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/* SPDX-License-Identifier: GPL-2.0-only */
/*
* XIP fixup macros, only useful in assembly.
*/
#ifndef _ASM_RISCV_XIP_FIXUP_H
#define _ASM_RISCV_XIP_FIXUP_H
#include <linux/pgtable.h>
#ifdef CONFIG_XIP_KERNEL
.macro XIP_FIXUP_OFFSET reg
/* Fix-up address in Flash into address in RAM early during boot before
* MMU is up. Because generated code "thinks" data is in Flash, but it
* is actually in RAM (actually data is also in Flash, but Flash is
* read-only, thus we need to use the data residing in RAM).
*
* The start of data in Flash is _sdata and the start of data in RAM is
* CONFIG_PHYS_RAM_BASE. So this fix-up essentially does this:
* reg += CONFIG_PHYS_RAM_BASE - _start
*/
li t0, CONFIG_PHYS_RAM_BASE
add \reg, \reg, t0
la t0, _sdata
sub \reg, \reg, t0
.endm
.macro XIP_FIXUP_FLASH_OFFSET reg
/* In linker script, at the transition from read-only section to
* writable section, the VMA is increased while LMA remains the same.
* (See in linker script how _sdata, __data_loc and LOAD_OFFSET is
* changed)
*
* Consequently, early during boot before MMU is up, the generated code
* reads the "writable" section at wrong addresses, because VMA is used
* by compiler to generate code, but the data is located in Flash using
* LMA.
*/
la t0, _sdata
sub \reg, \reg, t0
la t0, __data_loc
add \reg, \reg, t0
.endm
#else
.macro XIP_FIXUP_OFFSET reg
.endm
.macro XIP_FIXUP_FLASH_OFFSET reg
.endm
#endif /* CONFIG_XIP_KERNEL */
#endif
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