// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright (C) 2004 Anton Blanchard <anton@au.ibm.com>, IBM
 * Added mmcra[slot] support:
 * Copyright (C) 2006-2007 Will Schmidt <willschm@us.ibm.com>, IBM
 */

#include <linux/oprofile.h>
#include <linux/smp.h>
#include <asm/firmware.h>
#include <asm/ptrace.h>
#include <asm/processor.h>
#include <asm/cputable.h>
#include <asm/rtas.h>
#include <asm/oprofile_impl.h>
#include <asm/reg.h>

#define dbg(args...)
#define OPROFILE_PM_PMCSEL_MSK      0xffULL
#define OPROFILE_PM_UNIT_SHIFT      60
#define OPROFILE_PM_UNIT_MSK        0xfULL
#define OPROFILE_MAX_PMC_NUM        3
#define OPROFILE_PMSEL_FIELD_WIDTH  8
#define OPROFILE_UNIT_FIELD_WIDTH   4
#define MMCRA_SIAR_VALID_MASK       0x10000000ULL

static unsigned long reset_value[OP_MAX_COUNTER];

static int oprofile_running;
static int use_slot_nums;

/* mmcr values are set in power4_reg_setup, used in power4_cpu_setup */
static u32 mmcr0_val;
static u64 mmcr1_val;
static u64 mmcra_val;
static u32 cntr_marked_events;

static int power7_marked_instr_event(u64 mmcr1)
{
        u64 psel, unit;
        int pmc, cntr_marked_events = 0;

        /* Given the MMCR1 value, look at the field for each counter to
         * determine if it is a marked event.  Code based on the function
         * power7_marked_instr_event() in file arch/powerpc/perf/power7-pmu.c.
         */
        for (pmc = 0; pmc < 4; pmc++) {
                psel = mmcr1 & (OPROFILE_PM_PMCSEL_MSK
                                << (OPROFILE_MAX_PMC_NUM - pmc)
                                * OPROFILE_PMSEL_FIELD_WIDTH);
                psel = (psel >> ((OPROFILE_MAX_PMC_NUM - pmc)
                                 * OPROFILE_PMSEL_FIELD_WIDTH)) & ~1ULL;
                unit = mmcr1 & (OPROFILE_PM_UNIT_MSK
                                << (OPROFILE_PM_UNIT_SHIFT
                                    - (pmc * OPROFILE_PMSEL_FIELD_WIDTH )));
                unit = unit >> (OPROFILE_PM_UNIT_SHIFT
                                - (pmc * OPROFILE_PMSEL_FIELD_WIDTH));

                switch (psel >> 4) {
                case 2:
                        cntr_marked_events |= (pmc == 1 || pmc == 3) << pmc;
                        break;
                case 3:
                        if (psel == 0x3c) {
                                cntr_marked_events |= (pmc == 0) << pmc;
                                break;
                        }

                        if (psel == 0x3e) {
                                cntr_marked_events |= (pmc != 1) << pmc;
                                break;
                        }

                        cntr_marked_events |= 1 << pmc;
                        break;
                case 4:
                case 5:
                        cntr_marked_events |= (unit == 0xd) << pmc;
                        break;
                case 6:
                        if (psel == 0x64)
                                cntr_marked_events |= (pmc >= 2) << pmc;
                        break;
                case 8:
                        cntr_marked_events |= (unit == 0xd) << pmc;
                        break;
                }
        }
        return cntr_marked_events;
}

static int power4_reg_setup(struct op_counter_config *ctr,
                             struct op_system_config *sys,
                             int num_ctrs)
{
        int i;

        /*
         * The performance counter event settings are given in the mmcr0,
         * mmcr1 and mmcra values passed from the user in the
         * op_system_config structure (sys variable).
         */
        mmcr0_val = sys->mmcr0;
        mmcr1_val = sys->mmcr1;
        mmcra_val = sys->mmcra;

        /* Power 7+ and newer architectures:
         * Determine which counter events in the group (the group of events is
         * specified by the bit settings in the MMCR1 register) are marked
         * events for use in the interrupt handler.  Do the calculation once
         * before OProfile starts.  Information is used in the interrupt
         * handler.  Starting with Power 7+ we only record the sample for
         * marked events if the SIAR valid bit is set.  For non marked events
         * the sample is always recorded.
         */
        if (pvr_version_is(PVR_POWER7p))
                cntr_marked_events = power7_marked_instr_event(mmcr1_val);
        else
                cntr_marked_events = 0; /* For older processors, set the bit map
                                         * to zero so the sample will always be
                                         * be recorded.
                                         */

        for (i = 0; i < cur_cpu_spec->num_pmcs; ++i)
                reset_value[i] = 0x80000000UL - ctr[i].count;

        /* setup user and kernel profiling */
        if (sys->enable_kernel)
                mmcr0_val &= ~MMCR0_KERNEL_DISABLE;
        else
                mmcr0_val |= MMCR0_KERNEL_DISABLE;

        if (sys->enable_user)
                mmcr0_val &= ~MMCR0_PROBLEM_DISABLE;
        else
                mmcr0_val |= MMCR0_PROBLEM_DISABLE;

        if (pvr_version_is(PVR_POWER4) || pvr_version_is(PVR_POWER4p) ||
            pvr_version_is(PVR_970) || pvr_version_is(PVR_970FX) ||
            pvr_version_is(PVR_970MP) || pvr_version_is(PVR_970GX) ||
            pvr_version_is(PVR_POWER5) || pvr_version_is(PVR_POWER5p))
                use_slot_nums = 1;

        return 0;
}

extern void ppc_enable_pmcs(void);

/*
 * Older CPUs require the MMCRA sample bit to be always set, but newer 
 * CPUs only want it set for some groups. Eventually we will remove all
 * knowledge of this bit in the kernel, oprofile userspace should be
 * setting it when required.
 *
 * In order to keep current installations working we force the bit for
 * those older CPUs. Once everyone has updated their oprofile userspace we
 * can remove this hack.
 */
static inline int mmcra_must_set_sample(void)
{
        if (pvr_version_is(PVR_POWER4) || pvr_version_is(PVR_POWER4p) ||
            pvr_version_is(PVR_970) || pvr_version_is(PVR_970FX) ||
            pvr_version_is(PVR_970MP) || pvr_version_is(PVR_970GX))
                return 1;

        return 0;
}

static int power4_cpu_setup(struct op_counter_config *ctr)
{
        unsigned int mmcr0 = mmcr0_val;
        unsigned long mmcra = mmcra_val;

        ppc_enable_pmcs();

        /* set the freeze bit */
        mmcr0 |= MMCR0_FC;
        mtspr(SPRN_MMCR0, mmcr0);

        mmcr0 |= MMCR0_FCM1|MMCR0_PMXE|MMCR0_FCECE;
        mmcr0 |= MMCR0_PMC1CE|MMCR0_PMCjCE;
        mtspr(SPRN_MMCR0, mmcr0);

        mtspr(SPRN_MMCR1, mmcr1_val);

        if (mmcra_must_set_sample())
                mmcra |= MMCRA_SAMPLE_ENABLE;
        mtspr(SPRN_MMCRA, mmcra);

        dbg("setup on cpu %d, mmcr0 %lx\n", smp_processor_id(),
            mfspr(SPRN_MMCR0));
        dbg("setup on cpu %d, mmcr1 %lx\n", smp_processor_id(),
            mfspr(SPRN_MMCR1));
        dbg("setup on cpu %d, mmcra %lx\n", smp_processor_id(),
            mfspr(SPRN_MMCRA));

        return 0;
}

static int power4_start(struct op_counter_config *ctr)
{
        int i;
        unsigned int mmcr0;

        /* set the PMM bit (see comment below) */
        mtmsr(mfmsr() | MSR_PMM);

        for (i = 0; i < cur_cpu_spec->num_pmcs; ++i) {
                if (ctr[i].enabled) {
                        classic_ctr_write(i, reset_value[i]);
                } else {
                        classic_ctr_write(i, 0);
                }
        }

        mmcr0 = mfspr(SPRN_MMCR0);

        /*
         * We must clear the PMAO bit on some (GQ) chips. Just do it
         * all the time
         */
        mmcr0 &= ~MMCR0_PMAO;

        /*
         * now clear the freeze bit, counting will not start until we
         * rfid from this excetion, because only at that point will
         * the PMM bit be cleared
         */
        mmcr0 &= ~MMCR0_FC;
        mtspr(SPRN_MMCR0, mmcr0);

        oprofile_running = 1;

        dbg("start on cpu %d, mmcr0 %x\n", smp_processor_id(), mmcr0);
        return 0;
}

static void power4_stop(void)
{
        unsigned int mmcr0;

        /* freeze counters */
        mmcr0 = mfspr(SPRN_MMCR0);
        mmcr0 |= MMCR0_FC;
        mtspr(SPRN_MMCR0, mmcr0);

        oprofile_running = 0;

        dbg("stop on cpu %d, mmcr0 %x\n", smp_processor_id(), mmcr0);

        mb();
}

/* Fake functions used by canonicalize_pc */
static void __used hypervisor_bucket(void)
{
}

static void __used rtas_bucket(void)
{
}

static void __used kernel_unknown_bucket(void)
{
}

/*
 * On GQ and newer the MMCRA stores the HV and PR bits at the time
 * the SIAR was sampled. We use that to work out if the SIAR was sampled in
 * the hypervisor, our exception vectors or RTAS.
 * If the MMCRA_SAMPLE_ENABLE bit is set, we can use the MMCRA[slot] bits
 * to more accurately identify the address of the sampled instruction. The
 * mmcra[slot] bits represent the slot number of a sampled instruction
 * within an instruction group.  The slot will contain a value between 1
 * and 5 if MMCRA_SAMPLE_ENABLE is set, otherwise 0.
 */
static unsigned long get_pc(struct pt_regs *regs)
{
        unsigned long pc = mfspr(SPRN_SIAR);
        unsigned long mmcra;
        unsigned long slot;

        /* Can't do much about it */
        if (!cur_cpu_spec->oprofile_mmcra_sihv)
                return pc;

        mmcra = mfspr(SPRN_MMCRA);

        if (use_slot_nums && (mmcra & MMCRA_SAMPLE_ENABLE)) {
                slot = ((mmcra & MMCRA_SLOT) >> MMCRA_SLOT_SHIFT);
                if (slot > 1)
                        pc += 4 * (slot - 1);
        }

        /* Were we in the hypervisor? */
        if (firmware_has_feature(FW_FEATURE_LPAR) &&
            (mmcra & cur_cpu_spec->oprofile_mmcra_sihv))
                /* function descriptor madness */
                return *((unsigned long *)hypervisor_bucket);

        /* We were in userspace, nothing to do */
        if (mmcra & cur_cpu_spec->oprofile_mmcra_sipr)
                return pc;

#ifdef CONFIG_PPC_RTAS
        /* Were we in RTAS? */
        if (pc >= rtas.base && pc < (rtas.base + rtas.size))
                /* function descriptor madness */
                return *((unsigned long *)rtas_bucket);
#endif

        /* Were we in our exception vectors or SLB real mode miss handler? */
        if (pc < 0x1000000UL)
                return (unsigned long)__va(pc);

        /* Not sure where we were */
        if (!is_kernel_addr(pc))
                /* function descriptor madness */
                return *((unsigned long *)kernel_unknown_bucket);

        return pc;
}

static int get_kernel(unsigned long pc, unsigned long mmcra)
{
        int is_kernel;

        if (!cur_cpu_spec->oprofile_mmcra_sihv) {
                is_kernel = is_kernel_addr(pc);
        } else {
                is_kernel = ((mmcra & cur_cpu_spec->oprofile_mmcra_sipr) == 0);
        }

        return is_kernel;
}

static bool pmc_overflow(unsigned long val)
{
        if ((int)val < 0)
                return true;

        /*
         * Events on POWER7 can roll back if a speculative event doesn't
         * eventually complete. Unfortunately in some rare cases they will
         * raise a performance monitor exception. We need to catch this to
         * ensure we reset the PMC. In all cases the PMC will be 256 or less
         * cycles from overflow.
         *
         * We only do this if the first pass fails to find any overflowing
         * PMCs because a user might set a period of less than 256 and we
         * don't want to mistakenly reset them.
         */
        if (pvr_version_is(PVR_POWER7) && ((0x80000000 - val) <= 256))
                return true;

        return false;
}

static void power4_handle_interrupt(struct pt_regs *regs,
                                    struct op_counter_config *ctr)
{
        unsigned long pc;
        int is_kernel;
        int val;
        int i;
        unsigned int mmcr0;
        unsigned long mmcra;
        bool siar_valid = false;

        mmcra = mfspr(SPRN_MMCRA);

        pc = get_pc(regs);
        is_kernel = get_kernel(pc, mmcra);

        /* set the PMM bit (see comment below) */
        mtmsr(mfmsr() | MSR_PMM);

        /* Check that the SIAR  valid bit in MMCRA is set to 1. */
        if ((mmcra & MMCRA_SIAR_VALID_MASK) == MMCRA_SIAR_VALID_MASK)
                siar_valid = true;

        for (i = 0; i < cur_cpu_spec->num_pmcs; ++i) {
                val = classic_ctr_read(i);
                if (pmc_overflow(val)) {
                        if (oprofile_running && ctr[i].enabled) {
                                /* Power 7+ and newer architectures:
                                 * If the event is a marked event, then only
                                 * save the sample if the SIAR valid bit is
                                 * set.  If the event is not marked, then
                                 * always save the sample.
                                 * Note, the Sample enable bit in the MMCRA
                                 * register must be set to 1 if the group
                                 * contains a marked event.
                                 */
                                if ((siar_valid &&
                                     (cntr_marked_events & (1 << i)))
                                    || !(cntr_marked_events & (1 << i)))
                                        oprofile_add_ext_sample(pc, regs, i,
                                                                is_kernel);

                                classic_ctr_write(i, reset_value[i]);
                        } else {
                                classic_ctr_write(i, 0);
                        }
                }
        }

        mmcr0 = mfspr(SPRN_MMCR0);

        /* reset the perfmon trigger */
        mmcr0 |= MMCR0_PMXE;

        /*
         * We must clear the PMAO bit on some (GQ) chips. Just do it
         * all the time
         */
        mmcr0 &= ~MMCR0_PMAO;

        /* Clear the appropriate bits in the MMCRA */
        mmcra &= ~cur_cpu_spec->oprofile_mmcra_clear;
        mtspr(SPRN_MMCRA, mmcra);

        /*
         * now clear the freeze bit, counting will not start until we
         * rfid from this exception, because only at that point will
         * the PMM bit be cleared
         */
        mmcr0 &= ~MMCR0_FC;
        mtspr(SPRN_MMCR0, mmcr0);
}

struct op_powerpc_model op_model_power4 = {
        .reg_setup              = power4_reg_setup,
        .cpu_setup              = power4_cpu_setup,
        .start                  = power4_start,
        .stop                   = power4_stop,
        .handle_interrupt       = power4_handle_interrupt,
};