setup_64.c

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/*
 * 
 * Common boot and setup code.
 *
 * Copyright (C) 2001 PPC64 Team, IBM Corp
 *
 *      This program is free software; you can redistribute it and/or
 *      modify it under the terms of the GNU General Public License
 *      as published by the Free Software Foundation; either version
 *      2 of the License, or (at your option) any later version.
 */

#undef DEBUG

#include <linux/export.h>
#include <linux/string.h>
#include <linux/sched.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/reboot.h>
#include <linux/delay.h>
#include <linux/initrd.h>
#include <linux/seq_file.h>
#include <linux/ioport.h>
#include <linux/console.h>
#include <linux/utsname.h>
#include <linux/tty.h>
#include <linux/root_dev.h>
#include <linux/notifier.h>
#include <linux/cpu.h>
#include <linux/unistd.h>
#include <linux/serial.h>
#include <linux/serial_8250.h>
#include <linux/bootmem.h>
#include <linux/pci.h>
#include <linux/lockdep.h>
#include <linux/memblock.h>
#include <linux/hugetlb.h>

#include <asm/io.h>
#include <asm/kdump.h>
#include <asm/prom.h>
#include <asm/processor.h>
#include <asm/pgtable.h>
#include <asm/smp.h>
#include <asm/elf.h>
#include <asm/machdep.h>
#include <asm/paca.h>
#include <asm/time.h>
#include <asm/cputable.h>
#include <asm/sections.h>
#include <asm/btext.h>
#include <asm/nvram.h>
#include <asm/setup.h>
#include <asm/rtas.h>
#include <asm/iommu.h>
#include <asm/serial.h>
#include <asm/cache.h>
#include <asm/page.h>
#include <asm/mmu.h>
#include <asm/firmware.h>
#include <asm/xmon.h>
#include <asm/udbg.h>
#include <asm/kexec.h>
#include <asm/mmu_context.h>
#include <asm/code-patching.h>
#include <asm/kvm_ppc.h>
#include <asm/hugetlb.h>

#include "setup.h"

#ifdef DEBUG
#define DBG(fmt...) udbg_printf(fmt)
#else
#define DBG(fmt...)
#endif

int boot_cpuid = 0;
int __initdata spinning_secondaries;
u64 ppc64_pft_size;

/* Pick defaults since we might want to patch instructions
 * before we've read this from the device tree.
 */
struct ppc64_caches ppc64_caches = {
    .dline_size = 0x40,
    .log_dline_size = 6,
    .iline_size = 0x40,
    .log_iline_size = 6
};
EXPORT_SYMBOL_GPL(ppc64_caches);

/*
 * These are used in binfmt_elf.c to put aux entries on the stack
 * for each elf executable being started.
 */
int dcache_bsize;
int icache_bsize;
int ucache_bsize;

#ifdef CONFIG_SMP

static char *smt_enabled_cmdline;

/* Look for ibm,smt-enabled OF option */
static void check_smt_enabled(void)
{
    struct device_node *dn;
    const char *smt_option;

    /* Default to enabling all threads */
    smt_enabled_at_boot = threads_per_core;

    /* Allow the command line to overrule the OF option */
    if (smt_enabled_cmdline) {
        if (!strcmp(smt_enabled_cmdline, "on"))
            smt_enabled_at_boot = threads_per_core;
        else if (!strcmp(smt_enabled_cmdline, "off"))
            smt_enabled_at_boot = 0;
        else {
            long smt;
            int rc;

            rc = strict_strtol(smt_enabled_cmdline, 10, &smt);
            if (!rc)
                smt_enabled_at_boot =
                    min(threads_per_core, (int)smt);
        }
    } else {
        dn = of_find_node_by_path("/options");
        if (dn) {
            smt_option = of_get_property(dn, "ibm,smt-enabled",
                             NULL);

            if (smt_option) {
                if (!strcmp(smt_option, "on"))
                    smt_enabled_at_boot = threads_per_core;
                else if (!strcmp(smt_option, "off"))
                    smt_enabled_at_boot = 0;
            }

            of_node_put(dn);
        }
    }
}

/* Look for smt-enabled= cmdline option */
static int __init early_smt_enabled(char *p)
{
    smt_enabled_cmdline = p;
    return 0;
}
early_param("smt-enabled", early_smt_enabled);

#else
#define check_smt_enabled()
#endif /* CONFIG_SMP */

/*
 * Early initialization entry point. This is called by head.S
 * with MMU translation disabled. We rely on the "feature" of
 * the CPU that ignores the top 2 bits of the address in real
 * mode so we can access kernel globals normally provided we
 * only toy with things in the RMO region. From here, we do
 * some early parsing of the device-tree to setup out MEMBLOCK
 * data structures, and allocate & initialize the hash table
 * and segment tables so we can start running with translation
 * enabled.
 *
 * It is this function which will call the probe() callback of
 * the various platform types and copy the matching one to the
 * global ppc_md structure. Your platform can eventually do
 * some very early initializations from the probe() routine, but
 * this is not recommended, be very careful as, for example, the
 * device-tree is not accessible via normal means at this point.
 */

void __init early_setup(unsigned long dt_ptr)
{
    /* -------- printk is _NOT_ safe to use here ! ------- */

    /* Identify CPU type */
    identify_cpu(0, mfspr(SPRN_PVR));

    /* Assume we're on cpu 0 for now. Don't write to the paca yet! */
    initialise_paca(&boot_paca, 0);
    setup_paca(&boot_paca);

    /* Initialize lockdep early or else spinlocks will blow */
    lockdep_init();

    /* -------- printk is now safe to use ------- */

    /* Enable early debugging if any specified (see udbg.h) */
    udbg_early_init();

    DBG(" -> early_setup(), dt_ptr: 0x%lx\n", dt_ptr);

    /*
     * Do early initialization using the flattened device
     * tree, such as retrieving the physical memory map or
     * calculating/retrieving the hash table size.
     */
    early_init_devtree(__va(dt_ptr));

    /* Now we know the logical id of our boot cpu, setup the paca. */
    setup_paca(&paca[boot_cpuid]);

    /* Fix up paca fields required for the boot cpu */
    get_paca()->cpu_start = 1;
    /* Allow percpu accesses to "work" until we setup percpu data */
    get_paca()->data_offset = 0;

    /* Probe the machine type */
    probe_machine();

    setup_kdump_trampoline();

    DBG("Found, Initializing memory management...\n");

    /* Initialize the hash table or TLB handling */
    early_init_mmu();

    /*
     * Reserve any gigantic pages requested on the command line.
     * memblock needs to have been initialized by the time this is
     * called since this will reserve memory.
     */
    reserve_hugetlb_gpages();

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

#ifdef CONFIG_SMP
void early_setup_secondary(void)
{
    /* Mark interrupts enabled in PACA */
    get_paca()->soft_enabled = 0;

    /* Initialize the hash table or TLB handling */
    early_init_mmu_secondary();
}

#endif /* CONFIG_SMP */

#if defined(CONFIG_SMP) || defined(CONFIG_KEXEC)
void smp_release_cpus(void)
{
    unsigned long *ptr;
    int i;

    DBG(" -> smp_release_cpus()\n");

    /* All secondary cpus are spinning on a common spinloop, release them
     * all now so they can start to spin on their individual paca
     * spinloops. For non SMP kernels, the secondary cpus never get out
     * of the common spinloop.
     */

    ptr  = (unsigned long *)((unsigned long)&__secondary_hold_spinloop
            - PHYSICAL_START);
    *ptr = __pa(generic_secondary_smp_init);

    /* And wait a bit for them to catch up */
    for (i = 0; i < 100000; i++) {
        mb();
        HMT_low();
        if (spinning_secondaries == 0)
            break;
        udelay(1);
    }
    DBG("spinning_secondaries = %d\n", spinning_secondaries);

    DBG(" <- smp_release_cpus()\n");
}
#endif /* CONFIG_SMP || CONFIG_KEXEC */

/*
 * Initialize some remaining members of the ppc64_caches and systemcfg
 * structures
 * (at least until we get rid of them completely). This is mostly some
 * cache informations about the CPU that will be used by cache flush
 * routines and/or provided to userland
 */
static void __init initialize_cache_info(void)
{
    struct device_node *np;
    unsigned long num_cpus = 0;

    DBG(" -> initialize_cache_info()\n");

    for_each_node_by_type(np, "cpu") {
        num_cpus += 1;

        /*
         * We're assuming *all* of the CPUs have the same
         * d-cache and i-cache sizes... -Peter
         */
        if (num_cpus == 1) {
            const u32 *sizep, *lsizep;
            u32 size, lsize;

            size = 0;
            lsize = cur_cpu_spec->dcache_bsize;
            sizep = of_get_property(np, "d-cache-size", NULL);
            if (sizep != NULL)
                size = *sizep;
            lsizep = of_get_property(np, "d-cache-block-size",
                         NULL);
            /* fallback if block size missing */
            if (lsizep == NULL)
                lsizep = of_get_property(np,
                             "d-cache-line-size",
                             NULL);
            if (lsizep != NULL)
                lsize = *lsizep;
            if (sizep == 0 || lsizep == 0)
                DBG("Argh, can't find dcache properties ! "
                    "sizep: %p, lsizep: %p\n", sizep, lsizep);

            ppc64_caches.dsize = size;
            ppc64_caches.dline_size = lsize;
            ppc64_caches.log_dline_size = __ilog2(lsize);
            ppc64_caches.dlines_per_page = PAGE_SIZE / lsize;

            size = 0;
            lsize = cur_cpu_spec->icache_bsize;
            sizep = of_get_property(np, "i-cache-size", NULL);
            if (sizep != NULL)
                size = *sizep;
            lsizep = of_get_property(np, "i-cache-block-size",
                         NULL);
            if (lsizep == NULL)
                lsizep = of_get_property(np,
                             "i-cache-line-size",
                             NULL);
            if (lsizep != NULL)
                lsize = *lsizep;
            if (sizep == 0 || lsizep == 0)
                DBG("Argh, can't find icache properties ! "
                    "sizep: %p, lsizep: %p\n", sizep, lsizep);

            ppc64_caches.isize = size;
            ppc64_caches.iline_size = lsize;
            ppc64_caches.log_iline_size = __ilog2(lsize);
            ppc64_caches.ilines_per_page = PAGE_SIZE / lsize;
        }
    }

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


/*
 * Do some initial setup of the system.  The parameters are those which 
 * were passed in from the bootloader.
 */
void __init setup_system(void)
{
    DBG(" -> setup_system()\n");

    /* Apply the CPUs-specific and firmware specific fixups to kernel
     * text (nop out sections not relevant to this CPU or this firmware)
     */
    do_feature_fixups(cur_cpu_spec->cpu_features,
              &__start___ftr_fixup, &__stop___ftr_fixup);
    do_feature_fixups(cur_cpu_spec->mmu_features,
              &__start___mmu_ftr_fixup, &__stop___mmu_ftr_fixup);
    do_feature_fixups(powerpc_firmware_features,
              &__start___fw_ftr_fixup, &__stop___fw_ftr_fixup);
    do_lwsync_fixups(cur_cpu_spec->cpu_features,
             &__start___lwsync_fixup, &__stop___lwsync_fixup);
    do_final_fixups();

    /*
     * Unflatten the device-tree passed by prom_init or kexec
     */
    unflatten_device_tree();

    /*
     * Fill the ppc64_caches & systemcfg structures with informations
     * retrieved from the device-tree.
     */
    initialize_cache_info();

#ifdef CONFIG_PPC_RTAS
    /*
     * Initialize RTAS if available
     */
    rtas_initialize();
#endif /* CONFIG_PPC_RTAS */

    /*
     * Check if we have an initrd provided via the device-tree
     */
    check_for_initrd();

    /*
     * Do some platform specific early initializations, that includes
     * setting up the hash table pointers. It also sets up some interrupt-mapping
     * related options that will be used by finish_device_tree()
     */
    if (ppc_md.init_early)
        ppc_md.init_early();

    /*
     * We can discover serial ports now since the above did setup the
     * hash table management for us, thus ioremap works. We do that early
     * so that further code can be debugged
     */
    find_legacy_serial_ports();

    /*
     * Register early console
     */
    register_early_udbg_console();

    /*
     * Initialize xmon
     */
    xmon_setup();

    smp_setup_cpu_maps();
    check_smt_enabled();

#ifdef CONFIG_SMP
    /* Release secondary cpus out of their spinloops at 0x60 now that
     * we can map physical -> logical CPU ids
     */
    smp_release_cpus();
#endif

    printk("Starting Linux PPC64 %s\n", init_utsname()->version);

    printk("-----------------------------------------------------\n");
    printk("ppc64_pft_size                = 0x%llx\n", ppc64_pft_size);
    printk("physicalMemorySize            = 0x%llx\n", memblock_phys_mem_size());
    if (ppc64_caches.dline_size != 0x80)
        printk("ppc64_caches.dcache_line_size = 0x%x\n",
               ppc64_caches.dline_size);
    if (ppc64_caches.iline_size != 0x80)
        printk("ppc64_caches.icache_line_size = 0x%x\n",
               ppc64_caches.iline_size);
#ifdef CONFIG_PPC_STD_MMU_64
    if (htab_address)
        printk("htab_address                  = 0x%p\n", htab_address);
    printk("htab_hash_mask                = 0x%lx\n", htab_hash_mask);
#endif /* CONFIG_PPC_STD_MMU_64 */
    if (PHYSICAL_START > 0)
        printk("physical_start                = 0x%llx\n",
               (unsigned long long)PHYSICAL_START);
    printk("-----------------------------------------------------\n");

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

/* This returns the limit below which memory accesses to the linear
 * mapping are guarnateed not to cause a TLB or SLB miss. This is
 * used to allocate interrupt or emergency stacks for which our
 * exception entry path doesn't deal with being interrupted.
 */
static u64 safe_stack_limit(void)
{
#ifdef CONFIG_PPC_BOOK3E
    /* Freescale BookE bolts the entire linear mapping */
    if (mmu_has_feature(MMU_FTR_TYPE_FSL_E))
        return linear_map_top;
    /* Other BookE, we assume the first GB is bolted */
    return 1ul << 30;
#else
    /* BookS, the first segment is bolted */
    if (mmu_has_feature(MMU_FTR_1T_SEGMENT))
        return 1UL << SID_SHIFT_1T;
    return 1UL << SID_SHIFT;
#endif
}

static void __init irqstack_early_init(void)
{
    u64 limit = safe_stack_limit();
    unsigned int i;

    /*
     * Interrupt stacks must be in the first segment since we
     * cannot afford to take SLB misses on them.
     */
    for_each_possible_cpu(i) {
        softirq_ctx[i] = (struct thread_info *)
            __va(memblock_alloc_base(THREAD_SIZE,
                        THREAD_SIZE, limit));
        hardirq_ctx[i] = (struct thread_info *)
            __va(memblock_alloc_base(THREAD_SIZE,
                        THREAD_SIZE, limit));
    }
}

#ifdef CONFIG_PPC_BOOK3E
static void __init exc_lvl_early_init(void)
{
    extern unsigned int interrupt_base_book3e;
    extern unsigned int exc_debug_debug_book3e;

    unsigned int i;

    for_each_possible_cpu(i) {
        critirq_ctx[i] = (struct thread_info *)
            __va(memblock_alloc(THREAD_SIZE, THREAD_SIZE));
        dbgirq_ctx[i] = (struct thread_info *)
            __va(memblock_alloc(THREAD_SIZE, THREAD_SIZE));
        mcheckirq_ctx[i] = (struct thread_info *)
            __va(memblock_alloc(THREAD_SIZE, THREAD_SIZE));
    }

    if (cpu_has_feature(CPU_FTR_DEBUG_LVL_EXC))
        patch_branch(&interrupt_base_book3e + (0x040 / 4) + 1,
                 (unsigned long)&exc_debug_debug_book3e, 0);
}
#else
#define exc_lvl_early_init()
#endif

/*
 * Stack space used when we detect a bad kernel stack pointer, and
 * early in SMP boots before relocation is enabled.
 */
static void __init emergency_stack_init(void)
{
    u64 limit;
    unsigned int i;

    /*
     * Emergency stacks must be under 256MB, we cannot afford to take
     * SLB misses on them. The ABI also requires them to be 128-byte
     * aligned.
     *
     * Since we use these as temporary stacks during secondary CPU
     * bringup, we need to get at them in real mode. This means they
     * must also be within the RMO region.
     */
    limit = min(safe_stack_limit(), ppc64_rma_size);

    for_each_possible_cpu(i) {
        unsigned long sp;
        sp  = memblock_alloc_base(THREAD_SIZE, THREAD_SIZE, limit);
        sp += THREAD_SIZE;
        paca[i].emergency_sp = __va(sp);
    }
}

/*
 * Called into from start_kernel this initializes bootmem, which is used
 * to manage page allocation until mem_init is called.
 */
void __init setup_arch(char **cmdline_p)
{
    ppc64_boot_msg(0x12, "Setup Arch");

    *cmdline_p = cmd_line;

    /*
     * Set cache line size based on type of cpu as a default.
     * Systems with OF can look in the properties on the cpu node(s)
     * for a possibly more accurate value.
     */
    dcache_bsize = ppc64_caches.dline_size;
    icache_bsize = ppc64_caches.iline_size;

    /* reboot on panic */
    panic_timeout = 180;

    if (ppc_md.panic)
        setup_panic();

    init_mm.start_code = (unsigned long)_stext;
    init_mm.end_code = (unsigned long) _etext;
    init_mm.end_data = (unsigned long) _edata;
    init_mm.brk = klimit;
    
    irqstack_early_init();
    exc_lvl_early_init();
    emergency_stack_init();

#ifdef CONFIG_PPC_STD_MMU_64
    stabs_alloc();
#endif
    /* set up the bootmem stuff with available memory */
    do_init_bootmem();
    sparse_init();

#ifdef CONFIG_DUMMY_CONSOLE
    conswitchp = &dummy_con;
#endif

    if (ppc_md.setup_arch)
        ppc_md.setup_arch();

    paging_init();

    /* Initialize the MMU context management stuff */
    mmu_context_init();

    kvm_linear_init();

    ppc64_boot_msg(0x15, "Setup Done");
}


/* ToDo: do something useful if ppc_md is not yet setup. */
#define PPC64_LINUX_FUNCTION 0x0f000000
#define PPC64_IPL_MESSAGE 0xc0000000
#define PPC64_TERM_MESSAGE 0xb0000000

static void ppc64_do_msg(unsigned int src, const char *msg)
{
    if (ppc_md.progress) {
        char buf[128];

        sprintf(buf, "%08X\n", src);
        ppc_md.progress(buf, 0);
        snprintf(buf, 128, "%s", msg);
        ppc_md.progress(buf, 0);
    }
}

/* Print a boot progress message. */
void ppc64_boot_msg(unsigned int src, const char *msg)
{
    ppc64_do_msg(PPC64_LINUX_FUNCTION|PPC64_IPL_MESSAGE|src, msg);
    printk("[boot]%04x %s\n", src, msg);
}

#ifdef CONFIG_SMP
#define PCPU_DYN_SIZE       ()

static void * __init pcpu_fc_alloc(unsigned int cpu, size_t size, size_t align)
{
    return __alloc_bootmem_node(NODE_DATA(cpu_to_node(cpu)), size, align,
                    __pa(MAX_DMA_ADDRESS));
}

static void __init pcpu_fc_free(void *ptr, size_t size)
{
    free_bootmem(__pa(ptr), size);
}

static int pcpu_cpu_distance(unsigned int from, unsigned int to)
{
    if (cpu_to_node(from) == cpu_to_node(to))
        return LOCAL_DISTANCE;
    else
        return REMOTE_DISTANCE;
}

unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
EXPORT_SYMBOL(__per_cpu_offset);

void __init setup_per_cpu_areas(void)
{
    const size_t dyn_size = PERCPU_MODULE_RESERVE + PERCPU_DYNAMIC_RESERVE;
    size_t atom_size;
    unsigned long delta;
    unsigned int cpu;
    int rc;

    /*
     * Linear mapping is one of 4K, 1M and 16M.  For 4K, no need
     * to group units.  For larger mappings, use 1M atom which
     * should be large enough to contain a number of units.
     */
    if (mmu_linear_psize == MMU_PAGE_4K)
        atom_size = PAGE_SIZE;
    else
        atom_size = 1 << 20;

    rc = pcpu_embed_first_chunk(0, dyn_size, atom_size, pcpu_cpu_distance,
                    pcpu_fc_alloc, pcpu_fc_free);
    if (rc < 0)
        panic("cannot initialize percpu area (err=%d)", rc);

    delta = (unsigned long)pcpu_base_addr - (unsigned long)__per_cpu_start;
    for_each_possible_cpu(cpu) {
                __per_cpu_offset[cpu] = delta + pcpu_unit_offsets[cpu];
        paca[cpu].data_offset = __per_cpu_offset[cpu];
    }
}
#endif


#ifdef CONFIG_PPC_INDIRECT_IO
struct ppc_pci_io ppc_pci_io;
EXPORT_SYMBOL(ppc_pci_io);
#endif /* CONFIG_PPC_INDIRECT_IO */