1 /**
2 * @file arch/alpha/oprofile/op_model_ev4.c
3 *
4 * @remark Copyright 2002 OProfile authors
5 * @remark Read the file COPYING
6 *
7 * @author Richard Henderson <rth@twiddle.net>
8 */
9
10 #include <linux/oprofile.h>
11 #include <linux/init.h>
12 #include <linux/smp.h>
13 #include <asm/ptrace.h>
14 #include <asm/system.h>
15
16 #include "op_impl.h"
17
18
19 /* Compute all of the registers in preparation for enabling profiling. */
20
21 static void
ev4_reg_setup(struct op_register_config * reg,struct op_counter_config * ctr,struct op_system_config * sys)22 ev4_reg_setup(struct op_register_config *reg,
23 struct op_counter_config *ctr,
24 struct op_system_config *sys)
25 {
26 unsigned long ctl = 0, count, hilo;
27
28 /* Select desired events. We've mapped the event numbers
29 such that they fit directly into the event selection fields.
30
31 Note that there is no "off" setting. In both cases we select
32 the EXTERNAL event source, hoping that it'll be the lowest
33 frequency, and set the frequency counter to LOW. The interrupts
34 for these "disabled" counter overflows are ignored by the
35 interrupt handler.
36
37 This is most irritating, because the hardware *can* enable and
38 disable the interrupts for these counters independently, but the
39 wrperfmon interface doesn't allow it. */
40
41 ctl |= (ctr[0].enabled ? ctr[0].event << 8 : 14 << 8);
42 ctl |= (ctr[1].enabled ? (ctr[1].event - 16) << 32 : 7ul << 32);
43
44 /* EV4 can not read or write its counter registers. The only
45 thing one can do at all is see if you overflow and get an
46 interrupt. We can set the width of the counters, to some
47 extent. Take the interrupt count selected by the user,
48 map it onto one of the possible values, and write it back. */
49
50 count = ctr[0].count;
51 if (count <= 4096)
52 count = 4096, hilo = 1;
53 else
54 count = 65536, hilo = 0;
55 ctr[0].count = count;
56 ctl |= (ctr[0].enabled && hilo) << 3;
57
58 count = ctr[1].count;
59 if (count <= 256)
60 count = 256, hilo = 1;
61 else
62 count = 4096, hilo = 0;
63 ctr[1].count = count;
64 ctl |= (ctr[1].enabled && hilo);
65
66 reg->mux_select = ctl;
67
68 /* Select performance monitoring options. */
69 /* ??? Need to come up with some mechanism to trace only
70 selected processes. EV4 does not have a mechanism to
71 select kernel or user mode only. For now, enable always. */
72 reg->proc_mode = 0;
73
74 /* Frequency is folded into mux_select for EV4. */
75 reg->freq = 0;
76
77 /* See above regarding no writes. */
78 reg->reset_values = 0;
79 reg->need_reset = 0;
80
81 }
82
83 /* Program all of the registers in preparation for enabling profiling. */
84
85 static void
ev4_cpu_setup(void * x)86 ev4_cpu_setup(void *x)
87 {
88 struct op_register_config *reg = x;
89
90 wrperfmon(2, reg->mux_select);
91 wrperfmon(3, reg->proc_mode);
92 }
93
94 static void
ev4_handle_interrupt(unsigned long which,struct pt_regs * regs,struct op_counter_config * ctr)95 ev4_handle_interrupt(unsigned long which, struct pt_regs *regs,
96 struct op_counter_config *ctr)
97 {
98 /* EV4 can't properly disable counters individually.
99 Discard "disabled" events now. */
100 if (!ctr[which].enabled)
101 return;
102
103 /* Record the sample. */
104 oprofile_add_sample(regs, which);
105 }
106
107
108 struct op_axp_model op_model_ev4 = {
109 .reg_setup = ev4_reg_setup,
110 .cpu_setup = ev4_cpu_setup,
111 .reset_ctr = NULL,
112 .handle_interrupt = ev4_handle_interrupt,
113 .cpu_type = "alpha/ev4",
114 .num_counters = 2,
115 .can_set_proc_mode = 0,
116 };
117