Lines Matching +full:in +full:- +full:kernel
9 The following documentation is relevant to 2.4.18-rmk6 and beyond.
11 In order to boot ARM Linux, you require a boot loader, which is a small
12 program that runs before the main kernel. The boot loader is expected
13 to initialise various devices, and eventually call the Linux kernel,
14 passing information to the kernel.
22 4. Setup the kernel tagged list.
24 6. Call the kernel image.
28 ---------------------------
36 kernel will use for volatile data storage in the system. It performs
37 this in a machine dependent manner. (It may use internal algorithms
39 the RAM in the machine, or any other method the boot loader designer
44 -----------------------------
52 target. This allows the kernel serial driver to automatically detect
53 which serial port it should use for the kernel console (generally
57 option to the kernel via the tagged lists specifying the port, and
58 serial format options as described in
60 Documentation/admin-guide/kernel-parameters.rst.
64 --------------------------
69 MANDATORY except for DT-only platforms
75 value to the kernel. (see linux/arch/arm/tools/mach-types). This
76 should be passed to the kernel in register r1.
78 For DT-only platforms, the machine type will be determined by device
83 ------------------
91 passing configuration data to the kernel. The physical address of the
92 boot data is passed to the kernel in register r2.
94 4a. Setup the kernel tagged list
95 --------------------------------
97 The boot loader must create and initialise the kernel tagged list.
103 Any number of tags can be placed in the list. It is undefined
105 previous tag, or whether it replaces the information in its
112 +-----------+
113 base -> | ATAG_CORE | |
114 +-----------+ |
116 +-----------+ |
118 +-----------+ v
120 The tagged list should be stored in system RAM.
122 The tagged list must be placed in a region of memory where neither
123 the kernel decompressor nor initrd 'bootp' program will overwrite
124 it. The recommended placement is in the first 16KiB of RAM.
127 -------------------------
132 The kernel will look for the dtb magic value of 0xd00dfeed at the dtb
138 placed in a region of memory where the kernel decompressor will not
140 by the kernel's low-memory mapping.
145 ------------------
152 If an initramfs is in use then, as with the dtb, it must be placed in
153 a region of memory where the kernel decompressor will not overwrite it
154 while also with the region which will be covered by the kernel's
155 low-memory mapping.
161 6. Calling the kernel image
162 ---------------------------
169 There are two options for calling the kernel zImage. If the zImage
170 is stored in flash, and is linked correctly to be run from flash,
171 then it is legal for the boot loader to call the zImage in flash
174 The zImage may also be placed in system RAM and called there. The
175 kernel should be placed in the first 128MiB of RAM. It is recommended
176 that it is loaded above 32MiB in order to avoid the need to relocate
180 When booting a raw (non-zImage) kernel the constraints are tighter.
181 In this case the kernel must be loaded at an offset into system equal
182 to TEXT_OFFSET - PAGE_OFFSET.
184 In any case, the following conditions must be met:
186 - Quiesce all DMA capable devices so that memory does not get
190 - CPU register settings
192 - r0 = 0,
193 - r1 = machine type number discovered in (3) above.
194 - r2 = physical address of tagged list in system RAM, or
195 physical address of device tree block (dtb) in system RAM
197 - CPU mode
202 CPU must be in SVC mode. (A special exception exists for Angel)
205 entered in HYP mode in order to enable the kernel to make full use of
207 unless the virtualisations are already in use by a pre-installed
210 If the kernel is not entered in HYP mode for any reason, it must be
211 entered in SVC mode.
213 - Caches, MMUs
221 If the kernel is entered in HYP mode, the above requirements apply to
222 the HYP mode configuration in addition to the ordinary PL1 (privileged
223 kernel modes) configuration. In addition, all traps into the
226 possible. Except for entering in HYP mode, the system configuration
227 should be such that a kernel which does not include support for the
230 - The boot loader is expected to call the kernel image by jumping
231 directly to the first instruction of the kernel image.
234 made in ARM state, even for a Thumb-2 kernel.
237 Cortex-M class CPUs, the entry must be made in Thumb state.