/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(c) 2010-2014 Intel Corporation
 */
#include <inttypes.h>
#include <stdint.h>
#include <stddef.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/queue.h>

#include <rte_memory.h>
#include <rte_eal.h>
#include <rte_launch.h>
#include <rte_per_lcore.h>
#include <rte_lcore.h>
#include <rte_debug.h>
#include <rte_common.h>
#include <rte_spinlock.h>

#include "eal_private.h"
#include "eal_internal_cfg.h"
#include "eal_memalloc.h"
#include "malloc_elem.h"
#include "malloc_heap.h"

/*
 * If debugging is enabled, freed memory is set to poison value
 * to catch buggy programs. Otherwise, freed memory is set to zero
 * to avoid having to zero in zmalloc
 */
#ifdef RTE_MALLOC_DEBUG
#define MALLOC_POISON          0x6b
#else
#define MALLOC_POISON          0
#endif

size_t
malloc_elem_find_max_iova_contig(struct malloc_elem *elem, size_t align)
{
        void *cur_page, *contig_seg_start, *page_end, *cur_seg_end;
        void *data_start, *data_end;
        rte_iova_t expected_iova;
        struct rte_memseg *ms;
        size_t page_sz, cur, max;
        const struct internal_config *internal_conf =
                eal_get_internal_configuration();

        page_sz = (size_t)elem->msl->page_sz;
        data_start = RTE_PTR_ADD(elem, MALLOC_ELEM_HEADER_LEN);
        data_end = RTE_PTR_ADD(elem, elem->size - MALLOC_ELEM_TRAILER_LEN);
        /* segment must start after header and with specified alignment */
        contig_seg_start = RTE_PTR_ALIGN_CEIL(data_start, align);

        /* return if aligned address is already out of malloc element */
        if (contig_seg_start > data_end)
                return 0;

        /* if we're in IOVA as VA mode, or if we're in legacy mode with
         * hugepages, all elements are IOVA-contiguous. however, we can only
         * make these assumptions about internal memory - externally allocated
         * segments have to be checked.
         */
        if (!elem->msl->external &&
                        (rte_eal_iova_mode() == RTE_IOVA_VA ||
                                (internal_conf->legacy_mem &&
                                        rte_eal_has_hugepages())))
                return RTE_PTR_DIFF(data_end, contig_seg_start);

        cur_page = RTE_PTR_ALIGN_FLOOR(contig_seg_start, page_sz);
        ms = rte_mem_virt2memseg(cur_page, elem->msl);

        /* do first iteration outside the loop */
        page_end = RTE_PTR_ADD(cur_page, page_sz);
        cur_seg_end = RTE_MIN(page_end, data_end);
        cur = RTE_PTR_DIFF(cur_seg_end, contig_seg_start) -
                        MALLOC_ELEM_TRAILER_LEN;
        max = cur;
        expected_iova = ms->iova + page_sz;
        /* memsegs are contiguous in memory */
        ms++;

        cur_page = RTE_PTR_ADD(cur_page, page_sz);

        while (cur_page < data_end) {
                page_end = RTE_PTR_ADD(cur_page, page_sz);
                cur_seg_end = RTE_MIN(page_end, data_end);

                /* reset start of contiguous segment if unexpected iova */
                if (ms->iova != expected_iova) {
                        /* next contiguous segment must start at specified
                         * alignment.
                         */
                        contig_seg_start = RTE_PTR_ALIGN(cur_page, align);
                        /* new segment start may be on a different page, so find
                         * the page and skip to next iteration to make sure
                         * we're not blowing past data end.
                         */
                        ms = rte_mem_virt2memseg(contig_seg_start, elem->msl);
                        cur_page = ms->addr;
                        /* don't trigger another recalculation */
                        expected_iova = ms->iova;
                        continue;
                }
                /* cur_seg_end ends on a page boundary or on data end. if we're
                 * looking at data end, then malloc trailer is already included
                 * in the calculations. if we're looking at page end, then we
                 * know there's more data past this page and thus there's space
                 * for malloc element trailer, so don't count it here.
                 */
                cur = RTE_PTR_DIFF(cur_seg_end, contig_seg_start);
                /* update max if cur value is bigger */
                if (cur > max)
                        max = cur;

                /* move to next page */
                cur_page = page_end;
                expected_iova = ms->iova + page_sz;
                /* memsegs are contiguous in memory */
                ms++;
        }

        return max;
}

/*
 * Initialize a general malloc_elem header structure
 */
void
malloc_elem_init(struct malloc_elem *elem, struct malloc_heap *heap,
                struct rte_memseg_list *msl, size_t size,
                struct malloc_elem *orig_elem, size_t orig_size)
{
        elem->heap = heap;
        elem->msl = msl;
        elem->prev = NULL;
        elem->next = NULL;
        memset(&elem->free_list, 0, sizeof(elem->free_list));
        elem->state = ELEM_FREE;
        elem->size = size;
        elem->pad = 0;
        elem->orig_elem = orig_elem;
        elem->orig_size = orig_size;
        set_header(elem);
        set_trailer(elem);
}

void
malloc_elem_insert(struct malloc_elem *elem)
{
        struct malloc_elem *prev_elem, *next_elem;
        struct malloc_heap *heap = elem->heap;

        /* first and last elements must be both NULL or both non-NULL */
        if ((heap->first == NULL) != (heap->last == NULL)) {
                RTE_LOG(ERR, EAL, "Heap is probably corrupt\n");
                return;
        }

        if (heap->first == NULL && heap->last == NULL) {
                /* if empty heap */
                heap->first = elem;
                heap->last = elem;
                prev_elem = NULL;
                next_elem = NULL;
        } else if (elem < heap->first) {
                /* if lower than start */
                prev_elem = NULL;
                next_elem = heap->first;
                heap->first = elem;
        } else if (elem > heap->last) {
                /* if higher than end */
                prev_elem = heap->last;
                next_elem = NULL;
                heap->last = elem;
        } else {
                /* the new memory is somewhere between start and end */
                uint64_t dist_from_start, dist_from_end;

                dist_from_end = RTE_PTR_DIFF(heap->last, elem);
                dist_from_start = RTE_PTR_DIFF(elem, heap->first);

                /* check which is closer, and find closest list entries */
                if (dist_from_start < dist_from_end) {
                        prev_elem = heap->first;
                        while (prev_elem->next < elem)
                                prev_elem = prev_elem->next;
                        next_elem = prev_elem->next;
                } else {
                        next_elem = heap->last;
                        while (next_elem->prev > elem)
                                next_elem = next_elem->prev;
                        prev_elem = next_elem->prev;
                }
        }

        /* insert new element */
        elem->prev = prev_elem;
        elem->next = next_elem;
        if (prev_elem)
                prev_elem->next = elem;
        if (next_elem)
                next_elem->prev = elem;
}

/*
 * Attempt to find enough physically contiguous memory in this block to store
 * our data. Assume that element has at least enough space to fit in the data,
 * so we just check the page addresses.
 */
static bool
elem_check_phys_contig(const struct rte_memseg_list *msl,
                void *start, size_t size)
{
        return eal_memalloc_is_contig(msl, start, size);
}

/*
 * calculate the starting point of where data of the requested size
 * and alignment would fit in the current element. If the data doesn't
 * fit, return NULL.
 */
static void *
elem_start_pt(struct malloc_elem *elem, size_t size, unsigned align,
                size_t bound, bool contig)
{
        size_t elem_size = elem->size;

        /*
         * we're allocating from the end, so adjust the size of element by
         * alignment size.
         */
        while (elem_size >= size) {
                const size_t bmask = ~(bound - 1);
                uintptr_t end_pt = (uintptr_t)elem +
                                elem_size - MALLOC_ELEM_TRAILER_LEN;
                uintptr_t new_data_start = RTE_ALIGN_FLOOR((end_pt - size),
                                align);
                uintptr_t new_elem_start;

                /* check boundary */
                if ((new_data_start & bmask) != ((end_pt - 1) & bmask)) {
                        end_pt = RTE_ALIGN_FLOOR(end_pt, bound);
                        new_data_start = RTE_ALIGN_FLOOR((end_pt - size),
                                        align);
                        end_pt = new_data_start + size;

                        if (((end_pt - 1) & bmask) != (new_data_start & bmask))
                                return NULL;
                }

                new_elem_start = new_data_start - MALLOC_ELEM_HEADER_LEN;

                /* if the new start point is before the exist start,
                 * it won't fit
                 */
                if (new_elem_start < (uintptr_t)elem)
                        return NULL;

                if (contig) {
                        size_t new_data_size = end_pt - new_data_start;

                        /*
                         * if physical contiguousness was requested and we
                         * couldn't fit all data into one physically contiguous
                         * block, try again with lower addresses.
                         */
                        if (!elem_check_phys_contig(elem->msl,
                                        (void *)new_data_start,
                                        new_data_size)) {
                                elem_size -= align;
                                continue;
                        }
                }
                return (void *)new_elem_start;
        }
        return NULL;
}

/*
 * use elem_start_pt to determine if we get meet the size and
 * alignment request from the current element
 */
int
malloc_elem_can_hold(struct malloc_elem *elem, size_t size,     unsigned align,
                size_t bound, bool contig)
{
        return elem_start_pt(elem, size, align, bound, contig) != NULL;
}

/*
 * split an existing element into two smaller elements at the given
 * split_pt parameter.
 */
static void
split_elem(struct malloc_elem *elem, struct malloc_elem *split_pt)
{
        struct malloc_elem *next_elem = elem->next;
        const size_t old_elem_size = (uintptr_t)split_pt - (uintptr_t)elem;
        const size_t new_elem_size = elem->size - old_elem_size;

        malloc_elem_init(split_pt, elem->heap, elem->msl, new_elem_size,
                         elem->orig_elem, elem->orig_size);
        split_pt->prev = elem;
        split_pt->next = next_elem;
        if (next_elem)
                next_elem->prev = split_pt;
        else
                elem->heap->last = split_pt;
        elem->next = split_pt;
        elem->size = old_elem_size;
        set_trailer(elem);
        if (elem->pad) {
                /* Update inner padding inner element size. */
                elem = RTE_PTR_ADD(elem, elem->pad);
                elem->size = old_elem_size - elem->pad;
        }
}

/*
 * our malloc heap is a doubly linked list, so doubly remove our element.
 */
static void __rte_unused
remove_elem(struct malloc_elem *elem)
{
        struct malloc_elem *next, *prev;
        next = elem->next;
        prev = elem->prev;

        if (next)
                next->prev = prev;
        else
                elem->heap->last = prev;
        if (prev)
                prev->next = next;
        else
                elem->heap->first = next;

        elem->prev = NULL;
        elem->next = NULL;
}

static int
next_elem_is_adjacent(struct malloc_elem *elem)
{
        const struct internal_config *internal_conf =
                eal_get_internal_configuration();

        return elem->next == RTE_PTR_ADD(elem, elem->size) &&
                        elem->next->msl == elem->msl &&
                        (!internal_conf->match_allocations ||
                         elem->orig_elem == elem->next->orig_elem);
}

static int
prev_elem_is_adjacent(struct malloc_elem *elem)
{
        const struct internal_config *internal_conf =
                eal_get_internal_configuration();

        return elem == RTE_PTR_ADD(elem->prev, elem->prev->size) &&
                        elem->prev->msl == elem->msl &&
                        (!internal_conf->match_allocations ||
                         elem->orig_elem == elem->prev->orig_elem);
}

/*
 * Given an element size, compute its freelist index.
 * We free an element into the freelist containing similarly-sized elements.
 * We try to allocate elements starting with the freelist containing
 * similarly-sized elements, and if necessary, we search freelists
 * containing larger elements.
 *
 * Example element size ranges for a heap with five free lists:
 *   heap->free_head[0] - (0   , 2^8]
 *   heap->free_head[1] - (2^8 , 2^10]
 *   heap->free_head[2] - (2^10 ,2^12]
 *   heap->free_head[3] - (2^12, 2^14]
 *   heap->free_head[4] - (2^14, MAX_SIZE]
 */
size_t
malloc_elem_free_list_index(size_t size)
{
#define MALLOC_MINSIZE_LOG2   8
#define MALLOC_LOG2_INCREMENT 2

        size_t log2;
        size_t index;

        if (size <= (1UL << MALLOC_MINSIZE_LOG2))
                return 0;

        /* Find next power of 2 >= size. */
        log2 = sizeof(size) * 8 - __builtin_clzl(size - 1);

        /* Compute freelist index, based on log2(size). */
        index = (log2 - MALLOC_MINSIZE_LOG2 + MALLOC_LOG2_INCREMENT - 1) /
                        MALLOC_LOG2_INCREMENT;

        return index <= RTE_HEAP_NUM_FREELISTS - 1 ?
                        index : RTE_HEAP_NUM_FREELISTS - 1;
}

/*
 * Add the specified element to its heap's free list.
 */
void
malloc_elem_free_list_insert(struct malloc_elem *elem)
{
        size_t idx;

        idx = malloc_elem_free_list_index(elem->size - MALLOC_ELEM_HEADER_LEN);
        elem->state = ELEM_FREE;
        LIST_INSERT_HEAD(&elem->heap->free_head[idx], elem, free_list);
}

/*
 * Remove the specified element from its heap's free list.
 */
void
malloc_elem_free_list_remove(struct malloc_elem *elem)
{
        LIST_REMOVE(elem, free_list);
}

/*
 * reserve a block of data in an existing malloc_elem. If the malloc_elem
 * is much larger than the data block requested, we split the element in two.
 * This function is only called from malloc_heap_alloc so parameter checking
 * is not done here, as it's done there previously.
 */
struct malloc_elem *
malloc_elem_alloc(struct malloc_elem *elem, size_t size, unsigned align,
                size_t bound, bool contig)
{
        struct malloc_elem *new_elem = elem_start_pt(elem, size, align, bound,
                        contig);
        const size_t old_elem_size = (uintptr_t)new_elem - (uintptr_t)elem;
        const size_t trailer_size = elem->size - old_elem_size - size -
                MALLOC_ELEM_OVERHEAD;

        malloc_elem_free_list_remove(elem);

        if (trailer_size > MALLOC_ELEM_OVERHEAD + MIN_DATA_SIZE) {
                /* split it, too much free space after elem */
                struct malloc_elem *new_free_elem =
                                RTE_PTR_ADD(new_elem, size + MALLOC_ELEM_OVERHEAD);

                split_elem(elem, new_free_elem);
                malloc_elem_free_list_insert(new_free_elem);

                if (elem == elem->heap->last)
                        elem->heap->last = new_free_elem;
        }

        if (old_elem_size < MALLOC_ELEM_OVERHEAD + MIN_DATA_SIZE) {
                /* don't split it, pad the element instead */
                elem->state = ELEM_BUSY;
                elem->pad = old_elem_size;

                /* put a dummy header in padding, to point to real element header */
                if (elem->pad > 0) { /* pad will be at least 64-bytes, as everything
                                     * is cache-line aligned */
                        new_elem->pad = elem->pad;
                        new_elem->state = ELEM_PAD;
                        new_elem->size = elem->size - elem->pad;
                        set_header(new_elem);
                }

                return new_elem;
        }

        /* we are going to split the element in two. The original element
         * remains free, and the new element is the one allocated.
         * Re-insert original element, in case its new size makes it
         * belong on a different list.
         */
        split_elem(elem, new_elem);
        new_elem->state = ELEM_BUSY;
        malloc_elem_free_list_insert(elem);

        return new_elem;
}

/*
 * join two struct malloc_elem together. elem1 and elem2 must
 * be contiguous in memory.
 */
static inline void
join_elem(struct malloc_elem *elem1, struct malloc_elem *elem2)
{
        struct malloc_elem *next = elem2->next;
        elem1->size += elem2->size;
        if (next)
                next->prev = elem1;
        else
                elem1->heap->last = elem1;
        elem1->next = next;
        if (elem1->pad) {
                struct malloc_elem *inner = RTE_PTR_ADD(elem1, elem1->pad);
                inner->size = elem1->size - elem1->pad;
        }
}

struct malloc_elem *
malloc_elem_join_adjacent_free(struct malloc_elem *elem)
{
        /*
         * check if next element exists, is adjacent and is free, if so join
         * with it, need to remove from free list.
         */
        if (elem->next != NULL && elem->next->state == ELEM_FREE &&
                        next_elem_is_adjacent(elem)) {
                void *erase;
                size_t erase_len;

                /* we will want to erase the trailer and header */
                erase = RTE_PTR_SUB(elem->next, MALLOC_ELEM_TRAILER_LEN);
                erase_len = MALLOC_ELEM_OVERHEAD + elem->next->pad;

                /* remove from free list, join to this one */
                malloc_elem_free_list_remove(elem->next);
                join_elem(elem, elem->next);

                /* erase header, trailer and pad */
                memset(erase, MALLOC_POISON, erase_len);
        }

        /*
         * check if prev element exists, is adjacent and is free, if so join
         * with it, need to remove from free list.
         */
        if (elem->prev != NULL && elem->prev->state == ELEM_FREE &&
                        prev_elem_is_adjacent(elem)) {
                struct malloc_elem *new_elem;
                void *erase;
                size_t erase_len;

                /* we will want to erase trailer and header */
                erase = RTE_PTR_SUB(elem, MALLOC_ELEM_TRAILER_LEN);
                erase_len = MALLOC_ELEM_OVERHEAD + elem->pad;

                /* remove from free list, join to this one */
                malloc_elem_free_list_remove(elem->prev);

                new_elem = elem->prev;
                join_elem(new_elem, elem);

                /* erase header, trailer and pad */
                memset(erase, MALLOC_POISON, erase_len);

                elem = new_elem;
        }

        return elem;
}

/*
 * free a malloc_elem block by adding it to the free list. If the
 * blocks either immediately before or immediately after newly freed block
 * are also free, the blocks are merged together.
 */
struct malloc_elem *
malloc_elem_free(struct malloc_elem *elem)
{
        void *ptr;
        size_t data_len;

        ptr = RTE_PTR_ADD(elem, MALLOC_ELEM_HEADER_LEN);
        data_len = elem->size - MALLOC_ELEM_OVERHEAD;

        elem = malloc_elem_join_adjacent_free(elem);

        malloc_elem_free_list_insert(elem);

        elem->pad = 0;

        /* decrease heap's count of allocated elements */
        elem->heap->alloc_count--;

        /* poison memory */
        memset(ptr, MALLOC_POISON, data_len);

        return elem;
}

/* assume all checks were already done */
void
malloc_elem_hide_region(struct malloc_elem *elem, void *start, size_t len)
{
        struct malloc_elem *hide_start, *hide_end, *prev, *next;
        size_t len_before, len_after;

        hide_start = start;
        hide_end = RTE_PTR_ADD(start, len);

        prev = elem->prev;
        next = elem->next;

        /* we cannot do anything with non-adjacent elements */
        if (next && next_elem_is_adjacent(elem)) {
                len_after = RTE_PTR_DIFF(next, hide_end);
                if (len_after >= MALLOC_ELEM_OVERHEAD + MIN_DATA_SIZE) {
                        /* split after */
                        split_elem(elem, hide_end);

                        malloc_elem_free_list_insert(hide_end);
                } else if (len_after > 0) {
                        RTE_LOG(ERR, EAL, "Unaligned element, heap is probably corrupt\n");
                        return;
                }
        }

        /* we cannot do anything with non-adjacent elements */
        if (prev && prev_elem_is_adjacent(elem)) {
                len_before = RTE_PTR_DIFF(hide_start, elem);
                if (len_before >= MALLOC_ELEM_OVERHEAD + MIN_DATA_SIZE) {
                        /* split before */
                        split_elem(elem, hide_start);

                        prev = elem;
                        elem = hide_start;

                        malloc_elem_free_list_insert(prev);
                } else if (len_before > 0) {
                        RTE_LOG(ERR, EAL, "Unaligned element, heap is probably corrupt\n");
                        return;
                }
        }

        remove_elem(elem);
}

/*
 * attempt to resize a malloc_elem by expanding into any free space
 * immediately after it in memory.
 */
int
malloc_elem_resize(struct malloc_elem *elem, size_t size)
{
        const size_t new_size = size + elem->pad + MALLOC_ELEM_OVERHEAD;

        /* if we request a smaller size, then always return ok */
        if (elem->size >= new_size)
                return 0;

        /* check if there is a next element, it's free and adjacent */
        if (!elem->next || elem->next->state != ELEM_FREE ||
                        !next_elem_is_adjacent(elem))
                return -1;
        if (elem->size + elem->next->size < new_size)
                return -1;

        /* we now know the element fits, so remove from free list,
         * join the two
         */
        malloc_elem_free_list_remove(elem->next);
        join_elem(elem, elem->next);

        if (elem->size - new_size >= MIN_DATA_SIZE + MALLOC_ELEM_OVERHEAD) {
                /* now we have a big block together. Lets cut it down a bit, by splitting */
                struct malloc_elem *split_pt = RTE_PTR_ADD(elem, new_size);
                split_pt = RTE_PTR_ALIGN_CEIL(split_pt, RTE_CACHE_LINE_SIZE);
                split_elem(elem, split_pt);
                malloc_elem_free_list_insert(split_pt);
        }
        return 0;
}

static inline const char *
elem_state_to_str(enum elem_state state)
{
        switch (state) {
        case ELEM_PAD:
                return "PAD";
        case ELEM_BUSY:
                return "BUSY";
        case ELEM_FREE:
                return "FREE";
        }
        return "ERROR";
}

void
malloc_elem_dump(const struct malloc_elem *elem, FILE *f)
{
        fprintf(f, "Malloc element at %p (%s)\n", elem,
                        elem_state_to_str(elem->state));
        fprintf(f, "  len: 0x%zx pad: 0x%" PRIx32 "\n", elem->size, elem->pad);
        fprintf(f, "  prev: %p next: %p\n", elem->prev, elem->next);
}