[PATCH V2 06/13] perf/x86/intel/uncore: Add domain global init callback

From: Zide Chen

Date: Wed Dec 31 2025 - 17:49:43 EST


In the Intel uncore self-describing mechanism, the Global Control
Register freeze_all bit is SoC-wide and propagates to all uncore PMUs.

On Diamond Rapids, this bit is set at power-on, unlike some prior
platforms. Add a global_init callback to unfreeze all PMON units.

Signed-off-by: Zide Chen <zide.chen@xxxxxxxxx>
---
V2: New patch

arch/x86/events/intel/uncore.c | 16 ++++++++++++++++
arch/x86/events/intel/uncore.h | 2 ++
arch/x86/events/intel/uncore_discovery.c | 3 +++
3 files changed, 21 insertions(+)

diff --git a/arch/x86/events/intel/uncore.c b/arch/x86/events/intel/uncore.c
index 1565c0418fb1..080b6870a88d 100644
--- a/arch/x86/events/intel/uncore.c
+++ b/arch/x86/events/intel/uncore.c
@@ -1697,6 +1697,21 @@ static int __init uncore_mmio_init(void)
return ret;
}

+static int uncore_mmio_global_init(u64 ctl)
+{
+ void __iomem *io_addr;
+
+ io_addr = ioremap(ctl, sizeof(ctl));
+ if (!io_addr)
+ return -ENOMEM;
+
+ /* Clear bit 0, all other bits are reserved */
+ writel(0, io_addr);
+
+ iounmap(io_addr);
+ return 0;
+}
+
static const struct uncore_plat_init nhm_uncore_init __initconst = {
.cpu_init = nhm_uncore_cpu_init,
};
@@ -1839,6 +1854,7 @@ static const struct uncore_plat_init dmr_uncore_init __initconst = {
.domain[0].units_ignore = dmr_uncore_imh_units_ignore,
.domain[1].discovery_base = CBB_UNCORE_DISCOVERY_MSR,
.domain[1].units_ignore = dmr_uncore_cbb_units_ignore,
+ .domain[1].global_init = uncore_mmio_global_init,
};

static const struct uncore_plat_init generic_uncore_init __initconst = {
diff --git a/arch/x86/events/intel/uncore.h b/arch/x86/events/intel/uncore.h
index 83d01a9cefc0..55e3aebf4b5e 100644
--- a/arch/x86/events/intel/uncore.h
+++ b/arch/x86/events/intel/uncore.h
@@ -51,6 +51,8 @@ struct uncore_discovery_domain {
/* MSR address or PCI device used as the discovery base */
u32 discovery_base;
bool base_is_pci;
+ int (*global_init)(u64 ctl);
+
/* The units in the discovery table should be ignored. */
int *units_ignore;
};
diff --git a/arch/x86/events/intel/uncore_discovery.c b/arch/x86/events/intel/uncore_discovery.c
index 6f409e0b4722..3a5a3876b74c 100644
--- a/arch/x86/events/intel/uncore_discovery.c
+++ b/arch/x86/events/intel/uncore_discovery.c
@@ -286,6 +286,9 @@ static int __parse_discovery_table(struct uncore_discovery_domain *domain,
if (!io_addr)
return -ENOMEM;

+ if (domain->global_init && domain->global_init(global.ctl))
+ return -ENODEV;
+
/* Parsing Unit Discovery State */
for (i = 0; i < global.max_units; i++) {
memcpy_fromio(&unit, io_addr + (i + 1) * (global.stride * 8),
--
2.52.0