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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devices.c (3119B)

      1// SPDX-License-Identifier: GPL-2.0
      2/* devices.c: Initial scan of the prom device tree for important
      3 *	      Sparc device nodes which we need to find.
      4 *
      5 * This is based on the sparc64 version, but sun4m doesn't always use
      6 * the hardware MIDs, so be careful.
      7 *
      8 * Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
      9 */
     10
     11#include <linux/kernel.h>
     12#include <linux/threads.h>
     13#include <linux/string.h>
     14#include <linux/init.h>
     15#include <linux/errno.h>
     16
     17#include <asm/page.h>
     18#include <asm/oplib.h>
     19#include <asm/prom.h>
     20#include <asm/smp.h>
     21#include <asm/cpudata.h>
     22#include <asm/cpu_type.h>
     23#include <asm/setup.h>
     24
     25#include "kernel.h"
     26
     27static char *cpu_mid_prop(void)
     28{
     29	if (sparc_cpu_model == sun4d)
     30		return "cpu-id";
     31	return "mid";
     32}
     33
     34static int check_cpu_node(phandle nd, int *cur_inst,
     35		int (*compare)(phandle, int, void *), void *compare_arg,
     36		phandle *prom_node, int *mid)
     37{
     38	if (!compare(nd, *cur_inst, compare_arg)) {
     39		if (prom_node)
     40			*prom_node = nd;
     41		if (mid) {
     42			*mid = prom_getintdefault(nd, cpu_mid_prop(), 0);
     43			if (sparc_cpu_model == sun4m)
     44				*mid &= 3;
     45		}
     46		return 0;
     47	}
     48
     49	(*cur_inst)++;
     50
     51	return -ENODEV;
     52}
     53
     54static int __cpu_find_by(int (*compare)(phandle, int, void *),
     55		void *compare_arg, phandle *prom_node, int *mid)
     56{
     57	struct device_node *dp;
     58	int cur_inst;
     59
     60	cur_inst = 0;
     61	for_each_node_by_type(dp, "cpu") {
     62		int err = check_cpu_node(dp->phandle, &cur_inst,
     63					 compare, compare_arg,
     64					 prom_node, mid);
     65		if (!err) {
     66			of_node_put(dp);
     67			return 0;
     68		}
     69	}
     70
     71	return -ENODEV;
     72}
     73
     74static int cpu_instance_compare(phandle nd, int instance, void *_arg)
     75{
     76	int desired_instance = (int) _arg;
     77
     78	if (instance == desired_instance)
     79		return 0;
     80	return -ENODEV;
     81}
     82
     83int cpu_find_by_instance(int instance, phandle *prom_node, int *mid)
     84{
     85	return __cpu_find_by(cpu_instance_compare, (void *)instance,
     86			     prom_node, mid);
     87}
     88
     89static int cpu_mid_compare(phandle nd, int instance, void *_arg)
     90{
     91	int desired_mid = (int) _arg;
     92	int this_mid;
     93
     94	this_mid = prom_getintdefault(nd, cpu_mid_prop(), 0);
     95	if (this_mid == desired_mid
     96	    || (sparc_cpu_model == sun4m && (this_mid & 3) == desired_mid))
     97		return 0;
     98	return -ENODEV;
     99}
    100
    101int cpu_find_by_mid(int mid, phandle *prom_node)
    102{
    103	return __cpu_find_by(cpu_mid_compare, (void *)mid,
    104			     prom_node, NULL);
    105}
    106
    107/* sun4m uses truncated mids since we base the cpuid on the ttable/irqset
    108 * address (0-3).  This gives us the true hardware mid, which might have
    109 * some other bits set.  On 4d hardware and software mids are the same.
    110 */
    111int cpu_get_hwmid(phandle prom_node)
    112{
    113	return prom_getintdefault(prom_node, cpu_mid_prop(), -ENODEV);
    114}
    115
    116void __init device_scan(void)
    117{
    118	printk(KERN_NOTICE "Booting Linux...\n");
    119
    120#ifndef CONFIG_SMP
    121	{
    122		phandle cpu_node;
    123		int err;
    124		err = cpu_find_by_instance(0, &cpu_node, NULL);
    125		if (err) {
    126			/* Probably a sun4e, Sun is trying to trick us ;-) */
    127			prom_printf("No cpu nodes, cannot continue\n");
    128			prom_halt();
    129		}
    130		cpu_data(0).clock_tick = prom_getintdefault(cpu_node,
    131							    "clock-frequency",
    132							    0);
    133	}
    134#endif /* !CONFIG_SMP */
    135
    136	auxio_probe();
    137	auxio_power_probe();
    138}