecc, ramoops_ecc, int, 0400);
@@ -70,6 +70,11 @@ MODULE_PARM_DESC(ramoops_ecc,
"ECC buffer size in bytes (1 is a special value, means 16 "
"bytes ECC)");
+static int ramoops_dump_oops = -1;
+module_param_named(dump_oops, ramoops_dump_oops, int, 0400);
+MODULE_PARM_DESC(dump_oops,
+"(deprecated: use max_reason instead) set to 1 to dump oopses
& panics, 0 to only dump panics");
+
struct ramoops_context {
struct persistent_ram_zone **dprzs; /* Oops dump zones */
struct persistent_ram_zone *cprz;
