rtld-elf: Use a proper struct type for tlsdesc entries

This clarifies the code and makes it less error-prone. It also makes it
easier to extend downstream in CheriBSD (where pointer and integer
members no longer have the same representation and an additional member
is present).

Reviewed by:	jhb, kib
Differential Revision:	https://reviews.freebsd.org/D45143
This commit is contained in:
Jessica Clarke 2024-06-05 17:41:54 +01:00
parent 637ee13919
commit 9820007780

View file

@ -183,7 +183,7 @@ struct tls_data {
Elf_Addr tls_offs;
};
static Elf_Addr
static struct tls_data *
reloc_tlsdesc_alloc(int tlsindex, Elf_Addr tlsoffs)
{
struct tls_data *tlsdesc;
@ -193,18 +193,26 @@ reloc_tlsdesc_alloc(int tlsindex, Elf_Addr tlsoffs)
tlsdesc->tls_index = tlsindex;
tlsdesc->tls_offs = tlsoffs;
return ((Elf_Addr)tlsdesc);
return (tlsdesc);
}
struct tlsdesc_entry {
void *(*func)(void *);
union {
Elf_Ssize addend;
Elf_Size offset;
struct tls_data *data;
};
};
static void
reloc_tlsdesc(const Obj_Entry *obj, const Elf_Rela *rela, Elf_Addr *where,
int flags, RtldLockState *lockstate)
reloc_tlsdesc(const Obj_Entry *obj, const Elf_Rela *rela,
struct tlsdesc_entry *where, int flags, RtldLockState *lockstate)
{
const Elf_Sym *def;
const Obj_Entry *defobj;
Elf_Addr offs;
offs = 0;
if (ELF_R_SYM(rela->r_info) != 0) {
def = find_symdef(ELF_R_SYM(rela->r_info), obj, &defobj, flags,
@ -215,8 +223,8 @@ reloc_tlsdesc(const Obj_Entry *obj, const Elf_Rela *rela, Elf_Addr *where,
obj = defobj;
if (def->st_shndx == SHN_UNDEF) {
/* Weak undefined thread variable */
where[0] = (Elf_Addr)_rtld_tlsdesc_undef;
where[1] = rela->r_addend;
where->func = _rtld_tlsdesc_undef;
where->addend = rela->r_addend;
return;
}
}
@ -224,12 +232,12 @@ reloc_tlsdesc(const Obj_Entry *obj, const Elf_Rela *rela, Elf_Addr *where,
if (obj->tlsoffset != 0) {
/* Variable is in initialy allocated TLS segment */
where[0] = (Elf_Addr)_rtld_tlsdesc_static;
where[1] = obj->tlsoffset + offs;
where->func = _rtld_tlsdesc_static;
where->offset = obj->tlsoffset + offs;
} else {
/* TLS offest is unknown at load time, use dynamic resolving */
where[0] = (Elf_Addr)_rtld_tlsdesc_dynamic;
where[1] = reloc_tlsdesc_alloc(obj->tlsindex, offs);
where->func = _rtld_tlsdesc_dynamic;
where->data = reloc_tlsdesc_alloc(obj->tlsindex, offs);
}
}
@ -289,8 +297,8 @@ reloc_plt(Obj_Entry *obj, int flags, RtldLockState *lockstate)
}
break;
case R_AARCH64_TLSDESC:
reloc_tlsdesc(obj, rela, where, SYMLOOK_IN_PLT | flags,
lockstate);
reloc_tlsdesc(obj, rela, (struct tlsdesc_entry *)where,
SYMLOOK_IN_PLT | flags, lockstate);
break;
case R_AARCH64_IRELATIVE:
obj->irelative = true;
@ -549,7 +557,8 @@ reloc_non_plt(Obj_Entry *obj, Obj_Entry *obj_rtld, int flags,
}
break;
case R_AARCH64_TLSDESC:
reloc_tlsdesc(obj, rela, where, flags, lockstate);
reloc_tlsdesc(obj, rela, (struct tlsdesc_entry *)where,
flags, lockstate);
break;
case R_AARCH64_TLS_TPREL64:
/*