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_lpat.c (4139B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * acpi_lpat.c - LPAT table processing functions
      4 *
      5 * Copyright (C) 2015 Intel Corporation. All rights reserved.
      6 */
      7
      8#include <linux/export.h>
      9#include <linux/acpi.h>
     10#include <acpi/acpi_lpat.h>
     11
     12/**
     13 * acpi_lpat_raw_to_temp(): Return temperature from raw value through
     14 * LPAT conversion table
     15 *
     16 * @lpat_table: the temperature_raw mapping table structure
     17 * @raw: the raw value, used as a key to get the temperature from the
     18 *       above mapping table
     19 *
     20 * A positive converted temperature value will be returned on success,
     21 * a negative errno will be returned in error cases.
     22 */
     23int acpi_lpat_raw_to_temp(struct acpi_lpat_conversion_table *lpat_table,
     24			  int raw)
     25{
     26	int i, delta_temp, delta_raw, temp;
     27	struct acpi_lpat *lpat = lpat_table->lpat;
     28
     29	for (i = 0; i < lpat_table->lpat_count - 1; i++) {
     30		if ((raw >= lpat[i].raw && raw <= lpat[i+1].raw) ||
     31		    (raw <= lpat[i].raw && raw >= lpat[i+1].raw))
     32			break;
     33	}
     34
     35	if (i == lpat_table->lpat_count - 1)
     36		return -ENOENT;
     37
     38	delta_temp = lpat[i+1].temp - lpat[i].temp;
     39	delta_raw = lpat[i+1].raw - lpat[i].raw;
     40	temp = lpat[i].temp + (raw - lpat[i].raw) * delta_temp / delta_raw;
     41
     42	return temp;
     43}
     44EXPORT_SYMBOL_GPL(acpi_lpat_raw_to_temp);
     45
     46/**
     47 * acpi_lpat_temp_to_raw(): Return raw value from temperature through
     48 * LPAT conversion table
     49 *
     50 * @lpat_table: the temperature_raw mapping table
     51 * @temp: the temperature, used as a key to get the raw value from the
     52 *        above mapping table
     53 *
     54 * The raw value will be returned on success,
     55 * a negative errno will be returned in error cases.
     56 */
     57int acpi_lpat_temp_to_raw(struct acpi_lpat_conversion_table *lpat_table,
     58			  int temp)
     59{
     60	int i, delta_temp, delta_raw, raw;
     61	struct acpi_lpat *lpat = lpat_table->lpat;
     62
     63	for (i = 0; i < lpat_table->lpat_count - 1; i++) {
     64		if (temp >= lpat[i].temp && temp <= lpat[i+1].temp)
     65			break;
     66	}
     67
     68	if (i ==  lpat_table->lpat_count - 1)
     69		return -ENOENT;
     70
     71	delta_temp = lpat[i+1].temp - lpat[i].temp;
     72	delta_raw = lpat[i+1].raw - lpat[i].raw;
     73	raw = lpat[i].raw + (temp - lpat[i].temp) * delta_raw / delta_temp;
     74
     75	return raw;
     76}
     77EXPORT_SYMBOL_GPL(acpi_lpat_temp_to_raw);
     78
     79/**
     80 * acpi_lpat_get_conversion_table(): Parse ACPI LPAT table if present.
     81 *
     82 * @handle: Handle to acpi device
     83 *
     84 * Parse LPAT table to a struct of type acpi_lpat_table. On success
     85 * it returns a pointer to newly allocated table. This table must
     86 * be freed by the caller when finished processing, using a call to
     87 * acpi_lpat_free_conversion_table.
     88 */
     89struct acpi_lpat_conversion_table *acpi_lpat_get_conversion_table(acpi_handle
     90								  handle)
     91{
     92	struct acpi_lpat_conversion_table *lpat_table = NULL;
     93	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
     94	union acpi_object *obj_p, *obj_e;
     95	int *lpat, i;
     96	acpi_status status;
     97
     98	status = acpi_evaluate_object(handle, "LPAT", NULL, &buffer);
     99	if (ACPI_FAILURE(status))
    100		return NULL;
    101
    102	obj_p = (union acpi_object *)buffer.pointer;
    103	if (!obj_p || (obj_p->type != ACPI_TYPE_PACKAGE) ||
    104	    (obj_p->package.count % 2) || (obj_p->package.count < 4))
    105		goto out;
    106
    107	lpat = kcalloc(obj_p->package.count, sizeof(int), GFP_KERNEL);
    108	if (!lpat)
    109		goto out;
    110
    111	for (i = 0; i < obj_p->package.count; i++) {
    112		obj_e = &obj_p->package.elements[i];
    113		if (obj_e->type != ACPI_TYPE_INTEGER) {
    114			kfree(lpat);
    115			goto out;
    116		}
    117		lpat[i] = (s64)obj_e->integer.value;
    118	}
    119
    120	lpat_table = kzalloc(sizeof(*lpat_table), GFP_KERNEL);
    121	if (!lpat_table) {
    122		kfree(lpat);
    123		goto out;
    124	}
    125
    126	lpat_table->lpat = (struct acpi_lpat *)lpat;
    127	lpat_table->lpat_count = obj_p->package.count / 2;
    128
    129out:
    130	kfree(buffer.pointer);
    131	return lpat_table;
    132}
    133EXPORT_SYMBOL_GPL(acpi_lpat_get_conversion_table);
    134
    135/**
    136 * acpi_lpat_free_conversion_table(): Free LPAT table.
    137 *
    138 * @lpat_table: the temperature_raw mapping table structure
    139 *
    140 * Frees the LPAT table previously allocated by a call to
    141 * acpi_lpat_get_conversion_table.
    142 */
    143void acpi_lpat_free_conversion_table(struct acpi_lpat_conversion_table
    144				     *lpat_table)
    145{
    146	if (lpat_table) {
    147		kfree(lpat_table->lpat);
    148		kfree(lpat_table);
    149	}
    150}
    151EXPORT_SYMBOL_GPL(acpi_lpat_free_conversion_table);