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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opal-nvram.c (2255B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 * PowerNV nvram code.
      4 *
      5 * Copyright 2011 IBM Corp.
      6 */
      7
      8#define DEBUG
      9
     10#include <linux/delay.h>
     11#include <linux/kernel.h>
     12#include <linux/init.h>
     13#include <linux/of.h>
     14
     15#include <asm/opal.h>
     16#include <asm/nvram.h>
     17#include <asm/machdep.h>
     18
     19static unsigned int nvram_size;
     20
     21static ssize_t opal_nvram_size(void)
     22{
     23	return nvram_size;
     24}
     25
     26static ssize_t opal_nvram_read(char *buf, size_t count, loff_t *index)
     27{
     28	s64 rc;
     29	int off;
     30
     31	if (*index >= nvram_size)
     32		return 0;
     33	off = *index;
     34	if ((off + count) > nvram_size)
     35		count = nvram_size - off;
     36	rc = opal_read_nvram(__pa(buf), count, off);
     37	if (rc != OPAL_SUCCESS)
     38		return -EIO;
     39	*index += count;
     40	return count;
     41}
     42
     43/*
     44 * This can be called in the panic path with interrupts off, so use
     45 * mdelay in that case.
     46 */
     47static ssize_t opal_nvram_write(char *buf, size_t count, loff_t *index)
     48{
     49	s64 rc = OPAL_BUSY;
     50	int off;
     51
     52	if (*index >= nvram_size)
     53		return 0;
     54	off = *index;
     55	if ((off + count) > nvram_size)
     56		count = nvram_size - off;
     57
     58	while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {
     59		rc = opal_write_nvram(__pa(buf), count, off);
     60		if (rc == OPAL_BUSY_EVENT) {
     61			if (in_interrupt() || irqs_disabled())
     62				mdelay(OPAL_BUSY_DELAY_MS);
     63			else
     64				msleep(OPAL_BUSY_DELAY_MS);
     65			opal_poll_events(NULL);
     66		} else if (rc == OPAL_BUSY) {
     67			if (in_interrupt() || irqs_disabled())
     68				mdelay(OPAL_BUSY_DELAY_MS);
     69			else
     70				msleep(OPAL_BUSY_DELAY_MS);
     71		}
     72	}
     73
     74	if (rc)
     75		return -EIO;
     76
     77	*index += count;
     78	return count;
     79}
     80
     81static int __init opal_nvram_init_log_partitions(void)
     82{
     83	/* Scan nvram for partitions */
     84	nvram_scan_partitions();
     85	nvram_init_oops_partition(0);
     86	return 0;
     87}
     88machine_arch_initcall(powernv, opal_nvram_init_log_partitions);
     89
     90void __init opal_nvram_init(void)
     91{
     92	struct device_node *np;
     93	const __be32 *nbytes_p;
     94
     95	np = of_find_compatible_node(NULL, NULL, "ibm,opal-nvram");
     96	if (np == NULL)
     97		return;
     98
     99	nbytes_p = of_get_property(np, "#bytes", NULL);
    100	if (!nbytes_p) {
    101		of_node_put(np);
    102		return;
    103	}
    104	nvram_size = be32_to_cpup(nbytes_p);
    105
    106	pr_info("OPAL nvram setup, %u bytes\n", nvram_size);
    107	of_node_put(np);
    108
    109	ppc_md.nvram_read = opal_nvram_read;
    110	ppc_md.nvram_write = opal_nvram_write;
    111	ppc_md.nvram_size = opal_nvram_size;
    112}
    113