hwpstate{_amd,intel}(4): Move common knobs to a separate file

Reason for doing this right now is to resolve the conflict on
'machdep.hwpstate_pkg_ctrl' between the Intel and AMD drivers, even
though I expect to remove it for hwpstate_amd(4) at some point.

More generally, this is going to be useful for some future code
factorization.  Also, the 'debug.hwpstate_verbose' knob was moved there,
as we'll likely want to use it for the Intel driver as well (which is
currently not the case).

Note for MFC: Will be partial, since `hwpstate_amd(4)` does not support
CPPC in stable/15 nor stable/14.

Reviewed by:    emaste
Fixes:          3e6e4e4a0d ("hwpstate: add CPPC support for pstate driver on AMD")
MFC after:      2 weeks
Differential Revision:  https://reviews.freebsd.org/D54528

sys/conf/files.x86

@@ -342,6 +342,7 @@ x86/acpica/srat.c		optional	acpi
 x86/bios/vpd.c			optional	vpd
 x86/cpufreq/est.c		optional	cpufreq
 x86/cpufreq/hwpstate_amd.c	optional	cpufreq
+x86/cpufreq/hwpstate_common.c	optional	cpufreq
 x86/cpufreq/hwpstate_intel.c	optional	cpufreq
 x86/cpufreq/p4tcc.c		optional	cpufreq
 x86/cpufreq/powernow.c		optional	cpufreq

sys/modules/cpufreq/Makefile

@@ -9,7 +9,8 @@ SRCS+=	bus_if.h cpufreq_if.h device_if.h pci_if.h
 .PATH:	${SRCTOP}/sys/x86/cpufreq
 
 SRCS+=	acpi_if.h opt_acpi.h
-SRCS+=	est.c hwpstate_amd.c p4tcc.c powernow.c hwpstate_intel.c
+SRCS+=	est.c p4tcc.c powernow.c
+SRCS+=	hwpstate_amd.c hwpstate_common.c hwpstate_intel.c
 .endif
 
 .if ${MACHINE} == "i386"

sys/x86/cpufreq/hwpstate_amd.c

@@ -68,6 +68,8 @@
 
 #include <dev/acpica/acpivar.h>
 
+#include <x86/cpufreq/hwpstate_common.h>
+
 #include "acpi_if.h"
 #include "cpufreq_if.h"
 
@@ -162,10 +164,6 @@ static int	hwpstate_get_info_from_acpi_perf(device_t dev, device_t perf_dev);
 static int	hwpstate_get_info_from_msr(device_t dev);
 static int	hwpstate_goto_pstate(device_t dev, int pstate_id);
 
-static int	hwpstate_verbose;
-SYSCTL_INT(_debug, OID_AUTO, hwpstate_verbose, CTLFLAG_RWTUN,
-    &hwpstate_verbose, 0, "Debug hwpstate");
-
 static int	hwpstate_verify;
 SYSCTL_INT(_debug, OID_AUTO, hwpstate_verify, CTLFLAG_RWTUN,
     &hwpstate_verify, 0, "Verify P-state after setting");
@@ -176,11 +174,6 @@ SYSCTL_BOOL(_debug, OID_AUTO, hwpstate_pstate_limit, CTLFLAG_RWTUN,
     "If enabled (1), limit administrative control of P-states to the value in "
     "CurPstateLimit");
 
-static bool hwpstate_pkg_ctrl_enable = true;
-SYSCTL_BOOL(_machdep, OID_AUTO, hwpstate_pkg_ctrl, CTLFLAG_RDTUN,
-    &hwpstate_pkg_ctrl_enable, 0,
-    "Set 1 (default) to enable package-level control, 0 to disable");
-
 static bool hwpstate_amd_cppc_enable = true;
 SYSCTL_BOOL(_machdep, OID_AUTO, hwpstate_amd_cppc_enable, CTLFLAG_RDTUN,
     &hwpstate_amd_cppc_enable, 0,

sys/x86/cpufreq/hwpstate_common.c

@@ -0,0 +1,22 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2026 The FreeBSD Foundation
+ *
+ * This software was developed by Olivier Certner <olce@FreeBSD.org> at Kumacom
+ * SARL under sponsorship from the FreeBSD Foundation.
+ */
+
+#include <sys/sysctl.h>
+
+#include <x86/cpufreq/hwpstate_common.h>
+
+
+int hwpstate_verbose;
+SYSCTL_INT(_debug, OID_AUTO, hwpstate_verbose, CTLFLAG_RWTUN,
+    &hwpstate_verbose, 0, "Debug hwpstate");
+
+bool hwpstate_pkg_ctrl_enable = true;
+SYSCTL_BOOL(_machdep, OID_AUTO, hwpstate_pkg_ctrl, CTLFLAG_RDTUN,
+    &hwpstate_pkg_ctrl_enable, 0,
+    "Set 1 (default) to enable package-level control, 0 to disable");

sys/x86/cpufreq/hwpstate_common.h

@@ -0,0 +1,13 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2026 The FreeBSD Foundation
+ *
+ * This software was developed by Olivier Certner <olce@FreeBSD.org> at Kumacom
+ * SARL under sponsorship from the FreeBSD Foundation.
+ */
+
+/* Stuff common to hwpstate_amd(4) and hwpstate_intel(4). */
+
+extern int hwpstate_verbose;
+extern bool hwpstate_pkg_ctrl_enable;

sys/x86/cpufreq/hwpstate_intel.c

@@ -48,6 +48,7 @@
 
 #include <dev/acpica/acpivar.h>
 
+#include <x86/cpufreq/hwpstate_common.h>
 #include <x86/cpufreq/hwpstate_intel_internal.h>
 
 #include "acpi_if.h"
@@ -108,11 +109,6 @@ static driver_t hwpstate_intel_driver = {
 DRIVER_MODULE(hwpstate_intel, cpu, hwpstate_intel_driver, NULL, NULL);
 MODULE_VERSION(hwpstate_intel, 1);
 
-static bool hwpstate_pkg_ctrl_enable = true;
-SYSCTL_BOOL(_machdep, OID_AUTO, hwpstate_pkg_ctrl, CTLFLAG_RDTUN,
-    &hwpstate_pkg_ctrl_enable, 0,
-    "Set 1 (default) to enable package-level control, 0 to disable");
-
 static int
 intel_hwp_dump_sysctl_handler(SYSCTL_HANDLER_ARGS)
 {