ARM: 9444/1: add KEEP() keyword to ARM_VECTORS

Without this, the vectors are removed if LD_DEAD_CODE_DATA_ELIMINATION
is enabled. At startup, the CPU (silently) hangs in the undefined
instruction e

ARM: 9444/1: add KEEP() keyword to ARM_VECTORS

Without this, the vectors are removed if LD_DEAD_CODE_DATA_ELIMINATION
is enabled. At startup, the CPU (silently) hangs in the undefined
instruction exception as soon as the first timer interrupt arrives.

On my setup, the system also boots fine without the 2nd and 3rd KEEP()
statements, so I cannot tell whether these are actually required.

[nathan: Use OVERLAY_KEEP() to avoid breaking old ld.lld versions]

Cc: [email protected]
Fixes: ed0f94102251 ("ARM: 9404/1: arm32: enable HAVE_LD_DEAD_CODE_DATA_ELIMINATION")
Signed-off-by: Christian Eggers <[email protected]>
Reviewed-by: Linus Walleij <[email protected]>
Signed-off-by: Nathan Chancellor <[email protected]>
Signed-off-by: Russell King (Oracle) <[email protected]>

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ARM: 9443/1: Require linker to support KEEP within OVERLAY for DCE

ld.lld prior to 21.0.0 does not support using the KEEP keyword within an
overlay description, which may be needed to avoid discardi

ARM: 9443/1: Require linker to support KEEP within OVERLAY for DCE

ld.lld prior to 21.0.0 does not support using the KEEP keyword within an
overlay description, which may be needed to avoid discarding necessary
sections within an overlay with '--gc-sections', which can be enabled
for the kernel via CONFIG_LD_DEAD_CODE_DATA_ELIMINATION.

Disallow CONFIG_LD_DEAD_CODE_DATA_ELIMINATION without support for KEEP
within OVERLAY and introduce a macro, OVERLAY_KEEP, that can be used to
conditionally add KEEP when it is properly supported to avoid breaking
old versions of ld.lld.

Cc: [email protected]
Link: https://github.com/llvm/llvm-project/commit/381599f1fe973afad3094e55ec99b1620dba7d8c
Reviewed-by: Linus Walleij <[email protected]>
Signed-off-by: Nathan Chancellor <[email protected]>
Signed-off-by: Russell King (Oracle) <[email protected]>

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ARM: 9439/1: arm32: simplify ARM_MMU_KEEP usage

All current users need to add a KEEP() around the argument so the value is
actually kept, which doesn't feel very natural and is prone to upcoming bug

ARM: 9439/1: arm32: simplify ARM_MMU_KEEP usage

All current users need to add a KEEP() around the argument so the value is
actually kept, which doesn't feel very natural and is prone to upcoming bugs as
the name suggests that this macro alone already keeps things. Move that directly
into the definition.

Signed-off-by: Rolf Eike Beer <[email protected]>
Reviewed-by: Linus Walleij <[email protected]>
Signed-off-by: Russell King (Oracle) <[email protected]>

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ARM: 9404/1: arm32: enable HAVE_LD_DEAD_CODE_DATA_ELIMINATION

The current arm32 architecture does not yet support the
HAVE_LD_DEAD_CODE_DATA_ELIMINATION feature. arm32 is widely used in
embedded sce

ARM: 9404/1: arm32: enable HAVE_LD_DEAD_CODE_DATA_ELIMINATION

The current arm32 architecture does not yet support the
HAVE_LD_DEAD_CODE_DATA_ELIMINATION feature. arm32 is widely used in
embedded scenarios, and enabling this feature would be beneficial for
reducing the size of the kernel image.

In order to make this work, we keep the necessary tables by annotating
them with KEEP, also it requires further changes to linker script to KEEP
some tables and wildcard compiler generated sections into the right place.
When using ld.lld for linking, KEEP is not recognized within the OVERLAY
command, and Ard proposed a concise method to solve this problem.

It boots normally with defconfig, vexpress_defconfig and tinyconfig.

The size comparison of zImage is as follows:
defconfig vexpress_defconfig tinyconfig
5137712 5138024 424192 no dce
5032560 4997824 298384 dce
2.0% 2.7% 29.7% shrink

When using smaller config file, there is a significant reduction in the
size of the zImage.

We also tested this patch on a commercially available single-board
computer, and the comparison is as follows:
a15eb_config
2161384 no dce
2092240 dce
3.2% shrink

The zImage size has been reduced by approximately 3.2%, which is 70KB on
2.1M.

Signed-off-by: Yuntao Liu <[email protected]>
Tested-by: Arnd Bergmann <[email protected]>
Reviewed-by: Arnd Bergmann <[email protected]>
Reviewed-by: Linus Walleij <[email protected]>
Signed-off-by: Russell King (Oracle) <[email protected]>

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objtool/idle: Validate __cpuidle code as noinstr

Idle code is very like entry code in that RCU isn't available. As
such, add a little validation.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infra

objtool/idle: Validate __cpuidle code as noinstr

Idle code is very like entry code in that RCU isn't available. As
such, add a little validation.

Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Tested-by: Tony Lindgren <[email protected]>
Tested-by: Ulf Hansson <[email protected]>
Acked-by: Geert Uytterhoeven <[email protected]>
Acked-by: Rafael J. Wysocki <[email protected]>
Acked-by: Frederic Weisbecker <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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ARM: Do not use NOCROSSREFS directive with ld.lld

ld.lld does not support the NOCROSSREFS directive at the moment, which
breaks the build after commit b9baf5c8c5c3 ("ARM: Spectre-BHB
workaround"):

ARM: Do not use NOCROSSREFS directive with ld.lld

ld.lld does not support the NOCROSSREFS directive at the moment, which
breaks the build after commit b9baf5c8c5c3 ("ARM: Spectre-BHB
workaround"):

ld.lld: error: ./arch/arm/kernel/vmlinux.lds:34: AT expected, but got NOCROSSREFS

Support for this directive will eventually be implemented, at which
point a version check can be added. To avoid breaking the build in the
meantime, just define NOCROSSREFS to nothing when using ld.lld, with a
link to the issue for tracking.

Cc: [email protected]
Fixes: b9baf5c8c5c3 ("ARM: Spectre-BHB workaround")
Link: https://github.com/ClangBuiltLinux/linux/issues/1609
Signed-off-by: Nathan Chancellor <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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ARM: Spectre-BHB workaround

Workaround the Spectre BHB issues for Cortex-A15, Cortex-A57,
Cortex-A72, Cortex-A73 and Cortex-A75. We also include Brahma B15 as
well to be safe, which is affected by S

ARM: Spectre-BHB workaround

Workaround the Spectre BHB issues for Cortex-A15, Cortex-A57,
Cortex-A72, Cortex-A73 and Cortex-A75. We also include Brahma B15 as
well to be safe, which is affected by Spectre V2 in the same ways as
Cortex-A15.

Reviewed-by: Catalin Marinas <[email protected]>
Signed-off-by: Russell King (Oracle) <[email protected]>

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ARM: use LOADADDR() to get load address of sections

Use the linker's LOADADDR() macro to get the load address of the
sections, and provide a macro to set the start and end symbols.

Acked-by: Catali

ARM: use LOADADDR() to get load address of sections

Use the linker's LOADADDR() macro to get the load address of the
sections, and provide a macro to set the start and end symbols.

Acked-by: Catalin Marinas <[email protected]>
Signed-off-by: Russell King (Oracle) <[email protected]>

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arm/build: Assert for unwanted sections

In preparation for warning on orphan sections, enforce
expected-to-be-zero-sized sections (since discarding them might hide
problems with them suddenly gainin

arm/build: Assert for unwanted sections

In preparation for warning on orphan sections, enforce
expected-to-be-zero-sized sections (since discarding them might hide
problems with them suddenly gaining unexpected entries).

Signed-off-by: Kees Cook <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Cc: Russell King <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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arm/build: Add missing sections

Add missing text stub sections .vfp11_veneer and .v4_bx, as well as
missing DWARF sections, when present in the build.

Signed-off-by: Kees Cook <[email protected]

arm/build: Add missing sections

Add missing text stub sections .vfp11_veneer and .v4_bx, as well as
missing DWARF sections, when present in the build.

Signed-off-by: Kees Cook <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Reviewed-by: Nick Desaulniers <[email protected]>
Cc: Russell King <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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arm/build: Explicitly keep .ARM.attributes sections

In preparation for adding --orphan-handling=warn, explicitly keep the
.ARM.attributes section (at address 0[1]) by expanding the existing
ELF_DETA

arm/build: Explicitly keep .ARM.attributes sections

In preparation for adding --orphan-handling=warn, explicitly keep the
.ARM.attributes section (at address 0[1]) by expanding the existing
ELF_DETAILS macro into ARM_DETAILS.

[1] https://reviews.llvm.org/D85867

Suggested-by: Nick Desaulniers <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Reviewed-by: Fangrui Song <[email protected]>
Cc: Russell King <[email protected]>
Link: https://lore.kernel.org/lkml/CAKwvOdk-racgq5pxsoGS6Vtifbtrk5fmkmnoLxrQMaOvV0nPWw@mail.gmail.com/
Link: https://lore.kernel.org/r/[email protected]

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arm/build: Refactor linker script headers

In preparation for adding --orphan-handling=warn, refactor the linker
script header includes, and extract common macros.

Signed-off-by: Kees Cook <keescook

arm/build: Refactor linker script headers

In preparation for adding --orphan-handling=warn, refactor the linker
script header includes, and extract common macros.

Signed-off-by: Kees Cook <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>
Cc: Russell King <[email protected]>
Link: https://lore.kernel.org/r/[email protected]

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