path: root/arch/powerpc/kernel/dt_cpu_ftrs.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright 2017, Nicholas Piggin, IBM Corporation
 */

#define pr_fmt(fmt) "dt-cpu-ftrs: " fmt

#include <linux/export.h>
#include <linux/init.h>
#include <linux/jump_label.h>
#include <linux/libfdt.h>
#include <linux/memblock.h>
#include <linux/of_fdt.h>
#include <linux/printk.h>
#include <linux/sched.h>
#include <linux/string.h>
#include <linux/threads.h>

#include <asm/cputable.h>
#include <asm/dt_cpu_ftrs.h>
#include <asm/mce.h>
#include <asm/mmu.h>
#include <asm/setup.h>


/* Device-tree visible constants follow */
#define ISA_V3_0B       3000
#define ISA_V3_1        3100

#define USABLE_PR               (1U << 0)
#define USABLE_OS               (1U << 1)
#define USABLE_HV               (1U << 2)

#define HV_SUPPORT_HFSCR        (1U << 0)
#define OS_SUPPORT_FSCR         (1U << 0)

/* For parsing, we define all bits set as "NONE" case */
#define HV_SUPPORT_NONE		0xffffffffU
#define OS_SUPPORT_NONE		0xffffffffU

struct dt_cpu_feature {
	const char *name;
	uint32_t isa;
	uint32_t usable_privilege;
	uint32_t hv_support;
	uint32_t os_support;
	uint32_t hfscr_bit_nr;
	uint32_t fscr_bit_nr;
	uint32_t hwcap_bit_nr;
	/* fdt parsing */
	unsigned long node;
	int enabled;
	int disabled;
};

#define MMU_FTRS_HASH_BASE (MMU_FTRS_POWER8)

#define COMMON_USER_BASE	(PPC_FEATURE_32 | PPC_FEATURE_64 | \
				 PPC_FEATURE_ARCH_2_06 |\
				 PPC_FEATURE_ICACHE_SNOOP)
#define COMMON_USER2_BASE	(PPC_FEATURE2_ARCH_2_07 | \
				 PPC_FEATURE2_ISEL)
/*
 * Set up the base CPU
 */

static int hv_mode;

static struct {
	u64	lpcr;
	u64	hfscr;
	u64	fscr;
	u64	pcr;
} system_registers;

static void (*init_pmu_registers)(void);

static void __restore_cpu_cpufeatures(void)
{
	mtspr(SPRN_LPCR, system_registers.lpcr);
	if (hv_mode) {
		mtspr(SPRN_LPID, 0);
		mtspr(SPRN_AMOR, ~0);
		mtspr(SPRN_HFSCR, system_registers.hfscr);
		mtspr(SPRN_PCR, system_registers.pcr);
	}
	mtspr(SPRN_FSCR, system_registers.fscr);

	if (init_pmu_registers)
		init_pmu_registers();
}

static char dt_cpu_name[64];

static struct cpu_spec __initdata base_cpu_spec = {
	.cpu_name		= NULL,
	.cpu_features		= CPU_FTRS_DT_CPU_BASE,
	.cpu_user_features	= COMMON_USER_BASE,
	.cpu_user_features2	= COMMON_USER2_BASE,
	.mmu_features		= 0,
	.icache_bsize		= 32, /* minimum block size, fixed by */
	.dcache_bsize		= 32, /* cache info init.             */
	.num_pmcs		= 0,
	.pmc_type		= PPC_PMC_DEFAULT,
	.cpu_setup		= NULL,
	.cpu_restore		= __restore_cpu_cpufeatures,
	.machine_check_early	= NULL,
	.platform		= NULL,
};

static void __init cpufeatures_setup_cpu(void)
{
	set_cur_cpu_spec(&base_cpu_spec);

	cur_cpu_spec->pvr_mask = -1;
	cur_cpu_spec->pvr_value = mfspr(SPRN_PVR);

	/* Initialize the base environment -- clear FSCR/HFSCR.  */
	hv_mode = !!(mfmsr() & MSR_HV);
	if (hv_mode) {
		cur_cpu_spec->cpu_features |= CPU_FTR_HVMODE;
		mtspr(SPRN_HFSCR, 0);
	}
	mtspr(SPRN_FSCR, 0);
	mtspr(SPRN_PCR, PCR_MASK);

	/*
	 * LPCR does not get cleared, to match behaviour with secondaries
	 * in __restore_cpu_cpufeatures. Once the idle code is fixed, this
	 * could clear LPCR too.
	 */
}

static int __init feat_try_enable_unknown(struct dt_cpu_feature *f)
{
	if (f->hv_support == HV_SUPPORT_NONE) {
	} else if (f->hv_support & HV_SUPPORT_HFSCR) {
		u64 hfscr = mfspr(SPRN_HFSCR);
		hfscr |= 1UL << f->hfscr_bit_nr;
		mtspr(SPRN_HFSCR, hfscr);
	} else {
		/* Does not have a known recipe */
		return 0;
	}

	if (f->os_support == OS_SUPPORT_NONE) {
	} else if (f->os_support & OS_SUPPORT_FSCR) {
		u64 fscr = mfspr(SPRN_FSCR);
		fscr |= 1UL << f->fscr_bit_nr;
		mtspr(SPRN_FSCR, fscr);
	} else {
		/* Does not have a known recipe */
		return 0;
	}

	if ((f->usable_privilege & USABLE_PR) && (f->hwcap_bit_nr != -1)) {
		uint32_t word = f->hwcap_bit_nr / 32;
		uint32_t bit = f->hwcap_bit_nr % 32;

		if (word == 0)
			cur_cpu_spec->cpu_user_features |= 1U << bit;
		else if (word == 1)
			cur_cpu_spec->cpu_user_features2 |= 1U << bit;
		else
			pr_err("%s could not advertise to user (no hwcap bits)\n", f->name);
	}

	return 1;
}

static int __init feat_enable(struct dt_cpu_feature *f)
{
	if (f->hv_support != HV_SUPPORT_NONE) {
		if (f->hfscr_bit_nr != -1) {
			u64 hfscr = mfspr(SPRN_HFSCR);
			hfscr |=