arch/s390/kernel/perf_event.c

   1 /*
   2  * Performance event support for s390x
   3  *
   4  *  Copyright IBM Corp. 2012
   5  *  Author(s): Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License (version 2 only)
   9  * as published by the Free Software Foundation.
  10  */
  11 #define KMSG_COMPONENT  "perf"
  12 #define pr_fmt(fmt)     KMSG_COMPONENT ": " fmt
  13
  14 #include <linux/kernel.h>
  15 #include <linux/perf_event.h>
  16 #include <linux/kvm_host.h>
  17 #include <linux/percpu.h>
  18 #include <linux/export.h>
  19 #include <linux/spinlock.h>
  20 #include <linux/sysfs.h>
  21 #include <asm/irq.h>
  22 #include <asm/cpu_mf.h>
  23 #include <asm/lowcore.h>
  24 #include <asm/processor.h>
  25
  26 const char *perf_pmu_name(void)
  27 {
  28         if (cpum_cf_avail() || cpum_sf_avail())
  29                 return "CPU-measurement facilities (CPUMF)";
  30         return "pmu";
  31 }
  32 EXPORT_SYMBOL(perf_pmu_name);
  33
  34 int perf_num_counters(void)
  35 {
  36         int num = 0;
  37
  38         if (cpum_cf_avail())
  39                 num += PERF_CPUM_CF_MAX_CTR;
  40         if (cpum_sf_avail())
  41                 num += PERF_CPUM_SF_MAX_CTR;
  42
  43         return num;
  44 }
  45 EXPORT_SYMBOL(perf_num_counters);
  46
  47 static struct kvm_s390_sie_block *sie_block(struct pt_regs *regs)
  48 {
  49         struct stack_frame *stack = (struct stack_frame *) regs->gprs[15];
  50
  51         if (!stack)
  52                 return NULL;
  53
  54         return (struct kvm_s390_sie_block *) stack->empty1[0];
  55 }
  56
  57 static bool is_in_guest(struct pt_regs *regs)
  58 {
  59         if (user_mode(regs))
  60                 return false;
  61 #if defined(CONFIG_KVM) || defined(CONFIG_KVM_MODULE)
  62         return instruction_pointer(regs) == (unsigned long) &sie_exit;
  63 #else
  64         return false;
  65 #endif
  66 }
  67
  68 static unsigned long guest_is_user_mode(struct pt_regs *regs)
  69 {
  70         return sie_block(regs)->gpsw.mask & PSW_MASK_PSTATE;
  71 }
  72
  73 static unsigned long instruction_pointer_guest(struct pt_regs *regs)
  74 {
  75         return sie_block(regs)->gpsw.addr & PSW_ADDR_INSN;
  76 }
  77
  78 unsigned long perf_instruction_pointer(struct pt_regs *regs)
  79 {
  80         return is_in_guest(regs) ? instruction_pointer_guest(regs)
  81                                  : instruction_pointer(regs);
  82 }
  83
  84 static unsigned long perf_misc_guest_flags(struct pt_regs *regs)
  85 {
  86         return guest_is_user_mode(regs) ? PERF_RECORD_MISC_GUEST_USER
  87                                         : PERF_RECORD_MISC_GUEST_KERNEL;
  88 }
  89
  90 unsigned long perf_misc_flags(struct pt_regs *regs)
  91 {
  92         if (is_in_guest(regs))
  93                 return perf_misc_guest_flags(regs);
  94
  95         return user_mode(regs) ? PERF_RECORD_MISC_USER
  96                                : PERF_RECORD_MISC_KERNEL;
  97 }
  98
  99 void print_debug_cf(void)
 100 {
 101         struct cpumf_ctr_info cf_info;
 102         int cpu = smp_processor_id();
 103
 104         memset(&cf_info, 0, sizeof(cf_info));
 105         if (!qctri(&cf_info))
 106                 pr_info("CPU[%i] CPUM_CF: ver=%u.%u A=%04x E=%04x C=%04x\n",
 107                         cpu, cf_info.cfvn, cf_info.csvn,
 108                         cf_info.auth_ctl, cf_info.enable_ctl, cf_info.act_ctl);
 109 }
 110
 111 static void print_debug_sf(void)
 112 {
 113         struct hws_qsi_info_block si;
 114         int cpu = smp_processor_id();
 115
 116         memset(&si, 0, sizeof(si));
 117         if (qsi(&si)) {
 118                 pr_err("CPU[%i]: CPM_SF: qsi failed\n");
 119                 return;
 120         }
 121
 122         pr_info("CPU[%i]: CPM_SF: as=%i es=%i cs=%i bsdes=%i dsdes=%i"
 123                 " min=%i max=%i cpu_speed=%i tear=%p dear=%p\n",
 124                 cpu, si.as, si.es, si.cs, si.bsdes, si.dsdes,
 125                 si.min_sampl_rate, si.max_sampl_rate, si.cpu_speed,
 126                 si.tear, si.dear);
 127 }
 128
 129 void perf_event_print_debug(void)
 130 {
 131         unsigned long flags;
 132
 133         local_irq_save(flags);
 134         if (cpum_cf_avail())
 135                 print_debug_cf();
 136         if (cpum_sf_avail())
 137                 print_debug_sf();
 138         local_irq_restore(flags);
 139 }
 140
 141 /* See also arch/s390/kernel/traps.c */
 142 static unsigned long __store_trace(struct perf_callchain_entry *entry,
 143                                    unsigned long sp,
 144                                    unsigned long low, unsigned long high)
 145 {
 146         struct stack_frame *sf;
 147         struct pt_regs *regs;
 148
 149         while (1) {
 150                 sp = sp & PSW_ADDR_INSN;
 151                 if (sp < low || sp > high - sizeof(*sf))
 152                         return sp;
 153                 sf = (struct stack_frame *) sp;
 154                 perf_callchain_store(entry, sf->gprs[8] & PSW_ADDR_INSN);
 155                 /* Follow the backchain. */
 156                 while (1) {
 157                         low = sp;
 158                         sp = sf->back_chain & PSW_ADDR_INSN;
 159                         if (!sp)
 160                                 break;
 161                         if (sp <= low || sp > high - sizeof(*sf))
 162                                 return sp;
 163                         sf = (struct stack_frame *) sp;
 164                         perf_callchain_store(entry,
 165                                              sf->gprs[8] & PSW_ADDR_INSN);
 166                 }
 167                 /* Zero backchain detected, check for interrupt frame. */
 168                 sp = (unsigned long) (sf + 1);
 169                 if (sp <= low || sp > high - sizeof(*regs))
 170                         return sp;
 171                 regs = (struct pt_regs *) sp;
 172                 perf_callchain_store(entry, sf->gprs[8] & PSW_ADDR_INSN);
 173                 low = sp;
 174                 sp = regs->gprs[15];
 175         }
 176 }
 177
 178 void perf_callchain_kernel(struct perf_callchain_entry *entry,
 179                            struct pt_regs *regs)
 180 {
 181         unsigned long head;
 182         struct stack_frame *head_sf;
 183
 184         if (user_mode(regs))
 185                 return;
 186
 187         head = regs->gprs[15];
 188         head_sf = (struct stack_frame *) head;
 189
 190         if (!head_sf || !head_sf->back_chain)
 191                 return;
 192
 193         head = head_sf->back_chain;
 194         head = __store_trace(entry, head, S390_lowcore.async_stack - ASYNC_SIZE,
 195                              S390_lowcore.async_stack);
 196
 197         __store_trace(entry, head, S390_lowcore.thread_info,
 198                       S390_lowcore.thread_info + THREAD_SIZE);
 199 }
 200
 201 /* Perf defintions for PMU event attributes in sysfs */
 202 ssize_t cpumf_events_sysfs_show(struct device *dev,
 203                                 struct device_attribute *attr, char *page)
 204 {
 205         struct perf_pmu_events_attr *pmu_attr;
 206
 207         pmu_attr = container_of(attr, struct perf_pmu_events_attr, attr);
 208         return sprintf(page, "event=0x%04llx,name=%s\n",
 209                        pmu_attr->id, attr->attr.name);
 210 }