// SPDX-License-Identifier: GPL-2.0
#include <linux/export.h>
#include <linux/preempt.h>
#include <linux/smp.h>
#include <linux/completion.h>
#include <asm/msr.h>

static void __rdmsr_on_cpu(void *info)
{
        struct msr_info *rv = info;
        struct msr *reg;

        if (rv->msrs)
                reg = this_cpu_ptr(rv->msrs);
        else
                reg = &rv->reg;

        rdmsr(rv->msr_no, reg->l, reg->h);
}

static void __wrmsr_on_cpu(void *info)
{
        struct msr_info *rv = info;
        struct msr *reg;

        if (rv->msrs)
                reg = this_cpu_ptr(rv->msrs);
        else
                reg = &rv->reg;

        wrmsr(rv->msr_no, reg->l, reg->h);
}

int rdmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
{
        int err;
        struct msr_info rv;

        memset(&rv, 0, sizeof(rv));

        rv.msr_no = msr_no;
        err = smp_call_function_single(cpu, __rdmsr_on_cpu, &rv, 1);
        *l = rv.reg.l;
        *h = rv.reg.h;

        return err;
}
EXPORT_SYMBOL(rdmsr_on_cpu);

int rdmsrq_on_cpu(unsigned int cpu, u32 msr_no, u64 *q)
{
        int err;
        struct msr_info rv;

        memset(&rv, 0, sizeof(rv));

        rv.msr_no = msr_no;
        err = smp_call_function_single(cpu, __rdmsr_on_cpu, &rv, 1);
        *q = rv.reg.q;

        return err;
}
EXPORT_SYMBOL(rdmsrq_on_cpu);

int wrmsr_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
{
        int err;
        struct msr_info rv;

        memset(&rv, 0, sizeof(rv));

        rv.msr_no = msr_no;
        rv.reg.l = l;
        rv.reg.h = h;
        err = smp_call_function_single(cpu, __wrmsr_on_cpu, &rv, 1);

        return err;
}
EXPORT_SYMBOL(wrmsr_on_cpu);

int wrmsrq_on_cpu(unsigned int cpu, u32 msr_no, u64 q)
{
        int err;
        struct msr_info rv;

        memset(&rv, 0, sizeof(rv));

        rv.msr_no = msr_no;
        rv.reg.q = q;

        err = smp_call_function_single(cpu, __wrmsr_on_cpu, &rv, 1);

        return err;
}
EXPORT_SYMBOL(wrmsrq_on_cpu);

static void __rwmsr_on_cpus(const struct cpumask *mask, u32 msr_no,
                            struct msr __percpu *msrs,
                            void (*msr_func) (void *info))
{
        struct msr_info rv;
        int this_cpu;

        memset(&rv, 0, sizeof(rv));

        rv.msrs   = msrs;
        rv.msr_no = msr_no;

        this_cpu = get_cpu();

        if (cpumask_test_cpu(this_cpu, mask))
                msr_func(&rv);

        smp_call_function_many(mask, msr_func, &rv, 1);
        put_cpu();
}

/* rdmsr on a bunch of CPUs
 *
 * @mask:       which CPUs
 * @msr_no:     which MSR
 * @msrs:       array of MSR values
 *
 */
void rdmsr_on_cpus(const struct cpumask *mask, u32 msr_no, struct msr __percpu *msrs)
{
        __rwmsr_on_cpus(mask, msr_no, msrs, __rdmsr_on_cpu);
}
EXPORT_SYMBOL(rdmsr_on_cpus);

/*
 * wrmsr on a bunch of CPUs
 *
 * @mask:       which CPUs
 * @msr_no:     which MSR
 * @msrs:       array of MSR values
 *
 */
void wrmsr_on_cpus(const struct cpumask *mask, u32 msr_no, struct msr __percpu *msrs)
{
        __rwmsr_on_cpus(mask, msr_no, msrs, __wrmsr_on_cpu);
}
EXPORT_SYMBOL(wrmsr_on_cpus);

struct msr_info_completion {
        struct msr_info         msr;
        struct completion       done;
};

/* These "safe" variants are slower and should be used when the target MSR
   may not actually exist. */
static void __rdmsr_safe_on_cpu(void *info)
{
        struct msr_info_completion *rv = info;

        rv->msr.err = rdmsr_safe(rv->msr.msr_no, &rv->msr.reg.l, &rv->msr.reg.h);
        complete(&rv->done);
}

static void __wrmsr_safe_on_cpu(void *info)
{
        struct msr_info *rv = info;

        rv->err = wrmsr_safe(rv->msr_no, rv->reg.l, rv->reg.h);
}

int rdmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 *l, u32 *h)
{
        struct msr_info_completion rv;
        call_single_data_t csd;
        int err;

        INIT_CSD(&csd, __rdmsr_safe_on_cpu, &rv);

        memset(&rv, 0, sizeof(rv));
        init_completion(&rv.done);
        rv.msr.msr_no = msr_no;

        err = smp_call_function_single_async(cpu, &csd);
        if (!err) {
                wait_for_completion(&rv.done);
                err = rv.msr.err;
        }
        *l = rv.msr.reg.l;
        *h = rv.msr.reg.h;

        return err;
}
EXPORT_SYMBOL(rdmsr_safe_on_cpu);

int wrmsr_safe_on_cpu(unsigned int cpu, u32 msr_no, u32 l, u32 h)
{
        int err;
        struct msr_info rv;

        memset(&rv, 0, sizeof(rv));

        rv.msr_no = msr_no;
        rv.reg.l = l;
        rv.reg.h = h;
        err = smp_call_function_single(cpu, __wrmsr_safe_on_cpu, &rv, 1);

        return err ? err : rv.err;
}
EXPORT_SYMBOL(wrmsr_safe_on_cpu);

int wrmsrq_safe_on_cpu(unsigned int cpu, u32 msr_no, u64 q)
{
        int err;
        struct msr_info rv;

        memset(&rv, 0, sizeof(rv));

        rv.msr_no = msr_no;
        rv.reg.q = q;

        err = smp_call_function_single(cpu, __wrmsr_safe_on_cpu, &rv, 1);

        return err ? err : rv.err;
}
EXPORT_SYMBOL(wrmsrq_safe_on_cpu);

int rdmsrq_safe_on_cpu(unsigned int cpu, u32 msr_no, u64 *q)
{
        u32 low, high;
        int err;

        err = rdmsr_safe_on_cpu(cpu, msr_no, &low, &high);
        *q = (u64)high << 32 | low;

        return err;
}
EXPORT_SYMBOL(rdmsrq_safe_on_cpu);

/*
 * These variants are significantly slower, but allows control over
 * the entire 32-bit GPR set.
 */
static void __rdmsr_safe_regs_on_cpu(void *info)
{
        struct msr_regs_info *rv = info;

        rv->err = rdmsr_safe_regs(rv->regs);
}

static void __wrmsr_safe_regs_on_cpu(void *info)
{
        struct msr_regs_info *rv = info;

        rv->err = wrmsr_safe_regs(rv->regs);
}

int rdmsr_safe_regs_on_cpu(unsigned int cpu, u32 regs[8])
{
        int err;
        struct msr_regs_info rv;

        rv.regs   = regs;
        rv.err    = -EIO;
        err = smp_call_function_single(cpu, __rdmsr_safe_regs_on_cpu, &rv, 1);

        return err ? err : rv.err;
}
EXPORT_SYMBOL(rdmsr_safe_regs_on_cpu);

int wrmsr_safe_regs_on_cpu(unsigned int cpu, u32 regs[8])
{
        int err;
        struct msr_regs_info rv;

        rv.regs = regs;
        rv.err  = -EIO;
        err = smp_call_function_single(cpu, __wrmsr_safe_regs_on_cpu, &rv, 1);

        return err ? err : rv.err;
}
EXPORT_SYMBOL(wrmsr_safe_regs_on_cpu);