* [PATCH 4.14 084/193] ACPI: Dont build ACPICA with -Os
[not found] <20230310133710.926811681@linuxfoundation.org>
@ 2023-03-10 13:37 ` Greg Kroah-Hartman
0 siblings, 0 replies; only message in thread
From: Greg Kroah-Hartman @ 2023-03-10 13:37 UTC (permalink / raw)
To: stable
Cc: Greg Kroah-Hartman, patches, Mark Rutland, Rafael J. Wysocki,
Florent Revest, Len Brown, Masami Hiramatsu, Peter Zijlstra,
Robert Moore, Steven Rostedt, Will Deacon, linux-acpi,
Catalin Marinas, Sasha Levin
From: Mark Rutland <mark.rutland@arm.com>
[ Upstream commit 8f9e0a52810dd83406c768972d022c37e7a18f1f ]
The ACPICA code has been built with '-Os' since the beginning of git
history, though there's no explanatory comment as to why.
This is unfortunate as GCC drops the alignment specificed by
'-falign-functions=N' when '-Os' is used, as reported in GCC bug 88345:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88345
This prevents CONFIG_FUNCTION_ALIGNMENT and
CONFIG_DEBUG_FORCE_FUNCTION_ALIGN_64B from having their expected effect
on the ACPICA code. This is doubly unfortunate as in subsequent patches
arm64 will depend upon CONFIG_FUNCTION_ALIGNMENT for its ftrace
implementation.
Drop the '-Os' flag when building the ACPICA code. With this removed,
the code builds cleanly and works correctly in testing so far.
I've tested this by selecting CONFIG_DEBUG_FORCE_FUNCTION_ALIGN_64B=y,
building and booting a kernel using ACPI, and looking for misaligned
text symbols:
* arm64:
Before, v6.2-rc3:
# uname -rm
6.2.0-rc3 aarch64
# grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | wc -l
5009
Before, v6.2-rc3 + fixed __cold:
# uname -rm
6.2.0-rc3-00001-g2a2bedf8bfa9 aarch64
# grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | wc -l
919
After:
# uname -rm
6.2.0-rc3-00002-g267bddc38572 aarch64
# grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | wc -l
323
# grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | grep acpi | wc -l
0
* x86_64:
Before, v6.2-rc3:
# uname -rm
6.2.0-rc3 x86_64
# grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | wc -l
11537
Before, v6.2-rc3 + fixed __cold:
# uname -rm
6.2.0-rc3-00001-g2a2bedf8bfa9 x86_64
# grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | wc -l
2805
After:
# uname -rm
6.2.0-rc3-00002-g267bddc38572 x86_64
# grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | wc -l
1357
# grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | grep acpi | wc -l
0
With the patch applied, the remaining unaligned text labels are a
combination of static call trampolines and labels in assembly, which can
be dealt with in subsequent patches.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Florent Revest <revest@chromium.org>
Cc: Len Brown <lenb@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Robert Moore <robert.moore@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Deacon <will@kernel.org>
Cc: linux-acpi@vger.kernel.org
Link: https://lore.kernel.org/r/20230123134603.1064407-4-mark.rutland@arm.com
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/acpi/acpica/Makefile | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/acpi/acpica/Makefile b/drivers/acpi/acpica/Makefile
index e05232da05888..1e8e4e7a29cb3 100644
--- a/drivers/acpi/acpica/Makefile
+++ b/drivers/acpi/acpica/Makefile
@@ -3,7 +3,7 @@
# Makefile for ACPICA Core interpreter
#
-ccflags-y := -Os -D_LINUX -DBUILDING_ACPICA
+ccflags-y := -D_LINUX -DBUILDING_ACPICA
ccflags-$(CONFIG_ACPI_DEBUG) += -DACPI_DEBUG_OUTPUT
# use acpi.o to put all files here into acpi.o modparam namespace
--
2.39.2
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2023-03-10 13:37 ` [PATCH 4.14 084/193] ACPI: Dont build ACPICA with -Os Greg Kroah-Hartman
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