adriod HAL层 内核空间与用户空间内存共享

1、内核部分
unsignedlonggMmapAddr;
unsignedlonglMmapAddr;

staticintxxx_mmap(structfile*filp,structvm_area_struct*vma)
{
vma->vm_pgoff=((unsignedlong)virt_to_phys(gMmapAddr))>>PAGE_SHIFT;

printk("vma->vm_pgoff=%lx\n",vma->vm_pgoff);

if(remap_pfn_range(vma,vma->vm_start,vma->vm_pgoff,sizeof(gMmapAddr),vma->vm_page_prot))
{
printk("remap_pfn_rangeerror\n");
return-EAGAIN;
}
return0;
}

staticint__initshareMmap_init(void)
{

gMmapAddr=PAGE_ALIGN((UINT32)lMmapAddr);//页对齐，重要

return0;

}

EXPORT_SYMBOL_GPL(gMmapAddr);

这后可以引用gMmapAddr

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2、应用层

unsignedlong*comAddr;

//打开和共享内存驱动
fd=open("/dev/map",O_RDWR);
if(fd<0)
{
returnFALSE;
}

comAddr=(unsignedlong*)mmap(NULL,sizeof(unsignedlong),PROT_READ|PROT_WRITE|PROT_EXEC,MAP_SHARED,fd,0);