[ 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>
fe00ab1eb3