1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2005 Intel Corporation 4 * Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> 5 * - Added _PDC for SMP C-states on Intel CPUs 6 */ 7 8 #include <linux/kernel.h> 9 #include <linux/export.h> 10 #include <linux/init.h> 11 #include <linux/acpi.h> 12 #include <linux/cpu.h> 13 #include <linux/sched.h> 14 15 #include <acpi/processor.h> 16 #include <asm/mwait.h> 17 #include <asm/special_insns.h> 18 19 /* 20 * Initialize bm_flags based on the CPU cache properties 21 * On SMP it depends on cache configuration 22 * - When cache is not shared among all CPUs, we flush cache 23 * before entering C3. 24 * - When cache is shared among all CPUs, we use bm_check 25 * mechanism as in UP case 26 * 27 * This routine is called only after all the CPUs are online 28 */ 29 void acpi_processor_power_init_bm_check(struct acpi_processor_flags *flags, 30 unsigned int cpu) 31 { 32 struct cpuinfo_x86 *c = &cpu_data(cpu); 33 34 flags->bm_check = 0; 35 if (num_online_cpus() == 1) 36 flags->bm_check = 1; 37 else if (c->x86_vendor == X86_VENDOR_INTEL) { 38 /* 39 * Today all MP CPUs that support C3 share cache. 40 * And caches should not be flushed by software while 41 * entering C3 type state. 42 */ 43 flags->bm_check = 1; 44 } 45 46 /* 47 * On all recent Intel platforms, ARB_DISABLE is a nop. 48 * So, set bm_control to zero to indicate that ARB_DISABLE 49 * is not required while entering C3 type state on 50 * P4, Core and beyond CPUs 51 */ 52 if (c->x86_vendor == X86_VENDOR_INTEL && 53 (c->x86 > 0xf || (c->x86 == 6 && c->x86_model >= 0x0f))) 54 flags->bm_control = 0; 55 /* 56 * For all recent Centaur CPUs, the ucode will make sure that each 57 * core can keep cache coherence with each other while entering C3 58 * type state. So, set bm_check to 1 to indicate that the kernel 59 * doesn't need to execute a cache flush operation (WBINVD) when 60 * entering C3 type state. 61 */ 62 if (c->x86_vendor == X86_VENDOR_CENTAUR) { 63 if (c->x86 > 6 || (c->x86 == 6 && c->x86_model == 0x0f && 64 c->x86_stepping >= 0x0e)) 65 flags->bm_check = 1; 66 } 67 68 if (c->x86_vendor == X86_VENDOR_ZHAOXIN) { 69 /* 70 * All Zhaoxin CPUs that support C3 share cache. 71 * And caches should not be flushed by software while 72 * entering C3 type state. 73 */ 74 flags->bm_check = 1; 75 /* 76 * On all recent Zhaoxin platforms, ARB_DISABLE is a nop. 77 * So, set bm_control to zero to indicate that ARB_DISABLE 78 * is not required while entering C3 type state. 79 */ 80 flags->bm_control = 0; 81 } 82 } 83 EXPORT_SYMBOL(acpi_processor_power_init_bm_check); 84 85 /* The code below handles cstate entry with monitor-mwait pair on Intel*/ 86 87 struct cstate_entry { 88 struct { 89 unsigned int eax; 90 unsigned int ecx; 91 } states[ACPI_PROCESSOR_MAX_POWER]; 92 }; 93 static struct cstate_entry __percpu *cpu_cstate_entry; /* per CPU ptr */ 94 95 static short mwait_supported[ACPI_PROCESSOR_MAX_POWER]; 96 97 #define NATIVE_CSTATE_BEYOND_HALT (2) 98 99 static long acpi_processor_ffh_cstate_probe_cpu(void *_cx) 100 { 101 struct acpi_processor_cx *cx = _cx; 102 long retval; 103 unsigned int eax, ebx, ecx, edx; 104 unsigned int edx_part; 105 unsigned int cstate_type; /* C-state type and not ACPI C-state type */ 106 unsigned int num_cstate_subtype; 107 108 cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx); 109 110 /* Check whether this particular cx_type (in CST) is supported or not */ 111 cstate_type = ((cx->address >> MWAIT_SUBSTATE_SIZE) & 112 MWAIT_CSTATE_MASK) + 1; 113 edx_part = edx >> (cstate_type * MWAIT_SUBSTATE_SIZE); 114 num_cstate_subtype = edx_part & MWAIT_SUBSTATE_MASK; 115 116 retval = 0; 117 /* If the HW does not support any sub-states in this C-state */ 118 if (num_cstate_subtype == 0) { 119 pr_warn(FW_BUG "ACPI MWAIT C-state 0x%x not supported by HW (0x%x)\n", 120 cx->address, edx_part); 121 retval = -1; 122 goto out; 123 } 124 125 /* mwait ecx extensions INTERRUPT_BREAK should be supported for C2/C3 */ 126 if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) || 127 !(ecx & CPUID5_ECX_INTERRUPT_BREAK)) { 128 retval = -1; 129 goto out; 130 } 131 132 if (!mwait_supported[cstate_type]) { 133 mwait_supported[cstate_type] = 1; 134 printk(KERN_DEBUG 135 "Monitor-Mwait will be used to enter C-%d state\n", 136 cx->type); 137 } 138 snprintf(cx->desc, 139 ACPI_CX_DESC_LEN, "ACPI FFH MWAIT 0x%x", 140 cx->address); 141 out: 142 return retval; 143 } 144 145 int acpi_processor_ffh_cstate_probe(unsigned int cpu, 146 struct acpi_processor_cx *cx, struct acpi_power_register *reg) 147 { 148 struct cstate_entry *percpu_entry; 149 struct cpuinfo_x86 *c = &cpu_data(cpu); 150 long retval; 151 152 if (!cpu_cstate_entry || c->cpuid_level < CPUID_MWAIT_LEAF) 153 return -1; 154 155 if (reg->bit_offset != NATIVE_CSTATE_BEYOND_HALT) 156 return -1; 157 158 percpu_entry = per_cpu_ptr(cpu_cstate_entry, cpu); 159 percpu_entry->states[cx->index].eax = 0; 160 percpu_entry->states[cx->index].ecx = 0; 161 162 /* Make sure we are running on right CPU */ 163 164 retval = call_on_cpu(cpu, acpi_processor_ffh_cstate_probe_cpu, cx, 165 false); 166 if (retval == 0) { 167 /* Use the hint in CST */ 168 percpu_entry->states[cx->index].eax = cx->address; 169 percpu_entry->states[cx->index].ecx = MWAIT_ECX_INTERRUPT_BREAK; 170 } 171 172 /* 173 * For _CST FFH on Intel, if GAS.access_size bit 1 is cleared, 174 * then we should skip checking BM_STS for this C-state. 175 * ref: "Intel Processor Vendor-Specific ACPI Interface Specification" 176 */ 177 if ((c->x86_vendor == X86_VENDOR_INTEL) && !(reg->access_size & 0x2)) 178 cx->bm_sts_skip = 1; 179 180 return retval; 181 } 182 EXPORT_SYMBOL_GPL(acpi_processor_ffh_cstate_probe); 183 184 void __cpuidle acpi_processor_ffh_cstate_enter(struct acpi_processor_cx *cx) 185 { 186 unsigned int cpu = smp_processor_id(); 187 struct cstate_entry *percpu_entry; 188 189 percpu_entry = per_cpu_ptr(cpu_cstate_entry, cpu); 190 mwait_idle_with_hints(percpu_entry->states[cx->index].eax, 191 percpu_entry->states[cx->index].ecx); 192 } 193 EXPORT_SYMBOL_GPL(acpi_processor_ffh_cstate_enter); 194 195 static int __init ffh_cstate_init(void) 196 { 197 struct cpuinfo_x86 *c = &boot_cpu_data; 198 199 if (c->x86_vendor != X86_VENDOR_INTEL && 200 c->x86_vendor != X86_VENDOR_AMD) 201 return -1; 202 203 cpu_cstate_entry = alloc_percpu(struct cstate_entry); 204 return 0; 205 } 206 207 static void __exit ffh_cstate_exit(void) 208 { 209 free_percpu(cpu_cstate_entry); 210 cpu_cstate_entry = NULL; 211 } 212 213 arch_initcall(ffh_cstate_init); 214 __exitcall(ffh_cstate_exit); 215