arm64: vdso32: Define BUILD_VDSO32_64 to correct prototypes

After commit 42874e4eb35b ("arch: vdso: consolidate gettime
prototypes"), there are a couple of errors when building the 32-bit
compat vDS

arm64: vdso32: Define BUILD_VDSO32_64 to correct prototypes

After commit 42874e4eb35b ("arch: vdso: consolidate gettime
prototypes"), there are a couple of errors when building the 32-bit
compat vDSO for arm64:

arch/arm64/kernel/vdso32/vgettimeofday.c:10:5: error: conflicting types for '__vdso_clock_gettime'; have 'int(clockid_t, struct old_timespec32 *)' {aka 'int(int, struct old_timespec32 *)'}
10 | int __vdso_clock_gettime(clockid_t clock,
| ^~~~~~~~~~~~~~~~~~~~
In file included from arch/arm64/kernel/vdso32/vgettimeofday.c:8:
include/vdso/gettime.h:16:5: note: previous declaration of '__vdso_clock_gettime' with type 'int(clockid_t, struct __kernel_timespec *)' {aka 'int(int, struct __kernel_timespec *)'}
16 | int __vdso_clock_gettime(clockid_t clock, struct __kernel_timespec *ts);
| ^~~~~~~~~~~~~~~~~~~~
arch/arm64/kernel/vdso32/vgettimeofday.c:28:5: error: conflicting types for '__vdso_clock_getres'; have 'int(clockid_t, struct old_timespec32 *)' {aka 'int(int, struct old_timespec32 *)'}
28 | int __vdso_clock_getres(clockid_t clock_id,
| ^~~~~~~~~~~~~~~~~~~
include/vdso/gettime.h:15:5: note: previous declaration of '__vdso_clock_getres' with type 'int(clockid_t, struct __kernel_timespec *)' {aka 'int(int, struct __kernel_timespec *)'}
15 | int __vdso_clock_getres(clockid_t clock, struct __kernel_timespec *res);
| ^~~~~~~~~~~~~~~~~~~

The type of the second parameter in __vdso_clock_getres() and
__vdso_clock_gettime() changes based on whether compiling for 32-bit vs.
64-bit, which is controlled by CONFIG_64BIT or the preprocessor macro
BUILD_VDSO32_64, which denotes a 32-bit vDSO is being built for a 64-bit
architecture. Since this situation is the latter case, define
BUILD_VDSO32_64 before the inclusion of include/vdso/gettime.h to clear
up the warning

Fixes: 42874e4eb35b ("arch: vdso: consolidate gettime prototypes")
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Closes: https://lore.kernel.org/CA+G9fYtV6X=c3JVTTAX89_=wc+uqLpzggnsbGSx-98m_5yd5yw@mail.gmail.com/
Reported-by: Mark Brown <broonie@kernel.org>
Closes: https://lore.kernel.org/ZWCRWArzbTYUjvon@finisterre.sirena.org.uk/
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

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arch: vdso: consolidate gettime prototypes

The VDSO functions are defined as globals in the kernel sources but intended
to be called from userspace, so there is no need to declare them in a kernel
s

arch: vdso: consolidate gettime prototypes

The VDSO functions are defined as globals in the kernel sources but intended
to be called from userspace, so there is no need to declare them in a kernel
side header.

Without a prototype, this now causes warnings such as

arch/mips/vdso/vgettimeofday.c:14:5: error: no previous prototype for '__vdso_clock_gettime' [-Werror=missing-prototypes]
arch/mips/vdso/vgettimeofday.c:28:5: error: no previous prototype for '__vdso_gettimeofday' [-Werror=missing-prototypes]
arch/mips/vdso/vgettimeofday.c:36:5: error: no previous prototype for '__vdso_clock_getres' [-Werror=missing-prototypes]
arch/mips/vdso/vgettimeofday.c:42:5: error: no previous prototype for '__vdso_clock_gettime64' [-Werror=missing-prototypes]
arch/sparc/vdso/vclock_gettime.c:254:1: error: no previous prototype for '__vdso_clock_gettime' [-Werror=missing-prototypes]
arch/sparc/vdso/vclock_gettime.c:282:1: error: no previous prototype for '__vdso_clock_gettime_stick' [-Werror=missing-prototypes]
arch/sparc/vdso/vclock_gettime.c:307:1: error: no previous prototype for '__vdso_gettimeofday' [-Werror=missing-prototypes]
arch/sparc/vdso/vclock_gettime.c:343:1: error: no previous prototype for '__vdso_gettimeofday_stick' [-Werror=missing-prototypes]

Most architectures have already added workarounds for these by adding
declarations somewhere, but since these are all compatible, we should
really just have one copy, with an #ifdef check for the 32-bit vs
64-bit variant and use that everywhere.

Unfortunately, the sparc an um versions are currently incompatible
since they never added support for __vdso_clock_gettime64() in 32-bit
userland. For the moment, I'm leaving this one out, as I can't
easily test it and it requires a larger rework.

Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

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arm64: vdso32: Include common headers in the vdso library

The vDSO library should only include the necessary headers required for
a userspace library (UAPI and a minimal set of kernel headers). To m

arm64: vdso32: Include common headers in the vdso library

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.

Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lkml.kernel.org/r/20200320145351.32292-22-vincenzo.frascino@arm.com

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arm64: vdso32: Code clean up

The compat vdso library had some checks that are not anymore relevant.

Remove the unused code from the compat vDSO library.

Note: This patch is preparatory for a futur

arm64: vdso32: Code clean up

The compat vdso library had some checks that are not anymore relevant.

Remove the unused code from the compat vDSO library.

Note: This patch is preparatory for a future one that will introduce
asm/vdso/processor.h on arm64.

Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/lkml/20200317122220.30393-19-vincenzo.frascino@arm.com
Link: https://lkml.kernel.org/r/20200320145351.32292-19-vincenzo.frascino@arm.com

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arm64: compat: Add vDSO

Provide the arm64 compat (AArch32) vDSO in kernel/vdso32 in a similar
way to what happens in kernel/vdso.

The compat vDSO leverages on an adaptation of the arm architecture

arm64: compat: Add vDSO

Provide the arm64 compat (AArch32) vDSO in kernel/vdso32 in a similar
way to what happens in kernel/vdso.

The compat vDSO leverages on an adaptation of the arm architecture code
with few changes:

- Use of lib/vdso for gettimeofday
- Implement a syscall based fallback
- Introduce clock_getres() for the compat library
- Implement trampolines
- Implement elf note

To build the compat vDSO a 32 bit compiler is required and needs to be
specified via CONFIG_CROSS_COMPILE_COMPAT_VDSO.

The code is not yet enabled as other prerequisites are missing.

Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Shijith Thotton <sthotton@marvell.com>
Tested-by: Andre Przywara <andre.przywara@arm.com>
Cc: linux-arch@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-mips@vger.kernel.org
Cc: linux-kselftest@vger.kernel.org
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paul.burton@mips.com>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Mark Salyzyn <salyzyn@android.com>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Huw Davies <huw@codeweavers.com>
Link: https://lkml.kernel.org/r/20190621095252.32307-11-vincenzo.frascino@arm.com

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