From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8380C4A206F; Thu, 15 Oct 2026 13:44:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792071843; cv=none; b=XZ2PFWQcPm5lyK26M873t0Frmy+vy4dLvdwP0MNPfCA+aS62pGCFQgwoar/2goZW+PmHPHYsXNC1bbZDuPbd0mymAnNVSaRcJVWkqKYcK9E2vIVBdPwc2IV0QmNq+eNDAcM3E7epqIjbD4xQnaE6TfZeXju3XdCrj32P/REN0vw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792071843; c=relaxed/simple; bh=p6ELrmae6qI9vb1c7UWuKd4wsKeLvtU/xgInuHBF/dE=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=UlqY5XdgsIzkB3J82UOR3yH1yMAqAxJmQhCoUVKlV3kbHWvPGVxtaZ6ZTDHnifipiOYGiU2pV7DkxEfnTfP4IBFj/ebJYzChbm/r/HylP2g9xsd+4m1s9hycMbUssMqO0JeaV3bVBYBfUS2/CYJGDUws7JMEf7nvfjwetJ1t9T8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=exGXaKVB; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="exGXaKVB" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8F3F21F000C4; Thu, 15 Oct 2026 13:44:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792071842; bh=I2p+U5+wUh22N+M/aKWINw3olgc5ack8LcssI64gIEc=; h=From:To:Cc:Subject:In-Reply-To:References:Date; b=exGXaKVBAvRgexBQ/j+3luClBUh4HWab4IeJnWLhL/T0H+Y1azArlmYT+dpTn4lu8 x+gr/9z6swgjBRgc2ZY6nZVGn7nr21uwebXV6z+VmSrm04Jd067qww7PMGdlSGoTLx irTR4HKsIsL+XVyyKNxid4eLp1e84A5390GXxUHkLg60TcDtTmL/39K0SO2F7ISkaZ R8jfq1pLLCks+r4+ALybXiFI+jgoDY/ra8xlMwgoirXb1or+0i6xQfKptTDXeXDE+q Sq/MGy+5TuTK6m5YAxzwc9C8taRfAlUKxZ3W3GRpwzuw17G4lKjIhkUahwu8eme6Ea EbwptDdkNvzHg== From: Thomas Gleixner To: Thomas =?utf-8?Q?Wei=C3=9Fschuh?= , Andy Lutomirski , Vincenzo Frascino , Shuah Khan Cc: linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Thomas =?utf-8?Q?Wei=C3=9Fschuh?= Subject: Re: [PATCH v2 2/3] vdso/gettimeofday: Add support for CLOCK_BOOTTIME_ALARM In-Reply-To: <20260929-vdso-alarm-clocks-v2-2-a7af4089a698@weissschuh.net> References: <20260929-vdso-alarm-clocks-v2-0-a7af4089a698@weissschuh.net> <20260929-vdso-alarm-clocks-v2-2-a7af4089a698@weissschuh.net> Date: Thu, 15 Oct 2026 15:43:59 +0200 Message-ID: <87ld7zdqow.ffs@fw13> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable On Tue, Sep 29 2026 at 22:24, Thomas Wei=C3=9Fschuh wrote: > CLOCK_BOOTTIME_ALARM behaves exactly as CLOCK_BOOTTIME as far as the > vDSO is concerned. The vDSO library can handle it automatically > correctly. Only the basetime needs to be maintained during the tick. > > The namespace offset is already set correctly, although it was not > used before. > > Reuse the CLOCK_BOOTTIME basetime for CLOCK_BOOTTIME_ALARM and update > the userspace hres clock mask to include CLOCK_BOOTTIME_ALARM. It behaves the same way, but ALARM clock IDs require a RTC device. See alarm_clock_get_timespec(). So the VDSO and the syscall will disagree when there is no RTC available... Thanks, tglx