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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leon_pmc.c (2256B)

      1// SPDX-License-Identifier: GPL-2.0
      2/* leon_pmc.c: LEON Power-down cpu_idle() handler
      3 *
      4 * Copyright (C) 2011 Daniel Hellstrom (daniel@gaisler.com) Aeroflex Gaisler AB
      5 */
      6
      7#include <linux/init.h>
      8#include <linux/pm.h>
      9
     10#include <asm/leon_amba.h>
     11#include <asm/cpu_type.h>
     12#include <asm/leon.h>
     13#include <asm/processor.h>
     14
     15/* List of Systems that need fixup instructions around power-down instruction */
     16static unsigned int pmc_leon_fixup_ids[] = {
     17	AEROFLEX_UT699,
     18	GAISLER_GR712RC,
     19	LEON4_NEXTREME1,
     20	0
     21};
     22
     23static int pmc_leon_need_fixup(void)
     24{
     25	unsigned int systemid = amba_system_id >> 16;
     26	unsigned int *id;
     27
     28	id = &pmc_leon_fixup_ids[0];
     29	while (*id != 0) {
     30		if (*id == systemid)
     31			return 1;
     32		id++;
     33	}
     34
     35	return 0;
     36}
     37
     38/*
     39 * CPU idle callback function for systems that need some extra handling
     40 * See .../arch/sparc/kernel/process.c
     41 */
     42static void pmc_leon_idle_fixup(void)
     43{
     44	/* Prepare an address to a non-cachable region. APB is always
     45	 * none-cachable. One instruction is executed after the Sleep
     46	 * instruction, we make sure to read the bus and throw away the
     47	 * value by accessing a non-cachable area, also we make sure the
     48	 * MMU does not get a TLB miss here by using the MMU BYPASS ASI.
     49	 */
     50	register unsigned int address = (unsigned int)leon3_irqctrl_regs;
     51
     52	/* Interrupts need to be enabled to not hang the CPU */
     53	raw_local_irq_enable();
     54
     55	__asm__ __volatile__ (
     56		"wr	%%g0, %%asr19\n"
     57		"lda	[%0] %1, %%g0\n"
     58		:
     59		: "r"(address), "i"(ASI_LEON_BYPASS));
     60}
     61
     62/*
     63 * CPU idle callback function
     64 * See .../arch/sparc/kernel/process.c
     65 */
     66static void pmc_leon_idle(void)
     67{
     68	/* Interrupts need to be enabled to not hang the CPU */
     69	raw_local_irq_enable();
     70
     71	/* For systems without power-down, this will be no-op */
     72	__asm__ __volatile__ ("wr	%g0, %asr19\n\t");
     73}
     74
     75/* Install LEON Power Down function */
     76static int __init leon_pmc_install(void)
     77{
     78	if (sparc_cpu_model == sparc_leon) {
     79		/* Assign power management IDLE handler */
     80		if (pmc_leon_need_fixup())
     81			sparc_idle = pmc_leon_idle_fixup;
     82		else
     83			sparc_idle = pmc_leon_idle;
     84
     85		printk(KERN_INFO "leon: power management initialized\n");
     86	}
     87
     88	return 0;
     89}
     90
     91/* This driver is not critical to the boot process, don't care
     92 * if initialized late.
     93 */
     94late_initcall(leon_pmc_install);