Merge branch 'for-6.15/amd_sfh' into for-linus

From: Mario Limonciello <mario.limonciello@amd.com>

Some platforms include a human presence detection (HPD) sensor. When
enabled and a user is detected a wake event will be emitted from the
sensor fusion hub that software can react to.

Example use cases are "wake from suspend on approach" or to "lock
when leaving".

This is currently enabled by default on supported systems, but users
can't control it. This essentially means that wake on approach is
enabled which is a really surprising behavior to users that don't
expect it.

Instead of defaulting to enabled add a sysfs knob that users can
use to enable the feature if desirable and set it to disabled by
default.

1 files changed, 15 insertions, 23 deletions

diff --git a/kernel/bpf/bpf_local_storage.c b/kernel/bpf/bpf_local_storage.c
index 7e6a0af0afc1..fa56c30833ff 100644
--- a/kernel/bpf/bpf_local_storage.c
+++ b/kernel/bpf/bpf_local_storage.c
@@ -81,9 +81,7 @@ bpf_selem_alloc(struct bpf_local_storage_map *smap, void *owner,
 		return NULL;
 
 	if (smap->bpf_ma) {
-		migrate_disable();
 		selem = bpf_mem_cache_alloc_flags(&smap->selem_ma, gfp_flags);
-		migrate_enable();
 		if (selem)
 			/* Keep the original bpf_map_kzalloc behavior
 			 * before started using the bpf_mem_cache_alloc.
@@ -174,17 +172,14 @@ static void bpf_local_storage_free(struct bpf_local_storage *local_storage,
 		return;
 	}
 
-	if (smap) {
-		migrate_disable();
+	if (smap)
 		bpf_mem_cache_free(&smap->storage_ma, local_storage);
-		migrate_enable();
-	} else {
+	else
 		/* smap could be NULL if the selem that triggered
 		 * this 'local_storage' creation had been long gone.
 		 * In this case, directly do call_rcu().
 		 */
 		call_rcu(&local_storage->rcu, bpf_local_storage_free_rcu);
-	}
 }
 
 /* rcu tasks trace callback for bpf_ma == false */
@@ -217,7 +212,10 @@ static void bpf_selem_free_rcu(struct rcu_head *rcu)
 	selem = container_of(rcu, struct bpf_local_storage_elem, rcu);
 	/* The bpf_local_storage_map_free will wait for rcu_barrier */
 	smap = rcu_dereference_check(SDATA(selem)->smap, 1);
+
+	migrate_disable();
 	bpf_obj_free_fields(smap->map.record, SDATA(selem)->data);
+	migrate_enable();
 	bpf_mem_cache_raw_free(selem);
 }
 
@@ -256,9 +254,7 @@ void bpf_selem_free(struct bpf_local_storage_elem *selem,
 		 * bpf_mem_cache_free will be able to reuse selem
 		 * immediately.
 		 */
-		migrate_disable();
 		bpf_mem_cache_free(&smap->selem_ma, selem);
-		migrate_enable();
 		return;
 	}
 
@@ -497,15 +493,11 @@ int bpf_local_storage_alloc(void *owner,
 	if (err)
 		return err;
 
-	if (smap->bpf_ma) {
-		migrate_disable();
+	if (smap->bpf_ma)
 		storage = bpf_mem_cache_alloc_flags(&smap->storage_ma, gfp_flags);
-		migrate_enable();
-	} else {
+	else
 		storage = bpf_map_kzalloc(&smap->map, sizeof(*storage),
 					  gfp_flags | __GFP_NOWARN);
-	}
-
 	if (!storage) {
 		err = -ENOMEM;
 		goto uncharge;
@@ -841,8 +833,12 @@ bpf_local_storage_map_alloc(union bpf_attr *attr,
 	smap->elem_size = offsetof(struct bpf_local_storage_elem,
 				   sdata.data[attr->value_size]);
 
-	smap->bpf_ma = bpf_ma;
-	if (bpf_ma) {
+	/* In PREEMPT_RT, kmalloc(GFP_ATOMIC) is still not safe in non
+	 * preemptible context. Thus, enforce all storages to use
+	 * bpf_mem_alloc when CONFIG_PREEMPT_RT is enabled.
+	 */
+	smap->bpf_ma = IS_ENABLED(CONFIG_PREEMPT_RT) ? true : bpf_ma;
+	if (smap->bpf_ma) {
 		err = bpf_mem_alloc_init(&smap->selem_ma, smap->elem_size, false);
 		if (err)
 			goto free_smap;
@@ -898,15 +894,11 @@ void bpf_local_storage_map_free(struct bpf_map *map,
 		while ((selem = hlist_entry_safe(
 				rcu_dereference_raw(hlist_first_rcu(&b->list)),
 				struct bpf_local_storage_elem, map_node))) {
-			if (busy_counter) {
-				migrate_disable();
+			if (busy_counter)
 				this_cpu_inc(*busy_counter);
-			}
 			bpf_selem_unlink(selem, true);
-			if (busy_counter) {
+			if (busy_counter)
 				this_cpu_dec(*busy_counter);
-				migrate_enable();
-			}
 			cond_resched_rcu();
 		}
 		rcu_read_unlock();