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Subject[PATCH v5 mips-next 0/9] MIPS: vmlinux.lds.S sections fixes & cleanup
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(-)

--
2.30.0


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