bpf: mark a NULL kfunc argument precisegrafted

check_kfunc_arg() allows bpf_register_is_null() for nullable arguments
w/o marking the underlying scalar register precise. Hence a checkpoint
created on such a path would prune against arbitrary scalar value.

Fixes: 3bda08b63670 ("bpf: Allow NULL buffers in bpf_dynptr_slice(_rw)")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20260904-register-is-null-precise-fixes-v1-5-0f5a360ff15d@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

1 files changed, 94 insertions, 0 deletions

diff --git a/net/mac80211/wbrf.c b/net/mac80211/wbrf.c
new file mode 100644
index 000000000..478b34b81
--- /dev/null
+++ b/net/mac80211/wbrf.c
@@ -0,0 +1,94 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Wifi Band Exclusion Interface for WLAN
+ * Copyright (C) 2023 Advanced Micro Devices
+ * Copyright (C) 2025 Intel Corporation
+ *
+ */
+
+#include <linux/acpi_amd_wbrf.h>
+#include <linux/units.h>
+#include <net/cfg80211.h>
+#include "ieee80211_i.h"
+
+void ieee80211_check_wbrf_support(struct ieee80211_local *local)
+{
+	struct wiphy *wiphy = local->hw.wiphy;
+	struct device *dev;
+
+	if (!wiphy)
+		return;
+
+	dev = wiphy->dev.parent;
+	if (!dev)
+		return;
+
+	local->wbrf_supported = acpi_amd_wbrf_supported_producer(dev);
+}
+
+static void get_chan_freq_boundary(u32 center_freq, u32 bandwidth, u64 *start, u64 *end)
+{
+	bandwidth *= KHZ_PER_MHZ;
+	center_freq *= KHZ_PER_MHZ;
+
+	*start = center_freq - bandwidth / 2;
+	*end = center_freq + bandwidth / 2;
+
+	/* Frequency in Hz is expected */
+	*start = *start * HZ_PER_KHZ;
+	*end = *end * HZ_PER_KHZ;
+}
+
+static void get_ranges_from_chandef(struct cfg80211_chan_def *chandef,
+				    struct wbrf_ranges_in_out *ranges_in)
+{
+	u64 start_freq1, end_freq1;
+	u64 start_freq2, end_freq2;
+	int bandwidth;
+
+	bandwidth = cfg80211_chandef_get_width(chandef);
+
+	get_chan_freq_boundary(chandef->center_freq1, bandwidth, &start_freq1, &end_freq1);
+
+	ranges_in->band_list[0].start = start_freq1;
+	ranges_in->band_list[0].end = end_freq1;
+	ranges_in->num_of_ranges = 1;
+
+	if (chandef->width == NL80211_CHAN_WIDTH_80P80) {
+		get_chan_freq_boundary(chandef->center_freq2, bandwidth, &start_freq2, &end_freq2);
+
+		ranges_in->band_list[1].start = start_freq2;
+		ranges_in->band_list[1].end = end_freq2;
+		ranges_in->num_of_ranges++;
+	}
+}
+
+void ieee80211_add_wbrf(struct ieee80211_local *local, struct cfg80211_chan_def *chandef)
+{
+	struct wbrf_ranges_in_out ranges_in = {0};
+	struct device *dev;
+
+	if (!local->wbrf_supported)
+		return;
+
+	dev = local->hw.wiphy->dev.parent;
+
+	get_ranges_from_chandef(chandef, &ranges_in);
+
+	acpi_amd_wbrf_add_remove(dev, WBRF_RECORD_ADD, &ranges_in);
+}
+
+void ieee80211_remove_wbrf(struct ieee80211_local *local, struct cfg80211_chan_def *chandef)
+{
+	struct wbrf_ranges_in_out ranges_in = {0};
+	struct device *dev;
+
+	if (!local->wbrf_supported)
+		return;
+
+	dev = local->hw.wiphy->dev.parent;
+
+	get_ranges_from_chandef(chandef, &ranges_in);
+
+	acpi_amd_wbrf_add_remove(dev, WBRF_RECORD_REMOVE, &ranges_in);
+}