[PATCH v4 02/10] arm_mpam: propagate MSC access errors for hw_probe functions
From: Andre Przywara
Date: Thu Jul 23 2026 - 12:04:17 EST
Allow the functions probing for MSC hardware and features to return an
error, and propagate read and write errors from the lower level up.
This uses some "scoped cleanup" functions like scoped_guard() and
ACQUIRE() to avoid the complexity of error handling when a lock has been
taken. Since the mon_sel_lock is a bit special (even more so in an
upcoming patch), we define a new GUARD type for it.
Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
---
drivers/resctrl/mpam_devices.c | 127 +++++++++++++++++++++-----------
drivers/resctrl/mpam_internal.h | 8 ++
2 files changed, 91 insertions(+), 44 deletions(-)
diff --git a/drivers/resctrl/mpam_devices.c b/drivers/resctrl/mpam_devices.c
index 912c21ce7f9f..ecd45a585942 100644
--- a/drivers/resctrl/mpam_devices.c
+++ b/drivers/resctrl/mpam_devices.c
@@ -794,38 +794,46 @@ static bool mpam_ris_hw_probe_csu_nrdy(struct mpam_msc_ris *ris)
bool can_set, can_clear;
struct mpam_msc *msc = ris->vmsc->msc;
- if (WARN_ON_ONCE(!mpam_mon_sel_lock(msc)))
+ ACQUIRE(mon_sel_lock, guard)(msc);
+ if (ACQUIRE_ERR(mon_sel_lock, &guard))
return false;
mon_sel = FIELD_PREP(MSMON_CFG_MON_SEL_MON_SEL, 0) |
FIELD_PREP(MSMON_CFG_MON_SEL_RIS, ris->ris_idx);
- mpam_write_monsel_reg(msc, CFG_MON_SEL, mon_sel);
+ if (mpam_write_monsel_reg(msc, CFG_MON_SEL, mon_sel))
+ return false;
/* Hardware might ignore nrdy if it's not enabled */
ctl_val = MSMON_CFG_CSU_CTL_TYPE_CSU;
ctl_val |= MSMON_CFG_x_CTL_MATCH_PARTID;
ctl_val |= MSMON_CFG_x_CTL_MATCH_PMG;
ctl_val |= MSMON_CFG_x_CTL_EN;
- mpam_write_monsel_reg(msc, CFG_CSU_FLT, 0);
- mpam_write_monsel_reg(msc, CFG_CSU_CTL, ctl_val);
+ if (mpam_write_monsel_reg(msc, CFG_CSU_FLT, 0))
+ return false;
+ if (mpam_write_monsel_reg(msc, CFG_CSU_CTL, ctl_val))
+ return false;
- _mpam_write_monsel_reg(msc, MSMON_CSU, MSMON___NRDY);
- _mpam_read_monsel_reg(msc, MSMON_CSU, &now);
+ if (_mpam_write_monsel_reg(msc, MSMON_CSU, MSMON___NRDY))
+ return false;
+ if (_mpam_read_monsel_reg(msc, MSMON_CSU, &now))
+ return false;
can_set = now & MSMON___NRDY;
- _mpam_write_monsel_reg(msc, MSMON_CSU, 0);
+ if (_mpam_write_monsel_reg(msc, MSMON_CSU, 0))
+ return false;
/* Configuration change to try and coax hardware into setting nrdy */
- mpam_write_monsel_reg(msc, CFG_CSU_FLT, 0x1);
- _mpam_read_monsel_reg(msc, MSMON_CSU, &now);
+ if (mpam_write_monsel_reg(msc, CFG_CSU_FLT, 0x1))
+ return false;
+ if (_mpam_read_monsel_reg(msc, MSMON_CSU, &now))
+ return false;
can_clear = !(now & MSMON___NRDY);
- mpam_mon_sel_unlock(msc);
return (!can_set || !can_clear);
}
-static void mpam_ris_hw_probe(struct mpam_msc_ris *ris)
+static int mpam_ris_hw_probe(struct mpam_msc_ris *ris)
{
- int err;
+ int fw_has_nrdy_err, err;
struct mpam_msc *msc = ris->vmsc->msc;
struct device *dev = &msc->pdev->dev;
struct mpam_props *props = &ris->props;
@@ -838,7 +846,9 @@ static void mpam_ris_hw_probe(struct mpam_msc_ris *ris)
if (FIELD_GET(MPAMF_IDR_HAS_CCAP_PART, ris->idr)) {
u32 ccap_features;
- mpam_read_partsel_reg(msc, CCAP_IDR, &ccap_features);
+ err = mpam_read_partsel_reg(msc, CCAP_IDR, &ccap_features);
+ if (err)
+ return err;
props->cmax_wd = FIELD_GET(MPAMF_CCAP_IDR_CMAX_WD, ccap_features);
if (props->cmax_wd &&
@@ -863,7 +873,9 @@ static void mpam_ris_hw_probe(struct mpam_msc_ris *ris)
if (FIELD_GET(MPAMF_IDR_HAS_CPOR_PART, ris->idr)) {
u32 cpor_features;
- mpam_read_partsel_reg(msc, CPOR_IDR, &cpor_features);
+ err = mpam_read_partsel_reg(msc, CPOR_IDR, &cpor_features);
+ if (err)
+ return err;
props->cpbm_wd = FIELD_GET(MPAMF_CPOR_IDR_CPBM_WD, cpor_features);
if (props->cpbm_wd)
@@ -873,8 +885,9 @@ static void mpam_ris_hw_probe(struct mpam_msc_ris *ris)
/* Memory bandwidth partitioning */
if (FIELD_GET(MPAMF_IDR_HAS_MBW_PART, ris->idr)) {
u32 mbw_features;
-
- mpam_read_partsel_reg(msc, MBW_IDR, &mbw_features);
+ err = mpam_read_partsel_reg(msc, MBW_IDR, &mbw_features);
+ if (err)
+ return err;
/* portion bitmap resolution */
props->mbw_pbm_bits = FIELD_GET(MPAMF_MBW_IDR_BWPBM_WD, mbw_features);
@@ -903,8 +916,9 @@ static void mpam_ris_hw_probe(struct mpam_msc_ris *ris)
/* Priority partitioning */
if (FIELD_GET(MPAMF_IDR_HAS_PRI_PART, ris->idr)) {
u32 pri_features;
-
- mpam_read_partsel_reg(msc, PRI_IDR, &pri_features);
+ err = mpam_read_partsel_reg(msc, PRI_IDR, &pri_features);
+ if (err)
+ return err;
props->intpri_wd = FIELD_GET(MPAMF_PRI_IDR_INTPRI_WD, pri_features);
if (props->intpri_wd && FIELD_GET(MPAMF_PRI_IDR_HAS_INTPRI, pri_features)) {
@@ -925,20 +939,24 @@ static void mpam_ris_hw_probe(struct mpam_msc_ris *ris)
if (FIELD_GET(MPAMF_IDR_HAS_MSMON, ris->idr)) {
u32 msmon_features;
- mpam_read_partsel_reg(msc, MSMON_IDR, &msmon_features);
+ err = mpam_read_partsel_reg(msc, MSMON_IDR, &msmon_features);
+ if (err)
+ return err;
/*
* If the firmware max-nrdy-us property is missing, the
* CSU counters can't be used. Should we wait forever?
*/
- err = device_property_read_u32(&msc->pdev->dev,
- "arm,not-ready-us",
- &msc->nrdy_usec);
+ fw_has_nrdy_err = device_property_read_u32(&msc->pdev->dev,
+ "arm,not-ready-us",
+ &msc->nrdy_usec);
if (FIELD_GET(MPAMF_MSMON_IDR_MSMON_CSU, msmon_features)) {
u32 csumonidr;
- mpam_read_partsel_reg(msc, CSUMON_IDR, &csumonidr);
+ err = mpam_read_partsel_reg(msc, CSUMON_IDR, &csumonidr);
+ if (err)
+ return err;
props->num_csu_mon = FIELD_GET(MPAMF_CSUMON_IDR_NUM_MON, csumonidr);
if (props->num_csu_mon) {
@@ -956,7 +974,7 @@ static void mpam_ris_hw_probe(struct mpam_msc_ris *ris)
* Accept the missing firmware property if NRDY appears
* un-implemented.
*/
- if (err && hw_managed)
+ if (fw_has_nrdy_err && hw_managed)
dev_err_once(dev, "Counters are not usable because not-ready timeout was not provided by firmware.");
}
}
@@ -964,7 +982,9 @@ static void mpam_ris_hw_probe(struct mpam_msc_ris *ris)
bool has_long;
u32 mbwumon_idr;
- mpam_read_partsel_reg(msc, MBWUMON_IDR, &mbwumon_idr);
+ err = mpam_read_partsel_reg(msc, MBWUMON_IDR, &mbwumon_idr);
+ if (err)
+ return err;
props->num_mbwu_mon = FIELD_GET(MPAMF_MBWUMON_IDR_NUM_MON, mbwumon_idr);
if (props->num_mbwu_mon) {
@@ -997,16 +1017,22 @@ static void mpam_ris_hw_probe(struct mpam_msc_ris *ris)
u16 partid_max;
u32 nrwidr;
- mpam_read_partsel_reg(msc, PARTID_NRW_IDR, &nrwidr);
+ err = mpam_read_partsel_reg(msc, PARTID_NRW_IDR, &nrwidr);
+ if (err)
+ return err;
+
partid_max = FIELD_GET(MPAMF_PARTID_NRW_IDR_INTPARTID_MAX, nrwidr);
mpam_set_feature(mpam_feat_partid_nrw, props);
msc->partid_max = min(msc->partid_max, partid_max);
}
+
+ return 0;
}
static int mpam_msc_hw_probe(struct mpam_msc *msc)
{
+ int ret;
u64 idr;
u16 partid_max;
u8 ris_idx, pmg_max;
@@ -1021,11 +1047,14 @@ static int mpam_msc_hw_probe(struct mpam_msc *msc)
}
/* Grab an IDR value to find out how many RIS there are */
- mutex_lock(&msc->part_sel_lock);
- mpam_msc_read_idr(msc, &idr);
- mpam_read_partsel_reg(msc, IIDR, &msc->iidr);
-
- mutex_unlock(&msc->part_sel_lock);
+ scoped_guard(mutex, &msc->part_sel_lock) {
+ ret = mpam_msc_read_idr(msc, &idr);
+ if (ret)
+ return ret;
+ ret = mpam_read_partsel_reg(msc, IIDR, &msc->iidr);
+ if (ret)
+ return ret;
+ }
mpam_enable_quirks(msc);
@@ -1036,10 +1065,15 @@ static int mpam_msc_hw_probe(struct mpam_msc *msc)
msc->pmg_max = FIELD_GET(MPAMF_IDR_PMG_MAX, idr);
for (ris_idx = 0; ris_idx <= msc->ris_max; ris_idx++) {
- mutex_lock(&msc->part_sel_lock);
- __mpam_part_sel(ris_idx, 0, msc);
- mpam_msc_read_idr(msc, &idr);
- mutex_unlock(&msc->part_sel_lock);
+ scoped_guard(mutex, &msc->part_sel_lock) {
+ ret = __mpam_part_sel(ris_idx, 0, msc);
+ if (ret)
+ return ret;
+
+ ret = mpam_msc_read_idr(msc, &idr);
+ if (ret)
+ return ret;
+ }
partid_max = FIELD_GET(MPAMF_IDR_PARTID_MAX, idr);
pmg_max = FIELD_GET(MPAMF_IDR_PMG_MAX, idr);
@@ -1047,17 +1081,22 @@ static int mpam_msc_hw_probe(struct mpam_msc *msc)
msc->pmg_max = min(msc->pmg_max, pmg_max);
msc->has_extd_esr = FIELD_GET(MPAMF_IDR_HAS_EXTD_ESR, idr);
- mutex_lock(&mpam_list_lock);
- ris = mpam_get_or_create_ris(msc, ris_idx);
- mutex_unlock(&mpam_list_lock);
- if (IS_ERR(ris))
- return PTR_ERR(ris);
+ scoped_guard(mutex, &mpam_list_lock) {
+ ris = mpam_get_or_create_ris(msc, ris_idx);
+ if (IS_ERR(ris))
+ return PTR_ERR(ris);
+ }
ris->idr = idr;
- mutex_lock(&msc->part_sel_lock);
- __mpam_part_sel(ris_idx, 0, msc);
- mpam_ris_hw_probe(ris);
- mutex_unlock(&msc->part_sel_lock);
+ scoped_guard(mutex, &msc->part_sel_lock) {
+ ret = __mpam_part_sel(ris_idx, 0, msc);
+ if (ret)
+ return ret;
+
+ ret = mpam_ris_hw_probe(ris);
+ if (ret)
+ return ret;
+ }
}
/* Clear any stale errors */
diff --git a/drivers/resctrl/mpam_internal.h b/drivers/resctrl/mpam_internal.h
index 04d1a59f02af..0c3f6a040b20 100644
--- a/drivers/resctrl/mpam_internal.h
+++ b/drivers/resctrl/mpam_internal.h
@@ -162,6 +162,14 @@ static inline void mpam_mon_sel_lock_init(struct mpam_msc *msc)
raw_spin_lock_init(&msc->_mon_sel_lock);
}
+DEFINE_GUARD(mon_sel,
+ struct mpam_msc *,
+ mpam_mon_sel_lock(_T),
+ mpam_mon_sel_unlock(_T));
+DEFINE_GUARD_COND(mon_sel, _lock,
+ mpam_mon_sel_lock(_T),
+ _RET);
+
/* Bits for mpam features bitmaps */
enum mpam_device_features {
mpam_feat_cpor_part,
--
2.43.0