132 строки
3.1 KiB
C
132 строки
3.1 KiB
C
#include <linux/spinlock.h>
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#include <linux/list.h>
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#include <linux/slab.h>
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#include "vmregion.h"
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/*
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* VM region handling support.
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*
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* This should become something generic, handling VM region allocations for
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* vmalloc and similar (ioremap, module space, etc).
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*
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* I envisage vmalloc()'s supporting vm_struct becoming:
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*
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* struct vm_struct {
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* struct vmregion region;
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* unsigned long flags;
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* struct page **pages;
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* unsigned int nr_pages;
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* unsigned long phys_addr;
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* };
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*
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* get_vm_area() would then call vmregion_alloc with an appropriate
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* struct vmregion head (eg):
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*
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* struct vmregion vmalloc_head = {
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* .vm_list = LIST_HEAD_INIT(vmalloc_head.vm_list),
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* .vm_start = VMALLOC_START,
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* .vm_end = VMALLOC_END,
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* };
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*
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* However, vmalloc_head.vm_start is variable (typically, it is dependent on
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* the amount of RAM found at boot time.) I would imagine that get_vm_area()
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* would have to initialise this each time prior to calling vmregion_alloc().
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*/
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struct arm_vmregion *
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arm_vmregion_alloc(struct arm_vmregion_head *head, size_t size, gfp_t gfp)
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{
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unsigned long addr = head->vm_start, end = head->vm_end - size;
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unsigned long flags;
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struct arm_vmregion *c, *new;
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if (head->vm_end - head->vm_start < size) {
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printk(KERN_WARNING "%s: allocation too big (requested %#x)\n",
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__func__, size);
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goto out;
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}
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new = kmalloc(sizeof(struct arm_vmregion), gfp);
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if (!new)
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goto out;
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spin_lock_irqsave(&head->vm_lock, flags);
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list_for_each_entry(c, &head->vm_list, vm_list) {
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if ((addr + size) < addr)
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goto nospc;
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if ((addr + size) <= c->vm_start)
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goto found;
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addr = c->vm_end;
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if (addr > end)
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goto nospc;
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}
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found:
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/*
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* Insert this entry _before_ the one we found.
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*/
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list_add_tail(&new->vm_list, &c->vm_list);
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new->vm_start = addr;
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new->vm_end = addr + size;
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new->vm_active = 1;
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spin_unlock_irqrestore(&head->vm_lock, flags);
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return new;
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nospc:
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spin_unlock_irqrestore(&head->vm_lock, flags);
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kfree(new);
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out:
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return NULL;
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}
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static struct arm_vmregion *__arm_vmregion_find(struct arm_vmregion_head *head, unsigned long addr)
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{
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struct arm_vmregion *c;
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list_for_each_entry(c, &head->vm_list, vm_list) {
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if (c->vm_active && c->vm_start == addr)
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goto out;
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}
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c = NULL;
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out:
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return c;
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}
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struct arm_vmregion *arm_vmregion_find(struct arm_vmregion_head *head, unsigned long addr)
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{
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struct arm_vmregion *c;
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unsigned long flags;
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spin_lock_irqsave(&head->vm_lock, flags);
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c = __arm_vmregion_find(head, addr);
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spin_unlock_irqrestore(&head->vm_lock, flags);
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return c;
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}
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struct arm_vmregion *arm_vmregion_find_remove(struct arm_vmregion_head *head, unsigned long addr)
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{
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struct arm_vmregion *c;
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unsigned long flags;
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spin_lock_irqsave(&head->vm_lock, flags);
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c = __arm_vmregion_find(head, addr);
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if (c)
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c->vm_active = 0;
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spin_unlock_irqrestore(&head->vm_lock, flags);
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return c;
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}
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void arm_vmregion_free(struct arm_vmregion_head *head, struct arm_vmregion *c)
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{
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unsigned long flags;
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spin_lock_irqsave(&head->vm_lock, flags);
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list_del(&c->vm_list);
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spin_unlock_irqrestore(&head->vm_lock, flags);
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kfree(c);
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}
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