Our VDSO code makes use of macros from linux/irqchip/mips-gic.h to
provide offsets to register values, but these are trivial offsets to the
two 32 bit halves of a 64 bit value. Replace use of the macros with zero
(ie. omit adding an offset) and the size of the low 32 bit of the value.
This removes our need for linux/irqchip/mips-gic.h & prepares us for it
to be removed.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Acked-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17047/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
With Coherence Manager (CM) 3.5 information about the topology of the
system, which has previously only been available through & accessed from
the CM, is now also provided by the Cluster Power Controller (CPC). This
includes a new CPC_CONFIG register mirroring GCR_CONFIG, and similarly a
new CPC_Cx_CONFIG register mirroring GCR_Cx_CONFIG.
In preparation for adjusting functions such as mips_cm_numcores(), which
have previously only needed to access the CM, to also access the CPC
this patch modifies the way we use the various CPS headers. Rather than
having users include asm/mips-cm.h or asm/mips-cpc.h individually we
instead have users include asm/mips-cps.h which in turn includes
asm/mips-cm.h & asm/mips-cpc.h. This means that users will gain access
to both CM & CPC registers by including one header, and most importantly
it makes asm/mips-cps.h an ideal location for helper functions which
need to access the various components of the CPS.
Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/17015/
Patchwork: https://patchwork.linux-mips.org/patch/17217/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Extend clobber lists to include all GP registers.
Fixes: 0b523a85e1 ("MIPS: VDSO: Add implementation of gettimeofday() fallback")
Signed-off-by: Miodrag Dinic <miodrag.dinic@imgtec.com>
Signed-off-by: Goran Ferenc <goran.ferenc@imgtec.com>
Signed-off-by: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
Reviewed-by: James Hogan <james.hogan@imgtec.com>
Cc: Bo Hu <bohu@google.com>
Cc: Douglas Leung <douglas.leung@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Jin Qian <jinqian@google.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Petar Jovanovic <petar.jovanovic@imgtec.com>
Cc: Raghu Gandham <raghu.gandham@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/16879/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This patch adds gettimeofday_fallback() function that wraps assembly
invocation of gettimeofday() syscall using __NR_gettimeofday.
This function is used if pure VDSO implementation gettimeofday()
does not succeed for any reason. Its imeplementation is enclosed in
"#ifdef CONFIG_MIPS_CLOCK_VSYSCALL" to be in sync with the similar
arrangement for __vdso_gettimeofday().
If syscall invocation via __NR_gettimeofday fails, register a3 will
be set. So, after the syscall, register a3 is tested and the return
valuem is negated if it's set.
Signed-off-by: Goran Ferenc <goran.ferenc@imgtec.com>
Signed-off-by: Miodrag Dinic <miodrag.dinic@imgtec.com>
Signed-off-by: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
Cc: Douglas Leung <douglas.leung@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Petar Jovanovic <petar.jovanovic@imgtec.com>
Cc: Raghu Gandham <raghu.gandham@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/16640/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This patch adds clock_gettime_fallback() function that wraps assembly
invocation of clock_gettime() syscall using __NR_clock_gettime.
This function is used if pure VDSO implementation of clock_gettime()
does not succeed for any reason. For example, it is called if the
clkid parameter of clock_gettime() is not one of the clkids listed
in the switch-case block of the function __vdso_clock_gettime()
(one such case for clkid is CLOCK_BOOTIME).
If syscall invocation via __NR_clock_gettime fails, register a3 will
be set. So, after the syscall, register a3 is tested and the return
value is negated if it's set.
Signed-off-by: Goran Ferenc <goran.ferenc@imgtec.com>
Signed-off-by: Miodrag Dinic <miodrag.dinic@imgtec.com>
Signed-off-by: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
Cc: Douglas Leung <douglas.leung@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Petar Jovanovic <petar.jovanovic@imgtec.com>
Cc: Raghu Gandham <raghu.gandham@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/16639/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Fix incorrect calculation in do_monotonic() and do_monotonic_coarse()
function that in turn caused incorrect values returned by the vdso
version of system call clock_gettime() on mips64 if its system clock
ID parameter was CLOCK_MONOTONIC or CLOCK_MONOTONIC_COARSE.
Consider these variables and their types on mips32 and mips64:
tk->wall_to_monotonic.tv_sec s64, s64 (kernel/vdso.c)
vdso_data.wall_to_mono_sec u32, u32 (kernel/vdso.c)
to_mono_sec u32, u32 (vdso/gettimeofday.c)
ts->tv_sec s32, s64 (vdso/gettimeofday.c)
For mips64 case, u32 vdso_data.wall_to_mono_sec variable is updated
from the 64-bit signed variable tk->wall_to_monotonic.tv_sec
(kernel/vdso.c:76) which is a negative number holding the time passed
from 1970-01-01 to the time boot started. This 64-bit signed value is
currently around 47+ years, in seconds. For instance, let this value
be:
-1489757461
or
11111111111111111111111111111111 10100111001101000001101011101011
By updating 32-bit vdso_data.wall_to_mono_sec variable, we lose upper
32 bits (signed 1's).
to_mono_sec variable is a parameter of do_monotonic() and
do_monotonic_coarse() functions which holds vdso_data.wall_to_mono_sec
value. Its value needs to be added (or subtracted considering it holds
negative value from the tk->wall_to_monotonic.tv_sec) to the current
time passed from 1970-01-01 (ts->tv_sec), which is again something like
47+ years, but increased by the time passed from the boot to the
current time. ts->tv_sec is 32-bit long in case of 32-bit architecture
and 64-bit long in case of 64-bit architecture. Consider the update of
ts->tv_sec (vdso/gettimeofday.c:55 & 167):
ts->tv_sec += to_mono_sec;
mips32 case: This update will be performed correctly, since both
ts->tv_sec and to_mono_sec are 32-bit long and the sign in to_mono_sec
is preserved. Implicit conversion from u32 to s32 will be done
correctly.
mips64 case: This update will be wrong, since the implicit conversion
will not be done correctly. The reason is that the conversion will be
from u32 to s64. This is because to_mono_sec is 32-bit long for both
mips32 and mips64 cases and s64..33 bits of converted to_mono_sec
variable will be zeros.
So, in order to make MIPS64 implementation work properly for
MONOTONIC and MONOTONIC_COARSE clock ids on mips64, the size of
wall_to_mono_sec variable in mips_vdso_data union and respective
parameters in do_monotonic() and do_monotonic_coarse() functions
should be changed from u32 to u64. Because of consistency, this
size change from u32 and u64 is also done for wall_to_mono_nsec
variable and corresponding function parameters.
As far as similar situations for other architectures are concerned,
let's take a look at arm. Arm has two distinct vdso_data structures
for 32-bit & 64-bit cases, and arm's wall_to_mono_sec and
wall_to_mono_nsec are u32 for 32-bit and u64 for 64-bit cases.
On the other hand, MIPS has only one structure (mips_vdso_data),
hence the need for changing the size of above mentioned parameters.
Signed-off-by: Goran Ferenc <goran.ferenc@imgtec.com>
Signed-off-by: Miodrag Dinic <miodrag.dinic@imgtec.com>
Signed-off-by: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
Cc: Douglas Leung <douglas.leung@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Paul Burton <paul.burton@imgtec.com>
Cc: Petar Jovanovic <petar.jovanovic@imgtec.com>
Cc: Raghu Gandham <raghu.gandham@imgtec.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/16638/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Add user-mode implementations of gettimeofday() and clock_gettime() to
the VDSO. This is currently usable with 2 clocksources: the CP0 count
register, which is accessible to user-mode via RDHWR on R2 and later
cores, or the MIPS Global Interrupt Controller (GIC) timer, which
provides a "user-mode visible" section containing a mirror of its
counter registers. This section must be mapped into user memory, which
is done below the VDSO data page.
When a supported clocksource is not in use, the VDSO functions will
return -ENOSYS, which causes libc to fall back on the standard syscall
path.
When support for neither of these clocksources is compiled into the
kernel at all, the VDSO still provides clock_gettime(), as the coarse
realtime/monotonic clocks can still be implemented. However,
gettimeofday() is not provided in this case as nothing can be done
without a suitable clocksource. This causes the symbol lookup to fail
in libc and it will then always use the standard syscall path.
This patch includes a workaround for a bug in QEMU which results in
RDHWR on the CP0 count register always returning a constant (incorrect)
value. A fix for this has been submitted, and the workaround can be
removed after the fix has been in stable releases for a reasonable
amount of time.
A simple performance test which calls gettimeofday() 1000 times in a
loop and calculates the average execution time gives the following
results on a Malta + I6400 (running at 20MHz):
- Syscall: ~31000 ns
- VDSO (GIC): ~15000 ns
- VDSO (CP0): ~9500 ns
[markos.chandras@imgtec.com:
- Minor code re-arrangements in order for mappings to be made
in the order they appear to the process' address space.
- Move do_{monotonic, realtime} outside of the MIPS_CLOCK_VSYSCALL ifdef
- Use gic_get_usm_range so we can do the GIC mapping in the
arch/mips/kernel/vdso instead of the GIC irqchip driver]
Signed-off-by: Alex Smith <alex.smith@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11338/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Paul Burton