From: Nam Cao Date: Fri, 7 Jun 2024 20:22:09 +0000 (+0200) Subject: riscv: drop the use of XIP_OFFSET in XIP_FIXUP_OFFSET X-Git-Tag: v6.12-rc1~76^2~23^2~4 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=e4eac34feda4959fad754004435512b24af73fe6;p=thirdparty%2Fkernel%2Flinux.git riscv: drop the use of XIP_OFFSET in XIP_FIXUP_OFFSET XIP_OFFSET is the hard-coded offset of writable data section within the kernel. By hard-coding this value, the read-only section of the kernel (which is placed before the writable data section) is restricted in size. As a preparation to remove this hard-coded macro XIP_OFFSET entirely, stop using XIP_OFFSET in XIP_FIXUP_OFFSET. Instead, use CONFIG_PHYS_RAM_BASE and _sdata to do the same thing. While at it, also add a description for XIP_FIXUP_OFFSET. Signed-off-by: Nam Cao Reviewed-by: Alexandre Ghiti Link: https://lore.kernel.org/r/dba0409518b14ee83b346e099b1f7f934daf7b74.1717789719.git.namcao@linutronix.de Signed-off-by: Palmer Dabbelt --- diff --git a/arch/riscv/include/asm/xip_fixup.h b/arch/riscv/include/asm/xip_fixup.h index b65bf6306f69c..9ed2cfae09e0e 100644 --- a/arch/riscv/include/asm/xip_fixup.h +++ b/arch/riscv/include/asm/xip_fixup.h @@ -9,8 +9,19 @@ #ifdef CONFIG_XIP_KERNEL .macro XIP_FIXUP_OFFSET reg - REG_L t0, _xip_fixup + /* 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 la t0, __data_loc @@ -19,7 +30,6 @@ add \reg, \reg, t0 .endm -_xip_fixup: .dword CONFIG_PHYS_RAM_BASE - CONFIG_XIP_PHYS_ADDR - XIP_OFFSET _xip_phys_offset: .dword CONFIG_XIP_PHYS_ADDR + XIP_OFFSET #else .macro XIP_FIXUP_OFFSET reg