We want to move away from using SMT priority updates for cpu_relax, and
use a 'wait' instruction which is similar to x86. As well as being a
much better fit for what everybody else uses and tests with, priority
nops are stateful which is nasty (interrupts have to consider they might
be taken at a different priority), and they're expensive to execute,
similar to a mtSPR which can effect other threads in the pipe.
This has shown to give results that are less affected by code alignment
on benchmarks that cause a lot of spin waiting (e.g., rwsem contention
on unixbench filesystem benchmarks) on POWER10.
QEMU TCG only supports this instruction correctly since v7.1, versions
without the fix may cause hangs whne running POWER10 CPUs.
Reviewed-by: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Fix checkpatch warnings RE the macros]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220920122259.363092-2-npiggin@gmail.com
cvdso_call_time macro is very similar to cvdso_call macro.
Add a call_time argument to cvdso_call which is 0 by default
and set to 1 when using cvdso_call to call __c_kernel_time().
Return returned value as is with CR[SO] cleared when it is used
for time().
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/837a260ad86fc1ce297a562c2117fd69be5f7b5c.1642782130.git.christophe.leroy@csgroup.eu
HMT_xxx macros are macros for adjusting thread priority
(hardware multi-threading) are macros inherited from PPC64
via commit 5f7c690728 ("[PATCH] powerpc: Merged ppc_asm.h")
Those instructions are pointless on PPC32, but some common
fonctions like arch_cpu_idle() use them.
So make them empty on PPC32 to avoid those instructions.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/c5a07fadea33d640ad10cecf0ac8faaec1c524e0.1629898474.git.christophe.leroy@csgroup.eu
This patch adds the necessary glue to provide time namespaces.
Things are mainly copied from ARM64.
__arch_get_timens_vdso_data() calculates timens vdso data position
based on the vdso data position, knowing it is the next page in vvar.
This avoids having to redo the mflr/bcl/mflr/mtlr dance to locate
the page relative to running code position.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com> # vDSO parts
Acked-by: Andrei Vagin <avagin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/1a15495f80ec19a87b16cf874dbf7c3fa5ec40fe.1617209142.git.christophe.leroy@csgroup.eu
A large series adding wrappers for our interrupt handlers, so that irq/nmi/user
tracking can be isolated in the wrappers rather than spread in each handler.
Conversion of the 32-bit syscall handling into C.
A series from Nick to streamline our TLB flushing when using the Radix MMU.
Switch to using queued spinlocks by default for 64-bit server CPUs.
A rework of our PCI probing so that it happens later in boot, when more generic
infrastructure is available.
Two small fixes to allow 32-bit little-endian processes to run on 64-bit
kernels.
Other smaller features, fixes & cleanups.
Thanks to:
Alexey Kardashevskiy, Ananth N Mavinakayanahalli, Aneesh Kumar K.V, Athira
Rajeev, Bhaskar Chowdhury, Cédric Le Goater, Chengyang Fan, Christophe Leroy,
Christopher M. Riedl, Fabiano Rosas, Florian Fainelli, Frederic Barrat, Ganesh
Goudar, Hari Bathini, Jiapeng Chong, Joseph J Allen, Kajol Jain, Markus
Elfring, Michal Suchanek, Nathan Lynch, Naveen N. Rao, Nicholas Piggin, Oliver
O'Halloran, Pingfan Liu, Po-Hsu Lin, Qian Cai, Ram Pai, Randy Dunlap, Sandipan
Das, Stephen Rothwell, Tyrel Datwyler, Will Springer, Yury Norov, Zheng
Yongjun.
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Merge tag 'powerpc-5.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux
Pull powerpc updates from Michael Ellerman:
- A large series adding wrappers for our interrupt handlers, so that
irq/nmi/user tracking can be isolated in the wrappers rather than
spread in each handler.
- Conversion of the 32-bit syscall handling into C.
- A series from Nick to streamline our TLB flushing when using the
Radix MMU.
- Switch to using queued spinlocks by default for 64-bit server CPUs.
- A rework of our PCI probing so that it happens later in boot, when
more generic infrastructure is available.
- Two small fixes to allow 32-bit little-endian processes to run on
64-bit kernels.
- Other smaller features, fixes & cleanups.
Thanks to: Alexey Kardashevskiy, Ananth N Mavinakayanahalli, Aneesh
Kumar K.V, Athira Rajeev, Bhaskar Chowdhury, Cédric Le Goater, Chengyang
Fan, Christophe Leroy, Christopher M. Riedl, Fabiano Rosas, Florian
Fainelli, Frederic Barrat, Ganesh Goudar, Hari Bathini, Jiapeng Chong,
Joseph J Allen, Kajol Jain, Markus Elfring, Michal Suchanek, Nathan
Lynch, Naveen N. Rao, Nicholas Piggin, Oliver O'Halloran, Pingfan Liu,
Po-Hsu Lin, Qian Cai, Ram Pai, Randy Dunlap, Sandipan Das, Stephen
Rothwell, Tyrel Datwyler, Will Springer, Yury Norov, and Zheng Yongjun.
* tag 'powerpc-5.12-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (188 commits)
powerpc/perf: Adds support for programming of Thresholding in P10
powerpc/pci: Remove unimplemented prototypes
powerpc/uaccess: Merge raw_copy_to_user_allowed() into raw_copy_to_user()
powerpc/uaccess: Merge __put_user_size_allowed() into __put_user_size()
powerpc/uaccess: get rid of small constant size cases in raw_copy_{to,from}_user()
powerpc/64: Fix stack trace not displaying final frame
powerpc/time: Remove get_tbl()
powerpc/time: Avoid using get_tbl()
spi: mpc52xx: Avoid using get_tbl()
powerpc/syscall: Avoid storing 'current' in another pointer
powerpc/32: Handle bookE debugging in C in syscall entry/exit
powerpc/syscall: Do not check unsupported scv vector on PPC32
powerpc/32: Remove the counter in global_dbcr0
powerpc/32: Remove verification of MSR_PR on syscall in the ASM entry
powerpc/syscall: implement system call entry/exit logic in C for PPC32
powerpc/32: Always save non volatile GPRs at syscall entry
powerpc/syscall: Change condition to check MSR_RI
powerpc/syscall: Save r3 in regs->orig_r3
powerpc/syscall: Use is_compat_task()
powerpc/syscall: Make interrupt.c buildable on PPC32
...
The second argument of __kernel_clock_gettime64 points to a struct
__kernel_timespec, with 64-bit time_t, so use the clock_gettime64
syscall in the fallback function for the 32-bit VDSO. Similarly,
clock_getres_fallback should use the clock_getres_time64 syscall,
though it isn't yet called from the 32-bit VDSO.
Fixes: d0e3fc69d0 ("powerpc/vdso: Provide __kernel_clock_gettime64() on vdso32")
Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
[chleroy: Moved into a single #ifdef __powerpc64__ block]
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/0c0ab0eb3cc80687c326f76ff0dd5762b8812ecc.1610452505.git.christophe.leroy@csgroup.eu
Provides __kernel_clock_gettime64() on vdso32. This is the
64 bits version of __kernel_clock_gettime() which is
y2038 compliant.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201126131006.2431205-9-mpe@ellerman.id.au
On PPC64, the TOC pointer needs to be saved and restored.
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201126131006.2431205-7-mpe@ellerman.id.au
Prepare for switching VDSO to generic C implementation in following
patch. Here, we:
- Prepare the helpers to call the C VDSO functions
- Prepare the required callbacks for the C VDSO functions
- Prepare the clocksource.h files to define VDSO_ARCH_CLOCKMODES
- Add the C trampolines to the generic C VDSO functions
powerpc is a bit special for VDSO as well as system calls in the
way that it requires setting CR SO bit which cannot be done in C.
Therefore, entry/exit needs to be performed in ASM.
Implementing __arch_get_vdso_data() would clobber the link register,
requiring the caller to save it. As the ASM calling function already
has to set a stack frame and saves the link register before calling
the C vdso function, retriving the vdso data pointer there is lighter.
Implement __arch_vdso_capable() and always return true.
Provide vdso_shift_ns(), as the generic x >> s gives the following
bad result:
18: 35 25 ff e0 addic. r9,r5,-32
1c: 41 80 00 10 blt 2c <shift+0x14>
20: 7c 64 4c 30 srw r4,r3,r9
24: 38 60 00 00 li r3,0
...
2c: 54 69 08 3c rlwinm r9,r3,1,0,30
30: 21 45 00 1f subfic r10,r5,31
34: 7c 84 2c 30 srw r4,r4,r5
38: 7d 29 50 30 slw r9,r9,r10
3c: 7c 63 2c 30 srw r3,r3,r5
40: 7d 24 23 78 or r4,r9,r4
In our case the shift is always <= 32. In addition, the upper 32 bits
of the result are likely nul. Lets GCC know it, it also optimises the
following calculations.
With the patch, we get:
0: 21 25 00 20 subfic r9,r5,32
4: 7c 69 48 30 slw r9,r3,r9
8: 7c 84 2c 30 srw r4,r4,r5
c: 7d 24 23 78 or r4,r9,r4
10: 7c 63 2c 30 srw r3,r3,r5
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201126131006.2431205-6-mpe@ellerman.id.au
When we're building the compat VDSO we are building 32-bit code but in
the context of a 64-bit kernel configuration.
To make this work we need to be careful in some places when using
ifdefs to differentiate between CONFIG_PPC64 and __powerpc64__.
CONFIG_PPC64 indicates the kernel we're building is 64-bit, but it
doesn't tell us that we're currently building 64-bit code - we could
be building 32-bit code for the compat VDSO.
On the other hand __powerpc64__ tells us that we are currently
building 64-bit code (and therefore we must also be building a 64-bit
kernel).
In the case of get_tb() we want to use the 32-bit code sequence
regardless of whether the kernel we're building for is 64-bit or
32-bit, what matters is the word size of the current object. So we
need to check __powerpc64__ to decide if we use mftb() or the
mftbu()/mftb() sequence.
For mftb() the logic for CPU_FTR_CELL_TB_BUG only makes sense if we're
building 64-bit code, so guard that with a __powerpc64__ check.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201126131006.2431205-4-mpe@ellerman.id.au
In order to easily use get_tb() from C VDSO, move timebase
functions into a new header named asm/vdso/timebase.h
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201126131006.2431205-3-mpe@ellerman.id.au
cpu_relax() need to be in asm/vdso/processor.h to be used by
the C VDSO generic library.
Move it there.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201126131006.2431205-2-mpe@ellerman.id.au
