From: Edward Humes aurxenon@lunos.org
[ Upstream commit b6b17a8b3ecd878d98d5472a9023ede9e669ca72 ]
Previously, R_ALPHA_LITERAL relocations would overflow for large kernel modules.
This was because the Alpha's apply_relocate_add was relying on the kernel's module loader to have sorted the GOT towards the very end of the module as it was mapped into memory in order to correctly assign the global pointer. While this behavior would mostly work fine for small kernel modules, this approach would overflow on kernel modules with large GOT's since the global pointer would be very far away from the GOT, and thus, certain entries would be out of range.
This patch fixes this by instead using the Tru64 behavior of assigning the global pointer to be 32KB away from the start of the GOT. The change made in this patch won't work for multi-GOT kernel modules as it makes the assumption the module only has one GOT located at the beginning of .got, although for the vast majority kernel modules, this should be fine. Of the kernel modules that would previously result in a relocation error, none of them, even modules like nouveau, have even come close to filling up a single GOT, and they've all worked fine under this patch.
Signed-off-by: Edward Humes aurxenon@lunos.org Signed-off-by: Matt Turner mattst88@gmail.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/alpha/kernel/module.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/arch/alpha/kernel/module.c b/arch/alpha/kernel/module.c index ac110ae8f9780..b19a8aae74e1f 100644 --- a/arch/alpha/kernel/module.c +++ b/arch/alpha/kernel/module.c @@ -146,10 +146,8 @@ apply_relocate_add(Elf64_Shdr *sechdrs, const char *strtab, base = (void *)sechdrs[sechdrs[relsec].sh_info].sh_addr; symtab = (Elf64_Sym *)sechdrs[symindex].sh_addr;
- /* The small sections were sorted to the end of the segment. - The following should definitely cover them. */ - gp = (u64)me->core_layout.base + me->core_layout.size - 0x8000; got = sechdrs[me->arch.gotsecindex].sh_addr; + gp = got + 0x8000;
for (i = 0; i < n; i++) { unsigned long r_sym = ELF64_R_SYM (rela[i].r_info);