From: Thomas Gleixner <tglx@kernel•org>
To: LKML <linux-kernel@vger•kernel.org>
Cc: Arnd Bergmann <arnd@arndb•de>,
x86@kernel•org, Lu Baolu <baolu.lu@linux•intel.com>,
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Subject: [patch V1.1 11/38] misc: sgi-gru: Remove get_cycles() [ab]use
Date: Fri, 10 Apr 2026 22:56:11 +0200 [thread overview]
Message-ID: <87ik9yzg9g.ffs@tglx> (raw)
In-Reply-To: <20260410120318.320727701@kernel.org>
Calculating a timeout from get_cycles() is a historical leftover without
any functional requirement.
Use ktime_get() instead.
Signed-off-by: Thomas Gleixner <tglx@kernel•org>
---
V2: Fix typo
---
drivers/misc/sgi-gru/gruhandles.c | 20 ++++++++------------
drivers/misc/sgi-gru/grukservices.c | 3 ++-
drivers/misc/sgi-gru/grutlbpurge.c | 5 ++---
3 files changed, 12 insertions(+), 16 deletions(-)
--- a/drivers/misc/sgi-gru/gruhandles.c
+++ b/drivers/misc/sgi-gru/gruhandles.c
@@ -6,26 +6,22 @@
*/
#include <linux/kernel.h>
+#include <linux/timekeeping.h>
#include "gru.h"
#include "grulib.h"
#include "grutables.h"
-/* 10 sec */
#include <linux/sync_core.h>
-#include <asm/tsc.h>
-#define GRU_OPERATION_TIMEOUT ((cycles_t) tsc_khz*10*1000)
-#define CLKS2NSEC(c) ((c) * 1000000 / tsc_khz)
+
+#define GRU_OPERATION_TIMEOUT_NSEC (((ktime_t)10 * NSEC_PER_SEC))
/* Extract the status field from a kernel handle */
#define GET_MSEG_HANDLE_STATUS(h) (((*(unsigned long *)(h)) >> 16) & 3)
struct mcs_op_statistic mcs_op_statistics[mcsop_last];
-static void update_mcs_stats(enum mcs_op op, unsigned long clks)
+static void update_mcs_stats(enum mcs_op op, unsigned long nsec)
{
- unsigned long nsec;
-
- nsec = CLKS2NSEC(clks);
atomic_long_inc(&mcs_op_statistics[op].count);
atomic_long_add(nsec, &mcs_op_statistics[op].total);
if (mcs_op_statistics[op].max < nsec)
@@ -58,21 +54,21 @@ static void report_instruction_timeout(v
static int wait_instruction_complete(void *h, enum mcs_op opc)
{
+ ktime_t start_time = ktime_get();
int status;
- unsigned long start_time = get_cycles();
while (1) {
cpu_relax();
status = GET_MSEG_HANDLE_STATUS(h);
if (status != CCHSTATUS_ACTIVE)
break;
- if (GRU_OPERATION_TIMEOUT < (get_cycles() - start_time)) {
+ if (GRU_OPERATION_TIMEOUT_NSEC < (ktime_get() - start_time)) {
report_instruction_timeout(h);
- start_time = get_cycles();
+ start_time = ktime_get();
}
}
if (gru_options & OPT_STATS)
- update_mcs_stats(opc, get_cycles() - start_time);
+ update_mcs_stats(opc, (unsigned long)(ktime_get() - start_time));
return status;
}
--- a/drivers/misc/sgi-gru/grukservices.c
+++ b/drivers/misc/sgi-gru/grukservices.c
@@ -20,6 +20,7 @@
#include <linux/uaccess.h>
#include <linux/delay.h>
#include <linux/export.h>
+#include <linux/random.h>
#include <asm/io_apic.h>
#include "gru.h"
#include "grulib.h"
@@ -1106,7 +1107,7 @@ static int quicktest3(unsigned long arg)
int ret = 0;
memset(buf2, 0, sizeof(buf2));
- memset(buf1, get_cycles() & 255, sizeof(buf1));
+ memset(buf1, get_random_u32() & 255, sizeof(buf1));
gru_copy_gpa(uv_gpa(buf2), uv_gpa(buf1), BUFSIZE);
if (memcmp(buf1, buf2, BUFSIZE)) {
printk(KERN_DEBUG "GRU:%d quicktest3 error\n", smp_processor_id());
--- a/drivers/misc/sgi-gru/grutlbpurge.c
+++ b/drivers/misc/sgi-gru/grutlbpurge.c
@@ -22,13 +22,12 @@
#include <linux/delay.h>
#include <linux/timex.h>
#include <linux/srcu.h>
+#include <linux/random.h>
#include <asm/processor.h>
#include "gru.h"
#include "grutables.h"
#include <asm/uv/uv_hub.h>
-#define gru_random() get_cycles()
-
/* ---------------------------------- TLB Invalidation functions --------
* get_tgh_handle
*
@@ -49,7 +48,7 @@ static inline int get_off_blade_tgh(stru
int n;
n = GRU_NUM_TGH - gru->gs_tgh_first_remote;
- n = gru_random() % n;
+ n = get_random_u32() % n;
n += gru->gs_tgh_first_remote;
return n;
}
next prev parent reply other threads:[~2026-04-10 20:56 UTC|newest]
Thread overview: 69+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-10 12:18 [patch 00/38] treewide: Cleanup LATCH, CLOCK_TICK_RATE and get_cycles() [ab]use Thomas Gleixner
2026-04-10 12:18 ` [patch 01/38] percpu: Sanitize __percpu_qual include hell Thomas Gleixner
2026-04-10 12:18 ` [patch 02/38] x86: Cleanup include recursion hell Thomas Gleixner
2026-04-10 20:55 ` [patch V1.1 " Thomas Gleixner
2026-04-10 12:18 ` [patch 03/38] x86/apm: Remove last LATCH usage Thomas Gleixner
2026-04-10 12:18 ` [patch 04/38] x86: Use PIT_TICK_RATE instead of CLOCK_TICK_RATE Thomas Gleixner
2026-04-10 12:18 ` [patch 05/38] treewide: Remove CLOCK_TICK_RATE Thomas Gleixner
2026-04-15 6:40 ` Christophe Leroy (CS GROUP)
2026-04-16 11:22 ` Geert Uytterhoeven
2026-04-10 12:18 ` [patch 06/38] calibrate: Rework delay timer calibration Thomas Gleixner
2026-04-10 12:19 ` [patch 07/38] treewide: Consolidate cycles_t Thomas Gleixner
2026-04-13 9:15 ` Ojaswin Mujoo
2026-04-15 6:43 ` Christophe Leroy (CS GROUP)
2026-04-16 19:32 ` Thomas Gleixner
2026-04-16 11:22 ` Geert Uytterhoeven
2026-04-10 12:19 ` [patch 08/38] x86/tsc: Use rdtsc() instead of get_cycles() Thomas Gleixner
2026-04-10 12:19 ` [patch 09/38] iommu/vt-d: Use sched_clock() " Thomas Gleixner
2026-04-10 13:45 ` Baolu Lu
2026-04-10 15:14 ` Thomas Gleixner
2026-04-10 12:19 ` [patch 10/38] arcnet: Remove function timing code Thomas Gleixner
2026-04-13 15:29 ` David Woodhouse
2026-04-10 12:19 ` [patch 11/38] misc: sgi-gru: Remove get_cycles() [ab]use Thomas Gleixner
2026-04-10 20:56 ` Thomas Gleixner [this message]
2026-04-10 12:19 ` [patch 12/38] wifi: wil6210: Replace get_cyles() usage Thomas Gleixner
2026-04-10 12:19 ` [patch 13/38] crypto: tcrypt: Replace get_cycles() with ktime_get() Thomas Gleixner
2026-04-10 12:19 ` [patch 14/38] slub: Use prandom instead of get_cycles() Thomas Gleixner
2026-04-10 12:19 ` [patch 15/38] ptp: ptp_vmclock: Replace get_cycles() usage Thomas Gleixner
2026-04-13 15:33 ` David Woodhouse
2026-04-13 19:30 ` Arnd Bergmann
2026-04-10 12:19 ` [patch 16/38] fbdev: udlfb: Replace get_cycles() with ktime_get() Thomas Gleixner
2026-04-10 12:19 ` [patch 17/38] ext4: Replace get_cycles() usage " Thomas Gleixner
2026-04-13 14:46 ` Arnd Bergmann
2026-04-10 12:19 ` [patch 18/38] lib/tests: Replace get_cycles() " Thomas Gleixner
2026-04-16 10:24 ` Geert Uytterhoeven
2026-04-10 12:20 ` [patch 19/38] kcsan: Replace get_cycles() usage Thomas Gleixner
2026-04-10 13:39 ` Marco Elver
2026-04-10 12:20 ` [patch 20/38] kasan: sw_tags: Replace get_cycles() by random_get_entropy() Thomas Gleixner
2026-04-10 12:20 ` [patch 21/38] hamradio: baycom_epp: Remove BAYCOM_DEBUG Thomas Gleixner
2026-04-10 12:20 ` [patch 22/38] random: Provide CONFIG_ARCH_HAS_RANDOM_ENTROPY Thomas Gleixner
2026-04-10 12:20 ` [patch 23/38] alpha: Select ARCH_HAS_RANDOM_ENTROPY Thomas Gleixner
2026-04-12 13:22 ` Magnus Lindholm
2026-04-10 12:20 ` [patch 24/38] ARM: " Thomas Gleixner
2026-04-10 12:20 ` [patch 25/38] arm64: " Thomas Gleixner
2026-04-10 12:20 ` [patch 26/38] loongarch: " Thomas Gleixner
2026-04-10 12:20 ` [patch 27/38] m68k: " Thomas Gleixner
2026-04-10 15:31 ` Daniel Palmer
2026-04-16 11:22 ` Geert Uytterhoeven
2026-04-10 12:20 ` [patch 28/38] mips: " Thomas Gleixner
2026-04-13 5:47 ` Maciej W. Rozycki
2026-04-10 12:20 ` [patch 29/38] nios2: " Thomas Gleixner
2026-04-10 12:20 ` [patch 30/38] openrisc: " Thomas Gleixner
2026-04-12 8:56 ` Stafford Horne
2026-04-10 12:21 ` [patch 31/38] parisc: " Thomas Gleixner
2026-04-14 12:41 ` Helge Deller
2026-04-10 12:21 ` [patch 32/38] powerpc/spufs: Use mftb() directly Thomas Gleixner
2026-04-13 14:43 ` Arnd Bergmann
2026-04-15 6:38 ` Christophe Leroy (CS GROUP)
2026-04-21 6:48 ` Mukesh Kumar Chaurasiya
2026-04-10 12:21 ` [patch 33/38] powerpc: Select ARCH_HAS_RANDOM_ENTROPY Thomas Gleixner
2026-04-15 6:47 ` Christophe Leroy (CS GROUP)
2026-04-21 11:22 ` Mukesh Kumar Chaurasiya
2026-04-10 12:21 ` [patch 34/38] riscv: " Thomas Gleixner
2026-04-10 12:21 ` [patch 35/38] s390: " Thomas Gleixner
2026-04-16 13:42 ` Heiko Carstens
2026-04-16 19:29 ` Thomas Gleixner
2026-04-10 12:21 ` [patch 36/38] sparc: Select ARCH_HAS_RANDOM_ENTROPY for SPARC64 Thomas Gleixner
2026-04-10 12:21 ` [patch 37/38] x86: Select ARCH_HAS_RANDOM_ENTROPY Thomas Gleixner
2026-04-10 12:21 ` [patch 38/38] treewide: Remove asm/timex.h includes from generic code Thomas Gleixner
2026-04-13 14:45 ` Arnd Bergmann
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