mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-27 01:55:16 +07:00
7b62f9bd22
Currently the opal log is globally readable. It is kernel policy to
limit the visibility of physical addresses / kernel pointers to root.
Given this and the fact the opal log may contain this information it
would be better to limit the readability to root.
Fixes: bfc36894a4 ("powerpc/powernv: Add OPAL message log interface")
Cc: stable@vger.kernel.org # v3.15+
Signed-off-by: Jordan Niethe <jniethe5@gmail.com>
Reviewed-by: Stewart Smith <stewart@linux.ibm.com>
Reviewed-by: Andrew Donnellan <andrew.donnellan@au1.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
143 lines
3.3 KiB
C
143 lines
3.3 KiB
C
/*
|
|
* PowerNV OPAL in-memory console interface
|
|
*
|
|
* Copyright 2014 IBM Corp.
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation; either version
|
|
* 2 of the License, or (at your option) any later version.
|
|
*/
|
|
|
|
#include <asm/io.h>
|
|
#include <asm/opal.h>
|
|
#include <linux/debugfs.h>
|
|
#include <linux/of.h>
|
|
#include <linux/types.h>
|
|
#include <asm/barrier.h>
|
|
|
|
/* OPAL in-memory console. Defined in OPAL source at core/console.c */
|
|
struct memcons {
|
|
__be64 magic;
|
|
#define MEMCONS_MAGIC 0x6630696567726173L
|
|
__be64 obuf_phys;
|
|
__be64 ibuf_phys;
|
|
__be32 obuf_size;
|
|
__be32 ibuf_size;
|
|
__be32 out_pos;
|
|
#define MEMCONS_OUT_POS_WRAP 0x80000000u
|
|
#define MEMCONS_OUT_POS_MASK 0x00ffffffu
|
|
__be32 in_prod;
|
|
__be32 in_cons;
|
|
};
|
|
|
|
static struct memcons *opal_memcons = NULL;
|
|
|
|
ssize_t opal_msglog_copy(char *to, loff_t pos, size_t count)
|
|
{
|
|
const char *conbuf;
|
|
ssize_t ret;
|
|
size_t first_read = 0;
|
|
uint32_t out_pos, avail;
|
|
|
|
if (!opal_memcons)
|
|
return -ENODEV;
|
|
|
|
out_pos = be32_to_cpu(READ_ONCE(opal_memcons->out_pos));
|
|
|
|
/* Now we've read out_pos, put a barrier in before reading the new
|
|
* data it points to in conbuf. */
|
|
smp_rmb();
|
|
|
|
conbuf = phys_to_virt(be64_to_cpu(opal_memcons->obuf_phys));
|
|
|
|
/* When the buffer has wrapped, read from the out_pos marker to the end
|
|
* of the buffer, and then read the remaining data as in the un-wrapped
|
|
* case. */
|
|
if (out_pos & MEMCONS_OUT_POS_WRAP) {
|
|
|
|
out_pos &= MEMCONS_OUT_POS_MASK;
|
|
avail = be32_to_cpu(opal_memcons->obuf_size) - out_pos;
|
|
|
|
ret = memory_read_from_buffer(to, count, &pos,
|
|
conbuf + out_pos, avail);
|
|
|
|
if (ret < 0)
|
|
goto out;
|
|
|
|
first_read = ret;
|
|
to += first_read;
|
|
count -= first_read;
|
|
pos -= avail;
|
|
|
|
if (count <= 0)
|
|
goto out;
|
|
}
|
|
|
|
/* Sanity check. The firmware should not do this to us. */
|
|
if (out_pos > be32_to_cpu(opal_memcons->obuf_size)) {
|
|
pr_err("OPAL: memory console corruption. Aborting read.\n");
|
|
return -EINVAL;
|
|
}
|
|
|
|
ret = memory_read_from_buffer(to, count, &pos, conbuf, out_pos);
|
|
|
|
if (ret < 0)
|
|
goto out;
|
|
|
|
ret += first_read;
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
static ssize_t opal_msglog_read(struct file *file, struct kobject *kobj,
|
|
struct bin_attribute *bin_attr, char *to,
|
|
loff_t pos, size_t count)
|
|
{
|
|
return opal_msglog_copy(to, pos, count);
|
|
}
|
|
|
|
static struct bin_attribute opal_msglog_attr = {
|
|
.attr = {.name = "msglog", .mode = 0400},
|
|
.read = opal_msglog_read
|
|
};
|
|
|
|
void __init opal_msglog_init(void)
|
|
{
|
|
u64 mcaddr;
|
|
struct memcons *mc;
|
|
|
|
if (of_property_read_u64(opal_node, "ibm,opal-memcons", &mcaddr)) {
|
|
pr_warn("OPAL: Property ibm,opal-memcons not found, no message log\n");
|
|
return;
|
|
}
|
|
|
|
mc = phys_to_virt(mcaddr);
|
|
if (!mc) {
|
|
pr_warn("OPAL: memory console address is invalid\n");
|
|
return;
|
|
}
|
|
|
|
if (be64_to_cpu(mc->magic) != MEMCONS_MAGIC) {
|
|
pr_warn("OPAL: memory console version is invalid\n");
|
|
return;
|
|
}
|
|
|
|
/* Report maximum size */
|
|
opal_msglog_attr.size = be32_to_cpu(mc->ibuf_size) +
|
|
be32_to_cpu(mc->obuf_size);
|
|
|
|
opal_memcons = mc;
|
|
}
|
|
|
|
void __init opal_msglog_sysfs_init(void)
|
|
{
|
|
if (!opal_memcons) {
|
|
pr_warn("OPAL: message log initialisation failed, not creating sysfs entry\n");
|
|
return;
|
|
}
|
|
|
|
if (sysfs_create_bin_file(opal_kobj, &opal_msglog_attr) != 0)
|
|
pr_warn("OPAL: sysfs file creation failed\n");
|
|
}
|