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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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b14726c51c
A lot of the code in platforms/powernv is using non-machine initcalls. That means if a kernel built with powernv support runs on another platform, for example pseries, the initcalls will still run. That is usually OK, because the initcalls will check for something in the device tree or elsewhere before doing anything, so on other platforms they will usually just return. But it's fishy for powernv code to be running on other platforms, so switch them all to be machine initcalls. If we want any of them to run on other platforms in future they should move to sysdev. Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
127 lines
2.5 KiB
C
127 lines
2.5 KiB
C
/*
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* Copyright 2013, Michael Ellerman, IBM Corporation.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#define pr_fmt(fmt) "powernv-rng: " fmt
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#include <linux/kernel.h>
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#include <linux/of.h>
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#include <linux/of_address.h>
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#include <linux/of_platform.h>
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#include <linux/slab.h>
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#include <linux/smp.h>
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#include <asm/archrandom.h>
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#include <asm/io.h>
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#include <asm/prom.h>
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#include <asm/machdep.h>
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#include <asm/smp.h>
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struct powernv_rng {
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void __iomem *regs;
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unsigned long mask;
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};
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static DEFINE_PER_CPU(struct powernv_rng *, powernv_rng);
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static unsigned long rng_whiten(struct powernv_rng *rng, unsigned long val)
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{
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unsigned long parity;
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/* Calculate the parity of the value */
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asm ("popcntd %0,%1" : "=r" (parity) : "r" (val));
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/* xor our value with the previous mask */
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val ^= rng->mask;
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/* update the mask based on the parity of this value */
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rng->mask = (rng->mask << 1) | (parity & 1);
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return val;
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}
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int powernv_get_random_long(unsigned long *v)
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{
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struct powernv_rng *rng;
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rng = get_cpu_var(powernv_rng);
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*v = rng_whiten(rng, in_be64(rng->regs));
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put_cpu_var(rng);
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return 1;
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}
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EXPORT_SYMBOL_GPL(powernv_get_random_long);
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static __init void rng_init_per_cpu(struct powernv_rng *rng,
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struct device_node *dn)
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{
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int chip_id, cpu;
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chip_id = of_get_ibm_chip_id(dn);
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if (chip_id == -1)
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pr_warn("No ibm,chip-id found for %s.\n", dn->full_name);
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for_each_possible_cpu(cpu) {
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if (per_cpu(powernv_rng, cpu) == NULL ||
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cpu_to_chip_id(cpu) == chip_id) {
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per_cpu(powernv_rng, cpu) = rng;
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}
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}
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}
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static __init int rng_create(struct device_node *dn)
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{
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struct powernv_rng *rng;
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unsigned long val;
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rng = kzalloc(sizeof(*rng), GFP_KERNEL);
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if (!rng)
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return -ENOMEM;
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rng->regs = of_iomap(dn, 0);
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if (!rng->regs) {
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kfree(rng);
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return -ENXIO;
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}
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val = in_be64(rng->regs);
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rng->mask = val;
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rng_init_per_cpu(rng, dn);
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pr_info_once("Registering arch random hook.\n");
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ppc_md.get_random_long = powernv_get_random_long;
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return 0;
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}
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static __init int rng_init(void)
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{
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struct device_node *dn;
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int rc;
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for_each_compatible_node(dn, NULL, "ibm,power-rng") {
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rc = rng_create(dn);
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if (rc) {
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pr_err("Failed creating rng for %s (%d).\n",
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dn->full_name, rc);
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continue;
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}
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/* Create devices for hwrng driver */
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of_platform_device_create(dn, NULL, NULL);
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}
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return 0;
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}
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machine_subsys_initcall(powernv, rng_init);
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