/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright 2018 Joyent, Inc.
 */

/*
 * HAT interfaces used by the kernel debugger to interact with the VM system.
 * These interfaces are invoked when the world is stopped.  As such, no blocking
 * operations may be performed.
 */

#include <sys/cpuvar.h>
#include <sys/kdi_impl.h>
#include <sys/errno.h>
#include <sys/systm.h>
#include <sys/sysmacros.h>
#include <sys/mman.h>
#include <sys/bootconf.h>
#include <sys/cmn_err.h>
#include <vm/seg_kmem.h>
#include <vm/hat_i86.h>
#if defined(__xpv)
#include <sys/hypervisor.h>
#endif
#include <sys/bootinfo.h>
#include <vm/kboot_mmu.h>
#include <sys/machsystm.h>

/*
 * The debugger needs direct access to the PTE of one page table entry
 * in order to implement vtop and physical read/writes
 */
static uintptr_t hat_kdi_page = 0;      /* vaddr for phsical page accesses */
static uint_t use_kbm = 1;
uint_t hat_kdi_use_pae;                 /* if 0, use x86pte32_t for pte type */

#if !defined(__xpv)
static x86pte_t *hat_kdi_pte = NULL;    /* vaddr of pte for hat_kdi_page */
#endif

/*
 * Get the address for remapping physical pages during boot
 */
void
hat_boot_kdi_init(void)
{
        hat_kdi_page = (uintptr_t)kbm_push(0);  /* first call gets address... */
}

/*
 * Switch to using a page in the kernel's va range for physical memory access.
 * We need to allocate a virtual page, then permanently map in the page that
 * contains the PTE to it.
 */
void
hat_kdi_init(void)
{
        /*LINTED:set but not used in function*/
        htable_t *ht __unused;

        /*
         * Get an kernel page VA to use for phys mem access. Then make sure
         * the VA has a page table.
         */
        hat_kdi_use_pae = mmu.pae_hat;
        hat_kdi_page = (uintptr_t)vmem_alloc(heap_arena, PAGESIZE, VM_SLEEP);
        ht = htable_create(kas.a_hat, hat_kdi_page, 0, NULL);
        use_kbm = 0;

#ifndef __xpv
        /*
         * Get an address at which to put the pagetable and devload it.
         */
        hat_kdi_pte = vmem_xalloc(heap_arena, MMU_PAGESIZE, MMU_PAGESIZE, 0,
            0, NULL, NULL, VM_SLEEP);
        hat_devload(kas.a_hat, (caddr_t)hat_kdi_pte, MMU_PAGESIZE, ht->ht_pfn,
            PROT_READ | PROT_WRITE | HAT_NOSYNC | HAT_UNORDERED_OK,
            HAT_LOAD | HAT_LOAD_NOCONSIST);
        hat_kdi_pte =
            PT_INDEX_PTR(hat_kdi_pte, htable_va2entry(hat_kdi_page, ht));

        HTABLE_INC(ht->ht_valid_cnt);
        htable_release(ht);
#endif
}

#ifdef __xpv

/*
 * translate machine address to physical address
 */
static uint64_t
kdi_ptom(uint64_t pa)
{
        extern pfn_t *mfn_list;
        ulong_t mfn = mfn_list[mmu_btop(pa)];

        return (pfn_to_pa(mfn) | (pa & MMU_PAGEOFFSET));
}

/*
 * This is like mfn_to_pfn(), but we can't use ontrap() from kmdb.
 * Instead we let the fault happen and kmdb deals with it.
 */
static uint64_t
kdi_mtop(uint64_t ma)
{
        pfn_t pfn;
        mfn_t mfn = ma >> MMU_PAGESHIFT;

        if (HYPERVISOR_memory_op(XENMEM_maximum_ram_page, NULL) < mfn)
                return (ma | PFN_IS_FOREIGN_MFN);

        pfn = mfn_to_pfn_mapping[mfn];
        if (pfn >= mfn_count || pfn_to_mfn(pfn) != mfn)
                return (ma | PFN_IS_FOREIGN_MFN);
        return (pfn_to_pa(pfn) | (ma & MMU_PAGEOFFSET));
}

#else
#define kdi_mtop(m)     (m)
#define kdi_ptom(p)     (p)
#endif

/*ARGSUSED*/
int
kdi_vtop(uintptr_t va, uint64_t *pap)
{
        uintptr_t vaddr = va;
        size_t  len;
        pfn_t   pfn;
        uint_t  prot;
        int     level;
        x86pte_t pte;
        int     index;

        /*
         * if the mmu struct isn't relevant yet, we need to probe
         * the boot loader's pagetables.
         */
        if (!khat_running) {
                if (kbm_probe(&vaddr, &len, &pfn, &prot) == 0)
                        return (ENOENT);
                if (vaddr > va)
                        return (ENOENT);
                if (vaddr < va)
                        pfn += mmu_btop(va - vaddr);
                *pap = pfn_to_pa(pfn) + (vaddr & MMU_PAGEOFFSET);
                return (0);
        }

        /*
         * We can't go through normal hat routines, so we'll use
         * kdi_pread() to walk the page tables
         */
#if defined(__xpv)
        *pap = pfn_to_pa(CPU->cpu_current_hat->hat_htable->ht_pfn);
#else
        *pap = getcr3_pa();
#endif
        for (level = mmu.max_level; ; --level) {
                index = (va >> LEVEL_SHIFT(level)) & (mmu.ptes_per_table - 1);
                *pap += index << mmu.pte_size_shift;
                pte = 0;
                if (kdi_pread((caddr_t)&pte, mmu.pte_size, *pap, &len) != 0)
                        return (ENOENT);
                if (pte == 0)
                        return (ENOENT);
                if (level > 0 && level <= mmu.max_page_level &&
                    (pte & PT_PAGESIZE)) {
                        *pap = kdi_mtop(pte & PT_PADDR_LGPG);
                        break;
                } else {
                        *pap = kdi_mtop(pte & PT_PADDR);
                        if (level == 0)
                                break;
                }
        }
        *pap += va & LEVEL_OFFSET(level);
        return (0);
}

static int
kdi_prw(caddr_t buf, size_t nbytes, uint64_t pa, size_t *ncopiedp, int doread)
{
        size_t  ncopied = 0;
        off_t   pgoff;
        size_t  sz;
        caddr_t va;
        caddr_t from;
        caddr_t to;
        x86pte_t pte;

        /*
         * if this is called before any initialization - fail
         */
        if (hat_kdi_page == 0)
                return (EAGAIN);

        while (nbytes > 0) {
                /*
                 * figure out the addresses and construct a minimal PTE
                 */
                pgoff = pa & MMU_PAGEOFFSET;
                sz = MIN(nbytes, MMU_PAGESIZE - pgoff);
                va = (caddr_t)hat_kdi_page + pgoff;
                pte = kdi_ptom(mmu_ptob(mmu_btop(pa))) | PT_VALID;
                if (doread) {
                        from = va;
                        to = buf;
                } else {
                        PTE_SET(pte, PT_WRITABLE);
                        from = buf;
                        to = va;
                }

                /*
                 * map the physical page
                 */
                if (use_kbm)
                        (void) kbm_push(pa);
#if defined(__xpv)
                else
                        (void) HYPERVISOR_update_va_mapping(
                            (uintptr_t)va, pte, UVMF_INVLPG);
#else
                else if (hat_kdi_use_pae)
                        *hat_kdi_pte = pte;
                else
                        *(x86pte32_t *)hat_kdi_pte = pte;
                mmu_flush_tlb_kpage(hat_kdi_page);
#endif

                bcopy(from, to, sz);

                /*
                 * erase the mapping
                 */
                if (use_kbm)
                        kbm_pop();
#if defined(__xpv)
                else
                        (void) HYPERVISOR_update_va_mapping(
                            (uintptr_t)va, 0, UVMF_INVLPG);
#else
                else if (hat_kdi_use_pae)
                        *hat_kdi_pte = 0;
                else
                        *(x86pte32_t *)hat_kdi_pte = 0;
                mmu_flush_tlb_kpage(hat_kdi_page);
#endif

                buf += sz;
                pa += sz;
                nbytes -= sz;
                ncopied += sz;
        }

        if (ncopied == 0)
                return (ENOENT);

        *ncopiedp = ncopied;
        return (0);
}

int
kdi_pread(caddr_t buf, size_t nbytes, uint64_t addr, size_t *ncopiedp)
{
        return (kdi_prw(buf, nbytes, addr, ncopiedp, 1));
}

int
kdi_pwrite(caddr_t buf, size_t nbytes, uint64_t addr, size_t *ncopiedp)
{
        return (kdi_prw(buf, nbytes, addr, ncopiedp, 0));
}

#if !defined(__xpv)
/*
 * This gets used for flushing the TLB on all the slaves just prior to doing a
 * kdi_prw().  It's unclear why this was originally done, since kdi_prw() itself
 * will flush any lingering hat_kdi_page mappings, but let's presume it was a
 * good idea.
 */
void
kdi_flush_caches(void)
{
        mmu_flush_tlb(FLUSH_TLB_ALL, NULL);
}
#endif

/*
 * Return the number of bytes, relative to the beginning of a given range, that
 * are non-toxic (can be read from and written to with relative impunity).
 */
/*ARGSUSED*/
size_t
kdi_range_is_nontoxic(uintptr_t va, size_t sz, int write)
{
        extern uintptr_t toxic_addr;
        extern size_t   toxic_size;

        /*
         * Check 64 bit toxic range.
         */
        if (toxic_addr != 0 &&
            va + sz >= toxic_addr &&
            va < toxic_addr + toxic_size)
                return (va < toxic_addr ? toxic_addr - va : 0);

        /*
         * avoid any Virtual Address hole
         */
        if (va + sz >= hole_start && va < hole_end)
                return (va < hole_start ? hole_start - va : 0);

        return (sz);
}