x86/kprobes: Fix crash when probing CS CALL instructionsgrafted

When using eBPF to probe CS CALL instructions within a function,
a crash can be triggered.

The eBPF tool probes offset 257 of the __hrtimer_run_queues()
function:

<__hrtimer_run_queues+249>:  nopl   0x0(%rax,%rax,1)
<__hrtimer_run_queues+254>:  mov    %r14,%rdi
<__hrtimer_run_queues+257>:  cs call <__x86_indirect_thunk_r12>
<__hrtimer_run_queues+263>:  mov    %eax,%r12d
<__hrtimer_run_queues+266>:  xchg   %ax,%ax
<__hrtimer_run_queues+268>:  mov    %r13,%rdi

Which triggers this crash:

  BUG: unable to handle page fault for address: 00000000000f41c9
  #PF: supervisor write access in kernel mode
  #PF: error_code(0x0002) - not-present page
  PGD 0 P4D 0
  Oops: 0002 [#1] SMP NOPTI
  CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P
  RIP: 0010:__hrtimer_run_queues+0x106/0x230

Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is
at the 6th byte of the above CS CALL instruction. Since the CS CALL
instruction occupies 6 bytes, the exception occurred in the middle of that
call instruction.

The root cause is that when using eBPF tools to probe in the middle of a
function, a kprobe with INT3 is used as the underlying implementation.

During single-step emulation of the original CALL instruction,
int3_emulate_call() assumes that the probed CALL instruction is 5 bytes
long. However, the actual CS-prefixed CALL instruction occupies 6 bytes,
so it constructs an incorrect exception return address. When the CPU
returns from the kprobe handler, the next instruction to be executed is at
the address of the last byte of that CS CALL instruction. Coincidentally,
starting from that address, the CPU fetches and decodes a completely
different instruction, which ultimately triggers a kernel crash.

Fix the issue by using the actual instruction length obtained from
the instruction decoder when constructing the exception return
address, rather than relying on the hardcoded CALL_INSN_SIZE macro.

[ mingo: Refined the changelog ]

Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step")
Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Jinke Han <jinkehan@didiglobal.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000

1 files changed, 708 insertions, 0 deletions

diff --git a/net/mac80211/debugfs.c b/net/mac80211/debugfs.c
new file mode 100644
index 000000000..105653a16
--- /dev/null
+++ b/net/mac80211/debugfs.c
@@ -0,0 +1,708 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * mac80211 debugfs for wireless PHYs
+ *
+ * Copyright 2007	Johannes Berg <johannes@sipsolutions.net>
+ * Copyright 2013-2014  Intel Mobile Communications GmbH
+ * Copyright (C) 2018 - 2019, 2021-2025 Intel Corporation
+ */
+
+#include <linux/debugfs.h>
+#include <linux/rtnetlink.h>
+#include <linux/vmalloc.h>
+#include "ieee80211_i.h"
+#include "driver-ops.h"
+#include "rate.h"
+#include "debugfs.h"
+
+#define DEBUGFS_FORMAT_BUFFER_SIZE 100
+
+int mac80211_format_buffer(char __user *userbuf, size_t count,
+				  loff_t *ppos, char *fmt, ...)
+{
+	va_list args;
+	char buf[DEBUGFS_FORMAT_BUFFER_SIZE];
+	int res;
+
+	va_start(args, fmt);
+	res = vscnprintf(buf, sizeof(buf), fmt, args);
+	va_end(args);
+
+	return simple_read_from_buffer(userbuf, count, ppos, buf, res);
+}
+
+#define DEBUGFS_READONLY_FILE_FN(name, fmt, value...)			\
+static ssize_t name## _read(struct file *file, char __user *userbuf,	\
+			    size_t count, loff_t *ppos)			\
+{									\
+	struct ieee80211_local *local = file->private_data;		\
+									\
+	return mac80211_format_buffer(userbuf, count, ppos, 		\
+				      fmt "\n", ##value);		\
+}
+
+#define DEBUGFS_READONLY_FILE_OPS(name)			\
+static const struct debugfs_short_fops name## _ops = {				\
+	.read = name## _read,						\
+	.llseek = generic_file_llseek,					\
+};
+
+#define DEBUGFS_READONLY_FILE(name, fmt, value...)		\
+	DEBUGFS_READONLY_FILE_FN(name, fmt, value)		\
+	DEBUGFS_READONLY_FILE_OPS(name)
+
+#define DEBUGFS_ADD(name)						\
+	debugfs_create_file(#name, 0400, phyd, local, &name## _ops)
+
+#define DEBUGFS_ADD_MODE(name, mode)					\
+	debugfs_create_file(#name, mode, phyd, local, &name## _ops);
+
+
+DEBUGFS_READONLY_FILE(hw_conf, "%x",
+		      local->hw.conf.flags);
+DEBUGFS_READONLY_FILE(user_power, "%d",
+		      local->user_power_level);
+DEBUGFS_READONLY_FILE(power, "%d",
+		      local->hw.conf.power_level);
+DEBUGFS_READONLY_FILE(total_ps_buffered, "%d",
+		      local->total_ps_buffered);
+DEBUGFS_READONLY_FILE(wep_iv, "%#08x",
+		      local->wep_iv & 0xffffff);
+DEBUGFS_READONLY_FILE(rate_ctrl_alg, "%s",
+	local->rate_ctrl ? local->rate_ctrl->ops->name : "hw/driver");
+
+static ssize_t aqm_read(struct file *file,
+			char __user *user_buf,
+			size_t count,
+			loff_t *ppos)
+{
+	struct ieee80211_local *local = file->private_data;
+	struct fq *fq = &local->fq;
+	char buf[200];
+	int len = 0;
+
+	spin_lock_bh(&local->fq.lock);
+
+	len = scnprintf(buf, sizeof(buf),
+			"access name value\n"
+			"R fq_flows_cnt %u\n"
+			"R fq_backlog %u\n"
+			"R fq_overlimit %u\n"
+			"R fq_overmemory %u\n"
+			"R fq_collisions %u\n"
+			"R fq_memory_usage %u\n"
+			"RW fq_memory_limit %u\n"
+			"RW fq_limit %u\n"
+			"RW fq_quantum %u\n",
+			fq->flows_cnt,
+			fq->backlog,
+			fq->overmemory,
+			fq->overlimit,
+			fq->collisions,
+			fq->memory_usage,
+			fq->memory_limit,
+			fq->limit,
+			fq->quantum);
+
+	spin_unlock_bh(&local->fq.lock);
+
+	return simple_read_from_buffer(user_buf, count, ppos,
+				       buf, len);
+}
+
+static ssize_t aqm_write(struct file *file,
+			 const char __user *user_buf,
+			 size_t count,
+			 loff_t *ppos)
+{
+	struct ieee80211_local *local = file->private_data;
+	char buf[100];
+
+	if (count >= sizeof(buf))
+		return -EINVAL;
+
+	if (copy_from_user(buf, user_buf, count))
+		return -EFAULT;
+
+	if (count && buf[count - 1] == '\n')
+		buf[count - 1] = '\0';
+	else
+		buf[count] = '\0';
+
+	if (sscanf(buf, "fq_limit %u", &local->fq.limit) == 1)
+		return count;
+	else if (sscanf(buf, "fq_memory_limit %u", &local->fq.memory_limit) == 1)
+		return count;
+	else if (sscanf(buf, "fq_quantum %u", &local->fq.quantum) == 1)
+		return count;
+
+	return -EINVAL;
+}
+
+static const struct debugfs_short_fops aqm_ops = {
+	.write = aqm_write,
+	.read = aqm_read,
+	.llseek = default_llseek,
+};
+
+static ssize_t airtime_flags_read(struct file *file,
+				  char __user *user_buf,
+				  size_t count, loff_t *ppos)
+{
+	struct ieee80211_local *local = file->private_data;
+	char buf[128] = {}, *pos, *end;
+
+	pos = buf;
+	end = pos + sizeof(buf) - 1;
+
+	if (local->airtime_flags & AIRTIME_USE_TX)
+		pos += scnprintf(pos, end - pos, "AIRTIME_TX\t(%lx)\n",
+				 AIRTIME_USE_TX);
+	if (local->airtime_flags & AIRTIME_USE_RX)
+		pos += scnprintf(pos, end - pos, "AIRTIME_RX\t(%lx)\n",
+				 AIRTIME_USE_RX);
+
+	return simple_read_from_buffer(user_buf, count, ppos, buf,
+				       strlen(buf));
+}
+
+static ssize_t airtime_flags_write(struct file *file,
+				   const char __user *user_buf,
+				   size_t count, loff_t *ppos)
+{
+	struct ieee80211_local *local = file->private_data;
+	int ret;
+
+	ret = kstrtou16_from_user(user_buf, count, 0, &local->airtime_flags);
+	return ret ? : count;
+}
+
+static const struct debugfs_short_fops airtime_flags_ops = {
+	.write = airtime_flags_write,
+	.read = airtime_flags_read,
+	.llseek = default_llseek,
+};
+
+static ssize_t aql_pending_read(struct file *file,
+				char __user *user_buf,
+				size_t count, loff_t *ppos)
+{
+	struct ieee80211_local *local = file->private_data;
+	char buf[400];
+	int len = 0;
+
+	len = scnprintf(buf, sizeof(buf),
+			"AC     AQL pending\n"
+			"VO     %u us\n"
+			"VI     %u us\n"
+			"BE     %u us\n"
+			"BK     %u us\n"
+			"MC     %u us\n"
+			"total  %u us\n",
+			atomic_read(&local->aql_ac_pending_airtime[IEEE80211_AC_VO]),
+			atomic_read(&local->aql_ac_pending_airtime[IEEE80211_AC_VI]),
+			atomic_read(&local->aql_ac_pending_airtime[IEEE80211_AC_BE]),
+			atomic_read(&local->aql_ac_pending_airtime[IEEE80211_AC_BK]),
+			atomic_read(&local->aql_mc_pending_airtime),
+			atomic_read(&local->aql_total_pending_airtime));
+	return simple_read_from_buffer(user_buf, count, ppos,
+				       buf, len);
+}
+
+static const struct debugfs_short_fops aql_pending_ops = {
+	.read = aql_pending_read,
+	.llseek = default_llseek,
+};
+
+static ssize_t aql_txq_limit_read(struct file *file,
+				  char __user *user_buf,
+				  size_t count,
+				  loff_t *ppos)
+{
+	struct ieee80211_local *local = file->private_data;
+	char buf[400];
+	int len = 0;
+
+	len = scnprintf(buf, sizeof(buf),
+			"AC	AQL limit low	AQL limit high\n"
+			"VO	%u		%u\n"
+			"VI	%u		%u\n"
+			"BE	%u		%u\n"
+			"BK	%u		%u\n"
+			"MC	%u\n",
+			local->aql_txq_limit_low[IEEE80211_AC_VO],
+			local->aql_txq_limit_high[IEEE80211_AC_VO],
+			local->aql_txq_limit_low[IEEE80211_AC_VI],
+			local->aql_txq_limit_high[IEEE80211_AC_VI],
+			local->aql_txq_limit_low[IEEE80211_AC_BE],
+			local->aql_txq_limit_high[IEEE80211_AC_BE],
+			local->aql_txq_limit_low[IEEE80211_AC_BK],
+			local->aql_txq_limit_high[IEEE80211_AC_BK],
+			local->aql_txq_limit_mc);
+	return simple_read_from_buffer(user_buf, count, ppos,
+				       buf, len);
+}
+
+static ssize_t aql_txq_limit_write(struct file *file,
+				   const char __user *user_buf,
+				   size_t count,
+				   loff_t *ppos)
+{
+	struct ieee80211_local *local = file->private_data;
+	char buf[100];
+	u32 ac, q_limit_low, q_limit_high, q_limit_low_old, q_limit_high_old;
+	struct sta_info *sta;
+
+	if (count >= sizeof(buf))
+		return -EINVAL;
+
+	if (copy_from_user(buf, user_buf, count))
+		return -EFAULT;
+
+	if (count && buf[count - 1] == '\n')
+		buf[count - 1] = '\0';
+	else
+		buf[count] = '\0';
+
+	if (sscanf(buf, "mcast %u", &q_limit_low) == 1) {
+		local->aql_txq_limit_mc = q_limit_low;
+		return count;
+	}
+
+	if (sscanf(buf, "%u %u %u", &ac, &q_limit_low, &q_limit_high) != 3)
+		return -EINVAL;
+
+	if (ac >= IEEE80211_NUM_ACS)
+		return -EINVAL;
+
+	q_limit_low_old = local->aql_txq_limit_low[ac];
+	q_limit_high_old = local->aql_txq_limit_high[ac];
+
+	guard(wiphy)(local->hw.wiphy);
+
+	local->aql_txq_limit_low[ac] = q_limit_low;
+	local->aql_txq_limit_high[ac] = q_limit_high;
+
+	list_for_each_entry(sta, &local->sta_list, list) {
+		/* If a sta has customized queue limits, keep it */
+		if (sta->airtime[ac].aql_limit_low == q_limit_low_old &&
+		    sta->airtime[ac].aql_limit_high == q_limit_high_old) {
+			sta->airtime[ac].aql_limit_low = q_limit_low;
+			sta->airtime[ac].aql_limit_high = q_limit_high;
+		}
+	}
+
+	return count;
+}
+
+static const struct debugfs_short_fops aql_txq_limit_ops = {
+	.write = aql_txq_limit_write,
+	.read = aql_txq_limit_read,
+	.llseek = default_llseek,
+};
+
+static ssize_t aql_enable_read(struct file *file, char __user *user_buf,
+			       size_t count, loff_t *ppos)
+{
+	char buf[3];
+	int len;
+
+	len = scnprintf(buf, sizeof(buf), "%d\n",
+			!static_key_false(&aql_disable.key));
+
+	return simple_read_from_buffer(user_buf, count, ppos, buf, len);
+}
+
+static ssize_t aql_enable_write(struct file *file, const char __user *user_buf,
+				size_t count, loff_t *ppos)
+{
+	bool val;
+	int ret;
+
+	ret = kstrtobool_from_user(user_buf, count, &val);
+	if (unlikely(ret))
+		return ret;
+
+	if (val)
+		static_branch_disable(&aql_disable);
+	else
+		static_branch_enable(&aql_disable);
+
+	return count;
+}
+
+static const struct debugfs_short_fops aql_enable_ops = {
+	.write = aql_enable_write,
+	.read = aql_enable_read,
+	.llseek = default_llseek,
+};
+
+static ssize_t force_tx_status_read(struct file *file,
+				    char __user *user_buf,
+				    size_t count,
+				    loff_t *ppos)
+{
+	struct ieee80211_local *local = file->private_data;
+	char buf[3];
+	int len = 0;
+
+	len = scnprintf(buf, sizeof(buf), "%d\n", (int)local->force_tx_status);
+
+	return simple_read_from_buffer(user_buf, count, ppos,
+				       buf, len);
+}
+
+static ssize_t force_tx_status_write(struct file *file,
+				     const char __user *user_buf,
+				     size_t count,
+				     loff_t *ppos)
+{
+	struct ieee80211_local *local = file->private_data;
+	bool val;
+	int ret;
+
+	ret = kstrtobool_from_user(user_buf, count, &val);
+	if (unlikely(ret))
+		return ret;
+
+	local->force_tx_status = val;
+	return count;
+}
+
+static const struct debugfs_short_fops force_tx_status_ops = {
+	.write = force_tx_status_write,
+	.read = force_tx_status_read,
+	.llseek = default_llseek,
+};
+
+#ifdef CONFIG_PM
+static ssize_t reset_write(struct file *file, const char __user *user_buf,
+			   size_t count, loff_t *ppos)
+{
+	struct ieee80211_local *local = file->private_data;
+	int ret;
+
+	rtnl_lock();
+	wiphy_lock(local->hw.wiphy);
+	__ieee80211_suspend(&local->hw, NULL);
+	ret = __ieee80211_resume(&local->hw);
+	wiphy_unlock(local->hw.wiphy);
+
+	if (ret)
+		cfg80211_shutdown_all_interfaces(local->hw.wiphy);
+
+	rtnl_unlock();
+
+	return count;
+}
+
+static const struct debugfs_short_fops reset_ops = {
+	.write = reset_write,
+	.llseek = noop_llseek,
+};
+#endif
+
+static const char *hw_flag_names[] = {
+#define FLAG(F)	[IEEE80211_HW_##F] = #F
+	FLAG(HAS_RATE_CONTROL),
+	FLAG(RX_INCLUDES_FCS),
+	FLAG(HOST_BROADCAST_PS_BUFFERING),
+	FLAG(SIGNAL_UNSPEC),
+	FLAG(SIGNAL_DBM),
+	FLAG(NEED_DTIM_BEFORE_ASSOC),
+	FLAG(SPECTRUM_MGMT),
+	FLAG(AMPDU_AGGREGATION),
+	FLAG(SUPPORTS_PS),
+	FLAG(PS_NULLFUNC_STACK),
+	FLAG(SUPPORTS_DYNAMIC_PS),
+	FLAG(MFP_CAPABLE),
+	FLAG(WANT_MONITOR_VIF),
+	FLAG(NO_VIRTUAL_MONITOR),
+	FLAG(NO_AUTO_VIF),
+	FLAG(SW_CRYPTO_CONTROL),
+	FLAG(SUPPORT_FAST_XMIT),
+	FLAG(REPORTS_TX_ACK_STATUS),
+	FLAG(CONNECTION_MONITOR),
+	FLAG(QUEUE_CONTROL),
+	FLAG(SUPPORTS_PER_STA_GTK),
+	FLAG(AP_LINK_PS),
+	FLAG(TX_AMPDU_SETUP_IN_HW),
+	FLAG(SUPPORTS_RC_TABLE),
+	FLAG(P2P_DEV_ADDR_FOR_INTF),
+	FLAG(TIMING_BEACON_ONLY),
+	FLAG(SUPPORTS_HT_CCK_RATES),
+	FLAG(CHANCTX_STA_CSA),
+	FLAG(SUPPORTS_CLONED_SKBS),
+	FLAG(SINGLE_SCAN_ON_ALL_BANDS),
+	FLAG(TDLS_WIDER_BW),
+	FLAG(SUPPORTS_AMSDU_IN_AMPDU),
+	FLAG(BEACON_TX_STATUS),
+	FLAG(NEEDS_UNIQUE_STA_ADDR),
+	FLAG(SUPPORTS_REORDERING_BUFFER),
+	FLAG(USES_RSS),
+	FLAG(TX_AMSDU),
+	FLAG(TX_FRAG_LIST),
+	FLAG(REPORTS_LOW_ACK),
+	FLAG(SUPPORTS_TX_FRAG),
+	FLAG(SUPPORTS_TDLS_BUFFER_STA),
+	FLAG(DOESNT_SUPPORT_QOS_NDP),
+	FLAG(BUFF_MMPDU_TXQ),
+	FLAG(SUPPORTS_VHT_EXT_NSS_BW),
+	FLAG(STA_MMPDU_TXQ),
+	FLAG(TX_STATUS_NO_AMPDU_LEN),
+	FLAG(SUPPORTS_MULTI_BSSID),
+	FLAG(SUPPORTS_ONLY_HE_MULTI_BSSID),
+	FLAG(AMPDU_KEYBORDER_SUPPORT),
+	FLAG(SUPPORTS_TX_ENCAP_OFFLOAD),
+	FLAG(SUPPORTS_RX_DECAP_OFFLOAD),
+	FLAG(SUPPORTS_CONC_MON_RX_DECAP),
+	FLAG(DETECTS_COLOR_COLLISION),
+	FLAG(MLO_MCAST_MULTI_LINK_TX),
+	FLAG(DISALLOW_PUNCTURING),
+	FLAG(HANDLES_QUIET_CSA),
+	FLAG(STRICT),
+	FLAG(SUPPORTS_NDP_BLOCKACK),
+#undef FLAG
+};
+
+static ssize_t hwflags_read(struct file *file, char __user *user_buf,
+			    size_t count, loff_t *ppos)
+{
+	struct ieee80211_local *local = file->private_data;
+	size_t bufsz = 30 * NUM_IEEE80211_HW_FLAGS;
+	char *buf = kzalloc(bufsz, GFP_KERNEL);
+	char *pos = buf, *end = buf + bufsz - 1;
+	ssize_t rv;
+	int i;
+
+	if (!buf)
+		return -ENOMEM;
+
+	/* fail compilation if somebody adds or removes
+	 * a flag without updating the name array above
+	 */
+	BUILD_BUG_ON(ARRAY_SIZE(hw_flag_names) != NUM_IEEE80211_HW_FLAGS);
+
+	for (i = 0; i < NUM_IEEE80211_HW_FLAGS; i++) {
+		if (test_bit(i, local->hw.flags))
+			pos += scnprintf(pos, end - pos, "%s\n",
+					 hw_flag_names[i]);
+	}
+
+	rv = simple_read_from_buffer(user_buf, count, ppos, buf, strlen(buf));
+	kfree(buf);
+	return rv;
+}
+
+static ssize_t hwflags_write(struct file *file, const char __user *user_buf,
+			     size_t count, loff_t *ppos)
+{
+	struct ieee80211_local *local = file->private_data;
+	char buf[100];
+	int val;
+
+	if (count >= sizeof(buf))
+		return -EINVAL;
+
+	if (copy_from_user(buf, user_buf, count))
+		return -EFAULT;
+
+	if (count && buf[count - 1] == '\n')
+		buf[count - 1] = '\0';
+	else
+		buf[count] = '\0';
+
+	if (sscanf(buf, "strict=%d", &val) == 1) {
+		switch (val) {
+		case 0:
+			ieee80211_hw_set(&local->hw, STRICT);
+			return count;
+		case 1:
+			__clear_bit(IEEE80211_HW_STRICT, local->hw.flags);
+			return count;
+		default:
+			return -EINVAL;
+		}
+	}
+
+	return -EINVAL;
+}
+
+static const struct file_operations hwflags_ops = {
+	.open = simple_open,
+	.read = hwflags_read,
+	.write = hwflags_write,
+};
+
+static ssize_t misc_read(struct file *file, char __user *user_buf,
+			 size_t count, loff_t *ppos)
+{
+	struct ieee80211_local *local = file->private_data;
+	/* Max len of each line is 16 characters, plus 9 for 'pending:\n' */
+	size_t bufsz = IEEE80211_MAX_QUEUES * 16 + 9;
+	char *buf;
+	char *pos, *end;
+	ssize_t rv;
+	int i;
+	int ln;
+
+	buf = kzalloc(bufsz, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	pos = buf;
+	end = buf + bufsz - 1;
+
+	pos += scnprintf(pos, end - pos, "pending:\n");
+
+	for (i = 0; i < IEEE80211_MAX_QUEUES; i++) {
+		ln = skb_queue_len(&local->pending[i]);
+		pos += scnprintf(pos, end - pos, "[%i] %d\n",
+				 i, ln);
+	}
+
+	rv = simple_read_from_buffer(user_buf, count, ppos, buf, strlen(buf));
+	kfree(buf);
+	return rv;
+}
+
+static ssize_t queues_read(struct file *file, char __user *user_buf,
+			   size_t count, loff_t *ppos)
+{
+	struct ieee80211_local *local = file->private_data;
+	unsigned long flags;
+	char buf[IEEE80211_MAX_QUEUES * 20];
+	int q, res = 0;
+
+	spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
+	for (q = 0; q < local->hw.queues; q++)
+		res += sprintf(buf + res, "%02d: %#.8lx/%d\n", q,
+				local->queue_stop_reasons[q],
+				skb_queue_len(&local->pending[q]));
+	spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags);
+
+	return simple_read_from_buffer(user_buf, count, ppos, buf, res);
+}
+
+DEBUGFS_READONLY_FILE_OPS(queues);
+DEBUGFS_READONLY_FILE_OPS(misc);
+
+/* statistics stuff */
+
+static ssize_t format_devstat_counter(struct ieee80211_local *local,
+	char __user *userbuf,
+	size_t count, loff_t *ppos,
+	int (*printvalue)(struct ieee80211_low_level_stats *stats, char *buf,
+			  int buflen))
+{
+	struct ieee80211_low_level_stats stats;
+	char buf[20];
+	int res;
+
+	wiphy_lock(local->hw.wiphy);
+	res = drv_get_stats(local, &stats);
+	wiphy_unlock(local->hw.wiphy);
+	if (res)
+		return res;
+	res = printvalue(&stats, buf, sizeof(buf));
+	return simple_read_from_buffer(userbuf, count, ppos, buf, res);
+}
+
+#define DEBUGFS_DEVSTATS_FILE(name)					\
+static int print_devstats_##name(struct ieee80211_low_level_stats *stats,\
+				 char *buf, int buflen)			\
+{									\
+	return scnprintf(buf, buflen, "%u\n", stats->name);		\
+}									\
+static ssize_t stats_ ##name## _read(struct file *file,			\
+				     char __user *userbuf,		\
+				     size_t count, loff_t *ppos)	\
+{									\
+	return format_devstat_counter(file->private_data,		\
+				      userbuf,				\
+				      count,				\
+				      ppos,				\
+				      print_devstats_##name);		\
+}									\
+									\
+static const struct debugfs_short_fops stats_ ##name## _ops = {			\
+	.read = stats_ ##name## _read,					\
+	.llseek = generic_file_llseek,					\
+};
+
+#ifdef CONFIG_MAC80211_DEBUG_COUNTERS
+#define DEBUGFS_STATS_ADD(name)					\
+	debugfs_create_u32(#name, 0400, statsd, &local->name);
+#endif
+#define DEBUGFS_DEVSTATS_ADD(name)					\
+	debugfs_create_file(#name, 0400, statsd, local, &stats_ ##name## _ops);
+
+DEBUGFS_DEVSTATS_FILE(dot11ACKFailureCount);
+DEBUGFS_DEVSTATS_FILE(dot11RTSFailureCount);
+DEBUGFS_DEVSTATS_FILE(dot11FCSErrorCount);
+DEBUGFS_DEVSTATS_FILE(dot11RTSSuccessCount);
+
+void debugfs_hw_add(struct ieee80211_local *local)
+{
+	struct dentry *phyd = local->hw.wiphy->debugfsdir;
+	struct dentry *statsd;
+
+	if (!phyd)
+		return;
+
+	local->debugfs.keys = debugfs_create_dir("keys", phyd);
+
+	DEBUGFS_ADD(total_ps_buffered);
+	DEBUGFS_ADD(wep_iv);
+	DEBUGFS_ADD(rate_ctrl_alg);
+	DEBUGFS_ADD(queues);
+	DEBUGFS_ADD(misc);
+#ifdef CONFIG_PM
+	DEBUGFS_ADD_MODE(reset, 0200);
+#endif
+	DEBUGFS_ADD_MODE(hwflags, 0600);
+	DEBUGFS_ADD(user_power);
+	DEBUGFS_ADD(power);
+	DEBUGFS_ADD(hw_conf);
+	DEBUGFS_ADD_MODE(force_tx_status, 0600);
+	DEBUGFS_ADD_MODE(aql_enable, 0600);
+	DEBUGFS_ADD(aql_pending);
+	DEBUGFS_ADD_MODE(aqm, 0600);
+
+	DEBUGFS_ADD_MODE(airtime_flags, 0600);
+
+	DEBUGFS_ADD(aql_txq_limit);
+	debugfs_create_u32("aql_threshold", 0600,
+			   phyd, &local->aql_threshold);
+
+	statsd = debugfs_create_dir("statistics", phyd);
+
+#ifdef CONFIG_MAC80211_DEBUG_COUNTERS
+	DEBUGFS_STATS_ADD(dot11TransmittedFragmentCount);
+	DEBUGFS_STATS_ADD(dot11MulticastTransmittedFrameCount);
+	DEBUGFS_STATS_ADD(dot11FailedCount);
+	DEBUGFS_STATS_ADD(dot11RetryCount);
+	DEBUGFS_STATS_ADD(dot11MultipleRetryCount);
+	DEBUGFS_STATS_ADD(dot11FrameDuplicateCount);
+	DEBUGFS_STATS_ADD(dot11ReceivedFragmentCount);
+	DEBUGFS_STATS_ADD(dot11MulticastReceivedFrameCount);
+	DEBUGFS_STATS_ADD(dot11TransmittedFrameCount);
+	DEBUGFS_STATS_ADD(tx_handlers_queued);
+	DEBUGFS_STATS_ADD(tx_handlers_drop_wep);
+	DEBUGFS_STATS_ADD(tx_handlers_drop_not_assoc);
+	DEBUGFS_STATS_ADD(tx_handlers_drop_unauth_port);
+	DEBUGFS_STATS_ADD(rx_handlers_drop);
+	DEBUGFS_STATS_ADD(rx_handlers_queued);
+	DEBUGFS_STATS_ADD(rx_handlers_drop_nullfunc);
+	DEBUGFS_STATS_ADD(rx_handlers_drop_defrag);
+	DEBUGFS_STATS_ADD(tx_expand_skb_head);
+	DEBUGFS_STATS_ADD(tx_expand_skb_head_cloned);
+	DEBUGFS_STATS_ADD(rx_expand_skb_head_defrag);
+	DEBUGFS_STATS_ADD(rx_handlers_fragments);
+	DEBUGFS_STATS_ADD(tx_status_drop);
+#endif
+	DEBUGFS_DEVSTATS_ADD(dot11ACKFailureCount);
+	DEBUGFS_DEVSTATS_ADD(dot11RTSFailureCount);
+	DEBUGFS_DEVSTATS_ADD(dot11FCSErrorCount);
+	DEBUGFS_DEVSTATS_ADD(dot11RTSSuccessCount);
+}