* [PATCH net-next v4 1/2] net: pse-pd: add devm_pse_poll_helper()
From: Carlo Szelinsky @ 2026-04-10 12:44 UTC (permalink / raw)
To: Oleksij Rempel, Kory Maincent
Cc: Andrew Lunn, David S . Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Krzysztof Kozlowski, Krzysztof Kozlowski,
Conor Dooley, Rob Herring, netdev, linux-kernel, linux-leds,
Carlo Szelinsky
In-Reply-To: <20260410124428.809943-1-github@szelinsky.de>
Extract the common event handling loop from pse_isr() into a shared
pse_handle_events() function, and add a generic poll-based alternative
to the IRQ path for PSE controllers that lack interrupt support or
have IRQ lines not wired on the board.
The new devm_pse_poll_helper() function sets up a delayed work that
periodically calls the driver's map_event callback to detect state
changes, feeding events into the existing ntf_fifo / pse_send_ntf_worker
notification pipeline. This reuses the same pse_irq_desc interface as
the IRQ path — the driver provides a map_event callback that populates
per-PI notification arrays.
The poll worker uses system_freezable_wq to avoid running during system
suspend when the underlying hardware (e.g. I2C bus) may be inaccessible.
Work cancellation on teardown is handled via devm_add_action_or_reset()
to ensure the delayed work is cancelled before poll_notifs is freed
by devres, avoiding a use-after-free when devm_pse_poll_helper() is
called after devm_pse_controller_register() (devres LIFO ordering).
The poll interval defaults to 500ms if not set by the driver, balancing
responsiveness against bus load (e.g. I2C).
Signed-off-by: Carlo Szelinsky <github@szelinsky.de>
---
drivers/net/pse-pd/pse_core.c | 164 +++++++++++++++++++++++++++-------
include/linux/pse-pd/pse.h | 12 +++
2 files changed, 146 insertions(+), 30 deletions(-)
diff --git a/drivers/net/pse-pd/pse_core.c b/drivers/net/pse-pd/pse_core.c
index 3beaaaeec9e1..f641a6fa087f 100644
--- a/drivers/net/pse-pd/pse_core.c
+++ b/drivers/net/pse-pd/pse_core.c
@@ -14,10 +14,18 @@
#include <linux/regulator/driver.h>
#include <linux/regulator/machine.h>
#include <linux/rtnetlink.h>
+#include <linux/workqueue.h>
#include <net/net_trackers.h>
#define PSE_PW_D_LIMIT INT_MAX
+/*
+ * Default poll interval for controllers without IRQ support.
+ * 500ms provides a reasonable trade-off between responsiveness
+ * (event detection, PD detection) and I2C bus utilization.
+ */
+#define PSE_DEFAULT_POLL_INTERVAL_MS 500
+
static DEFINE_MUTEX(pse_list_mutex);
static LIST_HEAD(pse_controller_list);
static DEFINE_XARRAY_ALLOC(pse_pw_d_map);
@@ -1238,66 +1246,103 @@ static int pse_set_config_isr(struct pse_controller_dev *pcdev, int id,
}
/**
- * pse_isr - IRQ handler for PSE
- * @irq: irq number
- * @data: pointer to user interrupt structure
+ * pse_handle_events - Process PSE events for all PIs
+ * @pcdev: a pointer to the PSE controller device
+ * @notifs: per-PI notification array
+ * @notifs_mask: bitmask of PIs with events
*
- * Return: irqreturn_t - status of IRQ
+ * Common event handling shared between IRQ and poll paths.
+ * Caller must hold pcdev->lock.
*/
-static irqreturn_t pse_isr(int irq, void *data)
+static void pse_handle_events(struct pse_controller_dev *pcdev,
+ unsigned long *notifs,
+ unsigned long notifs_mask)
{
- struct pse_controller_dev *pcdev;
- unsigned long notifs_mask = 0;
- struct pse_irq_desc *desc;
- struct pse_irq *h = data;
- int ret, i;
-
- desc = &h->desc;
- pcdev = h->pcdev;
-
- /* Clear notifs mask */
- memset(h->notifs, 0, pcdev->nr_lines * sizeof(*h->notifs));
- mutex_lock(&pcdev->lock);
- ret = desc->map_event(irq, pcdev, h->notifs, ¬ifs_mask);
- if (ret || !notifs_mask) {
- mutex_unlock(&pcdev->lock);
- return IRQ_NONE;
- }
+ int i;
for_each_set_bit(i, ¬ifs_mask, pcdev->nr_lines) {
- unsigned long notifs, rnotifs;
+ unsigned long pi_notifs, rnotifs;
struct pse_ntf ntf = {};
+ int ret;
/* Do nothing PI not described */
if (!pcdev->pi[i].rdev)
continue;
- notifs = h->notifs[i];
+ pi_notifs = notifs[i];
if (pse_pw_d_is_sw_pw_control(pcdev, pcdev->pi[i].pw_d)) {
- ret = pse_set_config_isr(pcdev, i, notifs);
+ ret = pse_set_config_isr(pcdev, i, pi_notifs);
if (ret)
- notifs |= ETHTOOL_PSE_EVENT_SW_PW_CONTROL_ERROR;
+ pi_notifs |= ETHTOOL_PSE_EVENT_SW_PW_CONTROL_ERROR;
}
- dev_dbg(h->pcdev->dev,
- "Sending PSE notification EVT 0x%lx\n", notifs);
+ dev_dbg(pcdev->dev,
+ "Sending PSE notification EVT 0x%lx\n", pi_notifs);
- ntf.notifs = notifs;
+ ntf.notifs = pi_notifs;
ntf.id = i;
kfifo_in_spinlocked(&pcdev->ntf_fifo, &ntf, 1,
&pcdev->ntf_fifo_lock);
schedule_work(&pcdev->ntf_work);
- rnotifs = pse_to_regulator_notifs(notifs);
+ rnotifs = pse_to_regulator_notifs(pi_notifs);
regulator_notifier_call_chain(pcdev->pi[i].rdev, rnotifs,
NULL);
}
+}
+
+/**
+ * pse_isr - IRQ handler for PSE
+ * @irq: irq number
+ * @data: pointer to user interrupt structure
+ *
+ * Return: irqreturn_t - status of IRQ
+ */
+static irqreturn_t pse_isr(int irq, void *data)
+{
+ struct pse_controller_dev *pcdev;
+ unsigned long notifs_mask = 0;
+ struct pse_irq *h = data;
+ int ret;
+ pcdev = h->pcdev;
+
+ /* Clear notifs mask */
+ memset(h->notifs, 0, pcdev->nr_lines * sizeof(*h->notifs));
+ mutex_lock(&pcdev->lock);
+ ret = h->desc.map_event(irq, pcdev, h->notifs, ¬ifs_mask);
+ if (ret || !notifs_mask) {
+ mutex_unlock(&pcdev->lock);
+ return IRQ_NONE;
+ }
+
+ pse_handle_events(pcdev, h->notifs, notifs_mask);
mutex_unlock(&pcdev->lock);
return IRQ_HANDLED;
}
+static void pse_poll_worker(struct work_struct *work)
+{
+ struct pse_controller_dev *pcdev =
+ container_of(work, struct pse_controller_dev,
+ poll_work.work);
+ unsigned long notifs_mask = 0;
+ int ret;
+
+ memset(pcdev->poll_notifs, 0,
+ pcdev->nr_lines * sizeof(*pcdev->poll_notifs));
+ mutex_lock(&pcdev->lock);
+ ret = pcdev->poll_desc.map_event(0, pcdev, pcdev->poll_notifs,
+ ¬ifs_mask);
+ if (!ret && notifs_mask)
+ pse_handle_events(pcdev, pcdev->poll_notifs, notifs_mask);
+ mutex_unlock(&pcdev->lock);
+
+ queue_delayed_work(system_freezable_wq, &pcdev->poll_work,
+ msecs_to_jiffies(pcdev->poll_interval_ms));
+}
+
/**
* devm_pse_irq_helper - Register IRQ based PSE event notifier
* @pcdev: a pointer to the PSE
@@ -1351,6 +1396,65 @@ int devm_pse_irq_helper(struct pse_controller_dev *pcdev, int irq,
}
EXPORT_SYMBOL_GPL(devm_pse_irq_helper);
+static void pse_poll_cancel(void *data)
+{
+ struct pse_controller_dev *pcdev = data;
+
+ cancel_delayed_work_sync(&pcdev->poll_work);
+}
+
+/**
+ * devm_pse_poll_helper - Register poll-based PSE event notifier
+ * @pcdev: a pointer to the PSE controller device
+ * @d: PSE event description (uses same pse_irq_desc as IRQ path)
+ *
+ * For PSE controllers without IRQ support or with IRQ not wired. Sets
+ * up a delayed work that periodically calls the driver's map_event
+ * callback to detect state changes, feeding events into the standard
+ * notification pipeline.
+ *
+ * The poll worker uses system_freezable_wq to ensure it does not run
+ * during system suspend while the hardware may be inaccessible.
+ *
+ * Return: 0 on success and errno on failure
+ */
+int devm_pse_poll_helper(struct pse_controller_dev *pcdev,
+ const struct pse_irq_desc *d)
+{
+ struct device *dev = pcdev->dev;
+ int ret;
+
+ if (!d || !d->map_event || !d->name)
+ return -EINVAL;
+
+ pcdev->poll_desc = *d;
+ pcdev->poll_notifs = devm_kcalloc(dev, pcdev->nr_lines,
+ sizeof(*pcdev->poll_notifs),
+ GFP_KERNEL);
+ if (!pcdev->poll_notifs)
+ return -ENOMEM;
+
+ if (!pcdev->poll_interval_ms)
+ pcdev->poll_interval_ms = PSE_DEFAULT_POLL_INTERVAL_MS;
+
+ INIT_DELAYED_WORK(&pcdev->poll_work, pse_poll_worker);
+ pcdev->polling = true;
+
+ /* Register devm action to cancel poll work before poll_notifs is
+ * freed by devres. This ensures correct teardown ordering since
+ * devm_pse_poll_helper() is called after devm_pse_controller_register().
+ */
+ ret = devm_add_action_or_reset(dev, pse_poll_cancel, pcdev);
+ if (ret)
+ return ret;
+
+ queue_delayed_work(system_freezable_wq, &pcdev->poll_work,
+ msecs_to_jiffies(pcdev->poll_interval_ms));
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(devm_pse_poll_helper);
+
/* PSE control section */
static void __pse_control_release(struct kref *kref)
diff --git a/include/linux/pse-pd/pse.h b/include/linux/pse-pd/pse.h
index 4e5696cfade7..44d5d10e239d 100644
--- a/include/linux/pse-pd/pse.h
+++ b/include/linux/pse-pd/pse.h
@@ -292,6 +292,11 @@ struct pse_ntf {
* @pi: table of PSE PIs described in this controller device
* @no_of_pse_pi: flag set if the pse_pis devicetree node is not used
* @irq: PSE interrupt
+ * @polling: flag indicating poll-based event detection is active
+ * @poll_interval_ms: poll interval in milliseconds
+ * @poll_work: delayed work for poll-based event detection
+ * @poll_desc: copy of the driver's event descriptor for polling
+ * @poll_notifs: per-PI notification scratch space for poll worker
* @pis_prio_max: Maximum value allowed for the PSE PIs priority
* @supp_budget_eval_strategies: budget evaluation strategies supported
* by the PSE
@@ -312,6 +317,11 @@ struct pse_controller_dev {
struct pse_pi *pi;
bool no_of_pse_pi;
int irq;
+ bool polling;
+ unsigned int poll_interval_ms;
+ struct delayed_work poll_work;
+ struct pse_irq_desc poll_desc;
+ unsigned long *poll_notifs;
unsigned int pis_prio_max;
u32 supp_budget_eval_strategies;
struct work_struct ntf_work;
@@ -345,6 +355,8 @@ int devm_pse_controller_register(struct device *dev,
struct pse_controller_dev *pcdev);
int devm_pse_irq_helper(struct pse_controller_dev *pcdev, int irq,
int irq_flags, const struct pse_irq_desc *d);
+int devm_pse_poll_helper(struct pse_controller_dev *pcdev,
+ const struct pse_irq_desc *d);
struct pse_control *of_pse_control_get(struct device_node *node,
struct phy_device *phydev);
--
2.43.0
^ permalink raw reply related
* [PATCH net-next v4 0/2] net: pse-pd: add poll path and LED trigger support
From: Carlo Szelinsky @ 2026-04-10 12:44 UTC (permalink / raw)
To: Oleksij Rempel, Kory Maincent
Cc: Andrew Lunn, David S . Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Krzysztof Kozlowski, Krzysztof Kozlowski,
Conor Dooley, Rob Herring, netdev, linux-kernel, linux-leds,
Carlo Szelinsky
Thanks to Kory, Oleksij, Krzysztof and Andrew for all the helpful
feedback on earlier versions - really appreciate the time you put
into reviewing this.
This series adds poll-based event detection and LED trigger support
to the PSE core subsystem.
Patch 1 introduces the poll path independently of LED support,
so it can be tested in isolation on boards with and without IRQ
configured.
Patch 2 adds LED triggers that hook into the shared event handling
path introduced by patch 1.
Note: pse_handle_events() and the existing pse_isr() pass notifs_mask
as a single unsigned long, which limits the bitmask to BITS_PER_LONG
PI lines. This is a pre-existing constraint in the IRQ path and is
sufficient for all current PSE controllers (max 48 ports vs 64-bit
unsigned long), but may need to be converted to DECLARE_BITMAP() if
future hardware exceeds this limit.
Changes since v3:
- Dropped the dt-bindings poll-interval-ms patch: the poll interval
is a driver decision, not a hardware property (Krzysztof)
- Removed of_property_read_u32() for poll-interval-ms from
devm_pse_poll_helper(); the 500ms default is now hardcoded but
drivers can override pcdev->poll_interval_ms before calling the
helper
- Rebased on net-next/main
Changes since v2:
- Based on net-next/main, added net-next subject prefix
- Added --base tree information
- Added CC for devicetree list and DT maintainers
- Collected Reviewed-by from Kory Maincent on patch 1/3
- Fixed build error when CONFIG_LEDS_TRIGGERS is disabled:
moved LED registration before list_add(), removing the
pcdev->pi_led_trigs = NULL assignment on conditionally
compiled struct member (reported by kernel test robot)
- Fixed use-after-free on device unbind: poll work is now
cancelled via devm_add_action_or_reset() to ensure correct
devres teardown ordering (poll_work cancelled before
poll_notifs is freed)
- Used system_freezable_wq for poll worker to prevent hardware
access during system suspend
- Added PoDL power status and admin state checks to LED triggers
so they work for both C33 and PoDL controller types
- Used dev_name(dev) for LED trigger names to ensure uniqueness
across multiple PSE controllers (of_node->name can be generic)
- Added initial LED state query at registration so already-active
ports are reflected immediately
- Added pse_led_update() calls in regulator enable/disable paths
so ethtool admin state changes are reflected in LEDs
- Moved LED trigger registration before list_add() to prevent
race where IRQ/poll could invoke pse_led_update() on partially
initialized triggers
Changes since v1:
- Split single patch into 3 separate patches
- Extracted pse_handle_events() and devm_pse_poll_helper() as a
standalone poll path (patches 1-2), testable without LED code
- Added DT binding for poll-interval-ms as a separate patch
- Renamed led-poll-interval-ms to poll-interval-ms for generic use
- Fire LED triggers from the notification path rather than a
separate poll loop
Tested on Realtek RTL9303 with HS104 PoE chip, poll path only
(without IRQ configured). Verified PD connect/disconnect notifications
and LED trigger state changes.
Link: https://lore.kernel.org/all/20260329153124.2823980-1-github@szelinsky.de/
Link: https://lore.kernel.org/all/20260323201225.1836561-1-github@szelinsky.de/
Link: https://lore.kernel.org/all/20260314235916.2391678-1-github@szelinsky.de/
Carlo Szelinsky (2):
net: pse-pd: add devm_pse_poll_helper()
net: pse-pd: add LED trigger support via notification path
drivers/net/pse-pd/pse_core.c | 296 ++++++++++++++++++++++++++++++----
include/linux/pse-pd/pse.h | 34 ++++
2 files changed, 299 insertions(+), 31 deletions(-)
base-commit: b3e69fc3196fc421e26196e7792f17b0463edc6f
--
2.43.0
^ permalink raw reply
* Re: [PATCH net-next v3 0/4] net: move .getsockopt away from __user buffers
From: Breno Leitao @ 2026-04-10 12:29 UTC (permalink / raw)
To: David Laight
Cc: David S. Miller, Eric Dumazet, Jakub Kicinski, Paolo Abeni,
Simon Horman, Kuniyuki Iwashima, Willem de Bruijn, metze, axboe,
Stanislav Fomichev, io-uring, bpf, netdev, Linus Torvalds,
linux-kernel, kernel-team
In-Reply-To: <20260408195640.324ee932@pumpkin>
On Wed, Apr 08, 2026 at 07:56:40PM +0100, David Laight wrote:
> On Wed, 8 Apr 2026 06:52:54 -0700
> Breno Leitao <leitao@debian.org> wrote:
>
> > Hello David,
> >
> > On Wed, Apr 08, 2026 at 12:26:53PM +0100, David Laight wrote:
> > > On Wed, 08 Apr 2026 03:30:28 -0700
> > > Breno Leitao <leitao@debian.org> wrote:
> > >
> > > > Currently, the .getsockopt callback requires __user pointers:
> > > >
> > > > int (*getsockopt)(struct socket *sock, int level,
> > > > int optname, char __user *optval, int __user *optlen);
> > > >
> > > > This prevents kernel callers (io_uring, BPF) from using getsockopt on
> > > > levels other than SOL_SOCKET, since they pass kernel pointers.
> > > >
> > > > Following Linus' suggestion [0], this series introduces sockopt_t, a
> > > > type-safe wrapper around iov_iter, and a getsockopt_iter callback that
> > > > works with both user and kernel buffers. AF_PACKET and CAN raw are
> > > > converted as initial users, with selftests covering the trickiest
> > > > conversion patterns.
> > >
> > > What are you doing about the cases where 'optlen' is a complete lie?
> >
> > Is this incorrect optlen originating from userspace, and getting into
> > the .getsockopt callbacks?
>
> Look at tcp_ao_copy_mptks_to_user() in net/ipv4/tcp_ao.c
> This isn't 'old code' it was added in 2023.
>
> Basically what is being transferred is an array and 'optlen' is the
> size of one element.
> The number of elements is in the first one.
Thank you for pointing this out. I now understand the issue you're raising.
The problem is that optlen doesn't represent the full buffer length. Instead:
optlen = per-element struct size (stride)
actual buffer length = optlen * nkeys (where nkeys comes from optval[0])
For handling these cases, I can think of several approaches:
1) Dynamically resize the iter once the actual buffer size is discovered:
int sockopt_set_buflen(sockopt_t *opt, size_t new_len)
{
if (!opt->legacy) /* Following Stefan's suggestion */
return -EINVAL;
/* Re-initialize iter with the actual buffer size.
* For ubuf: same base pointer, updated count.
* For kvec: same iov_base, updated iov_len + re-init.
*/
}
This allows legacy protocols to adjust the iov_iter later, mirroring
current behavior. Note that this doesn't worsen the existing
situation—currently, the current code is like having iov_iter length is
set to INT_MAX, given the callback can read/write to any location based
on that __user pointer.
2) Use a special legacy callback path, as proposed by Stefan.
3) Store base pointers in sockopt_t and defer iter initialization for
legacy callbacks:
static int tcp_ao_copy_mkts_to_user(const struct sock *sk,
struct tcp_ao_info *ao_info,
sockopt_t *opt)
{
struct tcp_ao_getsockopt opt_in;
int user_len = opt->optlen;
struct kvec kvec;
/* First, initialize a small iter to read the first element */
sockopt_init_iter(opt, user_len, &kvec);
if (copy_from_iter(&opt_in, user_len, &opt->iter_in) != user_len)
return -EFAULT;
/* Now we know the actual buffer size */
sockopt_init_iter(opt, user_len * opt_in.nkeys, &kvec);
/* ... write the full array via copy_to_iter() ... */
}
4) Maintain two separate callbacks: ->getsockopt_iter (to be renamed to ->getsockopt
after the transition) and ->getsockopt_unsafe for legacy cases.
Regardless of which approach we take for these legacy implementations, I don't
believe any of them invalidate the current patchset from a design standpoint.
Since these legacy protocols represent less than 1% of the cases, I'd prefer to
optimize for the common path and handle the exceptional cases as exceptions.
^ permalink raw reply
* Re: [PATCH net v4 0/2] stmmac crash/stall fixes when under memory pressure
From: Russell King (Oracle) @ 2026-04-10 12:23 UTC (permalink / raw)
To: Sam Edwards
Cc: Andrew Lunn, David S. Miller, Eric Dumazet, Jakub Kicinski,
Paolo Abeni, Maxime Coquelin, Alexandre Torgue, Maxime Chevallier,
Ovidiu Panait, Vladimir Oltean, Baruch Siach, Serge Semin,
Giuseppe Cavallaro, netdev, linux-stm32, linux-arm-kernel,
linux-kernel
In-Reply-To: <CAH5Ym4g3pbU_bWzMwJMdhEFv4K2sp3pty3g04=0=9Z80_LzW1w@mail.gmail.com>
On Thu, Apr 02, 2026 at 10:39:32AM -0700, Sam Edwards wrote:
> On Thu, Apr 2, 2026 at 10:16 AM Russell King (Oracle)
> <linux@armlinux.org.uk> wrote:
> > I've tested this on my Jetson Xavier platform. One of the issues I've
> > had is that running iperf3 results in the receive side stalling because
> > it runs out of descriptors. However, despite the receive ring
> > eventually being re-filled and the hardware appropriately prodded, it
> > steadfastly refuses to restart, despite the descriptors having been
> > updated.
>
> Hi Russell,
>
> Just to make sure I understand correctly: before my patches, you've
> been observing this problem on Xavier for a while (no interrupts, ring
> goes dry); with my patches, the ring is refilled, but the dwmac5
> doesn't resume DMA. (Ah, just saw your follow-up email.)
>
> > Any ideas?
>
> Off the top of my head, my hypothesis is that dwmac5 has an additional
> tripwire when the receive DMA is exhausted, and the
> stmmac_set_rx_tail_ptr()/stmmac_enable_dma_reception() at the end of
> stmmac_rx_refill() aren't sufficient to wake it back up.
>
> I think this is new to dwmac5, because my RK3588 (dwmac4.20 iirc)
> happily resumes after the same condition.
>
> You gave a lot of info; thanks! I'll try to scrape up some
> documentation on dwmac5 to see if there's something more
> stmmac_rx_refill() ought to be doing. I think I have a Xavier NX
> around here somewhere, I'll see if I can repro the problem.
I've added dma_rmb() into dwmac4_wrback_get_tx_status() and
dwmac4_wrback_get_rx_status(), and with that I've had an iperf3
instance finally complete... but only once:
root@tegra-ubuntu:~# iperf3 -c 192.168.248.1 -R
Connecting to host 192.168.248.1, port 5201
Reverse mode, remote host 192.168.248.1 is sending
[ 5] local 192.168.248.174 port 42232 connected to 192.168.248.1 port 5201
[ ID] Interval Transfer Bitrate
[ 5] 0.00-1.00 sec 50.8 MBytes 426 Mbits/sec
[ 5] 1.00-2.00 sec 54.9 MBytes 460 Mbits/sec
[ 5] 2.00-3.00 sec 54.0 MBytes 453 Mbits/sec
[ 5] 3.00-4.00 sec 53.8 MBytes 452 Mbits/sec
[ 5] 4.00-5.00 sec 52.4 MBytes 438 Mbits/sec
[ 5] 5.00-6.00 sec 54.3 MBytes 455 Mbits/sec
[ 5] 6.00-7.00 sec 53.7 MBytes 452 Mbits/sec
[ 5] 7.00-8.00 sec 52.8 MBytes 443 Mbits/sec
[ 5] 8.00-9.00 sec 53.7 MBytes 451 Mbits/sec
[ 5] 9.00-10.00 sec 54.3 MBytes 455 Mbits/sec
- - - - - - - - - - - - - - - - - - - - - - - - -
[ ID] Interval Transfer Bitrate Retr
[ 5] 0.00-10.01 sec 537 MBytes 450 Mbits/sec 13 sender
[ 5] 0.00-10.00 sec 535 MBytes 448 Mbits/sec receiver
iperf Done.
So, it seems better, but not completely solved.
diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
index 2994df41ec2c..119f31c94b61 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_descs.c
@@ -17,10 +17,12 @@ static int dwmac4_wrback_get_tx_status(struct stmmac_extra_stats *x,
struct dma_desc *p,
void __iomem *ioaddr)
{
- u32 tdes3 = le32_to_cpu(p->des3);
+ u32 tdes3;
int ret = tx_done;
/* Get tx owner first */
+ dma_rmb();
+ tdes3 = le32_to_cpu(p->des3);
if (unlikely(tdes3 & TDES3_OWN))
return tx_dma_own;
@@ -70,12 +72,12 @@ static int dwmac4_wrback_get_tx_status(struct stmmac_extra_stats *x,
static int dwmac4_wrback_get_rx_status(struct stmmac_extra_stats *x,
struct dma_desc *p)
{
- u32 rdes1 = le32_to_cpu(p->des1);
- u32 rdes2 = le32_to_cpu(p->des2);
- u32 rdes3 = le32_to_cpu(p->des3);
+ u32 rdes1, rdes2, rdes3;
int message_type;
int ret = good_frame;
+ dma_rmb();
+ rdes3 = le32_to_cpu(p->des3);
if (unlikely(rdes3 & RDES3_OWN))
return dma_own;
@@ -107,6 +109,7 @@ static int dwmac4_wrback_get_rx_status(struct stmmac_extra_stats *x,
message_type = FIELD_GET(RDES1_PTP_MSG_TYPE_MASK, rdes1);
+ rdes1 = le32_to_cpu(p->des1);
if (rdes1 & RDES1_IP_HDR_ERROR) {
x->ip_hdr_err++;
ret |= csum_none;
@@ -152,6 +155,7 @@ static int dwmac4_wrback_get_rx_status(struct stmmac_extra_stats *x,
if (rdes1 & RDES1_TIMESTAMP_DROPPED)
x->timestamp_dropped++;
+ rdes2 = le32_to_cpu(p->des2);
if (unlikely(rdes2 & RDES2_SA_FILTER_FAIL)) {
x->sa_rx_filter_fail++;
ret = discard_frame;
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!
^ permalink raw reply related
* [patch 38/38] treewide: Remove asm/timex.h includes from generic code
From: Thomas Gleixner @ 2026-04-10 12:21 UTC (permalink / raw)
To: LKML
Cc: Arnd Bergmann, x86, Lu Baolu, iommu, Michael Grzeschik, netdev,
linux-wireless, Herbert Xu, linux-crypto, Vlastimil Babka,
linux-mm, David Woodhouse, Bernie Thompson, linux-fbdev,
Theodore Tso, linux-ext4, Andrew Morton, Uladzislau Rezki,
Marco Elver, Dmitry Vyukov, kasan-dev, Andrey Ryabinin,
Thomas Sailer, linux-hams, Jason A. Donenfeld, Richard Henderson,
linux-alpha, Russell King, linux-arm-kernel, Catalin Marinas,
Huacai Chen, loongarch, Geert Uytterhoeven, linux-m68k,
Dinh Nguyen, Jonas Bonn, linux-openrisc, Helge Deller,
linux-parisc, Michael Ellerman, linuxppc-dev, Paul Walmsley,
linux-riscv, Heiko Carstens, linux-s390, David S. Miller,
sparclinux
In-Reply-To: <20260410120044.031381086@kernel.org>
asm/timex.h does not provide any functionality for non-architecture code
anymore.
Remove the asm-generic fallback and all references in include and source
files along with the random_get_entropy() #ifdeffery in timex.h.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
---
include/asm-generic/Kbuild | 1 -
include/asm-generic/timex.h | 15 ---------------
include/linux/random.h | 3 +++
include/linux/timex.h | 26 --------------------------
kernel/time/timer.c | 1 -
lib/interval_tree_test.c | 1 -
lib/rbtree_test.c | 1 -
7 files changed, 3 insertions(+), 45 deletions(-)
--- a/include/asm-generic/Kbuild
+++ b/include/asm-generic/Kbuild
@@ -56,7 +56,6 @@ mandatory-y += shmparam.h
mandatory-y += simd.h
mandatory-y += softirq_stack.h
mandatory-y += switch_to.h
-mandatory-y += timex.h
mandatory-y += tlbflush.h
mandatory-y += topology.h
mandatory-y += trace_clock.h
--- a/include/asm-generic/timex.h
+++ /dev/null
@@ -1,15 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef __ASM_GENERIC_TIMEX_H
-#define __ASM_GENERIC_TIMEX_H
-
-/*
- * If you have a cycle counter, return the value here.
- */
-#ifndef get_cycles
-static inline cycles_t get_cycles(void)
-{
- return 0;
-}
-#endif
-
-#endif /* __ASM_GENERIC_TIMEX_H */
--- a/include/linux/random.h
+++ b/include/linux/random.h
@@ -1,3 +1,4 @@
+
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_RANDOM_H
@@ -152,6 +153,8 @@ unsigned long random_get_entropy_fallbac
*/
#ifdef CONFIG_ARCH_HAS_RANDOM_ENTROPY
#include <asm/random.h>
+#else
+#define random_get_entropy() random_get_entropy_fallback()
#endif
#endif /* _LINUX_RANDOM_H */
--- a/include/linux/timex.h
+++ b/include/linux/timex.h
@@ -62,32 +62,6 @@
#include <linux/types.h>
#include <linux/param.h>
-unsigned long random_get_entropy_fallback(void);
-
-#include <asm/timex.h>
-
-#ifndef CONFIG_ARCH_HAS_RANDOM_ENTROPY
-#ifndef random_get_entropy
-/*
- * The random_get_entropy() function is used by the /dev/random driver
- * in order to extract entropy via the relative unpredictability of
- * when an interrupt takes places versus a high speed, fine-grained
- * timing source or cycle counter. Since it will be occurred on every
- * single interrupt, it must have a very low cost/overhead.
- *
- * By default we use get_cycles() for this purpose, but individual
- * architectures may override this in their asm/timex.h header file.
- * If a given arch does not have get_cycles(), then we fallback to
- * using random_get_entropy_fallback().
- */
-#ifdef get_cycles
-#define random_get_entropy() ((unsigned long)get_cycles())
-#else
-#define random_get_entropy() random_get_entropy_fallback()
-#endif
-#endif
-#endif
-
/*
* SHIFT_PLL is used as a dampening factor to define how much we
* adjust the frequency correction for a given offset in PLL mode.
--- a/kernel/time/timer.c
+++ b/kernel/time/timer.c
@@ -48,7 +48,6 @@
#include <linux/uaccess.h>
#include <asm/unistd.h>
#include <asm/div64.h>
-#include <asm/timex.h>
#include <asm/io.h>
#include "tick-internal.h"
--- a/lib/interval_tree_test.c
+++ b/lib/interval_tree_test.c
@@ -4,7 +4,6 @@
#include <linux/interval_tree.h>
#include <linux/prandom.h>
#include <linux/slab.h>
-#include <asm/timex.h>
#include <linux/bitmap.h>
#include <linux/maple_tree.h>
--- a/lib/rbtree_test.c
+++ b/lib/rbtree_test.c
@@ -4,7 +4,6 @@
#include <linux/rbtree_augmented.h>
#include <linux/prandom.h>
#include <linux/slab.h>
-#include <asm/timex.h>
#define __param(type, name, init, msg) \
static type name = init; \
^ permalink raw reply
* [patch 37/38] x86: Select ARCH_HAS_RANDOM_ENTROPY
From: Thomas Gleixner @ 2026-04-10 12:21 UTC (permalink / raw)
To: LKML
Cc: x86, Arnd Bergmann, Lu Baolu, iommu, Michael Grzeschik, netdev,
linux-wireless, Herbert Xu, linux-crypto, Vlastimil Babka,
linux-mm, David Woodhouse, Bernie Thompson, linux-fbdev,
Theodore Tso, linux-ext4, Andrew Morton, Uladzislau Rezki,
Marco Elver, Dmitry Vyukov, kasan-dev, Andrey Ryabinin,
Thomas Sailer, linux-hams, Jason A. Donenfeld, Richard Henderson,
linux-alpha, Russell King, linux-arm-kernel, Catalin Marinas,
Huacai Chen, loongarch, Geert Uytterhoeven, linux-m68k,
Dinh Nguyen, Jonas Bonn, linux-openrisc, Helge Deller,
linux-parisc, Michael Ellerman, linuxppc-dev, Paul Walmsley,
linux-riscv, Heiko Carstens, linux-s390, David S. Miller,
sparclinux
In-Reply-To: <20260410120044.031381086@kernel.org>
The only remaining usage of get_cycles() is to provide random_get_entropy().
Switch x86 over to the new scheme of selecting ARCH_HAS_RANDOM_ENTROPY and
providing random_get_entropy() in asm/random.h.
Remove asm/timex.h as it has no functionality anymore.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: x86@kernel.org
---
arch/x86/Kconfig | 1 +
arch/x86/include/asm/random.h | 16 ++++++++++++++++
arch/x86/include/asm/timex.h | 17 -----------------
arch/x86/include/asm/tsc.h | 9 ---------
4 files changed, 17 insertions(+), 26 deletions(-)
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -101,6 +101,7 @@ config X86
select ARCH_HAS_PREEMPT_LAZY
select ARCH_HAS_PTDUMP
select ARCH_HAS_PTE_SPECIAL
+ select ARCH_HAS_RANDOM_ENTROPY
select ARCH_HAS_HW_PTE_YOUNG
select ARCH_HAS_NONLEAF_PMD_YOUNG if PGTABLE_LEVELS > 2
select ARCH_HAS_UACCESS_FLUSHCACHE if X86_64
--- /dev/null
+++ b/arch/x86/include/asm/random.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_RANDOM_H
+#define _ASM_X86_RANDOM_H
+
+#include <asm/processor.h>
+#include <asm/tsc.h>
+
+static inline unsigned long random_get_entropy(void)
+{
+ if (!IS_ENABLED(CONFIG_X86_TSC) &&
+ !cpu_feature_enabled(X86_FEATURE_TSC))
+ return random_get_entropy_fallback();
+ return rdtsc();
+}
+
+#endif /* _ASM_X86_RANDOM_H */
--- a/arch/x86/include/asm/timex.h
+++ /dev/null
@@ -1,17 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _ASM_X86_TIMEX_H
-#define _ASM_X86_TIMEX_H
-
-#include <asm/processor.h>
-#include <asm/tsc.h>
-
-static inline unsigned long random_get_entropy(void)
-{
- if (!IS_ENABLED(CONFIG_X86_TSC) &&
- !cpu_feature_enabled(X86_FEATURE_TSC))
- return random_get_entropy_fallback();
- return rdtsc();
-}
-#define random_get_entropy random_get_entropy
-
-#endif /* _ASM_X86_TIMEX_H */
--- a/arch/x86/include/asm/tsc.h
+++ b/arch/x86/include/asm/tsc.h
@@ -72,15 +72,6 @@ extern unsigned int tsc_khz;
extern void disable_TSC(void);
-static inline cycles_t get_cycles(void)
-{
- if (!IS_ENABLED(CONFIG_X86_TSC) &&
- !cpu_feature_enabled(X86_FEATURE_TSC))
- return 0;
- return rdtsc();
-}
-#define get_cycles get_cycles
-
extern void tsc_early_init(void);
extern void tsc_init(void);
extern void mark_tsc_unstable(char *reason);
^ permalink raw reply
* [patch 36/38] sparc: Select ARCH_HAS_RANDOM_ENTROPY for SPARC64
From: Thomas Gleixner @ 2026-04-10 12:21 UTC (permalink / raw)
To: LKML
Cc: David S. Miller, sparclinux, Arnd Bergmann, x86, Lu Baolu, iommu,
Michael Grzeschik, netdev, linux-wireless, Herbert Xu,
linux-crypto, Vlastimil Babka, linux-mm, David Woodhouse,
Bernie Thompson, linux-fbdev, Theodore Tso, linux-ext4,
Andrew Morton, Uladzislau Rezki, Marco Elver, Dmitry Vyukov,
kasan-dev, Andrey Ryabinin, Thomas Sailer, linux-hams,
Jason A. Donenfeld, Richard Henderson, linux-alpha, Russell King,
linux-arm-kernel, Catalin Marinas, Huacai Chen, loongarch,
Geert Uytterhoeven, linux-m68k, Dinh Nguyen, Jonas Bonn,
linux-openrisc, Helge Deller, linux-parisc, Michael Ellerman,
linuxppc-dev, Paul Walmsley, linux-riscv, Heiko Carstens,
linux-s390
In-Reply-To: <20260410120044.031381086@kernel.org>
The only remaining usage of get_cycles() is to provide random_get_entropy().
Switch sparc over to the new scheme of selecting ARCH_HAS_RANDOM_ENTROPY
and providing random_get_entropy() in asm/random.h.
Remove asm/timex*.h as it has no functionality anymore.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: sparclinux@vger.kernel.org
---
arch/sparc/Kconfig | 1 +
arch/sparc/include/asm/random.h | 15 +++++++++++++++
arch/sparc/include/asm/timex.h | 9 ---------
arch/sparc/include/asm/timex_64.h | 15 ---------------
arch/sparc/kernel/pcic.c | 1 -
arch/sparc/kernel/time_32.c | 1 -
arch/sparc/vdso/vclock_gettime.c | 1 -
7 files changed, 16 insertions(+), 27 deletions(-)
--- a/arch/sparc/Kconfig
+++ b/arch/sparc/Kconfig
@@ -71,6 +71,7 @@ config SPARC64
def_bool 64BIT
select ALTERNATE_USER_ADDRESS_SPACE
select ARCH_HAS_DELAY_TIMER
+ select ARCH_HAS_RANDOM_ENTROPY
select HAVE_FUNCTION_TRACER
select HAVE_FUNCTION_GRAPH_TRACER
select HAVE_KRETPROBES
--- /dev/null
+++ b/arch/sparc/include/asm/random.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _ASMsparc_RANDOM_H
+#define _ASMsparc_RANDOM_H
+
+#if defined(__sparc__) && defined(__arch64__)
+
+#include <asm/timer.h>
+
+static inline unsigned long random_get_entropy(void)
+{
+ return tick_ops->get_tick();
+}
+
+#endif
+#endif
--- a/arch/sparc/include/asm/timex.h
+++ /dev/null
@@ -1,9 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef ___ASM_SPARC_TIMEX_H
-#define ___ASM_SPARC_TIMEX_H
-#if defined(__sparc__) && defined(__arch64__)
-#include <asm/timex_64.h>
-#else
-#include <asm-generic/timex.h>
-#endif
-#endif
--- a/arch/sparc/include/asm/timex_64.h
+++ b/arch/sparc/include/asm/timex_64.h
@@ -1,15 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * linux/include/asm/timex.h
- *
- * sparc64 architecture timex specifications
- */
-#ifndef _ASMsparc64_TIMEX_H
-#define _ASMsparc64_TIMEX_H
-
-#include <asm/timer.h>
-
-/* Getting on the cycle counter on sparc64. */
-#define get_cycles() tick_ops->get_tick()
-
-#endif
--- a/arch/sparc/kernel/pcic.c
+++ b/arch/sparc/kernel/pcic.c
@@ -33,7 +33,6 @@
#include <asm/oplib.h>
#include <asm/prom.h>
#include <asm/pcic.h>
-#include <asm/timex.h>
#include <asm/timer.h>
#include <linux/uaccess.h>
#include <asm/irq_regs.h>
--- a/arch/sparc/kernel/time_32.c
+++ b/arch/sparc/kernel/time_32.c
@@ -37,7 +37,6 @@
#include <asm/mc146818rtc.h>
#include <asm/oplib.h>
-#include <asm/timex.h>
#include <asm/timer.h>
#include <asm/irq.h>
#include <asm/io.h>
--- a/arch/sparc/vdso/vclock_gettime.c
+++ b/arch/sparc/vdso/vclock_gettime.c
@@ -17,7 +17,6 @@
#include <linux/string.h>
#include <asm/io.h>
#include <asm/unistd.h>
-#include <asm/timex.h>
#include <asm/clocksource.h>
#include <asm/vvar.h>
^ permalink raw reply
* [patch 35/38] s390: Select ARCH_HAS_RANDOM_ENTROPY
From: Thomas Gleixner @ 2026-04-10 12:21 UTC (permalink / raw)
To: LKML
Cc: Heiko Carstens, linux-s390, Arnd Bergmann, x86, Lu Baolu, iommu,
Michael Grzeschik, netdev, linux-wireless, Herbert Xu,
linux-crypto, Vlastimil Babka, linux-mm, David Woodhouse,
Bernie Thompson, linux-fbdev, Theodore Tso, linux-ext4,
Andrew Morton, Uladzislau Rezki, Marco Elver, Dmitry Vyukov,
kasan-dev, Andrey Ryabinin, Thomas Sailer, linux-hams,
Jason A. Donenfeld, Richard Henderson, linux-alpha, Russell King,
linux-arm-kernel, Catalin Marinas, Huacai Chen, loongarch,
Geert Uytterhoeven, linux-m68k, Dinh Nguyen, Jonas Bonn,
linux-openrisc, Helge Deller, linux-parisc, Michael Ellerman,
linuxppc-dev, Paul Walmsley, linux-riscv, David S. Miller,
sparclinux
In-Reply-To: <20260410120044.031381086@kernel.org>
The only remaining non-architecture usage of get_cycles() is to provide
random_get_entropy().
Switch s390 over to the new scheme of selecting ARCH_HAS_RANDOM_ENTROPY and
providing random_get_entropy() in asm/random.h.
Add 'asm/timex.h' includes to the relevant files, so the global include can
be removed once all architectures are converted over.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: linux-s390@vger.kernel.org
---
arch/s390/Kconfig | 1 +
arch/s390/include/asm/random.h | 12 ++++++++++++
arch/s390/include/asm/timex.h | 6 ------
arch/s390/kernel/time.c | 1 +
arch/s390/kernel/vtime.c | 1 +
5 files changed, 15 insertions(+), 6 deletions(-)
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -108,6 +108,7 @@ config S390
select ARCH_HAS_PREEMPT_LAZY
select ARCH_HAS_PTDUMP
select ARCH_HAS_PTE_SPECIAL
+ select ARCH_HAS_RANDOM_ENTROPY
select ARCH_HAS_SCALED_CPUTIME
select ARCH_HAS_SET_DIRECT_MAP
select ARCH_HAS_SET_MEMORY
--- /dev/null
+++ b/arch/s390/include/asm/random.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_S390_RANDOM_H
+#define _ASM_S390_RANDOM_H
+
+#include <asm/timex.h>
+
+static inline unsigned long random_get_entropy(void)
+{
+ return (unsigned long)get_tod_clock_monotonic() >> 2;
+}
+
+#endif
--- a/arch/s390/include/asm/timex.h
+++ b/arch/s390/include/asm/timex.h
@@ -219,12 +219,6 @@ static inline unsigned long get_tod_cloc
return tod;
}
-static inline cycles_t get_cycles(void)
-{
- return (cycles_t)get_tod_clock_monotonic() >> 2;
-}
-#define get_cycles get_cycles
-
/**
* tod_to_ns - convert a TOD format value to nanoseconds
* @todval: to be converted TOD format value
--- a/arch/s390/kernel/time.c
+++ b/arch/s390/kernel/time.c
@@ -50,6 +50,7 @@
#include <asm/irq_regs.h>
#include <asm/vtimer.h>
#include <asm/stp.h>
+#include <asm/timex.h>
#include <asm/cio.h>
#include "entry.h"
--- a/arch/s390/kernel/vtime.c
+++ b/arch/s390/kernel/vtime.c
@@ -14,6 +14,7 @@
#include <linux/time.h>
#include <asm/alternative.h>
#include <asm/cputime.h>
+#include <asm/timex.h>
#include <asm/vtimer.h>
#include <asm/vtime.h>
#include <asm/cpu_mf.h>
^ permalink raw reply
* [patch 34/38] riscv: Select ARCH_HAS_RANDOM_ENTROPY
From: Thomas Gleixner @ 2026-04-10 12:21 UTC (permalink / raw)
To: LKML
Cc: Paul Walmsley, linux-riscv, Arnd Bergmann, x86, Lu Baolu, iommu,
Michael Grzeschik, netdev, linux-wireless, Herbert Xu,
linux-crypto, Vlastimil Babka, linux-mm, David Woodhouse,
Bernie Thompson, linux-fbdev, Theodore Tso, linux-ext4,
Andrew Morton, Uladzislau Rezki, Marco Elver, Dmitry Vyukov,
kasan-dev, Andrey Ryabinin, Thomas Sailer, linux-hams,
Jason A. Donenfeld, Richard Henderson, linux-alpha, Russell King,
linux-arm-kernel, Catalin Marinas, Huacai Chen, loongarch,
Geert Uytterhoeven, linux-m68k, Dinh Nguyen, Jonas Bonn,
linux-openrisc, Helge Deller, linux-parisc, Michael Ellerman,
linuxppc-dev, Heiko Carstens, linux-s390, David S. Miller,
sparclinux
In-Reply-To: <20260410120044.031381086@kernel.org>
The only remaining non-architecture usage of get_cycles() is to provide
random_get_entropy().
Switch riscv over to the new scheme of selecting ARCH_HAS_RANDOM_ENTROPY
and providing random_get_entropy() in asm/random.h.
Add 'asm/timex.h' includes to the relevant files, so the global include can
be removed once all architectures are converted over.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: Paul Walmsley <pjw@kernel.org>
Cc: linux-riscv@lists.infradead.org
---
arch/riscv/Kconfig | 1 +
arch/riscv/include/asm/random.h | 25 +++++++++++++++++++++++++
arch/riscv/include/asm/timex.h | 13 -------------
arch/riscv/kernel/unaligned_access_speed.c | 1 +
arch/riscv/kvm/vcpu_timer.c | 1 +
arch/riscv/lib/delay.c | 1 +
6 files changed, 29 insertions(+), 13 deletions(-)
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -47,6 +47,7 @@ config RISCV
select ARCH_HAS_PREPARE_SYNC_CORE_CMD
select ARCH_HAS_PTDUMP if MMU
select ARCH_HAS_PTE_SPECIAL
+ select ARCH_HAS_RANDOM_ENTROPY
select ARCH_HAS_SET_DIRECT_MAP if MMU
select ARCH_HAS_SET_MEMORY if MMU
select ARCH_HAS_STRICT_KERNEL_RWX if MMU && !XIP_KERNEL
--- /dev/null
+++ b/arch/riscv/include/asm/random.h
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _ASM_RISCV_RANDOM_H
+#define _ASM_RISCV_RANDOM_H
+
+#include <asm/timex.h>
+
+#ifdef CONFIG_RISCV_M_MODE
+/*
+ * Much like MIPS, we may not have a viable counter to use at an early point
+ * in the boot process. Unfortunately we don't have a fallback, so instead
+ * invoke the fallback function.
+ */
+static inline unsigned long random_get_entropy(void)
+{
+ if (unlikely(clint_time_val == NULL))
+ return random_get_entropy_fallback();
+ return get_cycles();
+}
+#else /* !CONFIG_RISCV_M_MODE */
+static inline unsigned long random_get_entropy(void)
+{
+ return get_cycles();
+}
+#endif /* CONFIG_RISCV_M_MODE */
+#endif /* _ASM_RISCV_RANDOM_H */
--- a/arch/riscv/include/asm/timex.h
+++ b/arch/riscv/include/asm/timex.h
@@ -31,19 +31,6 @@ static inline u32 get_cycles_hi(void)
#define get_cycles_hi get_cycles_hi
#endif /* CONFIG_64BIT */
-/*
- * Much like MIPS, we may not have a viable counter to use at an early point
- * in the boot process. Unfortunately we don't have a fallback, so instead
- * we just return 0.
- */
-static inline unsigned long random_get_entropy(void)
-{
- if (unlikely(clint_time_val == NULL))
- return random_get_entropy_fallback();
- return get_cycles();
-}
-#define random_get_entropy() random_get_entropy()
-
#else /* CONFIG_RISCV_M_MODE */
static inline cycles_t get_cycles(void)
--- a/arch/riscv/kernel/unaligned_access_speed.c
+++ b/arch/riscv/kernel/unaligned_access_speed.c
@@ -12,6 +12,7 @@
#include <linux/types.h>
#include <asm/cpufeature.h>
#include <asm/hwprobe.h>
+#include <asm/timex.h>
#include <asm/vector.h>
#include "copy-unaligned.h"
--- a/arch/riscv/kvm/vcpu_timer.c
+++ b/arch/riscv/kvm/vcpu_timer.c
@@ -14,6 +14,7 @@
#include <asm/delay.h>
#include <asm/kvm_nacl.h>
#include <asm/kvm_vcpu_timer.h>
+#include <asm/timex.h>
static u64 kvm_riscv_current_cycles(struct kvm_guest_timer *gt)
{
--- a/arch/riscv/lib/delay.c
+++ b/arch/riscv/lib/delay.c
@@ -10,6 +10,7 @@
#include <linux/export.h>
#include <asm/processor.h>
+#include <asm/timex.h>
/*
* This is copies from arch/arm/include/asm/delay.h
^ permalink raw reply
* [patch 33/38] powerpc: Select ARCH_HAS_RANDOM_ENTROPY
From: Thomas Gleixner @ 2026-04-10 12:21 UTC (permalink / raw)
To: LKML
Cc: Michael Ellerman, linuxppc-dev, Arnd Bergmann, x86, Lu Baolu,
iommu, Michael Grzeschik, netdev, linux-wireless, Herbert Xu,
linux-crypto, Vlastimil Babka, linux-mm, David Woodhouse,
Bernie Thompson, linux-fbdev, Theodore Tso, linux-ext4,
Andrew Morton, Uladzislau Rezki, Marco Elver, Dmitry Vyukov,
kasan-dev, Andrey Ryabinin, Thomas Sailer, linux-hams,
Jason A. Donenfeld, Richard Henderson, linux-alpha, Russell King,
linux-arm-kernel, Catalin Marinas, Huacai Chen, loongarch,
Geert Uytterhoeven, linux-m68k, Dinh Nguyen, Jonas Bonn,
linux-openrisc, Helge Deller, linux-parisc, Paul Walmsley,
linux-riscv, Heiko Carstens, linux-s390, David S. Miller,
sparclinux
In-Reply-To: <20260410120044.031381086@kernel.org>
The only remaining usage of get_cycles() is to provide random_get_entropy().
Switch powerpc over to the new scheme of selecting ARCH_HAS_RANDOM_ENTROPY
and providing random_get_entropy() in asm/random.h.
Remove asm/timex.h as it has no functionality anymore.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
---
arch/powerpc/Kconfig | 1 +
arch/powerpc/include/asm/random.h | 13 +++++++++++++
arch/powerpc/include/asm/timex.h | 21 ---------------------
3 files changed, 14 insertions(+), 21 deletions(-)
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -150,6 +150,7 @@ config PPC
select ARCH_HAS_PREEMPT_LAZY
select ARCH_HAS_PTDUMP
select ARCH_HAS_PTE_SPECIAL
+ select ARCH_HAS_RANDOM_ENTROPY
select ARCH_HAS_SCALED_CPUTIME if VIRT_CPU_ACCOUNTING_NATIVE && PPC_BOOK3S_64
select ARCH_HAS_SET_MEMORY
select ARCH_HAS_STRICT_KERNEL_RWX if (PPC_BOOK3S || PPC_8xx) && !HIBERNATION
--- /dev/null
+++ b/arch/powerpc/include/asm/random.h
@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_POWERPC_RANDOM_H
+#define _ASM_POWERPC_RANDOM_H
+
+#include <asm/cputable.h>
+#include <asm/vdso/timebase.h>
+
+static inline unsigned long random_get_entropy(void)
+{
+ return mftb();
+}
+
+#endif /* _ASM_POWERPC_RANDOM_H */
--- a/arch/powerpc/include/asm/timex.h
+++ b/arch/powerpc/include/asm/timex.h
@@ -1,21 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef _ASM_POWERPC_TIMEX_H
-#define _ASM_POWERPC_TIMEX_H
-
-#ifdef __KERNEL__
-
-/*
- * PowerPC architecture timex specifications
- */
-
-#include <asm/cputable.h>
-#include <asm/vdso/timebase.h>
-
-ostatic inline cycles_t get_cycles(void)
-{
- return mftb();
-}
-#define get_cycles get_cycles
-
-#endif /* __KERNEL__ */
-#endif /* _ASM_POWERPC_TIMEX_H */
^ permalink raw reply
* [patch 32/38] powerpc/spufs: Use mftb() directly
From: Thomas Gleixner @ 2026-04-10 12:21 UTC (permalink / raw)
To: LKML
Cc: Michael Ellerman, linuxppc-dev, Arnd Bergmann, x86, Lu Baolu,
iommu, Michael Grzeschik, netdev, linux-wireless, Herbert Xu,
linux-crypto, Vlastimil Babka, linux-mm, David Woodhouse,
Bernie Thompson, linux-fbdev, Theodore Tso, linux-ext4,
Andrew Morton, Uladzislau Rezki, Marco Elver, Dmitry Vyukov,
kasan-dev, Andrey Ryabinin, Thomas Sailer, linux-hams,
Jason A. Donenfeld, Richard Henderson, linux-alpha, Russell King,
linux-arm-kernel, Catalin Marinas, Huacai Chen, loongarch,
Geert Uytterhoeven, linux-m68k, Dinh Nguyen, Jonas Bonn,
linux-openrisc, Helge Deller, linux-parisc, Paul Walmsley,
linux-riscv, Heiko Carstens, linux-s390, David S. Miller,
sparclinux
In-Reply-To: <20260410120044.031381086@kernel.org>
There is no reason to indirect via get_cycles(), which is about to be
removed.
Use mftb() directly.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: linuxppc-dev@lists.ozlabs.org
---
arch/powerpc/platforms/cell/spufs/switch.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
--- a/arch/powerpc/platforms/cell/spufs/switch.c
+++ b/arch/powerpc/platforms/cell/spufs/switch.c
@@ -34,6 +34,7 @@
#include <asm/spu_priv1.h>
#include <asm/spu_csa.h>
#include <asm/mmu_context.h>
+#include <asm/time.h>
#include "spufs.h"
@@ -279,7 +280,7 @@ static inline void save_timebase(struct
* Read PPE Timebase High and Timebase low registers
* and save in CSA. TBD.
*/
- csa->suspend_time = get_cycles();
+ csa->suspend_time = mftb();
}
static inline void remove_other_spu_access(struct spu_state *csa,
@@ -1261,7 +1262,7 @@ static inline void setup_decr(struct spu
* in LSCSA.
*/
if (csa->priv2.mfc_control_RW & MFC_CNTL_DECREMENTER_RUNNING) {
- cycles_t resume_time = get_cycles();
+ cycles_t resume_time = mftb();
cycles_t delta_time = resume_time - csa->suspend_time;
csa->lscsa->decr_status.slot[0] = SPU_DECR_STATUS_RUNNING;
^ permalink raw reply
* [patch 31/38] parisc: Select ARCH_HAS_RANDOM_ENTROPY
From: Thomas Gleixner @ 2026-04-10 12:21 UTC (permalink / raw)
To: LKML
Cc: Helge Deller, linux-parisc, Arnd Bergmann, x86, Lu Baolu, iommu,
Michael Grzeschik, netdev, linux-wireless, Herbert Xu,
linux-crypto, Vlastimil Babka, linux-mm, David Woodhouse,
Bernie Thompson, linux-fbdev, Theodore Tso, linux-ext4,
Andrew Morton, Uladzislau Rezki, Marco Elver, Dmitry Vyukov,
kasan-dev, Andrey Ryabinin, Thomas Sailer, linux-hams,
Jason A. Donenfeld, Richard Henderson, linux-alpha, Russell King,
linux-arm-kernel, Catalin Marinas, Huacai Chen, loongarch,
Geert Uytterhoeven, linux-m68k, Dinh Nguyen, Jonas Bonn,
linux-openrisc, Michael Ellerman, linuxppc-dev, Paul Walmsley,
linux-riscv, Heiko Carstens, linux-s390, David S. Miller,
sparclinux
In-Reply-To: <20260410120044.031381086@kernel.org>
The only remaining non-architecture usage of get_cycles() is to provide
random_get_entropy().
Switch parisc over to the new scheme of selecting ARCH_HAS_RANDOM_ENTROPY
and providing random_get_entropy() in asm/random.h.
Add 'asm/timex.h' includes to the relevant files, so the global include can
be removed once all architectures are converted over.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: Helge Deller <deller@gmx.de>
Cc: linux-parisc@vger.kernel.org
---
arch/parisc/Kconfig | 1 +
arch/parisc/include/asm/random.h | 12 ++++++++++++
arch/parisc/include/asm/timex.h | 6 ------
arch/parisc/kernel/processor.c | 1 +
arch/parisc/kernel/time.c | 1 +
5 files changed, 15 insertions(+), 6 deletions(-)
--- a/arch/parisc/Kconfig
+++ b/arch/parisc/Kconfig
@@ -16,6 +16,7 @@ config PARISC
select ARCH_HAS_STRICT_MODULE_RWX
select ARCH_HAS_UBSAN
select ARCH_HAS_PTE_SPECIAL
+ select ARCH_HAS_RANDOM_ENTROPY
select ARCH_NO_SG_CHAIN
select ARCH_SPLIT_ARG64 if !64BIT
select ARCH_SUPPORTS_HUGETLBFS if PA20
--- /dev/null
+++ b/arch/parisc/include/asm/random.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASMPARISC_RANDOM_H
+#define _ASMPARISC_RANDOM_H
+
+#include <asm/timex.h>
+
+static inline unsigned long random_get_entropy(void)
+{
+ return get_cycles();
+}
+
+#endif
--- a/arch/parisc/include/asm/timex.h
+++ b/arch/parisc/include/asm/timex.h
@@ -1,9 +1,4 @@
/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * linux/include/asm-parisc/timex.h
- *
- * PARISC architecture timex specifications
- */
#ifndef _ASMPARISC_TIMEX_H
#define _ASMPARISC_TIMEX_H
@@ -13,6 +8,5 @@ static inline cycles_t get_cycles(void)
{
return mfctl(16);
}
-#define get_cycles get_cycles
#endif
--- a/arch/parisc/kernel/processor.c
+++ b/arch/parisc/kernel/processor.c
@@ -30,6 +30,7 @@
#include <asm/pdcpat.h>
#include <asm/irq.h> /* for struct irq_region */
#include <asm/parisc-device.h>
+#include <asm/timex.h>
struct system_cpuinfo_parisc boot_cpu_data __ro_after_init;
EXPORT_SYMBOL(boot_cpu_data);
--- a/arch/parisc/kernel/time.c
+++ b/arch/parisc/kernel/time.c
@@ -17,6 +17,7 @@
#include <linux/platform_device.h>
#include <asm/processor.h>
#include <asm/pdcpat.h>
+#include <asm/timex.h>
static u64 cr16_clock_freq;
static unsigned long clocktick;
^ permalink raw reply
* [patch 30/38] openrisc: Select ARCH_HAS_RANDOM_ENTROPY
From: Thomas Gleixner @ 2026-04-10 12:20 UTC (permalink / raw)
To: LKML
Cc: Jonas Bonn, linux-openrisc, Arnd Bergmann, x86, Lu Baolu, iommu,
Michael Grzeschik, netdev, linux-wireless, Herbert Xu,
linux-crypto, Vlastimil Babka, linux-mm, David Woodhouse,
Bernie Thompson, linux-fbdev, Theodore Tso, linux-ext4,
Andrew Morton, Uladzislau Rezki, Marco Elver, Dmitry Vyukov,
kasan-dev, Andrey Ryabinin, Thomas Sailer, linux-hams,
Jason A. Donenfeld, Richard Henderson, linux-alpha, Russell King,
linux-arm-kernel, Catalin Marinas, Huacai Chen, loongarch,
Geert Uytterhoeven, linux-m68k, Dinh Nguyen, Helge Deller,
linux-parisc, Michael Ellerman, linuxppc-dev, Paul Walmsley,
linux-riscv, Heiko Carstens, linux-s390, David S. Miller,
sparclinux
In-Reply-To: <20260410120044.031381086@kernel.org>
The only remaining non-architecture usage of get_cycles() is to provide
random_get_entropy().
Switch openrisc over to the new scheme of selecting ARCH_HAS_RANDOM_ENTROPY
and providing random_get_entropy() in asm/random.h.
Add 'asm/timex.h' includes to the relevant files, so the global include can
be removed once all architectures are converted over.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: linux-openrisc@vger.kernel.org
---
arch/openrisc/Kconfig | 1 +
arch/openrisc/include/asm/random.h | 12 ++++++++++++
arch/openrisc/include/asm/timex.h | 5 -----
arch/openrisc/lib/delay.c | 1 +
4 files changed, 14 insertions(+), 5 deletions(-)
--- a/arch/openrisc/Kconfig
+++ b/arch/openrisc/Kconfig
@@ -10,6 +10,7 @@ config OPENRISC
select ARCH_HAS_DELAY_TIMER
select ARCH_HAS_DMA_SET_UNCACHED
select ARCH_HAS_DMA_CLEAR_UNCACHED
+ select ARCH_HAS_RANDOM_ENTROPY
select ARCH_HAS_SYNC_DMA_FOR_DEVICE
select GENERIC_BUILTIN_DTB
select COMMON_CLK
--- /dev/null
+++ b/arch/openrisc/include/asm/random.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef __ASM_OPENRISC_RANDOM_H
+#define __ASM_OPENRISC_RANDOM_H
+
+#include <asm/timex.h>
+
+static inline unsigned long random_get_entropy(void)
+{
+ return get_cycles();
+}
+
+#endif
--- a/arch/openrisc/include/asm/timex.h
+++ b/arch/openrisc/include/asm/timex.h
@@ -9,13 +9,9 @@
* OpenRISC implementation:
* Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
*/
-
#ifndef __ASM_OPENRISC_TIMEX_H
#define __ASM_OPENRISC_TIMEX_H
-#define get_cycles get_cycles
-
-#include <asm-generic/timex.h>
#include <asm/spr.h>
#include <asm/spr_defs.h>
@@ -23,6 +19,5 @@ static inline cycles_t get_cycles(void)
{
return mfspr(SPR_TTCR);
}
-#define get_cycles get_cycles
#endif
--- a/arch/openrisc/lib/delay.c
+++ b/arch/openrisc/lib/delay.c
@@ -18,6 +18,7 @@
#include <linux/init.h>
#include <asm/param.h>
+#include <asm/timex.h>
#include <asm/processor.h>
bool delay_read_timer(unsigned long *timer_value)
^ permalink raw reply
* [patch 29/38] nios2: Select ARCH_HAS_RANDOM_ENTROPY
From: Thomas Gleixner @ 2026-04-10 12:20 UTC (permalink / raw)
To: LKML
Cc: Dinh Nguyen, Arnd Bergmann, x86, Lu Baolu, iommu,
Michael Grzeschik, netdev, linux-wireless, Herbert Xu,
linux-crypto, Vlastimil Babka, linux-mm, David Woodhouse,
Bernie Thompson, linux-fbdev, Theodore Tso, linux-ext4,
Andrew Morton, Uladzislau Rezki, Marco Elver, Dmitry Vyukov,
kasan-dev, Andrey Ryabinin, Thomas Sailer, linux-hams,
Jason A. Donenfeld, Richard Henderson, linux-alpha, Russell King,
linux-arm-kernel, Catalin Marinas, Huacai Chen, loongarch,
Geert Uytterhoeven, linux-m68k, Jonas Bonn, linux-openrisc,
Helge Deller, linux-parisc, Michael Ellerman, linuxppc-dev,
Paul Walmsley, linux-riscv, Heiko Carstens, linux-s390,
David S. Miller, sparclinux
In-Reply-To: <20260410120044.031381086@kernel.org>
The only remaining non-architecture usage of get_cycles() is to provide
random_get_entropy().
Switch nios2 over to the new scheme of selecting ARCH_HAS_RANDOM_ENTROPY
and providing random_get_entropy() in asm/random.h.
Add 'asm/timex.h' includes to the relevant files, so the global include can
be removed once all architectures are converted over.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: Dinh Nguyen <dinguyen@kernel.org>
---
arch/nios2/Kconfig | 1 +
arch/nios2/include/asm/random.h | 14 ++++++++++++++
arch/nios2/include/asm/timex.h | 5 +----
arch/nios2/kernel/time.c | 4 ++--
4 files changed, 18 insertions(+), 6 deletions(-)
--- a/arch/nios2/Kconfig
+++ b/arch/nios2/Kconfig
@@ -7,6 +7,7 @@ config NIOS2
select ARCH_HAS_SYNC_DMA_FOR_CPU
select ARCH_HAS_SYNC_DMA_FOR_DEVICE
select ARCH_HAS_DMA_SET_UNCACHED
+ select ARCH_HAS_RANDOM_ENTROPY
select ARCH_NO_SWAP
select COMMON_CLK
select TIMER_OF
--- /dev/null
+++ b/arch/nios2/include/asm/random.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _ASM_NIOS2_RANDOM_H
+#define _ASM_NIOS2_RANDOM_H
+
+#include <asm/timex.h>
+
+static inline unsigned long random_get_entropy(void)
+{
+ unsigned long c = get_cycles();
+
+ return c ? c : random_get_entropy_fallback();
+}
+
+#endif
--- a/arch/nios2/include/asm/timex.h
+++ b/arch/nios2/include/asm/timex.h
@@ -5,9 +5,6 @@
#ifndef _ASM_NIOS2_TIMEX_H
#define _ASM_NIOS2_TIMEX_H
-extern cycles_t get_cycles(void);
-#define get_cycles get_cycles
-
-#define random_get_entropy() (((unsigned long)get_cycles()) ?: random_get_entropy_fallback())
+cycles_t get_cycles(void);
#endif
--- a/arch/nios2/kernel/time.c
+++ b/arch/nios2/kernel/time.c
@@ -7,7 +7,6 @@
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
-
#include <linux/export.h>
#include <linux/interrupt.h>
#include <linux/clockchips.h>
@@ -19,6 +18,8 @@
#include <linux/io.h>
#include <linux/slab.h>
+#include <asm/timex.h>
+
#define ALTR_TIMER_COMPATIBLE "altr,timer-1.0"
#define ALTERA_TIMER_STATUS_REG 0
@@ -112,7 +113,6 @@ cycles_t get_cycles(void)
return nios2_timer_read(&nios2_cs.cs);
return 0;
}
-EXPORT_SYMBOL(get_cycles);
static void nios2_timer_start(struct nios2_timer *timer)
{
^ permalink raw reply
* [patch 28/38] mips: Select ARCH_HAS_RANDOM_ENTROPY
From: Thomas Gleixner @ 2026-04-10 12:20 UTC (permalink / raw)
To: LKML
Cc: Arnd Bergmann, x86, Lu Baolu, iommu, Michael Grzeschik, netdev,
linux-wireless, Herbert Xu, linux-crypto, Vlastimil Babka,
linux-mm, David Woodhouse, Bernie Thompson, linux-fbdev,
Theodore Tso, linux-ext4, Andrew Morton, Uladzislau Rezki,
Marco Elver, Dmitry Vyukov, kasan-dev, Andrey Ryabinin,
Thomas Sailer, linux-hams, Jason A. Donenfeld, Richard Henderson,
linux-alpha, Russell King, linux-arm-kernel, Catalin Marinas,
Huacai Chen, loongarch, Geert Uytterhoeven, linux-m68k,
Dinh Nguyen, Jonas Bonn, linux-openrisc, Helge Deller,
linux-parisc, Michael Ellerman, linuxppc-dev, Paul Walmsley,
linux-riscv, Heiko Carstens, linux-s390, David S. Miller,
sparclinux
In-Reply-To: <20260410120044.031381086@kernel.org>
The only remaining usage of get_cycles() is to provide random_get_entropy().
Switch mips over to the new scheme of selecting ARCH_HAS_RANDOM_ENTROPY
and providing random_get_entropy() in asm/random.h.
As a consequence this unearthed a nasty include dependency hell because
arbitrary code relies on a magic include of asm/timex.h. Including the
headers in asm/random.h turned out to be impossible as well.
The only solution for now is to uninline random_get_entropy(). Fix up all
other dependencies on the content of asm/timex.h in those files which
really depend on it.
Remove asm/timex.h as it has no functionality anymore.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
---
arch/mips/Kconfig | 1
arch/mips/generic/init.c | 1
arch/mips/include/asm/random.h | 7 +++
arch/mips/include/asm/timex.h | 92 -----------------------------------------
arch/mips/kernel/pm-cps.c | 1
arch/mips/kernel/proc.c | 1
arch/mips/kernel/relocate.c | 1
arch/mips/kernel/time.c | 53 +++++++++++++++++++++++
arch/mips/lib/dump_tlb.c | 1
arch/mips/mm/cache.c | 1
10 files changed, 66 insertions(+), 93 deletions(-)
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -19,6 +19,7 @@ config MIPS
select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
select ARCH_HAS_UBSAN
select ARCH_HAS_GCOV_PROFILE_ALL
+ select ARCH_HAS_RANDOM_ENTROPY
select ARCH_KEEP_MEMBLOCK
select ARCH_USE_BUILTIN_BSWAP
select ARCH_USE_CMPXCHG_LOCKREF if 64BIT
--- a/arch/mips/generic/init.c
+++ b/arch/mips/generic/init.c
@@ -12,6 +12,7 @@
#include <linux/of_fdt.h>
#include <asm/bootinfo.h>
+#include <asm/cpu-type.h>
#include <asm/fw/fw.h>
#include <asm/irq_cpu.h>
#include <asm/machine.h>
--- /dev/null
+++ b/arch/mips/include/asm/random.h
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-v2.0-only */
+#ifndef _ASM_RANDOM_H
+#define _ASM_RANDOM_H
+
+unsigned long random_get_entropy(void);
+
+#endif /* _ASM_RANDOM_H */
--- a/arch/mips/include/asm/timex.h
+++ /dev/null
@@ -1,92 +0,0 @@
-/*
- * This file is subject to the terms and conditions of the GNU General Public
- * License. See the file "COPYING" in the main directory of this archive
- * for more details.
- *
- * Copyright (C) 1998, 1999, 2003 by Ralf Baechle
- * Copyright (C) 2014 by Maciej W. Rozycki
- */
-#ifndef _ASM_TIMEX_H
-#define _ASM_TIMEX_H
-
-#ifdef __KERNEL__
-
-#include <linux/compiler.h>
-
-#include <asm/cpu.h>
-#include <asm/cpu-features.h>
-#include <asm/mipsregs.h>
-#include <asm/cpu-type.h>
-
-/*
- * Standard way to access the cycle counter.
- * Currently only used on SMP for scheduling.
- *
- * Only the low 32 bits are available as a continuously counting entity.
- * But this only means we'll force a reschedule every 8 seconds or so,
- * which isn't an evil thing.
- *
- * We know that all SMP capable CPUs have cycle counters.
- */
-
-/*
- * On R4000/R4400 an erratum exists such that if the cycle counter is
- * read in the exact moment that it is matching the compare register,
- * no interrupt will be generated.
- *
- * There is a suggested workaround and also the erratum can't strike if
- * the compare interrupt isn't being used as the clock source device.
- * However for now the implementation of this function doesn't get these
- * fine details right.
- */
-static inline int can_use_mips_counter(unsigned int prid)
-{
- int comp = (prid & PRID_COMP_MASK) != PRID_COMP_LEGACY;
-
- if (__builtin_constant_p(cpu_has_counter) && !cpu_has_counter)
- return 0;
- else if (__builtin_constant_p(cpu_has_mips_r) && cpu_has_mips_r)
- return 1;
- else if (likely(!__builtin_constant_p(cpu_has_mips_r) && comp))
- return 1;
- /* Make sure we don't peek at cpu_data[0].options in the fast path! */
- if (!__builtin_constant_p(cpu_has_counter))
- asm volatile("" : "=m" (cpu_data[0].options));
- if (likely(cpu_has_counter &&
- prid > (PRID_IMP_R4000 | PRID_REV_ENCODE_44(15, 15))))
- return 1;
- else
- return 0;
-}
-
-static inline cycles_t get_cycles(void)
-{
- if (can_use_mips_counter(read_c0_prid()))
- return read_c0_count();
- else
- return 0; /* no usable counter */
-}
-#define get_cycles get_cycles
-
-/*
- * Like get_cycles - but where c0_count is not available we desperately
- * use c0_random in an attempt to get at least a little bit of entropy.
- */
-static inline unsigned long random_get_entropy(void)
-{
- unsigned int c0_random;
-
- if (can_use_mips_counter(read_c0_prid()))
- return read_c0_count();
-
- if (cpu_has_3kex)
- c0_random = (read_c0_random() >> 8) & 0x3f;
- else
- c0_random = read_c0_random() & 0x3f;
- return (random_get_entropy_fallback() << 6) | (0x3f - c0_random);
-}
-#define random_get_entropy random_get_entropy
-
-#endif /* __KERNEL__ */
-
-#endif /* _ASM_TIMEX_H */
--- a/arch/mips/kernel/pm-cps.c
+++ b/arch/mips/kernel/pm-cps.c
@@ -13,6 +13,7 @@
#include <asm/asm-offsets.h>
#include <asm/cacheflush.h>
#include <asm/cacheops.h>
+#include <asm/cpu-type.h>
#include <asm/idle.h>
#include <asm/mips-cps.h>
#include <asm/mipsmtregs.h>
--- a/arch/mips/kernel/proc.c
+++ b/arch/mips/kernel/proc.c
@@ -11,6 +11,7 @@
#include <asm/bootinfo.h>
#include <asm/cpu.h>
#include <asm/cpu-features.h>
+#include <asm/cpu-type.h>
#include <asm/idle.h>
#include <asm/mipsregs.h>
#include <asm/processor.h>
--- a/arch/mips/kernel/relocate.c
+++ b/arch/mips/kernel/relocate.c
@@ -13,7 +13,6 @@
#include <asm/fw/fw.h>
#include <asm/sections.h>
#include <asm/setup.h>
-#include <asm/timex.h>
#include <linux/elf.h>
#include <linux/kernel.h>
#include <linux/libfdt.h>
--- a/arch/mips/kernel/time.c
+++ b/arch/mips/kernel/time.c
@@ -2,6 +2,7 @@
/*
* Copyright 2001 MontaVista Software Inc.
* Author: Jun Sun, jsun@mvista.com or jsun@junsun.net
+ * Copyright (C) 1998, 1999, 2003 by Ralf Baechle
* Copyright (c) 2003, 2004 Maciej W. Rozycki
*
* Common time service routines for MIPS machines.
@@ -21,9 +22,12 @@
#include <linux/cpufreq.h>
#include <linux/delay.h>
+#include <asm/cpu.h>
#include <asm/cpu-features.h>
#include <asm/cpu-type.h>
#include <asm/div64.h>
+#include <asm/mipsregs.h>
+#include <asm/random.h>
#include <asm/time.h>
#ifdef CONFIG_CPU_FREQ
@@ -150,6 +154,55 @@ static __init int cpu_has_mfc0_count_bug
return 0;
}
+
+/*
+ * On R4000/R4400 an erratum exists such that if the cycle counter is
+ * read in the exact moment that it is matching the compare register,
+ * no interrupt will be generated.
+ *
+ * There is a suggested workaround and also the erratum can't strike if
+ * the compare interrupt isn't being used as the clock source device.
+ * However for now the implementation of this function doesn't get these
+ * fine details right.
+ */
+static inline int can_use_mips_counter(unsigned int prid)
+{
+ int comp = (prid & PRID_COMP_MASK) != PRID_COMP_LEGACY;
+
+ if (__builtin_constant_p(cpu_has_counter) && !cpu_has_counter)
+ return 0;
+ else if (__builtin_constant_p(cpu_has_mips_r) && cpu_has_mips_r)
+ return 1;
+ else if (likely(!__builtin_constant_p(cpu_has_mips_r) && comp))
+ return 1;
+ /* Make sure we don't peek at cpu_data[0].options in the fast path! */
+ if (!__builtin_constant_p(cpu_has_counter))
+ asm volatile("" : "=m" (cpu_data[0].options));
+ if (likely(cpu_has_counter &&
+ prid > (PRID_IMP_R4000 | PRID_REV_ENCODE_44(15, 15))))
+ return 1;
+ else
+ return 0;
+}
+
+/*
+ * Like get_cycles - but where c0_count is not available we desperately
+ * use c0_random in an attempt to get at least a little bit of entropy.
+ */
+unsigned long random_get_entropy(void)
+{
+ unsigned int c0_random;
+
+ if (can_use_mips_counter(read_c0_prid()))
+ return read_c0_count();
+
+ if (cpu_has_3kex)
+ c0_random = (read_c0_random() >> 8) & 0x3f;
+ else
+ c0_random = read_c0_random() & 0x3f;
+ return (random_get_entropy_fallback() << 6) | (0x3f - c0_random);
+}
+
void __init time_init(void)
{
plat_time_init();
--- a/arch/mips/lib/dump_tlb.c
+++ b/arch/mips/lib/dump_tlb.c
@@ -8,6 +8,7 @@
#include <linux/kernel.h>
#include <linux/mm.h>
+#include <asm/cpu-type.h>
#include <asm/hazards.h>
#include <asm/mipsregs.h>
#include <asm/mmu_context.h>
--- a/arch/mips/mm/cache.c
+++ b/arch/mips/mm/cache.c
@@ -22,6 +22,7 @@
#include <asm/processor.h>
#include <asm/cpu.h>
#include <asm/cpu-features.h>
+#include <asm/cpu-type.h>
#include <asm/setup.h>
#include <asm/pgtable.h>
^ permalink raw reply
* [patch 27/38] m68k: Select ARCH_HAS_RANDOM_ENTROPY
From: Thomas Gleixner @ 2026-04-10 12:20 UTC (permalink / raw)
To: LKML
Cc: Geert Uytterhoeven, linux-m68k, Arnd Bergmann, x86, Lu Baolu,
iommu, Michael Grzeschik, netdev, linux-wireless, Herbert Xu,
linux-crypto, Vlastimil Babka, linux-mm, David Woodhouse,
Bernie Thompson, linux-fbdev, Theodore Tso, linux-ext4,
Andrew Morton, Uladzislau Rezki, Marco Elver, Dmitry Vyukov,
kasan-dev, Andrey Ryabinin, Thomas Sailer, linux-hams,
Jason A. Donenfeld, Richard Henderson, linux-alpha, Russell King,
linux-arm-kernel, Catalin Marinas, Huacai Chen, loongarch,
Dinh Nguyen, Jonas Bonn, linux-openrisc, Helge Deller,
linux-parisc, Michael Ellerman, linuxppc-dev, Paul Walmsley,
linux-riscv, Heiko Carstens, linux-s390, David S. Miller,
sparclinux
In-Reply-To: <20260410120044.031381086@kernel.org>
The only remaining usage of get_cycles() is to provide
random_get_entropy().
Switch m68k over to the new scheme of selecting ARCH_HAS_RANDOM_ENTROPY and
providing random_get_entropy() in asm/random.h.
Remove asm/timex.h as it has no functionality anymore.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: linux-m68k@lists.linux-m68k.org
---
arch/m68k/Kconfig | 1 +
arch/m68k/amiga/config.c | 1 +
arch/m68k/include/asm/random.h | 14 ++++++++++++++
arch/m68k/include/asm/timex.h | 25 -------------------------
arch/m68k/kernel/time.c | 2 +-
5 files changed, 17 insertions(+), 26 deletions(-)
--- a/arch/m68k/Kconfig
+++ b/arch/m68k/Kconfig
@@ -8,6 +8,7 @@ config M68K
select ARCH_HAS_CPU_FINALIZE_INIT if MMU
select ARCH_HAS_CURRENT_STACK_POINTER
select ARCH_HAS_DMA_PREP_COHERENT if M68K_NONCOHERENT_DMA && !COLDFIRE
+ select ARCH_HAS_RANDOM_ENTROPY
select ARCH_HAS_SYNC_DMA_FOR_DEVICE if M68K_NONCOHERENT_DMA
select ARCH_HAVE_NMI_SAFE_CMPXCHG if RMW_INSNS
select ARCH_MIGHT_HAVE_PC_PARPORT if ISA
--- a/arch/m68k/amiga/config.c
+++ b/arch/m68k/amiga/config.c
@@ -36,6 +36,7 @@
#include <asm/machdep.h>
#include <asm/io.h>
#include <asm/config.h>
+#include <asm/random.h>
#include "amiga.h"
--- /dev/null
+++ b/arch/m68k/include/asm/random.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASMm68K_RANDOM_H
+#define _ASMm68K_RANDOM_H
+
+extern unsigned long (*mach_random_get_entropy)(void);
+
+static inline unsigned long random_get_entropy(void)
+{
+ if (mach_random_get_entropy)
+ return mach_random_get_entropy();
+ return random_get_entropy_fallback();
+}
+
+#endif
--- a/arch/m68k/include/asm/timex.h
+++ /dev/null
@@ -1,25 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * linux/include/asm-m68k/timex.h
- *
- * m68k architecture timex specifications
- */
-#ifndef _ASMm68K_TIMEX_H
-#define _ASMm68K_TIMEX_H
-
-static inline cycles_t get_cycles(void)
-{
- return 0;
-}
-
-extern unsigned long (*mach_random_get_entropy)(void);
-
-static inline unsigned long random_get_entropy(void)
-{
- if (mach_random_get_entropy)
- return mach_random_get_entropy();
- return random_get_entropy_fallback();
-}
-#define random_get_entropy random_get_entropy
-
-#endif
--- a/arch/m68k/kernel/time.c
+++ b/arch/m68k/kernel/time.c
@@ -26,12 +26,12 @@
#include <asm/machdep.h>
#include <asm/io.h>
#include <asm/irq_regs.h>
+#include <asm/random.h>
#include <linux/time.h>
#include <linux/timex.h>
#include <linux/profile.h>
-
unsigned long (*mach_random_get_entropy)(void);
EXPORT_SYMBOL_GPL(mach_random_get_entropy);
^ permalink raw reply
* [patch 26/38] loongarch: Select ARCH_HAS_RANDOM_ENTROPY
From: Thomas Gleixner @ 2026-04-10 12:20 UTC (permalink / raw)
To: LKML
Cc: Huacai Chen, loongarch, Arnd Bergmann, x86, Lu Baolu, iommu,
Michael Grzeschik, netdev, linux-wireless, Herbert Xu,
linux-crypto, Vlastimil Babka, linux-mm, David Woodhouse,
Bernie Thompson, linux-fbdev, Theodore Tso, linux-ext4,
Andrew Morton, Uladzislau Rezki, Marco Elver, Dmitry Vyukov,
kasan-dev, Andrey Ryabinin, Thomas Sailer, linux-hams,
Jason A. Donenfeld, Richard Henderson, linux-alpha, Russell King,
linux-arm-kernel, Catalin Marinas, Geert Uytterhoeven, linux-m68k,
Dinh Nguyen, Jonas Bonn, linux-openrisc, Helge Deller,
linux-parisc, Michael Ellerman, linuxppc-dev, Paul Walmsley,
linux-riscv, Heiko Carstens, linux-s390, David S. Miller,
sparclinux
In-Reply-To: <20260410120044.031381086@kernel.org>
The only remaining non-architecture usage of get_cycles() is to provide
random_get_entropy().
Switch loongarch over to the new scheme of selecting ARCH_HAS_RANDOM_ENTROPY
and providing random_get_entropy() in asm/random.h.
Add 'asm/timex.h' includes to the relevant files, so the global include can
be removed once all architectures are converted over.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: loongarch@lists.linux.dev
---
arch/loongarch/Kconfig | 1 +
arch/loongarch/include/asm/random.h | 15 +++++++++++++++
arch/loongarch/kernel/syscall.c | 1 +
arch/loongarch/lib/delay.c | 2 +-
4 files changed, 18 insertions(+), 1 deletion(-)
--- a/arch/loongarch/Kconfig
+++ b/arch/loongarch/Kconfig
@@ -26,6 +26,7 @@ config LOONGARCH
select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
select ARCH_HAS_PREEMPT_LAZY
select ARCH_HAS_PTE_SPECIAL
+ select ARCH_HAS_RANDOM_ENTROPY
select ARCH_HAS_SET_MEMORY
select ARCH_HAS_SET_DIRECT_MAP
select ARCH_HAS_TICK_BROADCAST if GENERIC_CLOCKEVENTS_BROADCAST
--- /dev/null
+++ b/arch/loongarch/include/asm/random.h
@@ -0,0 +1,15 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
+ */
+#ifndef _ASM_RANDOM_H
+#define _ASM_RANDOM_H
+
+#include <asm/timex.h>
+
+static inline unsigned long random_get_entropy(void)
+{
+ return get_cycles();
+}
+
+#endif /* _ASM_RANDOM_H */
--- a/arch/loongarch/kernel/syscall.c
+++ b/arch/loongarch/kernel/syscall.c
@@ -19,6 +19,7 @@
#include <asm/loongarch.h>
#include <asm/signal.h>
#include <asm/switch_to.h>
+#include <asm/timex.h>
#include <asm-generic/syscalls.h>
#undef __SYSCALL
--- a/arch/loongarch/lib/delay.c
+++ b/arch/loongarch/lib/delay.c
@@ -5,9 +5,9 @@
#include <linux/delay.h>
#include <linux/export.h>
#include <linux/smp.h>
-#include <linux/timex.h>
#include <asm/processor.h>
+#include <asm/timex.h>
void __delay(unsigned long cycles)
{
^ permalink raw reply
* [patch 25/38] arm64: Select ARCH_HAS_RANDOM_ENTROPY
From: Thomas Gleixner @ 2026-04-10 12:20 UTC (permalink / raw)
To: LKML
Cc: Catalin Marinas, linux-arm-kernel, Arnd Bergmann, x86, Lu Baolu,
iommu, Michael Grzeschik, netdev, linux-wireless, Herbert Xu,
linux-crypto, Vlastimil Babka, linux-mm, David Woodhouse,
Bernie Thompson, linux-fbdev, Theodore Tso, linux-ext4,
Andrew Morton, Uladzislau Rezki, Marco Elver, Dmitry Vyukov,
kasan-dev, Andrey Ryabinin, Thomas Sailer, linux-hams,
Jason A. Donenfeld, Richard Henderson, linux-alpha, Russell King,
Huacai Chen, loongarch, Geert Uytterhoeven, linux-m68k,
Dinh Nguyen, Jonas Bonn, linux-openrisc, Helge Deller,
linux-parisc, Michael Ellerman, linuxppc-dev, Paul Walmsley,
linux-riscv, Heiko Carstens, linux-s390, David S. Miller,
sparclinux
In-Reply-To: <20260410120044.031381086@kernel.org>
The only remaining usage of get_cycles() is to provide random_get_entropy().
Switch arm64 over to the new scheme of selecting ARCH_HAS_RANDOM_ENTROPY
and providing random_get_entropy() in asm/random.h.
As a consequence this unearthed a nasty include dependecy hell where random
code including rqspinlock.h relies on a magic include of asm/arch_timer.h.
Including the headers in asm/random.h turned out to be impossible as well.
The only solution for now is to uninline random_get_entropy(). Fix up all
other dependencies on the content of asm/timex.h in those files which
really depend on it.
Remove asm/timex.h as it has no functionality anymore.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
---
arch/arm64/Kconfig | 1 +
arch/arm64/include/asm/io.h | 5 +++--
arch/arm64/include/asm/random.h | 11 +++++++++++
arch/arm64/include/asm/rqspinlock.h | 1 +
arch/arm64/include/asm/timex.h | 18 ------------------
arch/arm64/kernel/time.c | 6 ++++++
arch/arm64/kernel/topology.c | 1 +
arch/arm64/kernel/traps.c | 1 +
arch/arm64/kvm/emulate-nested.c | 1 +
arch/arm64/kvm/hyp/include/hyp/switch.h | 1 +
arch/arm64/lib/delay.c | 1 +
drivers/irqchip/irq-apple-aic.c | 1 +
12 files changed, 28 insertions(+), 20 deletions(-)
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -45,6 +45,7 @@ config ARM64
select ARCH_HAS_PREEMPT_LAZY
select ARCH_HAS_PTDUMP
select ARCH_HAS_PTE_SPECIAL
+ select ARCH_HAS_RANDOM_ENTROPY
select ARCH_HAS_HW_PTE_YOUNG
select ARCH_HAS_SETUP_DMA_OPS
select ARCH_HAS_SET_DIRECT_MAP
--- a/arch/arm64/include/asm/io.h
+++ b/arch/arm64/include/asm/io.h
@@ -100,12 +100,13 @@ static __always_inline u64 __raw_readq(c
({ \
unsigned long tmp; \
\
- dma_rmb(); \
+ dma_rmb(); \
\
/* \
* Create a dummy control dependency from the IO read to any \
* later instructions. This ensures that a subsequent call to \
- * udelay() will be ordered due to the ISB in get_cycles(). \
+ * udelay() will be ordered due to the ISB in \
+ * arm_timer_read_counter(). \
*/ \
asm volatile("eor %0, %1, %1\n" \
"cbnz %0, ." \
--- /dev/null
+++ b/arch/arm64/include/asm/random.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2012 ARM Ltd.
+ */
+#ifndef __ASM_RANDOM_H
+#define __ASM_RANDOM_H
+
+/* Out of line to avoid recursive include hell */
+unsigned long random_get_entropy(void);
+
+#endif
--- a/arch/arm64/include/asm/rqspinlock.h
+++ b/arch/arm64/include/asm/rqspinlock.h
@@ -2,6 +2,7 @@
#ifndef _ASM_RQSPINLOCK_H
#define _ASM_RQSPINLOCK_H
+#include <asm/arch_timer.h>
#include <asm/barrier.h>
/*
--- a/arch/arm64/include/asm/timex.h
+++ /dev/null
@@ -1,18 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-only */
-/*
- * Copyright (C) 2012 ARM Ltd.
- */
-#ifndef __ASM_TIMEX_H
-#define __ASM_TIMEX_H
-
-#include <asm/arch_timer.h>
-
-/*
- * Use the current timer as a cycle counter since this is what we use for
- * the delay loop.
- */
-#define get_cycles() arch_timer_read_counter()
-
-#include <asm-generic/timex.h>
-
-#endif
--- a/arch/arm64/kernel/time.c
+++ b/arch/arm64/kernel/time.c
@@ -29,6 +29,7 @@
#include <clocksource/arm_arch_timer.h>
+#include <asm/arch_timer.h>
#include <asm/thread_info.h>
#include <asm/paravirt.h>
@@ -52,6 +53,11 @@ unsigned long profile_pc(struct pt_regs
}
EXPORT_SYMBOL(profile_pc);
+static unsigned long random_get_entropy(void)
+{
+ return arch_timer_read_counter();
+}
+
void __init time_init(void)
{
u32 arch_timer_rate;
--- a/arch/arm64/kernel/topology.c
+++ b/arch/arm64/kernel/topology.c
@@ -21,6 +21,7 @@
#include <linux/sched/isolation.h>
#include <linux/xarray.h>
+#include <asm/arch_timer.h>
#include <asm/cpu.h>
#include <asm/cputype.h>
#include <asm/topology.h>
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -30,6 +30,7 @@
#include <linux/ubsan.h>
#include <linux/cfi.h>
+#include <asm/arch_timer.h>
#include <asm/atomic.h>
#include <asm/bug.h>
#include <asm/cpufeature.h>
--- a/arch/arm64/kvm/emulate-nested.c
+++ b/arch/arm64/kvm/emulate-nested.c
@@ -7,6 +7,7 @@
#include <linux/kvm.h>
#include <linux/kvm_host.h>
+#include <asm/arch_timer.h>
#include <asm/kvm_emulate.h>
#include <asm/kvm_nested.h>
--- a/arch/arm64/kvm/hyp/include/hyp/switch.h
+++ b/arch/arm64/kvm/hyp/include/hyp/switch.h
@@ -18,6 +18,7 @@
#include <kvm/arm_psci.h>
+#include <asm/arch_timer.h>
#include <asm/barrier.h>
#include <asm/cpufeature.h>
#include <asm/extable.h>
--- a/arch/arm64/lib/delay.c
+++ b/arch/arm64/lib/delay.c
@@ -14,6 +14,7 @@
#include <linux/timex.h>
#include <clocksource/arm_arch_timer.h>
+#include <asm/arch_timer.h>
#define USECS_TO_CYCLES(time_usecs) \
xloops_to_cycles((time_usecs) * 0x10C7UL)
--- a/drivers/irqchip/irq-apple-aic.c
+++ b/drivers/irqchip/irq-apple-aic.c
@@ -55,6 +55,7 @@
#include <linux/jump_label.h>
#include <linux/limits.h>
#include <linux/of_address.h>
+#include <asm/arch_timer.h>
#include <linux/slab.h>
#include <asm/apple_m1_pmu.h>
#include <asm/cputype.h>
^ permalink raw reply
* [patch 24/38] ARM: Select ARCH_HAS_RANDOM_ENTROPY
From: Thomas Gleixner @ 2026-04-10 12:20 UTC (permalink / raw)
To: LKML
Cc: Russell King, linux-arm-kernel, Arnd Bergmann, x86, Lu Baolu,
iommu, Michael Grzeschik, netdev, linux-wireless, Herbert Xu,
linux-crypto, Vlastimil Babka, linux-mm, David Woodhouse,
Bernie Thompson, linux-fbdev, Theodore Tso, linux-ext4,
Andrew Morton, Uladzislau Rezki, Marco Elver, Dmitry Vyukov,
kasan-dev, Andrey Ryabinin, Thomas Sailer, linux-hams,
Jason A. Donenfeld, Richard Henderson, linux-alpha,
Catalin Marinas, Huacai Chen, loongarch, Geert Uytterhoeven,
linux-m68k, Dinh Nguyen, Jonas Bonn, linux-openrisc, Helge Deller,
linux-parisc, Michael Ellerman, linuxppc-dev, Paul Walmsley,
linux-riscv, Heiko Carstens, linux-s390, David S. Miller,
sparclinux
In-Reply-To: <20260410120044.031381086@kernel.org>
The only remaining usage of get_cycles() is to provide
random_get_entropy().
Switch ARM over to the new scheme of selecting ARCH_HAS_RANDOM_ENTROPY and
providing random_get_entropy() in asm/random.h.
Remove asm/timex.h as it has no functionality anymore.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: linux-arm-kernel@lists.infradead.org
---
arch/arm/Kconfig | 1 +
arch/arm/include/asm/random.h | 14 ++++++++++++++
arch/arm/include/asm/timex.h | 18 ------------------
arch/arm/lib/delay.c | 4 ++--
4 files changed, 17 insertions(+), 20 deletions(-)
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -22,6 +22,7 @@ config ARM
select ARCH_HAS_MEMBARRIER_SYNC_CORE
select ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE
select ARCH_HAS_PTE_SPECIAL if ARM_LPAE
+ select ARCH_HAS_RANDOM_ENTROPY
select ARCH_HAS_SETUP_DMA_OPS
select ARCH_HAS_SET_MEMORY
select ARCH_STACKWALK
--- /dev/null
+++ b/arch/arm/include/asm/random.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef _ASMARM_RANDOM_H
+#define _ASMARM_RANDOM_H
+
+bool delay_read_timer(unsigned long *t);
+
+static inline unsigned long random_get_entropy(void)
+{
+ unsigned long t;
+
+ return delay_read_timer(&t) ? t : random_get_entropy_fallback();
+}
+
+#endif
--- a/arch/arm/include/asm/timex.h
+++ /dev/null
@@ -1,18 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-only */
-/*
- * arch/arm/include/asm/timex.h
- *
- * Copyright (C) 1997,1998 Russell King
- *
- * Architecture Specific TIME specifications
- */
-#ifndef _ASMARM_TIMEX_H
-#define _ASMARM_TIMEX_H
-
-// Temporary workaround
-bool delay_read_timer(unsigned long *t);
-
-#define get_cycles() ({ cycles_t c; delay_read_timer(&c) ? 0 : c; })
-#define random_get_entropy() (((unsigned long)get_cycles()) ?: random_get_entropy_fallback())
-
-#endif
--- a/arch/arm/lib/delay.c
+++ b/arch/arm/lib/delay.c
@@ -42,9 +42,9 @@ static inline u64 cyc_to_ns(u64 cyc, u32
static void __timer_delay(unsigned long cycles)
{
- cycles_t start = get_cycles();
+ cycles_t start = delay_timer->read_current_timer();
- while ((get_cycles() - start) < cycles)
+ while ((delay_timer->read_current_timer() - start) < cycles)
cpu_relax();
}
^ permalink raw reply
* [patch 23/38] alpha: Select ARCH_HAS_RANDOM_ENTROPY
From: Thomas Gleixner @ 2026-04-10 12:20 UTC (permalink / raw)
To: LKML
Cc: Richard Henderson, linux-alpha, Arnd Bergmann, x86, Lu Baolu,
iommu, Michael Grzeschik, netdev, linux-wireless, Herbert Xu,
linux-crypto, Vlastimil Babka, linux-mm, David Woodhouse,
Bernie Thompson, linux-fbdev, Theodore Tso, linux-ext4,
Andrew Morton, Uladzislau Rezki, Marco Elver, Dmitry Vyukov,
kasan-dev, Andrey Ryabinin, Thomas Sailer, linux-hams,
Jason A. Donenfeld, Russell King, linux-arm-kernel,
Catalin Marinas, Huacai Chen, loongarch, Geert Uytterhoeven,
linux-m68k, Dinh Nguyen, Jonas Bonn, linux-openrisc, Helge Deller,
linux-parisc, Michael Ellerman, linuxppc-dev, Paul Walmsley,
linux-riscv, Heiko Carstens, linux-s390, David S. Miller,
sparclinux
In-Reply-To: <20260410120044.031381086@kernel.org>
The only remaining usage of get_cycles() is to provide
random_get_entropy().
Switch alpha over to the new scheme of selecting ARCH_HAS_RANDOM_ENTROPY
and providing random_get_entropy() in asm/random.h.
Remove asm/timex.h as it has no functionality anymore.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: linux-alpha@vger.kernel.org
---
arch/alpha/Kconfig | 1 +
arch/alpha/include/asm/random.h | 14 ++++++++++++++
arch/alpha/include/asm/timex.h | 26 --------------------------
3 files changed, 15 insertions(+), 26 deletions(-)
--- a/arch/alpha/Kconfig
+++ b/arch/alpha/Kconfig
@@ -5,6 +5,7 @@ config ALPHA
select ARCH_32BIT_USTAT_F_TINODE
select ARCH_HAS_CURRENT_STACK_POINTER
select ARCH_HAS_DMA_OPS if PCI
+ select ARCH_HAS_RANDOM_ENTROPY
select ARCH_MIGHT_HAVE_PC_PARPORT
select ARCH_MIGHT_HAVE_PC_SERIO
select ARCH_MODULE_NEEDS_WEAK_PER_CPU if SMP
--- /dev/null
+++ b/arch/alpha/include/asm/random.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASMALPHA_RANDOM_H
+#define _ASMALPHA_RANDOM_H
+
+/* Use the cycle counter for entropy. */
+static inline unsigned long random_get_entropy(void)
+{
+ unsigned long ret;
+
+ __asm__ __volatile__ ("rpcc %0" : "=r"(ret));
+ return ret;
+}
+
+#endif
--- a/arch/alpha/include/asm/timex.h
+++ /dev/null
@@ -1,26 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-/*
- * linux/include/asm-alpha/timex.h
- *
- * ALPHA architecture timex specifications
- */
-#ifndef _ASMALPHA_TIMEX_H
-#define _ASMALPHA_TIMEX_H
-
-/*
- * Standard way to access the cycle counter.
- * Currently only used on SMP for scheduling.
- *
- * Only the low 32 bits are available as a continuously counting entity.
- * But this only means we'll force a reschedule every 8 seconds or so,
- * which isn't an evil thing.
- */
-static inline cycles_t get_cycles (void)
-{
- cycles_t ret;
- __asm__ __volatile__ ("rpcc %0" : "=r"(ret));
- return ret;
-}
-#define get_cycles get_cycles
-
-#endif
^ permalink raw reply
* [patch 22/38] random: Provide CONFIG_ARCH_HAS_RANDOM_ENTROPY
From: Thomas Gleixner @ 2026-04-10 12:20 UTC (permalink / raw)
To: LKML
Cc: Jason A. Donenfeld, Arnd Bergmann, x86, Lu Baolu, iommu,
Michael Grzeschik, netdev, linux-wireless, Herbert Xu,
linux-crypto, Vlastimil Babka, linux-mm, David Woodhouse,
Bernie Thompson, linux-fbdev, Theodore Tso, linux-ext4,
Andrew Morton, Uladzislau Rezki, Marco Elver, Dmitry Vyukov,
kasan-dev, Andrey Ryabinin, Thomas Sailer, linux-hams,
Richard Henderson, linux-alpha, Russell King, linux-arm-kernel,
Catalin Marinas, Huacai Chen, loongarch, Geert Uytterhoeven,
linux-m68k, Dinh Nguyen, Jonas Bonn, linux-openrisc, Helge Deller,
linux-parisc, Michael Ellerman, linuxppc-dev, Paul Walmsley,
linux-riscv, Heiko Carstens, linux-s390, David S. Miller,
sparclinux
In-Reply-To: <20260410120044.031381086@kernel.org>
Chasing down to what random_get_entropy() resolves is a 'spot the mouse'
game through a maze of #ifdeffery. Also the placement in timex.h is
non-obvious and has just been chosen because it provides conveniant access
to the underlying get_cycles() #ifdeffery.
Provide a config switch which is selectable by the architecture and a
temporary #ifdef guard in timex.h. Architectures which select the config
switch must provide asm/random.h with the architecture specific
implementation.
Update all usage sites to include linux/random.h so that the gradual
conversion does not cause build regressions.
This is part of a larger effort to remove get_cycles() usage from
non-architecture code.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: "Jason A. Donenfeld" <Jason@zx2c4.com>
---
arch/Kconfig | 3 +++
arch/loongarch/kernel/relocate.c | 1 +
arch/mips/kernel/relocate.c | 1 +
crypto/jitterentropy-kcapi.c | 1 +
include/linux/random.h | 15 +++++++++++++++
include/linux/timex.h | 2 ++
kernel/kcsan/core.c | 1 +
7 files changed, 24 insertions(+)
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -370,6 +370,9 @@ config ARCH_HAS_CPU_FINALIZE_INIT
config ARCH_HAS_DELAY_TIMER
bool
+config ARCH_HAS_RANDOM_ENTROPY
+ bool
+
# The architecture has a per-task state that includes the mm's PASID
config ARCH_HAS_CPU_PASID
bool
--- a/arch/loongarch/kernel/relocate.c
+++ b/arch/loongarch/kernel/relocate.c
@@ -9,6 +9,7 @@
#include <linux/kernel.h>
#include <linux/printk.h>
#include <linux/panic_notifier.h>
+#include <linux/random.h>
#include <linux/start_kernel.h>
#include <asm/bootinfo.h>
#include <asm/early_ioremap.h>
--- a/arch/mips/kernel/relocate.c
+++ b/arch/mips/kernel/relocate.c
@@ -19,6 +19,7 @@
#include <linux/libfdt.h>
#include <linux/of_fdt.h>
#include <linux/panic_notifier.h>
+#include <linux/random.h>
#include <linux/sched/task.h>
#include <linux/start_kernel.h>
#include <linux/string.h>
--- a/crypto/jitterentropy-kcapi.c
+++ b/crypto/jitterentropy-kcapi.c
@@ -42,6 +42,7 @@
#include <linux/fips.h>
#include <linux/kernel.h>
#include <linux/module.h>
+#include <linux/random.h>
#include <linux/slab.h>
#include <linux/time.h>
#include <crypto/internal/rng.h>
--- a/include/linux/random.h
+++ b/include/linux/random.h
@@ -139,4 +139,19 @@ int random_online_cpu(unsigned int cpu);
extern const struct file_operations random_fops, urandom_fops;
#endif
+unsigned long random_get_entropy_fallback(void);
+
+/*
+ * random_get_entropy() is used by the /dev/random driver in order to extract
+ * entropy via the relative unpredictability of when an interrupt takes places
+ * versus a high speed, fine-grained timing source or cycle counter. Since it
+ * will be occurred on every single interrupt, it must have a very low
+ * cost/overhead.
+ *
+ * If an architecture does not provide it, then use random_get_entropy_fallback().
+ */
+#ifdef CONFIG_ARCH_HAS_RANDOM_ENTROPY
+#include <asm/random.h>
+#endif
+
#endif /* _LINUX_RANDOM_H */
--- a/include/linux/timex.h
+++ b/include/linux/timex.h
@@ -66,6 +66,7 @@ unsigned long random_get_entropy_fallbac
#include <asm/timex.h>
+#ifndef CONFIG_ARCH_HAS_RANDOM_ENTROPY
#ifndef random_get_entropy
/*
* The random_get_entropy() function is used by the /dev/random driver
@@ -85,6 +86,7 @@ unsigned long random_get_entropy_fallbac
#define random_get_entropy() random_get_entropy_fallback()
#endif
#endif
+#endif
/*
* SHIFT_PLL is used as a dampening factor to define how much we
--- a/kernel/kcsan/core.c
+++ b/kernel/kcsan/core.c
@@ -18,6 +18,7 @@
#include <linux/moduleparam.h>
#include <linux/percpu.h>
#include <linux/preempt.h>
+#include <linux/random.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/uaccess.h>
^ permalink raw reply
* [patch 21/38] hamradio: baycom_epp: Remove BAYCOM_DEBUG
From: Thomas Gleixner @ 2026-04-10 12:20 UTC (permalink / raw)
To: LKML
Cc: Thomas Sailer, linux-hams, Arnd Bergmann, x86, Lu Baolu, iommu,
Michael Grzeschik, netdev, linux-wireless, Herbert Xu,
linux-crypto, Vlastimil Babka, linux-mm, David Woodhouse,
Bernie Thompson, linux-fbdev, Theodore Tso, linux-ext4,
Andrew Morton, Uladzislau Rezki, Marco Elver, Dmitry Vyukov,
kasan-dev, Andrey Ryabinin, Jason A. Donenfeld, Richard Henderson,
linux-alpha, Russell King, linux-arm-kernel, Catalin Marinas,
Huacai Chen, loongarch, Geert Uytterhoeven, linux-m68k,
Dinh Nguyen, Jonas Bonn, linux-openrisc, Helge Deller,
linux-parisc, Michael Ellerman, linuxppc-dev, Paul Walmsley,
linux-riscv, Heiko Carstens, linux-s390, David S. Miller,
sparclinux
In-Reply-To: <20260410120044.031381086@kernel.org>
The whole code guarded by BAYCOM_DEBUG is only writing debug values into a
datastructure, but there is no way to ever access them.
Remove the pointless ballast.
This is part of a larger effort to remove get_cycles() usage from
non-architecture code.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: Thomas Sailer <t.sailer@alumni.ethz.ch>
Cc: linux-hams@vger.kernel.org
---
drivers/net/hamradio/baycom_epp.c | 51 --------------------------------------
1 file changed, 51 deletions(-)
--- a/drivers/net/hamradio/baycom_epp.c
+++ b/drivers/net/hamradio/baycom_epp.c
@@ -44,7 +44,6 @@
/* --------------------------------------------------------------------- */
-#define BAYCOM_DEBUG
#define BAYCOM_MAGIC 19730510
/* --------------------------------------------------------------------- */
@@ -191,18 +190,6 @@ struct baycom_state {
unsigned int ptt_keyed;
struct sk_buff *skb; /* next transmit packet */
-
-#ifdef BAYCOM_DEBUG
- struct debug_vals {
- unsigned long last_jiffies;
- unsigned cur_intcnt;
- unsigned last_intcnt;
- int cur_pllcorr;
- int last_pllcorr;
- unsigned int mod_cycles;
- unsigned int demod_cycles;
- } debug_vals;
-#endif /* BAYCOM_DEBUG */
};
/* --------------------------------------------------------------------- */
@@ -259,26 +246,6 @@ static inline int calc_crc_ccitt(const u
#define tenms_to_flags(bc,tenms) ((tenms * bc->bitrate) / 800)
-/* --------------------------------------------------------------------- */
-
-static inline void baycom_int_freq(struct baycom_state *bc)
-{
-#ifdef BAYCOM_DEBUG
- unsigned long cur_jiffies = jiffies;
- /*
- * measure the interrupt frequency
- */
- bc->debug_vals.cur_intcnt++;
- if (time_after_eq(cur_jiffies, bc->debug_vals.last_jiffies + HZ)) {
- bc->debug_vals.last_jiffies = cur_jiffies;
- bc->debug_vals.last_intcnt = bc->debug_vals.cur_intcnt;
- bc->debug_vals.cur_intcnt = 0;
- bc->debug_vals.last_pllcorr = bc->debug_vals.cur_pllcorr;
- bc->debug_vals.cur_pllcorr = 0;
- }
-#endif /* BAYCOM_DEBUG */
-}
-
/* ---------------------------------------------------------------------- */
/*
* eppconfig_path should be setable via /proc/sys.
@@ -621,13 +588,6 @@ static int receive(struct net_device *de
return ret;
}
-/* --------------------------------------------------------------------- */
-
-#define GETTICK(x) \
-({ \
- x = (unsigned int)get_cycles(); \
-})
-
static void epp_bh(struct work_struct *work)
{
struct net_device *dev;
@@ -635,21 +595,17 @@ static void epp_bh(struct work_struct *w
struct parport *pp;
unsigned char stat;
unsigned char tmp[2];
- unsigned int time1 = 0, time2 = 0, time3 = 0;
int cnt, cnt2;
bc = container_of(work, struct baycom_state, run_work.work);
dev = bc->dev;
if (!bc->work_running)
return;
- baycom_int_freq(bc);
pp = bc->pdev->port;
/* update status */
if (pp->ops->epp_read_addr(pp, &stat, 1, 0) != 1)
goto epptimeout;
bc->stat = stat;
- bc->debug_vals.last_pllcorr = stat;
- GETTICK(time1);
if (bc->modem == EPP_FPGAEXTSTATUS) {
/* get input count */
tmp[0] = EPP_TX_FIFO_ENABLE|EPP_RX_FIFO_ENABLE|EPP_MODEM_ENABLE|1;
@@ -673,7 +629,6 @@ static void epp_bh(struct work_struct *w
goto epptimeout;
if (transmit(bc, cnt2, stat))
goto epptimeout;
- GETTICK(time2);
if (receive(dev, cnt))
goto epptimeout;
if (pp->ops->epp_read_addr(pp, &stat, 1, 0) != 1)
@@ -700,7 +655,6 @@ static void epp_bh(struct work_struct *w
}
if (transmit(bc, cnt, stat))
goto epptimeout;
- GETTICK(time2);
/* do receiver */
while ((stat & (EPP_NRAEF|EPP_NRHF)) != EPP_NRHF) {
switch (stat & (EPP_NRAEF|EPP_NRHF)) {
@@ -734,11 +688,6 @@ static void epp_bh(struct work_struct *w
goto epptimeout;
}
}
- GETTICK(time3);
-#ifdef BAYCOM_DEBUG
- bc->debug_vals.mod_cycles = time2 - time1;
- bc->debug_vals.demod_cycles = time3 - time2;
-#endif /* BAYCOM_DEBUG */
schedule_delayed_work(&bc->run_work, 1);
if (!bc->skb)
netif_wake_queue(dev);
^ permalink raw reply
* [patch 20/38] kasan: sw_tags: Replace get_cycles() by random_get_entropy()
From: Thomas Gleixner @ 2026-04-10 12:20 UTC (permalink / raw)
To: LKML
Cc: Andrey Ryabinin, kasan-dev, Arnd Bergmann, x86, Lu Baolu, iommu,
Michael Grzeschik, netdev, linux-wireless, Herbert Xu,
linux-crypto, Vlastimil Babka, linux-mm, David Woodhouse,
Bernie Thompson, linux-fbdev, Theodore Tso, linux-ext4,
Andrew Morton, Uladzislau Rezki, Marco Elver, Dmitry Vyukov,
Thomas Sailer, linux-hams, Jason A. Donenfeld, Richard Henderson,
linux-alpha, Russell King, linux-arm-kernel, Catalin Marinas,
Huacai Chen, loongarch, Geert Uytterhoeven, linux-m68k,
Dinh Nguyen, Jonas Bonn, linux-openrisc, Helge Deller,
linux-parisc, Michael Ellerman, linuxppc-dev, Paul Walmsley,
linux-riscv, Heiko Carstens, linux-s390, David S. Miller,
sparclinux
In-Reply-To: <20260410120044.031381086@kernel.org>
Seeding the random state with get_cycles() is functionally equivalent on
the architectures which provide get_cycles(), but it does not make sense
semantically.
Use random_get_entropy() instead, which is the proper interface.
This is part of a larger effort to remove get_cycles() usage from
non-architecture code.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: kasan-dev@googlegroups.com
---
mm/kasan/sw_tags.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/kasan/sw_tags.c
+++ b/mm/kasan/sw_tags.c
@@ -41,7 +41,7 @@ void __init kasan_init_sw_tags(void)
int cpu;
for_each_possible_cpu(cpu)
- per_cpu(prng_state, cpu) = (u32)get_cycles();
+ per_cpu(prng_state, cpu) = (u32)random_get_entropy();
kasan_init_tags();
kasan_enable();
^ permalink raw reply
* [patch 19/38] kcsan: Replace get_cycles() usage
From: Thomas Gleixner @ 2026-04-10 12:20 UTC (permalink / raw)
To: LKML
Cc: Marco Elver, Dmitry Vyukov, kasan-dev, Arnd Bergmann, x86,
Lu Baolu, iommu, Michael Grzeschik, netdev, linux-wireless,
Herbert Xu, linux-crypto, Vlastimil Babka, linux-mm,
David Woodhouse, Bernie Thompson, linux-fbdev, Theodore Tso,
linux-ext4, Andrew Morton, Uladzislau Rezki, Andrey Ryabinin,
Thomas Sailer, linux-hams, Jason A. Donenfeld, Richard Henderson,
linux-alpha, Russell King, linux-arm-kernel, Catalin Marinas,
Huacai Chen, loongarch, Geert Uytterhoeven, linux-m68k,
Dinh Nguyen, Jonas Bonn, linux-openrisc, Helge Deller,
linux-parisc, Michael Ellerman, linuxppc-dev, Paul Walmsley,
linux-riscv, Heiko Carstens, linux-s390, David S. Miller,
sparclinux
In-Reply-To: <20260410120044.031381086@kernel.org>
KCSAN uses get_cycles() for two purposes:
1) Seeding the random state with get_cycles() is a historical leftover.
2) The microbenchmark uses get_cycles(), which provides an unit less
counter value and is not guaranteed to be functional on all
systems/platforms.
Use random_get_entropy() for seeding the random state and ktime_get() which
is universaly functional and provides at least a comprehensible unit.
This is part of a larger effort to remove get_cycles() usage from
non-architecture code.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: Marco Elver <elver@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: kasan-dev@googlegroups.com
---
kernel/kcsan/core.c | 2 +-
kernel/kcsan/debugfs.c | 8 ++++----
2 files changed, 5 insertions(+), 5 deletions(-)
--- a/kernel/kcsan/core.c
+++ b/kernel/kcsan/core.c
@@ -798,7 +798,7 @@ void __init kcsan_init(void)
BUG_ON(!in_task());
for_each_possible_cpu(cpu)
- per_cpu(kcsan_rand_state, cpu) = (u32)get_cycles();
+ per_cpu(kcsan_rand_state, cpu) = (u32)random_get_entropy();
/*
* We are in the init task, and no other tasks should be running;
--- a/kernel/kcsan/debugfs.c
+++ b/kernel/kcsan/debugfs.c
@@ -58,7 +58,7 @@ static noinline void microbenchmark(unsi
{
const struct kcsan_ctx ctx_save = current->kcsan_ctx;
const bool was_enabled = READ_ONCE(kcsan_enabled);
- u64 cycles;
+ ktime_t nsecs;
/* We may have been called from an atomic region; reset context. */
memset(¤t->kcsan_ctx, 0, sizeof(current->kcsan_ctx));
@@ -70,16 +70,16 @@ static noinline void microbenchmark(unsi
pr_info("%s begin | iters: %lu\n", __func__, iters);
- cycles = get_cycles();
+ nsecs = ktime_get();
while (iters--) {
unsigned long addr = iters & ((PAGE_SIZE << 8) - 1);
int type = !(iters & 0x7f) ? KCSAN_ACCESS_ATOMIC :
(!(iters & 0xf) ? KCSAN_ACCESS_WRITE : 0);
__kcsan_check_access((void *)addr, sizeof(long), type);
}
- cycles = get_cycles() - cycles;
+ nsecs = ktime_get() - nsecs;
- pr_info("%s end | cycles: %llu\n", __func__, cycles);
+ pr_info("%s end | nsecs: %llu\n", __func__, nsecs);
WRITE_ONCE(kcsan_enabled, was_enabled);
/* restore context */
^ permalink raw reply
* [patch 18/38] lib/tests: Replace get_cycles() with ktime_get()
From: Thomas Gleixner @ 2026-04-10 12:19 UTC (permalink / raw)
To: LKML
Cc: Andrew Morton, Uladzislau Rezki, linux-mm, Arnd Bergmann, x86,
Lu Baolu, iommu, Michael Grzeschik, netdev, linux-wireless,
Herbert Xu, linux-crypto, Vlastimil Babka, David Woodhouse,
Bernie Thompson, linux-fbdev, Theodore Tso, linux-ext4,
Marco Elver, Dmitry Vyukov, kasan-dev, Andrey Ryabinin,
Thomas Sailer, linux-hams, Jason A. Donenfeld, Richard Henderson,
linux-alpha, Russell King, linux-arm-kernel, Catalin Marinas,
Huacai Chen, loongarch, Geert Uytterhoeven, linux-m68k,
Dinh Nguyen, Jonas Bonn, linux-openrisc, Helge Deller,
linux-parisc, Michael Ellerman, linuxppc-dev, Paul Walmsley,
linux-riscv, Heiko Carstens, linux-s390, David S. Miller,
sparclinux
In-Reply-To: <20260410120044.031381086@kernel.org>
get_cycles() is the historical access to a fine grained time source, but it
is a suboptimal choice for two reasons:
- get_cycles() is not guaranteed to be supported and functional on all
systems/platforms. If not supported or not functional it returns 0,
which makes benchmarking moot.
- get_cycles() returns the raw counter value of whatever the
architecture platform provides. The original x86 Time Stamp Counter
(TSC) was despite its name tied to the actual CPU core frequency.
That's not longer the case. So the counter value is only meaningful
when the CPU operates at the same frequency as the TSC or the value is
adjusted to the actual CPU frequency. Other architectures and
platforms provide similar disjunct counters via get_cycles(), so the
result is operations per BOGO-cycles, which is not really meaningful.
Use ktime_get() instead which provides nanosecond timestamps with the
granularity of the underlying hardware counter, which is not different to
the variety of get_cycles() implementations.
This provides at least understandable metrics, i.e. operations/nanoseconds,
and is available on all platforms. As with get_cycles() the result might
have to be put into relation with the CPU operating frequency, but that's
not any different.
This is part of a larger effort to remove get_cycles() usage from
non-architecture code.
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Uladzislau Rezki <urezki@gmail.com>
Cc: linux-mm@kvack.org
---
lib/interval_tree_test.c | 16 ++++++++--------
lib/rbtree_test.c | 46 +++++++++++++++++++++++-----------------------
lib/test_vmalloc.c | 10 +++++-----
3 files changed, 36 insertions(+), 36 deletions(-)
--- a/lib/interval_tree_test.c
+++ b/lib/interval_tree_test.c
@@ -65,13 +65,13 @@ static void init(void)
static int basic_check(void)
{
int i, j;
- cycles_t time1, time2, time;
+ ktime_t time1, time2, time;
printk(KERN_ALERT "interval tree insert/remove");
init();
- time1 = get_cycles();
+ time1 = ktime_get();
for (i = 0; i < perf_loops; i++) {
for (j = 0; j < nnodes; j++)
@@ -80,11 +80,11 @@ static int basic_check(void)
interval_tree_remove(nodes + j, &root);
}
- time2 = get_cycles();
+ time2 = ktime_get();
time = time2 - time1;
time = div_u64(time, perf_loops);
- printk(" -> %llu cycles\n", (unsigned long long)time);
+ printk(" -> %llu nsecs\n", (unsigned long long)time);
return 0;
}
@@ -93,7 +93,7 @@ static int search_check(void)
{
int i, j;
unsigned long results;
- cycles_t time1, time2, time;
+ ktime_t time1, time2, time;
printk(KERN_ALERT "interval tree search");
@@ -102,7 +102,7 @@ static int search_check(void)
for (j = 0; j < nnodes; j++)
interval_tree_insert(nodes + j, &root);
- time1 = get_cycles();
+ time1 = ktime_get();
results = 0;
for (i = 0; i < search_loops; i++)
@@ -113,12 +113,12 @@ static int search_check(void)
results += search(&root, start, last);
}
- time2 = get_cycles();
+ time2 = ktime_get();
time = time2 - time1;
time = div_u64(time, search_loops);
results = div_u64(results, search_loops);
- printk(" -> %llu cycles (%lu results)\n",
+ printk(" -> %llu nsecs (%lu results)\n",
(unsigned long long)time, results);
for (j = 0; j < nnodes; j++)
--- a/lib/rbtree_test.c
+++ b/lib/rbtree_test.c
@@ -243,14 +243,14 @@ static void check_augmented(int nr_nodes
static int basic_check(void)
{
int i, j;
- cycles_t time1, time2, time;
+ ktime_t time1, time2, time;
struct rb_node *node;
printk(KERN_ALERT "rbtree testing");
init();
- time1 = get_cycles();
+ time1 = ktime_get();
for (i = 0; i < perf_loops; i++) {
for (j = 0; j < nnodes; j++)
@@ -259,14 +259,14 @@ static int basic_check(void)
erase(nodes + j, &root);
}
- time2 = get_cycles();
+ time2 = ktime_get();
time = time2 - time1;
time = div_u64(time, perf_loops);
- printk(" -> test 1 (latency of nnodes insert+delete): %llu cycles\n",
+ printk(" -> test 1 (latency of nnodes insert+delete): %llu nsecs\n",
(unsigned long long)time);
- time1 = get_cycles();
+ time1 = ktime_get();
for (i = 0; i < perf_loops; i++) {
for (j = 0; j < nnodes; j++)
@@ -275,52 +275,52 @@ static int basic_check(void)
erase_cached(nodes + j, &root);
}
- time2 = get_cycles();
+ time2 = ktime_get();
time = time2 - time1;
time = div_u64(time, perf_loops);
- printk(" -> test 2 (latency of nnodes cached insert+delete): %llu cycles\n",
+ printk(" -> test 2 (latency of nnodes cached insert+delete): %llu nsecs\n",
(unsigned long long)time);
for (i = 0; i < nnodes; i++)
insert(nodes + i, &root);
- time1 = get_cycles();
+ time1 = ktime_get();
for (i = 0; i < perf_loops; i++) {
for (node = rb_first(&root.rb_root); node; node = rb_next(node))
;
}
- time2 = get_cycles();
+ time2 = ktime_get();
time = time2 - time1;
time = div_u64(time, perf_loops);
- printk(" -> test 3 (latency of inorder traversal): %llu cycles\n",
+ printk(" -> test 3 (latency of inorder traversal): %llu nsecs\n",
(unsigned long long)time);
- time1 = get_cycles();
+ time1 = ktime_get();
for (i = 0; i < perf_loops; i++)
node = rb_first(&root.rb_root);
- time2 = get_cycles();
+ time2 = ktime_get();
time = time2 - time1;
time = div_u64(time, perf_loops);
printk(" -> test 4 (latency to fetch first node)\n");
- printk(" non-cached: %llu cycles\n", (unsigned long long)time);
+ printk(" non-cached: %llu nsecs\n", (unsigned long long)time);
- time1 = get_cycles();
+ time1 = ktime_get();
for (i = 0; i < perf_loops; i++)
node = rb_first_cached(&root);
- time2 = get_cycles();
+ time2 = ktime_get();
time = time2 - time1;
time = div_u64(time, perf_loops);
- printk(" cached: %llu cycles\n", (unsigned long long)time);
+ printk(" cached: %llu nsecs\n", (unsigned long long)time);
for (i = 0; i < nnodes; i++)
erase(nodes + i, &root);
@@ -345,13 +345,13 @@ static int basic_check(void)
static int augmented_check(void)
{
int i, j;
- cycles_t time1, time2, time;
+ ktime_t time1, time2, time;
printk(KERN_ALERT "augmented rbtree testing");
init();
- time1 = get_cycles();
+ time1 = ktime_get();
for (i = 0; i < perf_loops; i++) {
for (j = 0; j < nnodes; j++)
@@ -360,13 +360,13 @@ static int augmented_check(void)
erase_augmented(nodes + j, &root);
}
- time2 = get_cycles();
+ time2 = ktime_get();
time = time2 - time1;
time = div_u64(time, perf_loops);
- printk(" -> test 1 (latency of nnodes insert+delete): %llu cycles\n", (unsigned long long)time);
+ printk(" -> test 1 (latency of nnodes insert+delete): %llu nsecs\n", (unsigned long long)time);
- time1 = get_cycles();
+ time1 = ktime_get();
for (i = 0; i < perf_loops; i++) {
for (j = 0; j < nnodes; j++)
@@ -375,11 +375,11 @@ static int augmented_check(void)
erase_augmented_cached(nodes + j, &root);
}
- time2 = get_cycles();
+ time2 = ktime_get();
time = time2 - time1;
time = div_u64(time, perf_loops);
- printk(" -> test 2 (latency of nnodes cached insert+delete): %llu cycles\n", (unsigned long long)time);
+ printk(" -> test 2 (latency of nnodes cached insert+delete): %llu nsecs\n", (unsigned long long)time);
for (i = 0; i < check_loops; i++) {
init();
--- a/lib/test_vmalloc.c
+++ b/lib/test_vmalloc.c
@@ -454,8 +454,8 @@ static struct test_driver {
struct task_struct *task;
struct test_case_data data[ARRAY_SIZE(test_case_array)];
- unsigned long start;
- unsigned long stop;
+ ktime_t start;
+ ktime_t stop;
} *tdriver;
static void shuffle_array(int *arr, int n)
@@ -490,7 +490,7 @@ static int test_func(void *private)
*/
synchronize_srcu(&prepare_for_test_srcu);
- t->start = get_cycles();
+ t->start = ktime_get();
for (i = 0; i < ARRAY_SIZE(test_case_array); i++) {
index = random_array[i];
@@ -519,7 +519,7 @@ static int test_func(void *private)
t->data[index].time = delta;
}
- t->stop = get_cycles();
+ t->stop = ktime_get();
test_report_one_done();
/*
@@ -619,7 +619,7 @@ static void do_concurrent_test(void)
t->data[j].time);
}
- pr_info("All test took worker%d=%lu cycles\n",
+ pr_info("All test took worker%d=%lld nsecs\n",
i, t->stop - t->start);
}
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