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: stable@vger.kernel.org
Fixes: ed0f941022 ("ARM: 9404/1: arm32: enable HAVE_LD_DEAD_CODE_DATA_ELIMINATION")
Signed-off-by: Christian Eggers <ceggers@arri.de>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
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: stable@vger.kernel.org
Link: 381599f1fe
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
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 <eb@emlix.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
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 <liuyuntao12@huawei.com>
Tested-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
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@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20230112195540.373461409@infradead.org
ld.lld does not support the NOCROSSREFS directive at the moment, which
breaks the build after commit b9baf5c8c5 ("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: stable@vger.kernel.org
Fixes: b9baf5c8c5 ("ARM: Spectre-BHB workaround")
Link: https://github.com/ClangBuiltLinux/linux/issues/1609
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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 <catalin.marinas@arm.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
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 <catalin.marinas@arm.com>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
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 <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Russell King <linux@armlinux.org.uk>
Link: https://lore.kernel.org/r/20200821194310.3089815-19-keescook@chromium.org
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 <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Cc: Russell King <linux@armlinux.org.uk>
Link: https://lore.kernel.org/r/20200821194310.3089815-18-keescook@chromium.org
In preparation for adding --orphan-handling=warn, refactor the linker
script header includes, and extract common macros.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Russell King <linux@armlinux.org.uk>
Link: https://lore.kernel.org/r/20200821194310.3089815-16-keescook@chromium.org
2020-09-01 10:03:17 +02:00
Renamed from arch/arm/kernel/vmlinux.lds.h (Browse further)
