/*
 * Copyright 2014, Michael Ellerman, IBM Corp.
 * Licensed under GPLv2.
 */

#define _GNU_SOURCE     /* For CPU_ZERO etc. */

#include <sched.h>
#include <sys/wait.h>
#include <setjmp.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>

#include "trace.h"
#include "reg.h"
#include "ebb.h"


void (*ebb_user_func)(void);

void ebb_hook(void)
{
        if (ebb_user_func)
                ebb_user_func();
}

struct ebb_state ebb_state;

u64 sample_period = 0x40000000ull;

void reset_ebb_with_clear_mask(unsigned long mmcr0_clear_mask)
{
        u64 val;

        /* 2) clear MMCR0[PMAO] - docs say BESCR[PMEO] should do this */
        /* 3) set MMCR0[PMAE]   - docs say BESCR[PME] should do this */
        val = mfspr(SPRN_MMCR0);
        mtspr(SPRN_MMCR0, (val & ~mmcr0_clear_mask) | MMCR0_PMAE);

        /* 4) clear BESCR[PMEO] */
        mtspr(SPRN_BESCRR, BESCR_PMEO);

        /* 5) set BESCR[PME] */
        mtspr(SPRN_BESCRS, BESCR_PME);

        /* 6) rfebb 1 - done in our caller */
}

void reset_ebb(void)
{
        reset_ebb_with_clear_mask(MMCR0_PMAO | MMCR0_FC);
}

/* Called outside of the EBB handler to check MMCR0 is sane */
int ebb_check_mmcr0(void)
{
        u64 val;

        val = mfspr(SPRN_MMCR0);
        if ((val & (MMCR0_FC | MMCR0_PMAO)) == MMCR0_FC) {
                /* It's OK if we see FC & PMAO, but not FC by itself */
                printf("Outside of loop, only FC set 0x%llx\n", val);
                return 1;
        }

        return 0;
}

bool ebb_check_count(int pmc, u64 sample_period, int fudge)
{
        u64 count, upper, lower;

        count = ebb_state.stats.pmc_count[PMC_INDEX(pmc)];

        lower = ebb_state.stats.ebb_count * (sample_period - fudge);

        if (count < lower) {
                printf("PMC%d count (0x%llx) below lower limit 0x%llx (-0x%llx)\n",
                        pmc, count, lower, lower - count);
                return false;
        }

        upper = ebb_state.stats.ebb_count * (sample_period + fudge);

        if (count > upper) {
                printf("PMC%d count (0x%llx) above upper limit 0x%llx (+0x%llx)\n",
                        pmc, count, upper, count - upper);
                return false;
        }

        printf("PMC%d count (0x%llx) is between 0x%llx and 0x%llx delta +0x%llx/-0x%llx\n",
                pmc, count, lower, upper, count - lower, upper - count);

        return true;
}

void standard_ebb_callee(void)
{
        int found, i;
        u64 val;

        val = mfspr(SPRN_BESCR);
        if (!(val & BESCR_PMEO)) {
                ebb_state.stats.spurious++;
                goto out;
        }

        ebb_state.stats.ebb_count++;
        trace_log_counter(ebb_state.trace, ebb_state.stats.ebb_count);

        val = mfspr(SPRN_MMCR0);
        trace_log_reg(ebb_state.trace, SPRN_MMCR0, val);

        found = 0;
        for (i = 1; i <= 6; i++) {
                if (ebb_state.pmc_enable[PMC_INDEX(i)])
                        found += count_pmc(i, sample_period);
        }

        if (!found)
                ebb_state.stats.no_overflow++;

out:
        reset_ebb();
}

extern void ebb_handler(void);

void setup_ebb_handler(void (*callee)(void))
{
        u64 entry;

#if defined(_CALL_ELF) && _CALL_ELF == 2
        entry = (u64)ebb_handler;
#else
        struct opd
        {
            u64 entry;
            u64 toc;
        } *opd;

        opd = (struct opd *)ebb_handler;
        entry = opd->entry;
#endif
        printf("EBB Handler is at %#llx\n", entry);

        ebb_user_func = callee;

        /* Ensure ebb_user_func is set before we set the handler */
        mb();
        mtspr(SPRN_EBBHR, entry);

        /* Make sure the handler is set before we return */
        mb();
}

void clear_ebb_stats(void)
{
        memset(&ebb_state.stats, 0, sizeof(ebb_state.stats));
}

void dump_summary_ebb_state(void)
{
        printf("ebb_state:\n"                   \
               "  ebb_count    = %d\n"          \
               "  spurious     = %d\n"          \
               "  negative     = %d\n"          \
               "  no_overflow  = %d\n"          \
               "  pmc[1] count = 0x%llx\n"      \
               "  pmc[2] count = 0x%llx\n"      \
               "  pmc[3] count = 0x%llx\n"      \
               "  pmc[4] count = 0x%llx\n"      \
               "  pmc[5] count = 0x%llx\n"      \
               "  pmc[6] count = 0x%llx\n",
                ebb_state.stats.ebb_count, ebb_state.stats.spurious,
                ebb_state.stats.negative, ebb_state.stats.no_overflow,
                ebb_state.stats.pmc_count[0], ebb_state.stats.pmc_count[1],
                ebb_state.stats.pmc_count[2], ebb_state.stats.pmc_count[3],
                ebb_state.stats.pmc_count[4], ebb_state.stats.pmc_count[5]);
}

static char *decode_mmcr0(u32 value)
{
        static char buf[16];

        buf[0] = '\0';

        if (value & (1 << 31))
                strcat(buf, "FC ");
        if (value & (1 << 26))
                strcat(buf, "PMAE ");
        if (value & (1 << 7))
                strcat(buf, "PMAO ");

        return buf;
}

static char *decode_bescr(u64 value)
{
        static char buf[16];

        buf[0] = '\0';

        if (value & (1ull << 63))
                strcat(buf, "GE ");
        if (value & (1ull << 32))
                strcat(buf, "PMAE ");
        if (value & 1)
                strcat(buf, "PMAO ");

        return buf;
}

void dump_ebb_hw_state(void)
{
        u64 bescr;
        u32 mmcr0;

        mmcr0 = mfspr(SPRN_MMCR0);
        bescr = mfspr(SPRN_BESCR);

        printf("HW state:\n"            \
               "MMCR0 0x%016x %s\n"     \
               "MMCR2 0x%016lx\n"       \
               "EBBHR 0x%016lx\n"       \
               "BESCR 0x%016llx %s\n"   \
               "PMC1  0x%016lx\n"       \
               "PMC2  0x%016lx\n"       \
               "PMC3  0x%016lx\n"       \
               "PMC4  0x%016lx\n"       \
               "PMC5  0x%016lx\n"       \
               "PMC6  0x%016lx\n"       \
               "SIAR  0x%016lx\n",
               mmcr0, decode_mmcr0(mmcr0), mfspr(SPRN_MMCR2),
               mfspr(SPRN_EBBHR), bescr, decode_bescr(bescr),
               mfspr(SPRN_PMC1), mfspr(SPRN_PMC2), mfspr(SPRN_PMC3),
               mfspr(SPRN_PMC4), mfspr(SPRN_PMC5), mfspr(SPRN_PMC6),
               mfspr(SPRN_SIAR));
}

void dump_ebb_state(void)
{
        dump_summary_ebb_state();

        dump_ebb_hw_state();

        trace_buffer_print(ebb_state.trace);
}

int count_pmc(int pmc, uint32_t sample_period)
{
        uint32_t start_value;
        u64 val;

        /* 0) Read PMC */
        start_value = pmc_sample_period(sample_period);

        val = read_pmc(pmc);
        if (val < start_value)
                ebb_state.stats.negative++;
        else
                ebb_state.stats.pmc_count[PMC_INDEX(pmc)] += val - start_value;

        trace_log_reg(ebb_state.trace, SPRN_PMC1 + pmc - 1, val);

        /* 1) Reset PMC */
        write_pmc(pmc, start_value);

        /* Report if we overflowed */
        return val >= COUNTER_OVERFLOW;
}

int ebb_event_enable(struct event *e)
{
        int rc;

        /* Ensure any SPR writes are ordered vs us */
        mb();

        rc = ioctl(e->fd, PERF_EVENT_IOC_ENABLE);
        if (rc)
                return rc;

        rc = event_read(e);

        /* Ditto */
        mb();

        return rc;
}

void ebb_freeze_pmcs(void)
{
        mtspr(SPRN_MMCR0, mfspr(SPRN_MMCR0) | MMCR0_FC);
        mb();
}

void ebb_unfreeze_pmcs(void)
{
        /* Unfreeze counters */
        mtspr(SPRN_MMCR0, mfspr(SPRN_MMCR0) & ~MMCR0_FC);
        mb();
}

void ebb_global_enable(void)
{
        /* Enable EBBs globally and PMU EBBs */
        mtspr(SPRN_BESCR, 0x8000000100000000ull);
        mb();
}

void ebb_global_disable(void)
{
        /* Disable EBBs & freeze counters, events are still scheduled */
        mtspr(SPRN_BESCRR, BESCR_PME);
        mb();
}

void event_ebb_init(struct event *e)
{
        e->attr.config |= (1ull << 63);
}

void event_bhrb_init(struct event *e, unsigned ifm)
{
        e->attr.config |= (1ull << 62) | ((u64)ifm << 60);
}

void event_leader_ebb_init(struct event *e)
{
        event_ebb_init(e);

        e->attr.exclusive = 1;
        e->attr.pinned = 1;
}

int ebb_child(union pipe read_pipe, union pipe write_pipe)
{
        struct event event;
        uint64_t val;

        FAIL_IF(wait_for_parent(read_pipe));

        event_init_named(&event, 0x1001e, "cycles");
        event_leader_ebb_init(&event);

        event.attr.exclude_kernel = 1;
        event.attr.exclude_hv = 1;
        event.attr.exclude_idle = 1;

        FAIL_IF(event_open(&event));

        ebb_enable_pmc_counting(1);
        setup_ebb_handler(standard_ebb_callee);
        ebb_global_enable();

        FAIL_IF(event_enable(&event));

        if (event_read(&event)) {
                /*
                 * Some tests expect to fail here, so don't report an error on
                 * this line, and return a distinguisable error code. Tell the
                 * parent an error happened.
                 */
                notify_parent_of_error(write_pipe);
                return 2;
        }

        mtspr(SPRN_PMC1, pmc_sample_period(sample_period));

        FAIL_IF(notify_parent(write_pipe));
        FAIL_IF(wait_for_parent(read_pipe));
        FAIL_IF(notify_parent(write_pipe));

        while (ebb_state.stats.ebb_count < 20) {
                FAIL_IF(core_busy_loop());

                /* To try and hit SIGILL case */
                val  = mfspr(SPRN_MMCRA);
                val |= mfspr(SPRN_MMCR2);
                val |= mfspr(SPRN_MMCR0);
        }

        ebb_global_disable();
        ebb_freeze_pmcs();

        count_pmc(1, sample_period);

        dump_ebb_state();

        event_close(&event);

        FAIL_IF(ebb_state.stats.ebb_count == 0);

        return 0;
}

static jmp_buf setjmp_env;

static void sigill_handler(int signal)
{
        printf("Took sigill\n");
        longjmp(setjmp_env, 1);
}

static struct sigaction sigill_action = {
        .sa_handler = sigill_handler,
};

int catch_sigill(void (*func)(void))
{
        if (sigaction(SIGILL, &sigill_action, NULL)) {
                perror("sigaction");
                return 1;
        }

        if (setjmp(setjmp_env) == 0) {
                func();
                return 1;
        }

        return 0;
}

void write_pmc1(void)
{
        mtspr(SPRN_PMC1, 0);
}

void write_pmc(int pmc, u64 value)
{
        switch (pmc) {
                case 1: mtspr(SPRN_PMC1, value); break;
                case 2: mtspr(SPRN_PMC2, value); break;
                case 3: mtspr(SPRN_PMC3, value); break;
                case 4: mtspr(SPRN_PMC4, value); break;
                case 5: mtspr(SPRN_PMC5, value); break;
                case 6: mtspr(SPRN_PMC6, value); break;
        }
}

u64 read_pmc(int pmc)
{
        switch (pmc) {
                case 1: return mfspr(SPRN_PMC1);
                case 2: return mfspr(SPRN_PMC2);
                case 3: return mfspr(SPRN_PMC3);
                case 4: return mfspr(SPRN_PMC4);
                case 5: return mfspr(SPRN_PMC5);
                case 6: return mfspr(SPRN_PMC6);
        }

        return 0;
}

static void term_handler(int signal)
{
        dump_summary_ebb_state();
        dump_ebb_hw_state();
        abort();
}

struct sigaction term_action = {
        .sa_handler = term_handler,
};

static void __attribute__((constructor)) ebb_init(void)
{
        clear_ebb_stats();

        if (sigaction(SIGTERM, &term_action, NULL))
                perror("sigaction");

        ebb_state.trace = trace_buffer_allocate(1 * 1024 * 1024);
}