Re: [PATCH v4 mips-next 0/7] MIPS: vmlinux.lds.S sections fixes & cleanup
From: Thomas Bogendoerfer Date: Sat, 9 Jan 2021 12:12:59 +0100 > On Thu, Jan 07, 2021 at 12:33:38PM +, Alexander Lobakin wrote: >> 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); >> - 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 10.2.0; >> - LLVM stack 11.0.0. >> >> 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-aloba...@pm.me >> [1] https://lore.kernel.org/linux-mips/20210106200713.31840-1-aloba...@pm.me >> [2] https://lore.kernel.org/linux-mips/20210107115120.281008-1-aloba...@pm.me >> >> Alexander Lobakin (7): >> MIPS: vmlinux.lds.S: add missing PAGE_ALIGNED_DATA() section >> MIPS: vmlinux.lds.S: add ".gnu.attributes" to DISCARDS >> MIPS: properly stop .eh_frame generation >> MIPS: vmlinux.lds.S: catch bad .rel.dyn at link time >> MIPS: vmlinux.lds.S: explicitly declare .got table >> vmlinux.lds.h: catch compound literals into data and BSS >> MIPS: select ARCH_WANT_LD_ORPHAN_WARN > > this breaks my builds: > > LD vmlinux.o > MODPOST vmlinux.symvers > MODINFO modules.builtin.modinfo > GEN modules.builtin > LD .tmp_vmlinux.kallsyms1 > mips64-linux-gnu-ld: Unexpected run-time relocations (.rel) detected! I think they should be handled as it's done for ARM64 [0]. Will do v5 soon. [0] https://elixir.bootlin.com/linux/v5.11-rc2/source/arch/arm64/kernel/vmlinux.lds.S#L219 > $ mips64-linux-gnu-ld --version > GNU ld version 2.27-3.fc24 > > $ mips64-linux-gnu-gcc --version > mips64-linux-gnu-gcc (GCC) 6.1.1 20160621 (Red Hat Cross 6.1.1-2) > > Thomas. Thanks, Alex > -- > Crap can work. Given enough thrust pigs will fly, but it's not necessarily a > good idea.[ RFC1925, 2.3 ]
Re: [PATCH v4 mips-next 0/7] MIPS: vmlinux.lds.S sections fixes & cleanup
On Thu, Jan 07, 2021 at 12:33:38PM +, Alexander Lobakin wrote: > 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); > - 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 10.2.0; > - LLVM stack 11.0.0. > > 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-aloba...@pm.me > [1] https://lore.kernel.org/linux-mips/20210106200713.31840-1-aloba...@pm.me > [2] https://lore.kernel.org/linux-mips/20210107115120.281008-1-aloba...@pm.me > > Alexander Lobakin (7): > MIPS: vmlinux.lds.S: add missing PAGE_ALIGNED_DATA() section > MIPS: vmlinux.lds.S: add ".gnu.attributes" to DISCARDS > MIPS: properly stop .eh_frame generation > MIPS: vmlinux.lds.S: catch bad .rel.dyn at link time > MIPS: vmlinux.lds.S: explicitly declare .got table > vmlinux.lds.h: catch compound literals into data and BSS > MIPS: select ARCH_WANT_LD_ORPHAN_WARN this breaks my builds: LD vmlinux.o MODPOST vmlinux.symvers MODINFO modules.builtin.modinfo GEN modules.builtin LD .tmp_vmlinux.kallsyms1 mips64-linux-gnu-ld: Unexpected run-time relocations (.rel) detected! $ mips64-linux-gnu-ld --version GNU ld version 2.27-3.fc24 $ mips64-linux-gnu-gcc --version mips64-linux-gnu-gcc (GCC) 6.1.1 20160621 (Red Hat Cross 6.1.1-2) Thomas. -- Crap can work. Given enough thrust pigs will fly, but it's not necessarily a good idea.[ RFC1925, 2.3 ]
Re: [PATCH v4 mips-next 0/7] MIPS: vmlinux.lds.S sections fixes & cleanup
On Thu, Jan 07, 2021 at 12:33:38PM +, Alexander Lobakin wrote: > 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); > - 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 10.2.0; > - LLVM stack 11.0.0. Nice! Thanks for hunting down the corner cases. :) -- Kees Cook
[PATCH v4 mips-next 0/7] 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); - 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 10.2.0; - LLVM stack 11.0.0. 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-aloba...@pm.me [1] https://lore.kernel.org/linux-mips/20210106200713.31840-1-aloba...@pm.me [2] https://lore.kernel.org/linux-mips/20210107115120.281008-1-aloba...@pm.me Alexander Lobakin (7): MIPS: vmlinux.lds.S: add missing PAGE_ALIGNED_DATA() section MIPS: vmlinux.lds.S: add ".gnu.attributes" to DISCARDS MIPS: properly stop .eh_frame generation MIPS: vmlinux.lds.S: catch bad .rel.dyn at link time MIPS: vmlinux.lds.S: explicitly declare .got table vmlinux.lds.h: catch compound literals into data and BSS MIPS: select ARCH_WANT_LD_ORPHAN_WARN arch/mips/Kconfig | 1 + arch/mips/include/asm/asm.h | 18 ++ arch/mips/kernel/vmlinux.lds.S| 15 ++- include/asm-generic/vmlinux.lds.h | 6 +++--- 4 files changed, 36 insertions(+), 4 deletions(-) -- 2.30.0
