内存映射函数remap_pfn_range学习——示例分析(2)
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作者
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概述
正文
一、用alloc_pages来实现
#define alloc_pages(gfp_mask, order) \
alloc_pages_node(numa_node_id(), gfp_mask, order) static inline struct page *alloc_pages_node(int nid, gfp_t gfp_mask,
unsigned int order)
{
if (nid == NUMA_NO_NODE)
nid = numa_mem_id(); return __alloc_pages_node(nid, gfp_mask, order);
}
static struct page *start_page = alloc_pages(GFP_KERNEL, get_order(BUF_SIZE));
这里的BUF_SIZE是32*(PAGE_SIZE),也就是128KB,函数get_order计算可以存放下BUF_SIZE的最小阶数。
static int remap_pfn_mmap(struct file *file, struct vm_area_struct *vma)
{
unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
unsigned long pfn_start = page_to_pfn(start_page) + vma->vm_pgoff;
unsigned long virt_start = (unsigned long)page_address(start_page);
unsigned long size = vma->vm_end - vma->vm_start;
int ret = ; printk("phy: 0x%lx, offset: 0x%lx, size: 0x%lx\n", pfn_start << PAGE_SHIFT, offset, size); ret = remap_pfn_range(vma, vma->vm_start, pfn_start, size, vma->vm_page_prot);
if (ret)
printk("%s: remap_pfn_range failed at [0x%lx 0x%lx]\n",
__func__, vma->vm_start, vma->vm_end);
else
printk("%s: map 0x%lx to 0x%lx, size: 0x%lx\n", __func__, virt_start,
vma->vm_start, size); return ret;
}
二、用vmalloc实现
static void *kbuff = vmalloc(BUF_SIZE);
static int remap_pfn_mmap(struct file *file, struct vm_area_struct *vma)
{
unsigned long offset = vma->vm_pgoff << PAGE_SHIFT;
unsigned long virt_start = (unsigned long)kbuff + (unsigned long)(vma->vm_pgoff << PAGE_SHIFT);
unsigned long pfn_start = (unsigned long)vmalloc_to_pfn((void *)virt_start);
unsigned long size = vma->vm_end - vma->vm_start;
int ret = ;
unsigned long vmstart = vma->vm_start;
int i = ; printk("phy: 0x%lx, offset: 0x%lx, size: 0x%lx\n", pfn_start << PAGE_SHIFT, offset, size); while (size > ) {
ret = remap_pfn_range(vma, vmstart, pfn_start, PAGE_SIZE, vma->vm_page_prot);
if (ret) {
printk("%s: remap_pfn_range failed at [0x%lx 0x%lx]\n",
__func__, vmstart, vmstart + PAGE_SIZE);
ret = -ENOMEM;
goto err;
} else
printk("%s: map 0x%lx (0x%lx) to 0x%lx , size: 0x%lx, number: %d\n", __func__, virt_start,
pfn_start << PAGE_SHIFT, vmstart, PAGE_SIZE, ++i); if (size <= PAGE_SIZE)
size = ;
else {
size -= PAGE_SIZE;
vmstart += PAGE_SIZE;
virt_start += PAGE_SIZE;
pfn_start = vmalloc_to_pfn((void *)virt_start);
}
} return ;
err:
return ret;
}
[11712.435630] client: user_5 ()
[11712.435741] code section: [0x8000 0x8828]
[11712.435839] data section: [0x10828 0x10964]
[11712.435936] brk section: s: 0x11000, c: 0x11000
[11712.436042] mmap section: s: 0xb6f1b000
[11712.436131] stack section: s: 0xbefc6e20
[11712.436256] arg section: [0xbefc6f23 0xbefc6f2c]
[11712.436378] env section: [0xbefc6f2c 0xbefc6ff3]
[11712.436603] phy: 0x9fdf8000, offset: 0x0, size: 0x20000
[11712.436767] remap_pfn_mmap: map 0xf1443000 (0x9fdf8000) to 0xb6d69000 , size: 0x1000, number:
[11712.436991] remap_pfn_mmap: map 0xf1444000 (0x9fdf7000) to 0xb6d6a000 , size: 0x1000, number:
[11712.437210] remap_pfn_mmap: map 0xf1445000 (0x9fdf6000) to 0xb6d6b000 , size: 0x1000, number:
[11712.437429] remap_pfn_mmap: map 0xf1446000 (0x9fdf5000) to 0xb6d6c000 , size: 0x1000, number:
[11712.437647] remap_pfn_mmap: map 0xf1447000 (0x9fdf4000) to 0xb6d6d000 , size: 0x1000, number:
[11712.437862] remap_pfn_mmap: map 0xf1448000 (0x9fdf3000) to 0xb6d6e000 , size: 0x1000, number:
[11712.438086] remap_pfn_mmap: map 0xf1449000 (0x9fdf2000) to 0xb6d6f000 , size: 0x1000, number:
[11712.438305] remap_pfn_mmap: map 0xf144a000 (0x9fdf1000) to 0xb6d70000 , size: 0x1000, number:
[11712.438535] remap_pfn_mmap: map 0xf144b000 (0x9fdf0000) to 0xb6d71000 , size: 0x1000, number:
[11712.438752] remap_pfn_mmap: map 0xf144c000 (0x9fdef000) to 0xb6d72000 , size: 0x1000, number:
[11712.438966] remap_pfn_mmap: map 0xf144d000 (0x9fdee000) to 0xb6d73000 , size: 0x1000, number:
[11712.439198] remap_pfn_mmap: map 0xf144e000 (0x9fded000) to 0xb6d74000 , size: 0x1000, number:
[11712.439404] remap_pfn_mmap: map 0xf144f000 (0x9fdec000) to 0xb6d75000 , size: 0x1000, number:
[11712.440003] remap_pfn_mmap: map 0xf1450000 (0x9fdeb000) to 0xb6d76000 , size: 0x1000, number:
[11712.440145] remap_pfn_mmap: map 0xf1451000 (0x9fdea000) to 0xb6d77000 , size: 0x1000, number:
[11712.440319] remap_pfn_mmap: map 0xf1452000 (0x9fde9000) to 0xb6d78000 , size: 0x1000, number:
[11712.440499] remap_pfn_mmap: map 0xf1453000 (0x9fde8000) to 0xb6d79000 , size: 0x1000, number:
[11712.440680] remap_pfn_mmap: map 0xf1454000 (0x9fde7000) to 0xb6d7a000 , size: 0x1000, number:
[11712.440862] remap_pfn_mmap: map 0xf1455000 (0x9fde6000) to 0xb6d7b000 , size: 0x1000, number:
[11712.441065] remap_pfn_mmap: map 0xf1456000 (0x9fde5000) to 0xb6d7c000 , size: 0x1000, number:
[11712.441520] remap_pfn_mmap: map 0xf1457000 (0x9fde4000) to 0xb6d7d000 , size: 0x1000, number:
[11712.441819] remap_pfn_mmap: map 0xf1458000 (0x9fde3000) to 0xb6d7e000 , size: 0x1000, number:
[11712.442001] remap_pfn_mmap: map 0xf1459000 (0x9fde2000) to 0xb6d7f000 , size: 0x1000, number:
[11712.442182] remap_pfn_mmap: map 0xf145a000 (0x9fde1000) to 0xb6d80000 , size: 0x1000, number:
[11712.442370] remap_pfn_mmap: map 0xf145b000 (0x9fde0000) to 0xb6d81000 , size: 0x1000, number:
[11712.442558] remap_pfn_mmap: map 0xf145c000 (0x9fc0c000) to 0xb6d82000 , size: 0x1000, number:
[11712.442749] remap_pfn_mmap: map 0xf145d000 (0x9fc0d000) to 0xb6d83000 , size: 0x1000, number:
[11712.442944] remap_pfn_mmap: map 0xf145e000 (0x9fdc5000) to 0xb6d84000 , size: 0x1000, number:
[11712.443171] remap_pfn_mmap: map 0xf145f000 (0x9fdf9000) to 0xb6d85000 , size: 0x1000, number:
[11712.443355] remap_pfn_mmap: map 0xf1460000 (0x9fdfa000) to 0xb6d86000 , size: 0x1000, number:
[11712.443534] remap_pfn_mmap: map 0xf1461000 (0x9fdfb000) to 0xb6d87000 , size: 0x1000, number:
[11712.443711] remap_pfn_mmap: map 0xf1462000 (0x9fdfc000) to 0xb6d88000 , size: 0x1000, number:
[11712.442182] remap_pfn_mmap: map 0xf145a000 (0x9fde1000) to 0xb6d80000 , size: 0x1000, number:
[11712.442370] remap_pfn_mmap: map 0xf145b000 (0x9fde0000) to 0xb6d81000 , size: 0x1000, number:
[11712.442558] remap_pfn_mmap: map 0xf145c000 (0x9fc0c000) to 0xb6d82000 , size: 0x1000, number:
[11712.442749] remap_pfn_mmap: map 0xf145d000 (0x9fc0d000) to 0xb6d83000 , size: 0x1000, number:
[11712.442944] remap_pfn_mmap: map 0xf145e000 (0x9fdc5000) to 0xb6d84000 , size: 0x1000, number:
[11712.443171] remap_pfn_mmap: map 0xf145f000 (0x9fdf9000) to 0xb6d85000 , size: 0x1000, number:
[11712.443355] remap_pfn_mmap: map 0xf1460000 (0x9fdfa000) to 0xb6d86000 , size: 0x1000, number:
[11712.443534] remap_pfn_mmap: map 0xf1461000 (0x9fdfb000) to 0xb6d87000 , size: 0x1000, number:
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