From: Nam Cao Date: Fri, 7 Jun 2024 20:22:10 +0000 (+0200) Subject: riscv: drop the use of XIP_OFFSET in XIP_FIXUP_FLASH_OFFSET X-Git-Tag: v6.12-rc1~76^2~23^2~3 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=23311f57ee132b2584915d38955b6cf125e76022;p=thirdparty%2Fkernel%2Flinux.git riscv: drop the use of XIP_OFFSET in XIP_FIXUP_FLASH_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_FLASH_OFFSET. Instead, use __data_loc and _sdata to do the same thing. While at it, also add a description for XIP_FIXUP_FLASH_OFFSET. Signed-off-by: Nam Cao Reviewed-by: Alexandre Ghiti Link: https://lore.kernel.org/r/7b3319657edd1822f3457e7e7c07aaa326cc2f87.1717789719.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 9ed2cfae09e0e..f3d56299bc22c 100644 --- a/arch/riscv/include/asm/xip_fixup.h +++ b/arch/riscv/include/asm/xip_fixup.h @@ -24,13 +24,21 @@ 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 - REG_L t1, _xip_phys_offset - sub \reg, \reg, t1 add \reg, \reg, t0 .endm - -_xip_phys_offset: .dword CONFIG_XIP_PHYS_ADDR + XIP_OFFSET #else .macro XIP_FIXUP_OFFSET reg .endm