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f629576662
The sysfs core now allows instances of 'struct bin_attribute' to be moved into read-only memory. Make use of that to protect them against accidental or malicious modifications. Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Link: https://lore.kernel.org/r/20241216-sysfs-const-bin_attr-powerpc-v1-3-bbed8906f476@weissschuh.net Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
71 lines
1.6 KiB
C
71 lines
1.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Ultravisor high level interfaces
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*
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* Copyright 2019, IBM Corporation.
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*
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*/
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#include <linux/init.h>
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#include <linux/printk.h>
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#include <linux/of_fdt.h>
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#include <linux/of.h>
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#include <asm/ultravisor.h>
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#include <asm/firmware.h>
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#include <asm/machdep.h>
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#include "powernv.h"
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static struct kobject *ultravisor_kobj;
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int __init early_init_dt_scan_ultravisor(unsigned long node, const char *uname,
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int depth, void *data)
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{
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if (!of_flat_dt_is_compatible(node, "ibm,ultravisor"))
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return 0;
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powerpc_firmware_features |= FW_FEATURE_ULTRAVISOR;
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pr_debug("Ultravisor detected!\n");
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return 1;
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}
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static struct memcons *uv_memcons;
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static ssize_t uv_msglog_read(struct file *file, struct kobject *kobj,
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const struct bin_attribute *bin_attr, char *to,
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loff_t pos, size_t count)
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{
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return memcons_copy(uv_memcons, to, pos, count);
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}
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static struct bin_attribute uv_msglog_attr __ro_after_init = {
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.attr = {.name = "msglog", .mode = 0400},
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.read_new = uv_msglog_read
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};
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static int __init uv_init(void)
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{
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struct device_node *node;
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if (!firmware_has_feature(FW_FEATURE_ULTRAVISOR))
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return 0;
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node = of_find_compatible_node(NULL, NULL, "ibm,uv-firmware");
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if (!node)
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return -ENODEV;
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uv_memcons = memcons_init(node, "memcons");
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of_node_put(node);
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if (!uv_memcons)
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return -ENOENT;
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uv_msglog_attr.size = memcons_get_size(uv_memcons);
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ultravisor_kobj = kobject_create_and_add("ultravisor", firmware_kobj);
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if (!ultravisor_kobj)
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return -ENOMEM;
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return sysfs_create_bin_file(ultravisor_kobj, &uv_msglog_attr);
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}
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machine_subsys_initcall(powernv, uv_init);
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