libdyld: fixed symbol relocation #134

pca006132 · 2021-09-25T11:40:05+08:00

pca006132 commented

2021-09-25 11:40:05 +08:00

Note that in libdyld/src/lib.rs #118-119, image pointer is already added to the symbol offset, so we do not need to add the pointer again. It is interesting that we never triggered this bug previously...

2ed2ffe417/src/libdyld/src/lib.rs (L118-L119)

    pub fn lookup(&self, name: &[u8]) -> Option<Elf32_Word> {
        let hash = elf_hash(name);
        let mut index = self.hash_bucket()[hash as usize % self.hash_bucket().len()] as usize;
        loop {
            if index == STN_UNDEF { return None }
            let sym = &self.symtab()[index];
            let sym_name_off = sym.st_name as usize;
            match self.strtab().get(sym_name_off..sym_name_off + name.len()) {
                Some(sym_name) if sym_name == name => {
                    if ELF32_ST_BIND(sym.st_info) & STB_GLOBAL == 0 {
                        return None
                    }
                    match sym.st_shndx {
                        SHN_UNDEF => return None,
                        SHN_ABS => return Some(self.image.ptr() as u32 + sym.st_value),
                        _ => return Some(self.image.ptr() as u32 + sym.st_value)
                    }
                }
                _ => (),
            }
            index = self.hash_chain()[index] as usize;
        }
    }

Note that in libdyld/src/lib.rs #118-119, image pointer is already added to the symbol offset, so we do not need to add the pointer again. It is interesting that we never triggered this bug previously... https://git.m-labs.hk/M-Labs/artiq-zynq/src/commit/2ed2ffe4178573afba9aece4855f74772feb0414/src/libdyld/src/lib.rs#L118-L119 ```rust pub fn lookup(&self, name: &[u8]) -> Option<Elf32_Word> { let hash = elf_hash(name); let mut index = self.hash_bucket()[hash as usize % self.hash_bucket().len()] as usize; loop { if index == STN_UNDEF { return None } let sym = &self.symtab()[index]; let sym_name_off = sym.st_name as usize; match self.strtab().get(sym_name_off..sym_name_off + name.len()) { Some(sym_name) if sym_name == name => { if ELF32_ST_BIND(sym.st_info) & STB_GLOBAL == 0 { return None } match sym.st_shndx { SHN_UNDEF => return None, SHN_ABS => return Some(self.image.ptr() as u32 + sym.st_value), _ => return Some(self.image.ptr() as u32 + sym.st_value) } } _ => (), } index = self.hash_chain()[index] as usize; } } ```

pca006132 added 1 commit 2021-09-25 11:40:07 +08:00

35250b3f56 libdyld: fixed symbol relocation

Note that in libdyld/src/lib.rs #117-118, image pointer is already added
to the symbol offset, so we do not need to add the pointer again

pca006132 referenced this pull request from M-Labs/nac3

2021-09-25 11:40:33 +08:00

UndefinedInstruction error on Zynq #28

pca006132 commented

2021-09-25 11:45:19 +08:00

Poster

Tested with python -m unittest discover artiq.test.coredevice -v.

Tested with `python -m unittest discover artiq.test.coredevice -v`.

sb10q merged commit 35250b3f56 into master

2021-09-25 13:49:49 +08:00

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Reference: M-Labs/artiq-zynq#134