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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qcom_pil_info.c (3097B)

      1// SPDX-License-Identifier: GPL-2.0-only
      2/*
      3 * Copyright (c) 2019-2020 Linaro Ltd.
      4 */
      5#include <linux/kernel.h>
      6#include <linux/module.h>
      7#include <linux/mutex.h>
      8#include <linux/of_address.h>
      9#include "qcom_pil_info.h"
     10
     11/*
     12 * The PIL relocation information region is used to communicate memory regions
     13 * occupied by co-processor firmware for post mortem crash analysis.
     14 *
     15 * It consists of an array of entries with an 8 byte textual identifier of the
     16 * region followed by a 64 bit base address and 32 bit size, both little
     17 * endian.
     18 */
     19#define PIL_RELOC_NAME_LEN	8
     20#define PIL_RELOC_ENTRY_SIZE	(PIL_RELOC_NAME_LEN + sizeof(__le64) + sizeof(__le32))
     21
     22struct pil_reloc {
     23	void __iomem *base;
     24	size_t num_entries;
     25};
     26
     27static struct pil_reloc _reloc __read_mostly;
     28static DEFINE_MUTEX(pil_reloc_lock);
     29
     30static int qcom_pil_info_init(void)
     31{
     32	struct device_node *np;
     33	struct resource imem;
     34	void __iomem *base;
     35	int ret;
     36
     37	/* Already initialized? */
     38	if (_reloc.base)
     39		return 0;
     40
     41	np = of_find_compatible_node(NULL, NULL, "qcom,pil-reloc-info");
     42	if (!np)
     43		return -ENOENT;
     44
     45	ret = of_address_to_resource(np, 0, &imem);
     46	of_node_put(np);
     47	if (ret < 0)
     48		return ret;
     49
     50	base = ioremap(imem.start, resource_size(&imem));
     51	if (!base) {
     52		pr_err("failed to map PIL relocation info region\n");
     53		return -ENOMEM;
     54	}
     55
     56	memset_io(base, 0, resource_size(&imem));
     57
     58	_reloc.base = base;
     59	_reloc.num_entries = (u32)resource_size(&imem) / PIL_RELOC_ENTRY_SIZE;
     60
     61	return 0;
     62}
     63
     64/**
     65 * qcom_pil_info_store() - store PIL information of image in IMEM
     66 * @image:	name of the image
     67 * @base:	base address of the loaded image
     68 * @size:	size of the loaded image
     69 *
     70 * Return: 0 on success, negative errno on failure
     71 */
     72int qcom_pil_info_store(const char *image, phys_addr_t base, size_t size)
     73{
     74	char buf[PIL_RELOC_NAME_LEN];
     75	void __iomem *entry;
     76	int ret;
     77	int i;
     78
     79	mutex_lock(&pil_reloc_lock);
     80	ret = qcom_pil_info_init();
     81	if (ret < 0) {
     82		mutex_unlock(&pil_reloc_lock);
     83		return ret;
     84	}
     85
     86	for (i = 0; i < _reloc.num_entries; i++) {
     87		entry = _reloc.base + i * PIL_RELOC_ENTRY_SIZE;
     88
     89		memcpy_fromio(buf, entry, PIL_RELOC_NAME_LEN);
     90
     91		/*
     92		 * An empty record means we didn't find it, given that the
     93		 * records are packed.
     94		 */
     95		if (!buf[0])
     96			goto found_unused;
     97
     98		if (!strncmp(buf, image, PIL_RELOC_NAME_LEN))
     99			goto found_existing;
    100	}
    101
    102	pr_warn("insufficient PIL info slots\n");
    103	mutex_unlock(&pil_reloc_lock);
    104	return -ENOMEM;
    105
    106found_unused:
    107	memcpy_toio(entry, image, strnlen(image, PIL_RELOC_NAME_LEN));
    108found_existing:
    109	/* Use two writel() as base is only aligned to 4 bytes on odd entries */
    110	writel(base, entry + PIL_RELOC_NAME_LEN);
    111	writel((u64)base >> 32, entry + PIL_RELOC_NAME_LEN + 4);
    112	writel(size, entry + PIL_RELOC_NAME_LEN + sizeof(__le64));
    113	mutex_unlock(&pil_reloc_lock);
    114
    115	return 0;
    116}
    117EXPORT_SYMBOL_GPL(qcom_pil_info_store);
    118
    119static void __exit pil_reloc_exit(void)
    120{
    121	mutex_lock(&pil_reloc_lock);
    122	iounmap(_reloc.base);
    123	_reloc.base = NULL;
    124	mutex_unlock(&pil_reloc_lock);
    125}
    126module_exit(pil_reloc_exit);
    127
    128MODULE_DESCRIPTION("Qualcomm PIL relocation info");
    129MODULE_LICENSE("GPL v2");