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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ultravisor.c (1614B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * Ultravisor high level interfaces
      4 *
      5 * Copyright 2019, IBM Corporation.
      6 *
      7 */
      8#include <linux/init.h>
      9#include <linux/printk.h>
     10#include <linux/of_fdt.h>
     11#include <linux/of.h>
     12
     13#include <asm/ultravisor.h>
     14#include <asm/firmware.h>
     15#include <asm/machdep.h>
     16
     17#include "powernv.h"
     18
     19static struct kobject *ultravisor_kobj;
     20
     21int __init early_init_dt_scan_ultravisor(unsigned long node, const char *uname,
     22					 int depth, void *data)
     23{
     24	if (!of_flat_dt_is_compatible(node, "ibm,ultravisor"))
     25		return 0;
     26
     27	powerpc_firmware_features |= FW_FEATURE_ULTRAVISOR;
     28	pr_debug("Ultravisor detected!\n");
     29	return 1;
     30}
     31
     32static struct memcons *uv_memcons;
     33
     34static ssize_t uv_msglog_read(struct file *file, struct kobject *kobj,
     35			      struct bin_attribute *bin_attr, char *to,
     36			      loff_t pos, size_t count)
     37{
     38	return memcons_copy(uv_memcons, to, pos, count);
     39}
     40
     41static struct bin_attribute uv_msglog_attr = {
     42	.attr = {.name = "msglog", .mode = 0400},
     43	.read = uv_msglog_read
     44};
     45
     46static int __init uv_init(void)
     47{
     48	struct device_node *node;
     49
     50	if (!firmware_has_feature(FW_FEATURE_ULTRAVISOR))
     51		return 0;
     52
     53	node = of_find_compatible_node(NULL, NULL, "ibm,uv-firmware");
     54	if (!node)
     55		return -ENODEV;
     56
     57	uv_memcons = memcons_init(node, "memcons");
     58	of_node_put(node);
     59	if (!uv_memcons)
     60		return -ENOENT;
     61
     62	uv_msglog_attr.size = memcons_get_size(uv_memcons);
     63
     64	ultravisor_kobj = kobject_create_and_add("ultravisor", firmware_kobj);
     65	if (!ultravisor_kobj)
     66		return -ENOMEM;
     67
     68	return sysfs_create_bin_file(ultravisor_kobj, &uv_msglog_attr);
     69}
     70machine_subsys_initcall(powernv, uv_init);