MIPS already uses and S390 will need the vdso data pointer in
__arch_get_hw_counter().
This works nicely as long as the architecture does not support time
namespaces in the VDSO. With time namespaces enabled the regular
accessor to the vdso data pointer __arch_get_vdso_data() will return the
namespace specific VDSO data page for tasks which are part of a
non-root time namespace. This would cause the architectures which need
the vdso data pointer in __arch_get_hw_counter() to access the wrong
vdso data page.
Add a vdso_data pointer argument to __arch_get_hw_counter() and hand it in
from the call sites in the core code. For architectures which do not need
the data pointer in their counter accessor function the compiler will just
optimize it out.
Fix up all existing architecture implementations and make MIPS utilize the
pointer instead of invoking the accessor function.
No functional change and no change in the resulting object code (except
MIPS).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/draft-87wo2ekuzn.fsf@nanos.tec.linutronix.de
The libc provides a discovery mechanism for vDSO library and its
symbols. When a symbol is not exposed by the vDSOs the libc falls back
on the system calls.
With the introduction of the unified vDSO library on mips this behavior
is not honored anymore by the kernel in the case of gettimeofday().
The issue has been noticed and reported due to a dhclient failure on the
CI20 board:
root@letux:~# dhclient
../../../../lib/isc/unix/time.c:200: Operation not permitted
root@letux:~#
Restore the original behavior fixing gettimeofday() in the vDSO library.
Reported-by: H. Nikolaus Schaller <hns@goldelico.com>
Tested-by: H. Nikolaus Schaller <hns@goldelico.com> # CI20 with JZ4780
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Paul Burton <paulburton@kernel.org>
Cc: mips-creator-ci20-dev@googlegroups.com
Cc: letux-kernel@openphoenux.org
Cc: linux-mips@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
On some MIPS variants (e.g. MIPS r1), vDSO clock_mode is set to
VDSO_CLOCK_NONE.
When VDSO_CLOCK_NONE is set the expected kernel behavior is to fallback
on syscalls. To do that the generic vDSO library expects UULONG_MAX as
return value of __arch_get_hw_counter().
Fix __arch_get_hw_counter() on MIPS defining a __VDSO_USE_SYSCALL case
that addressed the described scenario.
Reported-by: Maxime Bizon <mbizon@freebox.fr>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Tested-by: Maxime Bizon <mbizon@freebox.fr>
Signed-off-by: Paul Burton <paulburton@kernel.org>
Cc: linux-mips@vger.kernel.org
The generic vDSO library provides an implementation of clock_getres()
that can be leveraged by each architecture.
Add clock_getres() entry point on mips.
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paul.burton@mips.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Paul Burton <paul.burton@mips.com>
The mips vDSO library requires some adaptations to take advantage of the
newly introduced generic vDSO library.
Introduce the following changes:
- Modification of vdso.c to be compliant with the common vdso datapage
- Use of lib/vdso for gettimeofday
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paul.burton@mips.com>
Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
[paul.burton@mips.com: Prepend $(src) to config-n32-o32-env.c path.]
Signed-off-by: Paul Burton <paul.burton@mips.com>
