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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acpi-ext.c (2673B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * (c) Copyright 2003, 2006 Hewlett-Packard Development Company, L.P.
      4 *	Alex Williamson <alex.williamson@hp.com>
      5 *	Bjorn Helgaas <bjorn.helgaas@hp.com>
      6 */
      7
      8#include <linux/module.h>
      9#include <linux/types.h>
     10#include <linux/slab.h>
     11#include <linux/acpi.h>
     12
     13#include <asm/acpi-ext.h>
     14
     15/*
     16 * Device CSRs that do not appear in PCI config space should be described
     17 * via ACPI.  This would normally be done with Address Space Descriptors
     18 * marked as "consumer-only," but old versions of Windows and Linux ignore
     19 * the producer/consumer flag, so HP invented a vendor-defined resource to
     20 * describe the location and size of CSR space.
     21 */
     22
     23struct acpi_vendor_uuid hp_ccsr_uuid = {
     24	.subtype = 2,
     25	.data = { 0xf9, 0xad, 0xe9, 0x69, 0x4f, 0x92, 0x5f, 0xab, 0xf6, 0x4a,
     26	    0x24, 0xd2, 0x01, 0x37, 0x0e, 0xad },
     27};
     28
     29static acpi_status hp_ccsr_locate(acpi_handle obj, u64 *base, u64 *length)
     30{
     31	acpi_status status;
     32	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
     33	struct acpi_resource *resource;
     34	struct acpi_resource_vendor_typed *vendor;
     35
     36	status = acpi_get_vendor_resource(obj, METHOD_NAME__CRS, &hp_ccsr_uuid,
     37		&buffer);
     38
     39	resource = buffer.pointer;
     40	vendor = &resource->data.vendor_typed;
     41
     42	if (ACPI_FAILURE(status) || vendor->byte_length < 16) {
     43		status = AE_NOT_FOUND;
     44		goto exit;
     45	}
     46
     47	memcpy(base, vendor->byte_data, sizeof(*base));
     48	memcpy(length, vendor->byte_data + 8, sizeof(*length));
     49
     50  exit:
     51	kfree(buffer.pointer);
     52	return status;
     53}
     54
     55struct csr_space {
     56	u64	base;
     57	u64	length;
     58};
     59
     60static acpi_status find_csr_space(struct acpi_resource *resource, void *data)
     61{
     62	struct csr_space *space = data;
     63	struct acpi_resource_address64 addr;
     64	acpi_status status;
     65
     66	status = acpi_resource_to_address64(resource, &addr);
     67	if (ACPI_SUCCESS(status) &&
     68	    addr.resource_type == ACPI_MEMORY_RANGE &&
     69	    addr.address.address_length &&
     70	    addr.producer_consumer == ACPI_CONSUMER) {
     71		space->base = addr.address.minimum;
     72		space->length = addr.address.address_length;
     73		return AE_CTRL_TERMINATE;
     74	}
     75	return AE_OK;		/* keep looking */
     76}
     77
     78static acpi_status hp_crs_locate(acpi_handle obj, u64 *base, u64 *length)
     79{
     80	struct csr_space space = { 0, 0 };
     81
     82	acpi_walk_resources(obj, METHOD_NAME__CRS, find_csr_space, &space);
     83	if (!space.length)
     84		return AE_NOT_FOUND;
     85
     86	*base = space.base;
     87	*length = space.length;
     88	return AE_OK;
     89}
     90
     91acpi_status hp_acpi_csr_space(acpi_handle obj, u64 *csr_base, u64 *csr_length)
     92{
     93	acpi_status status;
     94
     95	status = hp_ccsr_locate(obj, csr_base, csr_length);
     96	if (ACPI_SUCCESS(status))
     97		return status;
     98
     99	return hp_crs_locate(obj, csr_base, csr_length);
    100}
    101EXPORT_SYMBOL(hp_acpi_csr_space);