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Wysocki" , Daniel Lezcano Cc: Zhang Rui , Lukasz Luba , Srinivas Pandruvada , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 05/12] powercap: intel_rapl: Use shifts for power-of-2 operations Date: Thu, 12 Feb 2026 15:30:37 -0800 Message-ID: <20260212233044.329790-6-sathyanarayanan.kuppuswamy@linux.intel.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260212233044.329790-1-sathyanarayanan.kuppuswamy@linux.intel.com> References: <20260212233044.329790-1-sathyanarayanan.kuppuswamy@linux.intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Replace division by (1 << value) with shift operations for clarity and consistency. Add ULL suffix to avoid undefined behavior from shifting signed integers. No functional changes intended. Signed-off-by: Kuppuswamy Sathyanarayanan Acked-by: Srinivas Pandruvada --- drivers/powercap/intel_rapl_common.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/drivers/powercap/intel_rapl_common.c b/drivers/powercap/intel_= rapl_common.c index 74a74af8f0ec..819eab3988da 100644 --- a/drivers/powercap/intel_rapl_common.c +++ b/drivers/powercap/intel_rapl_common.c @@ -964,13 +964,13 @@ static int rapl_check_unit_core(struct rapl_domain *r= d) } =20 value =3D (ra.value & ENERGY_UNIT_MASK) >> ENERGY_UNIT_OFFSET; - rd->energy_unit =3D ENERGY_UNIT_SCALE * 1000000 / (1 << value); + rd->energy_unit =3D (ENERGY_UNIT_SCALE * 1000000) >> value; =20 value =3D (ra.value & POWER_UNIT_MASK) >> POWER_UNIT_OFFSET; - rd->power_unit =3D 1000000 / (1 << value); + rd->power_unit =3D 1000000 >> value; =20 value =3D (ra.value & TIME_UNIT_MASK) >> TIME_UNIT_OFFSET; - rd->time_unit =3D 1000000 / (1 << value); + rd->time_unit =3D 1000000 >> value; =20 pr_debug("Core CPU %s:%s energy=3D%dpJ, time=3D%dus, power=3D%duW\n", rd->rp->name, rd->name, rd->energy_unit, rd->time_unit, rd->power_unit); @@ -992,13 +992,13 @@ static int rapl_check_unit_atom(struct rapl_domain *r= d) } =20 value =3D (ra.value & ENERGY_UNIT_MASK) >> ENERGY_UNIT_OFFSET; - rd->energy_unit =3D ENERGY_UNIT_SCALE * 1 << value; + rd->energy_unit =3D ENERGY_UNIT_SCALE * (1ULL << value); =20 value =3D (ra.value & POWER_UNIT_MASK) >> POWER_UNIT_OFFSET; - rd->power_unit =3D (1 << value) * 1000; + rd->power_unit =3D (1ULL << value) * 1000; =20 value =3D (ra.value & TIME_UNIT_MASK) >> TIME_UNIT_OFFSET; - rd->time_unit =3D 1000000 / (1 << value); + rd->time_unit =3D 1000000 >> value; =20 pr_debug("Atom %s:%s energy=3D%dpJ, time=3D%dus, power=3D%duW\n", rd->rp->name, rd->name, rd->energy_unit, rd->time_unit, rd->power_unit); @@ -1121,7 +1121,7 @@ static u64 rapl_compute_time_window_core(struct rapl_= domain *rd, u64 value, if (!to_raw) { f =3D (value & 0x60) >> 5; y =3D value & 0x1f; - value =3D (1 << y) * (4 + f) * rd->time_unit / 4; + value =3D (1ULL << y) * (4 + f) * rd->time_unit / 4; } else { if (value < rd->time_unit) return 0; @@ -1169,13 +1169,13 @@ static int rapl_check_unit_tpmi(struct rapl_domain = *rd) } =20 value =3D (ra.value & TPMI_ENERGY_UNIT_MASK) >> TPMI_ENERGY_UNIT_OFFSET; - rd->energy_unit =3D ENERGY_UNIT_SCALE * 1000000 / (1 << value); + rd->energy_unit =3D (ENERGY_UNIT_SCALE * 1000000) >> value; =20 value =3D (ra.value & TPMI_POWER_UNIT_MASK) >> TPMI_POWER_UNIT_OFFSET; - rd->power_unit =3D 1000000 / (1 << value); + rd->power_unit =3D 1000000 >> value; =20 value =3D (ra.value & TPMI_TIME_UNIT_MASK) >> TPMI_TIME_UNIT_OFFSET; - rd->time_unit =3D 1000000 / (1 << value); + rd->time_unit =3D 1000000 >> value; =20 pr_debug("Core CPU %s:%s energy=3D%dpJ, time=3D%dus, power=3D%duW\n", rd->rp->name, rd->name, rd->energy_unit, rd->time_unit, rd->power_unit); --=20 2.43.0