This series hunts the problems discovered after manual enabling of ARCH_WANT_LD_ORPHAN_WARN. Notably: - adds the missing PAGE_ALIGNED_DATA() section affecting VDSO placement (marked for stable); - stops blind catching of orphan text sections with .text.* directive; - properly stops .eh_frame section generation.
Compile and runtime tested on MIPS32R2 CPS board with no issues using two different toolkits: - Binutils 2.35.1, GCC 10.2.1 (with Alpine patches); - LLVM stack: 11.0.0 and from latest Git snapshot.
Since v4 [3]: - new: drop redundant .text.cps-vec creation and blind inclusion of orphan text sections via .text.* directive in vmlinux.lds.S; - don't assert SIZEOF(.rel.dyn) as it's reported that it may be not empty on certain machines and compilers (Thomas); - align GOT table like it's done for ARM64; - new: catch UBSAN's "unnamed data" sections in generic definitions when building with LD_DEAD_CODE_DATA_ELIMINATION; - collect Reviewed-bys (Kees, Nathan).
Since v3 [2]: - fix the third patch as GNU stack emits .rel.dyn into VDSO for some reason if .cfi_sections is specified.
Since v2 [1]: - stop discarding .eh_frame and just prevent it from generating (Kees); - drop redundant sections assertions (Fangrui); - place GOT table in .text instead of asserting as it's not empty when building with LLVM (Nathan); - catch compound literals in generic definitions when building with LD_DEAD_CODE_DATA_ELIMINATION (Kees); - collect two Reviewed-bys (Kees).
Since v1 [0]: - catch .got entries too as LLD may produce it (Nathan); - check for unwanted sections to be zero-sized instead of discarding (Fangrui).
[0] https://lore.kernel.org/linux-mips/20210104121729.46981-1-alobakin@pm.me [1] https://lore.kernel.org/linux-mips/20210106200713.31840-1-alobakin@pm.me [2] https://lore.kernel.org/linux-mips/20210107115120.281008-1-alobakin@pm.me [3] https://lore.kernel.org/linux-mips/20210107123331.354075-1-alobakin@pm.me
Alexander Lobakin (9): MIPS: vmlinux.lds.S: add missing PAGE_ALIGNED_DATA() section MIPS: CPS: don't create redundant .text.cps-vec section MIPS: vmlinux.lds.S: add ".gnu.attributes" to DISCARDS MIPS: properly stop .eh_frame generation MIPS: vmlinux.lds.S: explicitly catch .rel.dyn symbols MIPS: vmlinux.lds.S: explicitly declare .got table vmlinux.lds.h: catch compound literals into data and BSS vmlinux.lds.h: catch UBSAN's "unnamed data" into data MIPS: select ARCH_WANT_LD_ORPHAN_WARN
arch/mips/Kconfig | 1 + arch/mips/include/asm/asm.h | 18 ++++++++++++++++++ arch/mips/kernel/cps-vec.S | 1 - arch/mips/kernel/vmlinux.lds.S | 11 +++++++++-- include/asm-generic/vmlinux.lds.h | 6 +++--- 5 files changed, 31 insertions(+), 6 deletions(-)