cregit-Linux how code gets into the kernel

Release 4.14 arch/alpha/oprofile/op_model_ev4.c

/**
 * @file arch/alpha/oprofile/op_model_ev4.c
 *
 * @remark Copyright 2002 OProfile authors
 * @remark Read the file COPYING
 *
 * @author Richard Henderson <rth@twiddle.net>
 */

#include <linux/oprofile.h>
#include <linux/smp.h>
#include <asm/ptrace.h>

#include "op_impl.h"


/* Compute all of the registers in preparation for enabling profiling.  */


static void ev4_reg_setup(struct op_register_config *reg, struct op_counter_config *ctr, struct op_system_config *sys) { unsigned long ctl = 0, count, hilo; /* Select desired events. We've mapped the event numbers such that they fit directly into the event selection fields. Note that there is no "off" setting. In both cases we select the EXTERNAL event source, hoping that it'll be the lowest frequency, and set the frequency counter to LOW. The interrupts for these "disabled" counter overflows are ignored by the interrupt handler. This is most irritating, because the hardware *can* enable and disable the interrupts for these counters independently, but the wrperfmon interface doesn't allow it. */ ctl |= (ctr[0].enabled ? ctr[0].event << 8 : 14 << 8); ctl |= (ctr[1].enabled ? (ctr[1].event - 16) << 32 : 7ul << 32); /* EV4 can not read or write its counter registers. The only thing one can do at all is see if you overflow and get an interrupt. We can set the width of the counters, to some extent. Take the interrupt count selected by the user, map it onto one of the possible values, and write it back. */ count = ctr[0].count; if (count <= 4096) count = 4096, hilo = 1; else count = 65536, hilo = 0; ctr[0].count = count; ctl |= (ctr[0].enabled && hilo) << 3; count = ctr[1].count; if (count <= 256) count = 256, hilo = 1; else count = 4096, hilo = 0; ctr[1].count = count; ctl |= (ctr[1].enabled && hilo); reg->mux_select = ctl; /* Select performance monitoring options. */ /* ??? Need to come up with some mechanism to trace only selected processes. EV4 does not have a mechanism to select kernel or user mode only. For now, enable always. */ reg->proc_mode = 0; /* Frequency is folded into mux_select for EV4. */ reg->freq = 0; /* See above regarding no writes. */ reg->reset_values = 0; reg->need_reset = 0; }

Contributors

PersonTokensPropCommitsCommitProp
Richard Henderson22899.56%150.00%
John Levon10.44%150.00%
Total229100.00%2100.00%

/* Program all of the registers in preparation for enabling profiling. */
static void ev4_cpu_setup(void *x) { struct op_register_config *reg = x; wrperfmon(2, reg->mux_select); wrperfmon(3, reg->proc_mode); }

Contributors

PersonTokensPropCommitsCommitProp
Richard Henderson35100.00%1100.00%
Total35100.00%1100.00%


static void ev4_handle_interrupt(unsigned long which, struct pt_regs *regs, struct op_counter_config *ctr) { /* EV4 can't properly disable counters individually. Discard "disabled" events now. */ if (!ctr[which].enabled) return; /* Record the sample. */ oprofile_add_sample(regs, which); }

Contributors

PersonTokensPropCommitsCommitProp
Richard Henderson40100.00%2100.00%
Total40100.00%2100.00%

struct op_axp_model op_model_ev4 = { .reg_setup = ev4_reg_setup, .cpu_setup = ev4_cpu_setup, .reset_ctr = NULL, .handle_interrupt = ev4_handle_interrupt, .cpu_type = "alpha/ev4", .num_counters = 2, .can_set_proc_mode = 0, };

Overall Contributors

PersonTokensPropCommitsCommitProp
Richard Henderson35999.72%480.00%
John Levon10.28%120.00%
Total360100.00%5100.00%
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