xtensa: add MMU v3 support (e85e335f) · Commits · 戴 / test

arch/xtensa/Kconfig

+29 −0

Original line number	Diff line number	Diff line
		@@ -103,6 +103,35 @@ config MATH_EMULATION
		help
		Can we use information of configuration file?

		config INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX
		bool "Initialize Xtensa MMU inside the Linux kernel code"
		default y
		help
		Earlier version initialized the MMU in the exception vector
		before jumping to _startup in head.S and had an advantage that
		it was possible to place a software breakpoint at 'reset' and
		then enter your normal kernel breakpoints once the MMU was mapped
		to the kernel mappings (0XC0000000).

		This unfortunately doesn't work for U-Boot and likley also wont
		work for using KEXEC to have a hot kernel ready for doing a
		KDUMP.

		So now the MMU is initialized in head.S but it's necessary to
		use hardware breakpoints (gdb 'hbreak' cmd) to break at _startup.
		xt-gdb can't place a Software Breakpoint in the 0XD region prior
		to mapping the MMU and after mapping even if the area of low memory
		was mapped gdb wouldn't remove the breakpoint on hitting it as the
		PC wouldn't match. Since Hardware Breakpoints are recommended for
		Linux configurations it seems reasonable to just assume they exist
		and leave this older mechanism for unfortunate souls that choose
		not to follow Tensilica's recommendation.

		Selecting this will cause U-Boot to set the KERNEL Load and Entry
		address at 0x00003000 instead of the mapped std of 0xD0003000.

		If in doubt, say Y.

		endmenu

		config XTENSA_CALIBRATE_CCOUNT

arch/xtensa/boot/boot-elf/Makefile

+1 −0

Original line number	Diff line number	Diff line
		@@ -12,6 +12,7 @@ endif

		export OBJCOPY_ARGS
		export CPPFLAGS_boot.lds += -P -C
		export KBUILD_AFLAGS += -mtext-section-literals

		boot-y := bootstrap.o

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

+26 −38

Original line number	Diff line number	Diff line
		#include <variant/core.h>
		/*
		* linux/arch/xtensa/boot/boot-elf/boot.lds.S
		*
		* Copyright (C) 2008 - 2013 by Tensilica Inc.
		*
		* Chris Zankel <chris@zankel.net>
		* Marc Gauthier <marc@tensilica.com
		* Pete Delaney <piet@tensilica.com>
		*
		* This program is free software; you can redistribute it and/or modify
		* it under the terms of the GNU General Public License version 2 as
		* published by the Free Software Foundation.
		*/

		#include <asm/vectors.h>
		OUTPUT_ARCH(xtensa)
		ENTRY(_ResetVector)

		SECTIONS
		{
		.start 0xD0000000 : { *(.start) }

		.text 0xD0000000:
		{
		__reloc_start = . ;
		_text_start = . ;
		*(.literal .text.literal .text)
		_text_end = . ;
		}

		.rodata ALIGN(0x04):
		{
		*(.rodata)
		*(.rodata1)
		}

		.data ALIGN(0x04):
		.ResetVector.text XCHAL_RESET_VECTOR_VADDR :
		{
		*(.data)
		*(.data1)
		*(.sdata)
		*(.sdata2)
		*(.got.plt)
		*(.got)
		*(.dynamic)
		*(.ResetVector.text)
		}

		__reloc_end = . ;

		. = ALIGN(0x10);
		__image_load = . ;
		.image 0xd0001000:
		.image KERNELOFFSET: AT (LOAD_MEMORY_ADDRESS)
		{
		_image_start = .;
		*(image)
		@@ -43,7 +31,6 @@ SECTIONS
		_image_end = . ;
		}


		.bss ((LOADADDR(.image) + SIZEOF(.image) + 3) & ~ 3):
		{
		__bss_start = .;
		@@ -53,14 +40,15 @@ SECTIONS
		*(.bss)
		__bss_end = .;
		}
		_end = .;
		_param_start = .;

		.ResetVector.text XCHAL_RESET_VECTOR_VADDR :
		/*
		* This is a remapped copy of the Reset Vector Code.
		* It keeps gdb in sync with the PC after switching
		* to the temporary mapping used while setting up
		* the V2 MMU mappings for Linux.
		*/
		.ResetVector.remapped_text 0x46000000 (INFO):
		{
		*(.ResetVector.text)
		*(.ResetVector.remapped_text)
		}


		PROVIDE (end = .);
		}

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

+86 −15

Original line number	Diff line number	Diff line
		/*
		* arch/xtensa/boot/boot-elf/bootstrap.S
		*
		* Low-level exception handling
		*
		* This file is subject to the terms and conditions of the GNU General Public
		* License. See the file "COPYING" in the main directory of this archive
		* for more details.
		*
		* Copyright (C) 2004 - 2013 by Tensilica Inc.
		*
		* Chris Zankel <chris@zankel.net>
		* Marc Gauthier <marc@tensilica.com>
		* Piet Delaney <piet@tensilica.com>
		*/

		#include <asm/bootparam.h>
		#include <asm/processor.h>
		#include <asm/pgtable.h>
		#include <asm/page.h>
		#include <asm/cacheasm.h>
		#include <asm/initialize_mmu.h>
		#include <linux/linkage.h>


		/* ResetVector
		*/
		.section .ResetVector.text, "ax"
		.global _ResetVector
		.global reset

		_ResetVector:
		_j reset
		_j _SetupMMU

		.begin no-absolute-literals
		.literal_position

		.align 4
		RomInitAddr:
		.word 0xd0001000
		#if defined(CONFIG_INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX) && \
		XCHAL_HAVE_PTP_MMU && XCHAL_HAVE_SPANNING_WAY
		.word 0x00003000
		#else
		.word 0xd0003000
		#endif
		RomBootParam:
		.word _bootparam
		_bootparam:
		.short BP_TAG_FIRST
		.short 4
		.long BP_VERSION
		.short BP_TAG_LAST
		.short 0
		.long 0

		.align 4
		_SetupMMU:
		movi a0, 0
		wsr a0, windowbase
		rsync
		movi a0, 1
		wsr a0, windowstart
		rsync
		movi a0, 0x1F
		wsr a0, ps
		rsync

		Offset = _SetupMMU - _ResetVector

		#ifndef CONFIG_INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX
		initialize_mmu
		#endif

		.end no-absolute-literals

		rsil a0, XCHAL_DEBUGLEVEL-1
		rsync
		reset:
		l32r a0, RomInitAddr
		l32r a2, RomBootParam
		@@ -21,13 +80,25 @@ reset:
		jx a0

		.align 4
		.section .bootstrap.data, "aw"

		.globl _bootparam
		_bootparam:
		.short BP_TAG_FIRST
		.short 4
		.long BP_VERSION
		.short BP_TAG_LAST
		.short 0
		.long 0
		.section .ResetVector.remapped_text, "x"
		.global _RemappedResetVector

		/* Do org before literals */
		.org 0

		_RemappedResetVector:
		.begin no-absolute-literals
		.literal_position

		_j _RemappedSetupMMU

		/* Position Remapped code at the same location as the original code */
		. = _RemappedResetVector + Offset

		_RemappedSetupMMU:
		#ifndef CONFIG_INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX
		initialize_mmu
		#endif

		.end no-absolute-literals

arch/xtensa/boot/boot-uboot/Makefile

+5 −1

Original line number	Diff line number	Diff line
		@@ -4,7 +4,11 @@
		# for more details.
		#

		UIMAGE_LOADADDR = 0xd0001000
		ifdef CONFIG_INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX
		UIMAGE_LOADADDR = 0x00003000
		else
		UIMAGE_LOADADDR = 0xd0003000
		endif
		UIMAGE_COMPRESSION = gzip

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

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