* [PATCH v7 0/5] Warn on orphan section placement
@ 2020-09-02 2:53 Kees Cook
2020-09-02 2:53 ` [PATCH v7 1/5] arm64/build: " Kees Cook
` (5 more replies)
0 siblings, 6 replies; 12+ messages in thread
From: Kees Cook @ 2020-09-02 2:53 UTC (permalink / raw)
To: Ingo Molnar
Cc: Mark Rutland, linux-arch, linux-efi, Kees Cook, Arnd Bergmann,
Catalin Marinas, Masahiro Yamada, x86, Nick Desaulniers,
Russell King, linux-kernel, clang-built-linux, Arvind Sankar,
Ingo Molnar, James Morse, Nathan Chancellor, Borislav Petkov,
Peter Collingbourne, Ard Biesheuvel, linux-arm-kernel
Hi Ingo,
The ever-shortening series. ;) Here is "v7", which is just the remaining
Makefile changes to enable orphan section warnings, now updated to
include ld-option calls.
Thanks for getting this all into -tip!
-Kees
v6: https://lore.kernel.org/lkml/20200821194310.3089815-1-keescook@chromium.org/
v5: https://lore.kernel.org/lkml/20200731230820.1742553-1-keescook@chromium.org/
v4: https://lore.kernel.org/lkml/20200629061840.4065483-1-keescook@chromium.org/
v3: https://lore.kernel.org/lkml/20200624014940.1204448-1-keescook@chromium.org/
v2: https://lore.kernel.org/lkml/20200622205815.2988115-1-keescook@chromium.org/
v1: https://lore.kernel.org/lkml/20200228002244.15240-1-keescook@chromium.org/
Kees Cook (5):
arm64/build: Warn on orphan section placement
arm/build: Warn on orphan section placement
arm/boot: Warn on orphan section placement
x86/build: Warn on orphan section placement
x86/boot/compressed: Warn on orphan section placement
arch/arm/Makefile | 4 ++++
arch/arm/boot/compressed/Makefile | 2 ++
arch/arm64/Makefile | 4 ++++
arch/x86/Makefile | 4 ++++
arch/x86/boot/compressed/Makefile | 1 +
5 files changed, 15 insertions(+)
--
2.25.1
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 12+ messages in thread
* [PATCH v7 1/5] arm64/build: Warn on orphan section placement
2020-09-02 2:53 [PATCH v7 0/5] Warn on orphan section placement Kees Cook
@ 2020-09-02 2:53 ` Kees Cook
2020-09-02 2:53 ` [PATCH v7 2/5] arm/build: " Kees Cook
` (4 subsequent siblings)
5 siblings, 0 replies; 12+ messages in thread
From: Kees Cook @ 2020-09-02 2:53 UTC (permalink / raw)
To: Ingo Molnar
Cc: Mark Rutland, linux-arch, linux-efi, Kees Cook, Arnd Bergmann,
Peter Collingbourne, Catalin Marinas, Masahiro Yamada, x86,
Nick Desaulniers, Russell King, linux-kernel, clang-built-linux,
Arvind Sankar, Ingo Molnar, James Morse, Nathan Chancellor,
Borislav Petkov, Will Deacon, Ard Biesheuvel, linux-arm-kernel
We don't want to depend on the linker's orphan section placement
heuristics as these can vary between linkers, and may change between
versions. All sections need to be explicitly handled in the linker
script.
With all sections now handled, enable orphan section warnings.
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
arch/arm64/Makefile | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/arm64/Makefile b/arch/arm64/Makefile
index 6de7f551b821..081144fcc3da 100644
--- a/arch/arm64/Makefile
+++ b/arch/arm64/Makefile
@@ -29,6 +29,10 @@ LDFLAGS_vmlinux += --fix-cortex-a53-843419
endif
endif
+# We never want expected sections to be placed heuristically by the
+# linker. All sections should be explicitly named in the linker script.
+LDFLAGS_vmlinux += $(call ld-option, --orphan-handling=warn)
+
ifeq ($(CONFIG_ARM64_USE_LSE_ATOMICS), y)
ifneq ($(CONFIG_ARM64_LSE_ATOMICS), y)
$(warning LSE atomics not supported by binutils)
--
2.25.1
_______________________________________________
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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply related [flat|nested] 12+ messages in thread
* [PATCH v7 2/5] arm/build: Warn on orphan section placement
2020-09-02 2:53 [PATCH v7 0/5] Warn on orphan section placement Kees Cook
2020-09-02 2:53 ` [PATCH v7 1/5] arm64/build: " Kees Cook
@ 2020-09-02 2:53 ` Kees Cook
2020-09-02 2:53 ` [PATCH v7 3/5] arm/boot: " Kees Cook
` (3 subsequent siblings)
5 siblings, 0 replies; 12+ messages in thread
From: Kees Cook @ 2020-09-02 2:53 UTC (permalink / raw)
To: Ingo Molnar
Cc: Mark Rutland, linux-arch, linux-efi, Kees Cook, Arnd Bergmann,
Catalin Marinas, Masahiro Yamada, x86, Nick Desaulniers,
Russell King, linux-kernel, clang-built-linux, Arvind Sankar,
Ingo Molnar, James Morse, Nathan Chancellor, Borislav Petkov,
Peter Collingbourne, Ard Biesheuvel, linux-arm-kernel
We don't want to depend on the linker's orphan section placement
heuristics as these can vary between linkers, and may change between
versions. All sections need to be explicitly handled in the linker
script.
Specifically, this would have made a recently fixed bug very obvious:
ld: warning: orphan section `.fixup' from `arch/arm/lib/copy_from_user.o' being placed in section `.fixup'
With all sections handled, enable orphan section warning.
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
arch/arm/Makefile | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/arm/Makefile b/arch/arm/Makefile
index 4e877354515f..e589da3c8949 100644
--- a/arch/arm/Makefile
+++ b/arch/arm/Makefile
@@ -16,6 +16,10 @@ LDFLAGS_vmlinux += --be8
KBUILD_LDFLAGS_MODULE += --be8
endif
+# We never want expected sections to be placed heuristically by the
+# linker. All sections should be explicitly named in the linker script.
+LDFLAGS_vmlinux += $(call ld-option, --orphan-handling=warn)
+
ifeq ($(CONFIG_ARM_MODULE_PLTS),y)
KBUILD_LDS_MODULE += $(srctree)/arch/arm/kernel/module.lds
endif
--
2.25.1
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply related [flat|nested] 12+ messages in thread
* [PATCH v7 3/5] arm/boot: Warn on orphan section placement
2020-09-02 2:53 [PATCH v7 0/5] Warn on orphan section placement Kees Cook
2020-09-02 2:53 ` [PATCH v7 1/5] arm64/build: " Kees Cook
2020-09-02 2:53 ` [PATCH v7 2/5] arm/build: " Kees Cook
@ 2020-09-02 2:53 ` Kees Cook
2020-09-02 2:53 ` [PATCH v7 4/5] x86/build: " Kees Cook
` (2 subsequent siblings)
5 siblings, 0 replies; 12+ messages in thread
From: Kees Cook @ 2020-09-02 2:53 UTC (permalink / raw)
To: Ingo Molnar
Cc: Mark Rutland, linux-arch, linux-efi, Kees Cook, Arnd Bergmann,
Catalin Marinas, Masahiro Yamada, x86, Nick Desaulniers,
Russell King, linux-kernel, clang-built-linux, Arvind Sankar,
Ingo Molnar, James Morse, Nathan Chancellor, Borislav Petkov,
Peter Collingbourne, Ard Biesheuvel, linux-arm-kernel
We don't want to depend on the linker's orphan section placement
heuristics as these can vary between linkers, and may change between
versions. All sections need to be explicitly handled in the linker script.
With all sections now handled, enable orphan section warning.
Signed-off-by: Kees Cook <keescook@chromium.org>
---
arch/arm/boot/compressed/Makefile | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/arm/boot/compressed/Makefile b/arch/arm/boot/compressed/Makefile
index b1147b7f2c8d..58028abd05d9 100644
--- a/arch/arm/boot/compressed/Makefile
+++ b/arch/arm/boot/compressed/Makefile
@@ -123,6 +123,8 @@ endif
LDFLAGS_vmlinux += --no-undefined
# Delete all temporary local symbols
LDFLAGS_vmlinux += -X
+# Report orphan sections
+LDFLAGS_vmlinux += $(call ld-option, --orphan-handling=warn)
# Next argument is a linker script
LDFLAGS_vmlinux += -T
--
2.25.1
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply related [flat|nested] 12+ messages in thread
* [PATCH v7 4/5] x86/build: Warn on orphan section placement
2020-09-02 2:53 [PATCH v7 0/5] Warn on orphan section placement Kees Cook
` (2 preceding siblings ...)
2020-09-02 2:53 ` [PATCH v7 3/5] arm/boot: " Kees Cook
@ 2020-09-02 2:53 ` Kees Cook
2020-09-05 22:48 ` Arvind Sankar
2020-09-02 2:53 ` [PATCH v7 5/5] x86/boot/compressed: " Kees Cook
2020-09-02 19:04 ` [PATCH v7 0/5] " Nick Desaulniers
5 siblings, 1 reply; 12+ messages in thread
From: Kees Cook @ 2020-09-02 2:53 UTC (permalink / raw)
To: Ingo Molnar
Cc: Mark Rutland, linux-arch, linux-efi, Kees Cook, Arnd Bergmann,
Catalin Marinas, Masahiro Yamada, x86, Nick Desaulniers,
Russell King, linux-kernel, clang-built-linux, Arvind Sankar,
Ingo Molnar, James Morse, Nathan Chancellor, Borislav Petkov,
Peter Collingbourne, Ard Biesheuvel, linux-arm-kernel
We don't want to depend on the linker's orphan section placement
heuristics as these can vary between linkers, and may change between
versions. All sections need to be explicitly handled in the linker script.
Now that all sections are explicitly handled, enable orphan section
warnings.
Signed-off-by: Kees Cook <keescook@chromium.org>
---
arch/x86/Makefile | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/x86/Makefile b/arch/x86/Makefile
index 4346ffb2e39f..154259f18b8b 100644
--- a/arch/x86/Makefile
+++ b/arch/x86/Makefile
@@ -209,6 +209,10 @@ ifdef CONFIG_X86_64
LDFLAGS_vmlinux += -z max-page-size=0x200000
endif
+# We never want expected sections to be placed heuristically by the
+# linker. All sections should be explicitly named in the linker script.
+LDFLAGS_vmlinux += $(call ld-option, --orphan-handling=warn)
+
archscripts: scripts_basic
$(Q)$(MAKE) $(build)=arch/x86/tools relocs
--
2.25.1
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply related [flat|nested] 12+ messages in thread
* [PATCH v7 5/5] x86/boot/compressed: Warn on orphan section placement
2020-09-02 2:53 [PATCH v7 0/5] Warn on orphan section placement Kees Cook
` (3 preceding siblings ...)
2020-09-02 2:53 ` [PATCH v7 4/5] x86/build: " Kees Cook
@ 2020-09-02 2:53 ` Kees Cook
2020-09-02 19:04 ` [PATCH v7 0/5] " Nick Desaulniers
5 siblings, 0 replies; 12+ messages in thread
From: Kees Cook @ 2020-09-02 2:53 UTC (permalink / raw)
To: Ingo Molnar
Cc: Mark Rutland, linux-arch, linux-efi, Kees Cook, Arnd Bergmann,
Catalin Marinas, Masahiro Yamada, x86, Nick Desaulniers,
Russell King, linux-kernel, clang-built-linux, Arvind Sankar,
Ingo Molnar, James Morse, Nathan Chancellor, Borislav Petkov,
Peter Collingbourne, Ard Biesheuvel, linux-arm-kernel
We don't want to depend on the linker's orphan section placement
heuristics as these can vary between linkers, and may change between
versions. All sections need to be explicitly handled in the linker
script.
Now that all sections are explicitly handled, enable orphan section
warnings.
Signed-off-by: Kees Cook <keescook@chromium.org>
---
arch/x86/boot/compressed/Makefile | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/x86/boot/compressed/Makefile b/arch/x86/boot/compressed/Makefile
index 5b7f6e175b03..871cc071c925 100644
--- a/arch/x86/boot/compressed/Makefile
+++ b/arch/x86/boot/compressed/Makefile
@@ -54,6 +54,7 @@ KBUILD_LDFLAGS += $(call ld-option,--no-ld-generated-unwind-info)
# Compressed kernel should be built as PIE since it may be loaded at any
# address by the bootloader.
LDFLAGS_vmlinux := -pie $(call ld-option, --no-dynamic-linker)
+LDFLAGS_vmlinux += $(call ld-option, --orphan-handling=warn)
LDFLAGS_vmlinux += -T
hostprogs := mkpiggy
--
2.25.1
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply related [flat|nested] 12+ messages in thread
* Re: [PATCH v7 0/5] Warn on orphan section placement
2020-09-02 2:53 [PATCH v7 0/5] Warn on orphan section placement Kees Cook
` (4 preceding siblings ...)
2020-09-02 2:53 ` [PATCH v7 5/5] x86/boot/compressed: " Kees Cook
@ 2020-09-02 19:04 ` Nick Desaulniers
2020-09-04 5:58 ` Ingo Molnar
5 siblings, 1 reply; 12+ messages in thread
From: Nick Desaulniers @ 2020-09-02 19:04 UTC (permalink / raw)
To: Kees Cook
Cc: Mark Rutland, linux-arch, linux-efi, LKML, Arnd Bergmann,
Catalin Marinas, Masahiro Yamada,
maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT), Russell King,
Ard Biesheuvel, clang-built-linux, Arvind Sankar, Ingo Molnar,
James Morse, Nathan Chancellor, Borislav Petkov,
Peter Collingbourne, Ingo Molnar, Linux ARM
On Tue, Sep 1, 2020 at 7:53 PM Kees Cook <keescook@chromium.org> wrote:
>
> Hi Ingo,
>
> The ever-shortening series. ;) Here is "v7", which is just the remaining
> Makefile changes to enable orphan section warnings, now updated to
> include ld-option calls.
>
> Thanks for getting this all into -tip!
For the series,
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
As the recent ppc vdso boogaloo exposed, what about the vdsos?
* arch/x86/entry/vdso/Makefile
* arch/arm/vdso/Makefile
* arch/arm64/kernel/vdso/Makefile
* arch/arm64/kernel/vdso32/Makefile
>
> -Kees
>
> v6: https://lore.kernel.org/lkml/20200821194310.3089815-1-keescook@chromium.org/
> v5: https://lore.kernel.org/lkml/20200731230820.1742553-1-keescook@chromium.org/
> v4: https://lore.kernel.org/lkml/20200629061840.4065483-1-keescook@chromium.org/
> v3: https://lore.kernel.org/lkml/20200624014940.1204448-1-keescook@chromium.org/
> v2: https://lore.kernel.org/lkml/20200622205815.2988115-1-keescook@chromium.org/
> v1: https://lore.kernel.org/lkml/20200228002244.15240-1-keescook@chromium.org/
>
> Kees Cook (5):
> arm64/build: Warn on orphan section placement
> arm/build: Warn on orphan section placement
> arm/boot: Warn on orphan section placement
> x86/build: Warn on orphan section placement
> x86/boot/compressed: Warn on orphan section placement
>
> arch/arm/Makefile | 4 ++++
> arch/arm/boot/compressed/Makefile | 2 ++
> arch/arm64/Makefile | 4 ++++
> arch/x86/Makefile | 4 ++++
> arch/x86/boot/compressed/Makefile | 1 +
> 5 files changed, 15 insertions(+)
>
> --
> 2.25.1
>
--
Thanks,
~Nick Desaulniers
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v7 0/5] Warn on orphan section placement
2020-09-02 19:04 ` [PATCH v7 0/5] " Nick Desaulniers
@ 2020-09-04 5:58 ` Ingo Molnar
2020-09-04 18:20 ` Kees Cook
0 siblings, 1 reply; 12+ messages in thread
From: Ingo Molnar @ 2020-09-04 5:58 UTC (permalink / raw)
To: Nick Desaulniers, Kees Cook
Cc: Mark Rutland, linux-arch, linux-efi, Kees Cook, Arnd Bergmann,
Catalin Marinas, Masahiro Yamada,
maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT), Russell King,
LKML, clang-built-linux, Arvind Sankar, Ingo Molnar, James Morse,
Nathan Chancellor, Borislav Petkov, Peter Collingbourne,
Ard Biesheuvel, Linux ARM
* Nick Desaulniers <ndesaulniers@google.com> wrote:
> On Tue, Sep 1, 2020 at 7:53 PM Kees Cook <keescook@chromium.org> wrote:
> >
> > Hi Ingo,
> >
> > The ever-shortening series. ;) Here is "v7", which is just the remaining
> > Makefile changes to enable orphan section warnings, now updated to
> > include ld-option calls.
> >
> > Thanks for getting this all into -tip!
>
> For the series,
> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
>
> As the recent ppc vdso boogaloo exposed, what about the vdsos?
> * arch/x86/entry/vdso/Makefile
> * arch/arm/vdso/Makefile
> * arch/arm64/kernel/vdso/Makefile
> * arch/arm64/kernel/vdso32/Makefile
Kees, will these patches DTRT for the vDSO builds? I will be unable to test
these patches on that old system until tomorrow the earliest.
I'm keeping these latest changes in WIP.core/build for now.
Thanks,
Ingo
_______________________________________________
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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v7 0/5] Warn on orphan section placement
2020-09-04 5:58 ` Ingo Molnar
@ 2020-09-04 18:20 ` Kees Cook
2020-09-06 7:24 ` Ingo Molnar
0 siblings, 1 reply; 12+ messages in thread
From: Kees Cook @ 2020-09-04 18:20 UTC (permalink / raw)
To: Ingo Molnar
Cc: Mark Rutland, linux-arch, linux-efi, Arnd Bergmann,
Catalin Marinas, Masahiro Yamada,
maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT), Nick Desaulniers,
Russell King, LKML, clang-built-linux, Arvind Sankar, Ingo Molnar,
James Morse, Nathan Chancellor, Borislav Petkov,
Peter Collingbourne, Ard Biesheuvel, Linux ARM
On Fri, Sep 04, 2020 at 07:58:25AM +0200, Ingo Molnar wrote:
>
> * Nick Desaulniers <ndesaulniers@google.com> wrote:
>
> > On Tue, Sep 1, 2020 at 7:53 PM Kees Cook <keescook@chromium.org> wrote:
> > >
> > > Hi Ingo,
> > >
> > > The ever-shortening series. ;) Here is "v7", which is just the remaining
> > > Makefile changes to enable orphan section warnings, now updated to
> > > include ld-option calls.
> > >
> > > Thanks for getting this all into -tip!
> >
> > For the series,
> > Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
> >
> > As the recent ppc vdso boogaloo exposed, what about the vdsos?
> > * arch/x86/entry/vdso/Makefile
> > * arch/arm/vdso/Makefile
> > * arch/arm64/kernel/vdso/Makefile
> > * arch/arm64/kernel/vdso32/Makefile
>
> Kees, will these patches DTRT for the vDSO builds? I will be unable to test
> these patches on that old system until tomorrow the earliest.
I would like to see VDSO done next, but it's entirely separate from
this series. This series only touches the core kernel build (i.e. via the
interactions with scripts/link-vmlinux.sh) or the boot stubs. So there
is no impact on VDSO linking.
> I'm keeping these latest changes in WIP.core/build for now.
They should be safe to land in -next, which is important so we can shake
out any other sneaky sections that all our existing testing hasn't
found. :)
--
Kees Cook
_______________________________________________
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linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v7 4/5] x86/build: Warn on orphan section placement
2020-09-02 2:53 ` [PATCH v7 4/5] x86/build: " Kees Cook
@ 2020-09-05 22:48 ` Arvind Sankar
2020-09-08 20:17 ` Arvind Sankar
0 siblings, 1 reply; 12+ messages in thread
From: Arvind Sankar @ 2020-09-05 22:48 UTC (permalink / raw)
To: Kees Cook
Cc: Mark Rutland, linux-arch, linux-efi, linux-kernel, Arnd Bergmann,
Catalin Marinas, Masahiro Yamada, x86, Nick Desaulniers,
Russell King, Ard Biesheuvel, clang-built-linux, Arvind Sankar,
Ingo Molnar, James Morse, Nathan Chancellor, Borislav Petkov,
Peter Collingbourne, Ingo Molnar, linux-arm-kernel
On Tue, Sep 01, 2020 at 07:53:46PM -0700, Kees Cook wrote:
> We don't want to depend on the linker's orphan section placement
> heuristics as these can vary between linkers, and may change between
> versions. All sections need to be explicitly handled in the linker script.
>
> Now that all sections are explicitly handled, enable orphan section
> warnings.
>
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
> arch/x86/Makefile | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/arch/x86/Makefile b/arch/x86/Makefile
> index 4346ffb2e39f..154259f18b8b 100644
> --- a/arch/x86/Makefile
> +++ b/arch/x86/Makefile
> @@ -209,6 +209,10 @@ ifdef CONFIG_X86_64
> LDFLAGS_vmlinux += -z max-page-size=0x200000
> endif
>
> +# We never want expected sections to be placed heuristically by the
> +# linker. All sections should be explicitly named in the linker script.
> +LDFLAGS_vmlinux += $(call ld-option, --orphan-handling=warn)
> +
> archscripts: scripts_basic
> $(Q)$(MAKE) $(build)=arch/x86/tools relocs
>
> --
> 2.25.1
>
With LLVM=1 and GCOV_KERNEL/GCOV_PROFILE_ALL enabled, there are
.eh_frame sections created. I see that KASAN and KCSAN currently discard
them. Does GCOV actually need them or should it also discard?
Thanks.
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v7 0/5] Warn on orphan section placement
2020-09-04 18:20 ` Kees Cook
@ 2020-09-06 7:24 ` Ingo Molnar
0 siblings, 0 replies; 12+ messages in thread
From: Ingo Molnar @ 2020-09-06 7:24 UTC (permalink / raw)
To: Kees Cook
Cc: Mark Rutland, linux-arch, linux-efi, Arnd Bergmann,
Catalin Marinas, Masahiro Yamada,
maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT), Nick Desaulniers,
Russell King, LKML, clang-built-linux, Arvind Sankar, Ingo Molnar,
James Morse, Nathan Chancellor, Borislav Petkov,
Peter Collingbourne, Ard Biesheuvel, Linux ARM
* Kees Cook <keescook@chromium.org> wrote:
> On Fri, Sep 04, 2020 at 07:58:25AM +0200, Ingo Molnar wrote:
> >
> > * Nick Desaulniers <ndesaulniers@google.com> wrote:
> >
> > > On Tue, Sep 1, 2020 at 7:53 PM Kees Cook <keescook@chromium.org> wrote:
> > > >
> > > > Hi Ingo,
> > > >
> > > > The ever-shortening series. ;) Here is "v7", which is just the remaining
> > > > Makefile changes to enable orphan section warnings, now updated to
> > > > include ld-option calls.
> > > >
> > > > Thanks for getting this all into -tip!
> > >
> > > For the series,
> > > Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
> > >
> > > As the recent ppc vdso boogaloo exposed, what about the vdsos?
> > > * arch/x86/entry/vdso/Makefile
> > > * arch/arm/vdso/Makefile
> > > * arch/arm64/kernel/vdso/Makefile
> > > * arch/arm64/kernel/vdso32/Makefile
> >
> > Kees, will these patches DTRT for the vDSO builds? I will be unable to test
> > these patches on that old system until tomorrow the earliest.
>
> I would like to see VDSO done next, but it's entirely separate from
> this series. This series only touches the core kernel build (i.e. via the
> interactions with scripts/link-vmlinux.sh) or the boot stubs. So there
> is no impact on VDSO linking.
Great!
I also double checked that things still build fine with ancient LD.
> > I'm keeping these latest changes in WIP.core/build for now.
>
> They should be safe to land in -next, which is important so we can shake
> out any other sneaky sections that all our existing testing hasn't
> found. :)
OK, cool - I've graduated them over into tip:core/build. :-)
Thanks,
Ingo
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^ permalink raw reply [flat|nested] 12+ messages in thread
* Re: [PATCH v7 4/5] x86/build: Warn on orphan section placement
2020-09-05 22:48 ` Arvind Sankar
@ 2020-09-08 20:17 ` Arvind Sankar
0 siblings, 0 replies; 12+ messages in thread
From: Arvind Sankar @ 2020-09-08 20:17 UTC (permalink / raw)
To: Arvind Sankar
Cc: Mark Rutland, linux-arch, linux-efi, linux-kernel, Kees Cook,
Arnd Bergmann, Catalin Marinas, Masahiro Yamada, x86,
Nick Desaulniers, Russell King, Ingo Molnar, clang-built-linux,
Ingo Molnar, James Morse, Nathan Chancellor, Borislav Petkov,
Peter Collingbourne, Ard Biesheuvel, linux-arm-kernel
On Sat, Sep 05, 2020 at 06:48:35PM -0400, Arvind Sankar wrote:
> On Tue, Sep 01, 2020 at 07:53:46PM -0700, Kees Cook wrote:
> > We don't want to depend on the linker's orphan section placement
> > heuristics as these can vary between linkers, and may change between
> > versions. All sections need to be explicitly handled in the linker script.
> >
> > Now that all sections are explicitly handled, enable orphan section
> > warnings.
> >
> > Signed-off-by: Kees Cook <keescook@chromium.org>
> > ---
> > arch/x86/Makefile | 4 ++++
> > 1 file changed, 4 insertions(+)
> >
> > diff --git a/arch/x86/Makefile b/arch/x86/Makefile
> > index 4346ffb2e39f..154259f18b8b 100644
> > --- a/arch/x86/Makefile
> > +++ b/arch/x86/Makefile
> > @@ -209,6 +209,10 @@ ifdef CONFIG_X86_64
> > LDFLAGS_vmlinux += -z max-page-size=0x200000
> > endif
> >
> > +# We never want expected sections to be placed heuristically by the
> > +# linker. All sections should be explicitly named in the linker script.
> > +LDFLAGS_vmlinux += $(call ld-option, --orphan-handling=warn)
> > +
> > archscripts: scripts_basic
> > $(Q)$(MAKE) $(build)=arch/x86/tools relocs
> >
> > --
> > 2.25.1
> >
>
> With LLVM=1 and GCOV_KERNEL/GCOV_PROFILE_ALL enabled, there are
> .eh_frame sections created. I see that KASAN and KCSAN currently discard
> them. Does GCOV actually need them or should it also discard?
>
> Thanks.
Also, with LLD 10.0.1 which is going to be the minimum supported
version, the relocation sections etc still generate warnings.
ld.lld: warning:
arch/x86/video/built-in.a(fbdev.o):(.rela.orc_unwind_ip) is being placed
in '.rela.orc_unwind_ip'
ld.lld: warning: .tmp_vmlinux.kallsyms2.o:(.rela.rodata) is being placed
in '.rela.rodata'
ld.lld: warning: <internal>:(.bss.rel.ro) is being placed in
'.bss.rel.ro'
ld.lld: warning: <internal>:(.eh_frame) is being placed in '.eh_frame'
ld.lld: warning: <internal>:(.symtab_shndx) is being placed in
'.symtab_shndx'
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^ permalink raw reply [flat|nested] 12+ messages in thread
end of thread, other threads:[~2020-09-08 20:19 UTC | newest]
Thread overview: 12+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2020-09-02 2:53 [PATCH v7 0/5] Warn on orphan section placement Kees Cook
2020-09-02 2:53 ` [PATCH v7 1/5] arm64/build: " Kees Cook
2020-09-02 2:53 ` [PATCH v7 2/5] arm/build: " Kees Cook
2020-09-02 2:53 ` [PATCH v7 3/5] arm/boot: " Kees Cook
2020-09-02 2:53 ` [PATCH v7 4/5] x86/build: " Kees Cook
2020-09-05 22:48 ` Arvind Sankar
2020-09-08 20:17 ` Arvind Sankar
2020-09-02 2:53 ` [PATCH v7 5/5] x86/boot/compressed: " Kees Cook
2020-09-02 19:04 ` [PATCH v7 0/5] " Nick Desaulniers
2020-09-04 5:58 ` Ingo Molnar
2020-09-04 18:20 ` Kees Cook
2020-09-06 7:24 ` Ingo Molnar
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