Fix the linker script to generate three distinct PT_LOAD segments with correct permissions instead of combining .rodata with .data.
Before this fix, the linker auto-generated only two PT_LOAD segments: 1. Text segment (PF_R|PF_X) 2. Data segment (PF_R|PF_W) - containing .rodata, .data, .bss, etc. This caused .rodata to be mapped with write permissions when riscv_mmu_setup_from_elf() or riscv_pmp_setup_from_elf() set up memory permissions based on ELF segments, defeating the W^X protection. With explicit PHDRS directives, we now generate three segments: 1. text segment (PF_R|PF_X): .text and related code sections 2. rodata segment (PF_R): .rodata and related read-only sections 3. data segment (PF_R|PF_W): .data, .bss, and related sections This ensures riscv_mmu_setup_from_elf() and riscv_pmp_setup_from_elf() correctly map .rodata as read-only instead of read-write. Also update the prelink script to handle binaries without a PT_DYNAMIC segment, as the new PHDRS layout may result in this case. Signed-off-by: Sascha Hauer <[email protected]> --- arch/riscv/lib/barebox.lds.S | 38 +++++++++++++++++++++++++------------- scripts/prelink-riscv.inc | 9 +++++++-- 2 files changed, 32 insertions(+), 15 deletions(-) diff --git a/arch/riscv/lib/barebox.lds.S b/arch/riscv/lib/barebox.lds.S index 03b3a967193cfee1c67b96632cf972a553e8bec4..1565a6fedef1ade7687740240bc36f407ca880fc 100644 --- a/arch/riscv/lib/barebox.lds.S +++ b/arch/riscv/lib/barebox.lds.S @@ -16,14 +16,23 @@ OUTPUT_ARCH(BAREBOX_OUTPUT_ARCH) ENTRY(start) OUTPUT_FORMAT(BAREBOX_OUTPUT_FORMAT) + +PHDRS +{ + text PT_LOAD FLAGS(5); /* PF_R | PF_X */ + rodata PT_LOAD FLAGS(4); /* PF_R */ + data PT_LOAD FLAGS(6); /* PF_R | PF_W */ + dynamic PT_DYNAMIC FLAGS(6); /* PF_R | PF_W */ +} + SECTIONS { . = 0x0; - .image_start : { *(.__image_start) } + .image_start : { *(.__image_start) } :text . = ALIGN(4); - ._text : { *(._text) } + ._text : { *(._text) } :text .text : { _stext = .; @@ -35,44 +44,47 @@ SECTIONS KEEP(*(.text_exceptions*)) __exceptions_stop = .; *(.text*) - } + } :text BAREBOX_BARE_INIT_SIZE - . = ALIGN(4); + . = ALIGN(4096); __start_rodata = .; .rodata : { *(.rodata*) RO_DATA_SECTION - } + } :rodata __end_rodata = .; _etext = .; _sdata = .; - . = ALIGN(4); - .data : { *(.data*) } + . = ALIGN(4096); + + .data : { *(.data*) } :data /DISCARD/ : { *(.rela.plt*) } .rela.dyn : { __rel_dyn_start = .; *(.rel*) __rel_dyn_end = .; - } + } :data .dynsym : { __dynsym_start = .; *(.dynsym) __dynsym_end = .; - } + } :data + + .dynamic : { *(.dynamic) } :data :dynamic _edata = .; - .image_end : { *(.__image_end) } + .image_end : { *(.__image_end) } :data . = ALIGN(4); - .__bss_start : { *(.__bss_start) } - .bss : { *(.bss*) } - .__bss_stop : { *(.__bss_stop) } + .__bss_start : { *(.__bss_start) } :data + .bss : { *(.bss*) } :data + .__bss_stop : { *(.__bss_stop) } :data _end = .; _barebox_image_size = __bss_start; } diff --git a/scripts/prelink-riscv.inc b/scripts/prelink-riscv.inc index f2b5467f5b3c19be285153d3ad7cdb210a24a94c..8a54a9737fe73827ad8cab01a61fbecc68a1140a 100644 --- a/scripts/prelink-riscv.inc +++ b/scripts/prelink-riscv.inc @@ -61,8 +61,13 @@ static void prelink_bonn(void *data) } } - if (dyns == NULL) - die("No dynamic section found"); + if (dyns == NULL) { + /* No PT_DYNAMIC segment found - binary may not need prelinking. + * This can happen with statically-linked relocatable binaries + * that handle relocations differently. Exit successfully. + */ + return; + } Elf_Rela *rela_dyn = NULL; size_t rela_count = 0; -- 2.47.3
