[PATCH v4 00/26] Introduce common headers for vDSO

[Vincenzo Frascino]

Back in July last year we started having a problem in building compat
vDSOs on arm64 [1] [2] that was not present when the arm64 porting to
the Unified vDSO was done. In particular when the compat vDSO on such
architecture is built with gcc it generates the warning below:

In file included from ./arch/arm64/include/asm/thread_info.h:17:0,
from ./include/linux/thread_info.h:38,
from ./arch/arm64/include/asm/preempt.h:5,
from ./include/linux/preempt.h:78,
from ./include/linux/spinlock.h:51,
from ./include/linux/seqlock.h:36,
from ./include/linux/time.h:6,
from ./lib/vdso/gettimeofday.c:7,
from <command-line>:0:
./arch/arm64/include/asm/memory.h: In function ‘__tag_set’:
./arch/arm64/include/asm/memory.h:233:15: warning: cast from pointer
to integer of different size [-Wpointer-to-int-cast]
u64 __addr = (u64)addr & ~__tag_shifted(0xff);
^
In file included from ./arch/arm64/include/asm/pgtable-hwdef.h:8:0,
from ./arch/arm64/include/asm/processor.h:34,
from ./arch/arm64/include/asm/elf.h:118,
from ./include/linux/elf.h:5,
from ./include/linux/elfnote.h:62,
from arch/arm64/kernel/vdso32/note.c:11:
./arch/arm64/include/asm/memory.h: In function ‘__tag_set’:
./arch/arm64/include/asm/memory.h:233:15: warning: cast from pointer
to integer of different size [-Wpointer-to-int-cast]
u64 __addr = (u64)addr & ~__tag_shifted(0xff);

The same porting does not build at all when the selected compiler is
clang.

I started an investigation to try to understand better the problem and
after various discussions at Plumbers and Recipes last year the
conclusion was that the vDSO library as it stands it is including more
headers that it needs. In particular, being a user-space library, it
should require only the UAPI and a minimal vDSO kernel interface instead
of all the kernel-related inline functions which are not directly used
and in some cases can have side effects.

To solve the problem, I decided to use the approach below:
* Extract from include/linux/ the vDSO required kernel interface
and place it in include/vdso/
* Make sure that where meaningful the kernel includes "vdso" headers.
* Limit the vDSO library to include headers coming only from UAPI
and "vdso" (with 2 exceptions compiler.h for barriers and param.h
for HZ).
* Adapt all the architectures that support the unified vDSO library
to use "vdso" headers.

According to me this approach allows up to exercise a better control on
what the vDSO library can include and to prevent potential issues in
future.

This patch series contains the implementation of the described approach.

The "vdso" headers have been verified on all the architectures that support
unified vDSO using the vdsotest [3] testsuite for what concerns the vDSO part
and randconfig to verify that they are included in the correct places.

To simplify the testing, a copy of the patchset on top of a recent linux
tree can be found at [4].

[1] https://github.com/ClangBuiltLinux/linux/issues/595
[2] https://lore.kernel.org/lkml/***@arrakis.emea.arm.com
[3] https://github.com/nathanlynch/vdsotest
[4] git://linux-arm.org/linux-vf.git common-headers/v4

Changes:
--------
v4:
- Dropped vDSO optimization patch for arm64.
- Introduce a new patch to drop dependency from TASK_SIZE_32 on arm64.
- Addressed review comments.
- Rebased on tip/timers/core.
v3:
- Changed the namespace from common to vdso.
- Addressed an issue involving parisc modules compilation.
- Added vdso header for clocksource.h.
- Addressed review comments.
- Rebased on tip/timers/core.
v2:
- Addressed review comments for clang support.
- Rebased on 5.6-rc4.

Cc: Catalin Marinas <***@arm.com>
Cc: Will Deacon <***@arm.com>
Cc: Arnd Bergmann <***@arndb.de>
Cc: Russell King <***@armlinux.org.uk>
Cc: Paul Burton <***@mips.com>
Cc: Thomas Gleixner <***@linutronix.de>
Cc: Andy Lutomirski <***@kernel.org>
Cc: Ingo Molnar <***@redhat.com>
Cc: Borislav Petkov <***@alien8.de>
Cc: Stephen Boyd <***@kernel.org>
Cc: Mark Salyzyn <***@android.com>
Cc: Kees Cook <***@chromium.org>
Cc: Peter Collingbourne <***@google.com>
Cc: Dmitry Safonov <***@gmail.com>
Cc: Andrei Vagin <***@openvz.org>
Cc: Nick Desaulniers <***@google.com>
Cc: Marc Zyngier <***@kernel.org>
Cc: Mark Rutland <***@arm.com>
Signed-off-by: Vincenzo Frascino <***@arm.com>

Vincenzo Frascino (26):
linux/const.h: Extract common header for vDSO
linux/bits.h: Extract common header for vDSO
linux/limits.h: Extract common header for vDSO
x86:Introduce asm/vdso/clocksource.h
arm: Introduce asm/vdso/clocksource.h
arm64: Introduce asm/vdso/clocksource.h
mips: Introduce asm/vdso/clocksource.h
linux/clocksource.h: Extract common header for vDSO
linux/math64.h: Extract common header for vDSO
linux/time.h: Extract common header for vDSO
linux/time32.h: Extract common header for vDSO
linux/time64.h: Extract common header for vDSO
linux/jiffies.h: Extract common header for vDSO
linux/ktime.h: Extract common header for vDSO
common: Introduce processor.h
scripts: Fix the inclusion order in modpost
linux/elfnote.h: Replace elf.h with UAPI equivalent
arm64: vdso32: Replace TASK_SIZE_32 check in vgettimeofday
arm64: Introduce asm/vdso/processor.h
arm64: vdso: Include common headers in the vdso library
arm64: vdso32: Include common headers in the vdso library
mips: vdso: Enable mips to use common headers
x86: vdso: Enable x86 to use common headers
arm: vdso: Enable arm to use common headers
lib: vdso: Enable common headers
arm64: vdso32: Enable Clang Compilation

arch/arm/include/asm/clocksource.h | 6 +--
arch/arm/include/asm/cp15.h | 20 +---------
arch/arm/include/asm/processor.h | 11 +-----
arch/arm/include/asm/vdso/clocksource.h | 8 ++++
arch/arm/include/asm/vdso/cp15.h | 38 +++++++++++++++++++
arch/arm/include/asm/vdso/gettimeofday.h | 4 +-
arch/arm/include/asm/vdso/processor.h | 22 +++++++++++
arch/arm64/include/asm/clocksource.h | 3 +-
arch/arm64/include/asm/processor.h | 7 +---
arch/arm64/include/asm/vdso/clocksource.h | 8 ++++
.../include/asm/vdso/compat_gettimeofday.h | 2 +-
arch/arm64/include/asm/vdso/gettimeofday.h | 1 -
arch/arm64/include/asm/vdso/processor.h | 17 +++++++++
arch/arm64/kernel/vdso/vgettimeofday.c | 2 -
arch/arm64/kernel/vdso32/Makefile | 11 ++++++
arch/arm64/kernel/vdso32/vgettimeofday.c | 13 ++++---
arch/mips/include/asm/clocksource.h | 4 +-
arch/mips/include/asm/processor.h | 16 +-------
arch/mips/include/asm/vdso/clocksource.h | 9 +++++
arch/mips/include/asm/vdso/gettimeofday.h | 4 --
arch/mips/include/asm/vdso/processor.h | 27 +++++++++++++
arch/x86/include/asm/clocksource.h | 5 +--
arch/x86/include/asm/processor.h | 12 +-----
arch/x86/include/asm/vdso/clocksource.h | 10 +++++
arch/x86/include/asm/vdso/processor.h | 23 +++++++++++
include/linux/bits.h | 2 +-
include/linux/clocksource.h | 11 +-----
include/linux/const.h | 5 +--
include/linux/elfnote.h | 2 +-
include/linux/jiffies.h | 4 +-
include/linux/ktime.h | 9 +----
include/linux/limits.h | 13 +------
include/linux/math64.h | 20 +---------
include/linux/time.h | 5 +--
include/linux/time32.h | 14 +------
include/linux/time64.h | 10 +----
include/vdso/bits.h | 9 +++++
include/vdso/clocksource.h | 23 +++++++++++
include/vdso/const.h | 10 +++++
include/vdso/datapage.h | 33 ++++++++++++++--
include/vdso/jiffies.h | 11 ++++++
include/vdso/ktime.h | 16 ++++++++
include/vdso/limits.h | 19 ++++++++++
include/vdso/math64.h | 24 ++++++++++++
include/vdso/processor.h | 14 +++++++
include/vdso/time.h | 12 ++++++
include/vdso/time32.h | 17 +++++++++
include/vdso/time64.h | 14 +++++++
lib/vdso/gettimeofday.c | 22 -----------
scripts/mod/modpost.c | 6 ++-
50 files changed, 412 insertions(+), 196 deletions(-)
create mode 100644 arch/arm/include/asm/vdso/clocksource.h
create mode 100644 arch/arm/include/asm/vdso/cp15.h
create mode 100644 arch/arm/include/asm/vdso/processor.h
create mode 100644 arch/arm64/include/asm/vdso/clocksource.h
create mode 100644 arch/arm64/include/asm/vdso/processor.h
create mode 100644 arch/mips/include/asm/vdso/clocksource.h
create mode 100644 arch/mips/include/asm/vdso/processor.h
create mode 100644 arch/x86/include/asm/vdso/clocksource.h
create mode 100644 arch/x86/include/asm/vdso/processor.h
create mode 100644 include/vdso/bits.h
create mode 100644 include/vdso/clocksource.h
create mode 100644 include/vdso/const.h
create mode 100644 include/vdso/jiffies.h
create mode 100644 include/vdso/ktime.h
create mode 100644 include/vdso/limits.h
create mode 100644 include/vdso/math64.h
create mode 100644 include/vdso/processor.h
create mode 100644 include/vdso/time.h
create mode 100644 include/vdso/time32.h
create mode 100644 include/vdso/time64.h

[Vincenzo Frascino]

The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.

Split const.h into linux and common headers to make the latter suitable
for inclusion in the vDSO library.

Signed-off-by: Vincenzo Frascino <***@arm.com>
---
include/linux/const.h | 5 +----
include/vdso/const.h | 10 ++++++++++
2 files changed, 11 insertions(+), 4 deletions(-)
create mode 100644 include/vdso/const.h

diff --git a/include/linux/const.h b/include/linux/const.h
index 7b55a55f5911..81b8aae5a855 100644
--- a/include/linux/const.h
+++ b/include/linux/const.h
@@ -1,9 +1,6 @@
#ifndef _LINUX_CONST_H
#define _LINUX_CONST_H

-#include <uapi/linux/const.h>
-
-#define UL(x) (_UL(x))
-#define ULL(x) (_ULL(x))
+#include <vdso/const.h>

#endif /* _LINUX_CONST_H */
diff --git a/include/vdso/const.h b/include/vdso/const.h
new file mode 100644
index 000000000000..94b385ad438d
--- /dev/null
+++ b/include/vdso/const.h
@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __VDSO_CONST_H
+#define __VDSO_CONST_H
+
+#include <uapi/linux/const.h>
+
+#define UL(x) (_UL(x))
+#define ULL(x) (_ULL(x))
+
+#endif /* __VDSO_CONST_H */

[Vincenzo Frascino]

The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.

Split bits.h into linux and common headers to make the latter suitable
for inclusion in the vDSO library.

Signed-off-by: Vincenzo Frascino <***@arm.com>
---
include/linux/bits.h | 2 +-
include/vdso/bits.h | 9 +++++++++
2 files changed, 10 insertions(+), 1 deletion(-)
create mode 100644 include/vdso/bits.h

diff --git a/include/linux/bits.h b/include/linux/bits.h
index 669d69441a62..a740bbcf3cd2 100644
--- a/include/linux/bits.h
+++ b/include/linux/bits.h
@@ -3,9 +3,9 @@
#define __LINUX_BITS_H

#include <linux/const.h>
+#include <vdso/bits.h>
#include <asm/bitsperlong.h>

-#define BIT(nr) (UL(1) << (nr))
#define BIT_ULL(nr) (ULL(1) << (nr))
#define BIT_MASK(nr) (UL(1) << ((nr) % BITS_PER_LONG))
#define BIT_WORD(nr) ((nr) / BITS_PER_LONG)
diff --git a/include/vdso/bits.h b/include/vdso/bits.h
new file mode 100644
index 000000000000..6d005a1f5d94
--- /dev/null
+++ b/include/vdso/bits.h
@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __VDSO_BITS_H
+#define __VDSO_BITS_H
+
+#include <vdso/const.h>
+
+#define BIT(nr) (UL(1) << (nr))
+
+#endif /* __VDSO_BITS_H */

[Vincenzo Frascino]

The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.

Split limits.h into linux and common headers to make the latter suitable
for inclusion in the vDSO library.

Signed-off-by: Vincenzo Frascino <***@arm.com>
---
include/linux/limits.h | 13 +------------
include/vdso/limits.h | 19 +++++++++++++++++++
2 files changed, 20 insertions(+), 12 deletions(-)
create mode 100644 include/vdso/limits.h

diff --git a/include/linux/limits.h b/include/linux/limits.h
index 76afcd24ff8c..7fc497ee1393 100644
--- a/include/linux/limits.h
+++ b/include/linux/limits.h
@@ -4,19 +4,8 @@

#include <uapi/linux/limits.h>
#include <linux/types.h>
+#include <vdso/limits.h>

-#define USHRT_MAX ((unsigned short)~0U)
-#define SHRT_MAX ((short)(USHRT_MAX >> 1))
-#define SHRT_MIN ((short)(-SHRT_MAX - 1))
-#define INT_MAX ((int)(~0U >> 1))
-#define INT_MIN (-INT_MAX - 1)
-#define UINT_MAX (~0U)
-#define LONG_MAX ((long)(~0UL >> 1))
-#define LONG_MIN (-LONG_MAX - 1)
-#define ULONG_MAX (~0UL)
-#define LLONG_MAX ((long long)(~0ULL >> 1))
-#define LLONG_MIN (-LLONG_MAX - 1)
-#define ULLONG_MAX (~0ULL)
#define SIZE_MAX (~(size_t)0)
#define PHYS_ADDR_MAX (~(phys_addr_t)0)

diff --git a/include/vdso/limits.h b/include/vdso/limits.h
new file mode 100644
index 000000000000..0197888ad0e0
--- /dev/null
+++ b/include/vdso/limits.h
@@ -0,0 +1,19 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __VDSO_LIMITS_H
+#define __VDSO_LIMITS_H
+
+#define USHRT_MAX ((unsigned short)~0U)
+#define SHRT_MAX ((short)(USHRT_MAX >> 1))
+#define SHRT_MIN ((short)(-SHRT_MAX - 1))
+#define INT_MAX ((int)(~0U >> 1))
+#define INT_MIN (-INT_MAX - 1)
+#define UINT_MAX (~0U)
+#define LONG_MAX ((long)(~0UL >> 1))
+#define LONG_MIN (-LONG_MAX - 1)
+#define ULONG_MAX (~0UL)
+#define LLONG_MAX ((long long)(~0ULL >> 1))
+#define LLONG_MIN (-LLONG_MAX - 1)
+#define ULLONG_MAX (~0ULL)
+#define UINTPTR_MAX ULONG_MAX
+
+#endif /* __VDSO_LIMITS_H */

[Vincenzo Frascino]

The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.

Introduce asm/vdso/clocksource.h to contain all the arm64 specific
functions that are suitable for vDSO inclusion.

This header will be required by a future patch that will generalize
vdso/clocksource.h.

Cc: Thomas Gleixner <***@linutronix.de>
Cc: Andy Lutomirski <***@kernel.org>
Cc: Ingo Molnar <***@redhat.com>
Cc: Borislav Petkov <***@alien8.de>
Signed-off-by: Vincenzo Frascino <***@arm.com>
---
arch/x86/include/asm/clocksource.h | 5 +----
arch/x86/include/asm/vdso/clocksource.h | 10 ++++++++++
2 files changed, 11 insertions(+), 4 deletions(-)
create mode 100644 arch/x86/include/asm/vdso/clocksource.h

diff --git a/arch/x86/include/asm/clocksource.h b/arch/x86/include/asm/clocksource.h
index d561db67f96d..dc9dc7b3911a 100644
--- a/arch/x86/include/asm/clocksource.h
+++ b/arch/x86/include/asm/clocksource.h
@@ -4,10 +4,7 @@
#ifndef _ASM_X86_CLOCKSOURCE_H
#define _ASM_X86_CLOCKSOURCE_H

-#define VDSO_ARCH_CLOCKMODES \
- VDSO_CLOCKMODE_TSC, \
- VDSO_CLOCKMODE_PVCLOCK, \
- VDSO_CLOCKMODE_HVCLOCK
+#include <asm/vdso/clocksource.h>

extern unsigned int vclocks_used;

diff --git a/arch/x86/include/asm/vdso/clocksource.h b/arch/x86/include/asm/vdso/clocksource.h
new file mode 100644
index 000000000000..119ac8612d89
--- /dev/null
+++ b/arch/x86/include/asm/vdso/clocksource.h
@@ -0,0 +1,10 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ASM_VDSO_CLOCKSOURCE_H
+#define __ASM_VDSO_CLOCKSOURCE_H
+
+#define VDSO_ARCH_CLOCKMODES \
+ VDSO_CLOCKMODE_TSC, \
+ VDSO_CLOCKMODE_PVCLOCK, \
+ VDSO_CLOCKMODE_HVCLOCK
+
+#endif /* __ASM_VDSO_CLOCKSOURCE_H */

[Vincenzo Frascino]

The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.

Introduce asm/vdso/clocksource.h to contain all the arm64 specific
functions that are suitable for vDSO inclusion.

This header will be required by a future patch that will generalize
vdso/clocksource.h.

Cc: Catalin Marinas <***@arm.com>
Cc: Will Deacon <***@kernel.org>
Acked-by: Catalin Marinas <***@arm.com>
Signed-off-by: Vincenzo Frascino <***@arm.com>
---
arch/arm64/include/asm/clocksource.h | 3 +--
arch/arm64/include/asm/vdso/clocksource.h | 8 ++++++++
2 files changed, 9 insertions(+), 2 deletions(-)
create mode 100644 arch/arm64/include/asm/vdso/clocksource.h

diff --git a/arch/arm64/include/asm/clocksource.h b/arch/arm64/include/asm/clocksource.h
index eb82e9d95c5d..482185566b0c 100644
--- a/arch/arm64/include/asm/clocksource.h
+++ b/arch/arm64/include/asm/clocksource.h
@@ -2,7 +2,6 @@
#ifndef _ASM_CLOCKSOURCE_H
#define _ASM_CLOCKSOURCE_H

-#define VDSO_ARCH_CLOCKMODES \
- VDSO_CLOCKMODE_ARCHTIMER
+#include <asm/vdso/clocksource.h>

#endif
diff --git a/arch/arm64/include/asm/vdso/clocksource.h b/arch/arm64/include/asm/vdso/clocksource.h
new file mode 100644
index 000000000000..df6ea65c1dec
--- /dev/null
+++ b/arch/arm64/include/asm/vdso/clocksource.h
@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ASM_VDSOCLOCKSOURCE_H
+#define __ASM_VDSOCLOCKSOURCE_H
+
+#define VDSO_ARCH_CLOCKMODES \
+ VDSO_CLOCKMODE_ARCHTIMER
+
+#endif

[Vincenzo Frascino]

The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.

Introduce asm/vdso/clocksource.h to contain all the arm64 specific
functions that are suitable for vDSO inclusion.

This header will be required by a future patch that will generalize
vdso/clocksource.h.

Cc: Paul Burton <***@kernel.org>
Signed-off-by: Vincenzo Frascino <***@arm.com>
---
arch/mips/include/asm/clocksource.h | 4 +---
arch/mips/include/asm/vdso/clocksource.h | 9 +++++++++
2 files changed, 10 insertions(+), 3 deletions(-)
create mode 100644 arch/mips/include/asm/vdso/clocksource.h

diff --git a/arch/mips/include/asm/clocksource.h b/arch/mips/include/asm/clocksource.h
index de659cae0d4e..2f1ebbea3d72 100644
--- a/arch/mips/include/asm/clocksource.h
+++ b/arch/mips/include/asm/clocksource.h
@@ -6,8 +6,6 @@
#ifndef __ASM_CLOCKSOURCE_H
#define __ASM_CLOCKSOURCE_H

-#define VDSO_ARCH_CLOCKMODES \
- VDSO_CLOCKMODE_R4K, \
- VDSO_CLOCKMODE_GIC
+#include <asm/vdso/clocksource.h>

#endif /* __ASM_CLOCKSOURCE_H */
diff --git a/arch/mips/include/asm/vdso/clocksource.h b/arch/mips/include/asm/vdso/clocksource.h
new file mode 100644
index 000000000000..510e1671d898
--- /dev/null
+++ b/arch/mips/include/asm/vdso/clocksource.h
@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef __ASM_VDSOCLOCKSOURCE_H
+#define __ASM_VDSOCLOCKSOURCE_H
+
+#define VDSO_ARCH_CLOCKMODES \
+ VDSO_CLOCKMODE_R4K, \
+ VDSO_CLOCKMODE_GIC
+
+#endif /* __ASM_VDSOCLOCKSOURCE_H */

[Vincenzo Frascino]

The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.

Split clocksource.h into linux and common headers to make the latter
suitable for inclusion in the vDSO library.

Signed-off-by: Vincenzo Frascino <***@arm.com>
---
include/linux/clocksource.h | 11 +----------
include/vdso/clocksource.h | 23 +++++++++++++++++++++++
2 files changed, 24 insertions(+), 10 deletions(-)
create mode 100644 include/vdso/clocksource.h

diff --git a/include/linux/clocksource.h b/include/linux/clocksource.h
index 02e3282719bd..86d143db6523 100644
--- a/include/linux/clocksource.h
+++ b/include/linux/clocksource.h
@@ -28,16 +28,7 @@ struct module;
#include <asm/clocksource.h>
#endif

-enum vdso_clock_mode {
- VDSO_CLOCKMODE_NONE,
-#ifdef CONFIG_GENERIC_GETTIMEOFDAY
- VDSO_ARCH_CLOCKMODES,
-#endif
- VDSO_CLOCKMODE_MAX,
-
- /* Indicator for time namespace VDSO */
- VDSO_CLOCKMODE_TIMENS = INT_MAX
-};
+#include <vdso/clocksource.h>

/**
* struct clocksource - hardware abstraction for a free running counter
diff --git a/include/vdso/clocksource.h b/include/vdso/clocksource.h
new file mode 100644
index 000000000000..ab58330e4e5d
--- /dev/null
+++ b/include/vdso/clocksource.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __VDSO_CLOCKSOURCE_H
+#define __VDSO_CLOCKSOURCE_H
+
+#include <vdso/limits.h>
+
+#if defined(CONFIG_ARCH_CLOCKSOURCE_DATA) || \
+ defined(CONFIG_GENERIC_GETTIMEOFDAY)
+#include <asm/vdso/clocksource.h>
+#endif /* CONFIG_ARCH_CLOCKSOURCE_DATA || CONFIG_GENERIC_GETTIMEOFDAY */
+
+enum vdso_clock_mode {
+ VDSO_CLOCKMODE_NONE,
+#ifdef CONFIG_GENERIC_GETTIMEOFDAY
+ VDSO_ARCH_CLOCKMODES,
+#endif
+ VDSO_CLOCKMODE_MAX,
+
+ /* Indicator for time namespace VDSO */
+ VDSO_CLOCKMODE_TIMENS = INT_MAX
+};
+
+#endif /* __VDSO_CLOCKSOURCE_H */

[Vincenzo Frascino]

The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.

Introduce asm/vdso/clocksource.h to contain all the arm64 specific
functions that are suitable for vDSO inclusion.

This header will be required by a future patch that will generalize
vdso/clocksource.h.

Cc: Russell King <***@armlinux.org.uk>
Signed-off-by: Vincenzo Frascino <***@arm.com>
---
arch/arm/include/asm/clocksource.h | 6 +++---
arch/arm/include/asm/vdso/clocksource.h | 8 ++++++++
2 files changed, 11 insertions(+), 3 deletions(-)
create mode 100644 arch/arm/include/asm/vdso/clocksource.h

diff --git a/arch/arm/include/asm/clocksource.h b/arch/arm/include/asm/clocksource.h
index 73beb7f131de..13651c731a81 100644
--- a/arch/arm/include/asm/clocksource.h
+++ b/arch/arm/include/asm/clocksource.h
@@ -1,7 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_CLOCKSOURCE_H
#define _ASM_CLOCKSOURCE_H

-#define VDSO_ARCH_CLOCKMODES \
- VDSO_CLOCKMODE_ARCHTIMER
+#include <asm/vdso/clocksource.h>

-#endif
+#endif /* _ASM_CLOCKSOURCE_H */
diff --git a/arch/arm/include/asm/vdso/clocksource.h b/arch/arm/include/asm/vdso/clocksource.h
new file mode 100644
index 000000000000..50c0b19fb755
--- /dev/null
+++ b/arch/arm/include/asm/vdso/clocksource.h
@@ -0,0 +1,8 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __ASM_VDSOCLOCKSOURCE_H
+#define __ASM_VDSOCLOCKSOURCE_H
+
+#define VDSO_ARCH_CLOCKMODES \
+ VDSO_CLOCKMODE_ARCHTIMER
+
+#endif /* __ASM_VDSOCLOCKSOURCE_H */

[Vincenzo Frascino]

The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.

Split math64.h into linux and common headers to make the latter suitable
for inclusion in the vDSO library.

Signed-off-by: Vincenzo Frascino <***@arm.com>
---
include/linux/math64.h | 20 +-------------------
include/vdso/math64.h | 24 ++++++++++++++++++++++++
2 files changed, 25 insertions(+), 19 deletions(-)
create mode 100644 include/vdso/math64.h

diff --git a/include/linux/math64.h b/include/linux/math64.h
index 65bef21cdddb..11a267413e8e 100644
--- a/include/linux/math64.h
+++ b/include/linux/math64.h
@@ -3,6 +3,7 @@
#define _LINUX_MATH64_H

#include <linux/types.h>
+#include <vdso/math64.h>
#include <asm/div64.h>

#if BITS_PER_LONG == 64
@@ -142,25 +143,6 @@ static inline s64 div_s64(s64 dividend, s32 divisor)

u32 iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder);

-static __always_inline u32
-__iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder)
-{
- u32 ret = 0;
-
- while (dividend >= divisor) {
- /* The following asm() prevents the compiler from
- optimising this loop into a modulo operation. */
- asm("" : "+rm"(dividend));
-
- dividend -= divisor;
- ret++;
- }
-
- *remainder = dividend;
-
- return ret;
-}
-
#ifndef mul_u32_u32
/*
* Many a GCC version messes this up and generates a 64x64 mult :-(
diff --git a/include/vdso/math64.h b/include/vdso/math64.h
new file mode 100644
index 000000000000..7da703ee5561
--- /dev/null
+++ b/include/vdso/math64.h
@@ -0,0 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __VDSO_MATH64_H
+#define __VDSO_MATH64_H
+
+static __always_inline u32
+__iter_div_u64_rem(u64 dividend, u32 divisor, u64 *remainder)
+{
+ u32 ret = 0;
+
+ while (dividend >= divisor) {
+ /* The following asm() prevents the compiler from
+ optimising this loop into a modulo operation. */
+ asm("" : "+rm"(dividend));
+
+ dividend -= divisor;
+ ret++;
+ }
+
+ *remainder = dividend;
+
+ return ret;
+}
+
+#endif /* __VDSO_MATH64_H */

[Vincenzo Frascino]

The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.

Split time.h into linux and common headers to make the latter suitable
for inclusion in the vDSO library.

Signed-off-by: Vincenzo Frascino <***@arm.com>
---
include/linux/time.h | 5 +----
include/vdso/time.h | 12 ++++++++++++
2 files changed, 13 insertions(+), 4 deletions(-)
create mode 100644 include/vdso/time.h

diff --git a/include/linux/time.h b/include/linux/time.h
index 8ef5e5cc9f57..4c325bf44ce0 100644
--- a/include/linux/time.h
+++ b/include/linux/time.h
@@ -111,9 +111,6 @@ static inline bool itimerspec64_valid(const struct itimerspec64 *its)
*/
#define time_between32(t, l, h) ((u32)(h) - (u32)(l) >= (u32)(t) - (u32)(l))

-struct timens_offset {
- s64 sec;
- u64 nsec;
-};
+# include <vdso/time.h>

#endif
diff --git a/include/vdso/time.h b/include/vdso/time.h
new file mode 100644
index 000000000000..739f53cd2949
--- /dev/null
+++ b/include/vdso/time.h
@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __VDSO_TIME_H
+#define __VDSO_TIME_H
+
+#include <uapi/linux/types.h>
+
+struct timens_offset {
+ s64 sec;
+ u64 nsec;
+};
+
+#endif /* __VDSO_TIME_H */

[Vincenzo Frascino]

The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.

Split time32.h into linux and common headers to make the latter suitable
for inclusion in the vDSO library.

Signed-off-by: Vincenzo Frascino <***@arm.com>
---
include/linux/time32.h | 14 ++------------
include/vdso/time32.h | 17 +++++++++++++++++
2 files changed, 19 insertions(+), 12 deletions(-)
create mode 100644 include/vdso/time32.h

diff --git a/include/linux/time32.h b/include/linux/time32.h
index cad4c3186002..0933f28214c0 100644
--- a/include/linux/time32.h
+++ b/include/linux/time32.h
@@ -12,19 +12,9 @@
#include <linux/time64.h>
#include <linux/timex.h>

-#define TIME_T_MAX (__kernel_old_time_t)((1UL << ((sizeof(__kernel_old_time_t) << 3) - 1)) - 1)
-
-typedef s32 old_time32_t;
-
-struct old_timespec32 {
- old_time32_t tv_sec;
- s32 tv_nsec;
-};
+#include <vdso/time32.h>

-struct old_timeval32 {
- old_time32_t tv_sec;
- s32 tv_usec;
-};
+#define TIME_T_MAX (__kernel_old_time_t)((1UL << ((sizeof(__kernel_old_time_t) << 3) - 1)) - 1)

struct old_itimerspec32 {
struct old_timespec32 it_interval;
diff --git a/include/vdso/time32.h b/include/vdso/time32.h
new file mode 100644
index 000000000000..fdf56f932f67
--- /dev/null
+++ b/include/vdso/time32.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __VDSO_TIME32_H
+#define __VDSO_TIME32_H
+
+typedef s32 old_time32_t;
+
+struct old_timespec32 {
+ old_time32_t tv_sec;
+ s32 tv_nsec;
+};
+
+struct old_timeval32 {
+ old_time32_t tv_sec;
+ s32 tv_usec;
+};
+
+#endif /* __VDSO_TIME32_H */

[Vincenzo Frascino]

The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.

Split time64.h into linux and common headers to make the latter suitable
for inclusion in the vDSO library.

Signed-off-by: Vincenzo Frascino <***@arm.com>
---
include/linux/time64.h | 10 +---------
include/vdso/time64.h | 14 ++++++++++++++
2 files changed, 15 insertions(+), 9 deletions(-)
create mode 100644 include/vdso/time64.h

diff --git a/include/linux/time64.h b/include/linux/time64.h
index 19125489ae94..c9dcb3e5781f 100644
--- a/include/linux/time64.h
+++ b/include/linux/time64.h
@@ -3,6 +3,7 @@
#define _LINUX_TIME64_H

#include <linux/math64.h>
+#include <vdso/time64.h>

typedef __s64 time64_t;
typedef __u64 timeu64_t;
@@ -19,15 +20,6 @@ struct itimerspec64 {
struct timespec64 it_value;
};

-/* Parameters used to convert the timespec values: */
-#define MSEC_PER_SEC 1000L
-#define USEC_PER_MSEC 1000L
-#define NSEC_PER_USEC 1000L
-#define NSEC_PER_MSEC 1000000L
-#define USEC_PER_SEC 1000000L
-#define NSEC_PER_SEC 1000000000L
-#define FSEC_PER_SEC 1000000000000000LL
-
/* Located here for timespec[64]_valid_strict */
#define TIME64_MAX ((s64)~((u64)1 << 63))
#define TIME64_MIN (-TIME64_MAX - 1)
diff --git a/include/vdso/time64.h b/include/vdso/time64.h
new file mode 100644
index 000000000000..9d43c3f5e89d
--- /dev/null
+++ b/include/vdso/time64.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __VDSO_TIME64_H
+#define __VDSO_TIME64_H
+
+/* Parameters used to convert the timespec values: */
+#define MSEC_PER_SEC 1000L
+#define USEC_PER_MSEC 1000L
+#define NSEC_PER_USEC 1000L
+#define NSEC_PER_MSEC 1000000L
+#define USEC_PER_SEC 1000000L
+#define NSEC_PER_SEC 1000000000L
+#define FSEC_PER_SEC 1000000000000000LL
+
+#endif /* __VDSO_TIME64_H */

[Vincenzo Frascino]

The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.

Split jiffies.h into linux and common headers to make the latter suitable
for inclusion in the vDSO library.

Signed-off-by: Vincenzo Frascino <***@arm.com>
---
include/linux/jiffies.h | 4 +---
include/vdso/jiffies.h | 11 +++++++++++
2 files changed, 12 insertions(+), 3 deletions(-)
create mode 100644 include/vdso/jiffies.h

diff --git a/include/linux/jiffies.h b/include/linux/jiffies.h
index e3279ef24d28..fed6ba96c527 100644
--- a/include/linux/jiffies.h
+++ b/include/linux/jiffies.h
@@ -8,6 +8,7 @@
#include <linux/types.h>
#include <linux/time.h>
#include <linux/timex.h>
+#include <vdso/jiffies.h>
#include <asm/param.h> /* for HZ */
#include <generated/timeconst.h>

@@ -59,9 +60,6 @@

extern int register_refined_jiffies(long clock_tick_rate);

-/* TICK_NSEC is the time between ticks in nsec assuming SHIFTED_HZ */
-#define TICK_NSEC ((NSEC_PER_SEC+HZ/2)/HZ)
-
/* TICK_USEC is the time between ticks in usec assuming SHIFTED_HZ */
#define TICK_USEC ((USEC_PER_SEC + HZ/2) / HZ)

diff --git a/include/vdso/jiffies.h b/include/vdso/jiffies.h
new file mode 100644
index 000000000000..2f9d596c8b29
--- /dev/null
+++ b/include/vdso/jiffies.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __VDSO_JIFFIES_H
+#define __VDSO_JIFFIES_H
+
+#include <asm/param.h> /* for HZ */
+#include <vdso/time64.h>
+
+/* TICK_NSEC is the time between ticks in nsec assuming SHIFTED_HZ */
+#define TICK_NSEC ((NSEC_PER_SEC+HZ/2)/HZ)
+
+#endif /* __VDSO_JIFFIES_H */

[Vincenzo Frascino]

The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.

Split ktime.h into linux and common headers to make the latter suitable
for inclusion in the vDSO library.

Signed-off-by: Vincenzo Frascino <***@arm.com>
---
include/linux/ktime.h | 9 +--------
include/vdso/ktime.h | 16 ++++++++++++++++
2 files changed, 17 insertions(+), 8 deletions(-)
create mode 100644 include/vdso/ktime.h

diff --git a/include/linux/ktime.h b/include/linux/ktime.h
index b2bb44f87f5a..1fcfce97a020 100644
--- a/include/linux/ktime.h
+++ b/include/linux/ktime.h
@@ -253,14 +253,7 @@ static inline __must_check bool ktime_to_timespec64_cond(const ktime_t kt,
}
}

-/*
- * The resolution of the clocks. The resolution value is returned in
- * the clock_getres() system call to give application programmers an
- * idea of the (in)accuracy of timers. Timer values are rounded up to
- * this resolution values.
- */
-#define LOW_RES_NSEC TICK_NSEC
-#define KTIME_LOW_RES (LOW_RES_NSEC)
+#include <vdso/ktime.h>

static inline ktime_t ns_to_ktime(u64 ns)
{
diff --git a/include/vdso/ktime.h b/include/vdso/ktime.h
new file mode 100644
index 000000000000..a0fd07239e0e
--- /dev/null
+++ b/include/vdso/ktime.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __VDSO_KTIME_H
+#define __VDSO_KTIME_H
+
+#include <vdso/jiffies.h>
+
+/*
+ * The resolution of the clocks. The resolution value is returned in
+ * the clock_getres() system call to give application programmers an
+ * idea of the (in)accuracy of timers. Timer values are rounded up to
+ * this resolution values.
+ */
+#define LOW_RES_NSEC TICK_NSEC
+#define KTIME_LOW_RES (LOW_RES_NSEC)
+
+#endif /* __VDSO_KTIME_H */

[Vincenzo Frascino]

The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.

Introduce processor.h to contain all the processor specific functions
that are suitable for vDSO inclusion.

Signed-off-by: Vincenzo Frascino <***@arm.com>
---
include/vdso/processor.h | 14 ++++++++++++++
1 file changed, 14 insertions(+)
create mode 100644 include/vdso/processor.h

diff --git a/include/vdso/processor.h b/include/vdso/processor.h
new file mode 100644
index 000000000000..fbe8265ea3c4
--- /dev/null
+++ b/include/vdso/processor.h
@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2020 ARM Ltd.
+ */
+#ifndef __VDSO_PROCESSOR_H
+#define __VDSO_PROCESSOR_H
+
+#ifndef __ASSEMBLY__
+
+#include <asm/vdso/processor.h>
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* __VDSO_PROCESSOR_H */

[Vincenzo Frascino]

In the process of creating the source file of a module modpost injects a
set of includes that are not required if the compilation unit is
statically built into the kernel.

The order of inclusion of the headers can cause redefinition problems
(e.g.):

In file included from include/linux/elf.h:5:0,
from include/linux/module.h:18,

arch/parisc/include/asm/elf.h:324:0: warning: "ELF_OSABI" redefined

#define ELF_OSABI ELFOSABI_LINUX

In file included from include/linux/elfnote.h:62:0,
from include/linux/build-salt.h:4,
from crypto/arc4.mod.c:1:
include/uapi/linux/elf.h:363:0: note: this is the location of
the previous definition
#define ELF_OSABI ELFOSABI_NONE

The issue was exposed during the development of the series [1].

[1] https://lore.kernel.org/lkml/20200306133242.26279-1-***@arm.com/

Reported-by: kbuild test robot <***@intel.com>
Cc: Masahiro Yamada <***@kernel.org>
Cc: Michal Marek <***@markovi.net>
Signed-off-by: Vincenzo Frascino <***@arm.com>
---
scripts/mod/modpost.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
index 7edfdb2f4497..0f354b1ee2aa 100644
--- a/scripts/mod/modpost.c
+++ b/scripts/mod/modpost.c
@@ -2251,8 +2251,12 @@ static int check_modname_len(struct module *mod)
**/
static void add_header(struct buffer *b, struct module *mod)
{
- buf_printf(b, "#include <linux/build-salt.h>\n");
buf_printf(b, "#include <linux/module.h>\n");
+ /*
+ * Include build-salt.h after module.h in order to
+ * inherit the definitions.
+ */
+ buf_printf(b, "#include <linux/build-salt.h>\n");
buf_printf(b, "#include <linux/vermagic.h>\n");
buf_printf(b, "#include <linux/compiler.h>\n");
buf_printf(b, "\n");

[Vincenzo Frascino]

The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.

Replace linux/elf.h with UAPI equivalent in elfnote.h to make the header
suitable for vDSO inclusion.

Signed-off-by: Vincenzo Frascino <***@arm.com>
---
include/linux/elfnote.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/elfnote.h b/include/linux/elfnote.h
index f236f5b931b2..594d4e78654f 100644
--- a/include/linux/elfnote.h
+++ b/include/linux/elfnote.h
@@ -59,7 +59,7 @@
ELFNOTE_END

#else /* !__ASSEMBLER__ */
-#include <linux/elf.h>
+#include <uapi/linux/elf.h>
/*
* Use an anonymous structure which matches the shape of
* Elf{32,64}_Nhdr, but includes the name and desc data. The size and

[Vincenzo Frascino]

The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.

Introduce asm/vdso/processor.h to contain all the arm64 specific
functions that are suitable for vDSO inclusion.

Cc: Catalin Marinas <***@arm.com>
Cc: Will Deacon <***@kernel.org>
Signed-off-by: Vincenzo Frascino <***@arm.com>
---
arch/arm64/include/asm/processor.h | 7 ++-----
arch/arm64/include/asm/vdso/processor.h | 17 +++++++++++++++++
2 files changed, 19 insertions(+), 5 deletions(-)
create mode 100644 arch/arm64/include/asm/vdso/processor.h

diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
index 5ba63204d078..e51ef2dc5749 100644
--- a/arch/arm64/include/asm/processor.h
+++ b/arch/arm64/include/asm/processor.h
@@ -28,6 +28,8 @@
#include <linux/string.h>
#include <linux/thread_info.h>

+#include <vdso/processor.h>
+
#include <asm/alternative.h>
#include <asm/cpufeature.h>
#include <asm/hw_breakpoint.h>
@@ -256,11 +258,6 @@ extern void release_thread(struct task_struct *);

unsigned long get_wchan(struct task_struct *p);

-static inline void cpu_relax(void)
-{
- asm volatile("yield" ::: "memory");
-}
-
/* Thread switching */
extern struct task_struct *cpu_switch_to(struct task_struct *prev,
struct task_struct *next);
diff --git a/arch/arm64/include/asm/vdso/processor.h b/arch/arm64/include/asm/vdso/processor.h
new file mode 100644
index 000000000000..ff830b766ad2
--- /dev/null
+++ b/arch/arm64/include/asm/vdso/processor.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2020 ARM Ltd.
+ */
+#ifndef __ASM_VDSO_PROCESSOR_H
+#define __ASM_VDSO_PROCESSOR_H
+
+#ifndef __ASSEMBLY__
+
+static inline void cpu_relax(void)
+{
+ asm volatile("yield" ::: "memory");
+}
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* __ASM_VDSO_PROCESSOR_H */

[Catalin Marinas]

Post by Vincenzo Frascino
The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.
Introduce asm/vdso/processor.h to contain all the arm64 specific
functions that are suitable for vDSO inclusion.

This patch looks fine, though it depends on the previous discussion on
compat ABI compatibility.

Acked-by: Catalin Marinas <***@arm.com>

[Vincenzo Frascino]

The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.

Refactor the vdso implementation to include common headers.

Cc: Catalin Marinas <***@arm.com>
Cc: Will Deacon <***@kernel.org>
Acked-by: Catalin Marinas <***@arm.com>
Signed-off-by: Vincenzo Frascino <***@arm.com>
---
arch/arm64/include/asm/vdso/gettimeofday.h | 1 -
arch/arm64/kernel/vdso/vgettimeofday.c | 2 --
2 files changed, 3 deletions(-)

diff --git a/arch/arm64/include/asm/vdso/gettimeofday.h b/arch/arm64/include/asm/vdso/gettimeofday.h
index 5a534432aa5d..afba6ba332f8 100644
--- a/arch/arm64/include/asm/vdso/gettimeofday.h
+++ b/arch/arm64/include/asm/vdso/gettimeofday.h
@@ -8,7 +8,6 @@
#ifndef __ASSEMBLY__

#include <asm/unistd.h>
-#include <uapi/linux/time.h>

#define VDSO_HAS_CLOCK_GETRES 1

diff --git a/arch/arm64/kernel/vdso/vgettimeofday.c b/arch/arm64/kernel/vdso/vgettimeofday.c
index 747635501a14..4236cf34d7d9 100644
--- a/arch/arm64/kernel/vdso/vgettimeofday.c
+++ b/arch/arm64/kernel/vdso/vgettimeofday.c
@@ -5,8 +5,6 @@
* Copyright (C) 2018 ARM Limited
*
*/
-#include <linux/time.h>
-#include <linux/types.h>

int __kernel_clock_gettime(clockid_t clock,
struct __kernel_timespec *ts)

[Vincenzo Frascino]

The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.

Refactor the vdso32 implementation to include common headers.

Cc: Catalin Marinas <***@arm.com>
Cc: Will Deacon <***@kernel.org>
Acked-by: Catalin Marinas <***@arm.com>
Signed-off-by: Vincenzo Frascino <***@arm.com>
---
arch/arm64/include/asm/vdso/compat_gettimeofday.h | 2 +-
arch/arm64/kernel/vdso32/vgettimeofday.c | 3 ---
2 files changed, 1 insertion(+), 4 deletions(-)

diff --git a/arch/arm64/include/asm/vdso/compat_gettimeofday.h b/arch/arm64/include/asm/vdso/compat_gettimeofday.h
index 81b0c394f1d8..8d8d1c006a68 100644
--- a/arch/arm64/include/asm/vdso/compat_gettimeofday.h
+++ b/arch/arm64/include/asm/vdso/compat_gettimeofday.h
@@ -8,7 +8,7 @@
#ifndef __ASSEMBLY__

#include <asm/unistd.h>
-#include <uapi/linux/time.h>
+#include <asm/errno.h>

#include <asm/vdso/compat_barrier.h>

diff --git a/arch/arm64/kernel/vdso32/vgettimeofday.c b/arch/arm64/kernel/vdso32/vgettimeofday.c
index 91138077b073..54fefacb1637 100644
--- a/arch/arm64/kernel/vdso32/vgettimeofday.c
+++ b/arch/arm64/kernel/vdso32/vgettimeofday.c
@@ -5,9 +5,6 @@
* Copyright (C) 2018 ARM Limited
*
*/
-#include <linux/time.h>
-#include <linux/types.h>
-
#define VALID_CLOCK_ID(x) \
((x >= 0) && (x < VDSO_BASES))

[Vincenzo Frascino]

For ABI compatibility with arm32, the compat vDSO layer on arm64 needs
to return -EINVAL when UINTPTR_MAX is passed as argument to the
clock_get* functions.

Replace TASK_SIZE_32 with a more semantically correct formula that checks
for wrapping around 0.

Note: This will allow to not define TASK_SIZE_32 for the vdso headers in a
future patch that will introduce asm/vdso/processor.h on arm64.

Cc: Catalin Marinas <***@arm.com>
Cc: Will Deacon <***@kernel.org>
Signed-off-by: Vincenzo Frascino <***@arm.com>
---
arch/arm64/kernel/vdso32/vgettimeofday.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/kernel/vdso32/vgettimeofday.c b/arch/arm64/kernel/vdso32/vgettimeofday.c
index 54fc1c2ce93f..91138077b073 100644
--- a/arch/arm64/kernel/vdso32/vgettimeofday.c
+++ b/arch/arm64/kernel/vdso32/vgettimeofday.c
@@ -8,11 +8,14 @@
#include <linux/time.h>
#include <linux/types.h>

+#define VALID_CLOCK_ID(x) \
+ ((x >= 0) && (x < VDSO_BASES))
+
int __vdso_clock_gettime(clockid_t clock,
struct old_timespec32 *ts)
{
/* The checks below are required for ABI consistency with arm */
- if ((u32)ts >= TASK_SIZE_32)
+ if ((u32)ts > UINTPTR_MAX - sizeof(*ts) + 1)
return -EFAULT;

return __cvdso_clock_gettime32(clock, ts);
@@ -22,7 +25,7 @@ int __vdso_clock_gettime64(clockid_t clock,
struct __kernel_timespec *ts)
{
/* The checks below are required for ABI consistency with arm */
- if ((u32)ts >= TASK_SIZE_32)
+ if ((u32)ts > UINTPTR_MAX - sizeof(*ts) + 1)
return -EFAULT;

return __cvdso_clock_gettime(clock, ts);
@@ -38,9 +41,12 @@ int __vdso_clock_getres(clockid_t clock_id,
struct old_timespec32 *res)
{
/* The checks below are required for ABI consistency with arm */
- if ((u32)res >= TASK_SIZE_32)
+ if ((u32)res > UINTPTR_MAX - sizeof(res) + 1)
return -EFAULT;

+ if (!VALID_CLOCK_ID(clock_id) && res == NULL)
+ return -EINVAL;
+
return __cvdso_clock_getres_time32(clock_id, res);
}

[Catalin Marinas]

Post by Vincenzo Frascino
diff --git a/arch/arm64/kernel/vdso32/vgettimeofday.c b/arch/arm64/kernel/vdso32/vgettimeofday.c
index 54fc1c2ce93f..91138077b073 100644
--- a/arch/arm64/kernel/vdso32/vgettimeofday.c
+++ b/arch/arm64/kernel/vdso32/vgettimeofday.c
@@ -8,11 +8,14 @@
#include <linux/time.h>
#include <linux/types.h>
+#define VALID_CLOCK_ID(x) \
+ ((x >= 0) && (x < VDSO_BASES))
+
int __vdso_clock_gettime(clockid_t clock,
struct old_timespec32 *ts)
{
/* The checks below are required for ABI consistency with arm */
- if ((u32)ts >= TASK_SIZE_32)
+ if ((u32)ts > UINTPTR_MAX - sizeof(*ts) + 1)
return -EFAULT;
return __cvdso_clock_gettime32(clock, ts);

I probably miss something but I can't find the TASK_SIZE check in the
arch/arm/vdso/vgettimeofday.c code. Is this done elsewhere?

Post by Vincenzo Frascino
@@ -22,7 +25,7 @@ int __vdso_clock_gettime64(clockid_t clock,
struct __kernel_timespec *ts)
{
/* The checks below are required for ABI consistency with arm */
- if ((u32)ts >= TASK_SIZE_32)
+ if ((u32)ts > UINTPTR_MAX - sizeof(*ts) + 1)
return -EFAULT;
return __cvdso_clock_gettime(clock, ts);
@@ -38,9 +41,12 @@ int __vdso_clock_getres(clockid_t clock_id,
struct old_timespec32 *res)
{
/* The checks below are required for ABI consistency with arm */
- if ((u32)res >= TASK_SIZE_32)
+ if ((u32)res > UINTPTR_MAX - sizeof(res) + 1)
return -EFAULT;
+ if (!VALID_CLOCK_ID(clock_id) && res == NULL)
+ return -EINVAL;

This last check needs an explanation. If the clock_id is invalid but res
is not NULL, we allow it. I don't see where the compatibility issue is,
arm32 doesn't have such check.

[Vincenzo Frascino]

Hi Catalin,

Post by Catalin Marinas

Post by Vincenzo Frascino
diff --git a/arch/arm64/kernel/vdso32/vgettimeofday.c b/arch/arm64/kernel/vdso32/vgettimeofday.c
index 54fc1c2ce93f..91138077b073 100644
--- a/arch/arm64/kernel/vdso32/vgettimeofday.c
+++ b/arch/arm64/kernel/vdso32/vgettimeofday.c
@@ -8,11 +8,14 @@
#include <linux/time.h>
#include <linux/types.h>
+#define VALID_CLOCK_ID(x) \
+ ((x >= 0) && (x < VDSO_BASES))
+
int __vdso_clock_gettime(clockid_t clock,
struct old_timespec32 *ts)
{
/* The checks below are required for ABI consistency with arm */
- if ((u32)ts >= TASK_SIZE_32)
+ if ((u32)ts > UINTPTR_MAX - sizeof(*ts) + 1)
return -EFAULT;
return __cvdso_clock_gettime32(clock, ts);

I probably miss something but I can't find the TASK_SIZE check in the
arch/arm/vdso/vgettimeofday.c code. Is this done elsewhere?

Can TASK_SIZE > UINTPTR_MAX on an arm64 system?

Post by Catalin Marinas

Post by Vincenzo Frascino
@@ -22,7 +25,7 @@ int __vdso_clock_gettime64(clockid_t clock,
struct __kernel_timespec *ts)
{
/* The checks below are required for ABI consistency with arm */
- if ((u32)ts >= TASK_SIZE_32)
+ if ((u32)ts > UINTPTR_MAX - sizeof(*ts) + 1)
return -EFAULT;
return __cvdso_clock_gettime(clock, ts);
@@ -38,9 +41,12 @@ int __vdso_clock_getres(clockid_t clock_id,
struct old_timespec32 *res)
{
/* The checks below are required for ABI consistency with arm */
- if ((u32)res >= TASK_SIZE_32)
+ if ((u32)res > UINTPTR_MAX - sizeof(res) + 1)
return -EFAULT;
+ if (!VALID_CLOCK_ID(clock_id) && res == NULL)
+ return -EINVAL;

This last check needs an explanation. If the clock_id is invalid but res
is not NULL, we allow it. I don't see where the compatibility issue is,
arm32 doesn't have such check.

The case that you are describing has to return -EPERM per ABI spec. This case
has to return -EINVAL.

The first case is taken care from the generic code. But if we don't do this
check before on arm64 compat we end up returning the wrong error code.

For the non compat case the same is taken care from the syscall fallback [1].

[1] lib/vdso/gettimeofday.c

[Catalin Marinas]

Post by Vincenzo Frascino

Post by Catalin Marinas

Post by Vincenzo Frascino
diff --git a/arch/arm64/kernel/vdso32/vgettimeofday.c b/arch/arm64/kernel/vdso32/vgettimeofday.c
index 54fc1c2ce93f..91138077b073 100644
--- a/arch/arm64/kernel/vdso32/vgettimeofday.c
+++ b/arch/arm64/kernel/vdso32/vgettimeofday.c
@@ -8,11 +8,14 @@
#include <linux/time.h>
#include <linux/types.h>
+#define VALID_CLOCK_ID(x) \
+ ((x >= 0) && (x < VDSO_BASES))
+
int __vdso_clock_gettime(clockid_t clock,
struct old_timespec32 *ts)
{
/* The checks below are required for ABI consistency with arm */
- if ((u32)ts >= TASK_SIZE_32)
+ if ((u32)ts > UINTPTR_MAX - sizeof(*ts) + 1)
return -EFAULT;
return __cvdso_clock_gettime32(clock, ts);

I probably miss something but I can't find the TASK_SIZE check in the
arch/arm/vdso/vgettimeofday.c code. Is this done elsewhere?

Can TASK_SIZE > UINTPTR_MAX on an arm64 system?

TASK_SIZE yes on arm64 but not TASK_SIZE_32. I was asking about the
arm32 check where TASK_SIZE < UINTPTR_MAX. How does the vdsotest return
-EFAULT on arm32? Which code path causes this in the user vdso code?

My guess is that on arm32 it only fails with -EFAULT in the syscall
fallback path since a copy_to_user() would fail the access_ok() check.
Does it always take the fallback path if ts > TASK_SIZE?

On arm64, while we have a similar access_ok() check, USER_DS is (1 <<
VA_BITS) even for compat tasks (52-bit maximum), so it doesn't detect
the end of the user address space for 32-bit tasks.

Is this an issue for other syscalls expecting EFAULT at UINTPTR_MAX and
instead getting a signal? The vdsotest seems to be the only one assuming
this. I don't have a simple solution here since USER_DS currently needs
to be a constant (used in entry.S).

I could as well argue that this is not a valid ABI test, no real-world
program relying on this behaviour ;).

Post by Vincenzo Frascino

Post by Catalin Marinas

Post by Vincenzo Frascino
@@ -22,7 +25,7 @@ int __vdso_clock_gettime64(clockid_t clock,
struct __kernel_timespec *ts)
{
/* The checks below are required for ABI consistency with arm */
- if ((u32)ts >= TASK_SIZE_32)
+ if ((u32)ts > UINTPTR_MAX - sizeof(*ts) + 1)
return -EFAULT;
return __cvdso_clock_gettime(clock, ts);
@@ -38,9 +41,12 @@ int __vdso_clock_getres(clockid_t clock_id,
struct old_timespec32 *res)
{
/* The checks below are required for ABI consistency with arm */
- if ((u32)res >= TASK_SIZE_32)
+ if ((u32)res > UINTPTR_MAX - sizeof(res) + 1)
return -EFAULT;
+ if (!VALID_CLOCK_ID(clock_id) && res == NULL)
+ return -EINVAL;

This last check needs an explanation. If the clock_id is invalid but res
is not NULL, we allow it. I don't see where the compatibility issue is,
arm32 doesn't have such check.

The case that you are describing has to return -EPERM per ABI spec. This case
has to return -EINVAL.
The first case is taken care from the generic code. But if we don't do this
check before on arm64 compat we end up returning the wrong error code.

I guess I have the same question as above. Where does the arm32 code
return -EINVAL for that case? Did it work correctly before you removed
the TASK_SIZE_32 check?

Sorry, just trying to figure out where the compatibility aspect is and
that we don't add some artificial checks only to satisfy a vdsotest case
that may or may not have relevance to any other user program.

[Vincenzo Frascino]

Hi Catalin,
[...]

Post by Catalin Marinas

Post by Vincenzo Frascino
Can TASK_SIZE > UINTPTR_MAX on an arm64 system?

TASK_SIZE yes on arm64 but not TASK_SIZE_32. I was asking about the
arm32 check where TASK_SIZE < UINTPTR_MAX. How does the vdsotest return
-EFAULT on arm32? Which code path causes this in the user vdso code?

Sorry I got confused because you referred to arch/arm/vdso/vgettimeofday.c which
is the arm64 implementation, not the compat one :)

In the case of arm32 everything is handled via syscall fallback.

Post by Catalin Marinas
My guess is that on arm32 it only fails with -EFAULT in the syscall
fallback path since a copy_to_user() would fail the access_ok() check.
Does it always take the fallback path if ts > TASK_SIZE?

Correct, it goes via fallback. The return codes for these syscalls are specified
by the ABI [1]. Then I agree with you the way on which arm32 achieves it should
be via access_ok() check.

Post by Catalin Marinas
On arm64, while we have a similar access_ok() check, USER_DS is (1 <<
VA_BITS) even for compat tasks (52-bit maximum), so it doesn't detect
the end of the user address space for 32-bit tasks.

I agree on this as well, if you remember we discussed it in past.

Post by Catalin Marinas
Is this an issue for other syscalls expecting EFAULT at UINTPTR_MAX and
instead getting a signal? The vdsotest seems to be the only one assuming
this. I don't have a simple solution here since USER_DS currently needs
to be a constant (used in entry.S).
I could as well argue that this is not a valid ABI test, no real-world
program relying on this behaviour ;).

Ok, but I could argue that unless you manage to prove to me that there is no
software out there relying on this behavior, I guess that the safest way to go
is to have a check here ;)

More than that, being a simple check, it has no performance impact.

[...]

Post by Catalin Marinas

Post by Vincenzo Frascino

Post by Catalin Marinas
This last check needs an explanation. If the clock_id is invalid but res
is not NULL, we allow it. I don't see where the compatibility issue is,
arm32 doesn't have such check.

The case that you are describing has to return -EPERM per ABI spec. This case
has to return -EINVAL.
The first case is taken care from the generic code. But if we don't do this
check before on arm64 compat we end up returning the wrong error code.

I guess I have the same question as above. Where does the arm32 code
return -EINVAL for that case? Did it work correctly before you removed
the TASK_SIZE_32 check?

I repeated the test and seems that it was failing even before I removed
TASK_SIZE_32. For reasons I can't explain I did not catch it before.

The getres syscall should return -EINVAL in the cases specified in [1].

Post by Catalin Marinas
Sorry, just trying to figure out where the compatibility aspect is and
that we don't add some artificial checks only to satisfy a vdsotest case
that may or may not have relevance to any other user program.

No issue Catalin. I understand the implications of the change that I am
proposing with this series and I am the first one who wants to get it right.

Said that vdsotest follows "pedantically" the ABI spec and I chose it at the
beginning of this journey to have as less surprises as I could in the long run.

[1] http://man7.org/linux/man-pages/man2/clock_getres.2.html

[Vincenzo Frascino]

Post by Vincenzo Frascino
Hi Catalin,
[...]

Post by Catalin Marinas

Post by Vincenzo Frascino
Can TASK_SIZE > UINTPTR_MAX on an arm64 system?

TASK_SIZE yes on arm64 but not TASK_SIZE_32. I was asking about the
arm32 check where TASK_SIZE < UINTPTR_MAX. How does the vdsotest return
-EFAULT on arm32? Which code path causes this in the user vdso code?

Sorry I got confused because you referred to arch/arm/vdso/vgettimeofday.c which
is the arm64 implementation, not the compat one :)

I stand corrected arch/*arm*/vdso/vgettimeofday.c is definitely the arm32
implemetation... I got completely confused here :)

[Catalin Marinas]

Post by Vincenzo Frascino

Post by Catalin Marinas

Post by Vincenzo Frascino
Can TASK_SIZE > UINTPTR_MAX on an arm64 system?

TASK_SIZE yes on arm64 but not TASK_SIZE_32. I was asking about the
arm32 check where TASK_SIZE < UINTPTR_MAX. How does the vdsotest return
-EFAULT on arm32? Which code path causes this in the user vdso code?

Sorry I got confused because you referred to arch/arm/vdso/vgettimeofday.c which
is the arm64 implementation, not the compat one :)

You figured out (in your subsequent reply) that I was indeed talking
about arm32 ;).

Post by Vincenzo Frascino
In the case of arm32 everything is handled via syscall fallback.

So clock_gettime() on arm32 always falls back to the syscall?

Post by Vincenzo Frascino

Post by Catalin Marinas
My guess is that on arm32 it only fails with -EFAULT in the syscall
fallback path since a copy_to_user() would fail the access_ok() check.
Does it always take the fallback path if ts > TASK_SIZE?

Correct, it goes via fallback. The return codes for these syscalls are specified
by the ABI [1]. Then I agree with you the way on which arm32 achieves it should
be via access_ok() check.

"it should be" or "it is" on arm32?

If, on arm32, clock_gettime() is (would be?) handled in the vdso
entirely, who checks for the pointer outside the accessible address
space (as per the clock_gettime man page)?

I'm fine with such check as long as it is consistent across arm32 and
arm64 compat. Or even on arm64 native between syscall fallback and vdso
execution. I haven't figured out yet whether this is the case.

Post by Vincenzo Frascino

Post by Catalin Marinas

Post by Vincenzo Frascino

Post by Catalin Marinas
This last check needs an explanation. If the clock_id is invalid but res
is not NULL, we allow it. I don't see where the compatibility issue is,
arm32 doesn't have such check.

The case that you are describing has to return -EPERM per ABI spec. This case
has to return -EINVAL.
The first case is taken care from the generic code. But if we don't do this
check before on arm64 compat we end up returning the wrong error code.

I guess I have the same question as above. Where does the arm32 code
return -EINVAL for that case? Did it work correctly before you removed
the TASK_SIZE_32 check?

I repeated the test and seems that it was failing even before I removed
TASK_SIZE_32. For reasons I can't explain I did not catch it before.
The getres syscall should return -EINVAL in the cases specified in [1].

It states 'clk_id specified is not supported on this system'. Fair
enough but it doesn't say that it returns -EINVAL only if res == NULL.
You also don't explain why __cvdso_clock_getres_time32() doesn't already
detect an invalid clk_id on arm64 compat (but does it on arm32).

[Vincenzo Frascino]

Enable x86 to use only the common headers in the implementation
of the vDSO library.

Cc: Thomas Gleixner <***@linutronix.de>
Cc: Andy Lutomirski <***@kernel.org>
Cc: Ingo Molnar <***@redhat.com>
Cc: Borislav Petkov <***@alien8.de>
Signed-off-by: Vincenzo Frascino <***@arm.com>
---
arch/x86/include/asm/processor.h | 12 +-----------
arch/x86/include/asm/vdso/processor.h | 23 +++++++++++++++++++++++
2 files changed, 24 insertions(+), 11 deletions(-)
create mode 100644 arch/x86/include/asm/vdso/processor.h

diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 09705ccc393c..94789db550df 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -26,6 +26,7 @@ struct vm86;
#include <asm/fpu/types.h>
#include <asm/unwind_hints.h>
#include <asm/vmxfeatures.h>
+#include <asm/vdso/processor.h>

#include <linux/personality.h>
#include <linux/cache.h>
@@ -677,17 +678,6 @@ static inline unsigned int cpuid_edx(unsigned int op)
return edx;
}

-/* REP NOP (PAUSE) is a good thing to insert into busy-wait loops. */
-static __always_inline void rep_nop(void)
-{
- asm volatile("rep; nop" ::: "memory");
-}
-
-static __always_inline void cpu_relax(void)
-{
- rep_nop();
-}
-
/*
* This function forces the icache and prefetched instruction stream to
* catch up with reality in two very specific cases:
diff --git a/arch/x86/include/asm/vdso/processor.h b/arch/x86/include/asm/vdso/processor.h
new file mode 100644
index 000000000000..57b1a7034c64
--- /dev/null
+++ b/arch/x86/include/asm/vdso/processor.h
@@ -0,0 +1,23 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2020 ARM Ltd.
+ */
+#ifndef __ASM_VDSO_PROCESSOR_H
+#define __ASM_VDSO_PROCESSOR_H
+
+#ifndef __ASSEMBLY__
+
+/* REP NOP (PAUSE) is a good thing to insert into busy-wait loops. */
+static __always_inline void rep_nop(void)
+{
+ asm volatile("rep; nop" ::: "memory");
+}
+
+static __always_inline void cpu_relax(void)
+{
+ rep_nop();
+}
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* __ASM_VDSO_PROCESSOR_H */

[Vincenzo Frascino]

Enable arm to use only the common headers in the implementation
of the vDSO library.

Cc: Russell King <***@armlinux.org.uk>
Signed-off-by: Vincenzo Frascino <***@arm.com>
---
arch/arm/include/asm/cp15.h | 20 +------------
arch/arm/include/asm/processor.h | 11 +------
arch/arm/include/asm/vdso/cp15.h | 38 ++++++++++++++++++++++++
arch/arm/include/asm/vdso/gettimeofday.h | 4 +--
arch/arm/include/asm/vdso/processor.h | 22 ++++++++++++++
5 files changed, 64 insertions(+), 31 deletions(-)
create mode 100644 arch/arm/include/asm/vdso/cp15.h
create mode 100644 arch/arm/include/asm/vdso/processor.h

diff --git a/arch/arm/include/asm/cp15.h b/arch/arm/include/asm/cp15.h
index d2453e2d3f1f..a54230e65647 100644
--- a/arch/arm/include/asm/cp15.h
+++ b/arch/arm/include/asm/cp15.h
@@ -50,25 +50,7 @@

#ifdef CONFIG_CPU_CP15

-#define __ACCESS_CP15(CRn, Op1, CRm, Op2) \
- "mrc", "mcr", __stringify(p15, Op1, %0, CRn, CRm, Op2), u32
-#define __ACCESS_CP15_64(Op1, CRm) \
- "mrrc", "mcrr", __stringify(p15, Op1, %Q0, %R0, CRm), u64
-
-#define __read_sysreg(r, w, c, t) ({ \
- t __val; \
- asm volatile(r " " c : "=r" (__val)); \
- __val; \
-})
-#define read_sysreg(...) __read_sysreg(__VA_ARGS__)
-
-#define __write_sysreg(v, r, w, c, t) asm volatile(w " " c : : "r" ((t)(v)))
-#define write_sysreg(v, ...) __write_sysreg(v, __VA_ARGS__)
-
-#define BPIALL __ACCESS_CP15(c7, 0, c5, 6)
-#define ICIALLU __ACCESS_CP15(c7, 0, c5, 0)
-
-#define CNTVCT __ACCESS_CP15_64(1, c14)
+#include <asm/vdso/cp15.h>

extern unsigned long cr_alignment; /* defined in entry-armv.S */

diff --git a/arch/arm/include/asm/processor.h b/arch/arm/include/asm/processor.h
index 614bf829e454..b9241051e5cb 100644
--- a/arch/arm/include/asm/processor.h
+++ b/arch/arm/include/asm/processor.h
@@ -14,6 +14,7 @@
#include <asm/ptrace.h>
#include <asm/types.h>
#include <asm/unified.h>
+#include <asm/vdso/processor.h>

#ifdef __KERNEL__
#define STACK_TOP ((current->personality & ADDR_LIMIT_32BIT) ? \
@@ -85,16 +86,6 @@ extern void release_thread(struct task_struct *);

unsigned long get_wchan(struct task_struct *p);

-#if __LINUX_ARM_ARCH__ == 6 || defined(CONFIG_ARM_ERRATA_754327)
-#define cpu_relax() \
- do { \
- smp_mb(); \
- __asm__ __volatile__("nop; nop; nop; nop; nop; nop; nop; nop; nop; nop;"); \
- } while (0)
-#else
-#define cpu_relax() barrier()
-#endif
-
#define task_pt_regs(p) \
((struct pt_regs *)(THREAD_START_SP + task_stack_page(p)) - 1)

diff --git a/arch/arm/include/asm/vdso/cp15.h b/arch/arm/include/asm/vdso/cp15.h
new file mode 100644
index 000000000000..bed16fa1865e
--- /dev/null
+++ b/arch/arm/include/asm/vdso/cp15.h
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2020 ARM Ltd.
+ */
+#ifndef __ASM_VDSO_CP15_H
+#define __ASM_VDSO_CP15_H
+
+#ifndef __ASSEMBLY__
+
+#ifdef CONFIG_CPU_CP15
+
+#include <linux/stringify.h>
+
+#define __ACCESS_CP15(CRn, Op1, CRm, Op2) \
+ "mrc", "mcr", __stringify(p15, Op1, %0, CRn, CRm, Op2), u32
+#define __ACCESS_CP15_64(Op1, CRm) \
+ "mrrc", "mcrr", __stringify(p15, Op1, %Q0, %R0, CRm), u64
+
+#define __read_sysreg(r, w, c, t) ({ \
+ t __val; \
+ asm volatile(r " " c : "=r" (__val)); \
+ __val; \
+})
+#define read_sysreg(...) __read_sysreg(__VA_ARGS__)
+
+#define __write_sysreg(v, r, w, c, t) asm volatile(w " " c : : "r" ((t)(v)))
+#define write_sysreg(v, ...) __write_sysreg(v, __VA_ARGS__)
+
+#define BPIALL __ACCESS_CP15(c7, 0, c5, 6)
+#define ICIALLU __ACCESS_CP15(c7, 0, c5, 0)
+
+#define CNTVCT __ACCESS_CP15_64(1, c14)
+
+#endif /* CONFIG_CPU_CP15 */
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* __ASM_VDSO_CP15_H */
diff --git a/arch/arm/include/asm/vdso/gettimeofday.h b/arch/arm/include/asm/vdso/gettimeofday.h
index 07d791c65cf7..36dc18553ed8 100644
--- a/arch/arm/include/asm/vdso/gettimeofday.h
+++ b/arch/arm/include/asm/vdso/gettimeofday.h
@@ -7,9 +7,9 @@

#ifndef __ASSEMBLY__

-#include <asm/barrier.h>
-#include <asm/cp15.h>
+#include <asm/errno.h>
#include <asm/unistd.h>
+#include <asm/vdso/cp15.h>
#include <uapi/linux/time.h>

#define VDSO_HAS_CLOCK_GETRES 1
diff --git a/arch/arm/include/asm/vdso/processor.h b/arch/arm/include/asm/vdso/processor.h
new file mode 100644
index 000000000000..45efb3ff511c
--- /dev/null
+++ b/arch/arm/include/asm/vdso/processor.h
@@ -0,0 +1,22 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2020 ARM Ltd.
+ */
+#ifndef __ASM_VDSO_PROCESSOR_H
+#define __ASM_VDSO_PROCESSOR_H
+
+#ifndef __ASSEMBLY__
+
+#if __LINUX_ARM_ARCH__ == 6 || defined(CONFIG_ARM_ERRATA_754327)
+#define cpu_relax() \
+ do { \
+ smp_mb(); \
+ __asm__ __volatile__("nop; nop; nop; nop; nop; nop; nop; nop; nop; nop;"); \
+ } while (0)
+#else
+#define cpu_relax() barrier()
+#endif
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* __ASM_VDSO_PROCESSOR_H */

[Vincenzo Frascino]

The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To make
this possible it is necessary to isolate from the kernel headers the
common parts that are strictly necessary to build the library.

Refactor the unified vdso code to use the common headers.

Cc: Andy Lutomirski <***@kernel.org>
Cc: Thomas Gleixner <***@linutronix.de>
Signed-off-by: Vincenzo Frascino <***@arm.com>
---
include/vdso/datapage.h | 33 ++++++++++++++++++++++++++++++---
lib/vdso/gettimeofday.c | 22 ----------------------
2 files changed, 30 insertions(+), 25 deletions(-)

diff --git a/include/vdso/datapage.h b/include/vdso/datapage.h
index 30c4cb0428d1..5cbc9fcbfd45 100644
--- a/include/vdso/datapage.h
+++ b/include/vdso/datapage.h
@@ -4,9 +4,20 @@

#ifndef __ASSEMBLY__

-#include <linux/bits.h>
-#include <linux/time.h>
-#include <linux/types.h>
+#include <linux/compiler.h>
+#include <uapi/linux/time.h>
+#include <uapi/linux/types.h>
+#include <uapi/asm-generic/errno-base.h>
+
+#include <vdso/bits.h>
+#include <vdso/clocksource.h>
+#include <vdso/ktime.h>
+#include <vdso/limits.h>
+#include <vdso/math64.h>
+#include <vdso/processor.h>
+#include <vdso/time.h>
+#include <vdso/time32.h>
+#include <vdso/time64.h>

#define VDSO_BASES (CLOCK_TAI + 1)
#define VDSO_HRES (BIT(CLOCK_REALTIME) | \
@@ -99,6 +110,22 @@ struct vdso_data {
*/
extern struct vdso_data _vdso_data[CS_BASES] __attribute__((visibility("hidden")));

+/*
+ * The generic vDSO implementation requires that gettimeofday.h
+ * provides:
+ * - __arch_get_vdso_data(): to get the vdso datapage.
+ * - __arch_get_hw_counter(): to get the hw counter based on the
+ * clock_mode.
+ * - gettimeofday_fallback(): fallback for gettimeofday.
+ * - clock_gettime_fallback(): fallback for clock_gettime.
+ * - clock_getres_fallback(): fallback for clock_getres.
+ */
+#ifdef ENABLE_COMPAT_VDSO
+#include <asm/vdso/compat_gettimeofday.h>
+#else
+#include <asm/vdso/gettimeofday.h>
+#endif /* ENABLE_COMPAT_VDSO */
+
#endif /* !__ASSEMBLY__ */

#endif /* __VDSO_DATAPAGE_H */
diff --git a/lib/vdso/gettimeofday.c b/lib/vdso/gettimeofday.c
index 72d282ffd156..a2909af4b924 100644
--- a/lib/vdso/gettimeofday.c
+++ b/lib/vdso/gettimeofday.c
@@ -2,31 +2,9 @@
/*
* Generic userspace implementations of gettimeofday() and similar.
*/
-#include <linux/compiler.h>
-#include <linux/math64.h>
-#include <linux/time.h>
-#include <linux/kernel.h>
-#include <linux/hrtimer_defs.h>
-#include <linux/clocksource.h>
#include <vdso/datapage.h>
#include <vdso/helpers.h>

-/*
- * The generic vDSO implementation requires that gettimeofday.h
- * provides:
- * - __arch_get_vdso_data(): to get the vdso datapage.
- * - __arch_get_hw_counter(): to get the hw counter based on the
- * clock_mode.
- * - gettimeofday_fallback(): fallback for gettimeofday.
- * - clock_gettime_fallback(): fallback for clock_gettime.
- * - clock_getres_fallback(): fallback for clock_getres.
- */
-#ifdef ENABLE_COMPAT_VDSO
-#include <asm/vdso/compat_gettimeofday.h>
-#else
-#include <asm/vdso/gettimeofday.h>
-#endif /* ENABLE_COMPAT_VDSO */
-
#ifndef vdso_calc_delta
/*
* Default implementation which works for all sane clocksources. That

[Vincenzo Frascino]

Enable Clang Compilation for the vdso32 library.

Cc: Catalin Marinas <***@arm.com>
Cc: Will Deacon <***@kernel.org>
Reviewed-by: Nathan Chancellor <***@gmail.com>
Tested-by: Nathan Chancellor <***@gmail.com> # build
Acked-by: Catalin Marinas <***@arm.com>
Signed-off-by: Vincenzo Frascino <***@arm.com>
---
arch/arm64/kernel/vdso32/Makefile | 11 +++++++++++
1 file changed, 11 insertions(+)

diff --git a/arch/arm64/kernel/vdso32/Makefile b/arch/arm64/kernel/vdso32/Makefile
index 04df57b43cb1..3964738ebbde 100644
--- a/arch/arm64/kernel/vdso32/Makefile
+++ b/arch/arm64/kernel/vdso32/Makefile
@@ -10,7 +10,18 @@ include $(srctree)/lib/vdso/Makefile

# Same as cc-*option, but using CC_COMPAT instead of CC
ifeq ($(CONFIG_CC_IS_CLANG), y)
+COMPAT_GCC_TOOLCHAIN_DIR := $(dir $(shell which $(CROSS_COMPILE_COMPAT)elfedit))
+COMPAT_GCC_TOOLCHAIN := $(realpath $(COMPAT_GCC_TOOLCHAIN_DIR)/..)
+
+CC_COMPAT_CLANG_FLAGS := --target=$(notdir $(CROSS_COMPILE_COMPAT:%-=%))
+CC_COMPAT_CLANG_FLAGS += --prefix=$(COMPAT_GCC_TOOLCHAIN_DIR)
+CC_COMPAT_CLANG_FLAGS += -no-integrated-as -Qunused-arguments
+ifneq ($(COMPAT_GCC_TOOLCHAIN),)
+CC_COMPAT_CLANG_FLAGS += --gcc-toolchain=$(COMPAT_GCC_TOOLCHAIN)
+endif
+
CC_COMPAT ?= $(CC)
+CC_COMPAT += $(CC_COMPAT_CLANG_FLAGS)
else
CC_COMPAT ?= $(CROSS_COMPILE_COMPAT)gcc
endif

[Vincenzo Frascino]

Enable mips to use only the common headers in the implementation of
the vDSO library.

Cc: Paul Burton <***@kernel.org>
Signed-off-by: Vincenzo Frascino <***@arm.com>
---
arch/mips/include/asm/processor.h | 16 +-------------
arch/mips/include/asm/vdso/gettimeofday.h | 4 ----
arch/mips/include/asm/vdso/processor.h | 27 +++++++++++++++++++++++
3 files changed, 28 insertions(+), 19 deletions(-)
create mode 100644 arch/mips/include/asm/vdso/processor.h

diff --git a/arch/mips/include/asm/processor.h b/arch/mips/include/asm/processor.h
index 7619ad319400..4c9cc667f3ed 100644
--- a/arch/mips/include/asm/processor.h
+++ b/arch/mips/include/asm/processor.h
@@ -22,6 +22,7 @@
#include <asm/dsemul.h>
#include <asm/mipsregs.h>
#include <asm/prefetch.h>
+#include <asm/vdso/processor.h>

/*
* System setup and hardware flags..
@@ -385,21 +386,6 @@ unsigned long get_wchan(struct task_struct *p);
#define KSTK_ESP(tsk) (task_pt_regs(tsk)->regs[29])
#define KSTK_STATUS(tsk) (task_pt_regs(tsk)->cp0_status)

-#ifdef CONFIG_CPU_LOONGSON64
-/*
- * Loongson-3's SFB (Store-Fill-Buffer) may buffer writes indefinitely when a
- * tight read loop is executed, because reads take priority over writes & the
- * hardware (incorrectly) doesn't ensure that writes will eventually occur.
- *
- * Since spin loops of any kind should have a cpu_relax() in them, force an SFB
- * flush from cpu_relax() such that any pending writes will become visible as
- * expected.
- */
-#define cpu_relax() smp_mb()
-#else
-#define cpu_relax() barrier()
-#endif
-
/*
* Return_address is a replacement for __builtin_return_address(count)
* which on certain architectures cannot reasonably be implemented in GCC
diff --git a/arch/mips/include/asm/vdso/gettimeofday.h b/arch/mips/include/asm/vdso/gettimeofday.h
index 88c3de1bdf22..c63ddcaea54c 100644
--- a/arch/mips/include/asm/vdso/gettimeofday.h
+++ b/arch/mips/include/asm/vdso/gettimeofday.h
@@ -13,12 +13,8 @@

#ifndef __ASSEMBLY__

-#include <linux/compiler.h>
-#include <linux/time.h>
-
#include <asm/vdso/vdso.h>
#include <asm/clocksource.h>
-#include <asm/io.h>
#include <asm/unistd.h>
#include <asm/vdso.h>

diff --git a/arch/mips/include/asm/vdso/processor.h b/arch/mips/include/asm/vdso/processor.h
new file mode 100644
index 000000000000..511c95d735e6
--- /dev/null
+++ b/arch/mips/include/asm/vdso/processor.h
@@ -0,0 +1,27 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2020 ARM Ltd.
+ */
+#ifndef __ASM_VDSO_PROCESSOR_H
+#define __ASM_VDSO_PROCESSOR_H
+
+#ifndef __ASSEMBLY__
+
+#ifdef CONFIG_CPU_LOONGSON64
+/*
+ * Loongson-3's SFB (Store-Fill-Buffer) may buffer writes indefinitely when a
+ * tight read loop is executed, because reads take priority over writes & the
+ * hardware (incorrectly) doesn't ensure that writes will eventually occur.
+ *
+ * Since spin loops of any kind should have a cpu_relax() in them, force an SFB
+ * flush from cpu_relax() such that any pending writes will become visible as
+ * expected.
+ */
+#define cpu_relax() smp_mb()
+#else
+#define cpu_relax() barrier()
+#endif
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* __ASM_VDSO_PROCESSOR_H */