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 <asm/irq.h>
  20 #include <asm/cpu_mf.h>
  21 #include <asm/lowcore.h>
  22 #include <asm/processor.h>
  23
  24 const char *perf_pmu_name(void)
  25 {
  26         if (cpum_cf_avail() || cpum_sf_avail())
  27                 return "CPU-measurement facilities (CPUMF)";
  28         return "pmu";
  29 }
  30 EXPORT_SYMBOL(perf_pmu_name);
  31
  32 int perf_num_counters(void)
  33 {
  34         int num = 0;
  35
  36         if (cpum_cf_avail())
  37                 num += PERF_CPUM_CF_MAX_CTR;
  38
  39         return num;
  40 }
  41 EXPORT_SYMBOL(perf_num_counters);
  42
  43 static struct kvm_s390_sie_block *sie_block(struct pt_regs *regs)
  44 {
  45         struct stack_frame *stack = (struct stack_frame *) regs->gprs[15];
  46
  47         if (!stack)
  48                 return NULL;
  49
  50         return (struct kvm_s390_sie_block *) stack->empty1[0];
  51 }
  52
  53 static bool is_in_guest(struct pt_regs *regs)
  54 {
  55         if (user_mode(regs))
  56                 return false;
  57 #if defined(CONFIG_KVM) || defined(CONFIG_KVM_MODULE)
  58         return instruction_pointer(regs) == (unsigned long) &sie_exit;
  59 #else
  60         return false;
  61 #endif
  62 }
  63
  64 static unsigned long guest_is_user_mode(struct pt_regs *regs)
  65 {
  66         return sie_block(regs)->gpsw.mask & PSW_MASK_PSTATE;
  67 }
  68
  69 static unsigned long instruction_pointer_guest(struct pt_regs *regs)
  70 {
  71         return sie_block(regs)->gpsw.addr & PSW_ADDR_INSN;
  72 }
  73
  74 unsigned long perf_instruction_pointer(struct pt_regs *regs)
  75 {
  76         return is_in_guest(regs) ? instruction_pointer_guest(regs)
  77                                  : instruction_pointer(regs);
  78 }
  79
  80 static unsigned long perf_misc_guest_flags(struct pt_regs *regs)
  81 {
  82         return guest_is_user_mode(regs) ? PERF_RECORD_MISC_GUEST_USER
  83                                         : PERF_RECORD_MISC_GUEST_KERNEL;
  84 }
  85
  86 unsigned long perf_misc_flags(struct pt_regs *regs)
  87 {
  88         if (is_in_guest(regs))
  89                 return perf_misc_guest_flags(regs);
  90
  91         return user_mode(regs) ? PERF_RECORD_MISC_USER
  92                                : PERF_RECORD_MISC_KERNEL;
  93 }
  94
  95 void perf_event_print_debug(void)
  96 {
  97         struct cpumf_ctr_info cf_info;
  98         unsigned long flags;
  99         int cpu;
 100
 101         if (!cpum_cf_avail())
 102                 return;
 103
 104         local_irq_save(flags);
 105
 106         cpu = smp_processor_id();
 107         memset(&cf_info, 0, sizeof(cf_info));
 108         if (!qctri(&cf_info))
 109                 pr_info("CPU[%i] CPUM_CF: ver=%u.%u A=%04x E=%04x C=%04x\n",
 110                         cpu, cf_info.cfvn, cf_info.csvn,
 111                         cf_info.auth_ctl, cf_info.enable_ctl, cf_info.act_ctl);
 112
 113         local_irq_restore(flags);
 114 }
 115
 116 /* See also arch/s390/kernel/traps.c */
 117 static unsigned long __store_trace(struct perf_callchain_entry *entry,
 118                                    unsigned long sp,
 119                                    unsigned long low, unsigned long high)
 120 {
 121         struct stack_frame *sf;
 122         struct pt_regs *regs;
 123
 124         while (1) {
 125                 sp = sp & PSW_ADDR_INSN;
 126                 if (sp < low || sp > high - sizeof(*sf))
 127                         return sp;
 128                 sf = (struct stack_frame *) sp;
 129                 perf_callchain_store(entry, sf->gprs[8] & PSW_ADDR_INSN);
 130                 /* Follow the backchain. */
 131                 while (1) {
 132                         low = sp;
 133                         sp = sf->back_chain & PSW_ADDR_INSN;
 134                         if (!sp)
 135                                 break;
 136                         if (sp <= low || sp > high - sizeof(*sf))
 137                                 return sp;
 138                         sf = (struct stack_frame *) sp;
 139                         perf_callchain_store(entry,
 140                                              sf->gprs[8] & PSW_ADDR_INSN);
 141                 }
 142                 /* Zero backchain detected, check for interrupt frame. */
 143                 sp = (unsigned long) (sf + 1);
 144                 if (sp <= low || sp > high - sizeof(*regs))
 145                         return sp;
 146                 regs = (struct pt_regs *) sp;
 147                 perf_callchain_store(entry, sf->gprs[8] & PSW_ADDR_INSN);
 148                 low = sp;
 149                 sp = regs->gprs[15];
 150         }
 151 }
 152
 153 void perf_callchain_kernel(struct perf_callchain_entry *entry,
 154                            struct pt_regs *regs)
 155 {
 156         unsigned long head;
 157         struct stack_frame *head_sf;
 158
 159         if (user_mode(regs))
 160                 return;
 161
 162         head = regs->gprs[15];
 163         head_sf = (struct stack_frame *) head;
 164
 165         if (!head_sf || !head_sf->back_chain)
 166                 return;
 167
 168         head = head_sf->back_chain;
 169         head = __store_trace(entry, head, S390_lowcore.async_stack - ASYNC_SIZE,
 170                              S390_lowcore.async_stack);
 171
 172         __store_trace(entry, head, S390_lowcore.thread_info,
 173                       S390_lowcore.thread_info + THREAD_SIZE);
 174 }