// SPDX-License-Identifier: GPL-2.0 /* * Xpram.c -- the S/390 expanded memory RAM-disk * * significant parts of this code are based on * the sbull device driver presented in * A. Rubini: Linux Device Drivers * * Author of XPRAM specific coding: Reinhard Buendgen * buendgen@de.ibm.com * Rewrite for 2.5: Martin Schwidefsky * * External interfaces: * Interfaces to linux kernel * xpram_setup: read kernel parameters * Device specific file operations * xpram_iotcl * xpram_open * * "ad-hoc" partitioning: * the expanded memory can be partitioned among several devices * (with different minors). The partitioning set up can be * set by kernel or module parameters (int devs & int sizes[]) * * Potential future improvements: * generic hard disk support to replace ad-hoc partitioning */ #define KMSG_COMPONENT "xpram" #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt #include #include #include /* isdigit, isxdigit */ #include #include #include #include #include /* HDIO_GETGEO */ #include #include #include #include #include #include #define XPRAM_NAME "xpram" #define XPRAM_DEVS 1 /* one partition */ #define XPRAM_MAX_DEVS 32 /* maximal number of devices (partitions) */ typedef struct { unsigned int size; /* size of xpram segment in pages */ unsigned int offset; /* start page of xpram segment */ } xpram_device_t; static xpram_device_t xpram_devices[XPRAM_MAX_DEVS]; static unsigned int xpram_sizes[XPRAM_MAX_DEVS]; static struct gendisk *xpram_disks[XPRAM_MAX_DEVS]; static struct request_queue *xpram_queues[XPRAM_MAX_DEVS]; static unsigned int xpram_pages; static int xpram_devs; /* * Parameter parsing functions. */ static int devs = XPRAM_DEVS; static char *sizes[XPRAM_MAX_DEVS]; module_param(devs, int, 0); module_param_array(sizes, charp, NULL, 0); MODULE_PARM_DESC(devs, "number of devices (\"partitions\"), " \ "the default is " __MODULE_STRING(XPRAM_DEVS) "\n"); MODULE_PARM_DESC(sizes, "list of device (partition) sizes " \ "the defaults are 0s \n" \ "All devices with size 0 equally partition the " "remaining space on the expanded strorage not " "claimed by explicit sizes\n"); MODULE_LICENSE("GPL"); /* * Copy expanded memory page (4kB) into main memory * Arguments * page_addr: address of target page * xpage_index: index of expandeded memory page * Return value * 0: if operation succeeds * -EIO: if pgin failed * -ENXIO: if xpram has vanished */ static int xpram_page_in (unsigned long page_addr, unsigned int xpage_index) { int cc = 2; /* return unused cc 2 if pgin traps */ asm volatile( " .insn rre,0xb22e0000,%1,%2\n" /* pgin %1,%2 */ "0: ipm %0\n" " srl %0,28\n" "1:\n" EX_TABLE(0b,1b) : "+d" (cc) : "a" (__pa(page_addr)), "d" (xpage_index) : "cc"); if (cc == 3) return -ENXIO; if (cc == 2) return -ENXIO; if (cc == 1) return -EIO; return 0; } /* * Copy a 4kB page of main memory to an expanded memory page * Arguments * page_addr: address of source page * xpage_index: index of expandeded memory page * Return value * 0: if operation succeeds * -EIO: if pgout failed * -ENXIO: if xpram has vanished */ static long xpram_page_out (unsigned long page_addr, unsigned int xpage_index) { int cc = 2; /* return unused cc 2 if pgin traps */ asm volatile( " .insn rre,0xb22f0000,%1,%2\n" /* pgout %1,%2 */ "0: ipm %0\n" " srl %0,28\n" "1:\n" EX_TABLE(0b,1b) : "+d" (cc) : "a" (__pa(page_addr)), "d" (xpage_index) : "cc"); if (cc == 3) return -ENXIO; if (cc == 2) return -ENXIO; if (cc == 1) return -EIO; return 0; } /* * Check if xpram is available. */ static int xpram_present(void) { unsigned long mem_page; int rc; mem_page = (unsigned long) __get_free_page(GFP_KERNEL); if (!mem_page) return -ENOMEM; rc = xpram_page_in(mem_page, 0); free_page(mem_page); return rc ? -ENXIO : 0; } /* * Return index of the last available xpram page. */ static unsigned long xpram_highest_page_index(void) { unsigned int page_index, add_bit; unsigned long mem_page; mem_page = (unsigned long) __get_free_page(GFP_KERNEL); if (!mem_page) return 0; page_index = 0; add_bit = 1ULL << (sizeof(unsigned int)*8 - 1); while (add_bit > 0) { if (xpram_page_in(mem_page, page_index | add_bit) == 0) page_index |= add_bit; add_bit >>= 1; } free_page (mem_page); return page_index; } /* * Block device make request function. */ static blk_qc_t xpram_make_request(struct request_queue *q, struct bio *bio) { xpram_device_t *xdev = bio->bi_disk->private_data; struct bio_vec bvec; struct bvec_iter iter; unsigned int index; unsigned long page_addr; unsigned long bytes; blk_queue_split(q, &bio); if ((bio->bi_iter.bi_sector & 7) != 0 || (bio->bi_iter.bi_size & 4095) != 0) /* Request is not page-aligned. */ goto fail; if ((bio->bi_iter.bi_size >> 12) > xdev->size) /* Request size is no page-aligned. */ goto fail; if ((bio->bi_iter.bi_sector >> 3) > 0xffffffffU - xdev->offset) goto fail; index = (bio->bi_iter.bi_sector >> 3) + xdev->offset; bio_for_each_segment(bvec, bio, iter) { page_addr = (unsigned long) kmap(bvec.bv_page) + bvec.bv_offset; bytes = bvec.bv_len; if ((page_addr & 4095) != 0 || (bytes & 4095) != 0) /* More paranoia. */ goto fail; while (bytes > 0) { if (bio_data_dir(bio) == READ) { if (xpram_page_in(page_addr, index) != 0) goto fail; } else { if (xpram_page_out(page_addr, index) != 0) goto fail; } page_addr += 4096; bytes -= 4096; index++; } } bio_endio(bio); return BLK_QC_T_NONE; fail: bio_io_error(bio); return BLK_QC_T_NONE; } static int xpram_getgeo(struct block_device *bdev, struct hd_geometry *geo) { unsigned long size; /* * get geometry: we have to fake one... trim the size to a * multiple of 64 (32k): tell we have 16 sectors, 4 heads, * whatever cylinders. Tell also that data starts at sector. 4. */ size = (xpram_pages * 8) & ~0x3f; geo->cylinders = size >> 6; geo->heads = 4; geo->sectors = 16; geo->start = 4; return 0; } static const struct block_device_operations xpram_devops = { .owner = THIS_MODULE, .getgeo = xpram_getgeo, }; /* * Setup xpram_sizes array. */ static int __init xpram_setup_sizes(unsigned long pages) { unsigned long mem_needed; unsigned long mem_auto; unsigned long long size; char *sizes_end; int mem_auto_no; int i; /* Check number of devices. */ if (devs <= 0 || devs > XPRAM_MAX_DEVS) { pr_err("%d is not a valid number of XPRAM devices\n",devs); return -EINVAL; } xpram_devs = devs; /* * Copy sizes array to xpram_sizes and align partition * sizes to page boundary. */ mem_needed = 0; mem_auto_no = 0; for (i = 0; i < xpram_devs; i++) { if (sizes[i]) { size = simple_strtoull(sizes[i], &sizes_end, 0); switch (*sizes_end) { case 'g': case 'G': size <<= 20; break; case 'm': case 'M': size <<= 10; } xpram_sizes[i] = (size + 3) & -4UL; } if (xpram_sizes[i]) mem_needed += xpram_sizes[i]; else mem_auto_no++; } pr_info(" number of devices (partitions): %d \n", xpram_devs); for (i = 0; i < xpram_devs; i++) { if (xpram_sizes[i]) pr_info(" size of partition %d: %u kB\n", i, xpram_sizes[i]); else pr_info(" size of partition %d to be set " "automatically\n",i); } pr_info(" memory needed (for sized partitions): %lu kB\n", mem_needed); pr_info(" partitions to be sized automatically: %d\n", mem_auto_no); if (mem_needed > pages * 4) { pr_err("Not enough expanded memory available\n"); return -EINVAL; } /* * partitioning: * xpram_sizes[i] != 0; partition i has size xpram_sizes[i] kB * else: ; all partitions with zero xpram_sizes[i] * partition equally the remaining space */ if (mem_auto_no) { mem_auto = ((pages - mem_needed / 4) / mem_auto_no) * 4; pr_info(" automatically determined " "partition size: %lu kB\n", mem_auto); for (i = 0; i < xpram_devs; i++) if (xpram_sizes[i] == 0) xpram_sizes[i] = mem_auto; } return 0; } static int __init xpram_setup_blkdev(void) { unsigned long offset; int i, rc = -ENOMEM; for (i = 0; i < xpram_devs; i++) { xpram_disks[i] = alloc_disk(1); if (!xpram_disks[i]) goto out; xpram_queues[i] = blk_alloc_queue(GFP_KERNEL); if (!xpram_queues[i]) { put_disk(xpram_disks[i]); goto out; } blk_queue_flag_set(QUEUE_FLAG_NONROT, xpram_queues[i]); blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, xpram_queues[i]); blk_queue_make_request(xpram_queues[i], xpram_make_request); blk_queue_logical_block_size(xpram_queues[i], 4096); } /* * Register xpram major. */ rc = register_blkdev(XPRAM_MAJOR, XPRAM_NAME); if (rc < 0) goto out; /* * Setup device structures. */ offset = 0; for (i = 0; i < xpram_devs; i++) { struct gendisk *disk = xpram_disks[i]; xpram_devices[i].size = xpram_sizes[i] / 4; xpram_devices[i].offset = offset; offset += xpram_devices[i].size; disk->major = XPRAM_MAJOR; disk->first_minor = i; disk->fops = &xpram_devops; disk->private_data = &xpram_devices[i]; disk->queue = xpram_queues[i]; sprintf(disk->disk_name, "slram%d", i); set_capacity(disk, xpram_sizes[i] << 1); add_disk(disk); } return 0; out: while (i--) { blk_cleanup_queue(xpram_queues[i]); put_disk(xpram_disks[i]); } return rc; } /* * Resume failed: Print error message and call panic. */ static void xpram_resume_error(const char *message) { pr_err("Resuming the system failed: %s\n", message); panic("xpram resume error\n"); } /* * Check if xpram setup changed between suspend and resume. */ static int xpram_restore(struct device *dev) { if (!xpram_pages) return 0; if (xpram_present() != 0) xpram_resume_error("xpram disappeared"); if (xpram_pages != xpram_highest_page_index() + 1) xpram_resume_error("Size of xpram changed"); return 0; } static const struct dev_pm_ops xpram_pm_ops = { .restore = xpram_restore, }; static struct platform_driver xpram_pdrv = { .driver = { .name = XPRAM_NAME, .pm = &xpram_pm_ops, }, }; static struct platform_device *xpram_pdev; /* * Finally, the init/exit functions. */ static void __exit xpram_exit(void) { int i; for (i = 0; i < xpram_devs; i++) { del_gendisk(xpram_disks[i]); blk_cleanup_queue(xpram_queues[i]); put_disk(xpram_disks[i]); } unregister_blkdev(XPRAM_MAJOR, XPRAM_NAME); platform_device_unregister(xpram_pdev); platform_driver_unregister(&xpram_pdrv); } static int __init xpram_init(void) { int rc; /* Find out size of expanded memory. */ if (xpram_present() != 0) { pr_err("No expanded memory available\n"); return -ENODEV; } xpram_pages = xpram_highest_page_index() + 1; pr_info(" %u pages expanded memory found (%lu KB).\n", xpram_pages, (unsigned long) xpram_pages*4); rc = xpram_setup_sizes(xpram_pages); if (rc) return rc; rc = platform_driver_register(&xpram_pdrv); if (rc) return rc; xpram_pdev = platform_device_register_simple(XPRAM_NAME, -1, NULL, 0); if (IS_ERR(xpram_pdev)) { rc = PTR_ERR(xpram_pdev); goto fail_platform_driver_unregister; } rc = xpram_setup_blkdev(); if (rc) goto fail_platform_device_unregister; return 0; fail_platform_device_unregister: platform_device_unregister(xpram_pdev); fail_platform_driver_unregister: platform_driver_unregister(&xpram_pdrv); return rc; } module_init(xpram_init); module_exit(xpram_exit);