Hi Mark, all.
In patch 'dbc9344a68e506f19f8 ("arm64: clean up THREAD_* definitions")'
you move THREAD_* definitions from arch/arm64/include/asm/thread_info.h
to asm/memory.h. After that asm/thread_info.h starts to depend on
asm/memory.h.
When I try to apply ilp32 series on top of it [1], it causes circular
dependencies like this one:
In file included from ./arch/arm64/include/asm/memory.h:30:0,
from ./arch/arm64/include/asm/thread_info.h:30,
from ./include/linux/thread_bits.h:20,
from ./include/linux/thread_info.h:13,
from ./include/asm-generic/preempt.h:4,
from ./arch/arm64/include/generated/asm/preempt.h:1,
from ./include/linux/preempt.h:80,
from ./include/linux/rcupdate.h:40,
from ./include/linux/rculist.h:10,
from ./include/linux/pid.h:4,
from ./include/linux/sched.h:13,
from arch/arm64/kernel/asm-offsets.c:21:
./arch/arm64/include/asm/is_compat.h: In function ‘is_a32_compat_task’:
./arch/arm64/include/asm/is_compat.h:25:9: error: implicit declaration of function ‘test_thread_flag’ [-Werror=implicit-function-declaration]
return test_thread_flag(TIF_32BIT);
^~~~~~~~~~~~~~~~
The problem is that asm/memory.h depends on asm/is_compat.h to define
TASK_SIZE, which in turn requires asm/thread_info.h.
The most obvious solution for it is to create is_compat.c file and make
is_*_compat() real functions. The other option is to move THREAD_*
definitions to separated macro. I would prefer 2nd one because of following
reasons:
- TASK_SIZE macro is used many times in kernel, including hot paths;
- asm/memory.h is included widely, as well as asm/thread_info.h, and it's
better not to make them depend one from another;
- THREAD_SIZE etc are not memory-related definitions.
In this patch THREAD_* definitions moved to separated asm/thread_size.h
header. It's enough to resolve dependency above.
If you find this approach useful, I can prepare other patch that moves
TASK_* definitions from asm/memory.h to new header to remove the dependency
from asm/is_compat.h.
Also, arch/arm64/kernel/entry.S and arch/arm64/kernel/hibernate-asm.S
#includes list is cleaned.
[1] https://github.com/norov/linux/tree/ilp32-next (still in progress)
CC: Will Deacon <[email protected]>
CC: Laura Abbott <[email protected]>
Cc: Ard Biesheuvel <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: James Morse <[email protected]>
Signed-off-by: Yury Norov <[email protected]>
---
arch/arm64/include/asm/memory.h | 30 +-------------------
arch/arm64/include/asm/thread_info.h | 2 +-
arch/arm64/include/asm/thread_size.h | 53 ++++++++++++++++++++++++++++++++++++
arch/arm64/kernel/entry.S | 2 +-
arch/arm64/kernel/hibernate-asm.S | 1 -
5 files changed, 56 insertions(+), 32 deletions(-)
create mode 100644 arch/arm64/include/asm/thread_size.h
diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
index 0c3ee6afda5b..bc7ec1930659 100644
--- a/arch/arm64/include/asm/memory.h
+++ b/arch/arm64/include/asm/memory.h
@@ -21,6 +21,7 @@
#ifndef __ASM_MEMORY_H
#define __ASM_MEMORY_H
+#include <asm/thread_size.h>
#include <linux/compiler.h>
#include <linux/const.h>
#include <linux/types.h>
@@ -105,35 +106,6 @@
#define KASAN_SHADOW_SIZE (0)
#endif
-#define MIN_THREAD_SHIFT 14
-
-/*
- * VMAP'd stacks are allocated at page granularity, so we must ensure that such
- * stacks are a multiple of page size.
- */
-#if defined(CONFIG_VMAP_STACK) && (MIN_THREAD_SHIFT < PAGE_SHIFT)
-#define THREAD_SHIFT PAGE_SHIFT
-#else
-#define THREAD_SHIFT MIN_THREAD_SHIFT
-#endif
-
-#if THREAD_SHIFT >= PAGE_SHIFT
-#define THREAD_SIZE_ORDER (THREAD_SHIFT - PAGE_SHIFT)
-#endif
-
-#define THREAD_SIZE (UL(1) << THREAD_SHIFT)
-
-/*
- * By aligning VMAP'd stacks to 2 * THREAD_SIZE, we can detect overflow by
- * checking sp & (1 << THREAD_SHIFT), which we can do cheaply in the entry
- * assembly.
- */
-#ifdef CONFIG_VMAP_STACK
-#define THREAD_ALIGN (2 * THREAD_SIZE)
-#else
-#define THREAD_ALIGN THREAD_SIZE
-#endif
-
#define IRQ_STACK_SIZE THREAD_SIZE
#define OVERFLOW_STACK_SIZE SZ_4K
diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
index 5d889c645321..6267ba7bd0e4 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h
@@ -27,7 +27,7 @@
struct task_struct;
-#include <asm/memory.h>
+#include <asm/thread_size.h>
#include <asm/stack_pointer.h>
#include <asm/types.h>
diff --git a/arch/arm64/include/asm/thread_size.h b/arch/arm64/include/asm/thread_size.h
new file mode 100644
index 000000000000..dd0b8906f9de
--- /dev/null
+++ b/arch/arm64/include/asm/thread_size.h
@@ -0,0 +1,53 @@
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __ASM_THREAD_SIZE_H
+#define __ASM_THREAD_SIZE_H
+
+#ifdef __KERNEL__
+
+#include <asm/page-def.h>
+#include <linux/const.h>
+
+#define MIN_THREAD_SHIFT 14
+
+/*
+ * VMAP'd stacks are allocated at page granularity, so we must ensure that such
+ * stacks are a multiple of page size.
+ */
+#if defined(CONFIG_VMAP_STACK) && (MIN_THREAD_SHIFT < PAGE_SHIFT)
+#define THREAD_SHIFT PAGE_SHIFT
+#else
+#define THREAD_SHIFT MIN_THREAD_SHIFT
+#endif
+
+#if THREAD_SHIFT >= PAGE_SHIFT
+#define THREAD_SIZE_ORDER (THREAD_SHIFT - PAGE_SHIFT)
+#endif
+
+#define THREAD_SIZE (_AC(1, UL) << THREAD_SHIFT)
+
+/*
+ * By aligning VMAP'd stacks to 2 * THREAD_SIZE, we can detect overflow by
+ * checking sp & (1 << THREAD_SHIFT), which we can do cheaply in the entry
+ * assembly.
+ */
+#ifdef CONFIG_VMAP_STACK
+#define THREAD_ALIGN (2 * THREAD_SIZE)
+#else
+#define THREAD_ALIGN THREAD_SIZE
+#endif
+
+#endif /* __KERNEL__ */
+#endif /*__ASM_THREAD_SIZE_H */
diff --git a/arch/arm64/kernel/entry.S b/arch/arm64/kernel/entry.S
index 84b9f1d235ba..43f8ea210bb3 100644
--- a/arch/arm64/kernel/entry.S
+++ b/arch/arm64/kernel/entry.S
@@ -28,7 +28,7 @@
#include <asm/errno.h>
#include <asm/esr.h>
#include <asm/irq.h>
-#include <asm/memory.h>
+#include <asm/thread_size.h>
#include <asm/ptrace.h>
#include <asm/thread_info.h>
#include <asm/asm-uaccess.h>
diff --git a/arch/arm64/kernel/hibernate-asm.S b/arch/arm64/kernel/hibernate-asm.S
index e56d848b6466..46b91702ea26 100644
--- a/arch/arm64/kernel/hibernate-asm.S
+++ b/arch/arm64/kernel/hibernate-asm.S
@@ -22,7 +22,6 @@
#include <asm/asm-offsets.h>
#include <asm/assembler.h>
#include <asm/cputype.h>
-#include <asm/memory.h>
#include <asm/page.h>
#include <asm/virt.h>
--
2.11.0
On Wed, Aug 30, 2017 at 12:22:49PM +0300, Yury Norov wrote:
> Hi Mark, all.
Hi Yury,
> In patch 'dbc9344a68e506f19f8 ("arm64: clean up THREAD_* definitions")'
> you move THREAD_* definitions from arch/arm64/include/asm/thread_info.h
> to asm/memory.h. After that asm/thread_info.h starts to depend on
> asm/memory.h.
>
> When I try to apply ilp32 series on top of it [1], it causes circular
> dependencies like this one:
>
> In file included from ./arch/arm64/include/asm/memory.h:30:0,
> from ./arch/arm64/include/asm/thread_info.h:30,
> from ./include/linux/thread_bits.h:20,
> from ./include/linux/thread_info.h:13,
> from ./include/asm-generic/preempt.h:4,
> from ./arch/arm64/include/generated/asm/preempt.h:1,
> from ./include/linux/preempt.h:80,
> from ./include/linux/rcupdate.h:40,
> from ./include/linux/rculist.h:10,
> from ./include/linux/pid.h:4,
> from ./include/linux/sched.h:13,
> from arch/arm64/kernel/asm-offsets.c:21:
> ./arch/arm64/include/asm/is_compat.h: In function ‘is_a32_compat_task’:
> ./arch/arm64/include/asm/is_compat.h:25:9: error: implicit declaration of function ‘test_thread_flag’ [-Werror=implicit-function-declaration]
> return test_thread_flag(TIF_32BIT);
> ^~~~~~~~~~~~~~~~
>
> The problem is that asm/memory.h depends on asm/is_compat.h to define
> TASK_SIZE, which in turn requires asm/thread_info.h.
... and <asm/thread_info.h> include <asm/memory.h>, giving a circular
dependency.
In other architectures, TASK_SIZE is defined in processor.h. Can we not
move TASK_SIZE instead of THREAD_SIZE, given that TASK_SIZE is what
causes the dependency?
We'd need a new __ASSEMBLY__ guard, but otherwise it looks like that
would solve the issue.
> The most obvious solution for it is to create is_compat.c file and make
> is_*_compat() real functions. The other option is to move THREAD_*
> definitions to separated macro. I would prefer 2nd one because of following
> reasons:
> - TASK_SIZE macro is used many times in kernel, including hot paths;
> - asm/memory.h is included widely, as well as asm/thread_info.h, and it's
> better not to make them depend one from another;
> - THREAD_SIZE etc are not memory-related definitions.
I disagree with this last point. THREAD_SIZE is in <asm/memory.h>
because it affects the kernel's memory layout, as with other definitions
at the top of <asm/memory.h>.
I would much prefer keeping those definitions together.
> In this patch THREAD_* definitions moved to separated asm/thread_size.h
> header. It's enough to resolve dependency above.
>
> If you find this approach useful, I can prepare other patch that moves
> TASK_* definitions from asm/memory.h to new header to remove the dependency
> from asm/is_compat.h.
I'd prefer that we moved the TASK_SIZE* definitions first, but if
necessary, I'm ok with seeing the THREAD_SIZE* definitions move.
[...]
> diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
> -#include <asm/memory.h>
> +#include <asm/thread_size.h>
> #include <asm/stack_pointer.h>
> #include <asm/types.h>
Nit: please keep includes ordered alphabetically.
[...]
> diff --git a/arch/arm64/include/asm/thread_size.h b/arch/arm64/include/asm/thread_size.h
> +#ifdef __KERNEL__
This can go. We haven't needed __KERNEL__ ifdefs for a long time now...
[...]
> diff --git a/arch/arm64/kernel/hibernate-asm.S b/arch/arm64/kernel/hibernate-asm.S
> index e56d848b6466..46b91702ea26 100644
> --- a/arch/arm64/kernel/hibernate-asm.S
> +++ b/arch/arm64/kernel/hibernate-asm.S
> @@ -22,7 +22,6 @@
> #include <asm/asm-offsets.h>
> #include <asm/assembler.h>
> #include <asm/cputype.h>
> -#include <asm/memory.h>
> #include <asm/page.h>
> #include <asm/virt.h>
AFAICT, we can also lose <linux/errno.h>, <asm/cputype.h>, and
<asm/virt.h>.
Changes to this file might be better as a preparatory cleanup.
Thanks,
Mark.
On Wed, Aug 30, 2017 at 10:58:54AM +0100, Mark Rutland wrote:
> On Wed, Aug 30, 2017 at 12:22:49PM +0300, Yury Norov wrote:
> > Hi Mark, all.
>
> Hi Yury,
>
> > In patch 'dbc9344a68e506f19f8 ("arm64: clean up THREAD_* definitions")'
> > you move THREAD_* definitions from arch/arm64/include/asm/thread_info.h
> > to asm/memory.h. After that asm/thread_info.h starts to depend on
> > asm/memory.h.
> >
> > When I try to apply ilp32 series on top of it [1], it causes circular
> > dependencies like this one:
> >
> > In file included from ./arch/arm64/include/asm/memory.h:30:0,
> > from ./arch/arm64/include/asm/thread_info.h:30,
> > from ./include/linux/thread_bits.h:20,
> > from ./include/linux/thread_info.h:13,
> > from ./include/asm-generic/preempt.h:4,
> > from ./arch/arm64/include/generated/asm/preempt.h:1,
> > from ./include/linux/preempt.h:80,
> > from ./include/linux/rcupdate.h:40,
> > from ./include/linux/rculist.h:10,
> > from ./include/linux/pid.h:4,
> > from ./include/linux/sched.h:13,
> > from arch/arm64/kernel/asm-offsets.c:21:
> > ./arch/arm64/include/asm/is_compat.h: In function ‘is_a32_compat_task’:
> > ./arch/arm64/include/asm/is_compat.h:25:9: error: implicit declaration of function ‘test_thread_flag’ [-Werror=implicit-function-declaration]
> > return test_thread_flag(TIF_32BIT);
> > ^~~~~~~~~~~~~~~~
> >
> > The problem is that asm/memory.h depends on asm/is_compat.h to define
> > TASK_SIZE, which in turn requires asm/thread_info.h.
>
> ... and <asm/thread_info.h> include <asm/memory.h>, giving a circular
> dependency.
>
> In other architectures, TASK_SIZE is defined in processor.h. Can we not
> move TASK_SIZE instead of THREAD_SIZE, given that TASK_SIZE is what
> causes the dependency?
>
> We'd need a new __ASSEMBLY__ guard, but otherwise it looks like that
> would solve the issue.
>
> > The most obvious solution for it is to create is_compat.c file and make
> > is_*_compat() real functions. The other option is to move THREAD_*
> > definitions to separated macro. I would prefer 2nd one because of following
> > reasons:
> > - TASK_SIZE macro is used many times in kernel, including hot paths;
> > - asm/memory.h is included widely, as well as asm/thread_info.h, and it's
> > better not to make them depend one from another;
> > - THREAD_SIZE etc are not memory-related definitions.
>
> I disagree with this last point. THREAD_SIZE is in <asm/memory.h>
> because it affects the kernel's memory layout, as with other definitions
> at the top of <asm/memory.h>.
>
> I would much prefer keeping those definitions together.
>
> > In this patch THREAD_* definitions moved to separated asm/thread_size.h
> > header. It's enough to resolve dependency above.
> >
> > If you find this approach useful, I can prepare other patch that moves
> > TASK_* definitions from asm/memory.h to new header to remove the dependency
> > from asm/is_compat.h.
>
> I'd prefer that we moved the TASK_SIZE* definitions first, but if
> necessary, I'm ok with seeing the THREAD_SIZE* definitions move.
OK, I will try this, and if it's be enough will send new patch. If not -
I'll resend this patch and one that moves TASK_SIZE* together in series.
> [...]
>
> > diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
>
> > -#include <asm/memory.h>
> > +#include <asm/thread_size.h>
> > #include <asm/stack_pointer.h>
> > #include <asm/types.h>
>
> Nit: please keep includes ordered alphabetically.
OK
> [...]
>
> > diff --git a/arch/arm64/include/asm/thread_size.h b/arch/arm64/include/asm/thread_size.h
>
> > +#ifdef __KERNEL__
>
> This can go. We haven't needed __KERNEL__ ifdefs for a long time now...
OK
> [...]
>
> > diff --git a/arch/arm64/kernel/hibernate-asm.S b/arch/arm64/kernel/hibernate-asm.S
> > index e56d848b6466..46b91702ea26 100644
> > --- a/arch/arm64/kernel/hibernate-asm.S
> > +++ b/arch/arm64/kernel/hibernate-asm.S
> > @@ -22,7 +22,6 @@
> > #include <asm/asm-offsets.h>
> > #include <asm/assembler.h>
> > #include <asm/cputype.h>
> > -#include <asm/memory.h>
> > #include <asm/page.h>
> > #include <asm/virt.h>
>
> AFAICT, we can also lose <linux/errno.h>, <asm/cputype.h>, and
> <asm/virt.h>.
>
> Changes to this file might be better as a preparatory cleanup.
OK.
Yury