ARC: __switch_to: move ksp to thread_info from thread_struct

task's arch specific bits are carried in 2 places
- embedded thread_struct in task_struct
- associated thread_info (hoisted in task's s

ARC: __switch_to: move ksp to thread_info from thread_struct

task's arch specific bits are carried in 2 places
- embedded thread_struct in task_struct
- associated thread_info (hoisted in task's stack page) and
syntactically: (thread_info *)(task_struct->stack)

ksp (dynamic kernel stack top) currently lives in thread_struct but
given its deep location in task struct likely to cache miss when
accessed from __switch_to(). Moving it to thread_info would be more
efficient given proximity to frequently accessed items such as
preempt_count thus very likely to be in cache, specially in schedular
code.

Note however that currently tsk.thread.ksp takes 1 memory access (off
of tsk pointer) while new code tsk->stack.ksp would take 2, but likely
to be in cache. Moreover if task is current the 2nd reference can be
elided and instead derived from SP as (SP & ~(THREAD_SIZE - 1))

All of this also makes __switch_to() code simpler and we can see the 2
ways of retirving ksp (descrobed above) in new code.

Signed-off-by: Vineet Gupta <[email protected]>

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ARC: kernel stack: INIT_THREAD need not setup @init_stack in @ksp

There are 2 pointers to kernel mode stack of a task
- task_struct.stack: base address of stack page (max possible stack top)
- thr

ARC: kernel stack: INIT_THREAD need not setup @init_stack in @ksp

There are 2 pointers to kernel mode stack of a task
- task_struct.stack: base address of stack page (max possible stack top)
- thread_info.ksp : runtime stack top in __switch_to

INIT_THREAD was setting up ksp to stack base which was not really needed
- it would get overwritten with dynamic value on first call to
__switch_to when init is switched out for the very first time.
- generic code already does
init_task.stack = init_stack
and ARC code uses that to retrieve task's stack base.

Signed-off-by: Vineet Gupta <[email protected]>

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kernel: exit: cleanup release_thread()

Only x86 has own release_thread(), introduce a new weak release_thread()
function to clean empty definitions in other ARCHs.

Link: https://lkml.kernel.org/r/2

kernel: exit: cleanup release_thread()

Only x86 has own release_thread(), introduce a new weak release_thread()
function to clean empty definitions in other ARCHs.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Kefeng Wang <[email protected]>
Acked-by: Guo Ren <[email protected]> [csky]
Acked-by: Russell King (Oracle) <[email protected]>
Acked-by: Geert Uytterhoeven <[email protected]>
Acked-by: Brian Cain <[email protected]>
Acked-by: Michael Ellerman <[email protected]> [powerpc]
Acked-by: Stafford Horne <[email protected]> [openrisc]
Acked-by: Catalin Marinas <[email protected]> [arm64]
Acked-by: Huacai Chen <[email protected]> [LoongArch]
Cc: Alexander Gordeev <[email protected]>
Cc: Anton Ivanov <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Christian Borntraeger <[email protected]>
Cc: Christophe Leroy <[email protected]>
Cc: Chris Zankel <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: "David S. Miller" <[email protected]>
Cc: Dinh Nguyen <[email protected]>
Cc: Guo Ren <[email protected]> [csky]
Cc: Heiko Carstens <[email protected]>
Cc: Helge Deller <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Ivan Kokshaysky <[email protected]>
Cc: James Bottomley <[email protected]>
Cc: Johannes Berg <[email protected]>
Cc: Jonas Bonn <[email protected]>
Cc: Matt Turner <[email protected]>
Cc: Max Filippov <[email protected]>
Cc: Michal Simek <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Palmer Dabbelt <[email protected]>
Cc: Paul Walmsley <[email protected]>
Cc: Richard Henderson <[email protected]>
Cc: Richard Weinberger <[email protected]>
Cc: Rich Felker <[email protected]>
Cc: Stefan Kristiansson <[email protected]>
Cc: Sven Schnelle <[email protected]>
Cc: Thomas Bogendoerfer <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Vasily Gorbik <[email protected]>
Cc: Vineet Gupta <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Xuerui Wang <[email protected]>
Cc: Yoshinori Sato <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

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sched: Add wrapper for get_wchan() to keep task blocked

Having a stable wchan means the process must be blocked and for it to
stay that way while performing stack unwinding.

Suggested-by: Peter Zij

sched: Add wrapper for get_wchan() to keep task blocked

Having a stable wchan means the process must be blocked and for it to
stay that way while performing stack unwinding.

Suggested-by: Peter Zijlstra <[email protected]>
Signed-off-by: Kees Cook <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Acked-by: Geert Uytterhoeven <[email protected]>
Acked-by: Russell King (Oracle) <[email protected]> [arm]
Tested-by: Mark Rutland <[email protected]> [arm64]
Link: https://lkml.kernel.org/r/[email protected]

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ARC: mm: support 3 levels of page tables

ARCv2 MMU is software walked and Linux implements 2 levels of paging: pgd/pte.
Forthcoming hw will have multiple levels, so this change preps mm code
for sam

ARC: mm: support 3 levels of page tables

ARCv2 MMU is software walked and Linux implements 2 levels of paging: pgd/pte.
Forthcoming hw will have multiple levels, so this change preps mm code
for same. It is also fun to try multi levels even on soft-walked code to
ensure generic mm code is robust to handle.

overview
________

2 levels {pgd, pte} : pmd is folded but pmd_* macros are valid and operate on pgd
3 levels {pgd, pmd, pte}:
- pud is folded and pud_* macros point to pgd
- pmd_* macros operate on actual pmd

code changes
____________

1. #include <asm-generic/pgtable-nopud.h>

2. Define CONFIG_PGTABLE_LEVELS 3

3a. Define PMD_SHIFT, PMD_SIZE, PMD_MASK, pmd_t
3b. Define pmd_val() which actually deals with pmd
(pmd_offset(), pmd_index() are provided by generic code)
3c. pmd_alloc_one()/pmd_free() also provided by generic code
(pmd_populate/pmd_free already exist)

4. Define pud_none(), pud_bad() macros based on generic pud_val() which
internally pertains to pgd now.
4b. define pud_populate() to just setup pgd

Acked-by: Mike Rapoport <[email protected]>
Signed-off-by: Vineet Gupta <[email protected]>

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ARC: [plat-eznps]: Drop support for EZChip NPS platform

NPS customers are no longer doing active development, as evident from
rand config build failures reported in recent times, so drop support
for

ARC: [plat-eznps]: Drop support for EZChip NPS platform

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 <[email protected]>
Signed-off-by: Vineet Gupta <[email protected]>

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ARC: add support for DSP-enabled userspace applications

To be able to run DSP-enabled userspace applications we need to
save and restore following DSP-related registers:
At IRQ/exception entry/exit:

ARC: add support for DSP-enabled userspace applications

To be able to run DSP-enabled userspace applications we need to
save and restore following DSP-related registers:
At IRQ/exception entry/exit:
* DSP_CTRL (save it and reset to value suitable for kernel)
* ACC0_LO, ACC0_HI (we already save them as r58, r59 pair)
At context switch:
* ACC0_GLO, ACC0_GHI
* DSP_BFLY0, DSP_FFT_CTRL

Reviewed-by: Vineet Gupta <[email protected]>
Signed-off-by: Eugeniy Paltsev <[email protected]>
Signed-off-by: Vineet Gupta <[email protected]>

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ARC: fpu: declutter code, move bits out into fpu.h

Signed-off-by: Vineet Gupta <[email protected]>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

Based on 2 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of th

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

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 <[email protected]>
Reviewed-by: Enrico Weigelt <[email protected]>
Reviewed-by: Kate Stewart <[email protected]>
Reviewed-by: Allison Randal <[email protected]>
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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treewide: remove current_text_addr

Prefer _THIS_IP_ defined in linux/kernel.h.

Most definitions of current_text_addr were the same as _THIS_IP_, but
a few archs had inline assembly instead.

This p

treewide: remove current_text_addr

Prefer _THIS_IP_ defined in linux/kernel.h.

Most definitions of current_text_addr were the same as _THIS_IP_, but
a few archs had inline assembly instead.

This patch removes the final call site of current_text_addr, making all
of the definitions dead code.

[[email protected]: fix arch/csky/include/asm/processor.h]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Nick Desaulniers <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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arch: remove unused *_segments() macros/functions

Some architectures define the no-op macros/functions copy_segments,
release_segments and forget_segments. These are used nowhere in the
tree, so rem

arch: remove unused *_segments() macros/functions

Some architectures define the no-op macros/functions copy_segments,
release_segments and forget_segments. These are used nowhere in the
tree, so removed them.

Signed-off-by: Tobias Klauser <[email protected]>
Acked-by: Vineet Gupta <[email protected]> [for arch/arc]
Signed-off-by: Linus Torvalds <[email protected]>

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ARC: [plat-eznps] handle extra aux regs #1: save/restore on context switch

save EFLAGS, and GPA1 auxiliary registers during context switch,
since they may be changed by the new task in kernel mode,

ARC: [plat-eznps] handle extra aux regs #1: save/restore on context switch

save EFLAGS, and GPA1 auxiliary registers during context switch,
since they may be changed by the new task in kernel mode, while using atomic
ops e.g. cmpxchg.

Signed-off-by: Noam Camus <[email protected]>
Signed-off-by: Vineet Gupta <[email protected]>

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arch: remove unused macro/function thread_saved_pc()

The only user of thread_saved_pc() in non-arch-specific code was removed
in commit 8243d5597793 ("sched/core: Remove pointless printout in
sched_

arch: remove unused macro/function thread_saved_pc()

The only user of thread_saved_pc() in non-arch-specific code was removed
in commit 8243d5597793 ("sched/core: Remove pointless printout in
sched_show_task()"). Remove the implementations as well.

Some architectures use thread_saved_pc() in their arch-specific code.
Leave their thread_saved_pc() intact.

Signed-off-by: Tobias Klauser <[email protected]>
Acked-by: Geert Uytterhoeven <[email protected]>
Cc: Ingo Molnar <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

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locking/core: Provide common cpu_relax_yield() definition

No need to duplicate the same define everywhere. Since
the only user is stop-machine and the only provider is
s390, we can use a default imp

locking/core: Provide common cpu_relax_yield() definition

No need to duplicate the same define everywhere. Since
the only user is stop-machine and the only provider is
s390, we can use a default implementation of cpu_relax_yield()
in sched.h.

Suggested-by: Russell King <[email protected]>
Signed-off-by: Christian Borntraeger <[email protected]>
Reviewed-by: David Hildenbrand <[email protected]>
Acked-by: Russell King <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Martin Schwidefsky <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Noam Camus <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: linux-s390 <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

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locking/core, arch: Remove cpu_relax_lowlatency()

As there are no users left, we can remove cpu_relax_lowlatency()
implementations from every architecture.

Signed-off-by: Christian Borntraeger <bor

locking/core, arch: Remove cpu_relax_lowlatency()

As there are no users left, we can remove cpu_relax_lowlatency()
implementations from every architecture.

Signed-off-by: Christian Borntraeger <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Martin Schwidefsky <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Noam Camus <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Russell King <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Cc: <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

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locking/core: Introduce cpu_relax_yield()

For spinning loops people do often use barrier() or cpu_relax().
For most architectures cpu_relax and barrier are the same, but on
some architectures cpu_re

locking/core: Introduce cpu_relax_yield()

For spinning loops people do often use barrier() or cpu_relax().
For most architectures cpu_relax and barrier are the same, but on
some architectures cpu_relax can add some latency.
For example on power,sparc64 and arc, cpu_relax can shift the CPU
towards other hardware threads in an SMT environment.
On s390 cpu_relax does even more, it uses an hypercall to the
hypervisor to give up the timeslice.
In contrast to the SMT yielding this can result in larger latencies.
In some places this latency is unwanted, so another variant
"cpu_relax_lowlatency" was introduced. Before this is used in more
and more places, lets revert the logic and provide a cpu_relax_yield
that can be called in places where yielding is more important than
latency. By default this is the same as cpu_relax on all architectures.

Signed-off-by: Christian Borntraeger <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: Heiko Carstens <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Martin Schwidefsky <[email protected]>
Cc: Nicholas Piggin <[email protected]>
Cc: Noam Camus <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Russell King <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

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Fix typos

Signed-off-by: Andrea Gelmini <[email protected]>
Signed-off-by: Vineet Gupta <[email protected]>

ARC: [plat-eznps] Use dedicated cpu_relax()

Since the CTOP is SMT hardware multi-threaded, we need to hint
the HW that now will be a very good time to do a hardware
thread context switching. This is

ARC: [plat-eznps] Use dedicated cpu_relax()

Since the CTOP is SMT hardware multi-threaded, we need to hint
the HW that now will be a very good time to do a hardware
thread context switching. This is done by issuing the schd.rw
instruction (binary coded here so as to not require specific
revision of GCC to build the kernel).
sched.rw means that Thread becomes eligible for execution by
the threads scheduler after all pending read/write
transactions were completed.

Implementing cpu_relax_lowlatency() with barrier()
Since with current semantics of cpu_relax() it may take a
while till yielded CPU will get back.

Signed-off-by: Noam Camus <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Acked-by: Vineet Gupta <[email protected]>

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ARC: [plat-eznps] Use dedicated user stack top

NPS use special mapping right below TASK_SIZE.
Hence we need to lower STACK_TOP so that user stack won't
overlap NPS special mapping.

Signed-off-by: N

ARC: [plat-eznps] Use dedicated user stack top

NPS use special mapping right below TASK_SIZE.
Hence we need to lower STACK_TOP so that user stack won't
overlap NPS special mapping.

Signed-off-by: Noam Camus <[email protected]>
Acked-by: Vineet Gupta <[email protected]>

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ARC: Make vmalloc size configurable

On ARC, lower 2G of address space is translated and used for
- user vaddr space (region 0 to 5)
- unused kernel-user gutter (region 6)
- kernel vaddr space (re

ARC: Make vmalloc size configurable

On ARC, lower 2G of address space is translated and used for
- user vaddr space (region 0 to 5)
- unused kernel-user gutter (region 6)
- kernel vaddr space (region 7)

where each region simply represents 256MB of address space.

The kernel vaddr space of 256MB is used to implement vmalloc, modules
So far this was enough, but not on EZChip system with 4K CPUs (given
that per cpu mechanism uses vmalloc for allocating chunks)

So allow VMALLOC_SIZE to be configurable by expanding down into the unused
kernel-user gutter region which at default 256M was excessive anyways.

Also use _BITUL() to fix a build error since PGDIR_SIZE cannot use "1UL"
as called from assembly code in mm/tlbex.S

Signed-off-by: Noam Camus <[email protected]>
[vgupta: rewrote changelog, debugged bootup crash due to int vs. hex]
Acked-by: Vineet Gupta <[email protected]>

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ARC: cpu_relax() to be compiler barrier even for UP

cpu_relax() on ARC has been barrier only for SMP (and no-op for UP). Per
recent discussions, it is safer to make it a compiler barrier
uncondition

ARC: cpu_relax() to be compiler barrier even for UP

cpu_relax() on ARC has been barrier only for SMP (and no-op for UP). Per
recent discussions, it is safer to make it a compiler barrier
unconditionally.

Link: http://lkml.kernel.org/r/[email protected]
Acked-by: Peter Zijlstra <[email protected]>
Signed-off-by: Vineet Gupta <[email protected]>

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ARC: mm: HIGHMEM: kmap API implementation

Implement kmap* API for ARC.

This enables
- permanent kernel maps (pkmaps): :kmap() API
- fixmap : kmap_atomic()

We use a very simple/uniform approach f

ARC: mm: HIGHMEM: kmap API implementation

Implement kmap* API for ARC.

This enables
- permanent kernel maps (pkmaps): :kmap() API
- fixmap : kmap_atomic()

We use a very simple/uniform approach for both (unlike some of the other
arches). So fixmap doesn't use the customary compile time address stuff.
The important semantic is sleep'ability (pkmap) vs. not (fixmap) which
the API guarantees.

Note that this patch only enables highmem for subsequent PAE40 support
as there is no real highmem for ARC in pure 32-bit paradigm as explained
below.

ARC has 2:2 address split of the 32-bit address space with lower half
being translated (virtual) while upper half unstranslated
(0x8000_0000 to 0xFFFF_FFFF). kernel itself is linked at base of
unstranslated space (i.e. 0x8000_0000 onwards), which is mapped to say
DDR 0x0 by external Bus Glue logic (outside the core). So kernel can
potentially access 1.75G worth of memory directly w/o need for highmem.
(the top 256M is taken by uncached peripheral space from 0xF000_0000 to
0xFFFF_FFFF)

In PAE40, hardware can address memory beyond 4G (0x1_0000_0000) while
the logical/virtual addresses remain 32-bits. Thus highmem is required
for kernel proper to be able to access these pages for it's own purposes
(user space is agnostic to this anyways).

Signed-off-by: Alexey Brodkin <[email protected]>
Signed-off-by: Vineet Gupta <[email protected]>

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ARC: mm: document system mem map clearly

Signed-off-by: Vineet Gupta <[email protected]>

ARC: fix warning in sched due to thread_saved_pc()

Signed-off-by: Vineet Gupta <[email protected]>

ARC: Fix thread_saved_pc()

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 betw

ARC: Fix thread_saved_pc()

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 <[email protected]>

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