arch/ia64/aliasing.rst

2 Memory Attribute Aliasing on IA-64
19         WB		Write-back (cacheable)
21 	WC		Write-coalescing
25     used for memory-mapped I/O devices.  The WC attribute is uncacheable
41     supported attributes for each region.  At boot-time, the kernel uses
62     boot-time information is required for kexec.
75     Therefore, kern_memmap contains only full granule-sized regions that
97 ----------------
112 -----------------------------------------
127 ------------------------------
140 ----------------------
143 	identity mapping.  This is obviously safe for things in
150 	registers typically can be accessed only with four-byte or
151 	eight-byte accesses, and the copy_from_user() path doesn't allow
155 ---------
166 	If the granule contains non-WB memory, but we can cover the
176 --------------------------------------------------------------------
185 mmap of 0x0-0x9FFFF /dev/mem by "hwinfo" on HP sx1000 with VGA enabled
186 ----------------------------------------------------------------------
191         0x00000-0x9FFFF WB only
192         0xA0000-0xBFFFF UC only (VGA frame buffer)
193         0xC0000-0xFFFFF WB only
197       so it is safe to use WB mappings.
200       which uses a granule-sized UC mapping.  This granule will cover some
201       WB-only memory, but since UC is non-speculative, the processor will
202       never generate an uncacheable reference to the WB-only areas unless
205 mmap of 0x0-0xFFFFF legacy_mem by "X"
206 -------------------------------------
214       machines with VGA enabled), we must fail the mmap because there's no
215       safe attribute to use.
218       that doesn't report the VGA frame buffer at all), we should fail the
221 mmap of 0xA0000-0xBFFFF legacy_mem by "X" on HP sx1000 with VGA disabled
222 ------------------------------------------------------------------------
226         0x00000-0xFFFFF WB only (no VGA MMIO hole)
229       fail for the same reason as above.
232 ----------------------------