cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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device.c (2323B)

      1// SPDX-License-Identifier: GPL-2.0
      2#include <linux/platform_device.h>
      3#include <linux/memregion.h>
      4#include <linux/module.h>
      5#include <linux/dax.h>
      6#include <linux/mm.h>
      7
      8static bool nohmem;
      9module_param_named(disable, nohmem, bool, 0444);
     10
     11void hmem_register_device(int target_nid, struct resource *r)
     12{
     13	/* define a clean / non-busy resource for the platform device */
     14	struct resource res = {
     15		.start = r->start,
     16		.end = r->end,
     17		.flags = IORESOURCE_MEM,
     18	};
     19	struct platform_device *pdev;
     20	struct memregion_info info;
     21	int rc, id;
     22
     23	if (nohmem)
     24		return;
     25
     26	rc = region_intersects(res.start, resource_size(&res), IORESOURCE_MEM,
     27			IORES_DESC_SOFT_RESERVED);
     28	if (rc != REGION_INTERSECTS)
     29		return;
     30
     31	id = memregion_alloc(GFP_KERNEL);
     32	if (id < 0) {
     33		pr_err("memregion allocation failure for %pr\n", &res);
     34		return;
     35	}
     36
     37	pdev = platform_device_alloc("hmem", id);
     38	if (!pdev) {
     39		pr_err("hmem device allocation failure for %pr\n", &res);
     40		goto out_pdev;
     41	}
     42
     43	pdev->dev.numa_node = numa_map_to_online_node(target_nid);
     44	info = (struct memregion_info) {
     45		.target_node = target_nid,
     46	};
     47	rc = platform_device_add_data(pdev, &info, sizeof(info));
     48	if (rc < 0) {
     49		pr_err("hmem memregion_info allocation failure for %pr\n", &res);
     50		goto out_pdev;
     51	}
     52
     53	rc = platform_device_add_resources(pdev, &res, 1);
     54	if (rc < 0) {
     55		pr_err("hmem resource allocation failure for %pr\n", &res);
     56		goto out_resource;
     57	}
     58
     59	rc = platform_device_add(pdev);
     60	if (rc < 0) {
     61		dev_err(&pdev->dev, "device add failed for %pr\n", &res);
     62		goto out_resource;
     63	}
     64
     65	return;
     66
     67out_resource:
     68	put_device(&pdev->dev);
     69out_pdev:
     70	memregion_free(id);
     71}
     72
     73static __init int hmem_register_one(struct resource *res, void *data)
     74{
     75	/*
     76	 * If the resource is not a top-level resource it was already
     77	 * assigned to a device by the HMAT parsing.
     78	 */
     79	if (res->parent != &iomem_resource) {
     80		pr_info("HMEM: skip %pr, already claimed\n", res);
     81		return 0;
     82	}
     83
     84	hmem_register_device(phys_to_target_node(res->start), res);
     85
     86	return 0;
     87}
     88
     89static __init int hmem_init(void)
     90{
     91	walk_iomem_res_desc(IORES_DESC_SOFT_RESERVED,
     92			IORESOURCE_MEM, 0, -1, NULL, hmem_register_one);
     93	return 0;
     94}
     95
     96/*
     97 * As this is a fallback for address ranges unclaimed by the ACPI HMAT
     98 * parsing it must be at an initcall level greater than hmat_init().
     99 */
    100late_initcall(hmem_init);