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 building with '-Os' overrides -falign-functions,
which prevents CONFIG_FUNCITON_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:
# grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | wc -l
908
# grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | grep acpi | wc -l
576
After:
# grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | wc -l
322
# grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | grep acpi | wc -l
0
* x86_64:
Before:
# grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | wc -l
2057
# grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | grep acpi | wc -l
706
After:
# grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | wc -l
1351
# 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
will be dealt with in subsequent patches.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.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: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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
---
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 9e0d95d76fff7..30f3fc13c29d1 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
--
2.30.2On Mon, Jan 9, 2023 at 2:58 PM Mark Rutland <mark.rutland@arm.com> wrote: > > 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 building with '-Os' overrides -falign-functions, > which prevents CONFIG_FUNCITON_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. Fair enough. Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> and please feel free to route this through the arch tree along with the rest of the series. Thanks! > 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: > # grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | wc -l > 908 > # grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | grep acpi | wc -l > 576 > > After: > # grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | wc -l > 322 > # grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | grep acpi | wc -l > 0 > > * x86_64: > > Before: > # grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | wc -l > 2057 > # grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | grep acpi | wc -l > 706 > > After: > # grep ' [Tt] ' /proc/kallsyms | grep -iv '[048c]0 [Tt] ' | wc -l > 1351 > # 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 > will be dealt with in subsequent patches. > > Signed-off-by: Mark Rutland <mark.rutland@arm.com> > Cc: Catalin Marinas <catalin.marinas@arm.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: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > 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 > --- > 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 9e0d95d76fff7..30f3fc13c29d1 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 > -- > 2.30.2 >
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