Hi Paul,
On Fri, 2021-06-18 at 15:31 +1200, Paul Davey wrote:
> On big endian architectures the mhi debugfs files which report pm
> state
> give "Invalid State" for all states.
>
> Fix to_mhi_pm_state_str by using a local unsigned long as an
> intemediate
> to pass the state to find_last_bit to avoid endianness issues with
> cast
> from enum mhi_pm_state * to unsigned long *.
>
> Signed-off-by: Paul Davey <paul.davey@xxxxxxxxxxxxxxxxxxx>
> ---
> drivers/bus/mhi/core/init.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/bus/mhi/core/init.c
> b/drivers/bus/mhi/core/init.c
> index c81b377fca8f..87cc0c449078 100644
> --- a/drivers/bus/mhi/core/init.c
> +++ b/drivers/bus/mhi/core/init.c
> @@ -79,7 +79,8 @@ static const char * const mhi_pm_state_str[] = {
>
> const char *to_mhi_pm_state_str(enum mhi_pm_state state)
> {
> - int index = find_last_bit((unsigned long *)&state, 32);
> + unsigned long tmp = state;
> + int index = find_last_bit((unsigned long *)&tmp, 32);
>
> if (index >= ARRAY_SIZE(mhi_pm_state_str))
> return "Invalid State";
Considering KASAN bugs reported in the past related to find_next_bit
https://www.spinics.net/lists/alsa-devel/msg110946.html
Since you are addressing the BE arch issue, would you please
use this solution instead :-
diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
index 8f4cd4d..744b617 100644
--- a/drivers/bus/mhi/core/init.c
+++ b/drivers/bus/mhi/core/init.c
@@ -77,9 +77,12 @@ static const char * const mhi_pm_state_str[] = {
const char *to_mhi_pm_state_str(enum mhi_pm_state state)
{
+ int index;
- if (index >= ARRAY_SIZE(mhi_pm_state_str))
+ if (state)
+ index = __fls(state);
+
+ if (!state || index >= ARRAY_SIZE(mhi_pm_state_str))
return "Invalid State";
return mhi_pm_state_str[index];
Thanks,
Hemant
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