Jessica Yu <j...@kernel.org> writes: > +++ Nicholas Piggin [15/06/21 12:05 +1000]: >>Excerpts from Jessica Yu's message of June 14, 2021 10:06 pm: >>> +++ Nicholas Piggin [11/06/21 19:39 +1000]: >>>>The elf_check_arch() function is used to test usermode binaries, but >>>>kernel modules may have more specific requirements. powerpc would like >>>>to test for ABI version compatibility. >>>> >>>>Add an arch-overridable function elf_check_module_arch() that defaults >>>>to elf_check_arch() and use it in elf_validity_check(). >>>> >>>>Signed-off-by: Michael Ellerman <m...@ellerman.id.au> >>>>[np: split patch, added changelog] >>>>Signed-off-by: Nicholas Piggin <npig...@gmail.com> >>>>--- >>>> include/linux/moduleloader.h | 5 +++++ >>>> kernel/module.c | 2 +- >>>> 2 files changed, 6 insertions(+), 1 deletion(-) >>>> >>>>diff --git a/include/linux/moduleloader.h b/include/linux/moduleloader.h >>>>index 9e09d11ffe5b..fdc042a84562 100644 >>>>--- a/include/linux/moduleloader.h >>>>+++ b/include/linux/moduleloader.h >>>>@@ -13,6 +13,11 @@ >>>> * must be implemented by each architecture. >>>> */ >>>> >>>>+// Allow arch to optionally do additional checking of module ELF header >>>>+#ifndef elf_check_module_arch >>>>+#define elf_check_module_arch elf_check_arch >>>>+#endif >>> >>> Hi Nicholas, >>> >>> Why not make elf_check_module_arch() consistent with the other >>> arch-specific functions? Please see module_frob_arch_sections(), >>> module_{init,exit}_section(), etc in moduleloader.h. That is, they are >>> all __weak functions that are overridable by arches. We can maybe make >>> elf_check_module_arch() a weak symbol, available for arches to >>> override if they want to perform additional elf checks. Then we don't >>> have to have this one-off #define.
>>Like this? I like it. Good idea. > > Yeah! Also, maybe we can alternatively make elf_check_module_arch() a > separate check entirely so that the powerpc implementation doesn't > have to include that extra elf_check_arch() call. Something like this maybe? My thinking for making elf_check_module_arch() the only hook was that conceivably you might not want/need to call elf_check_arch() from elf_check_module_arch(). So having a single module specific hook allows arch code to decide how to implement the check, which may or may not involve calling elf_check_arch(), but that becomes an arch implementation detail. It's also one arch hook instead of two (although elf_check_arch() already exists). But I don't feel that strongly either way, whatever you prefer. cheers