[PATCH v3 5/6] ramoops: Add max_reason optional field to ramoops DT node

Kees Cook
2020-05-06T21:15:52Z

From: Pavel Tatashin <pasha.tatashin@soleen.com>

Currently, it is possible to dump kmsges for panic, or oops.
With max_reason it is possible to dump messages for other
kmesg_dump events, for example reboot, halt, shutdown, kexec.

Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Link: https://lore.kernel.org/r/20200505154510.93506-6-pasha.tatashin@soleen.com
Signed-off-by: Kees Cook <keescook@chromium.org>
---
.../devicetree/bindings/reserved-memory/ramoops.txt | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/Documentation/devicetree/bindings/reserved-memory/ramoops.txt b/Documentation/devicetree/bindings/reserved-memory/ramoops.txt
index 0eba562fe5c6..b7886fea368c 100644
--- a/Documentation/devicetree/bindings/reserved-memory/ramoops.txt
+++ b/Documentation/devicetree/bindings/reserved-memory/ramoops.txt
@@ -30,7 +30,7 @@ Optional properties:
- ecc-size: enables ECC support and specifies ECC buffer size in bytes
(defaults to 0: no ECC)

-- record-size: maximum size in bytes of each dump done on oops/panic
+- record-size: maximum size in bytes of each kmsg dump.
(defaults to 0: disabled)

- console-size: size in bytes of log buffer reserved for kernel messages
@@ -45,7 +45,16 @@ Optional properties:
- unbuffered: if present, use unbuffered mappings to map the reserved region
(defaults to buffered mappings)

-- no-dump-oops: if present, only dump panics (defaults to panics and oops)
+- max-reason: if present, sets maximum type of kmsg dump reasons to store
+ (defaults to 2: log Oopses and Panics). This can be set to INT_MAX to
+ store all kmsg dumps. See include/linux/kmsg_dump.h KMSG_DUMP_* for other
+ kmsg dump reason values. 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 will be KMSG_DUMP_OOPS, otherwise KMSG_DUMP_MAX.
+
+- no-dump-oops: deprecated, use max_reason instead. If present, and
+ max_reason is not specified, it is equivalent to max_reason = 1
+ (KMSG_DUMP_PANIC).

- flags: if present, pass ramoops behavioral flags (defaults to 0,
see include/linux/pstore_ram.h RAMOOPS_FLAG_* for flag values).
--
2.20.1