Hi,
From: Rafael J. Wysocki [mailto:rjw@rjwysocki.net] Sent: Wednesday, September 16, 2015 9:57 AM
On Tuesday, September 15, 2015 02:04:58 PM Viresh Kumar wrote:
global_lock is defined as an unsigned long and accessing only its lower 32 bits from sysfs is incorrect, as we need to consider other 32 bits for big endian 64 bit systems.
Fix that by making global_lock an u32 instead.
Cc: stable@vger.kernel.org # v4.1+ Signed-off-by: Viresh Kumar viresh.kumar@linaro.org
Its marked just for # v4.1+, because arm64 has the first 64 big-endian platform with ACPI. And ACPI support for that is mainlined recently only (Arnd Bergmann).
OK
So are you aware of any ARM platform implementing the ACPI EC?
I am not. Moreover, I'm not aware of any plans in that area.
Another thing worth noticing is that, global_lock is getting an unsigned long long value assigned to it in ec_parse_device() and this is what Arnd had to say about that:
"I think that's fine, it does this because the _GLP variable in ACPI is defined as an u64. And that's what happens on 32-bit architectures anyway."
This patch should go via GregKH, as the second patch has dependency on it.
V2->V3:
- Moved this out in a separate patch, so that it can be backported.
Lv, can you have a look at this, please?
drivers/acpi/ec_sys.c | 2 +- drivers/acpi/internal.h | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/acpi/ec_sys.c b/drivers/acpi/ec_sys.c index b4c216bab22b..bea8e425a8de 100644 --- a/drivers/acpi/ec_sys.c +++ b/drivers/acpi/ec_sys.c @@ -128,7 +128,7 @@ static int acpi_ec_add_debugfs(struct acpi_ec *ec, unsigned int ec_device_count) if (!debugfs_create_x32("gpe", 0444, dev_dir, (u32 *)&first_ec->gpe)) goto error; if (!debugfs_create_bool("use_global_lock", 0444, dev_dir,
(u32 *)&first_ec->global_lock))
&first_ec->global_lock))goto error;
if (write_support)
diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h index 9e426210c2a8..9db196de003c 100644 --- a/drivers/acpi/internal.h +++ b/drivers/acpi/internal.h @@ -138,7 +138,7 @@ struct acpi_ec { unsigned long gpe; unsigned long command_addr; unsigned long data_addr;
- unsigned long global_lock;
- u32 global_lock; unsigned long flags; unsigned long reference_count; struct mutex mutex;
If we really want to change, we may change everything here. gpe/command_addr/data_addr/global_lock. And IMO, if we really want to change global_lock, we should make it bool here.
Thanks and best regards -Lv
Thanks, Rafael