ldd3关于remap_pfn_range的一点疑惑

[hhb]

The following does the trick for a driver mapping a region of
simple_region_size bytes, beginning at physical address simple_region_start (which
should be page-aligned):(注释为我的理解)

//off为设备上需要映射内存的偏移量(大小,单位字节)，相对于simple_region_start而言
unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
//设备映射内存的起始地址
unsigned long physical = simple_region_start + off;
//用户用于映射设备物理内存的虚拟内存大小
unsigned long vsize = vma->vm_end - vma->vm_start;
//可用于映射的物理内存的大小
unsigned long psize = simple_region_size - off;
if (vsize > psize)
return -EINVAL; /* spans too high */
remap_pfn_range(vma, vma_>vm_start, physical, vsize, vma->vm_page_prot);
我的问题是，remap_pfn_range的参数physical，是不是应该传入physical>>PAGE_SHIFT,不应该是physical
希望大侠指教

[nevil]

看起来的确是错了,应该传页帧号而不是物理地址,我觉得应该是physical>>PAGE_SHIFT

[hhb]

谢谢版主拔刀相助

[hhb]

上网查了一下该书的勘误，确实有错： unsigned long physical = simple_region_start + off; -> unsigned long pfn = page_to_pfn(simple_region_start + off); remap_pfn_range(vma, vma_>vm_start, physical, vsize, vma->vm_page_prot); -> remap_pfn_range(vma, vma->vm_start, pfn, vsize, vma->vm_page_prot);

[nevil]

嗯,书不可尽信,有问题才是好的

引用 3 楼 hhb 的回复:

上网查了一下该书的勘误，确实有错： unsigned long physical = simple_region_start + off; -> unsigned long pfn = page_to_pfn(simple_region_start + off); remap_pfn_range(vma, vma_>vm_start, physic……