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| author | Nam Cao <namcao@linutronix.de> | 2024-06-07 22:22:10 +0200 |
|---|---|---|
| committer | Palmer Dabbelt <palmer@rivosinc.com> | 2024-09-12 16:22:59 +0200 |
| commit | 23311f57ee132b2584915d38955b6cf125e76022 (patch) | |
| tree | f5b69affef6066d44e5d1e437573fbe72eb173d9 /arch | |
| parent | riscv: drop the use of XIP_OFFSET in XIP_FIXUP_OFFSET (diff) | |
| download | linux-23311f57ee132b2584915d38955b6cf125e76022.tar.xz linux-23311f57ee132b2584915d38955b6cf125e76022.zip | |
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 <namcao@linutronix.de>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/7b3319657edd1822f3457e7e7c07aaa326cc2f87.1717789719.git.namcao@linutronix.de
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/riscv/include/asm/xip_fixup.h | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/arch/riscv/include/asm/xip_fixup.h b/arch/riscv/include/asm/xip_fixup.h index 9ed2cfae09e0..f3d56299bc22 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 |