From: Douglas Anderson <dianders@xxxxxxxxxxxx> Date: Fri, May 3, 2019 at 10:48 AM To: Kees Cook, Anton Vorontsov Cc: <linux-rockchip@xxxxxxxxxxxxxxxxxxx>, <jwerner@xxxxxxxxxxxx>, <groeck@xxxxxxxxxxxx>, <mka@xxxxxxxxxxxx>, <briannorris@xxxxxxxxxxxx>, Douglas Anderson, Colin Cross, Tony Luck, <linux-kernel@xxxxxxxxxxxxxxx> > When you try to run an upstream kernel on an old ARM-based Chromebook > you'll find that console-ramoops doesn't work. > > Old ARM-based Chromebooks, before <https://crrev.com/c/439792> > ("ramoops: support upstream {console,pmsg,ftrace}-size properties") > used to create a "ramoops" node at the top level that looked like: > > / { > ramoops { > compatible = "ramoops"; > reg = <...>; > record-size = <...>; > dump-oops; > }; > }; > > ...and these Chromebooks assumed that the downstream kernel would make > console_size / pmsg_size match the record size. The above ramoops > node was added by the firmware so it's not easy to make any changes. > > Let's match the expected behavior, but only for those using the old > backward-compatible way of working where ramoops is right under the > root node. > > NOTE: if there are some out-of-tree devices that had ramoops at the > top level, left everything but the record size as 0, and somehow > doesn't want this behavior, we can try to add more conditions here. > > Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx> I like this; thanks! Rob is this okay by you? I just want to double-check since it's part of the DT parsing logic. I'll pick it up and add a Cc: stable. -Kees > --- > > fs/pstore/ram.c | 18 ++++++++++++++++++ > 1 file changed, 18 insertions(+) > > diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c > index c5c685589e36..8df3bfa2837f 100644 > --- a/fs/pstore/ram.c > +++ b/fs/pstore/ram.c > @@ -669,6 +669,7 @@ static int ramoops_parse_dt(struct platform_device *pdev, > struct ramoops_platform_data *pdata) > { > struct device_node *of_node = pdev->dev.of_node; > + struct device_node *parent_node; > struct resource *res; > u32 value; > int ret; > @@ -703,6 +704,23 @@ static int ramoops_parse_dt(struct platform_device *pdev, > > #undef parse_size > > + /* > + * Some old Chromebooks relied on the kernel setting the console_size > + * and pmsg_size to the record size since that's what the downstream > + * kernel did. These same Chromebooks had "ramoops" straight under > + * the root node which isn't according to the upstream bindings. Let's > + * make those old Chromebooks work by detecting this and mimicing the > + * expected behavior. > + */ > + parent_node = of_get_parent(of_node); > + if (of_node_is_root(parent_node) && > + !pdata->console_size && !pdata->ftrace_size && > + !pdata->pmsg_size && !pdata->ecc_info.ecc_size) { > + pdata->console_size = pdata->record_size; > + pdata->pmsg_size = pdata->record_size; > + } > + of_node_put(parent_node); > + > return 0; > } > > -- > 2.21.0.1020.gf2820cf01a-goog > -- Kees Cook _______________________________________________ Linux-rockchip mailing list Linux-rockchip@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/linux-rockchip
