1 files changed, 238 insertions, 0 deletions
diff --git a/arch/x86/kernel/acpi/cstate.c b/arch/x86/kernel/acpi/cstate.c
new file mode 100644
index 0000000000..401808b47a
--- /dev/null
+++ b/arch/x86/kernel/acpi/cstate.c
@@ -0,0 +1,238 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2005 Intel Corporation
+ * 	Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
+ * 	- Added _PDC for SMP C-states on Intel CPUs
+ */
+
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/init.h>
+#include <linux/acpi.h>
+#include <linux/cpu.h>
+#include <linux/sched.h>
+
+#include <acpi/processor.h>
+#include <asm/mwait.h>
+#include <asm/special_insns.h>
+
+/*
+ * Initialize bm_flags based on the CPU cache properties
+ * On SMP it depends on cache configuration
+ * - When cache is not shared among all CPUs, we flush cache
+ *   before entering C3.
+ * - When cache is shared among all CPUs, we use bm_check
+ *   mechanism as in UP case
+ *
+ * This routine is called only after all the CPUs are online
+ */
+void acpi_processor_power_init_bm_check(struct acpi_processor_flags *flags,
+					unsigned int cpu)
+{
+	struct cpuinfo_x86 *c = &cpu_data(cpu);
+
+	flags->bm_check = 0;
+	if (num_online_cpus() == 1)
+		flags->bm_check = 1;
+	else if (c->x86_vendor == X86_VENDOR_INTEL) {
+		/*
+		 * Today all MP CPUs that support C3 share cache.
+		 * And caches should not be flushed by software while
+		 * entering C3 type state.
+		 */
+		flags->bm_check = 1;
+	}
+
+	/*
+	 * On all recent Intel platforms, ARB_DISABLE is a nop.
+	 * So, set bm_control to zero to indicate that ARB_DISABLE
+	 * is not required while entering C3 type state on
+	 * P4, Core and beyond CPUs
+	 */
+	if (c->x86_vendor == X86_VENDOR_INTEL &&
+	    (c->x86 > 0xf || (c->x86 == 6 && c->x86_model >= 0x0f)))
+			flags->bm_control = 0;
+
+	if (c->x86_vendor == X86_VENDOR_CENTAUR) {
+		if (c->x86 > 6 || (c->x86 == 6 && c->x86_model == 0x0f &&
+		    c->x86_stepping >= 0x0e)) {
+			/*
+			 * For all recent Centaur CPUs, the ucode will make sure that each
+			 * core can keep cache coherence with each other while entering C3
+			 * type state. So, set bm_check to 1 to indicate that the kernel
+			 * doesn't need to execute a cache flush operation (WBINVD) when
+			 * entering C3 type state.
+			 */
+			flags->bm_check = 1;
+			/*
+			 * For all recent Centaur platforms, ARB_DISABLE is a nop.
+			 * Set bm_control to zero to indicate that ARB_DISABLE is
+			 * not required while entering C3 type state.
+			 */
+			flags->bm_control = 0;
+		}
+	}
+
+	if (c->x86_vendor == X86_VENDOR_ZHAOXIN) {
+		/*
+		 * All Zhaoxin CPUs that support C3 share cache.
+		 * And caches should not be flushed by software while
+		 * entering C3 type state.
+		 */
+		flags->bm_check = 1;
+		/*
+		 * On all recent Zhaoxin platforms, ARB_DISABLE is a nop.
+		 * So, set bm_control to zero to indicate that ARB_DISABLE
+		 * is not required while entering C3 type state.
+		 */
+		flags->bm_control = 0;
+	}
+	if (c->x86_vendor == X86_VENDOR_AMD && c->x86 >= 0x17) {
+		/*
+		 * For all AMD Zen or newer CPUs that support C3, caches
+		 * should not be flushed by software while entering C3
+		 * type state. Set bm->check to 1 so that kernel doesn't
+		 * need to execute cache flush operation.
+		 */
+		flags->bm_check = 1;
+		/*
+		 * In current AMD C state implementation ARB_DIS is no longer
+		 * used. So set bm_control to zero to indicate ARB_DIS is not
+		 * required while entering C3 type state.
+		 */
+		flags->bm_control = 0;
+	}
+}
+EXPORT_SYMBOL(acpi_processor_power_init_bm_check);
+
+/* The code below handles cstate entry with monitor-mwait pair on Intel*/
+
+struct cstate_entry {
+	struct {
+		unsigned int eax;
+		unsigned int ecx;
+	} states[ACPI_PROCESSOR_MAX_POWER];
+};
+static struct cstate_entry __percpu *cpu_cstate_entry;	/* per CPU ptr */
+
+static short mwait_supported[ACPI_PROCESSOR_MAX_POWER];
+
+#define NATIVE_CSTATE_BEYOND_HALT	(2)
+
+static long acpi_processor_ffh_cstate_probe_cpu(void *_cx)
+{
+	struct acpi_processor_cx *cx = _cx;
+	long retval;
+	unsigned int eax, ebx, ecx, edx;
+	unsigned int edx_part;
+	unsigned int cstate_type; /* C-state type and not ACPI C-state type */
+	unsigned int num_cstate_subtype;
+
+	cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx);
+
+	/* Check whether this particular cx_type (in CST) is supported or not */
+	cstate_type = ((cx->address >> MWAIT_SUBSTATE_SIZE) &
+			MWAIT_CSTATE_MASK) + 1;
+	edx_part = edx >> (cstate_type * MWAIT_SUBSTATE_SIZE);
+	num_cstate_subtype = edx_part & MWAIT_SUBSTATE_MASK;
+
+	retval = 0;
+	/* If the HW does not support any sub-states in this C-state */
+	if (num_cstate_subtype == 0) {
+		pr_warn(FW_BUG "ACPI MWAIT C-state 0x%x not supported by HW (0x%x)\n",
+				cx->address, edx_part);
+		retval = -1;
+		goto out;
+	}
+
+	/* mwait ecx extensions INTERRUPT_BREAK should be supported for C2/C3 */
+	if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) ||
+	    !(ecx & CPUID5_ECX_INTERRUPT_BREAK)) {
+		retval = -1;
+		goto out;
+	}
+
+	if (!mwait_supported[cstate_type]) {
+		mwait_supported[cstate_type] = 1;
+		printk(KERN_DEBUG
+			"Monitor-Mwait will be used to enter C-%d state\n",
+			cx->type);
+	}
+	snprintf(cx->desc,
+			ACPI_CX_DESC_LEN, "ACPI FFH MWAIT 0x%x",
+			cx->address);
+out:
+	return retval;
+}
+
+int acpi_processor_ffh_cstate_probe(unsigned int cpu,
+		struct acpi_processor_cx *cx, struct acpi_power_register *reg)
+{
+	struct cstate_entry *percpu_entry;
+	struct cpuinfo_x86 *c = &cpu_data(cpu);
+	long retval;
+
+	if (!cpu_cstate_entry || c->cpuid_level < CPUID_MWAIT_LEAF)
+		return -1;
+
+	if (reg->bit_offset != NATIVE_CSTATE_BEYOND_HALT)
+		return -1;
+
+	percpu_entry = per_cpu_ptr(cpu_cstate_entry, cpu);
+	percpu_entry->states[cx->index].eax = 0;
+	percpu_entry->states[cx->index].ecx = 0;
+
+	/* Make sure we are running on right CPU */
+
+	retval = call_on_cpu(cpu, acpi_processor_ffh_cstate_probe_cpu, cx,
+			     false);
+	if (retval == 0) {
+		/* Use the hint in CST */
+		percpu_entry->states[cx->index].eax = cx->address;
+		percpu_entry->states[cx->index].ecx = MWAIT_ECX_INTERRUPT_BREAK;
+	}
+
+	/*
+	 * For _CST FFH on Intel, if GAS.access_size bit 1 is cleared,
+	 * then we should skip checking BM_STS for this C-state.
+	 * ref: "Intel Processor Vendor-Specific ACPI Interface Specification"
+	 */
+	if ((c->x86_vendor == X86_VENDOR_INTEL) && !(reg->access_size & 0x2))
+		cx->bm_sts_skip = 1;
+
+	return retval;
+}
+EXPORT_SYMBOL_GPL(acpi_processor_ffh_cstate_probe);
+
+void __cpuidle acpi_processor_ffh_cstate_enter(struct acpi_processor_cx *cx)
+{
+	unsigned int cpu = smp_processor_id();
+	struct cstate_entry *percpu_entry;
+
+	percpu_entry = per_cpu_ptr(cpu_cstate_entry, cpu);
+	mwait_idle_with_hints(percpu_entry->states[cx->index].eax,
+	                      percpu_entry->states[cx->index].ecx);
+}
+EXPORT_SYMBOL_GPL(acpi_processor_ffh_cstate_enter);
+
+static int __init ffh_cstate_init(void)
+{
+	struct cpuinfo_x86 *c = &boot_cpu_data;
+
+	if (c->x86_vendor != X86_VENDOR_INTEL &&
+	    c->x86_vendor != X86_VENDOR_AMD &&
+	    c->x86_vendor != X86_VENDOR_HYGON)
+		return -1;
+
+	cpu_cstate_entry = alloc_percpu(struct cstate_entry);
+	return 0;
+}
+
+static void __exit ffh_cstate_exit(void)
+{
+	free_percpu(cpu_cstate_entry);
+	cpu_cstate_entry = NULL;
+}
+
+arch_initcall(ffh_cstate_init);
+__exitcall(ffh_cstate_exit);