Commit a9f2fc62 authored by Max Filippov's avatar Max Filippov
Browse files

xtensa: cleanup MMU setup and kernel layout macros 



Make kernel load address explicit, independent of the selected MMU
configuration and configurable from Kconfig. Do not restrict it to the
first 512MB of the physical address space.

Cleanup kernel memory layout macros:

- rename VECBASE_RESET_VADDR to VECBASE_VADDR, XC_VADDR to VECTOR_VADDR;
- drop VIRTUAL_MEMORY_ADDRESS and LOAD_MEMORY_ADDRESS;
- introduce PHYS_OFFSET and use it in __va and __pa definitions;
- synchronize MMU/noMMU vectors, drop unused NMI vector;
- replace hardcoded vectors offset of 0x3000 with Kconfig symbol.

Signed-off-by: default avatarMax Filippov <jcmvbkbc@gmail.com>
parent d39af902

Documentation/xtensa/mmu.txt

+22 −27
Original line number Diff line number Diff line
@@ -3,15 +3,8 @@ MMUv3 initialization sequence. 
The code in the initialize_mmu macro sets up MMUv3 memory mapping

identically to MMUv2 fixed memory mapping. Depending on

CONFIG_INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX symbol this code is

located in one of the following address ranges:



    0xF0000000..0xFFFFFFFF (will keep same address in MMU v2 layout;

    			 typically ROM)

    0x00000000..0x07FFFFFF (system RAM; this code is actually linked

    			 at 0xD0000000..0xD7FFFFFF [cached]

    			 or 0xD8000000..0xDFFFFFFF [uncached];

    			 in any case, initially runs elsewhere

    			 than linked, so have to be careful)

located in addresses it was linked for (symbol undefined), or not

(symbol defined), so it needs to be position-independent.



The code has the following assumptions:

  This code fragment is run only on an MMU v3.
@@ -28,24 +21,26 @@ TLB setup proceeds along the following steps. 
    PA = physical address (two upper nibbles of it);

    pc = physical range that contains this code;



After step 2, we jump to virtual address in 0x40000000..0x5fffffff

that corresponds to next instruction to execute in this code.

After step 4, we jump to intended (linked) address of this code.

After step 2, we jump to virtual address in the range 0x40000000..0x5fffffff

or 0x00000000..0x1fffffff, depending on whether the kernel was loaded below

0x40000000 or above. That address corresponds to next instruction to execute

in this code. After step 4, we jump to intended (linked) address of this code.

The scheme below assumes that the kernel is loaded below 0x40000000.



        Step0  Step1  Step2  Step3          Step4  Step5

 ============  =====  ============  =====  ============  =====

   VA      PA     PA    VA      PA     PA    VA      PA     PA

 ------    --     --  ------    --     --  ------    --     --

 E0..FF -> E0  -> E0  E0..FF -> E0         F0..FF -> F0  -> F0

 C0..DF -> C0  -> C0  C0..DF -> C0         E0..EF -> F0  -> F0

 A0..BF -> A0  -> A0  A0..BF -> A0         D8..DF -> 00  -> 00

 80..9F -> 80  -> 80  80..9F -> 80         D0..D7 -> 00  -> 00

 60..7F -> 60  -> 60  60..7F -> 60

 40..5F -> 40         40..5F -> pc  -> pc  40..5F -> pc

 20..3F -> 20  -> 20  20..3F -> 20

 00..1F -> 00  -> 00  00..1F -> 00



The default location of IO peripherals is above 0xf0000000. This may change

        =====  =====  =====  =====          =====  =====

   VA      PA     PA     PA     PA     VA      PA     PA

 ------    --     --     --     --   ------    --     --

 E0..FF -> E0  -> E0  -> E0          F0..FF -> F0  -> F0

 C0..DF -> C0  -> C0  -> C0          E0..EF -> F0  -> F0

 A0..BF -> A0  -> A0  -> A0          D8..DF -> 00  -> 00

 80..9F -> 80  -> 80  -> 80          D0..D7 -> 00  -> 00

 60..7F -> 60  -> 60  -> 60

 40..5F -> 40         -> pc  -> pc   40..5F -> pc

 20..3F -> 20  -> 20  -> 20

 00..1F -> 00  -> 00  -> 00



The default location of IO peripherals is above 0xf0000000. This may be changed

using a "ranges" property in a device tree simple-bus node. See ePAPR 1.1, §6.5

for details on the syntax and semantic of simple-bus nodes. The following

limitations apply:

arch/xtensa/Kconfig

+20 −6
Original line number Diff line number Diff line
@@ -249,6 +249,25 @@ config KSEG_PADDR 


	  If unsure, leave the default value here.



config KERNEL_LOAD_ADDRESS

	hex "Kernel load address"

	default 0x00003000

	help

	  This is the address where the kernel is loaded.

	  It is virtual address for MMUv2 configurations and physical address

	  for all other configurations.



	  If unsure, leave the default value here.



config VECTORS_OFFSET

	hex "Kernel vectors offset"

	default 0x00003000

	help

	  This is the offset of the kernel image from the relocatable vectors

	  base.



	  If unsure, leave the default value here.



choice

	prompt "KSEG layout"

	depends on MMU
@@ -487,12 +506,7 @@ config DEFAULT_MEM_START 
	  used when no physical memory size is passed through DTB or through

	  boot parameter from bootloader.



	  In noMMU configuration the following parameters are derived from it:

	  - kernel load address;

	  - kernel entry point address;

	  - relocatable vectors base address;

	  - uBoot load address;

	  - TASK_SIZE.

	  It's also used for TASK_SIZE calculation in noMMU configuration.



	  If unsure, leave the default value here.

arch/xtensa/boot/boot-elf/boot.lds.S

+1 −1
Original line number Diff line number Diff line
@@ -23,7 +23,7 @@ SECTIONS 
		*(.ResetVector.text)

	}



	.image KERNELOFFSET: AT (LOAD_MEMORY_ADDRESS)

	.image KERNELOFFSET: AT (CONFIG_KERNEL_LOAD_ADDRESS)

	{

		_image_start = .;

		*(image)

arch/xtensa/boot/boot-elf/bootstrap.S

+6 −1
Original line number Diff line number Diff line
@@ -35,7 +35,12 @@ _ResetVector: 


	.align 4

RomInitAddr:

	.word	LOAD_MEMORY_ADDRESS

#if defined(CONFIG_INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX) && \

	XCHAL_HAVE_PTP_MMU && XCHAL_HAVE_SPANNING_WAY

	.word	CONFIG_KERNEL_LOAD_ADDRESS

#else

	.word	KERNELOFFSET

#endif

RomBootParam:

	.word _bootparam

_bootparam:

arch/xtensa/boot/boot-uboot/Makefile

+1 −9
Original line number Diff line number Diff line
@@ -4,15 +4,7 @@ 
# for more details.

#



ifdef CONFIG_MMU

ifdef CONFIG_INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX

UIMAGE_LOADADDR = 0x00003000

else

UIMAGE_LOADADDR = 0xd0003000

endif

else

UIMAGE_LOADADDR = $(shell printf "0x%x" $$(( ${CONFIG_DEFAULT_MEM_START} + 0x3000 )) )

endif

UIMAGE_LOADADDR = $(CONFIG_KERNEL_LOAD_ADDRESS)

UIMAGE_COMPRESSION = gzip



$(obj)/../uImage: vmlinux.bin.gz FORCE

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