16 lines
864 B
Text
16 lines
864 B
Text
This module was originally written to help work around the security
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feature of NetBSD that prevents read/write access to /dev/mem. It also
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provide Pentium II and AMD K6 MTRR control in order to control
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write-combining to the framebuffer memory.
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XFree86 can take advantage of having direct access to video
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memory (especially with VLB and PCI cards) and even requires it for
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the most recent PCI or AGP video boards.
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This driver works like the standard /dev/mem driver. It just allows
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mapping of the VGA framebuffer and BIOS even if kernel security level
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is > 0. The driver only implements the open(), close(), ioctl() and
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mmap() calls. In order not to defeat kernel security, only one open()
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at a time is allowed and only a process with effective user id of 0 can
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perform it. So while you're running XFree86, no other process will be
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allowed to open /dev/xf86.
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