[PATCH] uml: reuse i386 cpu-specific tuning
Make UML share the underlying cpu-specific tuning done on i386.
Actually, for now many config options aren't used a lot - but that can be done
later. Also, UML relies on GCC optimization for things like memcpy and such
more than i386, so specifying the correct -march and -mtune should be enough.
Later, we may want to correct some other stuff.
For instance, since FPU context switching, for us, is done (at least
partially, i.e. between our kernelspace and userspace) by the host, we may
allow usage of FPU operations by GCC. This doesn't hold for kernelspace vs.
kernelspace, but we don't support preemption.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-31 07:00:07 +08:00
|
|
|
# CPU tuning section - shared with UML.
|
|
|
|
|
# Must change only cflags-y (or [yn]), not CFLAGS! That makes a difference for UML.
|
|
|
|
|
|
2006-01-08 17:04:09 +08:00
|
|
|
#-mtune exists since gcc 3.4
|
[PATCH] i386: use -mcpu, not -mtune, for GCCs older than 3.4
I just noted that -mtune is used, which is only supported on recent GCCs; by
reading http://gcc.gnu.org/gcc-3.4/changes.html, you see "-mcpu has been
renamed to -mtune.", so for GCC < 3.4 we're not using any specific tuning in
the appropriate cases. However -mcpu is deprecated, so use -mtune when
possible.
This was introduced by commit e9d4dce954a60dc23dd1d967766ca2347b780e54 of the
old tree (between 2.6.10-rc3 and 2.6.10) by Linus Torvalds, to remove the use
of -march, since that could trigger gcc using SSE on its own. But no
attention was used about using -mcpu vs. -mtune.
And btw, the old 2.6.4 code (for instance) was:
cflags-$(CONFIG_MPENTIUMII) += $(call check_gcc,-march=pentium2,-march=i686)
cflags-$(CONFIG_MPENTIUMIII) += $(call check_gcc,-march=pentium3,-march=i686)
cflags-$(CONFIG_MPENTIUMM) += $(call check_gcc,-march=pentium3,-march=i686)
cflags-$(CONFIG_MPENTIUM4) += $(call check_gcc,-march=pentium4,-march=i686)
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-31 07:00:09 +08:00
|
|
|
HAS_MTUNE := $(call cc-option-yn, -mtune=i386)
|
|
|
|
|
ifeq ($(HAS_MTUNE),y)
|
2007-05-03 01:27:06 +08:00
|
|
|
tune = $(call cc-option,-mtune=$(1),$(2))
|
[PATCH] i386: use -mcpu, not -mtune, for GCCs older than 3.4
I just noted that -mtune is used, which is only supported on recent GCCs; by
reading http://gcc.gnu.org/gcc-3.4/changes.html, you see "-mcpu has been
renamed to -mtune.", so for GCC < 3.4 we're not using any specific tuning in
the appropriate cases. However -mcpu is deprecated, so use -mtune when
possible.
This was introduced by commit e9d4dce954a60dc23dd1d967766ca2347b780e54 of the
old tree (between 2.6.10-rc3 and 2.6.10) by Linus Torvalds, to remove the use
of -march, since that could trigger gcc using SSE on its own. But no
attention was used about using -mcpu vs. -mtune.
And btw, the old 2.6.4 code (for instance) was:
cflags-$(CONFIG_MPENTIUMII) += $(call check_gcc,-march=pentium2,-march=i686)
cflags-$(CONFIG_MPENTIUMIII) += $(call check_gcc,-march=pentium3,-march=i686)
cflags-$(CONFIG_MPENTIUMM) += $(call check_gcc,-march=pentium3,-march=i686)
cflags-$(CONFIG_MPENTIUM4) += $(call check_gcc,-march=pentium4,-march=i686)
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-31 07:00:09 +08:00
|
|
|
else
|
2007-05-03 01:27:06 +08:00
|
|
|
tune = $(call cc-option,-mcpu=$(1),$(2))
|
[PATCH] i386: use -mcpu, not -mtune, for GCCs older than 3.4
I just noted that -mtune is used, which is only supported on recent GCCs; by
reading http://gcc.gnu.org/gcc-3.4/changes.html, you see "-mcpu has been
renamed to -mtune.", so for GCC < 3.4 we're not using any specific tuning in
the appropriate cases. However -mcpu is deprecated, so use -mtune when
possible.
This was introduced by commit e9d4dce954a60dc23dd1d967766ca2347b780e54 of the
old tree (between 2.6.10-rc3 and 2.6.10) by Linus Torvalds, to remove the use
of -march, since that could trigger gcc using SSE on its own. But no
attention was used about using -mcpu vs. -mtune.
And btw, the old 2.6.4 code (for instance) was:
cflags-$(CONFIG_MPENTIUMII) += $(call check_gcc,-march=pentium2,-march=i686)
cflags-$(CONFIG_MPENTIUMIII) += $(call check_gcc,-march=pentium3,-march=i686)
cflags-$(CONFIG_MPENTIUMM) += $(call check_gcc,-march=pentium3,-march=i686)
cflags-$(CONFIG_MPENTIUM4) += $(call check_gcc,-march=pentium4,-march=i686)
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-31 07:00:09 +08:00
|
|
|
endif
|
|
|
|
|
|
[PATCH] uml: reuse i386 cpu-specific tuning
Make UML share the underlying cpu-specific tuning done on i386.
Actually, for now many config options aren't used a lot - but that can be done
later. Also, UML relies on GCC optimization for things like memcpy and such
more than i386, so specifying the correct -march and -mtune should be enough.
Later, we may want to correct some other stuff.
For instance, since FPU context switching, for us, is done (at least
partially, i.e. between our kernelspace and userspace) by the host, we may
allow usage of FPU operations by GCC. This doesn't hold for kernelspace vs.
kernelspace, but we don't support preemption.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-31 07:00:07 +08:00
|
|
|
align := $(cc-option-align)
|
|
|
|
|
cflags-$(CONFIG_M386) += -march=i386
|
|
|
|
|
cflags-$(CONFIG_M486) += -march=i486
|
|
|
|
|
cflags-$(CONFIG_M586) += -march=i586
|
|
|
|
|
cflags-$(CONFIG_M586TSC) += -march=i586
|
2006-01-08 17:04:09 +08:00
|
|
|
cflags-$(CONFIG_M586MMX) += -march=pentium-mmx
|
[PATCH] uml: reuse i386 cpu-specific tuning
Make UML share the underlying cpu-specific tuning done on i386.
Actually, for now many config options aren't used a lot - but that can be done
later. Also, UML relies on GCC optimization for things like memcpy and such
more than i386, so specifying the correct -march and -mtune should be enough.
Later, we may want to correct some other stuff.
For instance, since FPU context switching, for us, is done (at least
partially, i.e. between our kernelspace and userspace) by the host, we may
allow usage of FPU operations by GCC. This doesn't hold for kernelspace vs.
kernelspace, but we don't support preemption.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-31 07:00:07 +08:00
|
|
|
cflags-$(CONFIG_M686) += -march=i686
|
[PATCH] i386: use -mcpu, not -mtune, for GCCs older than 3.4
I just noted that -mtune is used, which is only supported on recent GCCs; by
reading http://gcc.gnu.org/gcc-3.4/changes.html, you see "-mcpu has been
renamed to -mtune.", so for GCC < 3.4 we're not using any specific tuning in
the appropriate cases. However -mcpu is deprecated, so use -mtune when
possible.
This was introduced by commit e9d4dce954a60dc23dd1d967766ca2347b780e54 of the
old tree (between 2.6.10-rc3 and 2.6.10) by Linus Torvalds, to remove the use
of -march, since that could trigger gcc using SSE on its own. But no
attention was used about using -mcpu vs. -mtune.
And btw, the old 2.6.4 code (for instance) was:
cflags-$(CONFIG_MPENTIUMII) += $(call check_gcc,-march=pentium2,-march=i686)
cflags-$(CONFIG_MPENTIUMIII) += $(call check_gcc,-march=pentium3,-march=i686)
cflags-$(CONFIG_MPENTIUMM) += $(call check_gcc,-march=pentium3,-march=i686)
cflags-$(CONFIG_MPENTIUM4) += $(call check_gcc,-march=pentium4,-march=i686)
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-31 07:00:09 +08:00
|
|
|
cflags-$(CONFIG_MPENTIUMII) += -march=i686 $(call tune,pentium2)
|
|
|
|
|
cflags-$(CONFIG_MPENTIUMIII) += -march=i686 $(call tune,pentium3)
|
|
|
|
|
cflags-$(CONFIG_MPENTIUMM) += -march=i686 $(call tune,pentium3)
|
|
|
|
|
cflags-$(CONFIG_MPENTIUM4) += -march=i686 $(call tune,pentium4)
|
[PATCH] uml: reuse i386 cpu-specific tuning
Make UML share the underlying cpu-specific tuning done on i386.
Actually, for now many config options aren't used a lot - but that can be done
later. Also, UML relies on GCC optimization for things like memcpy and such
more than i386, so specifying the correct -march and -mtune should be enough.
Later, we may want to correct some other stuff.
For instance, since FPU context switching, for us, is done (at least
partially, i.e. between our kernelspace and userspace) by the host, we may
allow usage of FPU operations by GCC. This doesn't hold for kernelspace vs.
kernelspace, but we don't support preemption.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-31 07:00:07 +08:00
|
|
|
cflags-$(CONFIG_MK6) += -march=k6
|
|
|
|
|
# Please note, that patches that add -march=athlon-xp and friends are pointless.
|
|
|
|
|
# They make zero difference whatsosever to performance at this time.
|
2006-01-08 17:04:09 +08:00
|
|
|
cflags-$(CONFIG_MK7) += -march=athlon
|
|
|
|
|
cflags-$(CONFIG_MK8) += $(call cc-option,-march=k8,-march=athlon)
|
[PATCH] uml: reuse i386 cpu-specific tuning
Make UML share the underlying cpu-specific tuning done on i386.
Actually, for now many config options aren't used a lot - but that can be done
later. Also, UML relies on GCC optimization for things like memcpy and such
more than i386, so specifying the correct -march and -mtune should be enough.
Later, we may want to correct some other stuff.
For instance, since FPU context switching, for us, is done (at least
partially, i.e. between our kernelspace and userspace) by the host, we may
allow usage of FPU operations by GCC. This doesn't hold for kernelspace vs.
kernelspace, but we don't support preemption.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-31 07:00:07 +08:00
|
|
|
cflags-$(CONFIG_MCRUSOE) += -march=i686 $(align)-functions=0 $(align)-jumps=0 $(align)-loops=0
|
[PATCH] i386: use -mcpu, not -mtune, for GCCs older than 3.4
I just noted that -mtune is used, which is only supported on recent GCCs; by
reading http://gcc.gnu.org/gcc-3.4/changes.html, you see "-mcpu has been
renamed to -mtune.", so for GCC < 3.4 we're not using any specific tuning in
the appropriate cases. However -mcpu is deprecated, so use -mtune when
possible.
This was introduced by commit e9d4dce954a60dc23dd1d967766ca2347b780e54 of the
old tree (between 2.6.10-rc3 and 2.6.10) by Linus Torvalds, to remove the use
of -march, since that could trigger gcc using SSE on its own. But no
attention was used about using -mcpu vs. -mtune.
And btw, the old 2.6.4 code (for instance) was:
cflags-$(CONFIG_MPENTIUMII) += $(call check_gcc,-march=pentium2,-march=i686)
cflags-$(CONFIG_MPENTIUMIII) += $(call check_gcc,-march=pentium3,-march=i686)
cflags-$(CONFIG_MPENTIUMM) += $(call check_gcc,-march=pentium3,-march=i686)
cflags-$(CONFIG_MPENTIUM4) += $(call check_gcc,-march=pentium4,-march=i686)
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-31 07:00:09 +08:00
|
|
|
cflags-$(CONFIG_MEFFICEON) += -march=i686 $(call tune,pentium3) $(align)-functions=0 $(align)-jumps=0 $(align)-loops=0
|
[PATCH] uml: reuse i386 cpu-specific tuning
Make UML share the underlying cpu-specific tuning done on i386.
Actually, for now many config options aren't used a lot - but that can be done
later. Also, UML relies on GCC optimization for things like memcpy and such
more than i386, so specifying the correct -march and -mtune should be enough.
Later, we may want to correct some other stuff.
For instance, since FPU context switching, for us, is done (at least
partially, i.e. between our kernelspace and userspace) by the host, we may
allow usage of FPU operations by GCC. This doesn't hold for kernelspace vs.
kernelspace, but we don't support preemption.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-31 07:00:07 +08:00
|
|
|
cflags-$(CONFIG_MWINCHIPC6) += $(call cc-option,-march=winchip-c6,-march=i586)
|
|
|
|
|
cflags-$(CONFIG_MWINCHIP3D) += $(call cc-option,-march=winchip2,-march=i586)
|
|
|
|
|
cflags-$(CONFIG_MCYRIXIII) += $(call cc-option,-march=c3,-march=i486) $(align)-functions=0 $(align)-jumps=0 $(align)-loops=0
|
|
|
|
|
cflags-$(CONFIG_MVIAC3_2) += $(call cc-option,-march=c3-2,-march=i686)
|
2007-05-03 01:27:05 +08:00
|
|
|
cflags-$(CONFIG_MVIAC7) += -march=i686
|
2007-05-03 01:27:06 +08:00
|
|
|
cflags-$(CONFIG_MCORE2) += -march=i686 $(call tune,core2)
|
2009-08-22 05:06:23 +08:00
|
|
|
cflags-$(CONFIG_MATOM) += $(call cc-option,-march=atom,$(call cc-option,-march=core2,-march=i686)) \
|
|
|
|
|
$(call cc-option,-mtune=atom,$(call cc-option,-mtune=generic))
|
[PATCH] uml: reuse i386 cpu-specific tuning
Make UML share the underlying cpu-specific tuning done on i386.
Actually, for now many config options aren't used a lot - but that can be done
later. Also, UML relies on GCC optimization for things like memcpy and such
more than i386, so specifying the correct -march and -mtune should be enough.
Later, we may want to correct some other stuff.
For instance, since FPU context switching, for us, is done (at least
partially, i.e. between our kernelspace and userspace) by the host, we may
allow usage of FPU operations by GCC. This doesn't hold for kernelspace vs.
kernelspace, but we don't support preemption.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-31 07:00:07 +08:00
|
|
|
|
|
|
|
|
# AMD Elan support
|
|
|
|
|
cflags-$(CONFIG_X86_ELAN) += -march=i486
|
|
|
|
|
|
|
|
|
|
# Geode GX1 support
|
2006-01-08 17:04:09 +08:00
|
|
|
cflags-$(CONFIG_MGEODEGX1) += -march=pentium-mmx
|
2009-10-01 23:11:10 +08:00
|
|
|
cflags-$(CONFIG_MGEODE_LX) += $(call cc-option,-march=geode,-march=pentium-mmx)
|
2006-03-25 23:29:06 +08:00
|
|
|
# add at the end to overwrite eventual tuning options from earlier
|
|
|
|
|
# cpu entries
|
2007-05-03 01:27:06 +08:00
|
|
|
cflags-$(CONFIG_X86_GENERIC) += $(call tune,generic,$(call tune,i686))
|
2006-03-25 23:29:06 +08:00
|
|
|
|
x86: Prevent GCC 4.4.x (pentium-mmx et al) function prologue wreckage
When the kernel is compiled with -pg for tracing GCC 4.4.x inserts
stack alignment of a function _before_ the mcount prologue if the
-march=pentium-mmx is set and -mtune=generic is not set. This breaks
the assumption of the function graph tracer which expects that the
mcount prologue
push %ebp
mov %esp, %ebp
is the first stack operation in a function because it needs to modify
the function return address on the stack to trap into the tracer
before returning to the real caller.
The generated code is:
push %edi
lea 0x8(%esp),%edi
and $0xfffffff0,%esp
pushl -0x4(%edi)
push %ebp
mov %esp,%ebp
so the tracer modifies the copy of the return address which is stored
after the stack alignment and therefor does not trap the return which
in turn breaks the call chain logic of the tracer and leads to a
kernel panic.
Aside of the fact that the generated code is horrible for no good
reason other -march -mtune options generate the expected:
push %ebp
mov %esp,%ebp
and $0xfffffff0,%esp
which does the same and keeps everything intact.
After some experimenting we found out that this problem is restricted
to gcc4.4.x and to the following -march settings:
i586, pentium, pentium-mmx, k6, k6-2, k6-3, winchip-c6, winchip2, c3,
geode
By adding -mtune=generic the code generator produces always the
expected code.
So forcing -mtune=generic when CONFIG_FUNCTION_GRAPH_TRACER=y is not
pretty, but at the moment the only way to prevent that the kernel
trips over gcc-shrooms induced code madness.
Most distro kernels have CONFIG_X86_GENERIC=y anyway which forces
-mtune=generic as well so it will not impact those.
References: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109
http://lkml.org/lkml/2009/11/19/17
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
LKML-Reference: <alpine.LFD.2.00.0911200206570.24119@localhost.localdomain>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
Cc: Jeff Law <law@redhat.com>
Cc: gcc@gcc.gnu.org
Cc: David Daney <ddaney@caviumnetworks.com>
Cc: Andrew Haley <aph@redhat.com>
Cc: Richard Guenther <richard.guenther@gmail.com>
Cc: stable@kernel.org
2009-11-20 19:01:43 +08:00
|
|
|
# Work around the pentium-mmx code generator madness of gcc4.4.x which
|
|
|
|
|
# does stack alignment by generating horrible code _before_ the mcount
|
|
|
|
|
# prologue (push %ebp, mov %esp, %ebp) which breaks the function graph
|
2009-11-28 22:03:03 +08:00
|
|
|
# tracer assumptions. For i686, generic, core2 this is set by the
|
|
|
|
|
# compiler anyway
|
|
|
|
|
cflags-$(CONFIG_FUNCTION_GRAPH_TRACER) += $(call cc-option,-maccumulate-outgoing-args)
|
x86: Prevent GCC 4.4.x (pentium-mmx et al) function prologue wreckage
When the kernel is compiled with -pg for tracing GCC 4.4.x inserts
stack alignment of a function _before_ the mcount prologue if the
-march=pentium-mmx is set and -mtune=generic is not set. This breaks
the assumption of the function graph tracer which expects that the
mcount prologue
push %ebp
mov %esp, %ebp
is the first stack operation in a function because it needs to modify
the function return address on the stack to trap into the tracer
before returning to the real caller.
The generated code is:
push %edi
lea 0x8(%esp),%edi
and $0xfffffff0,%esp
pushl -0x4(%edi)
push %ebp
mov %esp,%ebp
so the tracer modifies the copy of the return address which is stored
after the stack alignment and therefor does not trap the return which
in turn breaks the call chain logic of the tracer and leads to a
kernel panic.
Aside of the fact that the generated code is horrible for no good
reason other -march -mtune options generate the expected:
push %ebp
mov %esp,%ebp
and $0xfffffff0,%esp
which does the same and keeps everything intact.
After some experimenting we found out that this problem is restricted
to gcc4.4.x and to the following -march settings:
i586, pentium, pentium-mmx, k6, k6-2, k6-3, winchip-c6, winchip2, c3,
geode
By adding -mtune=generic the code generator produces always the
expected code.
So forcing -mtune=generic when CONFIG_FUNCTION_GRAPH_TRACER=y is not
pretty, but at the moment the only way to prevent that the kernel
trips over gcc-shrooms induced code madness.
Most distro kernels have CONFIG_X86_GENERIC=y anyway which forces
-mtune=generic as well so it will not impact those.
References: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42109
http://lkml.org/lkml/2009/11/19/17
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
LKML-Reference: <alpine.LFD.2.00.0911200206570.24119@localhost.localdomain>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
Cc: Jeff Law <law@redhat.com>
Cc: gcc@gcc.gnu.org
Cc: David Daney <ddaney@caviumnetworks.com>
Cc: Andrew Haley <aph@redhat.com>
Cc: Richard Guenther <richard.guenther@gmail.com>
Cc: stable@kernel.org
2009-11-20 19:01:43 +08:00
|
|
|
|
2008-09-09 03:01:48 +08:00
|
|
|
# Bug fix for binutils: this option is required in order to keep
|
|
|
|
|
# binutils from generating NOPL instructions against our will.
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ifneq ($(CONFIG_X86_P6_NOP),y)
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cflags-y += $(call cc-option,-Wa$(comma)-mtune=generic32,)
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endif
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