drm/panthor: Don't add write fences to the shared BOs

[drm/drm-misc.git] / arch / parisc / kernel / cache.c

/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 1999-2006 Helge Deller <deller@gmx.de> (07-13-1999)
 * Copyright (C) 1999 SuSE GmbH Nuernberg
 * Copyright (C) 2000 Philipp Rumpf (prumpf@tux.org)
 *
 * Cache and TLB management
 *
 */
 
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/seq_file.h>
#include <linux/pagemap.h>
#include <linux/sched.h>
#include <linux/sched/mm.h>
#include <linux/syscalls.h>
#include <linux/vmalloc.h>
#include <asm/pdc.h>
#include <asm/cache.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include <asm/page.h>
#include <asm/processor.h>
#include <asm/sections.h>
#include <asm/shmparam.h>
#include <asm/mmu_context.h>
#include <asm/cachectl.h>

#define PTR_PAGE_ALIGN_DOWN(addr) PTR_ALIGN_DOWN(addr, PAGE_SIZE)

/*
 * When nonzero, use _PAGE_ACCESSED bit to try to reduce the number
 * of page flushes done flush_cache_page_if_present. There are some
 * pros and cons in using this option. It may increase the risk of
 * random segmentation faults.
 */
#define CONFIG_FLUSH_PAGE_ACCESSED      0

int split_tlb __ro_after_init;
int dcache_stride __ro_after_init;
int icache_stride __ro_after_init;
EXPORT_SYMBOL(dcache_stride);

/* Internal implementation in arch/parisc/kernel/pacache.S */
void flush_dcache_page_asm(unsigned long phys_addr, unsigned long vaddr);
EXPORT_SYMBOL(flush_dcache_page_asm);
void purge_dcache_page_asm(unsigned long phys_addr, unsigned long vaddr);
void flush_icache_page_asm(unsigned long phys_addr, unsigned long vaddr);
void flush_data_cache_local(void *);  /* flushes local data-cache only */
void flush_instruction_cache_local(void); /* flushes local code-cache only */

static void flush_kernel_dcache_page_addr(const void *addr);

/* On some machines (i.e., ones with the Merced bus), there can be
 * only a single PxTLB broadcast at a time; this must be guaranteed
 * by software. We need a spinlock around all TLB flushes to ensure
 * this.
 */
DEFINE_SPINLOCK(pa_tlb_flush_lock);

#if defined(CONFIG_64BIT) && defined(CONFIG_SMP)
int pa_serialize_tlb_flushes __ro_after_init;
#endif

struct pdc_cache_info cache_info __ro_after_init;
#ifndef CONFIG_PA20
struct pdc_btlb_info btlb_info;
#endif

DEFINE_STATIC_KEY_TRUE(parisc_has_cache);
DEFINE_STATIC_KEY_TRUE(parisc_has_dcache);
DEFINE_STATIC_KEY_TRUE(parisc_has_icache);

static void cache_flush_local_cpu(void *dummy)
{
        if (static_branch_likely(&parisc_has_icache))
                flush_instruction_cache_local();
        if (static_branch_likely(&parisc_has_dcache))
                flush_data_cache_local(NULL);
}

void flush_cache_all_local(void)
{
        cache_flush_local_cpu(NULL);
}

void flush_cache_all(void)
{
        if (static_branch_likely(&parisc_has_cache))
                on_each_cpu(cache_flush_local_cpu, NULL, 1);
}

static inline void flush_data_cache(void)
{
        if (static_branch_likely(&parisc_has_dcache))
                on_each_cpu(flush_data_cache_local, NULL, 1);
}


/* Kernel virtual address of pfn.  */
#define pfn_va(pfn)     __va(PFN_PHYS(pfn))

void __update_cache(pte_t pte)
{
        unsigned long pfn = pte_pfn(pte);
        struct folio *folio;
        unsigned int nr;

        /* We don't have pte special.  As a result, we can be called with
           an invalid pfn and we don't need to flush the kernel dcache page.
           This occurs with FireGL card in C8000.  */
        if (!pfn_valid(pfn))
                return;

        folio = page_folio(pfn_to_page(pfn));
        pfn = folio_pfn(folio);
        nr = folio_nr_pages(folio);
        if (folio_flush_mapping(folio) &&
            test_bit(PG_dcache_dirty, &folio->flags)) {
                while (nr--)
                        flush_kernel_dcache_page_addr(pfn_va(pfn + nr));
                clear_bit(PG_dcache_dirty, &folio->flags);
        } else if (parisc_requires_coherency())
                while (nr--)
                        flush_kernel_dcache_page_addr(pfn_va(pfn + nr));
}

void
show_cache_info(struct seq_file *m)
{
        char buf[32];

        seq_printf(m, "I-cache\t\t: %ld KB\n", 
                cache_info.ic_size/1024 );
        if (cache_info.dc_loop != 1)
                snprintf(buf, 32, "%lu-way associative", cache_info.dc_loop);
        seq_printf(m, "D-cache\t\t: %ld KB (%s%s, %s, alias=%d)\n",
                cache_info.dc_size/1024,
                (cache_info.dc_conf.cc_wt ? "WT":"WB"),
                (cache_info.dc_conf.cc_sh ? ", shared I/D":""),
                ((cache_info.dc_loop == 1) ? "direct mapped" : buf),
                cache_info.dc_conf.cc_alias
        );
        seq_printf(m, "ITLB entries\t: %ld\n" "DTLB entries\t: %ld%s\n",
                cache_info.it_size,
                cache_info.dt_size,
                cache_info.dt_conf.tc_sh ? " - shared with ITLB":""
        );
                
#ifndef CONFIG_PA20
        /* BTLB - Block TLB */
        if (btlb_info.max_size==0) {
                seq_printf(m, "BTLB\t\t: not supported\n" );
        } else {
                seq_printf(m, 
                "BTLB fixed\t: max. %d pages, pagesize=%d (%dMB)\n"
                "BTLB fix-entr.\t: %d instruction, %d data (%d combined)\n"
                "BTLB var-entr.\t: %d instruction, %d data (%d combined)\n",
                btlb_info.max_size, (int)4096,
                btlb_info.max_size>>8,
                btlb_info.fixed_range_info.num_i,
                btlb_info.fixed_range_info.num_d,
                btlb_info.fixed_range_info.num_comb, 
                btlb_info.variable_range_info.num_i,
                btlb_info.variable_range_info.num_d,
                btlb_info.variable_range_info.num_comb
                );
        }
#endif
}

void __init 
parisc_cache_init(void)
{
        if (pdc_cache_info(&cache_info) < 0)
                panic("parisc_cache_init: pdc_cache_info failed");

#if 0
        printk("ic_size %lx dc_size %lx it_size %lx\n",
                cache_info.ic_size,
                cache_info.dc_size,
                cache_info.it_size);

        printk("DC  base 0x%lx stride 0x%lx count 0x%lx loop 0x%lx\n",
                cache_info.dc_base,
                cache_info.dc_stride,
                cache_info.dc_count,
                cache_info.dc_loop);

        printk("dc_conf = 0x%lx  alias %d blk %d line %d shift %d\n",
                *(unsigned long *) (&cache_info.dc_conf),
                cache_info.dc_conf.cc_alias,
                cache_info.dc_conf.cc_block,
                cache_info.dc_conf.cc_line,
                cache_info.dc_conf.cc_shift);
        printk("        wt %d sh %d cst %d hv %d\n",
                cache_info.dc_conf.cc_wt,
                cache_info.dc_conf.cc_sh,
                cache_info.dc_conf.cc_cst,
                cache_info.dc_conf.cc_hv);

        printk("IC  base 0x%lx stride 0x%lx count 0x%lx loop 0x%lx\n",
                cache_info.ic_base,
                cache_info.ic_stride,
                cache_info.ic_count,
                cache_info.ic_loop);

        printk("IT  base 0x%lx stride 0x%lx count 0x%lx loop 0x%lx off_base 0x%lx off_stride 0x%lx off_count 0x%lx\n",
                cache_info.it_sp_base,
                cache_info.it_sp_stride,
                cache_info.it_sp_count,
                cache_info.it_loop,
                cache_info.it_off_base,
                cache_info.it_off_stride,
                cache_info.it_off_count);

        printk("DT  base 0x%lx stride 0x%lx count 0x%lx loop 0x%lx off_base 0x%lx off_stride 0x%lx off_count 0x%lx\n",
                cache_info.dt_sp_base,
                cache_info.dt_sp_stride,
                cache_info.dt_sp_count,
                cache_info.dt_loop,
                cache_info.dt_off_base,
                cache_info.dt_off_stride,
                cache_info.dt_off_count);

        printk("ic_conf = 0x%lx  alias %d blk %d line %d shift %d\n",
                *(unsigned long *) (&cache_info.ic_conf),
                cache_info.ic_conf.cc_alias,
                cache_info.ic_conf.cc_block,
                cache_info.ic_conf.cc_line,
                cache_info.ic_conf.cc_shift);
        printk("        wt %d sh %d cst %d hv %d\n",
                cache_info.ic_conf.cc_wt,
                cache_info.ic_conf.cc_sh,
                cache_info.ic_conf.cc_cst,
                cache_info.ic_conf.cc_hv);

        printk("D-TLB conf: sh %d page %d cst %d aid %d sr %d\n",
                cache_info.dt_conf.tc_sh,
                cache_info.dt_conf.tc_page,
                cache_info.dt_conf.tc_cst,
                cache_info.dt_conf.tc_aid,
                cache_info.dt_conf.tc_sr);

        printk("I-TLB conf: sh %d page %d cst %d aid %d sr %d\n",
                cache_info.it_conf.tc_sh,
                cache_info.it_conf.tc_page,
                cache_info.it_conf.tc_cst,
                cache_info.it_conf.tc_aid,
                cache_info.it_conf.tc_sr);
#endif

        split_tlb = 0;
        if (cache_info.dt_conf.tc_sh == 0 || cache_info.dt_conf.tc_sh == 2) {
                if (cache_info.dt_conf.tc_sh == 2)
                        printk(KERN_WARNING "Unexpected TLB configuration. "
                        "Will flush I/D separately (could be optimized).\n");

                split_tlb = 1;
        }

        /* "New and Improved" version from Jim Hull 
         *      (1 << (cc_block-1)) * (cc_line << (4 + cnf.cc_shift))
         * The following CAFL_STRIDE is an optimized version, see
         * http://lists.parisc-linux.org/pipermail/parisc-linux/2004-June/023625.html
         * http://lists.parisc-linux.org/pipermail/parisc-linux/2004-June/023671.html
         */
#define CAFL_STRIDE(cnf) (cnf.cc_line << (3 + cnf.cc_block + cnf.cc_shift))
        dcache_stride = CAFL_STRIDE(cache_info.dc_conf);
        icache_stride = CAFL_STRIDE(cache_info.ic_conf);
#undef CAFL_STRIDE

        /* stride needs to be non-zero, otherwise cache flushes will not work */
        WARN_ON(cache_info.dc_size && dcache_stride == 0);
        WARN_ON(cache_info.ic_size && icache_stride == 0);

        if ((boot_cpu_data.pdc.capabilities & PDC_MODEL_NVA_MASK) ==
                                                PDC_MODEL_NVA_UNSUPPORTED) {
                printk(KERN_WARNING "parisc_cache_init: Only equivalent aliasing supported!\n");
#if 0
                panic("SMP kernel required to avoid non-equivalent aliasing");
#endif
        }
}

void disable_sr_hashing(void)
{
        int srhash_type, retval;
        unsigned long space_bits;

        switch (boot_cpu_data.cpu_type) {
        case pcx: /* We shouldn't get this far.  setup.c should prevent it. */
                BUG();
                return;

        case pcxs:
        case pcxt:
        case pcxt_:
                srhash_type = SRHASH_PCXST;
                break;

        case pcxl:
                srhash_type = SRHASH_PCXL;
                break;

        case pcxl2: /* pcxl2 doesn't support space register hashing */
                return;

        default: /* Currently all PA2.0 machines use the same ins. sequence */
                srhash_type = SRHASH_PA20;
                break;
        }

        disable_sr_hashing_asm(srhash_type);

        retval = pdc_spaceid_bits(&space_bits);
        /* If this procedure isn't implemented, don't panic. */
        if (retval < 0 && retval != PDC_BAD_OPTION)
                panic("pdc_spaceid_bits call failed.\n");
        if (space_bits != 0)
                panic("SpaceID hashing is still on!\n");
}

static inline void
__flush_cache_page(struct vm_area_struct *vma, unsigned long vmaddr,
                   unsigned long physaddr)
{
        if (!static_branch_likely(&parisc_has_cache))
                return;

        /*
         * The TLB is the engine of coherence on parisc.  The CPU is
         * entitled to speculate any page with a TLB mapping, so here
         * we kill the mapping then flush the page along a special flush
         * only alias mapping. This guarantees that the page is no-longer
         * in the cache for any process and nor may it be speculatively
         * read in (until the user or kernel specifically accesses it,
         * of course).
         */
        flush_tlb_page(vma, vmaddr);

        preempt_disable();
        flush_dcache_page_asm(physaddr, vmaddr);
        if (vma->vm_flags & VM_EXEC)
                flush_icache_page_asm(physaddr, vmaddr);
        preempt_enable();
}

static void flush_kernel_dcache_page_addr(const void *addr)
{
        unsigned long vaddr = (unsigned long)addr;
        unsigned long flags;

        /* Purge TLB entry to remove translation on all CPUs */
        purge_tlb_start(flags);
        pdtlb(SR_KERNEL, addr);
        purge_tlb_end(flags);

        /* Use tmpalias flush to prevent data cache move-in */
        preempt_disable();
        flush_dcache_page_asm(__pa(vaddr), vaddr);
        preempt_enable();
}

static void flush_kernel_icache_page_addr(const void *addr)
{
        unsigned long vaddr = (unsigned long)addr;
        unsigned long flags;

        /* Purge TLB entry to remove translation on all CPUs */
        purge_tlb_start(flags);
        pdtlb(SR_KERNEL, addr);
        purge_tlb_end(flags);

        /* Use tmpalias flush to prevent instruction cache move-in */
        preempt_disable();
        flush_icache_page_asm(__pa(vaddr), vaddr);
        preempt_enable();
}

void kunmap_flush_on_unmap(const void *addr)
{
        flush_kernel_dcache_page_addr(addr);
}
EXPORT_SYMBOL(kunmap_flush_on_unmap);

void flush_icache_pages(struct vm_area_struct *vma, struct page *page,
                unsigned int nr)
{
        void *kaddr = page_address(page);

        for (;;) {
                flush_kernel_dcache_page_addr(kaddr);
                flush_kernel_icache_page_addr(kaddr);
                if (--nr == 0)
                        break;
                kaddr += PAGE_SIZE;
        }
}

/*
 * Walk page directory for MM to find PTEP pointer for address ADDR.
 */
static inline pte_t *get_ptep(struct mm_struct *mm, unsigned long addr)
{
        pte_t *ptep = NULL;
        pgd_t *pgd = mm->pgd;
        p4d_t *p4d;
        pud_t *pud;
        pmd_t *pmd;

        if (!pgd_none(*pgd)) {
                p4d = p4d_offset(pgd, addr);
                if (!p4d_none(*p4d)) {
                        pud = pud_offset(p4d, addr);
                        if (!pud_none(*pud)) {
                                pmd = pmd_offset(pud, addr);
                                if (!pmd_none(*pmd))
                                        ptep = pte_offset_map(pmd, addr);
                        }
                }
        }
        return ptep;
}

static inline bool pte_needs_flush(pte_t pte)
{
        return (pte_val(pte) & (_PAGE_PRESENT | _PAGE_ACCESSED | _PAGE_NO_CACHE))
                == (_PAGE_PRESENT | _PAGE_ACCESSED);
}

/*
 * Return user physical address. Returns 0 if page is not present.
 */
static inline unsigned long get_upa(struct mm_struct *mm, unsigned long addr)
{
        unsigned long flags, space, pgd, prot, pa;
#ifdef CONFIG_TLB_PTLOCK
        unsigned long pgd_lock;
#endif

        /* Save context */
        local_irq_save(flags);
        prot = mfctl(8);
        space = mfsp(SR_USER);
        pgd = mfctl(25);
#ifdef CONFIG_TLB_PTLOCK
        pgd_lock = mfctl(28);
#endif

        /* Set context for lpa_user */
        switch_mm_irqs_off(NULL, mm, NULL);
        pa = lpa_user(addr);

        /* Restore previous context */
#ifdef CONFIG_TLB_PTLOCK
        mtctl(pgd_lock, 28);
#endif
        mtctl(pgd, 25);
        mtsp(space, SR_USER);
        mtctl(prot, 8);
        local_irq_restore(flags);

        return pa;
}

void flush_dcache_folio(struct folio *folio)
{
        struct address_space *mapping = folio_flush_mapping(folio);
        struct vm_area_struct *vma;
        unsigned long addr, old_addr = 0;
        void *kaddr;
        unsigned long count = 0;
        unsigned long i, nr, flags;
        pgoff_t pgoff;

        if (mapping && !mapping_mapped(mapping)) {
                set_bit(PG_dcache_dirty, &folio->flags);
                return;
        }

        nr = folio_nr_pages(folio);
        kaddr = folio_address(folio);
        for (i = 0; i < nr; i++)
                flush_kernel_dcache_page_addr(kaddr + i * PAGE_SIZE);

        if (!mapping)
                return;

        pgoff = folio->index;

        /*
         * We have carefully arranged in arch_get_unmapped_area() that
         * *any* mappings of a file are always congruently mapped (whether
         * declared as MAP_PRIVATE or MAP_SHARED), so we only need
         * to flush one address here for them all to become coherent
         * on machines that support equivalent aliasing
         */
        flush_dcache_mmap_lock_irqsave(mapping, flags);
        vma_interval_tree_foreach(vma, &mapping->i_mmap, pgoff, pgoff + nr - 1) {
                unsigned long offset = pgoff - vma->vm_pgoff;
                unsigned long pfn = folio_pfn(folio);

                addr = vma->vm_start;
                nr = folio_nr_pages(folio);
                if (offset > -nr) {
                        pfn -= offset;
                        nr += offset;
                } else {
                        addr += offset * PAGE_SIZE;
                }
                if (addr + nr * PAGE_SIZE > vma->vm_end)
                        nr = (vma->vm_end - addr) / PAGE_SIZE;

                if (old_addr == 0 || (old_addr & (SHM_COLOUR - 1))
                                        != (addr & (SHM_COLOUR - 1))) {
                        for (i = 0; i < nr; i++)
                                __flush_cache_page(vma,
                                        addr + i * PAGE_SIZE,
                                        (pfn + i) * PAGE_SIZE);
                        /*
                         * Software is allowed to have any number
                         * of private mappings to a page.
                         */
                        if (!(vma->vm_flags & VM_SHARED))
                                continue;
                        if (old_addr)
                                pr_err("INEQUIVALENT ALIASES 0x%lx and 0x%lx in file %pD\n",
                                        old_addr, addr, vma->vm_file);
                        if (nr == folio_nr_pages(folio))
                                old_addr = addr;
                }
                WARN_ON(++count == 4096);
        }
        flush_dcache_mmap_unlock_irqrestore(mapping, flags);
}
EXPORT_SYMBOL(flush_dcache_folio);

/* Defined in arch/parisc/kernel/pacache.S */
EXPORT_SYMBOL(flush_kernel_dcache_range_asm);
EXPORT_SYMBOL(flush_kernel_icache_range_asm);

#define FLUSH_THRESHOLD 0x80000 /* 0.5MB */
static unsigned long parisc_cache_flush_threshold __ro_after_init = FLUSH_THRESHOLD;

#define FLUSH_TLB_THRESHOLD (16*1024) /* 16 KiB minimum TLB threshold */
static unsigned long parisc_tlb_flush_threshold __ro_after_init = ~0UL;

void __init parisc_setup_cache_timing(void)
{
        unsigned long rangetime, alltime;
        unsigned long size;
        unsigned long threshold, threshold2;

        alltime = mfctl(16);
        flush_data_cache();
        alltime = mfctl(16) - alltime;

        size = (unsigned long)(_end - _text);
        rangetime = mfctl(16);
        flush_kernel_dcache_range((unsigned long)_text, size);
        rangetime = mfctl(16) - rangetime;

        printk(KERN_DEBUG "Whole cache flush %lu cycles, flushing %lu bytes %lu cycles\n",
                alltime, size, rangetime);

        threshold = L1_CACHE_ALIGN((unsigned long)((uint64_t)size * alltime / rangetime));
        pr_info("Calculated flush threshold is %lu KiB\n",
                threshold/1024);

        /*
         * The threshold computed above isn't very reliable. The following
         * heuristic works reasonably well on c8000/rp3440.
         */
        threshold2 = cache_info.dc_size * num_online_cpus();
        parisc_cache_flush_threshold = threshold2;
        printk(KERN_INFO "Cache flush threshold set to %lu KiB\n",
                parisc_cache_flush_threshold/1024);

        /* calculate TLB flush threshold */

        /* On SMP machines, skip the TLB measure of kernel text which
         * has been mapped as huge pages. */
        if (num_online_cpus() > 1 && !parisc_requires_coherency()) {
                threshold = max(cache_info.it_size, cache_info.dt_size);
                threshold *= PAGE_SIZE;
                threshold /= num_online_cpus();
                goto set_tlb_threshold;
        }

        size = (unsigned long)_end - (unsigned long)_text;
        rangetime = mfctl(16);
        flush_tlb_kernel_range((unsigned long)_text, (unsigned long)_end);
        rangetime = mfctl(16) - rangetime;

        alltime = mfctl(16);
        flush_tlb_all();
        alltime = mfctl(16) - alltime;

        printk(KERN_INFO "Whole TLB flush %lu cycles, Range flush %lu bytes %lu cycles\n",
                alltime, size, rangetime);

        threshold = PAGE_ALIGN((num_online_cpus() * size * alltime) / rangetime);
        printk(KERN_INFO "Calculated TLB flush threshold %lu KiB\n",
                threshold/1024);

set_tlb_threshold:
        parisc_tlb_flush_threshold = max(threshold, FLUSH_TLB_THRESHOLD);
        printk(KERN_INFO "TLB flush threshold set to %lu KiB\n",
                parisc_tlb_flush_threshold/1024);
}

extern void purge_kernel_dcache_page_asm(unsigned long);
extern void clear_user_page_asm(void *, unsigned long);
extern void copy_user_page_asm(void *, void *, unsigned long);

static void flush_cache_page_if_present(struct vm_area_struct *vma,
        unsigned long vmaddr)
{
#if CONFIG_FLUSH_PAGE_ACCESSED
        bool needs_flush = false;
        pte_t *ptep, pte;

        ptep = get_ptep(vma->vm_mm, vmaddr);
        if (ptep) {
                pte = ptep_get(ptep);
                needs_flush = pte_needs_flush(pte);
                pte_unmap(ptep);
        }
        if (needs_flush)
                __flush_cache_page(vma, vmaddr, PFN_PHYS(pte_pfn(pte)));
#else
        struct mm_struct *mm = vma->vm_mm;
        unsigned long physaddr = get_upa(mm, vmaddr);

        if (physaddr)
                __flush_cache_page(vma, vmaddr, PAGE_ALIGN_DOWN(physaddr));
#endif
}

void copy_user_highpage(struct page *to, struct page *from,
        unsigned long vaddr, struct vm_area_struct *vma)
{
        void *kto, *kfrom;

        kfrom = kmap_local_page(from);
        kto = kmap_local_page(to);
        __flush_cache_page(vma, vaddr, PFN_PHYS(page_to_pfn(from)));
        copy_page_asm(kto, kfrom);
        kunmap_local(kto);
        kunmap_local(kfrom);
}

void copy_to_user_page(struct vm_area_struct *vma, struct page *page,
                unsigned long user_vaddr, void *dst, void *src, int len)
{
        __flush_cache_page(vma, user_vaddr, PFN_PHYS(page_to_pfn(page)));
        memcpy(dst, src, len);
        flush_kernel_dcache_page_addr(PTR_PAGE_ALIGN_DOWN(dst));
}

void copy_from_user_page(struct vm_area_struct *vma, struct page *page,
                unsigned long user_vaddr, void *dst, void *src, int len)
{
        __flush_cache_page(vma, user_vaddr, PFN_PHYS(page_to_pfn(page)));
        memcpy(dst, src, len);
        flush_kernel_dcache_page_addr(PTR_PAGE_ALIGN_DOWN(src));
}

/* __flush_tlb_range()
 *
 * returns 1 if all TLBs were flushed.
 */
int __flush_tlb_range(unsigned long sid, unsigned long start,
                      unsigned long end)
{
        unsigned long flags;

        if ((!IS_ENABLED(CONFIG_SMP) || !arch_irqs_disabled()) &&
            end - start >= parisc_tlb_flush_threshold) {
                flush_tlb_all();
                return 1;
        }

        /* Purge TLB entries for small ranges using the pdtlb and
           pitlb instructions.  These instructions execute locally
           but cause a purge request to be broadcast to other TLBs.  */
        while (start < end) {
                purge_tlb_start(flags);
                mtsp(sid, SR_TEMP1);
                pdtlb(SR_TEMP1, start);
                pitlb(SR_TEMP1, start);
                purge_tlb_end(flags);
                start += PAGE_SIZE;
        }
        return 0;
}

static void flush_cache_pages(struct vm_area_struct *vma, unsigned long start, unsigned long end)
{
        unsigned long addr;

        for (addr = start; addr < end; addr += PAGE_SIZE)
                flush_cache_page_if_present(vma, addr);
}

static inline unsigned long mm_total_size(struct mm_struct *mm)
{
        struct vm_area_struct *vma;
        unsigned long usize = 0;
        VMA_ITERATOR(vmi, mm, 0);

        for_each_vma(vmi, vma) {
                if (usize >= parisc_cache_flush_threshold)
                        break;
                usize += vma->vm_end - vma->vm_start;
        }
        return usize;
}

void flush_cache_mm(struct mm_struct *mm)
{
        struct vm_area_struct *vma;
        VMA_ITERATOR(vmi, mm, 0);

        /*
         * Flushing the whole cache on each cpu takes forever on
         * rp3440, etc. So, avoid it if the mm isn't too big.
         *
         * Note that we must flush the entire cache on machines
         * with aliasing caches to prevent random segmentation
         * faults.
         */
        if (!parisc_requires_coherency()
            ||  mm_total_size(mm) >= parisc_cache_flush_threshold) {
                if (WARN_ON(IS_ENABLED(CONFIG_SMP) && arch_irqs_disabled()))
                        return;
                flush_tlb_all();
                flush_cache_all();
                return;
        }

        /* Flush mm */
        for_each_vma(vmi, vma)
                flush_cache_pages(vma, vma->vm_start, vma->vm_end);
}

void flush_cache_range(struct vm_area_struct *vma, unsigned long start, unsigned long end)
{
        if (!parisc_requires_coherency()
            || end - start >= parisc_cache_flush_threshold) {
                if (WARN_ON(IS_ENABLED(CONFIG_SMP) && arch_irqs_disabled()))
                        return;
                flush_tlb_range(vma, start, end);
                if (vma->vm_flags & VM_EXEC)
                        flush_cache_all();
                else
                        flush_data_cache();
                return;
        }

        flush_cache_pages(vma, start & PAGE_MASK, end);
}

void flush_cache_page(struct vm_area_struct *vma, unsigned long vmaddr, unsigned long pfn)
{
        __flush_cache_page(vma, vmaddr, PFN_PHYS(pfn));
}

void flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
{
        if (!PageAnon(page))
                return;

        __flush_cache_page(vma, vmaddr, PFN_PHYS(page_to_pfn(page)));
}

int ptep_clear_flush_young(struct vm_area_struct *vma, unsigned long addr,
                           pte_t *ptep)
{
        pte_t pte = ptep_get(ptep);

        if (!pte_young(pte))
                return 0;
        set_pte(ptep, pte_mkold(pte));
#if CONFIG_FLUSH_PAGE_ACCESSED
        __flush_cache_page(vma, addr, PFN_PHYS(pte_pfn(pte)));
#endif
        return 1;
}

/*
 * After a PTE is cleared, we have no way to flush the cache for
 * the physical page. On PA8800 and PA8900 processors, these lines
 * can cause random cache corruption. Thus, we must flush the cache
 * as well as the TLB when clearing a PTE that's valid.
 */
pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned long addr,
                       pte_t *ptep)
{
        struct mm_struct *mm = (vma)->vm_mm;
        pte_t pte = ptep_get_and_clear(mm, addr, ptep);
        unsigned long pfn = pte_pfn(pte);

        if (pfn_valid(pfn))
                __flush_cache_page(vma, addr, PFN_PHYS(pfn));
        else if (pte_accessible(mm, pte))
                flush_tlb_page(vma, addr);

        return pte;
}

/*
 * The physical address for pages in the ioremap case can be obtained
 * from the vm_struct struct. I wasn't able to successfully handle the
 * vmalloc and vmap cases. We have an array of struct page pointers in
 * the uninitialized vmalloc case but the flush failed using page_to_pfn.
 */
void flush_cache_vmap(unsigned long start, unsigned long end)
{
        unsigned long addr, physaddr;
        struct vm_struct *vm;

        /* Prevent cache move-in */
        flush_tlb_kernel_range(start, end);

        if (end - start >= parisc_cache_flush_threshold) {
                flush_cache_all();
                return;
        }

        if (WARN_ON_ONCE(!is_vmalloc_addr((void *)start))) {
                flush_cache_all();
                return;
        }

        vm = find_vm_area((void *)start);
        if (WARN_ON_ONCE(!vm)) {
                flush_cache_all();
                return;
        }

        /* The physical addresses of IOREMAP regions are contiguous */
        if (vm->flags & VM_IOREMAP) {
                physaddr = vm->phys_addr;
                for (addr = start; addr < end; addr += PAGE_SIZE) {
                        preempt_disable();
                        flush_dcache_page_asm(physaddr, start);
                        flush_icache_page_asm(physaddr, start);
                        preempt_enable();
                        physaddr += PAGE_SIZE;
                }
                return;
        }

        flush_cache_all();
}
EXPORT_SYMBOL(flush_cache_vmap);

/*
 * The vm_struct has been retired and the page table is set up. The
 * last page in the range is a guard page. Its physical address can't
 * be determined using lpa, so there is no way to flush the range
 * using flush_dcache_page_asm.
 */
void flush_cache_vunmap(unsigned long start, unsigned long end)
{
        /* Prevent cache move-in */
        flush_tlb_kernel_range(start, end);
        flush_data_cache();
}
EXPORT_SYMBOL(flush_cache_vunmap);

/*
 * On systems with PA8800/PA8900 processors, there is no way to flush
 * a vmap range other than using the architected loop to flush the
 * entire cache. The page directory is not set up, so we can't use
 * fdc, etc. FDCE/FICE don't work to flush a portion of the cache.
 * L2 is physically indexed but FDCE/FICE instructions in virtual
 * mode output their virtual address on the core bus, not their
 * real address. As a result, the L2 cache index formed from the
 * virtual address will most likely not be the same as the L2 index
 * formed from the real address.
 */
void flush_kernel_vmap_range(void *vaddr, int size)
{
        unsigned long start = (unsigned long)vaddr;
        unsigned long end = start + size;

        flush_tlb_kernel_range(start, end);

        if (!static_branch_likely(&parisc_has_dcache))
                return;

        /* If interrupts are disabled, we can only do local flush */
        if (WARN_ON(IS_ENABLED(CONFIG_SMP) && arch_irqs_disabled())) {
                flush_data_cache_local(NULL);
                return;
        }

        flush_data_cache();
}
EXPORT_SYMBOL(flush_kernel_vmap_range);

void invalidate_kernel_vmap_range(void *vaddr, int size)
{
        unsigned long start = (unsigned long)vaddr;
        unsigned long end = start + size;

        /* Ensure DMA is complete */
        asm_syncdma();

        flush_tlb_kernel_range(start, end);

        if (!static_branch_likely(&parisc_has_dcache))
                return;

        /* If interrupts are disabled, we can only do local flush */
        if (WARN_ON(IS_ENABLED(CONFIG_SMP) && arch_irqs_disabled())) {
                flush_data_cache_local(NULL);
                return;
        }

        flush_data_cache();
}
EXPORT_SYMBOL(invalidate_kernel_vmap_range);


SYSCALL_DEFINE3(cacheflush, unsigned long, addr, unsigned long, bytes,
        unsigned int, cache)
{
        unsigned long start, end;
        ASM_EXCEPTIONTABLE_VAR(error);

        if (bytes == 0)
                return 0;
        if (!access_ok((void __user *) addr, bytes))
                return -EFAULT;

        end = addr + bytes;

        if (cache & DCACHE) {
                start = addr;
                __asm__ __volatile__ (
#ifdef CONFIG_64BIT
                        "1: cmpb,*<<,n  %0,%2,1b\n"
#else
                        "1: cmpb,<<,n   %0,%2,1b\n"
#endif
                        "   fic,m       %3(%4,%0)\n"
                        "2: sync\n"
                        ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 2b, "%1")
                        : "+r" (start), "+r" (error)
                        : "r" (end), "r" (dcache_stride), "i" (SR_USER));
        }

        if (cache & ICACHE && error == 0) {
                start = addr;
                __asm__ __volatile__ (
#ifdef CONFIG_64BIT
                        "1: cmpb,*<<,n  %0,%2,1b\n"
#else
                        "1: cmpb,<<,n   %0,%2,1b\n"
#endif
                        "   fdc,m       %3(%4,%0)\n"
                        "2: sync\n"
                        ASM_EXCEPTIONTABLE_ENTRY_EFAULT(1b, 2b, "%1")
                        : "+r" (start), "+r" (error)
                        : "r" (end), "r" (icache_stride), "i" (SR_USER));
        }

        return error;
}