[PATCH V2] ARM: dts: bcm283x: Reserve first page for firmware
eric at anholt.net
Tue May 16 15:19:51 PDT 2017
Florian Fainelli <f.fainelli at gmail.com> writes:
> On 05/09/2017 02:04 AM, Phil Elwell wrote:
>> The Raspberry Pi startup stub files for multi-core BCM27XX processors
>> make the secondary CPUs spin until the corresponding mailbox is
>> written. These stubs are loaded at physical address 0x00000xxx (as seen
>> by the ARMs), but this page will be reused by the kernel unless it is
>> explicitly reserved, causing the waiting cores to execute random code.
>> Use the /memreserve/ Device Tree directive to mark the first page as
>> off-limits to the kernel.
> This reserves a 4KB page here, is this good enough, or should we just go
> directly to the maximum page granule size possible on an ARM64/Linux
> system to be on the safe side?
>> See: https://github.com/raspberrypi/linux/issues/1989
>> Signed-off-by: Phil Elwell <phil at raspberrypi.org>
>> Changes in V2:
>> - Rebase against linux-next
>> - Drop downstream-only patch
>> arch/arm/boot/dts/bcm283x.dtsi | 2 ++
>> 1 file changed, 2 insertions(+)
>> diff --git a/arch/arm/boot/dts/bcm283x.dtsi b/arch/arm/boot/dts/bcm283x.dtsi
>> index a3106aa..6d12c3e8 100644
>> --- a/arch/arm/boot/dts/bcm283x.dtsi
>> +++ b/arch/arm/boot/dts/bcm283x.dtsi
>> @@ -3,6 +3,8 @@
>> #include <dt-bindings/clock/bcm2835-aux.h>
>> #include <dt-bindings/gpio/gpio.h>
>> +/memreserve/ 0x00000000 0x00001000;
> Can you put a comment above this /memreserve entry here to remind about
> what this is useful for?
Phil, I chatted with Florian and added in:
+/* firmware-provided startup stubs live here, where the secondary CPUs are
+ * spinning.
and tagged and sent a PR for 4.12. Thanks!
-------------- next part --------------
A non-text attachment was scrubbed...
Size: 832 bytes
Desc: not available
More information about the linux-rpi-kernel