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Based on kernel version 3.13. Page generated on 2014-01-20 22:00 EST.

1	Taken from list archive at http://lists.arm.linux.org.uk/pipermail/linux-arm-kernel/2001-July/004064.html
2	
3	Initial definitions
4	-------------------
5	
6	The following symbol definitions rely on you knowing the translation that
7	__virt_to_phys() does for your machine.  This macro converts the passed
8	virtual address to a physical address.  Normally, it is simply:
9	
10			phys = virt - PAGE_OFFSET + PHYS_OFFSET
11	
12	
13	Decompressor Symbols
14	--------------------
15	
16	ZTEXTADDR
17		Start address of decompressor.  There's no point in talking about
18		virtual or physical addresses here, since the MMU will be off at
19		the time when you call the decompressor code.  You normally call
20		the kernel at this address to start it booting.  This doesn't have
21		to be located in RAM, it can be in flash or other read-only or
22		read-write addressable medium.
23	
24	ZBSSADDR
25		Start address of zero-initialised work area for the decompressor.
26		This must be pointing at RAM.  The decompressor will zero initialise
27		this for you.  Again, the MMU will be off.
28	
29	ZRELADDR
30		This is the address where the decompressed kernel will be written,
31		and eventually executed.  The following constraint must be valid:
32	
33			__virt_to_phys(TEXTADDR) == ZRELADDR
34	
35		The initial part of the kernel is carefully coded to be position
36		independent.
37	
38	INITRD_PHYS
39		Physical address to place the initial RAM disk.  Only relevant if
40		you are using the bootpImage stuff (which only works on the old
41		struct param_struct).
42	
43	INITRD_VIRT
44		Virtual address of the initial RAM disk.  The following  constraint
45		must be valid:
46	
47			__virt_to_phys(INITRD_VIRT) == INITRD_PHYS
48	
49	PARAMS_PHYS
50		Physical address of the struct param_struct or tag list, giving the
51		kernel various parameters about its execution environment.
52	
53	
54	Kernel Symbols
55	--------------
56	
57	PHYS_OFFSET
58		Physical start address of the first bank of RAM.
59	
60	PAGE_OFFSET
61		Virtual start address of the first bank of RAM.  During the kernel
62		boot phase, virtual address PAGE_OFFSET will be mapped to physical
63		address PHYS_OFFSET, along with any other mappings you supply.
64		This should be the same value as TASK_SIZE.
65	
66	TASK_SIZE
67		The maximum size of a user process in bytes.  Since user space
68		always starts at zero, this is the maximum address that a user
69		process can access+1.  The user space stack grows down from this
70		address.
71	
72		Any virtual address below TASK_SIZE is deemed to be user process
73		area, and therefore managed dynamically on a process by process
74		basis by the kernel.  I'll call this the user segment.
75	
76		Anything above TASK_SIZE is common to all processes.  I'll call
77		this the kernel segment.
78	
79		(In other words, you can't put IO mappings below TASK_SIZE, and
80		hence PAGE_OFFSET).
81	
82	TEXTADDR
83		Virtual start address of kernel, normally PAGE_OFFSET + 0x8000.
84		This is where the kernel image ends up.  With the latest kernels,
85		it must be located at 32768 bytes into a 128MB region.  Previous
86		kernels placed a restriction of 256MB here.
87	
88	DATAADDR
89		Virtual address for the kernel data segment.  Must not be defined
90		when using the decompressor.
91	
92	VMALLOC_START
93	VMALLOC_END
94		Virtual addresses bounding the vmalloc() area.  There must not be
95		any static mappings in this area; vmalloc will overwrite them.
96		The addresses must also be in the kernel segment (see above).
97		Normally, the vmalloc() area starts VMALLOC_OFFSET bytes above the
98		last virtual RAM address (found using variable high_memory).
99	
100	VMALLOC_OFFSET
101		Offset normally incorporated into VMALLOC_START to provide a hole
102		between virtual RAM and the vmalloc area.  We do this to allow
103		out of bounds memory accesses (eg, something writing off the end
104		of the mapped memory map) to be caught.  Normally set to 8MB.
105	
106	Architecture Specific Macros
107	----------------------------
108	
109	BOOT_MEM(pram,pio,vio)
110		`pram' specifies the physical start address of RAM.  Must always
111		be present, and should be the same as PHYS_OFFSET.
112	
113		`pio' is the physical address of an 8MB region containing IO for
114		use with the debugging macros in arch/arm/kernel/debug-armv.S.
115	
116		`vio' is the virtual address of the 8MB debugging region.
117	
118		It is expected that the debugging region will be re-initialised
119		by the architecture specific code later in the code (via the
120		MAPIO function).
121	
122	BOOT_PARAMS
123		Same as, and see PARAMS_PHYS.
124	
125	FIXUP(func)
126		Machine specific fixups, run before memory subsystems have been
127		initialised.
128	
129	MAPIO(func)
130		Machine specific function to map IO areas (including the debug
131		region above).
132	
133	INITIRQ(func)
134		Machine specific function to initialise interrupts.
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