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

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Procedures for creating, accessing and interpreting the device tree.
 *
 * Paul Mackerras	August 1996.
 * Copyright (C) 1996-2005 Paul Mackerras.
 * 
 *  Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner.
 *    {engebret|bergner}@us.ibm.com 
 */

#undef DEBUG

#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/threads.h>
#include <linux/spinlock.h>
#include <linux/types.h>
#include <linux/pci.h>
#include <linux/delay.h>
#include <linux/initrd.h>
#include <linux/bitops.h>
#include <linux/export.h>
#include <linux/kexec.h>
#include <linux/irq.h>
#include <linux/memblock.h>
#include <linux/of.h>
#include <linux/of_fdt.h>
#include <linux/libfdt.h>
#include <linux/cpu.h>
#include <linux/pgtable.h>
#include <linux/seq_buf.h>

#include <asm/rtas.h>
#include <asm/page.h>
#include <asm/processor.h>
#include <asm/irq.h>
#include <asm/io.h>
#include <asm/kdump.h>
#include <asm/smp.h>
#include <asm/mmu.h>
#include <asm/paca.h>
#include <asm/powernv.h>
#include <asm/iommu.h>
#include <asm/btext.h>
#include <asm/sections.h>
#include <asm/setup.h>
#include <asm/pci-bridge.h>
#include <asm/kexec.h>
#include <asm/opal.h>
#include <asm/fadump.h>
#include <asm/epapr_hcalls.h>
#include <asm/firmware.h>
#include <asm/dt_cpu_ftrs.h>
#include <asm/drmem.h>
#include <asm/ultravisor.h>
#include <asm/prom.h>
#include <asm/plpks.h>

#include <mm/mmu_decl.h>

#ifdef DEBUG
#define DBG(fmt...) printk(KERN_ERR fmt)
#else
#define DBG(fmt...)
#endif

int *chip_id_lookup_table;

#ifdef CONFIG_PPC64
int __initdata iommu_is_off;
int __initdata iommu_force_on;
unsigned long tce_alloc_start, tce_alloc_end;
u64 ppc64_rma_size;
unsigned int boot_cpu_node_count __ro_after_init;
#endif
static phys_addr_t first_memblock_size;
static int __initdata boot_cpu_count;

static int __init early_parse_mem(char *p)
{
	if (!p)
		return 1;

	memory_limit = PAGE_ALIGN(memparse(p, &p));
	DBG("memory limit = 0x%llx\n", memory_limit);

	return 0;
}
early_param("mem", early_parse_mem);

/*
 * overlaps_initrd - check for overlap with page aligned extension of
 * initrd.
 */
static inline int overlaps_initrd(unsigned long start, unsigned long size)
{
#ifdef CONFIG_BLK_DEV_INITRD
	if (!initrd_start)
		return 0;

	return	(start + size) > ALIGN_DOWN(initrd_start, PAGE_SIZE) &&
			start <= ALIGN(initrd_end, PAGE_SIZE);
#else
	return 0;
#endif
}

/**
 * move_device_tree - move tree to an unused area, if needed.
 *
 * The device tree may be allocated beyond our memory limit, or inside the
 * crash kernel region for kdump, or within the page aligned range of initrd.
 * If so, move it out of the way.
 */
static void __init move_device_tree(void)
{
	unsigned long start, size;
	void *p;

	DBG("-> move_device_tree\n");

	start = __pa(initial_boot_params);
	size = fdt_totalsize(initial_boot_params);

	if ((memory_limit && (start + size) > PHYSICAL_START + memory_limit) ||
	    !memblock_is_memory(start + size - 1) ||
	    overlaps_crashkernel(start, size) || overlaps_initrd(start, size)) {
		p = memblock_alloc_raw(size, PAGE_SIZE);
		if (!p)
			panic("Failed to allocate %lu bytes to move device tree\n",
			      size);
		memcpy(p, initial_boot_params, size);
		initial_boot_params = p;
		DBG("Moved device tree to 0x%px\n", p);
	}

	DBG("<- move_device_tree\n");
}

/*
 * ibm,pa/pi-features is a per-cpu property that contains a string of
 * attribute descriptors, each of which has a 2 byte header plus up
 * to 254 bytes worth of processor attribute bits.  First header
 * byte specifies the number of bytes following the header.
 * Second header byte is an "attribute-specifier" type, of which
 * zero is the only currently-defined value.
 * Implementation:  Pass in the byte and bit offset for the feature
 * that we are interested in.  The function will return -1 if the
 * pa-features property is missing, or a 1/0 to indicate if the feature
 * is supported/not supported.  Note that the bit numbers are
 * big-endian to match the definition in PAPR.
 */
struct ibm_feature {
	unsigned long	cpu_features;	/* CPU_FTR_xxx bit */
	unsigned long	mmu_features;	/* MMU_FTR_xxx bit */
	unsigned int	cpu_user_ftrs;	/* PPC_FEATURE_xxx bit */
	unsigned int	cpu_user_ftrs2;	/* PPC_FEATURE2_xxx bit */
	unsigned char	pabyte;		/* byte number in ibm,pa/pi-features */
	unsigned char	pabit;		/* bit number (big-endian) */
	unsigned char	invert;		/* if 1, pa bit set => clear feature */
};

static struct ibm_feature ibm_pa_features[] __initdata = {
	{ .pabyte = 0,  .pabit = 0, .cpu_user_ftrs = PPC_FEATURE_HAS_MMU },
	{ .pabyte = 0,  .pabit = 1, .cpu_user_ftrs = PPC_FEATURE_HAS_FPU },
	{ .pabyte = 0,  .pabit = 3, .cpu_features  = CPU_FTR_CTRL },
	{ .pabyte =