linux-kernel - Re: [PATCH v3 3/3] rust: time: Add ktime

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250610.171506.1930082951902279512.fujita.tomonori@gmail.com>
Date: Tue, 10 Jun 2025 17:15:06 +0900 (JST)
From: FUJITA Tomonori <fujita.tomonori@...il.com>
To: a.hindborg@...nel.org
Cc: fujita.tomonori@...il.com, alex.gaynor@...il.com, ojeda@...nel.org,
 aliceryhl@...gle.com, anna-maria@...utronix.de, bjorn3_gh@...tonmail.com,
 boqun.feng@...il.com, dakr@...nel.org, frederic@...nel.org,
 gary@...yguo.net, jstultz@...gle.com, linux-kernel@...r.kernel.org,
 lossin@...nel.org, lyude@...hat.com, rust-for-linux@...r.kernel.org,
 sboyd@...nel.org, tglx@...utronix.de, tmgross@...ch.edu
Subject: Re: [PATCH v3 3/3] rust: time: Add ktime_get() to ClockSource trait

On Tue, 10 Jun 2025 10:01:57 +0200
Andreas Hindborg <a.hindborg@...nel.org> wrote:

> "FUJITA Tomonori" <fujita.tomonori@...il.com> writes:
> 
>> Introduce the ktime_get() associated function to the ClockSource
>> trait, allowing each clock source to specify how it retrieves the
>> current time. This enables Instant::now() to be implemented
>> generically using the type-level ClockSource abstraction.
>>
>> This change enhances the type safety and extensibility of timekeeping
>> by statically associating time retrieval mechanisms with their
>> respective clock types. It also reduces the reliance on hardcoded
>> clock logic within Instant.
>>
>> Reviewed-by: Andreas Hindborg <a.hindborg@...nel.org>
>> Signed-off-by: FUJITA Tomonori <fujita.tomonori@...il.com>
>> ---
>>  rust/helpers/helpers.c |  1 +
>>  rust/helpers/time.c    | 18 ++++++++++++++++++
>>  rust/kernel/time.rs    | 32 ++++++++++++++++++++++++++++----
>>  3 files changed, 47 insertions(+), 4 deletions(-)
>>  create mode 100644 rust/helpers/time.c
>>
>> diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c
>> index 0f1b5d115985..0613a849e05c 100644
>> --- a/rust/helpers/helpers.c
>> +++ b/rust/helpers/helpers.c
>> @@ -39,6 +39,7 @@
>>  #include "spinlock.c"
>>  #include "sync.c"
>>  #include "task.c"
>> +#include "time.c"
>>  #include "uaccess.c"
>>  #include "vmalloc.c"
>>  #include "wait.c"
>> diff --git a/rust/helpers/time.c b/rust/helpers/time.c
>> new file mode 100644
>> index 000000000000..9c296e93a560
>> --- /dev/null
>> +++ b/rust/helpers/time.c
>> @@ -0,0 +1,18 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +
>> +#include <linux/timekeeping.h>
>> +
>> +ktime_t rust_helper_ktime_get_real(void)
>> +{
>> +	return ktime_get_with_offset(TK_OFFS_REAL);
>> +}
>> +
>> +ktime_t rust_helper_ktime_get_boottime(void)
>> +{
>> +	return ktime_get_with_offset(TK_OFFS_BOOT);
>> +}
>> +
>> +ktime_t rust_helper_ktime_get_clocktai(void)
>> +{
>> +	return ktime_get_with_offset(TK_OFFS_TAI);
>> +}
> 
> This just caught my eye. I think policy is to make helpers as much 1:1 as
> possible. We should not inject arguments here. Instead, we should have
> just one function that passes the argument along.

Indeed, you're right. It should have been as follows:

+++ b/rust/helpers/time.c
@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/timekeeping.h>
+
+ktime_t rust_helper_ktime_get_real(void)
+{
+	return ktime_get_real();
+}
+
+ktime_t rust_helper_ktime_get_boottime(void)
+{
+	return ktime_get_boottime();
+}
+
+ktime_t rust_helper_ktime_get_clocktai(void)
+{
+	return ktime_get_clocktai();
+}

I'll send v4 shortly.