Greg Kroah-Hartman
598cf27219
Link: https://lore.kernel.org/r/20260217200002.683975158@linuxfoundation.org Tested-by: Florian Fainelli <florian.fainelli@broadcom.com> Tested-by: Takeshi Ogasawara <takeshi.ogasawara@futuring-girl.com> Tested-by: Peter Schneider <pschneider1968@googlemail.com> Tested-by: Jon Hunter <jonathanh@nvidia.com> Tested-by: Salvatore Bonaccorso <carnil@debian.org> Tested-by: Brett A C Sheffield <bacs@librecast.net> Tested-by: Mark Brown <broonie@kernel.org> Tested-by: Luna Jernberg <droidbittin@gmail.com> Tested-by: Ronald Warsow <rwarsow@gmx.de> Tested-by: Justin M. Forbes <jforbes@fedoraproject.org> Tested-by: Ron Economos <re@w6rz.net> Tested-by: Miguel Ojeda <ojeda@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
50 lines
1.5 KiB
C
50 lines
1.5 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* XIP fixup macros, only useful in assembly.
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*/
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#ifndef _ASM_RISCV_XIP_FIXUP_H
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#define _ASM_RISCV_XIP_FIXUP_H
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#include <linux/pgtable.h>
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#ifdef CONFIG_XIP_KERNEL
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.macro XIP_FIXUP_OFFSET reg
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/* Fix-up address in Flash into address in RAM early during boot before
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* MMU is up. Because generated code "thinks" data is in Flash, but it
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* is actually in RAM (actually data is also in Flash, but Flash is
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* read-only, thus we need to use the data residing in RAM).
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*
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* The start of data in Flash is _sdata and the start of data in RAM is
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* CONFIG_PHYS_RAM_BASE. So this fix-up essentially does this:
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* reg += CONFIG_PHYS_RAM_BASE - _start
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*/
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li t0, CONFIG_PHYS_RAM_BASE
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add \reg, \reg, t0
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la t0, _sdata
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sub \reg, \reg, t0
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.endm
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.macro XIP_FIXUP_FLASH_OFFSET reg
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/* In linker script, at the transition from read-only section to
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* writable section, the VMA is increased while LMA remains the same.
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* (See in linker script how _sdata, __data_loc and LOAD_OFFSET is
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* changed)
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*
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* Consequently, early during boot before MMU is up, the generated code
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* reads the "writable" section at wrong addresses, because VMA is used
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* by compiler to generate code, but the data is located in Flash using
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* LMA.
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*/
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la t0, _sdata
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sub \reg, \reg, t0
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la t0, __data_loc
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add \reg, \reg, t0
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.endm
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#else
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.macro XIP_FIXUP_OFFSET reg
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.endm
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.macro XIP_FIXUP_FLASH_OFFSET reg
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.endm
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#endif /* CONFIG_XIP_KERNEL */
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#endif
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