cache.c

linux 内核源代码

/* $Id: cache.c,v 1.4 2000/01/25 00:11:38 prumpf Exp $
 *
 * 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 <[e-mail]> (07-13-1999)
 * Copyright (C) 1999 SuSE GmbH Nuernberg
 * Copyright (C) 2000 Philipp Rumpf ([e-mail])
 *
 * 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 <asm/pdc.h>
#include <asm/cache.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include <asm/system.h>
#include <asm/page.h>
#include <asm/pgalloc.h>
#include <asm/processor.h>
#include <asm/sections.h>

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


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

struct pdc_cache_info cache_info __read_mostly;
#ifndef CONFIG_PA20
static struct pdc_btlb_info btlb_info __read_mostly;
#endif

#ifdef CONFIG_SMP
void
flush_data_cache(void)
{
	on_each_cpu(flush_data_cache_local, NULL, 1, 1);
}
void 
flush_instruction_cache(void)
{
	on_each_cpu(flush_instruction_cache_local, NULL, 1, 1);
}
#endif

void
flush_cache_all_local(void)
{
	flush_instruction_cache_local(NULL);
	flush_data_cache_local(NULL);
}
EXPORT_SYMBOL(flush_cache_all_local);

void
update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t pte)
{
	struct page *page = pte_page(pte);

	if (pfn_valid(page_to_pfn(page)) && page_mapping(page) &&
	    test_bit(PG_dcache_dirty, &page->flags)) {

		flush_kernel_dcache_page(page);
		clear_bit(PG_dcache_dirty, &page->flags);
	} else if (parisc_requires_coherency())
		flush_kernel_dcache_page(page);
}

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)\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));
	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("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 pad1 %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_pad1);

	printk("I-TLB conf: sh %d page %d cst %d aid %d pad1 %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_pad1);
#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

#ifndef CONFIG_PA20
	if (pdc_btlb_info(&btlb_info) < 0) {
		memset(&btlb_info, 0, sizeof btlb_info);
	}
#endif

	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");
}

/* Simple function to work out if we have an existing address translation
 * for a user space vma. */
static inline int translation_exists(struct vm_area_struct *vma,
				unsigned long addr, unsigned long pfn)
{
	pgd_t *pgd = pgd_offset(vma->vm_mm, addr);
	pmd_t *pmd;
	pte_t pte;

	if(pgd_none(*pgd))
		return 0;

	pmd = pmd_offset(pgd, addr);
	if(pmd_none(*pmd) || pmd_bad(*pmd))
		return 0;

	/* We cannot take the pte lock here: flush_cache_page is usually
	 * called with pte lock already held.  Whereas flush_dcache_page
	 * takes flush_dcache_mmap_lock, which is lower in the hierarchy:
	 * the vma itself is secure, but the pte might come or go racily.
	 */
	pte = *pte_offset_map(pmd, addr);
	/* But pte_unmap() does nothing on this architecture */

	/* Filter out coincidental file entries and swap entries */
	if (!(pte_val(pte) & (_PAGE_FLUSH|_PAGE_PRESENT)))
		return 0;

	return pte_pfn(pte) == pfn;
}

/* Private function to flush a page from the cache of a non-current
 * process.  cr25 contains the Page Directory of the current user
 * process; we're going to hijack both it and the user space %sr3 to
 * temporarily make the non-current process current.  We have to do
 * this because cache flushing may cause a non-access tlb miss which
 * the handlers have to fill in from the pgd of the non-current
 * process. */
static inline void
flush_user_cache_page_non_current(struct vm_area_struct *vma,
				  unsigned long vmaddr)
{
	/* save the current process space and pgd */
	unsigned long space = mfsp(3), pgd = mfctl(25);

	/* we don't mind taking interrups since they may not
	 * do anything with user space, but we can't
	 * be preempted here */
	preempt_disable();

	/* make us current */
	mtctl(__pa(vma->vm_mm->pgd), 25);
	mtsp(vma->vm_mm->context, 3);

	flush_user_dcache_page(vmaddr);
	if(vma->vm_flags & VM_EXEC)
		flush_user_icache_page(vmaddr);

	/* put the old current process back */
	mtsp(space, 3);
	mtctl(pgd, 25);
	preempt_enable();
}


static inline void
__flush_cache_page(struct vm_area_struct *vma, unsigned long vmaddr)
{
	if (likely(vma->vm_mm->context == mfsp(3))) {
		flush_user_dcache_page(vmaddr);
		if (vma->vm_flags & VM_EXEC)
			flush_user_icache_page(vmaddr);
	} else {
		flush_user_cache_page_non_current(vma, vmaddr);
	}
}

void flush_dcache_page(struct page *page)
{
	struct address_space *mapping = page_mapping(page);
	struct vm_area_struct *mpnt;
	struct prio_tree_iter iter;
	unsigned long offset;
	unsigned long addr;
	pgoff_t pgoff;
	unsigned long pfn = page_to_pfn(page);


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

	flush_kernel_dcache_page(page);

	if (!mapping)
		return;

	pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);

	/* 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 */

	flush_dcache_mmap_lock(mapping);
	vma_prio_tree_foreach(mpnt, &iter, &mapping->i_mmap, pgoff, pgoff) {
		offset = (pgoff - mpnt->vm_pgoff) << PAGE_SHIFT;
		addr = mpnt->vm_start + offset;

		/* Flush instructions produce non access tlb misses.
		 * On PA, we nullify these instructions rather than
		 * taking a page fault if the pte doesn't exist.
		 * This is just for speed.  If the page translation
		 * isn't there, there's no point exciting the
		 * nadtlb handler into a nullification frenzy.
		 *
		 * Make sure we really have this page: the private
		 * mappings may cover this area but have COW'd this
		 * particular page.
		 */
  		if (translation_exists(mpnt, addr, pfn)) {
			__flush_cache_page(mpnt, addr);
			break;
		}
	}
	flush_dcache_mmap_unlock(mapping);
}
EXPORT_SYMBOL(flush_dcache_page);

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

void clear_user_page_asm(void *page, unsigned long vaddr)
{
	/* This function is implemented in assembly in pacache.S */
	extern void __clear_user_page_asm(void *page, unsigned long vaddr);

	purge_tlb_start();
	__clear_user_page_asm(page, vaddr);
	purge_tlb_end();
}

#define FLUSH_THRESHOLD 0x80000 /* 0.5MB */
int parisc_cache_flush_threshold __read_mostly = FLUSH_THRESHOLD;

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

	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);

	/* Racy, but if we see an intermediate value, it's ok too... */
	parisc_cache_flush_threshold = size * alltime / rangetime;

	parisc_cache_flush_threshold = (parisc_cache_flush_threshold + L1_CACHE_BYTES - 1) &~ (L1_CACHE_BYTES - 1); 
	if (!parisc_cache_flush_threshold)
		parisc_cache_flush_threshold = FLUSH_THRESHOLD;

	if (parisc_cache_flush_threshold > cache_info.dc_size)
		parisc_cache_flush_threshold = cache_info.dc_size;

	printk(KERN_INFO "Setting cache flush threshold to %x (%d CPUs online)\n", parisc_cache_flush_threshold, num_online_cpus());
}

extern void purge_kernel_dcache_page(unsigned long);
extern void clear_user_page_asm(void *page, unsigned long vaddr);

void clear_user_page(void *page, unsigned long vaddr, struct page *pg)
{
	purge_kernel_dcache_page((unsigned long)page);
	purge_tlb_start();
	pdtlb_kernel(page);
	purge_tlb_end();
	clear_user_page_asm(page, vaddr);
}
EXPORT_SYMBOL(clear_user_page);

void flush_kernel_dcache_page_addr(void *addr)
{
	flush_kernel_dcache_page_asm(addr);
	purge_tlb_start();
	pdtlb_kernel(addr);
	purge_tlb_end();
}
EXPORT_SYMBOL(flush_kernel_dcache_page_addr);

void copy_user_page(void *vto, void *vfrom, unsigned long vaddr,
		    struct page *pg)
{
	/* no coherency needed (all in kmap/kunmap) */
	copy_user_page_asm(vto, vfrom);
	if (!parisc_requires_coherency())
		flush_kernel_dcache_page_asm(vto);
}
EXPORT_SYMBOL(copy_user_page);

#ifdef CONFIG_PA8X00

void kunmap_parisc(void *addr)
{
	if (parisc_requires_coherency())
		flush_kernel_dcache_page_addr(addr);
}
EXPORT_SYMBOL(kunmap_parisc);
#endif

void __flush_tlb_range(unsigned long sid, unsigned long start,
		       unsigned long end)
{
	unsigned long npages;

	npages = ((end - (start & PAGE_MASK)) + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
	if (npages >= 512)  /* 2MB of space: arbitrary, should be tuned */
		flush_tlb_all();
	else {
		mtsp(sid, 1);
		purge_tlb_start();
		if (split_tlb) {
			while (npages--) {
				pdtlb(start);
				pitlb(start);
				start += PAGE_SIZE;
			}
		} else {
			while (npages--) {
				pdtlb(start);
				start += PAGE_SIZE;
			}
		}
		purge_tlb_end();
	}
}

static void cacheflush_h_tmp_function(void *dummy)
{
	flush_cache_all_local();
}

void flush_cache_all(void)
{
	on_each_cpu(cacheflush_h_tmp_function, NULL, 1, 1);
}

void flush_cache_mm(struct mm_struct *mm)
{
#ifdef CONFIG_SMP
	flush_cache_all();
#else
	flush_cache_all_local();
#endif
}

void
flush_user_dcache_range(unsigned long start, unsigned long end)
{
	if ((end - start) < parisc_cache_flush_threshold)
		flush_user_dcache_range_asm(start,end);
	else
		flush_data_cache();
}

void
flush_user_icache_range(unsigned long start, unsigned long end)
{
	if ((end - start) < parisc_cache_flush_threshold)
		flush_user_icache_range_asm(start,end);
	else
		flush_instruction_cache();
}


void flush_cache_range(struct vm_area_struct *vma,
		unsigned long start, unsigned long end)
{
	int sr3;

	if (!vma->vm_mm->context) {
		BUG();
		return;
	}

	sr3 = mfsp(3);
	if (vma->vm_mm->context == sr3) {
		flush_user_dcache_range(start,end);
		flush_user_icache_range(start,end);
	} else {
		flush_cache_all();
	}
}

void
flush_cache_page(struct vm_area_struct *vma, unsigned long vmaddr, unsigned long pfn)
{
	BUG_ON(!vma->vm_mm->context);

	if (likely(translation_exists(vma, vmaddr, pfn)))
		__flush_cache_page(vma, vmaddr);

}