// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * SPU core dump code
 *
 * (C) Copyright 2006 IBM Corp.
 *
 * Author: Dwayne Grant McConnell <decimal@us.ibm.com>
 */

#include <linux/elf.h>
#include <linux/file.h>
#include <linux/fdtable.h>
#include <linux/fs.h>
#include <linux/gfp.h>
#include <linux/list.h>
#include <linux/syscalls.h>
#include <linux/coredump.h>
#include <linux/binfmts.h>

#include <linux/uaccess.h>

#include "spufs.h"

static ssize_t do_coredump_read(int num, struct spu_context *ctx, void *buffer,
                                size_t size, loff_t *off)
{
        u64 data;
        int ret;

        if (spufs_coredump_read[num].read)
                return spufs_coredump_read[num].read(ctx, buffer, size, off);

        data = spufs_coredump_read[num].get(ctx);
        ret = snprintf(buffer, size, "0x%.16llx", data);
        if (ret >= size)
                return size;
        return ++ret; /* count trailing NULL */
}

static int spufs_ctx_note_size(struct spu_context *ctx, int dfd)
{
        int i, sz, total = 0;
        char *name;
        char fullname[80];

        for (i = 0; spufs_coredump_read[i].name != NULL; i++) {
                name = spufs_coredump_read[i].name;
                sz = spufs_coredump_read[i].size;

                sprintf(fullname, "SPU/%d/%s", dfd, name);

                total += sizeof(struct elf_note);
                total += roundup(strlen(fullname) + 1, 4);
                total += roundup(sz, 4);
        }

        return total;
}

static int match_context(const void *v, struct file *file, unsigned fd)
{
        struct spu_context *ctx;
        if (file->f_op != &spufs_context_fops)
                return 0;
        ctx = SPUFS_I(file_inode(file))->i_ctx;
        if (ctx->flags & SPU_CREATE_NOSCHED)
                return 0;
        return fd + 1;
}

/*
 * The additional architecture-specific notes for Cell are various
 * context files in the spu context.
 *
 * This function iterates over all open file descriptors and sees
 * if they are a directory in spufs.  In that case we use spufs
 * internal functionality to dump them without needing to actually
 * open the files.
 */
/*
 * descriptor table is not shared, so files can't change or go away.
 */
static struct spu_context *coredump_next_context(int *fd)
{
        struct file *file;
        int n = iterate_fd(current->files, *fd, match_context, NULL);
        if (!n)
                return NULL;
        *fd = n - 1;
        file = fcheck(*fd);
        return SPUFS_I(file_inode(file))->i_ctx;
}

int spufs_coredump_extra_notes_size(void)
{
        struct spu_context *ctx;
        int size = 0, rc, fd;

        fd = 0;
        while ((ctx = coredump_next_context(&fd)) != NULL) {
                rc = spu_acquire_saved(ctx);
                if (rc)
                        break;
                rc = spufs_ctx_note_size(ctx, fd);
                spu_release_saved(ctx);
                if (rc < 0)
                        break;

                size += rc;

                /* start searching the next fd next time */
                fd++;
        }

        return size;
}

static int spufs_arch_write_note(struct spu_context *ctx, int i,
                                  struct coredump_params *cprm, int dfd)
{
        loff_t pos = 0;
        int sz, rc, total = 0;
        const int bufsz = PAGE_SIZE;
        char *name;
        char fullname[80], *buf;
        struct elf_note en;
        size_t skip;

        buf = (void *)get_zeroed_page(GFP_KERNEL);
        if (!buf)
                return -ENOMEM;

        name = spufs_coredump_read[i].name;
        sz = spufs_coredump_read[i].size;

        sprintf(fullname, "SPU/%d/%s", dfd, name);
        en.n_namesz = strlen(fullname) + 1;
        en.n_descsz = sz;
        en.n_type = NT_SPU;

        if (!dump_emit(cprm, &en, sizeof(en)))
                goto Eio;

        if (!dump_emit(cprm, fullname, en.n_namesz))
                goto Eio;

        if (!dump_align(cprm, 4))
                goto Eio;

        do {
                rc = do_coredump_read(i, ctx, buf, bufsz, &pos);
                if (rc > 0) {
                        if (!dump_emit(cprm, buf, rc))
                                goto Eio;
                        total += rc;
                }
        } while (rc == bufsz && total < sz);

        if (rc < 0)
                goto out;

        skip = roundup(cprm->pos - total + sz, 4) - cprm->pos;
        if (!dump_skip(cprm, skip))
                goto Eio;

        rc = 0;
out:
        free_page((unsigned long)buf);
        return rc;
Eio:
        free_page((unsigned long)buf);
        return -EIO;
}

int spufs_coredump_extra_notes_write(struct coredump_params *cprm)
{
        struct spu_context *ctx;
        int fd, j, rc;

        fd = 0;
        while ((ctx = coredump_next_context(&fd)) != NULL) {
                rc = spu_acquire_saved(ctx);
                if (rc)
                        return rc;

                for (j = 0; spufs_coredump_read[j].name != NULL; j++) {
                        rc = spufs_arch_write_note(ctx, j, cprm, fd);
                        if (rc) {
                                spu_release_saved(ctx);
                                return rc;
                        }
                }

                spu_release_saved(ctx);

                /* start searching the next fd next time */
                fd++;
        }

        return 0;
}