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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platsmp-scu.c (2215B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * SMP support for SoCs with SCU covered by mach-shmobile
      4 *
      5 * Copyright (C) 2013  Magnus Damm
      6 */
      7#include <linux/cpu.h>
      8#include <linux/delay.h>
      9#include <linux/init.h>
     10#include <linux/io.h>
     11#include <linux/smp.h>
     12#include <asm/cacheflush.h>
     13#include <asm/smp_plat.h>
     14#include <asm/smp_scu.h>
     15#include "common.h"
     16
     17
     18static phys_addr_t shmobile_scu_base_phys;
     19static void __iomem *shmobile_scu_base;
     20
     21static int shmobile_scu_cpu_prepare(unsigned int cpu)
     22{
     23	/* For this particular CPU register SCU SMP boot vector */
     24	shmobile_smp_hook(cpu, __pa_symbol(shmobile_boot_scu),
     25			  shmobile_scu_base_phys);
     26	return 0;
     27}
     28
     29void __init shmobile_smp_scu_prepare_cpus(phys_addr_t scu_base_phys,
     30					  unsigned int max_cpus)
     31{
     32	/* install boot code shared by all CPUs */
     33	shmobile_boot_fn = __pa_symbol(shmobile_smp_boot);
     34
     35	/* enable SCU and cache coherency on booting CPU */
     36	shmobile_scu_base_phys = scu_base_phys;
     37	shmobile_scu_base = ioremap(scu_base_phys, PAGE_SIZE);
     38	scu_enable(shmobile_scu_base);
     39	scu_power_mode(shmobile_scu_base, SCU_PM_NORMAL);
     40
     41	/* Use CPU notifier for reset vector control */
     42	cpuhp_setup_state_nocalls(CPUHP_ARM_SHMOBILE_SCU_PREPARE,
     43				  "arm/shmobile-scu:prepare",
     44				  shmobile_scu_cpu_prepare, NULL);
     45}
     46
     47#ifdef CONFIG_HOTPLUG_CPU
     48void shmobile_smp_scu_cpu_die(unsigned int cpu)
     49{
     50	/* For this particular CPU deregister boot vector */
     51	shmobile_smp_hook(cpu, 0, 0);
     52
     53	dsb();
     54	flush_cache_all();
     55
     56	/* disable cache coherency */
     57	scu_power_mode(shmobile_scu_base, SCU_PM_POWEROFF);
     58
     59	/* jump to shared mach-shmobile sleep / reset code */
     60	shmobile_smp_sleep();
     61}
     62
     63static int shmobile_smp_scu_psr_core_disabled(int cpu)
     64{
     65	unsigned long mask = SCU_PM_POWEROFF << (cpu * 8);
     66
     67	if ((readl(shmobile_scu_base + 8) & mask) == mask)
     68		return 1;
     69
     70	return 0;
     71}
     72
     73int shmobile_smp_scu_cpu_kill(unsigned int cpu)
     74{
     75	int k;
     76
     77	/* this function is running on another CPU than the offline target,
     78	 * here we need wait for shutdown code in platform_cpu_die() to
     79	 * finish before asking SoC-specific code to power off the CPU core.
     80	 */
     81	for (k = 0; k < 1000; k++) {
     82		if (shmobile_smp_scu_psr_core_disabled(cpu))
     83			return 1;
     84
     85		mdelay(1);
     86	}
     87
     88	return 0;
     89}
     90#endif