* [PATCH v4 mips-next 0/7] MIPS: vmlinux.lds.S sections fixes & cleanup @ 2021-01-07 12:33 Alexander Lobakin 2021-01-07 12:34 ` [PATCH v4 mips-next 1/7] MIPS: vmlinux.lds.S: add missing PAGE_ALIGNED_DATA() section Alexander Lobakin ` (3 more replies) 0 siblings, 4 replies; 22+ messages in thread From: Alexander Lobakin @ 2021-01-07 12:33 UTC (permalink / raw) To: Thomas Bogendoerfer Cc: Arnd Bergmann, Kees Cook, Nathan Chancellor, Nick Desaulniers, Fangrui Song, Huacai Chen, Pei Huang, Jiaxun Yang, Alexander Lobakin, Sami Tolvanen, Ingo Molnar, Ralf Baechle, Corey Minyard, linux-mips, linux-kernel, linux-arch, stable, clang-built-linux 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-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 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 ^ permalink raw reply [flat|nested] 22+ messages in thread
* [PATCH v4 mips-next 1/7] MIPS: vmlinux.lds.S: add missing PAGE_ALIGNED_DATA() section 2021-01-07 12:33 [PATCH v4 mips-next 0/7] MIPS: vmlinux.lds.S sections fixes & cleanup Alexander Lobakin @ 2021-01-07 12:34 ` Alexander Lobakin 2021-01-07 12:34 ` [PATCH v4 mips-next 2/7] MIPS: vmlinux.lds.S: add ".gnu.attributes" to DISCARDS Alexander Lobakin ` (2 more replies) 2021-01-07 13:20 ` [PATCH v4 mips-next 4/7] MIPS: vmlinux.lds.S: catch bad .rel.dyn at link time Alexander Lobakin ` (2 subsequent siblings) 3 siblings, 3 replies; 22+ messages in thread From: Alexander Lobakin @ 2021-01-07 12:34 UTC (permalink / raw) To: Thomas Bogendoerfer Cc: Arnd Bergmann, Kees Cook, Nathan Chancellor, Nick Desaulniers, Fangrui Song, Huacai Chen, Pei Huang, Jiaxun Yang, Alexander Lobakin, Sami Tolvanen, Ingo Molnar, Ralf Baechle, Corey Minyard, linux-mips, linux-kernel, linux-arch, stable, clang-built-linux MIPS uses its own declaration of rwdata, and thus it should be kept in sync with the asm-generic one. Currently PAGE_ALIGNED_DATA() is missing from the linker script, which emits the following ld warnings: mips-alpine-linux-musl-ld: warning: orphan section `.data..page_aligned' from `arch/mips/kernel/vdso.o' being placed in section `.data..page_aligned' mips-alpine-linux-musl-ld: warning: orphan section `.data..page_aligned' from `arch/mips/vdso/vdso-image.o' being placed in section `.data..page_aligned' Add the necessary declaration, so the mentioned structures will be placed in vmlinux as intended: ffffffff80630580 D __end_once ffffffff80630580 D __start___dyndbg ffffffff80630580 D __start_once ffffffff80630580 D __stop___dyndbg ffffffff80634000 d mips_vdso_data ffffffff80638000 d vdso_data ffffffff80638580 D _gp ffffffff8063c000 T __init_begin ffffffff8063c000 D _edata ffffffff8063c000 T _sinittext -> ffffffff805a4000 D __end_init_task ffffffff805a4000 D __nosave_begin ffffffff805a4000 D __nosave_end ffffffff805a4000 d mips_vdso_data ffffffff805a8000 d vdso_data ffffffff805ac000 D mmlist_lock ffffffff805ac080 D tasklist_lock Fixes: ebb5e78cc634 ("MIPS: Initial implementation of a VDSO") Cc: stable@vger.kernel.org # 4.4+ Signed-off-by: Alexander Lobakin <alobakin@pm.me> Reviewed-by: Kees Cook <keescook@chromium.org> --- arch/mips/kernel/vmlinux.lds.S | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/mips/kernel/vmlinux.lds.S b/arch/mips/kernel/vmlinux.lds.S index 5e97e9d02f98..83e27a181206 100644 --- a/arch/mips/kernel/vmlinux.lds.S +++ b/arch/mips/kernel/vmlinux.lds.S @@ -90,6 +90,7 @@ SECTIONS INIT_TASK_DATA(THREAD_SIZE) NOSAVE_DATA + PAGE_ALIGNED_DATA(PAGE_SIZE) CACHELINE_ALIGNED_DATA(1 << CONFIG_MIPS_L1_CACHE_SHIFT) READ_MOSTLY_DATA(1 << CONFIG_MIPS_L1_CACHE_SHIFT) DATA_DATA -- 2.30.0 ^ permalink raw reply related [flat|nested] 22+ messages in thread
* [PATCH v4 mips-next 2/7] MIPS: vmlinux.lds.S: add ".gnu.attributes" to DISCARDS 2021-01-07 12:34 ` [PATCH v4 mips-next 1/7] MIPS: vmlinux.lds.S: add missing PAGE_ALIGNED_DATA() section Alexander Lobakin @ 2021-01-07 12:34 ` Alexander Lobakin 2021-01-08 21:12 ` Nathan Chancellor 2021-01-07 12:35 ` [PATCH v4 mips-next 3/7] MIPS: properly stop .eh_frame generation Alexander Lobakin 2021-01-08 21:10 ` [PATCH v4 mips-next 1/7] MIPS: vmlinux.lds.S: add missing PAGE_ALIGNED_DATA() section Nathan Chancellor 2 siblings, 1 reply; 22+ messages in thread From: Alexander Lobakin @ 2021-01-07 12:34 UTC (permalink / raw) To: Thomas Bogendoerfer Cc: Arnd Bergmann, Kees Cook, Nathan Chancellor, Nick Desaulniers, Fangrui Song, Huacai Chen, Pei Huang, Jiaxun Yang, Alexander Lobakin, Sami Tolvanen, Ingo Molnar, Ralf Baechle, Corey Minyard, linux-mips, linux-kernel, linux-arch, stable, clang-built-linux Discard GNU attributes (MIPS FP type, GNU Hash etc.) at link time as kernel doesn't use it at all. Solves a dozen of the following ld warnings (one per every file): mips-alpine-linux-musl-ld: warning: orphan section `.gnu.attributes' from `arch/mips/kernel/head.o' being placed in section `.gnu.attributes' mips-alpine-linux-musl-ld: warning: orphan section `.gnu.attributes' from `init/main.o' being placed in section `.gnu.attributes' Signed-off-by: Alexander Lobakin <alobakin@pm.me> --- arch/mips/kernel/vmlinux.lds.S | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/mips/kernel/vmlinux.lds.S b/arch/mips/kernel/vmlinux.lds.S index 83e27a181206..16468957cba2 100644 --- a/arch/mips/kernel/vmlinux.lds.S +++ b/arch/mips/kernel/vmlinux.lds.S @@ -221,6 +221,7 @@ SECTIONS /* ABI crap starts here */ *(.MIPS.abiflags) *(.MIPS.options) + *(.gnu.attributes) *(.options) *(.pdr) *(.reginfo) -- 2.30.0 ^ permalink raw reply related [flat|nested] 22+ messages in thread
* Re: [PATCH v4 mips-next 2/7] MIPS: vmlinux.lds.S: add ".gnu.attributes" to DISCARDS 2021-01-07 12:34 ` [PATCH v4 mips-next 2/7] MIPS: vmlinux.lds.S: add ".gnu.attributes" to DISCARDS Alexander Lobakin @ 2021-01-08 21:12 ` Nathan Chancellor 0 siblings, 0 replies; 22+ messages in thread From: Nathan Chancellor @ 2021-01-08 21:12 UTC (permalink / raw) To: Alexander Lobakin Cc: Thomas Bogendoerfer, Arnd Bergmann, Kees Cook, Nick Desaulniers, Fangrui Song, Huacai Chen, Pei Huang, Jiaxun Yang, Sami Tolvanen, Ingo Molnar, Ralf Baechle, Corey Minyard, linux-mips, linux-kernel, linux-arch, stable, clang-built-linux On Thu, Jan 07, 2021 at 12:34:53PM +0000, Alexander Lobakin wrote: > Discard GNU attributes (MIPS FP type, GNU Hash etc.) at link time > as kernel doesn't use it at all. > Solves a dozen of the following ld warnings (one per every file): > > mips-alpine-linux-musl-ld: warning: orphan section `.gnu.attributes' > from `arch/mips/kernel/head.o' being placed in section > `.gnu.attributes' > mips-alpine-linux-musl-ld: warning: orphan section `.gnu.attributes' > from `init/main.o' being placed in section `.gnu.attributes' > > Signed-off-by: Alexander Lobakin <alobakin@pm.me> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> > --- > arch/mips/kernel/vmlinux.lds.S | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/mips/kernel/vmlinux.lds.S b/arch/mips/kernel/vmlinux.lds.S > index 83e27a181206..16468957cba2 100644 > --- a/arch/mips/kernel/vmlinux.lds.S > +++ b/arch/mips/kernel/vmlinux.lds.S > @@ -221,6 +221,7 @@ SECTIONS > /* ABI crap starts here */ > *(.MIPS.abiflags) > *(.MIPS.options) > + *(.gnu.attributes) > *(.options) > *(.pdr) > *(.reginfo) > -- > 2.30.0 > > ^ permalink raw reply [flat|nested] 22+ messages in thread
* [PATCH v4 mips-next 3/7] MIPS: properly stop .eh_frame generation 2021-01-07 12:34 ` [PATCH v4 mips-next 1/7] MIPS: vmlinux.lds.S: add missing PAGE_ALIGNED_DATA() section Alexander Lobakin 2021-01-07 12:34 ` [PATCH v4 mips-next 2/7] MIPS: vmlinux.lds.S: add ".gnu.attributes" to DISCARDS Alexander Lobakin @ 2021-01-07 12:35 ` Alexander Lobakin 2021-01-07 21:48 ` Kees Cook 2021-01-08 21:16 ` Nathan Chancellor 2021-01-08 21:10 ` [PATCH v4 mips-next 1/7] MIPS: vmlinux.lds.S: add missing PAGE_ALIGNED_DATA() section Nathan Chancellor 2 siblings, 2 replies; 22+ messages in thread From: Alexander Lobakin @ 2021-01-07 12:35 UTC (permalink / raw) To: Thomas Bogendoerfer Cc: Arnd Bergmann, Kees Cook, Nathan Chancellor, Nick Desaulniers, Fangrui Song, Huacai Chen, Pei Huang, Jiaxun Yang, Alexander Lobakin, Sami Tolvanen, Ingo Molnar, Ralf Baechle, Corey Minyard, linux-mips, linux-kernel, linux-arch, stable, clang-built-linux Commit 866b6a89c6d1 ("MIPS: Add DWARF unwinding to assembly") added -fno-asynchronous-unwind-tables to KBUILD_CFLAGS to prevent compiler from emitting .eh_frame symbols. However, as MIPS heavily uses CFI, that's not enough. Use the approach taken for x86 (as it also uses CFI) and explicitly put CFI symbols into the .debug_frame section (except for VDSO). This allows us to drop .eh_frame from DISCARDS as it's no longer being generated. Fixes: 866b6a89c6d1 ("MIPS: Add DWARF unwinding to assembly") Suggested-by: Kees Cook <keescook@chromium.org> Signed-off-by: Alexander Lobakin <alobakin@pm.me> --- arch/mips/include/asm/asm.h | 18 ++++++++++++++++++ arch/mips/kernel/vmlinux.lds.S | 1 - 2 files changed, 18 insertions(+), 1 deletion(-) diff --git a/arch/mips/include/asm/asm.h b/arch/mips/include/asm/asm.h index 3682d1a0bb80..908f6d6ae24b 100644 --- a/arch/mips/include/asm/asm.h +++ b/arch/mips/include/asm/asm.h @@ -20,10 +20,27 @@ #include <asm/sgidefs.h> #include <asm/asm-eva.h> +#ifndef __VDSO__ +/* + * Emit CFI data in .debug_frame sections, not .eh_frame sections. + * We don't do DWARF unwinding at runtime, so only the offline DWARF + * information is useful to anyone. Note we should change this if we + * ever decide to enable DWARF unwinding at runtime. + */ +#define CFI_SECTIONS .cfi_sections .debug_frame +#else + /* + * For the vDSO, emit both runtime unwind information and debug + * symbols for the .dbg file. + */ +#define CFI_SECTIONS +#endif + /* * LEAF - declare leaf routine */ #define LEAF(symbol) \ + CFI_SECTIONS; \ .globl symbol; \ .align 2; \ .type symbol, @function; \ @@ -36,6 +53,7 @@ symbol: .frame sp, 0, ra; \ * NESTED - declare nested routine entry point */ #define NESTED(symbol, framesize, rpc) \ + CFI_SECTIONS; \ .globl symbol; \ .align 2; \ .type symbol, @function; \ diff --git a/arch/mips/kernel/vmlinux.lds.S b/arch/mips/kernel/vmlinux.lds.S index 16468957cba2..0f4e46ea4458 100644 --- a/arch/mips/kernel/vmlinux.lds.S +++ b/arch/mips/kernel/vmlinux.lds.S @@ -225,6 +225,5 @@ SECTIONS *(.options) *(.pdr) *(.reginfo) - *(.eh_frame) } } -- 2.30.0 ^ permalink raw reply related [flat|nested] 22+ messages in thread
* Re: [PATCH v4 mips-next 3/7] MIPS: properly stop .eh_frame generation 2021-01-07 12:35 ` [PATCH v4 mips-next 3/7] MIPS: properly stop .eh_frame generation Alexander Lobakin @ 2021-01-07 21:48 ` Kees Cook 2021-01-08 21:16 ` Nathan Chancellor 1 sibling, 0 replies; 22+ messages in thread From: Kees Cook @ 2021-01-07 21:48 UTC (permalink / raw) To: Alexander Lobakin Cc: Thomas Bogendoerfer, Arnd Bergmann, Nathan Chancellor, Nick Desaulniers, Fangrui Song, Huacai Chen, Pei Huang, Jiaxun Yang, Sami Tolvanen, Ingo Molnar, Ralf Baechle, Corey Minyard, linux-mips, linux-kernel, linux-arch, stable, clang-built-linux On Thu, Jan 07, 2021 at 12:35:01PM +0000, Alexander Lobakin wrote: > Commit 866b6a89c6d1 ("MIPS: Add DWARF unwinding to assembly") added > -fno-asynchronous-unwind-tables to KBUILD_CFLAGS to prevent compiler > from emitting .eh_frame symbols. > However, as MIPS heavily uses CFI, that's not enough. Use the > approach taken for x86 (as it also uses CFI) and explicitly put CFI > symbols into the .debug_frame section (except for VDSO). > This allows us to drop .eh_frame from DISCARDS as it's no longer > being generated. > > Fixes: 866b6a89c6d1 ("MIPS: Add DWARF unwinding to assembly") > Suggested-by: Kees Cook <keescook@chromium.org> > Signed-off-by: Alexander Lobakin <alobakin@pm.me> Reviewed-by: Kees Cook <keescook@chromium.org> -- Kees Cook ^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH v4 mips-next 3/7] MIPS: properly stop .eh_frame generation 2021-01-07 12:35 ` [PATCH v4 mips-next 3/7] MIPS: properly stop .eh_frame generation Alexander Lobakin 2021-01-07 21:48 ` Kees Cook @ 2021-01-08 21:16 ` Nathan Chancellor 1 sibling, 0 replies; 22+ messages in thread From: Nathan Chancellor @ 2021-01-08 21:16 UTC (permalink / raw) To: Alexander Lobakin Cc: Thomas Bogendoerfer, Arnd Bergmann, Kees Cook, Nick Desaulniers, Fangrui Song, Huacai Chen, Pei Huang, Jiaxun Yang, Sami Tolvanen, Ingo Molnar, Ralf Baechle, Corey Minyard, linux-mips, linux-kernel, linux-arch, stable, clang-built-linux On Thu, Jan 07, 2021 at 12:35:01PM +0000, Alexander Lobakin wrote: > Commit 866b6a89c6d1 ("MIPS: Add DWARF unwinding to assembly") added > -fno-asynchronous-unwind-tables to KBUILD_CFLAGS to prevent compiler > from emitting .eh_frame symbols. > However, as MIPS heavily uses CFI, that's not enough. Use the > approach taken for x86 (as it also uses CFI) and explicitly put CFI > symbols into the .debug_frame section (except for VDSO). > This allows us to drop .eh_frame from DISCARDS as it's no longer > being generated. > > Fixes: 866b6a89c6d1 ("MIPS: Add DWARF unwinding to assembly") > Suggested-by: Kees Cook <keescook@chromium.org> > Signed-off-by: Alexander Lobakin <alobakin@pm.me> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> > --- > arch/mips/include/asm/asm.h | 18 ++++++++++++++++++ > arch/mips/kernel/vmlinux.lds.S | 1 - > 2 files changed, 18 insertions(+), 1 deletion(-) > > diff --git a/arch/mips/include/asm/asm.h b/arch/mips/include/asm/asm.h > index 3682d1a0bb80..908f6d6ae24b 100644 > --- a/arch/mips/include/asm/asm.h > +++ b/arch/mips/include/asm/asm.h > @@ -20,10 +20,27 @@ > #include <asm/sgidefs.h> > #include <asm/asm-eva.h> > > +#ifndef __VDSO__ > +/* > + * Emit CFI data in .debug_frame sections, not .eh_frame sections. > + * We don't do DWARF unwinding at runtime, so only the offline DWARF > + * information is useful to anyone. Note we should change this if we > + * ever decide to enable DWARF unwinding at runtime. > + */ > +#define CFI_SECTIONS .cfi_sections .debug_frame > +#else > + /* > + * For the vDSO, emit both runtime unwind information and debug > + * symbols for the .dbg file. > + */ > +#define CFI_SECTIONS > +#endif > + > /* > * LEAF - declare leaf routine > */ > #define LEAF(symbol) \ > + CFI_SECTIONS; \ > .globl symbol; \ > .align 2; \ > .type symbol, @function; \ > @@ -36,6 +53,7 @@ symbol: .frame sp, 0, ra; \ > * NESTED - declare nested routine entry point > */ > #define NESTED(symbol, framesize, rpc) \ > + CFI_SECTIONS; \ > .globl symbol; \ > .align 2; \ > .type symbol, @function; \ > diff --git a/arch/mips/kernel/vmlinux.lds.S b/arch/mips/kernel/vmlinux.lds.S > index 16468957cba2..0f4e46ea4458 100644 > --- a/arch/mips/kernel/vmlinux.lds.S > +++ b/arch/mips/kernel/vmlinux.lds.S > @@ -225,6 +225,5 @@ SECTIONS > *(.options) > *(.pdr) > *(.reginfo) > - *(.eh_frame) > } > } > -- > 2.30.0 > > ^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH v4 mips-next 1/7] MIPS: vmlinux.lds.S: add missing PAGE_ALIGNED_DATA() section 2021-01-07 12:34 ` [PATCH v4 mips-next 1/7] MIPS: vmlinux.lds.S: add missing PAGE_ALIGNED_DATA() section Alexander Lobakin 2021-01-07 12:34 ` [PATCH v4 mips-next 2/7] MIPS: vmlinux.lds.S: add ".gnu.attributes" to DISCARDS Alexander Lobakin 2021-01-07 12:35 ` [PATCH v4 mips-next 3/7] MIPS: properly stop .eh_frame generation Alexander Lobakin @ 2021-01-08 21:10 ` Nathan Chancellor 2 siblings, 0 replies; 22+ messages in thread From: Nathan Chancellor @ 2021-01-08 21:10 UTC (permalink / raw) To: Alexander Lobakin Cc: Thomas Bogendoerfer, Arnd Bergmann, Kees Cook, Nick Desaulniers, Fangrui Song, Huacai Chen, Pei Huang, Jiaxun Yang, Sami Tolvanen, Ingo Molnar, Ralf Baechle, Corey Minyard, linux-mips, linux-kernel, linux-arch, stable, clang-built-linux On Thu, Jan 07, 2021 at 12:34:47PM +0000, Alexander Lobakin wrote: > MIPS uses its own declaration of rwdata, and thus it should be kept > in sync with the asm-generic one. Currently PAGE_ALIGNED_DATA() is > missing from the linker script, which emits the following ld > warnings: > > mips-alpine-linux-musl-ld: warning: orphan section > `.data..page_aligned' from `arch/mips/kernel/vdso.o' being placed > in section `.data..page_aligned' > mips-alpine-linux-musl-ld: warning: orphan section > `.data..page_aligned' from `arch/mips/vdso/vdso-image.o' being placed > in section `.data..page_aligned' > > Add the necessary declaration, so the mentioned structures will be > placed in vmlinux as intended: > > ffffffff80630580 D __end_once > ffffffff80630580 D __start___dyndbg > ffffffff80630580 D __start_once > ffffffff80630580 D __stop___dyndbg > ffffffff80634000 d mips_vdso_data > ffffffff80638000 d vdso_data > ffffffff80638580 D _gp > ffffffff8063c000 T __init_begin > ffffffff8063c000 D _edata > ffffffff8063c000 T _sinittext > > -> > > ffffffff805a4000 D __end_init_task > ffffffff805a4000 D __nosave_begin > ffffffff805a4000 D __nosave_end > ffffffff805a4000 d mips_vdso_data > ffffffff805a8000 d vdso_data > ffffffff805ac000 D mmlist_lock > ffffffff805ac080 D tasklist_lock > > Fixes: ebb5e78cc634 ("MIPS: Initial implementation of a VDSO") > Cc: stable@vger.kernel.org # 4.4+ > Signed-off-by: Alexander Lobakin <alobakin@pm.me> > Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> > --- > arch/mips/kernel/vmlinux.lds.S | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/mips/kernel/vmlinux.lds.S b/arch/mips/kernel/vmlinux.lds.S > index 5e97e9d02f98..83e27a181206 100644 > --- a/arch/mips/kernel/vmlinux.lds.S > +++ b/arch/mips/kernel/vmlinux.lds.S > @@ -90,6 +90,7 @@ SECTIONS > > INIT_TASK_DATA(THREAD_SIZE) > NOSAVE_DATA > + PAGE_ALIGNED_DATA(PAGE_SIZE) > CACHELINE_ALIGNED_DATA(1 << CONFIG_MIPS_L1_CACHE_SHIFT) > READ_MOSTLY_DATA(1 << CONFIG_MIPS_L1_CACHE_SHIFT) > DATA_DATA > -- > 2.30.0 > > ^ permalink raw reply [flat|nested] 22+ messages in thread
* [PATCH v4 mips-next 4/7] MIPS: vmlinux.lds.S: catch bad .rel.dyn at link time 2021-01-07 12:33 [PATCH v4 mips-next 0/7] MIPS: vmlinux.lds.S sections fixes & cleanup Alexander Lobakin 2021-01-07 12:34 ` [PATCH v4 mips-next 1/7] MIPS: vmlinux.lds.S: add missing PAGE_ALIGNED_DATA() section Alexander Lobakin @ 2021-01-07 13:20 ` Alexander Lobakin 2021-01-07 13:20 ` [PATCH v4 mips-next 5/7] MIPS: vmlinux.lds.S: explicitly declare .got table Alexander Lobakin ` (4 more replies) 2021-01-07 21:51 ` [PATCH v4 mips-next 0/7] MIPS: vmlinux.lds.S sections fixes & cleanup Kees Cook 2021-01-09 11:12 ` Thomas Bogendoerfer 3 siblings, 5 replies; 22+ messages in thread From: Alexander Lobakin @ 2021-01-07 13:20 UTC (permalink / raw) To: Thomas Bogendoerfer Cc: Arnd Bergmann, Kees Cook, Nathan Chancellor, Nick Desaulniers, Fangrui Song, Huacai Chen, Pei Huang, Jiaxun Yang, Alexander Lobakin, Sami Tolvanen, Ingo Molnar, Ralf Baechle, Corey Minyard, linux-mips, linux-kernel, linux-arch, stable, clang-built-linux Catch any symbols placed in .rel.dyn and check for these sections to be zero-sized at link time. Eliminates following ld warning: mips-alpine-linux-musl-ld: warning: orphan section `.rel.dyn' from `init/main.o' being placed in section `.rel.dyn' Adopted from x86/kernel/vmlinux.lds.S. Suggested-by: Fangrui Song <maskray@google.com> Signed-off-by: Alexander Lobakin <alobakin@pm.me> --- arch/mips/kernel/vmlinux.lds.S | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/arch/mips/kernel/vmlinux.lds.S b/arch/mips/kernel/vmlinux.lds.S index 0f4e46ea4458..0f736d60d43e 100644 --- a/arch/mips/kernel/vmlinux.lds.S +++ b/arch/mips/kernel/vmlinux.lds.S @@ -226,4 +226,15 @@ SECTIONS *(.pdr) *(.reginfo) } + + /* + * Sections that should stay zero sized, which is safer to + * explicitly check instead of blindly discarding. + */ + + .rel.dyn : { + *(.rel.*) + *(.rel_*) + } + ASSERT(SIZEOF(.rel.dyn) == 0, "Unexpected run-time relocations (.rel) detected!") } -- 2.30.0 ^ permalink raw reply related [flat|nested] 22+ messages in thread
* [PATCH v4 mips-next 5/7] MIPS: vmlinux.lds.S: explicitly declare .got table 2021-01-07 13:20 ` [PATCH v4 mips-next 4/7] MIPS: vmlinux.lds.S: catch bad .rel.dyn at link time Alexander Lobakin @ 2021-01-07 13:20 ` Alexander Lobakin 2021-01-07 21:49 ` Kees Cook 2021-01-08 21:17 ` Nathan Chancellor 2021-01-07 13:20 ` [PATCH v4 mips-next 6/7] vmlinux.lds.h: catch compound literals into data and BSS Alexander Lobakin ` (3 subsequent siblings) 4 siblings, 2 replies; 22+ messages in thread From: Alexander Lobakin @ 2021-01-07 13:20 UTC (permalink / raw) To: Thomas Bogendoerfer Cc: Arnd Bergmann, Kees Cook, Nathan Chancellor, Nick Desaulniers, Fangrui Song, Huacai Chen, Pei Huang, Jiaxun Yang, Alexander Lobakin, Sami Tolvanen, Ingo Molnar, Ralf Baechle, Corey Minyard, linux-mips, linux-kernel, linux-arch, stable, clang-built-linux LLVM stack generates GOT table when building the kernel: ld.lld: warning: <internal>:(.got) is being placed in '.got' According to the debug assertions, it's not zero-sized and thus can't be handled the same way as .rel.dyn (like it's done for x86). Use the ARM/ARM64 path here and place it at the end of .text section. Reported-by: Nathan Chancellor <natechancellor@gmail.com> Signed-off-by: Alexander Lobakin <alobakin@pm.me> --- arch/mips/kernel/vmlinux.lds.S | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/mips/kernel/vmlinux.lds.S b/arch/mips/kernel/vmlinux.lds.S index 0f736d60d43e..4709959f6985 100644 --- a/arch/mips/kernel/vmlinux.lds.S +++ b/arch/mips/kernel/vmlinux.lds.S @@ -69,6 +69,7 @@ SECTIONS *(.text.*) *(.fixup) *(.gnu.warning) + *(.got) } :text = 0 _etext = .; /* End of text section */ -- 2.30.0 ^ permalink raw reply related [flat|nested] 22+ messages in thread
* Re: [PATCH v4 mips-next 5/7] MIPS: vmlinux.lds.S: explicitly declare .got table 2021-01-07 13:20 ` [PATCH v4 mips-next 5/7] MIPS: vmlinux.lds.S: explicitly declare .got table Alexander Lobakin @ 2021-01-07 21:49 ` Kees Cook 2021-01-08 21:17 ` Nathan Chancellor 1 sibling, 0 replies; 22+ messages in thread From: Kees Cook @ 2021-01-07 21:49 UTC (permalink / raw) To: Alexander Lobakin Cc: Thomas Bogendoerfer, Arnd Bergmann, Nathan Chancellor, Nick Desaulniers, Fangrui Song, Huacai Chen, Pei Huang, Jiaxun Yang, Sami Tolvanen, Ingo Molnar, Ralf Baechle, Corey Minyard, linux-mips, linux-kernel, linux-arch, stable, clang-built-linux On Thu, Jan 07, 2021 at 01:20:49PM +0000, Alexander Lobakin wrote: > LLVM stack generates GOT table when building the kernel: > > ld.lld: warning: <internal>:(.got) is being placed in '.got' > > According to the debug assertions, it's not zero-sized and thus > can't be handled the same way as .rel.dyn (like it's done for x86). > Use the ARM/ARM64 path here and place it at the end of .text section. > > Reported-by: Nathan Chancellor <natechancellor@gmail.com> > Signed-off-by: Alexander Lobakin <alobakin@pm.me> Reviewed-by: Kees Cook <keescook@chromium.org> -- Kees Cook ^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH v4 mips-next 5/7] MIPS: vmlinux.lds.S: explicitly declare .got table 2021-01-07 13:20 ` [PATCH v4 mips-next 5/7] MIPS: vmlinux.lds.S: explicitly declare .got table Alexander Lobakin 2021-01-07 21:49 ` Kees Cook @ 2021-01-08 21:17 ` Nathan Chancellor 1 sibling, 0 replies; 22+ messages in thread From: Nathan Chancellor @ 2021-01-08 21:17 UTC (permalink / raw) To: Alexander Lobakin Cc: Thomas Bogendoerfer, Arnd Bergmann, Kees Cook, Nick Desaulniers, Fangrui Song, Huacai Chen, Pei Huang, Jiaxun Yang, Sami Tolvanen, Ingo Molnar, Ralf Baechle, Corey Minyard, linux-mips, linux-kernel, linux-arch, stable, clang-built-linux On Thu, Jan 07, 2021 at 01:20:49PM +0000, Alexander Lobakin wrote: > LLVM stack generates GOT table when building the kernel: > > ld.lld: warning: <internal>:(.got) is being placed in '.got' > > According to the debug assertions, it's not zero-sized and thus > can't be handled the same way as .rel.dyn (like it's done for x86). > Use the ARM/ARM64 path here and place it at the end of .text section. > > Reported-by: Nathan Chancellor <natechancellor@gmail.com> > Signed-off-by: Alexander Lobakin <alobakin@pm.me> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> > --- > arch/mips/kernel/vmlinux.lds.S | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/mips/kernel/vmlinux.lds.S b/arch/mips/kernel/vmlinux.lds.S > index 0f736d60d43e..4709959f6985 100644 > --- a/arch/mips/kernel/vmlinux.lds.S > +++ b/arch/mips/kernel/vmlinux.lds.S > @@ -69,6 +69,7 @@ SECTIONS > *(.text.*) > *(.fixup) > *(.gnu.warning) > + *(.got) > } :text = 0 > _etext = .; /* End of text section */ > > -- > 2.30.0 > > ^ permalink raw reply [flat|nested] 22+ messages in thread
* [PATCH v4 mips-next 6/7] vmlinux.lds.h: catch compound literals into data and BSS 2021-01-07 13:20 ` [PATCH v4 mips-next 4/7] MIPS: vmlinux.lds.S: catch bad .rel.dyn at link time Alexander Lobakin 2021-01-07 13:20 ` [PATCH v4 mips-next 5/7] MIPS: vmlinux.lds.S: explicitly declare .got table Alexander Lobakin @ 2021-01-07 13:20 ` Alexander Lobakin 2021-01-07 21:51 ` Kees Cook 2021-01-08 21:19 ` Nathan Chancellor 2021-01-07 13:21 ` [PATCH v4 mips-next 7/7] MIPS: select ARCH_WANT_LD_ORPHAN_WARN Alexander Lobakin ` (2 subsequent siblings) 4 siblings, 2 replies; 22+ messages in thread From: Alexander Lobakin @ 2021-01-07 13:20 UTC (permalink / raw) To: Thomas Bogendoerfer Cc: Arnd Bergmann, Kees Cook, Nathan Chancellor, Nick Desaulniers, Fangrui Song, Huacai Chen, Pei Huang, Jiaxun Yang, Alexander Lobakin, Sami Tolvanen, Ingo Molnar, Ralf Baechle, Corey Minyard, linux-mips, linux-kernel, linux-arch, stable, clang-built-linux When building kernel with LD_DEAD_CODE_DATA_ELIMINATION, LLVM stack generates separate sections for compound literals, just like in case with enabled LTO [0]: ld.lld: warning: drivers/built-in.a(mtd/nand/spi/gigadevice.o): (.data..compoundliteral.14) is being placed in '.data..compoundliteral.14' ld.lld: warning: drivers/built-in.a(mtd/nand/spi/gigadevice.o): (.data..compoundliteral.15) is being placed in '.data..compoundliteral.15' ld.lld: warning: drivers/built-in.a(mtd/nand/spi/gigadevice.o): (.data..compoundliteral.16) is being placed in '.data..compoundliteral.16' ld.lld: warning: drivers/built-in.a(mtd/nand/spi/gigadevice.o): (.data..compoundliteral.17) is being placed in '.data..compoundliteral.17' [...] Handle this by adding the related sections to generic definitions as suggested by Sami [0]. [0] https://lore.kernel.org/lkml/20201211184633.3213045-3-samitolvanen@google.com Suggested-by: Kees Cook <keescook@chromium.org> Signed-off-by: Alexander Lobakin <alobakin@pm.me> --- include/asm-generic/vmlinux.lds.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index b2b3d81b1535..5f2f5b1db84f 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -95,10 +95,10 @@ */ #ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION #define TEXT_MAIN .text .text.[0-9a-zA-Z_]* -#define DATA_MAIN .data .data.[0-9a-zA-Z_]* .data..LPBX* +#define DATA_MAIN .data .data.[0-9a-zA-Z_]* .data..L* .data..compoundliteral* #define SDATA_MAIN .sdata .sdata.[0-9a-zA-Z_]* -#define RODATA_MAIN .rodata .rodata.[0-9a-zA-Z_]* -#define BSS_MAIN .bss .bss.[0-9a-zA-Z_]* +#define RODATA_MAIN .rodata .rodata.[0-9a-zA-Z_]* .rodata..L* +#define BSS_MAIN .bss .bss.[0-9a-zA-Z_]* .bss..compoundliteral* #define SBSS_MAIN .sbss .sbss.[0-9a-zA-Z_]* #else #define TEXT_MAIN .text -- 2.30.0 ^ permalink raw reply related [flat|nested] 22+ messages in thread
* Re: [PATCH v4 mips-next 6/7] vmlinux.lds.h: catch compound literals into data and BSS 2021-01-07 13:20 ` [PATCH v4 mips-next 6/7] vmlinux.lds.h: catch compound literals into data and BSS Alexander Lobakin @ 2021-01-07 21:51 ` Kees Cook 2021-01-08 21:19 ` Nathan Chancellor 1 sibling, 0 replies; 22+ messages in thread From: Kees Cook @ 2021-01-07 21:51 UTC (permalink / raw) To: Alexander Lobakin Cc: Thomas Bogendoerfer, Arnd Bergmann, Nathan Chancellor, Nick Desaulniers, Fangrui Song, Huacai Chen, Pei Huang, Jiaxun Yang, Sami Tolvanen, Ingo Molnar, Ralf Baechle, Corey Minyard, linux-mips, linux-kernel, linux-arch, stable, clang-built-linux On Thu, Jan 07, 2021 at 01:20:55PM +0000, Alexander Lobakin wrote: > When building kernel with LD_DEAD_CODE_DATA_ELIMINATION, LLVM stack > generates separate sections for compound literals, just like in case > with enabled LTO [0]: > > ld.lld: warning: drivers/built-in.a(mtd/nand/spi/gigadevice.o): > (.data..compoundliteral.14) is being placed in > '.data..compoundliteral.14' > ld.lld: warning: drivers/built-in.a(mtd/nand/spi/gigadevice.o): > (.data..compoundliteral.15) is being placed in > '.data..compoundliteral.15' > ld.lld: warning: drivers/built-in.a(mtd/nand/spi/gigadevice.o): > (.data..compoundliteral.16) is being placed in > '.data..compoundliteral.16' > ld.lld: warning: drivers/built-in.a(mtd/nand/spi/gigadevice.o): > (.data..compoundliteral.17) is being placed in > '.data..compoundliteral.17' > > [...] > > Handle this by adding the related sections to generic definitions > as suggested by Sami [0]. > > [0] https://lore.kernel.org/lkml/20201211184633.3213045-3-samitolvanen@google.com > > Suggested-by: Kees Cook <keescook@chromium.org> > Signed-off-by: Alexander Lobakin <alobakin@pm.me> Suggested-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> -- Kees Cook ^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH v4 mips-next 6/7] vmlinux.lds.h: catch compound literals into data and BSS 2021-01-07 13:20 ` [PATCH v4 mips-next 6/7] vmlinux.lds.h: catch compound literals into data and BSS Alexander Lobakin 2021-01-07 21:51 ` Kees Cook @ 2021-01-08 21:19 ` Nathan Chancellor 1 sibling, 0 replies; 22+ messages in thread From: Nathan Chancellor @ 2021-01-08 21:19 UTC (permalink / raw) To: Alexander Lobakin Cc: Thomas Bogendoerfer, Arnd Bergmann, Kees Cook, Nick Desaulniers, Fangrui Song, Huacai Chen, Pei Huang, Jiaxun Yang, Sami Tolvanen, Ingo Molnar, Ralf Baechle, Corey Minyard, linux-mips, linux-kernel, linux-arch, stable, clang-built-linux On Thu, Jan 07, 2021 at 01:20:55PM +0000, Alexander Lobakin wrote: > When building kernel with LD_DEAD_CODE_DATA_ELIMINATION, LLVM stack > generates separate sections for compound literals, just like in case > with enabled LTO [0]: > > ld.lld: warning: drivers/built-in.a(mtd/nand/spi/gigadevice.o): > (.data..compoundliteral.14) is being placed in > '.data..compoundliteral.14' > ld.lld: warning: drivers/built-in.a(mtd/nand/spi/gigadevice.o): > (.data..compoundliteral.15) is being placed in > '.data..compoundliteral.15' > ld.lld: warning: drivers/built-in.a(mtd/nand/spi/gigadevice.o): > (.data..compoundliteral.16) is being placed in > '.data..compoundliteral.16' > ld.lld: warning: drivers/built-in.a(mtd/nand/spi/gigadevice.o): > (.data..compoundliteral.17) is being placed in > '.data..compoundliteral.17' > > [...] > > Handle this by adding the related sections to generic definitions > as suggested by Sami [0]. > > [0] https://lore.kernel.org/lkml/20201211184633.3213045-3-samitolvanen@google.com > > Suggested-by: Kees Cook <keescook@chromium.org> > Signed-off-by: Alexander Lobakin <alobakin@pm.me> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> > --- > include/asm-generic/vmlinux.lds.h | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h > index b2b3d81b1535..5f2f5b1db84f 100644 > --- a/include/asm-generic/vmlinux.lds.h > +++ b/include/asm-generic/vmlinux.lds.h > @@ -95,10 +95,10 @@ > */ > #ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION > #define TEXT_MAIN .text .text.[0-9a-zA-Z_]* > -#define DATA_MAIN .data .data.[0-9a-zA-Z_]* .data..LPBX* > +#define DATA_MAIN .data .data.[0-9a-zA-Z_]* .data..L* .data..compoundliteral* > #define SDATA_MAIN .sdata .sdata.[0-9a-zA-Z_]* > -#define RODATA_MAIN .rodata .rodata.[0-9a-zA-Z_]* > -#define BSS_MAIN .bss .bss.[0-9a-zA-Z_]* > +#define RODATA_MAIN .rodata .rodata.[0-9a-zA-Z_]* .rodata..L* > +#define BSS_MAIN .bss .bss.[0-9a-zA-Z_]* .bss..compoundliteral* > #define SBSS_MAIN .sbss .sbss.[0-9a-zA-Z_]* > #else > #define TEXT_MAIN .text > -- > 2.30.0 > > ^ permalink raw reply [flat|nested] 22+ messages in thread
* [PATCH v4 mips-next 7/7] MIPS: select ARCH_WANT_LD_ORPHAN_WARN 2021-01-07 13:20 ` [PATCH v4 mips-next 4/7] MIPS: vmlinux.lds.S: catch bad .rel.dyn at link time Alexander Lobakin 2021-01-07 13:20 ` [PATCH v4 mips-next 5/7] MIPS: vmlinux.lds.S: explicitly declare .got table Alexander Lobakin 2021-01-07 13:20 ` [PATCH v4 mips-next 6/7] vmlinux.lds.h: catch compound literals into data and BSS Alexander Lobakin @ 2021-01-07 13:21 ` Alexander Lobakin 2021-01-08 21:19 ` Nathan Chancellor 2021-01-07 21:48 ` [PATCH v4 mips-next 4/7] MIPS: vmlinux.lds.S: catch bad .rel.dyn at link time Kees Cook 2021-01-08 21:17 ` Nathan Chancellor 4 siblings, 1 reply; 22+ messages in thread From: Alexander Lobakin @ 2021-01-07 13:21 UTC (permalink / raw) To: Thomas Bogendoerfer Cc: Arnd Bergmann, Kees Cook, Nathan Chancellor, Nick Desaulniers, Fangrui Song, Huacai Chen, Pei Huang, Jiaxun Yang, Alexander Lobakin, Sami Tolvanen, Ingo Molnar, Ralf Baechle, Corey Minyard, linux-mips, linux-kernel, linux-arch, stable, clang-built-linux Now, after that all the sections are explicitly described and declared in vmlinux.lds.S, we can enable ld orphan warnings to prevent from missing any new sections in future. Signed-off-by: Alexander Lobakin <alobakin@pm.me> Reviewed-by: Kees Cook <keescook@chromium.org> --- arch/mips/Kconfig | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index d68df1febd25..d3e64cc0932b 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -18,6 +18,7 @@ config MIPS select ARCH_USE_QUEUED_SPINLOCKS select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU select ARCH_WANT_IPC_PARSE_VERSION + select ARCH_WANT_LD_ORPHAN_WARN select BUILDTIME_TABLE_SORT select CLONE_BACKWARDS select CPU_NO_EFFICIENT_FFS if (TARGET_ISA_REV < 1) -- 2.30.0 ^ permalink raw reply related [flat|nested] 22+ messages in thread
* Re: [PATCH v4 mips-next 7/7] MIPS: select ARCH_WANT_LD_ORPHAN_WARN 2021-01-07 13:21 ` [PATCH v4 mips-next 7/7] MIPS: select ARCH_WANT_LD_ORPHAN_WARN Alexander Lobakin @ 2021-01-08 21:19 ` Nathan Chancellor 0 siblings, 0 replies; 22+ messages in thread From: Nathan Chancellor @ 2021-01-08 21:19 UTC (permalink / raw) To: Alexander Lobakin Cc: Thomas Bogendoerfer, Arnd Bergmann, Kees Cook, Nick Desaulniers, Fangrui Song, Huacai Chen, Pei Huang, Jiaxun Yang, Sami Tolvanen, Ingo Molnar, Ralf Baechle, Corey Minyard, linux-mips, linux-kernel, linux-arch, stable, clang-built-linux On Thu, Jan 07, 2021 at 01:21:02PM +0000, Alexander Lobakin wrote: > Now, after that all the sections are explicitly described and > declared in vmlinux.lds.S, we can enable ld orphan warnings to > prevent from missing any new sections in future. > > Signed-off-by: Alexander Lobakin <alobakin@pm.me> > Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> > --- > arch/mips/Kconfig | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig > index d68df1febd25..d3e64cc0932b 100644 > --- a/arch/mips/Kconfig > +++ b/arch/mips/Kconfig > @@ -18,6 +18,7 @@ config MIPS > select ARCH_USE_QUEUED_SPINLOCKS > select ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT if MMU > select ARCH_WANT_IPC_PARSE_VERSION > + select ARCH_WANT_LD_ORPHAN_WARN > select BUILDTIME_TABLE_SORT > select CLONE_BACKWARDS > select CPU_NO_EFFICIENT_FFS if (TARGET_ISA_REV < 1) > -- > 2.30.0 > > ^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH v4 mips-next 4/7] MIPS: vmlinux.lds.S: catch bad .rel.dyn at link time 2021-01-07 13:20 ` [PATCH v4 mips-next 4/7] MIPS: vmlinux.lds.S: catch bad .rel.dyn at link time Alexander Lobakin ` (2 preceding siblings ...) 2021-01-07 13:21 ` [PATCH v4 mips-next 7/7] MIPS: select ARCH_WANT_LD_ORPHAN_WARN Alexander Lobakin @ 2021-01-07 21:48 ` Kees Cook 2021-01-08 21:17 ` Nathan Chancellor 4 siblings, 0 replies; 22+ messages in thread From: Kees Cook @ 2021-01-07 21:48 UTC (permalink / raw) To: Alexander Lobakin Cc: Thomas Bogendoerfer, Arnd Bergmann, Nathan Chancellor, Nick Desaulniers, Fangrui Song, Huacai Chen, Pei Huang, Jiaxun Yang, Sami Tolvanen, Ingo Molnar, Ralf Baechle, Corey Minyard, linux-mips, linux-kernel, linux-arch, stable, clang-built-linux On Thu, Jan 07, 2021 at 01:20:33PM +0000, Alexander Lobakin wrote: > Catch any symbols placed in .rel.dyn and check for these sections > to be zero-sized at link time. > Eliminates following ld warning: > > mips-alpine-linux-musl-ld: warning: orphan section `.rel.dyn' > from `init/main.o' being placed in section `.rel.dyn' > > Adopted from x86/kernel/vmlinux.lds.S. > > Suggested-by: Fangrui Song <maskray@google.com> > Signed-off-by: Alexander Lobakin <alobakin@pm.me> Reviewed-by: Kees Cook <keescook@chromium.org> -- Kees Cook ^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH v4 mips-next 4/7] MIPS: vmlinux.lds.S: catch bad .rel.dyn at link time 2021-01-07 13:20 ` [PATCH v4 mips-next 4/7] MIPS: vmlinux.lds.S: catch bad .rel.dyn at link time Alexander Lobakin ` (3 preceding siblings ...) 2021-01-07 21:48 ` [PATCH v4 mips-next 4/7] MIPS: vmlinux.lds.S: catch bad .rel.dyn at link time Kees Cook @ 2021-01-08 21:17 ` Nathan Chancellor 4 siblings, 0 replies; 22+ messages in thread From: Nathan Chancellor @ 2021-01-08 21:17 UTC (permalink / raw) To: Alexander Lobakin Cc: Thomas Bogendoerfer, Arnd Bergmann, Kees Cook, Nick Desaulniers, Fangrui Song, Huacai Chen, Pei Huang, Jiaxun Yang, Sami Tolvanen, Ingo Molnar, Ralf Baechle, Corey Minyard, linux-mips, linux-kernel, linux-arch, stable, clang-built-linux On Thu, Jan 07, 2021 at 01:20:33PM +0000, Alexander Lobakin wrote: > Catch any symbols placed in .rel.dyn and check for these sections > to be zero-sized at link time. > Eliminates following ld warning: > > mips-alpine-linux-musl-ld: warning: orphan section `.rel.dyn' > from `init/main.o' being placed in section `.rel.dyn' > > Adopted from x86/kernel/vmlinux.lds.S. > > Suggested-by: Fangrui Song <maskray@google.com> > Signed-off-by: Alexander Lobakin <alobakin@pm.me> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> > --- > arch/mips/kernel/vmlinux.lds.S | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/arch/mips/kernel/vmlinux.lds.S b/arch/mips/kernel/vmlinux.lds.S > index 0f4e46ea4458..0f736d60d43e 100644 > --- a/arch/mips/kernel/vmlinux.lds.S > +++ b/arch/mips/kernel/vmlinux.lds.S > @@ -226,4 +226,15 @@ SECTIONS > *(.pdr) > *(.reginfo) > } > + > + /* > + * Sections that should stay zero sized, which is safer to > + * explicitly check instead of blindly discarding. > + */ > + > + .rel.dyn : { > + *(.rel.*) > + *(.rel_*) > + } > + ASSERT(SIZEOF(.rel.dyn) == 0, "Unexpected run-time relocations (.rel) detected!") > } > -- > 2.30.0 > > ^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH v4 mips-next 0/7] MIPS: vmlinux.lds.S sections fixes & cleanup 2021-01-07 12:33 [PATCH v4 mips-next 0/7] MIPS: vmlinux.lds.S sections fixes & cleanup Alexander Lobakin 2021-01-07 12:34 ` [PATCH v4 mips-next 1/7] MIPS: vmlinux.lds.S: add missing PAGE_ALIGNED_DATA() section Alexander Lobakin 2021-01-07 13:20 ` [PATCH v4 mips-next 4/7] MIPS: vmlinux.lds.S: catch bad .rel.dyn at link time Alexander Lobakin @ 2021-01-07 21:51 ` Kees Cook 2021-01-09 11:12 ` Thomas Bogendoerfer 3 siblings, 0 replies; 22+ messages in thread From: Kees Cook @ 2021-01-07 21:51 UTC (permalink / raw) To: Alexander Lobakin Cc: Thomas Bogendoerfer, Arnd Bergmann, Nathan Chancellor, Nick Desaulniers, Fangrui Song, Huacai Chen, Pei Huang, Jiaxun Yang, Sami Tolvanen, Ingo Molnar, Ralf Baechle, Corey Minyard, linux-mips, linux-kernel, linux-arch, stable, clang-built-linux On Thu, Jan 07, 2021 at 12:33:38PM +0000, 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 ^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH v4 mips-next 0/7] MIPS: vmlinux.lds.S sections fixes & cleanup 2021-01-07 12:33 [PATCH v4 mips-next 0/7] MIPS: vmlinux.lds.S sections fixes & cleanup Alexander Lobakin ` (2 preceding siblings ...) 2021-01-07 21:51 ` [PATCH v4 mips-next 0/7] MIPS: vmlinux.lds.S sections fixes & cleanup Kees Cook @ 2021-01-09 11:12 ` Thomas Bogendoerfer 2021-01-09 17:22 ` Alexander Lobakin 3 siblings, 1 reply; 22+ messages in thread From: Thomas Bogendoerfer @ 2021-01-09 11:12 UTC (permalink / raw) To: Alexander Lobakin Cc: Arnd Bergmann, Kees Cook, Nathan Chancellor, Nick Desaulniers, Fangrui Song, Huacai Chen, Pei Huang, Jiaxun Yang, Sami Tolvanen, Ingo Molnar, Ralf Baechle, Corey Minyard, linux-mips, linux-kernel, linux-arch, stable, clang-built-linux On Thu, Jan 07, 2021 at 12:33:38PM +0000, 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-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 > > 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 ] ^ permalink raw reply [flat|nested] 22+ messages in thread
* Re: [PATCH v4 mips-next 0/7] MIPS: vmlinux.lds.S sections fixes & cleanup 2021-01-09 11:12 ` Thomas Bogendoerfer @ 2021-01-09 17:22 ` Alexander Lobakin 0 siblings, 0 replies; 22+ messages in thread From: Alexander Lobakin @ 2021-01-09 17:22 UTC (permalink / raw) To: Thomas Bogendoerfer Cc: Alexander Lobakin, Arnd Bergmann, Kees Cook, Nathan Chancellor, Nick Desaulniers, Fangrui Song, Huacai Chen, Pei Huang, Jiaxun Yang, Sami Tolvanen, Ingo Molnar, Ralf Baechle, Corey Minyard, linux-mips, linux-kernel, linux-arch, stable, clang-built-linux From: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Date: Sat, 9 Jan 2021 12:12:59 +0100 > On Thu, Jan 07, 2021 at 12:33:38PM +0000, 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-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 >> >> 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 ] ^ permalink raw reply [flat|nested] 22+ messages in thread
end of thread, other threads:[~2021-01-09 17:23 UTC | newest] Thread overview: 22+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2021-01-07 12:33 [PATCH v4 mips-next 0/7] MIPS: vmlinux.lds.S sections fixes & cleanup Alexander Lobakin 2021-01-07 12:34 ` [PATCH v4 mips-next 1/7] MIPS: vmlinux.lds.S: add missing PAGE_ALIGNED_DATA() section Alexander Lobakin 2021-01-07 12:34 ` [PATCH v4 mips-next 2/7] MIPS: vmlinux.lds.S: add ".gnu.attributes" to DISCARDS Alexander Lobakin 2021-01-08 21:12 ` Nathan Chancellor 2021-01-07 12:35 ` [PATCH v4 mips-next 3/7] MIPS: properly stop .eh_frame generation Alexander Lobakin 2021-01-07 21:48 ` Kees Cook 2021-01-08 21:16 ` Nathan Chancellor 2021-01-08 21:10 ` [PATCH v4 mips-next 1/7] MIPS: vmlinux.lds.S: add missing PAGE_ALIGNED_DATA() section Nathan Chancellor 2021-01-07 13:20 ` [PATCH v4 mips-next 4/7] MIPS: vmlinux.lds.S: catch bad .rel.dyn at link time Alexander Lobakin 2021-01-07 13:20 ` [PATCH v4 mips-next 5/7] MIPS: vmlinux.lds.S: explicitly declare .got table Alexander Lobakin 2021-01-07 21:49 ` Kees Cook 2021-01-08 21:17 ` Nathan Chancellor 2021-01-07 13:20 ` [PATCH v4 mips-next 6/7] vmlinux.lds.h: catch compound literals into data and BSS Alexander Lobakin 2021-01-07 21:51 ` Kees Cook 2021-01-08 21:19 ` Nathan Chancellor 2021-01-07 13:21 ` [PATCH v4 mips-next 7/7] MIPS: select ARCH_WANT_LD_ORPHAN_WARN Alexander Lobakin 2021-01-08 21:19 ` Nathan Chancellor 2021-01-07 21:48 ` [PATCH v4 mips-next 4/7] MIPS: vmlinux.lds.S: catch bad .rel.dyn at link time Kees Cook 2021-01-08 21:17 ` Nathan Chancellor 2021-01-07 21:51 ` [PATCH v4 mips-next 0/7] MIPS: vmlinux.lds.S sections fixes & cleanup Kees Cook 2021-01-09 11:12 ` Thomas Bogendoerfer 2021-01-09 17:22 ` Alexander Lobakin
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