Hi Peter,
On Mon, 2018-07-09 at 15:54 +0200, Peter Zijlstra wrote:
On Mon, Jul 09, 2018 at 04:45:50PM +0300, Alexey Brodkin wrote:
diff --git a/drivers/base/devres.c b/drivers/base/devres.c index f98a097e73f2..d65327cb83c9 100644 --- a/drivers/base/devres.c +++ b/drivers/base/devres.c @@ -24,8 +24,12 @@ struct devres_node { struct devres { struct devres_node node;
- /* -- 3 pointers */
- unsigned long long data[]; /* guarantee ull alignment */
- /*
* data[] must be 64 bit aligned even on 32 bit architectures* because it might be accessed by instructions that require* aligned memory arguments such as atomic64_t.*/- u8 __aligned(8) data[];
};
From a quick reading in Documentation/driver-model/devres.txt this devres muck is supposed to be device memory, right?
atomics (as in atomic*_t) are not defined for use on mmio.
wth kind of code is relying on this?
It's Etnaviv (GPU/DRM) driver in etnaviv_gpu_platform_probe(), see https://elixir.bootlin.com/linux/latest/source/drivers/gpu/drm/etnaviv/etnav...: ---------------------->8--------------------- struct drm_gpu_scheduler { ... atomic64_t job_id_count; ... };
struct etnaviv_gpu { ... struct drm_gpu_scheduler sched; };
struct etnaviv_gpu *gpu;
gpu = devm_kzalloc(dev, sizeof(*gpu), GFP_KERNEL); ---------------------->8---------------------
-Alexey