From: Helge Deller Date: Wed, 22 Nov 2023 22:18:12 +0000 (+0100) Subject: modules: Ensure 64-bit alignment on __ksymtab_* sections X-Git-Tag: v6.13-rc1~59^2~17 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=335de24e5e774aa94ff9551b3194fe15f52ea1d9;p=thirdparty%2Flinux.git modules: Ensure 64-bit alignment on __ksymtab_* sections On 64-bit architectures without CONFIG_HAVE_ARCH_PREL32_RELOCATIONS (e.g. ppc64, ppc64le, parisc, s390x,...) the __KSYM_REF() macro stores 64-bit pointers into the __ksymtab* sections. Make sure that those sections will be correctly aligned at module link time, otherwise unaligned memory accesses may happen at runtime. As per unaligned-memory-access [0] "unaligned memory accesses [...] will not work correctly on certain platforms and will cause performance problems on others", so fix this. The __kcrctab* sections store 32-bit entities, so use ALIGN(4) for those. Signed-off-by: Helge Deller [mcgrof: added unaligned-memory-access justification] Link: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/core-api/unaligned-memory-access.rst # [0] Signed-off-by: Luis Chamberlain --- diff --git a/scripts/module.lds.S b/scripts/module.lds.S index 3f43edef813cb..23f9912179cee 100644 --- a/scripts/module.lds.S +++ b/scripts/module.lds.S @@ -18,10 +18,10 @@ SECTIONS { *(.export_symbol) } - __ksymtab 0 : { *(SORT(___ksymtab+*)) } - __ksymtab_gpl 0 : { *(SORT(___ksymtab_gpl+*)) } - __kcrctab 0 : { *(SORT(___kcrctab+*)) } - __kcrctab_gpl 0 : { *(SORT(___kcrctab_gpl+*)) } + __ksymtab 0 : ALIGN(8) { *(SORT(___ksymtab+*)) } + __ksymtab_gpl 0 : ALIGN(8) { *(SORT(___ksymtab_gpl+*)) } + __kcrctab 0 : ALIGN(4) { *(SORT(___kcrctab+*)) } + __kcrctab_gpl 0 : ALIGN(4) { *(SORT(___kcrctab_gpl+*)) } .ctors 0 : ALIGN(8) { *(SORT(.ctors.*)) *(.ctors) } .init_array 0 : ALIGN(8) { *(SORT(.init_array.*)) *(.init_array) }