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s/commiting/committing/
s/defintion/definition/
s/gaurantees/guarantees/
s/interrpted/interrupted/
s/interrutps/interrupts/
s/succeded/succeeded/
s/unconditonally/unconditionally/
Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Bhaskar Chowdhury <unixbhaskar@gmail.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
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PF_IO_WORKER are kernel threads too, but they aren't PF_KTHREAD in the
sense that we don't assign ->set_child_tid with our own structure. Just
ensure that every arch sets up the PF_IO_WORKER threads like kthreads
in the arch implementation of copy_thread().
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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NPS customers are no longer doing active development, as evident from
rand config build failures reported in recent times, so drop support
for NPS platform.
Tested-by: kernel test robot <lkp@intel.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
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After the cleanup of page fault accounting, gup does not need to pass
task_struct around any more. Remove that parameter in the whole gup
stack.
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Link: http://lkml.kernel.org/r/20200707225021.200906-26-peterx@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Pull regset conversion fix from Al Viro:
"Fix a regression from an unnoticed bisect hazard in the regset series.
A bunch of old (aout, originally) primitives used by coredumps became
dead code after fdpic conversion to regsets. Removal of that dead code
had been the first commit in the followups to regset series;
unfortunately, it happened to hide the bisect hazard on sh (extern for
fpregs_get() had not been updated in the main series when it should
have been; followup simply made fpregs_get() static). And without that
followup commit this bisect hazard became breakage in the mainline"
Tested-by: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
kill unused dump_fpu() instances
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dump_fpu() is used only on the architectures that support elf
and have neither CORE_DUMP_USE_REGSET nor ELF_CORE_COPY_FPREGS
defined.
Currently that's csky, m68k, microblaze, nds32 and unicore32. The rest
of the instances are dead code.
NB: THIS MUST GO AFTER ELF_FDPIC CONVERSION
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Now that HAVE_COPY_THREAD_TLS has been removed, rename copy_thread_tls()
back simply copy_thread(). It's a simpler name, and doesn't imply that only
tls is copied here. This finishes an outstanding chunk of internal process
creation work since we've added clone3().
Cc: linux-arch@vger.kernel.org
Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>A
Acked-by: Stafford Horne <shorne@gmail.com>
Acked-by: Greentime Hu <green.hu@gmail.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>A
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
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This change converts the existing mmap_sem rwsem calls to use the new mmap
locking API instead.
The change is generated using coccinelle with the following rule:
// spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir .
@@
expression mm;
@@
(
-init_rwsem
+mmap_init_lock
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-down_write
+mmap_write_lock
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-down_write_killable
+mmap_write_lock_killable
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-down_write_trylock
+mmap_write_trylock
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-up_write
+mmap_write_unlock
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-downgrade_write
+mmap_write_downgrade
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-down_read
+mmap_read_lock
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-down_read_killable
+mmap_read_lock_killable
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-down_read_trylock
+mmap_read_trylock
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-up_read
+mmap_read_unlock
)
-(&mm->mmap_sem)
+(mm)
Signed-off-by: Michel Lespinasse <walken@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Liam Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ying Han <yinghan@google.com>
Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
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Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull force_sig() argument change from Eric Biederman:
"A source of error over the years has been that force_sig has taken a
task parameter when it is only safe to use force_sig with the current
task.
The force_sig function is built for delivering synchronous signals
such as SIGSEGV where the userspace application caused a synchronous
fault (such as a page fault) and the kernel responded with a signal.
Because the name force_sig does not make this clear, and because the
force_sig takes a task parameter the function force_sig has been
abused for sending other kinds of signals over the years. Slowly those
have been fixed when the oopses have been tracked down.
This set of changes fixes the remaining abusers of force_sig and
carefully rips out the task parameter from force_sig and friends
making this kind of error almost impossible in the future"
* 'siginfo-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace: (27 commits)
signal/x86: Move tsk inside of CONFIG_MEMORY_FAILURE in do_sigbus
signal: Remove the signal number and task parameters from force_sig_info
signal: Factor force_sig_info_to_task out of force_sig_info
signal: Generate the siginfo in force_sig
signal: Move the computation of force into send_signal and correct it.
signal: Properly set TRACE_SIGNAL_LOSE_INFO in __send_signal
signal: Remove the task parameter from force_sig_fault
signal: Use force_sig_fault_to_task for the two calls that don't deliver to current
signal: Explicitly call force_sig_fault on current
signal/unicore32: Remove tsk parameter from __do_user_fault
signal/arm: Remove tsk parameter from __do_user_fault
signal/arm: Remove tsk parameter from ptrace_break
signal/nds32: Remove tsk parameter from send_sigtrap
signal/riscv: Remove tsk parameter from do_trap
signal/sh: Remove tsk parameter from force_sig_info_fault
signal/um: Remove task parameter from send_sigtrap
signal/x86: Remove task parameter from send_sigtrap
signal: Remove task parameter from force_sig_mceerr
signal: Remove task parameter from force_sig
signal: Remove task parameter from force_sigsegv
...
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Based on 2 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 4122 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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All of the remaining callers pass current into force_sig so
remove the task parameter to make this obvious and to make
misuse more difficult in the future.
This also makes it clear force_sig passes current into force_sig_info.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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The function force_sigsegv is always called on the current task
so passing in current is redundant and not passing in current
makes this fact obvious.
This also makes it clear force_sigsegv always calls force_sig
on the current task.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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Nobody has actually used the type (VERIFY_READ vs VERIFY_WRITE) argument
of the user address range verification function since we got rid of the
old racy i386-only code to walk page tables by hand.
It existed because the original 80386 would not honor the write protect
bit when in kernel mode, so you had to do COW by hand before doing any
user access. But we haven't supported that in a long time, and these
days the 'type' argument is a purely historical artifact.
A discussion about extending 'user_access_begin()' to do the range
checking resulted this patch, because there is no way we're going to
move the old VERIFY_xyz interface to that model. And it's best done at
the end of the merge window when I've done most of my merges, so let's
just get this done once and for all.
This patch was mostly done with a sed-script, with manual fix-ups for
the cases that weren't of the trivial 'access_ok(VERIFY_xyz' form.
There were a couple of notable cases:
- csky still had the old "verify_area()" name as an alias.
- the iter_iov code had magical hardcoded knowledge of the actual
values of VERIFY_{READ,WRITE} (not that they mattered, since nothing
really used it)
- microblaze used the type argument for a debug printout
but other than those oddities this should be a total no-op patch.
I tried to fix up all architectures, did fairly extensive grepping for
access_ok() uses, and the changes are trivial, but I may have missed
something. Any missed conversion should be trivially fixable, though.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Per ARC TLS ABI, r25 is designated TP (thread pointer register).
However so far kernel didn't do any special treatment, like setting up
usermode r25, even for CLONE_SETTLS. We instead relied on libc runtime
to do this, in say clone libc wrapper [1]. This was deliberate to keep
kernel ABI agnostic (userspace could potentially change TP, specially
for different ARC ISA say ARCompact vs. ARCv2 with different spare
registers etc)
However userspace setting up r25, after clone syscall opens a race, if
child is not scheduled and gets a signal instead. It starts off in
userspace not in clone but in a signal handler and anything TP sepcific
there such as pthread_self() fails which showed up with uClibc
testsuite nptl/tst-kill6 [2]
Fix this by having kernel populate r25 to TP value. So this locks in
ABI, but it was not going to change anyways, and fwiw is same for both
ARCompact (arc700 core) and ARCvs (HS3x cores)
[1] https://cgit.uclibc-ng.org/cgi/cgit/uclibc-ng.git/tree/libc/sysdeps/linux/arc/clone.S
[2] https://github.com/wbx-github/uclibc-ng-test/blob/master/test/nptl/tst-kill6.c
Fixes: ARC STAR 9001378481
Cc: stable@vger.kernel.org
Reported-by: Nikita Sobolev <sobolev@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
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This is used in configs lacking hardware atomics to emulate atomic r-m-w
for user space, implemented by disabling preemption in kernel.
However there are issues in current implementation:
1. Process not terminated if invalid user pointer passed:
i.e. __get_user() failed.
2. The reason for this patch was __put_user() failure not being handled
either, specifically for the COW break scenario.
The zero page is initially wired up and read from __get_user()
succeeds. A subsequent write by __put_user() induces a
Protection Violation, but COW can't finish as Linux page fault
handler is disabled due to preempt disable.
And what's worse is we silently return the stale value to user space.
Fix this specific case by re-enabling preemption and explicitly
fixing up the fault and retrying the whole sequence over.
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: linux-arch@vger.kernel.org
Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
[vgupta: rewrote the changelog]
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Preserve eflags and gpa1 aux during entry/exit into kernel as these
could be modified by kernel mode
These registers used by compare exchange instructions.
- GPA1 is used for compare value,
- EFLAGS got bit reflects atomic operation response.
EFLAGS is zeroed for each new user task so it won't get its
parent value.
Signed-off-by: Liav Rehana <liavr@mellanox.com>
Signed-off-by: Noam Camus <noamc@ezchip.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
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When HW threads are active we want CPU to enter idle state only
for the calling HW thread and not to put on sleep all HW threads
sharing this core. For this need the NPS400 got dedicated instruction
so only calling thread is entring sleep and all other are still awake
and can execute instructions.
Signed-off-by: Noam Camus <noamca@mellanox.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
[vgupta: reworked patch to not use inline ifdef but a new function itself]
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This paves way for creating a 3rd variant needed for NPS ARC700 without
littering ifdey'ery all over the place
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
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<linux/sched/task_stack.h>
We are going to split <linux/sched/task_stack.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.
Create a trivial placeholder <linux/sched/task_stack.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.
Include the new header in the files that are going to need it.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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<linux/sched/task.h>
We are going to split <linux/sched/task.h> out of <linux/sched.h>, which
will have to be picked up from other headers and a couple of .c files.
Create a trivial placeholder <linux/sched/task.h> file that just
maps to <linux/sched.h> to make this patch obviously correct and
bisectable.
Include the new header in the files that are going to need it.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The original syscall only used to return errno to indicate if cmpxchg
succeeded. It was not returning the "previous" value which typical cmpxchg
callers are interested in to build their slowpaths or retry loops.
Given user preemption in syscall return path etc, it is not wise to
check this in userspace afterwards, but should be what kernel actually
observed in the syscall.
So change the syscall interface to always return the previous value and
additionally set Z flag to indicate whether operation succeeded or not
(just like ARM implementation when they used to have this syscall)
The flag approach avoids having to put_user errno which is nice given
the use case for this syscall cares mostly about the "previous" value.
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
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Older ARC700 cores (ARC750 specifically) lack instructions to implement
atomic r-w-w. This is problematic for userspace libraries such as NPTL
which need atomic primitives. So enable them by providing kernel assist.
This is costly but really the only sane soluton (othern than tight
spinning using the otherwise availiable atomic exchange EX instruciton).
Good thing is there are only a few of these cores running Linux out in
the wild.
This only works on UP systems.
Reviewed-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
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The syscall ABI includes the gcc functional calling ABI since a syscall
implies userland caller and kernel callee.
The current gcc ABI (v3) for ARCv2 ISA required 64-bit data be passed in
even-odd register pairs, (potentially punching reg holes when passing such
values as args). This was partly driven by the fact that the double-word
LDD/STD instructions in ARCv2 expect the register alignment and thus gcc
forcing this avoids extra MOV at the cost of a few unused register (which we
have plenty anyways).
This however was rejected as part of upstreaming gcc port to HS. So the new
ABI v4 doesn't enforce the even-odd reg restriction.
Do note that for ARCompact ISA builds v3 and v4 are practically the same in
terms of gcc code generation.
In terms of change management, we infer the new ABI if gcc 6.x onwards
is used for building the kernel.
This also needs a stable backport to enable older kernels to work with
new tools/user-space
Cc: <stable@vger.kernel.org>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
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Define HAVE_EXIT_THREAD for archs which want to do something in
exit_thread. For others, let's define exit_thread as an empty inline.
This is a cleanup before we change the prototype of exit_thread to
accept a task parameter.
[akpm@linux-foundation.org: fix mips]
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chen Liqin <liqin.linux@gmail.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: David Howells <dhowells@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
Cc: Lennox Wu <lennox.wu@gmail.com>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Steven Miao <realmz6@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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No semantical changes, prepares for ARCv2 specific change in next commit
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
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Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
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Reported-by: Guenter Roeck <private@roeck-us.net>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
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The notable features are:
- SMP configurations of upto 4 cores with coherency
- Optional L2 Cache and IO-Coherency
- Revised Interrupt Architecture (multiple priorites, reg banks,
auto stack switch, auto regfile save/restore)
- MMUv4 (PIPT dcache, Huge Pages)
- Instructions for
* 64bit load/store: LDD, STD
* Hardware assisted divide/remainder: DIV, REM
* Function prologue/epilogue: ENTER_S, LEAVE_S
* IRQ enable/disable: CLRI, SETI
* pop count: FFS, FLS
* SETcc, BMSKN, XBFU...
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
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Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc
Pull ARC updates from Vineet Gupta:
- perf fixes/improvements
- misc cleanups
* tag 'arc-4.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
ARC: perf: don't add code for impossible case
ARC: perf: Rename DT binding to not confuse with power mgmt
ARC: perf: add user space attribution in callchains
ARC: perf: Add kernel callchain support
ARC: perf: support cache hit/miss ratio
ARC: perf: Add some comments/debug stuff
ARC: perf: make @arc_pmu static global
ARC: mem init spring cleaning - No functional changes
ARC: Fix RTT boot printing
ARC: fold __builtin_constant_p() into test_bit()
ARC: rename unhandled exception handler
ARC: cosmetic: Remove unused ECR bitfield masks
ARC: Fix WRITE_BCR
ARC: [nsimosci] Update defconfig
arc: copy_thread(): rename 'arg' argument to 'kthread_arg'
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flush_old_exec() has already done that. Back on 2011 a bunch of
instances like that had been kicked out, but that hadn't taken
care of then-out-of-tree architectures, obviously, and they served
as reinfection vector...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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The 'arg' argument to copy_thread() is only ever used when forking a new
kernel thread. Hence, rename it to 'kthread_arg' for clarity.
Signed-off-by: Alex Dowad <alexinbeijing@gmail.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
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The old implementation assumed that SP at the time of __switch_to() is
right above pt_regs which is almost certainly not the case as there will
be some stack build up between entry into kernel and leading up to
__switch_to
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
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Helps move out ISA specific bits from a arch exported header
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
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pt_regs->event was set with artificial values to identify the low level
system event (syscall trap / breakpoint trap / exceptions / interrupts)
With r8 saving out of the way, the full word can be used to save real
ECR (Exception Cause Register) which helps idenify the event naturally,
including additional info such as cause code, param.
Only for Interrupts, where ECR is not applicable, do we resort to
synthetic non ECR values.
SAVE_ALL_TRAP/EXCEPTIONS can now be merged as they both use ECR with
different runtime values.
The ptrace helpers now use the sub-fields of ECR to distinguish the
events (e.g. vector 0x25 is trap, param 0 is syscall...)
The following benefits will follow:
(1) This centralizes the location of where ECR is saved and will allow
the cleanup of task->thread.cause_code ECR placeholder which is set
in non-uniform way. Then ARC VM code can safely rely on it being
there for purpose of finer grained VM_EXEC dcache flush (based on
exec fault: I-TLB Miss)
(2) Further, ECR being passed around from low level handlers as arg can
be eliminated as it is part of standard reg-file in pt_regs
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
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(This is a VERY IMP change for low level interrupt/exception handling)
-----------------------------------------------------------------------
WHAT
-----------------------------------------------------------------------
* User 25 now saved in pt_regs->user_r25 (vs. tsk->thread_info.user_r25)
* This allows Low level interrupt code to unconditionally save r25
(vs. the prev version which would only do it for U->K transition).
Ofcourse for nested interrupts, only the pt_regs->user_r25 of
bottom-most frame is useful.
* simplifies the interrupt prologue/epilogue
* Needed for ARCv2 ISA code and done here to keep design similar with
ARCompact event handling
-----------------------------------------------------------------------
WHY
-------------------------------------------------------------------------
With CONFIG_ARC_CURR_IN_REG, r25 is used to cache "current" task pointer
in kernel mode. So when entering kernel mode from User Mode
- user r25 is specially safe-kept (it being a callee reg is NOT part of
pt_regs which are saved by default on each interrupt/trap/exception)
- r25 loaded with current task pointer.
Further, if interrupt was taken in kernel mode, this is skipped since we
know that r25 already has valid "current" pointer.
With 2 level of interrupts in ARCompact ISA, detecting this is difficult
but still possible, since we could be in kernel mode but r25 not already saved
(in fact the stack itself might not have been switched).
A. User mode
B. L1 IRQ taken
C. L2 IRQ taken (while on 1st line of L1 ISR)
So in #C, although in kernel mode, r25 not saved (infact SP not
switched at all)
Given that ARcompact has manual stack switching, we could use a bit of
trickey - The low level code would make sure that SP is only set to kernel
mode value at the very end (after saving r25). So a non kernel mode SP,
even if in kernel mode, meant r25 was NOT saved.
The same paradigm won't work in ARCv2 ISA since SP is auto-switched so
it's setting can't be delayed/constrained.
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
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* use artificial PUSH/POP contructs for CORE Reg save/restore to stack
* use artificial PUSHAX/POPAX contructs for Auxiliary Space regs
* macro'ize multiple copies of callee-reg-save/restore (SAVE_R13_TO_R24)
* use BIC insn for inverse-and operation
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
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This is trickier than prev two:
* context switching code saves kernel mode callee regs in the format of
struct callee_regs thus needs adjustment. This also reduces the height
of topmost kernel stack frame by 1 word.
* Since kernel stack unwinder is sensitive to height of topmost kernel
stack frame, that needs a word of adjustment too.
ptrace needs a bit of updating since pt_regs now diverges from
user_regs_struct.
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
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Historically, pt_regs would end at offset of 1 word from end of stack
page.
----------------- -> START of page (task->stack)
| |
| thread_info |
-----------------
| |
^ ~ ~
| ~ ~
| | |
| | | <---- pt_regs used to END here
-----------------
| 1 word GUTTER |
----------------- -> End of page (START of kernel stack)
This required special "one-off" considerations in low level code.
The root cause is very likely assumption of "empty" SP by the original
ARC kernel hackers, despite ARC700 always been "full" SP.
So finally RIP one word gutter !
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
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The generic idle loop implements all functionality. Aside of that it
allows arc to implement the tsk_is_polling() functionality correctly,
despite the patently (now gone) comment in the original arc cpu_idle()
function:
/* Since we SLEEP in idle loop, TIF_POLLING_NRFLAG can't be set */
See kernel/cpu/idle.c
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Reviewed-by: Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Magnus Damm <magnus.damm@gmail.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Tested-by: Vineet Gupta <vgupta@synopsys.com>
Link: http://lkml.kernel.org/r/20130321215233.711253792@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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The upstream kernel ABI (v3) is different from current out-of-tree (v2):
* no-legacy-syscalls
* user_regs_struct layout has changed
So we rev up the ABI version
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
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Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Thomas Gleixner <tglx@linutronix.de>
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This includes support for generic clone/for/vfork/execve
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Acked-by: Arnd Bergmann <arnd@arndb.de>
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