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Merge tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux

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Pull arm64 MPAM fixes from Catalin Marinas:

 - Fix NULL dereference and a false-positive warning when the driver
   probes hardware with surprising version numbers

 - Fix writing values to the wrong registers when probing
   cache-utilisation counters. Replace 'NRDY' probing with a version
   that is robust for platforms where the bit is writeable by both
   hardware and software

* tag 'arm64-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux:
  arm_mpam: Check whether the config array is allocated before destroying it
  arm_mpam: Fix false positive assert failure during mpam_disable()
  arm_mpam: Improve check for whether or not NRDY is hardware managed
  arm_mpam: Pretend that NRDY is always hardware managed
  arm_mpam: Fix monitor instance selection when checking for hardware NRDY
This commit is contained in:
Linus Torvalds
2026-05-15 15:40:25 -07:00
parent 30e0ff6d6a 6ccbb613b4
commit 36343a8ff3
2 changed files with 40 additions and 43 deletions
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81
drivers/resctrl/mpam_devices.c
View File

@@ -164,11 +164,17 @@ static void mpam_free_garbage(void)
/*
* Once mpam is enabled, new requestors cannot further reduce the available
* partid. Assert that the size is fixed, and new requestors will be turned
* away.
* away. This is needed when walking over structures sized by PARTID.
*
* During mpam_disable() these structures are not fixed, but the MSC state
* is still reset using whatever sizes have been discovered so far. As only
* PARTID 0 will be used after mpam_disable(), any race would be benign.
* Skip the check if a mpam_disable_reason has been set.
*/
static void mpam_assert_partid_sizes_fixed(void)
{
WARN_ON_ONCE(!partid_max_published);
if (!mpam_disable_reason)
WARN_ON_ONCE(!partid_max_published);
}
static u32 __mpam_read_reg(struct mpam_msc *msc, u16 reg)
@@ -728,10 +734,9 @@ static void mpam_enable_quirks(struct mpam_msc *msc)
* Try and see what values stick in this bit. If we can write either value,
* its probably not implemented by hardware.
*/
static bool _mpam_ris_hw_probe_hw_nrdy(struct mpam_msc_ris *ris, u32 mon_reg)
static bool mpam_ris_hw_probe_csu_nrdy(struct mpam_msc_ris *ris)
{
u32 now;
u64 mon_sel;
u32 now, mon_sel, ctl_val;
bool can_set, can_clear;
struct mpam_msc *msc = ris->vmsc->msc;
@@ -740,23 +745,30 @@ static bool _mpam_ris_hw_probe_hw_nrdy(struct mpam_msc_ris *ris, u32 mon_reg)
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, mon_reg, mon_sel);
mpam_write_monsel_reg(msc, CFG_MON_SEL, mon_sel);
_mpam_write_monsel_reg(msc, mon_reg, MSMON___NRDY);
now = _mpam_read_monsel_reg(msc, mon_reg);
/* 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);
_mpam_write_monsel_reg(msc, MSMON_CSU, MSMON___NRDY);
now = _mpam_read_monsel_reg(msc, MSMON_CSU);
can_set = now & MSMON___NRDY;
_mpam_write_monsel_reg(msc, mon_reg, 0);
now = _mpam_read_monsel_reg(msc, mon_reg);
_mpam_write_monsel_reg(msc, MSMON_CSU, 0);
/* Configuration change to try and coax hardware into setting nrdy */
mpam_write_monsel_reg(msc, CFG_CSU_FLT, 0x1);
now = _mpam_read_monsel_reg(msc, MSMON_CSU);
can_clear = !(now & MSMON___NRDY);
mpam_mon_sel_unlock(msc);
return (!can_set || !can_clear);
}
#define mpam_ris_hw_probe_hw_nrdy(_ris, _mon_reg) \
_mpam_ris_hw_probe_hw_nrdy(_ris, MSMON_##_mon_reg)
static void mpam_ris_hw_probe(struct mpam_msc_ris *ris)
{
int err;
@@ -873,20 +885,18 @@ static void mpam_ris_hw_probe(struct mpam_msc_ris *ris)
mpam_set_feature(mpam_feat_msmon_csu_xcl, props);
/* Is NRDY hardware managed? */
hw_managed = mpam_ris_hw_probe_hw_nrdy(ris, CSU);
if (hw_managed)
mpam_set_feature(mpam_feat_msmon_csu_hw_nrdy, props);
}
hw_managed = mpam_ris_hw_probe_csu_nrdy(ris);
/*
* Accept the missing firmware property if NRDY appears
* un-implemented.
*/
if (err && mpam_has_feature(mpam_feat_msmon_csu_hw_nrdy, props))
dev_err_once(dev, "Counters are not usable because not-ready timeout was not provided by firmware.");
/*
* Accept the missing firmware property if NRDY appears
* un-implemented.
*/
if (err && hw_managed)
dev_err_once(dev, "Counters are not usable because not-ready timeout was not provided by firmware.");
}
}
if (FIELD_GET(MPAMF_MSMON_IDR_MSMON_MBWU, msmon_features)) {
bool has_long, hw_managed;
bool has_long;
u32 mbwumon_idr = mpam_read_partsel_reg(msc, MBWUMON_IDR);
props->num_mbwu_mon = FIELD_GET(MPAMF_MBWUMON_IDR_NUM_MON, mbwumon_idr);
@@ -905,16 +915,6 @@ static void mpam_ris_hw_probe(struct mpam_msc_ris *ris)
} else {
mpam_set_feature(mpam_feat_msmon_mbwu_31counter, props);
}
/* Is NRDY hardware managed? */
hw_managed = mpam_ris_hw_probe_hw_nrdy(ris, MBWU);
if (hw_managed)
mpam_set_feature(mpam_feat_msmon_mbwu_hw_nrdy, props);
/*
* Don't warn about any missing firmware property for
* MBWU NRDY - it doesn't make any sense!
*/
}
}
}
@@ -1197,7 +1197,6 @@ static void __ris_msmon_read(void *arg)
bool reset_on_next_read = false;
struct mpam_msc_ris *ris = m->ris;
struct msmon_mbwu_state *mbwu_state;
struct mpam_props *rprops = &ris->props;
struct mpam_msc *msc = m->ris->vmsc->msc;
u32 mon_sel, ctl_val, flt_val, cur_ctl, cur_flt;
@@ -1253,8 +1252,7 @@ static void __ris_msmon_read(void *arg)
switch (m->type) {
case mpam_feat_msmon_csu:
now = mpam_read_monsel_reg(msc, CSU);
if (mpam_has_feature(mpam_feat_msmon_csu_hw_nrdy, rprops))
nrdy = now & MSMON___NRDY;
nrdy = now & MSMON___NRDY;
now = FIELD_GET(MSMON___VALUE, now);
if (mpam_has_quirk(IGNORE_CSU_NRDY, msc) && m->waited_timeout)
@@ -1266,8 +1264,7 @@ static void __ris_msmon_read(void *arg)
case mpam_feat_msmon_mbwu_63counter:
if (m->type != mpam_feat_msmon_mbwu_31counter) {
now = mpam_msc_read_mbwu_l(msc);
if (mpam_has_feature(mpam_feat_msmon_mbwu_hw_nrdy, rprops))
nrdy = now & MSMON___L_NRDY;
nrdy = now & MSMON___L_NRDY;
if (m->type == mpam_feat_msmon_mbwu_63counter)
now = FIELD_GET(MSMON___LWD_VALUE, now);
@@ -1275,8 +1272,7 @@ static void __ris_msmon_read(void *arg)
now = FIELD_GET(MSMON___L_VALUE, now);
} else {
now = mpam_read_monsel_reg(msc, MBWU);
if (mpam_has_feature(mpam_feat_msmon_mbwu_hw_nrdy, rprops))
nrdy = now & MSMON___NRDY;
nrdy = now & MSMON___NRDY;
now = FIELD_GET(MSMON___VALUE, now);
}
@@ -2585,6 +2581,9 @@ static void __destroy_component_cfg(struct mpam_component *comp)
lockdep_assert_held(&mpam_list_lock);
if (!comp->cfg)
return;
add_to_garbage(comp->cfg);
list_for_each_entry(vmsc, &comp->vmsc, comp_list) {
msc = vmsc->msc;

2
drivers/resctrl/mpam_internal.h
View File

@@ -181,14 +181,12 @@ enum mpam_device_features {
mpam_feat_msmon_csu,
mpam_feat_msmon_csu_capture,
mpam_feat_msmon_csu_xcl,
mpam_feat_msmon_csu_hw_nrdy,
mpam_feat_msmon_mbwu,
mpam_feat_msmon_mbwu_31counter,
mpam_feat_msmon_mbwu_44counter,
mpam_feat_msmon_mbwu_63counter,
mpam_feat_msmon_mbwu_capture,
mpam_feat_msmon_mbwu_rwbw,
mpam_feat_msmon_mbwu_hw_nrdy,
mpam_feat_partid_nrw,
MPAM_FEATURE_LAST
};