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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nvram.c (2204B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 *  c 2001 PPC 64 Team, IBM Corp
      4 *
      5 * /dev/nvram driver for PPC
      6 */
      7
      8#include <linux/kernel.h>
      9#include <linux/module.h>
     10#include <linux/init.h>
     11#include <linux/spinlock.h>
     12#include <linux/uaccess.h>
     13#include <linux/of.h>
     14#include <asm/machdep.h>
     15#include <asm/rtas.h>
     16#include "chrp.h"
     17
     18static unsigned int nvram_size;
     19static unsigned char nvram_buf[4];
     20static DEFINE_SPINLOCK(nvram_lock);
     21
     22static unsigned char chrp_nvram_read_val(int addr)
     23{
     24	unsigned int done;
     25	unsigned long flags;
     26	unsigned char ret;
     27
     28	if (addr >= nvram_size) {
     29		printk(KERN_DEBUG "%s: read addr %d > nvram_size %u\n",
     30		       current->comm, addr, nvram_size);
     31		return 0xff;
     32	}
     33	spin_lock_irqsave(&nvram_lock, flags);
     34	if ((rtas_call(rtas_token("nvram-fetch"), 3, 2, &done, addr,
     35		       __pa(nvram_buf), 1) != 0) || 1 != done)
     36		ret = 0xff;
     37	else
     38		ret = nvram_buf[0];
     39	spin_unlock_irqrestore(&nvram_lock, flags);
     40
     41	return ret;
     42}
     43
     44static void chrp_nvram_write_val(int addr, unsigned char val)
     45{
     46	unsigned int done;
     47	unsigned long flags;
     48
     49	if (addr >= nvram_size) {
     50		printk(KERN_DEBUG "%s: write addr %d > nvram_size %u\n",
     51		       current->comm, addr, nvram_size);
     52		return;
     53	}
     54	spin_lock_irqsave(&nvram_lock, flags);
     55	nvram_buf[0] = val;
     56	if ((rtas_call(rtas_token("nvram-store"), 3, 2, &done, addr,
     57		       __pa(nvram_buf), 1) != 0) || 1 != done)
     58		printk(KERN_DEBUG "rtas IO error storing 0x%02x at %d", val, addr);
     59	spin_unlock_irqrestore(&nvram_lock, flags);
     60}
     61
     62static ssize_t chrp_nvram_size(void)
     63{
     64	return nvram_size;
     65}
     66
     67void __init chrp_nvram_init(void)
     68{
     69	struct device_node *nvram;
     70	const __be32 *nbytes_p;
     71	unsigned int proplen;
     72
     73	nvram = of_find_node_by_type(NULL, "nvram");
     74	if (nvram == NULL)
     75		return;
     76
     77	nbytes_p = of_get_property(nvram, "#bytes", &proplen);
     78	if (nbytes_p == NULL || proplen != sizeof(unsigned int)) {
     79		of_node_put(nvram);
     80		return;
     81	}
     82
     83	nvram_size = be32_to_cpup(nbytes_p);
     84
     85	printk(KERN_INFO "CHRP nvram contains %u bytes\n", nvram_size);
     86	of_node_put(nvram);
     87
     88	ppc_md.nvram_read_val  = chrp_nvram_read_val;
     89	ppc_md.nvram_write_val = chrp_nvram_write_val;
     90	ppc_md.nvram_size      = chrp_nvram_size;
     91
     92	return;
     93}
     94
     95MODULE_LICENSE("GPL v2");