// 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 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 spu_context *ctx = NULL;
        struct file *file;
        int n = iterate_fd(current->files, *fd, match_context, NULL);
        if (!n)
                return NULL;
        *fd = n - 1;

        file = fget_raw(*fd);
        if (file) {
                ctx = SPUFS_I(file_inode(file))->i_ctx;
                get_spu_context(ctx);
                fput(file);
        }

        return 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) {
                        put_spu_context(ctx);
                        break;
                }

                rc = spufs_ctx_note_size(ctx, fd);
                spu_release_saved(ctx);
                if (rc < 0) {
                        put_spu_context(ctx);
                        break;
                }

                size += rc;

                /* start searching the next fd next time */
                fd++;
                put_spu_context(ctx);
        }

        return size;
}

static int spufs_arch_write_note(struct spu_context *ctx, int i,
                                  struct coredump_params *cprm, int dfd)
{
        size_t sz = spufs_coredump_read[i].size;
        char fullname[80];
        struct elf_note en;
        int ret;

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

        if (!dump_emit(cprm, &en, sizeof(en)))
                return -EIO;
        if (!dump_emit(cprm, fullname, en.n_namesz))
                return -EIO;
        if (!dump_align(cprm, 4))
                return -EIO;

        if (spufs_coredump_read[i].dump) {
                ret = spufs_coredump_read[i].dump(ctx, cprm);
                if (ret < 0)
                        return ret;
        } else {
                char buf[32];

                ret = snprintf(buf, sizeof(buf), "0x%.16llx",
                               spufs_coredump_read[i].get(ctx));
                if (ret >= sizeof(buf))
                        return sizeof(buf);

                /* count trailing the NULL: */
                if (!dump_emit(cprm, buf, ret + 1))
                        return -EIO;
        }

        dump_skip_to(cprm, roundup(cprm->pos - ret + sz, 4));
        return 0;
}

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;
}