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         unsigned long ip = instruction_pointer(regs);
  56
  57         if (user_mode(regs))
  58                 return false;
  59
  60         return ip == (unsigned long) &sie_exit;
  61 }
  62
  63 static unsigned long guest_is_user_mode(struct pt_regs *regs)
  64 {
  65         return sie_block(regs)->gpsw.mask & PSW_MASK_PSTATE;
  66 }
  67
  68 static unsigned long instruction_pointer_guest(struct pt_regs *regs)
  69 {
  70         return sie_block(regs)->gpsw.addr & PSW_ADDR_INSN;
  71 }
  72
  73 unsigned long perf_instruction_pointer(struct pt_regs *regs)
  74 {
  75         return is_in_guest(regs) ? instruction_pointer_guest(regs)
  76                                  : instruction_pointer(regs);
  77 }
  78
  79 static unsigned long perf_misc_guest_flags(struct pt_regs *regs)
  80 {
  81         return guest_is_user_mode(regs) ? PERF_RECORD_MISC_GUEST_USER
  82                                         : PERF_RECORD_MISC_GUEST_KERNEL;
  83 }
  84
  85 unsigned long perf_misc_flags(struct pt_regs *regs)
  86 {
  87         if (is_in_guest(regs))
  88                 return perf_misc_guest_flags(regs);
  89
  90         return user_mode(regs) ? PERF_RECORD_MISC_USER
  91                                : PERF_RECORD_MISC_KERNEL;
  92 }
  93
  94 void perf_event_print_debug(void)
  95 {
  96         struct cpumf_ctr_info cf_info;
  97         unsigned long flags;
  98         int cpu;
  99
 100         if (!cpum_cf_avail())
 101                 return;
 102
 103         local_irq_save(flags);
 104
 105         cpu = smp_processor_id();
 106         memset(&cf_info, 0, sizeof(cf_info));
 107         if (!qctri(&cf_info)) {
 108                 pr_info("CPU[%i] CPUM_CF: ver=%u.%u A=%04x E=%04x C=%04x\n",
 109                         cpu, cf_info.cfvn, cf_info.csvn,
 110                         cf_info.auth_ctl, cf_info.enable_ctl, cf_info.act_ctl);
 111                 print_hex_dump_bytes("CPUMF Query: ", DUMP_PREFIX_OFFSET,
 112                                      &cf_info, sizeof(cf_info));
 113         }
 114
 115         local_irq_restore(flags);
 116 }
 117
 118 /* See also arch/s390/kernel/traps.c */
 119 static unsigned long __store_trace(struct perf_callchain_entry *entry,
 120                                    unsigned long sp,
 121                                    unsigned long low, unsigned long high)
 122 {
 123         struct stack_frame *sf;
 124         struct pt_regs *regs;
 125
 126         while (1) {
 127                 sp = sp & PSW_ADDR_INSN;
 128                 if (sp < low || sp > high - sizeof(*sf))
 129                         return sp;
 130                 sf = (struct stack_frame *) sp;
 131                 perf_callchain_store(entry, sf->gprs[8] & PSW_ADDR_INSN);
 132                 /* Follow the backchain. */
 133                 while (1) {
 134                         low = sp;
 135                         sp = sf->back_chain & PSW_ADDR_INSN;
 136                         if (!sp)
 137                                 break;
 138                         if (sp <= low || sp > high - sizeof(*sf))
 139                                 return sp;
 140                         sf = (struct stack_frame *) sp;
 141                         perf_callchain_store(entry,
 142                                              sf->gprs[8] & PSW_ADDR_INSN);
 143                 }
 144                 /* Zero backchain detected, check for interrupt frame. */
 145                 sp = (unsigned long) (sf + 1);
 146                 if (sp <= low || sp > high - sizeof(*regs))
 147                         return sp;
 148                 regs = (struct pt_regs *) sp;
 149                 perf_callchain_store(entry, sf->gprs[8] & PSW_ADDR_INSN);
 150                 low = sp;
 151                 sp = regs->gprs[15];
 152         }
 153 }
 154
 155 void perf_callchain_kernel(struct perf_callchain_entry *entry,
 156                            struct pt_regs *regs)
 157 {
 158         unsigned long head;
 159         struct stack_frame *head_sf;
 160
 161         if (user_mode(regs))
 162                 return;
 163
 164         head = regs->gprs[15];
 165         head_sf = (struct stack_frame *) head;
 166
 167         if (!head_sf || !head_sf->back_chain)
 168                 return;
 169
 170         head = head_sf->back_chain;
 171         head = __store_trace(entry, head, S390_lowcore.async_stack - ASYNC_SIZE,
 172                              S390_lowcore.async_stack);
 173
 174         __store_trace(entry, head, S390_lowcore.thread_info,
 175                       S390_lowcore.thread_info + THREAD_SIZE);
 176 }