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

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Message-ID: <20251231224233.113839-7-zide.chen@intel.com>
Date: Wed, 31 Dec 2025 14:42:23 -0800
From: Zide Chen <zide.chen@...el.com>
To: Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...hat.com>,
	Arnaldo Carvalho de Melo <acme@...nel.org>,
	Namhyung Kim <namhyung@...nel.org>,
	Ian Rogers <irogers@...gle.com>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Andi Kleen <ak@...ux.intel.com>,
	Eranian Stephane <eranian@...gle.com>
Cc: linux-kernel@...r.kernel.org,
	linux-perf-users@...r.kernel.org,
	Dapeng Mi <dapeng1.mi@...ux.intel.com>,
	Zide Chen <zide.chen@...el.com>,
	Xudong Hao <xudong.hao@...el.com>,
	Falcon Thomas <thomas.falcon@...el.com>
Subject: [PATCH V2 06/13] perf/x86/intel/uncore: Add domain global init callback

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@...el.com>
---
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