forked from M-Labs/artiq-zynq
137 lines
3.8 KiB
Rust
137 lines
3.8 KiB
Rust
use alloc::string::String;
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use log::{debug, trace};
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use super::{
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Arch,
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elf::*,
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Error,
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image::{DynamicSection, Image},
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};
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pub trait Relocatable {
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fn offset(&self) -> usize;
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fn type_info(&self) -> u8;
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fn sym_info(&self) -> u32;
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fn addend(&self, image: &Image) -> i32;
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}
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impl Relocatable for Elf32_Rel {
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fn offset(&self) -> usize {
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self.r_offset as usize
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}
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fn type_info(&self) -> u8 {
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ELF32_R_TYPE(self.r_info)
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}
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fn sym_info(&self) -> u32 {
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ELF32_R_SYM(self.r_info)
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}
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fn addend(&self, image: &Image) -> i32 {
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*image.get_ref(self.offset()).unwrap()
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}
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}
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impl Relocatable for Elf32_Rela {
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fn offset(&self) -> usize {
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self.r_offset as usize
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}
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fn type_info(&self) -> u8 {
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ELF32_R_TYPE(self.r_info)
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}
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fn sym_info(&self) -> u32 {
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ELF32_R_SYM(self.r_info)
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}
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fn addend(&self, _: &Image) -> i32 {
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self.r_addend
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}
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}
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#[derive(Clone, Copy, Debug)]
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enum RelType {
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None,
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Relative,
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Lookup,
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}
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impl RelType {
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pub fn new(arch: Arch, type_info: u8) -> Option<Self> {
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match type_info {
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R_OR1K_NONE if arch == Arch::OpenRisc =>
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Some(RelType::None),
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R_ARM_NONE if arch == Arch::Arm =>
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Some(RelType::None),
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R_OR1K_RELATIVE if arch == Arch::OpenRisc =>
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Some(RelType::Relative),
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R_ARM_RELATIVE if arch == Arch::Arm =>
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Some(RelType::Relative),
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R_OR1K_32 | R_OR1K_GLOB_DAT | R_OR1K_JMP_SLOT
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if arch == Arch::OpenRisc => Some(RelType::Lookup),
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R_ARM_GLOB_DAT | R_ARM_JUMP_SLOT
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if arch == Arch::Arm => Some(RelType::Lookup),
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_ =>
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None
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}
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}
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}
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fn format_sym_name(sym_name: &[u8]) -> String {
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core::str::from_utf8(sym_name)
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.map(String::from)
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.unwrap_or(String::from("<invalid symbol name>"))
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}
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pub fn relocate<'a, R: Relocatable>(
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arch: Arch, image: &'a Image, dynamic_section: &'a DynamicSection<'a>,
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rel: &'a R, resolve: &dyn Fn(&[u8]) -> Option<Elf32_Word>
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) -> Result<(), Error> {
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// debug!("rel r_offset={:08X} r_info={:08X} r_addend={:08X}", rel.offset(), rel.r_info, rela.r_addend);
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let sym;
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if rel.sym_info() == 0 {
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sym = None;
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} else {
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sym = Some(dynamic_section.symtab.get(rel.sym_info() as usize)
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.ok_or("symbol out of bounds of symbol table")?)
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}
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let rel_type = RelType::new(arch, rel.type_info())
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.ok_or("unsupported relocation type")?;
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let value;
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match rel_type {
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RelType::None =>
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return Ok(()),
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RelType::Relative => {
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let addend = rel.addend(image);
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value = image.ptr().wrapping_offset(addend as isize) as Elf32_Word;
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}
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RelType::Lookup => {
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let sym = sym.ok_or("relocation requires an associated symbol")?;
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let sym_name = dynamic_section.name_starting_at(sym.st_name as usize)?;
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if let Some(addr) = dynamic_section.lookup(sym_name) {
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// First, try to resolve against itself.
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trace!("looked up symbol {} in image", format_sym_name(sym_name));
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value = image.ptr() as u32 + addr;
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} else if let Some(addr) = resolve(sym_name) {
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// Second, call the user-provided function.
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trace!("resolved symbol {:?}", format_sym_name(sym_name));
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value = addr;
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} else {
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// We couldn't find it anywhere.
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return Err(Error::Lookup(format_sym_name(sym_name)))
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}
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}
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}
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debug!("rel_type={:?} write at {:08X} value {:08X}", rel_type, rel.offset(), value);
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image.write(rel.offset(), value)
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}
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