diff options
Diffstat (limited to 'arch/cris/mm')
| -rw-r--r-- | arch/cris/mm/Makefile | 6 | ||||
| -rw-r--r-- | arch/cris/mm/fault.c | 387 | ||||
| -rw-r--r-- | arch/cris/mm/init.c | 225 | ||||
| -rw-r--r-- | arch/cris/mm/ioremap.c | 146 | ||||
| -rw-r--r-- | arch/cris/mm/tlb.c | 126 |
5 files changed, 890 insertions, 0 deletions
diff --git a/arch/cris/mm/Makefile b/arch/cris/mm/Makefile new file mode 100644 index 0000000..d3ae08c --- /dev/null +++ b/arch/cris/mm/Makefile @@ -0,0 +1,6 @@ +# +# Makefile for the linux cris-specific parts of the memory manager. +# + +obj-y := init.o fault.o tlb.o ioremap.o + diff --git a/arch/cris/mm/fault.c b/arch/cris/mm/fault.c new file mode 100644 index 0000000..03254b9 --- /dev/null +++ b/arch/cris/mm/fault.c @@ -0,0 +1,387 @@ +/* + * linux/arch/cris/mm/fault.c + * + * Copyright (C) 2000, 2001 Axis Communications AB + * + * Authors: Bjorn Wesen + * + * $Log: fault.c,v $ + * Revision 1.11 2004/05/14 07:58:05 starvik + * Merge of changes from 2.4 + * + * Revision 1.10 2003/10/27 14:51:24 starvik + * Removed debugcode + * + * Revision 1.9 2003/10/27 14:50:42 starvik + * Changed do_page_fault signature + * + * Revision 1.8 2003/07/04 13:02:48 tobiasa + * Moved code snippet from arch/cris/mm/fault.c that searches for fixup code + * to seperate function in arch-specific files. + * + * Revision 1.7 2003/01/22 06:48:38 starvik + * Fixed warnings issued by GCC 3.2.1 + * + * Revision 1.6 2003/01/09 14:42:52 starvik + * Merge of Linux 2.5.55 + * + * Revision 1.5 2002/12/11 14:44:48 starvik + * Extracted v10 (ETRAX 100LX) specific stuff to arch/cris/arch-v10/mm + * + * Revision 1.4 2002/11/13 15:10:28 starvik + * pte_offset has been renamed to pte_offset_kernel + * + * Revision 1.3 2002/11/05 06:45:13 starvik + * Merge of Linux 2.5.45 + * + * Revision 1.2 2001/12/18 13:35:22 bjornw + * Applied the 2.4.13->2.4.16 CRIS patch to 2.5.1 (is a copy of 2.4.15). + * + * Revision 1.20 2001/11/22 13:34:06 bjornw + * * Bug workaround (LX TR89): force a rerun of the whole of an interrupted + * unaligned write, because the second half of the write will be corrupted + * otherwise. Affected unaligned writes spanning not-yet mapped pages. + * * Optimization: use the wr_rd bit in R_MMU_CAUSE to know whether a miss + * was due to a read or a write (before we didn't know this until the next + * restart of the interrupted instruction, thus wasting one fault-irq) + * + * Revision 1.19 2001/11/12 19:02:10 pkj + * Fixed compiler warnings. + * + * Revision 1.18 2001/07/18 22:14:32 bjornw + * Enable interrupts in the bulk of do_page_fault + * + * Revision 1.17 2001/07/18 13:07:23 bjornw + * * Detect non-existant PTE's in vmalloc pmd synchronization + * * Remove comment about fast-paths for VMALLOC_START etc, because all that + * was totally bogus anyway it turned out :) + * * Fix detection of vmalloc-area synchronization + * * Add some comments + * + * Revision 1.16 2001/06/13 00:06:08 bjornw + * current_pgd should be volatile + * + * Revision 1.15 2001/06/13 00:02:23 bjornw + * Use a separate variable to store the current pgd to avoid races in schedule + * + * Revision 1.14 2001/05/16 17:41:07 hp + * Last comment tweak further tweaked. + * + * Revision 1.13 2001/05/15 00:58:44 hp + * Expand a bit on the comment why we compare address >= TASK_SIZE rather + * than >= VMALLOC_START. + * + * Revision 1.12 2001/04/04 10:51:14 bjornw + * mmap_sem is grabbed for reading + * + * Revision 1.11 2001/03/23 07:36:07 starvik + * Corrected according to review remarks + * + * Revision 1.10 2001/03/21 16:10:11 bjornw + * CRIS_FRAME_FIXUP not needed anymore, use FRAME_NORMAL + * + * Revision 1.9 2001/03/05 13:22:20 bjornw + * Spell-fix and fix in vmalloc_fault handling + * + * Revision 1.8 2000/11/22 14:45:31 bjornw + * * 2.4.0-test10 removed the set_pgdir instantaneous kernel global mapping + * into all processes. Instead we fill in the missing PTE entries on demand. + * + * Revision 1.7 2000/11/21 16:39:09 bjornw + * fixup switches frametype + * + * Revision 1.6 2000/11/17 16:54:08 bjornw + * More detailed siginfo reporting + * + * + */ + +#include <linux/mm.h> +#include <linux/interrupt.h> +#include <linux/module.h> +#include <asm/uaccess.h> + +extern int find_fixup_code(struct pt_regs *); +extern void die_if_kernel(const char *, struct pt_regs *, long); + +/* debug of low-level TLB reload */ +#undef DEBUG + +#ifdef DEBUG +#define D(x) x +#else +#define D(x) +#endif + +/* debug of higher-level faults */ +#define DPG(x) + +/* current active page directory */ + +volatile pgd_t *current_pgd; + +/* + * This routine handles page faults. It determines the address, + * and the problem, and then passes it off to one of the appropriate + * routines. + * + * Notice that the address we're given is aligned to the page the fault + * occurred in, since we only get the PFN in R_MMU_CAUSE not the complete + * address. + * + * error_code: + * bit 0 == 0 means no page found, 1 means protection fault + * bit 1 == 0 means read, 1 means write + * + * If this routine detects a bad access, it returns 1, otherwise it + * returns 0. + */ + +asmlinkage void +do_page_fault(unsigned long address, struct pt_regs *regs, + int protection, int writeaccess) +{ + struct task_struct *tsk; + struct mm_struct *mm; + struct vm_area_struct * vma; + siginfo_t info; + + D(printk("Page fault for %X at %X, prot %d write %d\n", + address, regs->erp, protection, writeaccess)); + + tsk = current; + + /* + * We fault-in kernel-space virtual memory on-demand. The + * 'reference' page table is init_mm.pgd. + * + * NOTE! We MUST NOT take any locks for this case. We may + * be in an interrupt or a critical region, and should + * only copy the information from the master page table, + * nothing more. + * + * NOTE2: This is done so that, when updating the vmalloc + * mappings we don't have to walk all processes pgdirs and + * add the high mappings all at once. Instead we do it as they + * are used. However vmalloc'ed page entries have the PAGE_GLOBAL + * bit set so sometimes the TLB can use a lingering entry. + * + * This verifies that the fault happens in kernel space + * and that the fault was not a protection error (error_code & 1). + */ + + if (address >= VMALLOC_START && + !protection && + !user_mode(regs)) + goto vmalloc_fault; + + /* we can and should enable interrupts at this point */ + sti(); + + mm = tsk->mm; + info.si_code = SEGV_MAPERR; + + /* + * If we're in an interrupt or have no user + * context, we must not take the fault.. + */ + + if (in_interrupt() || !mm) + goto no_context; + + down_read(&mm->mmap_sem); + vma = find_vma(mm, address); + if (!vma) + goto bad_area; + if (vma->vm_start <= address) + goto good_area; + if (!(vma->vm_flags & VM_GROWSDOWN)) + goto bad_area; + if (user_mode(regs)) { + /* + * accessing the stack below usp is always a bug. + * we get page-aligned addresses so we can only check + * if we're within a page from usp, but that might be + * enough to catch brutal errors at least. + */ + if (address + PAGE_SIZE < rdusp()) + goto bad_area; + } + if (expand_stack(vma, address)) + goto bad_area; + + /* + * Ok, we have a good vm_area for this memory access, so + * we can handle it.. + */ + + good_area: + info.si_code = SEGV_ACCERR; + + /* first do some preliminary protection checks */ + + if (writeaccess) { + if (!(vma->vm_flags & VM_WRITE)) + goto bad_area; + } else { + if (!(vma->vm_flags & (VM_READ | VM_EXEC))) + goto bad_area; + } + + /* + * If for any reason at all we couldn't handle the fault, + * make sure we exit gracefully rather than endlessly redo + * the fault. + */ + + switch (handle_mm_fault(mm, vma, address, writeaccess)) { + case 1: + tsk->min_flt++; + break; + case 2: + tsk->maj_flt++; + break; + case 0: + goto do_sigbus; + default: + goto out_of_memory; + } + + up_read(&mm->mmap_sem); + return; + + /* + * Something tried to access memory that isn't in our memory map.. + * Fix it, but check if it's kernel or user first.. + */ + + bad_area: + up_read(&mm->mmap_sem); + + bad_area_nosemaphore: + DPG(show_registers(regs)); + + /* User mode accesses just cause a SIGSEGV */ + + if (user_mode(regs)) { + info.si_signo = SIGSEGV; + info.si_errno = 0; + /* info.si_code has been set above */ + info.si_addr = (void *)address; + force_sig_info(SIGSEGV, &info, tsk); + return; + } + + no_context: + + /* Are we prepared to handle this kernel fault? + * + * (The kernel has valid exception-points in the source + * when it acesses user-memory. When it fails in one + * of those points, we find it in a table and do a jump + * to some fixup code that loads an appropriate error + * code) + */ + + if (find_fixup_code(regs)) + return; + + /* + * Oops. The kernel tried to access some bad page. We'll have to + * terminate things with extreme prejudice. + */ + + if ((unsigned long) (address) < PAGE_SIZE) + printk(KERN_ALERT "Unable to handle kernel NULL pointer dereference"); + else + printk(KERN_ALERT "Unable to handle kernel access"); + printk(" at virtual address %08lx\n",address); + + die_if_kernel("Oops", regs, (writeaccess << 1) | protection); + + do_exit(SIGKILL); + + /* + * We ran out of memory, or some other thing happened to us that made + * us unable to handle the page fault gracefully. + */ + + out_of_memory: + up_read(&mm->mmap_sem); + printk("VM: killing process %s\n", tsk->comm); + if (user_mode(regs)) + do_exit(SIGKILL); + goto no_context; + + do_sigbus: + up_read(&mm->mmap_sem); + + /* + * Send a sigbus, regardless of whether we were in kernel + * or user mode. + */ + info.si_signo = SIGBUS; + info.si_errno = 0; + info.si_code = BUS_ADRERR; + info.si_addr = (void *)address; + force_sig_info(SIGBUS, &info, tsk); + + /* Kernel mode? Handle exceptions or die */ + if (!user_mode(regs)) + goto no_context; + return; + +vmalloc_fault: + { + /* + * Synchronize this task's top level page-table + * with the 'reference' page table. + * + * Use current_pgd instead of tsk->active_mm->pgd + * since the latter might be unavailable if this + * code is executed in a misfortunately run irq + * (like inside schedule() between switch_mm and + * switch_to...). + */ + + int offset = pgd_index(address); + pgd_t *pgd, *pgd_k; + pmd_t *pmd, *pmd_k; + pte_t *pte_k; + + pgd = (pgd_t *)current_pgd + offset; + pgd_k = init_mm.pgd + offset; + + /* Since we're two-level, we don't need to do both + * set_pgd and set_pmd (they do the same thing). If + * we go three-level at some point, do the right thing + * with pgd_present and set_pgd here. + * + * Also, since the vmalloc area is global, we don't + * need to copy individual PTE's, it is enough to + * copy the pgd pointer into the pte page of the + * root task. If that is there, we'll find our pte if + * it exists. + */ + + pmd = pmd_offset(pgd, address); + pmd_k = pmd_offset(pgd_k, address); + + if (!pmd_present(*pmd_k)) + goto bad_area_nosemaphore; + + set_pmd(pmd, *pmd_k); + + /* Make sure the actual PTE exists as well to + * catch kernel vmalloc-area accesses to non-mapped + * addresses. If we don't do this, this will just + * silently loop forever. + */ + + pte_k = pte_offset_kernel(pmd_k, address); + if (!pte_present(*pte_k)) + goto no_context; + + return; + } +} diff --git a/arch/cris/mm/init.c b/arch/cris/mm/init.c new file mode 100644 index 0000000..31a0018 --- /dev/null +++ b/arch/cris/mm/init.c @@ -0,0 +1,225 @@ +/* + * linux/arch/cris/mm/init.c + * + * Copyright (C) 1995 Linus Torvalds + * Copyright (C) 2000,2001 Axis Communications AB + * + * Authors: Bjorn Wesen (bjornw@axis.com) + * + * $Log: init.c,v $ + * Revision 1.11 2004/05/28 09:28:56 starvik + * Calculation of loops_per_usec moved because initalization order has changed + * in Linux 2.6. + * + * Revision 1.10 2004/05/14 07:58:05 starvik + * Merge of changes from 2.4 + * + * Revision 1.9 2003/07/04 08:27:54 starvik + * Merge of Linux 2.5.74 + * + * Revision 1.8 2003/04/09 05:20:48 starvik + * Merge of Linux 2.5.67 + * + * Revision 1.7 2003/01/22 06:48:38 starvik + * Fixed warnings issued by GCC 3.2.1 + * + * Revision 1.6 2002/12/11 14:44:48 starvik + * Extracted v10 (ETRAX 100LX) specific stuff to arch/cris/arch-v10/mm + * + * Revision 1.5 2002/11/18 07:37:37 starvik + * Added cache bug workaround (from Linux 2.4) + * + * Revision 1.4 2002/11/13 15:40:24 starvik + * Removed the page table cache stuff (as done in other archs) + * + * Revision 1.3 2002/11/05 06:45:13 starvik + * Merge of Linux 2.5.45 + * + * Revision 1.2 2001/12/18 13:35:22 bjornw + * Applied the 2.4.13->2.4.16 CRIS patch to 2.5.1 (is a copy of 2.4.15). + * + * Revision 1.31 2001/11/13 16:22:00 bjornw + * Skip calculating totalram and sharedram in si_meminfo + * + * Revision 1.30 2001/11/12 19:02:10 pkj + * Fixed compiler warnings. + * + * Revision 1.29 2001/07/25 16:09:50 bjornw + * val->sharedram will stay 0 + * + * Revision 1.28 2001/06/28 16:30:17 bjornw + * Oops. This needs to wait until 2.4.6 is merged + * + * Revision 1.27 2001/06/28 14:04:07 bjornw + * Fill in sharedram + * + * Revision 1.26 2001/06/18 06:36:02 hp + * Enable free_initmem of __init-type pages + * + * Revision 1.25 2001/06/13 00:02:23 bjornw + * Use a separate variable to store the current pgd to avoid races in schedule + * + * Revision 1.24 2001/05/15 00:52:20 hp + * Only map segment 0xa as seg if CONFIG_JULIETTE + * + * Revision 1.23 2001/04/04 14:35:40 bjornw + * * Removed get_pte_slow and friends (2.4.3 change) + * * Removed bad_pmd handling (2.4.3 change) + * + * Revision 1.22 2001/04/04 13:38:04 matsfg + * Moved ioremap to a separate function instead + * + * Revision 1.21 2001/03/27 09:28:33 bjornw + * ioremap used too early - lets try it in mem_init instead + * + * Revision 1.20 2001/03/23 07:39:21 starvik + * Corrected according to review remarks + * + * Revision 1.19 2001/03/15 14:25:17 bjornw + * More general shadow registers and ioremaped addresses for external I/O + * + * Revision 1.18 2001/02/23 12:46:44 bjornw + * * 0xc was not CSE1; 0x8 is, same as uncached flash, so we move the uncached + * flash during CRIS_LOW_MAP from 0xe to 0x8 so both the flash and the I/O + * is mapped straight over (for !CRIS_LOW_MAP the uncached flash is still 0xe) + * + * Revision 1.17 2001/02/22 15:05:21 bjornw + * Map 0x9 straight over during LOW_MAP to allow for memory mapped LEDs + * + * Revision 1.16 2001/02/22 15:02:35 bjornw + * Map 0xc straight over during LOW_MAP to allow for memory mapped I/O + * + * Revision 1.15 2001/01/10 21:12:10 bjornw + * loops_per_sec -> loops_per_jiffy + * + * Revision 1.14 2000/11/22 16:23:20 bjornw + * Initialize totalhigh counters to 0 to make /proc/meminfo look nice. + * + * Revision 1.13 2000/11/21 16:37:51 bjornw + * Temporarily disable initmem freeing + * + * Revision 1.12 2000/11/21 13:55:07 bjornw + * Use CONFIG_CRIS_LOW_MAP for the low VM map instead of explicit CPU type + * + * Revision 1.11 2000/10/06 12:38:22 bjornw + * Cast empty_bad_page correctly (should really be of * type from the start.. + * + * Revision 1.10 2000/10/04 16:53:57 bjornw + * Fix memory-map due to LX features + * + * Revision 1.9 2000/09/13 15:47:49 bjornw + * Wrong count in reserved-pages loop + * + * Revision 1.8 2000/09/13 14:35:10 bjornw + * 2.4.0-test8 added a new arg to free_area_init_node + * + * Revision 1.7 2000/08/17 15:35:55 bjornw + * 2.4.0-test6 removed MAP_NR and inserted virt_to_page + * + * + */ + +#include <linux/init.h> +#include <linux/bootmem.h> +#include <asm/tlb.h> + +DEFINE_PER_CPU(struct mmu_gather, mmu_gathers); + +unsigned long empty_zero_page; + +extern char _stext, _edata, _etext; /* From linkerscript */ +extern char __init_begin, __init_end; + +void +show_mem(void) +{ + int i,free = 0,total = 0,cached = 0, reserved = 0, nonshared = 0; + int shared = 0; + + printk("\nMem-info:\n"); + show_free_areas(); + printk("Free swap: %6ldkB\n", nr_swap_pages<<(PAGE_SHIFT-10)); + i = max_mapnr; + while (i-- > 0) { + total++; + if (PageReserved(mem_map+i)) + reserved++; + else if (PageSwapCache(mem_map+i)) + cached++; + else if (!page_count(mem_map+i)) + free++; + else if (page_count(mem_map+i) == 1) + nonshared++; + else + shared += page_count(mem_map+i) - 1; + } + printk("%d pages of RAM\n",total); + printk("%d free pages\n",free); + printk("%d reserved pages\n",reserved); + printk("%d pages nonshared\n",nonshared); + printk("%d pages shared\n",shared); + printk("%d pages swap cached\n",cached); +} + +void __init +mem_init(void) +{ + int codesize, reservedpages, datasize, initsize; + unsigned long tmp; + + if(!mem_map) + BUG(); + + /* max/min_low_pfn was set by setup.c + * now we just copy it to some other necessary places... + * + * high_memory was also set in setup.c + */ + + max_mapnr = num_physpages = max_low_pfn - min_low_pfn; + + /* this will put all memory onto the freelists */ + totalram_pages = free_all_bootmem(); + + reservedpages = 0; + for (tmp = 0; tmp < max_mapnr; tmp++) { + /* + * Only count reserved RAM pages + */ + if (PageReserved(mem_map + tmp)) + reservedpages++; + } + + codesize = (unsigned long) &_etext - (unsigned long) &_stext; + datasize = (unsigned long) &_edata - (unsigned long) &_etext; + initsize = (unsigned long) &__init_end - (unsigned long) &__init_begin; + + printk(KERN_INFO + "Memory: %luk/%luk available (%dk kernel code, %dk reserved, %dk data, " + "%dk init)\n" , + (unsigned long) nr_free_pages() << (PAGE_SHIFT-10), + max_mapnr << (PAGE_SHIFT-10), + codesize >> 10, + reservedpages << (PAGE_SHIFT-10), + datasize >> 10, + initsize >> 10 + ); +} + +/* free the pages occupied by initialization code */ + +void +free_initmem(void) +{ + unsigned long addr; + + addr = (unsigned long)(&__init_begin); + for (; addr < (unsigned long)(&__init_end); addr += PAGE_SIZE) { + ClearPageReserved(virt_to_page(addr)); + set_page_count(virt_to_page(addr), 1); + free_page(addr); + totalram_pages++; + } + printk (KERN_INFO "Freeing unused kernel memory: %luk freed\n", + (unsigned long)((&__init_end - &__init_begin) >> 10)); +} diff --git a/arch/cris/mm/ioremap.c b/arch/cris/mm/ioremap.c new file mode 100644 index 0000000..6b9130b --- /dev/null +++ b/arch/cris/mm/ioremap.c @@ -0,0 +1,146 @@ +/* + * arch/cris/mm/ioremap.c + * + * Re-map IO memory to kernel address space so that we can access it. + * Needed for memory-mapped I/O devices mapped outside our normal DRAM + * window (that is, all memory-mapped I/O devices). + * + * (C) Copyright 1995 1996 Linus Torvalds + * CRIS-port by Axis Communications AB + */ + +#include <linux/vmalloc.h> +#include <asm/io.h> +#include <asm/pgalloc.h> +#include <asm/cacheflush.h> +#include <asm/tlbflush.h> + +extern inline void remap_area_pte(pte_t * pte, unsigned long address, unsigned long size, + unsigned long phys_addr, unsigned long flags) +{ + unsigned long end; + + address &= ~PMD_MASK; + end = address + size; + if (end > PMD_SIZE) + end = PMD_SIZE; + if (address >= end) + BUG(); + do { + if (!pte_none(*pte)) { + printk("remap_area_pte: page already exists\n"); + BUG(); + } + set_pte(pte, mk_pte_phys(phys_addr, __pgprot(_PAGE_PRESENT | __READABLE | + __WRITEABLE | _PAGE_GLOBAL | + _PAGE_KERNEL | flags))); + address += PAGE_SIZE; + phys_addr += PAGE_SIZE; + pte++; + } while (address && (address < end)); +} + +static inline int remap_area_pmd(pmd_t * pmd, unsigned long address, unsigned long size, + unsigned long phys_addr, unsigned long flags) +{ + unsigned long end; + + address &= ~PGDIR_MASK; + end = address + size; + if (end > PGDIR_SIZE) + end = PGDIR_SIZE; + phys_addr -= address; + if (address >= end) + BUG(); + do { + pte_t * pte = pte_alloc_kernel(&init_mm, pmd, address); + if (!pte) + return -ENOMEM; + remap_area_pte(pte, address, end - address, address + phys_addr, flags); + address = (address + PMD_SIZE) & PMD_MASK; + pmd++; + } while (address && (address < end)); + return 0; +} + +static int remap_area_pages(unsigned long address, unsigned long phys_addr, + unsigned long size, unsigned long flags) +{ + int error; + pgd_t * dir; + unsigned long end = address + size; + + phys_addr -= address; + dir = pgd_offset(&init_mm, address); + flush_cache_all(); + if (address >= end) + BUG(); + spin_lock(&init_mm.page_table_lock); + do { + pmd_t *pmd; + pmd = pmd_alloc(&init_mm, dir, address); + error = -ENOMEM; + if (!pmd) + break; + if (remap_area_pmd(pmd, address, end - address, + phys_addr + address, flags)) + break; + error = 0; + address = (address + PGDIR_SIZE) & PGDIR_MASK; + dir++; + } while (address && (address < end)); + spin_unlock(&init_mm.page_table_lock); + flush_tlb_all(); + return error; +} + +/* + * Generic mapping function (not visible outside): + */ + +/* + * Remap an arbitrary physical address space into the kernel virtual + * address space. Needed when the kernel wants to access high addresses + * directly. + * + * NOTE! We need to allow non-page-aligned mappings too: we will obviously + * have to convert them into an offset in a page-aligned mapping, but the + * caller shouldn't need to know that small detail. + */ +void * __ioremap(unsigned long phys_addr, unsigned long size, unsigned long flags) +{ + void * addr; + struct vm_struct * area; + unsigned long offset, last_addr; + + /* Don't allow wraparound or zero size */ + last_addr = phys_addr + size - 1; + if (!size || last_addr < phys_addr) + return NULL; + + /* + * Mappings have to be page-aligned + */ + offset = phys_addr & ~PAGE_MASK; + phys_addr &= PAGE_MASK; + size = PAGE_ALIGN(last_addr+1) - phys_addr; + + /* + * Ok, go for it.. + */ + area = get_vm_area(size, VM_IOREMAP); + if (!area) + return NULL; + addr = area->addr; + if (remap_area_pages((unsigned long) addr, phys_addr, size, flags)) { + vfree(addr); + return NULL; + } + return (void *) (offset + (char *)addr); +} + +void iounmap(void *addr) +{ + if (addr > high_memory) + return vfree((void *) (PAGE_MASK & (unsigned long) addr)); +} diff --git a/arch/cris/mm/tlb.c b/arch/cris/mm/tlb.c new file mode 100644 index 0000000..23eca5a --- /dev/null +++ b/arch/cris/mm/tlb.c @@ -0,0 +1,126 @@ +/* + * linux/arch/cris/mm/tlb.c + * + * Copyright (C) 2000, 2001 Axis Communications AB + * + * Authors: Bjorn Wesen (bjornw@axis.com) + * + */ + +#include <linux/init.h> +#include <asm/tlb.h> + +#define D(x) + +/* The TLB can host up to 64 different mm contexts at the same time. + * The running context is R_MMU_CONTEXT, and each TLB entry contains a + * page_id that has to match to give a hit. In page_id_map, we keep track + * of which mm's we have assigned which page_id's, so that we know when + * to invalidate TLB entries. + * + * The last page_id is never running - it is used as an invalid page_id + * so we can make TLB entries that will never match. + * + * Notice that we need to make the flushes atomic, otherwise an interrupt + * handler that uses vmalloced memory might cause a TLB load in the middle + * of a flush causing. + */ + +struct mm_struct *page_id_map[NUM_PAGEID]; +static int map_replace_ptr = 1; /* which page_id_map entry to replace next */ + +/* + * Initialize the context related info for a new mm_struct + * instance. + */ + +int +init_new_context(struct task_struct *tsk, struct mm_struct *mm) +{ + mm->context = NO_CONTEXT; + return 0; +} + +/* the following functions are similar to those used in the PPC port */ + +static inline void +alloc_context(struct mm_struct *mm) +{ + struct mm_struct *old_mm; + + D(printk("tlb: alloc context %d (%p)\n", map_replace_ptr, mm)); + + /* did we replace an mm ? */ + + old_mm = page_id_map[map_replace_ptr]; + + if(old_mm) { + /* throw out any TLB entries belonging to the mm we replace + * in the map + */ + flush_tlb_mm(old_mm); + + old_mm->context = NO_CONTEXT; + } + + /* insert it into the page_id_map */ + + mm->context = map_replace_ptr; + page_id_map[map_replace_ptr] = mm; + + map_replace_ptr++; + + if(map_replace_ptr == INVALID_PAGEID) + map_replace_ptr = 0; /* wrap around */ +} + +/* + * if needed, get a new MMU context for the mm. otherwise nothing is done. + */ + +void +get_mmu_context(struct mm_struct *mm) +{ + if(mm->context == NO_CONTEXT) + alloc_context(mm); +} + +/* called by __exit_mm to destroy the used MMU context if any before + * destroying the mm itself. this is only called when the last user of the mm + * drops it. + * + * the only thing we really need to do here is mark the used PID slot + * as empty. + */ + +void +destroy_context(struct mm_struct *mm) +{ + if(mm->context != NO_CONTEXT) { + D(printk("destroy_context %d (%p)\n", mm->context, mm)); + flush_tlb_mm(mm); /* TODO this might be redundant ? */ + page_id_map[mm->context] = NULL; + /* mm->context = NO_CONTEXT; redundant.. mm will be freed */ + } +} + +/* called once during VM initialization, from init.c */ + +void __init +tlb_init(void) +{ + int i; + + /* clear the page_id map */ + + for (i = 1; i < sizeof (page_id_map) / sizeof (page_id_map[0]); i++) + page_id_map[i] = NULL; + + /* invalidate the entire TLB */ + + flush_tlb_all(); + + /* the init_mm has context 0 from the boot */ + + page_id_map[0] = &init_mm; +} |
