Legacy ARC700 processors (first generation of MMU enabled ARC cores) had
VIPT cached which could be configured such that they could alias.
Corresponding support in kernel (with all the obnoxious cache flush overhead)
was added in ARC port 10 years ago to support 1 silicon. That is long bygone
and we can let it RIP.
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Vineet Gupta <vgupta@kernel.org>
Add PFN_PTE_SHIFT, update_mmu_cache_range(), flush_dcache_folio()
and flush_icache_pages().
Change the PG_dc_clean flag from being per-page to per-folio (which means
it cannot always be set as we don't know that all pages in this folio were
cleaned). Enhance the internal flush routines to take the number of pages
to flush.
Link: https://lkml.kernel.org/r/20230802151406.3735276-9-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Vineet Gupta <vgupta@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
By taking GENERIC_IOREMAP method, the generic generic_ioremap_prot(),
generic_iounmap(), and their generic wrapper ioremap_prot(), ioremap() and
iounmap() are all visible and available to arch. Arch needs to provide
wrapper functions to override the generic versions if there's arch
specific handling in its ioremap_prot(), ioremap() or iounmap(). This
change will simplify implementation by removing duplicated code with
generic_ioremap_prot() and generic_iounmap(), and has the equivalent
functioality as before.
Here, add wrapper functions ioremap_prot() and iounmap() for arc's special
operation when ioremap_prot() and iounmap().
Link: https://lkml.kernel.org/r/20230706154520.11257-8-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Brian Cain <bcain@quicinc.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Chris Zankel <chris@zankel.net>
Cc: David Laight <David.Laight@ACULAB.COM>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Niklas Schnelle <schnelle@linux.ibm.com>
Cc: Rich Felker <dalias@libc.org>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
- boot log now clearly per ISA
- global struct cpuinfo_arc[] elimiated
- local struct struct arcinfo kept for passing info
between functions
Tested-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202308162101.Ve5jBg80-lkp@intel.com
Signed-off-by: Vineet Gupta <vgupta@kernel.org>
This is first step in eliminating struct cpuinfo_arc[NR_CPUS]
Back when we had just ARCompact ISA, the idea was to read/bit-fiddle
the BCRs once and and cache decoded information in a global struct ready
to use.
With ARCv2 it was modified to contained abstract / ISA agnostic
information.
However with ARCv3 there 's too much disparity to abstract in common
structures. So drop the entire decode once and store paradigm. Afterall
there's only 2 users of this machinery anyways: boot printing and
cat /proc/cpuinfo. None is performance critical to warrant locking away
resident memory per cpu.
This patch is first step in that direction
- decouples struct cpuinfo_arc_mmu from global struct cpuinfo_arc
- mmu code still has a trimmed down static version of
struct cpuinfo_arc_mmu to cache information needed in performance
critical code such as tlb flush routines
- folds read_decode_mmu_bcr() into arc_mmu_mumbojumbo()
- setup_processor() directly calls arc_mmu_init() and not via
arc_cpu_init()
Tested-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202308151213.qKZPMiyz-lkp@intel.com/
Signed-off-by: Vineet Gupta <vgupta@kernel.org>
Anrd reported [1] new compiler warnings due to -Wmissing-protype.
These are for non static functions mostly used in asm code hence not
exported already. Fix this by adding the prototypes.
[1] https://lore.kernel.org/lkml/20230810141947.1236730-1-arnd@kernel.org
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Vineet Gupta <vgupta@kernel.org>
These are cleanups for architecture specific header files:
- the comments in include/linux/syscalls.h have gone out of sync
and are really pointless, so these get removed
- The asm/bitsperlong.h header no longer needs to be architecture
specific on modern compilers, so use a generic version for newer
architectures that use new enough userspace compilers
- A cleanup for virt_to_pfn/virt_to_bus to have proper type
checking, forcing the use of pointers
-----BEGIN PGP SIGNATURE-----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=S/he
-----END PGP SIGNATURE-----
Merge tag 'asm-generic-6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic
Pull asm-generic updates from Arnd Bergmann:
"These are cleanups for architecture specific header files:
- the comments in include/linux/syscalls.h have gone out of sync and
are really pointless, so these get removed
- The asm/bitsperlong.h header no longer needs to be architecture
specific on modern compilers, so use a generic version for newer
architectures that use new enough userspace compilers
- A cleanup for virt_to_pfn/virt_to_bus to have proper type checking,
forcing the use of pointers"
* tag 'asm-generic-6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
syscalls: Remove file path comments from headers
tools arch: Remove uapi bitsperlong.h of hexagon and microblaze
asm-generic: Unify uapi bitsperlong.h for arm64, riscv and loongarch
m68k/mm: Make pfn accessors static inlines
arm64: memory: Make virt_to_pfn() a static inline
ARM: mm: Make virt_to_pfn() a static inline
asm-generic/page.h: Make pfn accessors static inlines
xen/netback: Pass (void *) to virt_to_page()
netfs: Pass a pointer to virt_to_page()
cifs: Pass a pointer to virt_to_page() in cifsglob
cifs: Pass a pointer to virt_to_page()
riscv: mm: init: Pass a pointer to virt_to_page()
ARC: init: Pass a pointer to virt_to_pfn() in init
m68k: Pass a pointer to virt_to_pfn() virt_to_page()
fs/proc/kcore.c: Pass a pointer to virt_addr_valid()
This does the simple pattern conversion of alpha, arc, csky, hexagon,
loongarch, nios2, sh, sparc32, and xtensa to the lock_mm_and_find_vma()
helper. They all have the regular fault handling pattern without odd
special cases.
The remaining architectures all have something that keeps us from a
straightforward conversion: ia64 and parisc have stacks that can grow
both up as well as down (and ia64 has special address region checks).
And m68k, microblaze, openrisc, sparc64, and um end up having extra
rules about only expanding the stack down a limited amount below the
user space stack pointer. That is something that x86 used to do too
(long long ago), and it probably could just be skipped, but it still
makes the conversion less than trivial.
Note that this conversion was done manually and with the exception of
alpha without any build testing, because I have a fairly limited cross-
building environment. The cases are all simple, and I went through the
changes several times, but...
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Functions that work on a pointer to virtual memory such as
virt_to_pfn() and users of that function such as
virt_to_page() are supposed to pass a pointer to virtual
memory, ideally a (void *) or other pointer. However since
many architectures implement virt_to_pfn() as a macro,
this function becomes polymorphic and accepts both a
(unsigned long) and a (void *).
Fix up the offending call in arch/arc with an explicit cast.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
clang produces a build failure on x86 for some randconfig builds after a
change that moves around code to mm/mm_init.c:
Cannot find symbol for section 2: .text.
mm/mm_init.o: failed
I have not been able to figure out why this happens, but the __weak
annotation on arch_has_descending_max_zone_pfns() is the trigger here.
Removing the weak function in favor of an open-coded Kconfig option check
avoids the problem and becomes clearer as well as better to optimize by
the compiler.
[arnd@arndb.de: fix logic bug]
Link: https://lkml.kernel.org/r/20230415081904.969049-1-arnd@kernel.org
Link: https://lkml.kernel.org/r/20230414080418.110236-1-arnd@kernel.org
Fixes: 9420f89db2 ("mm: move most of core MM initialization to mm/mm_init.c")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: SeongJae Park <sj@kernel.org>
Tested-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: kernel test robot <oliver.sang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Add 'volatile' to iounmap()'s argument to prevent build warnings.
This make it the same as other major architectures.
Placates these warnings: (12 such warnings)
../drivers/video/fbdev/riva/fbdev.c: In function 'rivafb_probe':
../drivers/video/fbdev/riva/fbdev.c:2067:42: error: passing argument 1 of 'iounmap' discards 'volatile' qualifier from pointer target type [-Werror=discarded-qualifiers]
2067 | iounmap(default_par->riva.PRAMIN);
Fixes: 1162b0701b ("ARC: I/O and DMA Mappings")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: linux-snps-arc@lists.infradead.org
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Vineet Gupta <vgupta@kernel.org>
- Remove one of the repeated 'call' in comment line 396.
- Delete the redundant word 'to', 'since'
Signed-off-by: Jilin Yuan <yuanjilin@cdjrlc.com>
Signed-off-by: Vineet Gupta <vgupta@kernel.org>
This enables ARCH_HAS_VM_GET_PAGE_PROT on the platform and exports
standard vm_get_page_prot() implementation via DECLARE_VM_GET_PAGE_PROT,
which looks up a private and static protection_map[] array. Subsequently
all __SXXX and __PXXX macros can be dropped which are no longer needed.
Link: https://lkml.kernel.org/r/20220711070600.2378316-23-anshuman.khandual@arm.com
Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Brian Cain <bcain@quicinc.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Chris Zankel <chris@zankel.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: WANG Xuerui <kernel@xen0n.name>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
I observed that for each of the shared file-backed page faults, we're very
likely to retry one more time for the 1st write fault upon no page. It's
because we'll need to release the mmap lock for dirty rate limit purpose
with balance_dirty_pages_ratelimited() (in fault_dirty_shared_page()).
Then after that throttling we return VM_FAULT_RETRY.
We did that probably because VM_FAULT_RETRY is the only way we can return
to the fault handler at that time telling it we've released the mmap lock.
However that's not ideal because it's very likely the fault does not need
to be retried at all since the pgtable was well installed before the
throttling, so the next continuous fault (including taking mmap read lock,
walk the pgtable, etc.) could be in most cases unnecessary.
It's not only slowing down page faults for shared file-backed, but also add
more mmap lock contention which is in most cases not needed at all.
To observe this, one could try to write to some shmem page and look at
"pgfault" value in /proc/vmstat, then we should expect 2 counts for each
shmem write simply because we retried, and vm event "pgfault" will capture
that.
To make it more efficient, add a new VM_FAULT_COMPLETED return code just to
show that we've completed the whole fault and released the lock. It's also
a hint that we should very possibly not need another fault immediately on
this page because we've just completed it.
This patch provides a ~12% perf boost on my aarch64 test VM with a simple
program sequentially dirtying 400MB shmem file being mmap()ed and these are
the time it needs:
Before: 650.980 ms (+-1.94%)
After: 569.396 ms (+-1.38%)
I believe it could help more than that.
We need some special care on GUP and the s390 pgfault handler (for gmap
code before returning from pgfault), the rest changes in the page fault
handlers should be relatively straightforward.
Another thing to mention is that mm_account_fault() does take this new
fault as a generic fault to be accounted, unlike VM_FAULT_RETRY.
I explicitly didn't touch hmm_vma_fault() and break_ksm() because they do
not handle VM_FAULT_RETRY even with existing code, so I'm literally keeping
them as-is.
Link: https://lkml.kernel.org/r/20220530183450.42886-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vineet Gupta <vgupta@kernel.org>
Acked-by: Guo Ren <guoren@kernel.org>
Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Acked-by: Christian Borntraeger <borntraeger@linux.ibm.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> [arm part]
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Stafford Horne <shorne@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Brian Cain <bcain@quicinc.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Richard Weinberger <richard@nod.at>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Janosch Frank <frankja@linux.ibm.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Will Deacon <will@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: David Hildenbrand <david@redhat.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Chris Zankel <chris@zankel.net>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Rich Felker <dalias@libc.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Helge Deller <deller@gmx.de>
Cc: Yoshinori Sato <ysato@users.osdn.me>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Various spelling mistakes in comments.
Detected with the help of Coccinelle.
Signed-off-by: Julia Lawall <Julia.Lawall@inria.fr>
Signed-off-by: Vineet Gupta <vgupta@kernel.org>
-----BEGIN PGP SIGNATURE-----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=UsL8
-----END PGP SIGNATURE-----
Merge tag 'arc-5.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc
Pull ARC fixes from Vineet Gupta:
"Nothing too exciting for now"
* tag 'arc-5.17-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc:
arc: use swap() to make code cleaner
arc: perf: Move static structs to where they're really used
ARC: perf: fix misleading comment about pmu vs counter stop
arc: Replace lkml.org links with lore
ARC: perf: Remove redundant initialization of variable idx
ARC: thread_info.h: correct two typos in a comment
Since commit 4064b98270 ("mm: allow VM_FAULT_RETRY for multiple
times") allowed VM_FAULT_RETRY for multiple times, the
FAULT_FLAG_ALLOW_RETRY bit of fault_flag will not be changed in the page
fault path, so the following check is no longer needed:
flags & FAULT_FLAG_ALLOW_RETRY
So just remove it.
[akpm@linux-foundation.org: coding style fixes]
Link: https://lkml.kernel.org/r/20211110123358.36511-1-zhengqi.arch@bytedance.com
Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Kirill Shutemov <kirill@shutemov.name>
Cc: Peter Xu <peterx@redhat.com>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Chengming Zhou <zhouchengming@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
As started by commit 05a5f51ca5 ("Documentation: Replace lkml.org
links with lore"), replace lkml.org links with lore to better use a
single source that's more likely to stay available long-term.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Vineet Gupta <vineetg@rivosinc.com>
We want to specify flags when hotplugging memory. Let's prepare to pass
flags to memblock_add_node() by adjusting all existing users.
Note that when hotplugging memory the system is already up and running
and we might have concurrent memblock users: for example, while we're
hotplugging memory, kexec_file code might search for suitable memory
regions to place kexec images. It's important to add the memory
directly to memblock via a single call with the right flags, instead of
adding the memory first and apply flags later: otherwise, concurrent
memblock users might temporarily stumble over memblocks with wrong
flags, which will be important in a follow-up patch that introduces a
new flag to properly handle add_memory_driver_managed().
Link: https://lkml.kernel.org/r/20211004093605.5830-4-david@redhat.com
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Shahab Vahedi <shahab@synopsys.com> [arch/arc]
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Jianyong Wu <Jianyong.Wu@arm.com>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since memblock_free() operates on a physical range, make its name
reflect it and rename it to memblock_phys_free(), so it will be a
logical counterpart to memblock_phys_alloc().
The callers are updated with the below semantic patch:
@@
expression addr;
expression size;
@@
- memblock_free(addr, size);
+ memblock_phys_free(addr, size);
Link: https://lkml.kernel.org/r/20210930185031.18648-6-rppt@kernel.org
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Juergen Gross <jgross@suse.com>
Cc: Shahab Vahedi <Shahab.Vahedi@synopsys.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- MM rework
+ Implementing up to 4 paging levels.
+ Enable STRICT_MM_TYPECHECK
+ switch pgtable_t back to struct page *
- Atomics rework / implementing relaxed accessors
- Retiring of legacy MMUv1,v2; ARC750 cores
- A few other build errors, typos
-----BEGIN PGP SIGNATURE-----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=hIYy
-----END PGP SIGNATURE-----
Merge tag 'arc-5.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc
Pull ARC updates from Vineet Gupta:
"Finally a big pile of changes for ARC (atomics/mm). These are from our
internal arc64 tree, preparing mainline for eventual arc64 support.
I'm spreading them out to avoid tsunami of patches in one release.
- MM rework:
- Implement up to 4 paging levels
- Enable STRICT_MM_TYPECHECK
- switch pgtable_t back to 'struct page *'
- Atomics rework / implement relaxed accessors
- Retire legacy MMUv1,v2; ARC750 cores
- A few other build errors, typos"
* tag 'arc-5.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc: (33 commits)
ARC: mm: vmalloc sync from kernel to user table to update PMD ...
ARC: mm: support 4 levels of page tables
ARC: mm: support 3 levels of page tables
ARC: mm: switch to asm-generic/pgalloc.h
ARC: mm: switch pgtable_t back to struct page *
ARC: mm: hack to allow 2 level build with 4 level code
ARC: mm: disintegrate pgtable.h into levels and flags
ARC: mm: disintegrate mmu.h (arcv2 bits out)
ARC: mm: move MMU specific bits out of entry code ...
ARC: mm: move MMU specific bits out of ASID allocator
ARC: mm: non-functional code movement/cleanup
ARC: mm: pmd_populate* to use the canonical set_pmd (and drop pmd_set)
ARC: ioremap: use more commonly used PAGE_KERNEL based uncached flag
ARC: mm: Enable STRICT_MM_TYPECHECKS
ARC: mm: Fixes to allow STRICT_MM_TYPECHECKS
ARC: mm: move mmu/cache externs out to setup.h
ARC: mm: remove tlb paranoid code
ARC: mm: use SCRATCH_DATA0 register for caching pgdir in ARCv2 only
ARC: retire MMUv1 and MMUv2 support
ARC: retire ARC750 support
...
... not PGD
vmalloc() sets up the kernel page table (starting from @swapper_pg_dir).
But when vmalloc area is accessed in context of a user task, say opening
terminal in n_tty_open(), the user page tables need to be synced from
kernel page tables so that TLB entry is created in "user context".
The old code was doing this incorrectly, as it was updating the user pgd
entry (first level itself) to point to kernel pud table (2nd level),
effectively yanking away the entire user space translation with kernel one.
The correct way to do this is to ONLY update a user space pgd/pud/pmd entry
if it is not popluated already. This ensures that only the missing leaf
pmd entry gets updated to point to relevant kernel pte table.
From code change pov, we are chaging the pattern:
p4d = p4d_offset(pgd, address);
p4d_k = p4d_offset(pgd_k, address);
if (!p4d_present(*p4d_k))
goto bad_area;
set_p4d(p4d, *p4d_k);
with
p4d = p4d_offset(pgd, address);
p4d_k = p4d_offset(pgd_k, address);
if (p4d_none(*p4d_k))
goto bad_area;
if (!p4d_present(*p4d))
set_p4d(p4d, *p4d_k);
Signed-off-by: Vineet Gupta <vgupta@kernel.org>
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 <rppt@linux.ibm.com>
Signed-off-by: Vineet Gupta <vgupta@kernel.org>
So far ARC pgtable_t has not been struct page based to avoid extra
page_address() calls involved. However the differences are down to
noise and get in the way of using generic code, hence this patch.
This also allows us to reuse generic THP depost/withdraw code.
There's some additional consideration for PGDIR_SHIFT in 4K page config.
Now due to page tables being PAGE_SIZE deep only, the address split
can't be really arbitrary.
Tested-by: kernel test robot <lkp@intel.com>
Suggested-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Vineet Gupta <vgupta@kernel.org>
PMD_SHIFT is mapped to PUD_SHIFT or PGD_SHIFT by asm-generic/pgtable-*
but only for !__ASSEMBLY__
tlbex.S asm code has PTRS_PER_PTE which uses PMD_SHIFT hence barfs
for CONFIG_PGTABLE_LEVEL={2,3} and works for 4.
So add a workaround local to tlbex.S - the proper fix is to change
asm-generic/pgtable-* headers to expose the defines for __ASSEMBLY__ too
Signed-off-by: Vineet Gupta <vgupta@kernel.org>
In the past I've refrained from doing this (at least 2 times) due to the
slight code bloat due to ABI implications of pte_t etc becoming struct
Per ARC ABI, functions return struct via memory and not through register
r0, even if the struct would fit in register(s)
- caller allocates space on stack and passes the address as first arg
(r0), shifting rest of args by one
- callee creates return struct in memory (referenced via r0)
This time around the code actually shrunk slightly (due to subtle
inlining heuristic effects), but still slightly inefficient due to
return values passed through memory. That however seems like a small
cost compared to maintenance burden given the impending new mmu support
for page walk etc
Signed-off-by: Vineet Gupta <vgupta@kernel.org>
MMU SCRATCH_DATA0 register is intended to cache task pgd. However in
ARC700 SMP port, it has to be repurposed for re-entrant interrupt
handling, while UP port doesn't. We currently handle these use-cases
using a fabricated #define which has usual issues of dependency nesting
and obvious ugliness.
So clean this up: for ARC700 don't use to cache pgd (even in UP) and do
the opposite for ARCv2.
And while here, switch to canonical pgd_offset().
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Vineet Gupta <vgupta@kernel.org>
There's no known/active customer using them with latest kernels anyways.
Removal helps cleanup code and remove the hack for
MMU_VER to MMU_V[3-4] conversion
Signed-off-by: Vineet Gupta <vgupta@kernel.org>
0day bot reports a build error:
ERROR: modpost: "clear_user_page" [drivers/media/v4l2-core/videobuf-dma-sg.ko] undefined!
so export it in arch/arc/ to fix the build error.
In most ARCHes, clear_user_page() is a macro. OTOH, in a few
ARCHes it is a function and needs to be exported.
PowerPC exported it in 2004. It looks like nds32 and nios2
still need to have it exported.
Fixes: 4102b53392 ("ARC: [mm] Aliasing VIPT dcache support 2/4")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: linux-snps-arc@lists.infradead.org
Signed-off-by: Vineet Gupta <vgupta@kernel.org>
Remove the arc implemenation of strncpy/strnlen and instead use the
generic versions. The arc version is fairly slow because it always does
byte accesses even for aligned data, and its checks for user_addr_max()
differ from the generic code.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
DISCONTIGMEM was replaced by FLATMEM with freeing of the unused memory map
in v5.11.
Remove the support for DISCONTIGMEM entirely.
Link: https://lkml.kernel.org/r/20210608091316.3622-4-rppt@kernel.org
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Richard Henderson <rth@twiddle.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Arc does not use DISCONTIGMEM to implement high memory, update the comment
describing how high memory works to reflect this.
Link: https://lkml.kernel.org/r/20210608091316.3622-3-rppt@kernel.org
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Richard Henderson <rth@twiddle.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commit 4af22ded0e ("arc: fix memory initialization for systems
with two memory banks") fixed highmem, but for the PAE case it causes
bug messages:
| BUG: Bad page state in process swapper pfn:80000
| page:(ptrval) refcount:0 mapcount:1 mapping:00000000 index:0x0 pfn:0x80000 flags: 0x0()
| raw: 00000000 00000100 00000122 00000000 00000000 00000000 00000000 00000000
| raw: 00000000
| page dumped because: nonzero mapcount
| Modules linked in:
| CPU: 0 PID: 0 Comm: swapper Not tainted 5.12.0-rc5-00003-g1e43c377a79f #1
This is because the fix expects highmem to be always less than
lowmem and uses min_low_pfn as an upper zone border for highmem.
max_high_pfn should be ok for both highmem and highmem+PAE cases.
Fixes: 4af22ded0e ("arc: fix memory initialization for systems with two memory banks")
Signed-off-by: Vladimir Isaev <isaev@synopsys.com>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: stable@vger.kernel.org #5.8 onwards
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
32-bit PAGE_MASK can not be used as a mask for physical addresses
when PAE is enabled. PAGE_MASK_PHYS must be used for physical
addresses instead of PAGE_MASK.
Without this, init gets SIGSEGV if pte_modify was called:
| potentially unexpected fatal signal 11.
| Path: /bin/busybox
| CPU: 0 PID: 1 Comm: init Not tainted 5.12.0-rc5-00003-g1e43c377a79f-dirty
| Insn could not be fetched
| @No matching VMA found
| ECR: 0x00040000 EFA: 0x00000000 ERET: 0x00000000
| STAT: 0x80080082 [IE U ] BTA: 0x00000000
| SP: 0x5f9ffe44 FP: 0x00000000 BLK: 0xaf3d4
| LPS: 0x000d093e LPE: 0x000d0950 LPC: 0x00000000
| r00: 0x00000002 r01: 0x5f9fff14 r02: 0x5f9fff20
| ...
| Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b
Signed-off-by: Vladimir Isaev <isaev@synopsys.com>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: stable@vger.kernel.org
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
mem_init_print_info() is called in mem_init() on each architecture, and
pass NULL argument, so using void argument and move it into mm_init().
Link: https://lkml.kernel.org/r/20210317015210.33641-1-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com> [x86]
Reviewed-by: Christophe Leroy <christophe.leroy@c-s.fr> [powerpc]
Acked-by: David Hildenbrand <david@redhat.com>
Tested-by: Anatoly Pugachev <matorola@gmail.com> [sparc64]
Acked-by: Russell King <rmk+kernel@armlinux.org.uk> [arm]
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Guo Ren <guoren@kernel.org>
Cc: Yoshinori Sato <ysato@users.osdn.me>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "Peter Zijlstra" <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Merge misc updates from Andrew Morton:
- a few random little subsystems
- almost all of the MM patches which are staged ahead of linux-next
material. I'll trickle to post-linux-next work in as the dependents
get merged up.
Subsystems affected by this patch series: kthread, kbuild, ide, ntfs,
ocfs2, arch, and mm (slab-generic, slab, slub, dax, debug, pagecache,
gup, swap, shmem, memcg, pagemap, mremap, hmm, vmalloc, documentation,
kasan, pagealloc, memory-failure, hugetlb, vmscan, z3fold, compaction,
oom-kill, migration, cma, page-poison, userfaultfd, zswap, zsmalloc,
uaccess, zram, and cleanups).
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (200 commits)
mm: cleanup kstrto*() usage
mm: fix fall-through warnings for Clang
mm: slub: convert sysfs sprintf family to sysfs_emit/sysfs_emit_at
mm: shmem: convert shmem_enabled_show to use sysfs_emit_at
mm:backing-dev: use sysfs_emit in macro defining functions
mm: huge_memory: convert remaining use of sprintf to sysfs_emit and neatening
mm: use sysfs_emit for struct kobject * uses
mm: fix kernel-doc markups
zram: break the strict dependency from lzo
zram: add stat to gather incompressible pages since zram set up
zram: support page writeback
mm/process_vm_access: remove redundant initialization of iov_r
mm/zsmalloc.c: rework the list_add code in insert_zspage()
mm/zswap: move to use crypto_acomp API for hardware acceleration
mm/zswap: fix passing zero to 'PTR_ERR' warning
mm/zswap: make struct kernel_param_ops definitions const
userfaultfd/selftests: hint the test runner on required privilege
userfaultfd/selftests: fix retval check for userfaultfd_open()
userfaultfd/selftests: always dump something in modes
userfaultfd: selftests: make __{s,u}64 format specifiers portable
...
Currently ARC uses DISCONTIGMEM to cope with sparse physical memory address
space on systems with 2 memory banks. While DISCONTIGMEM avoids wasting
memory on unpopulated memory map, it adds both memory and CPU overhead
relatively to FLATMEM. Moreover, DISCONTINGMEM is generally considered
deprecated.
The obvious replacement for DISCONTIGMEM would be SPARSEMEM, but it is also
less efficient than FLATMEM in pfn_to_page() and page_to_pfn() conversions.
Besides it requires tuning of SECTION_SIZE which is not trivial for
possible ARC memory configuration.
Since the memory map for both banks is always allocated from the "lowmem"
bank, it is possible to use FLATMEM for two-bank configuration and simply
free the unused hole in the memory map. All is required for that is to
provide ARC-specific pfn_valid() that will take into account actual
physical memory configuration and define HAVE_ARCH_PFN_VALID.
The resulting kernel image configured with defconfig + HIGHMEM=y is
smaller:
$ size a/vmlinux b/vmlinux
text data bss dec hex filename
4673503 1245456 279756 6198715 5e95bb a/vmlinux
4658706 1246864 279756 6185326 5e616e b/vmlinux
$ ./scripts/bloat-o-meter a/vmlinux b/vmlinux
add/remove: 28/30 grow/shrink: 42/399 up/down: 10986/-29025 (-18039)
...
Total: Before=4709315, After = 4691276, chg -0.38%
Booting nSIM with haps_ns.dts results in the following memory usage
reports:
a:
Memory: 1559104K/1572864K available (3531K kernel code, 595K rwdata, 752K rodata, 136K init, 275K bss, 13760K reserved, 0K cma-reserved, 1048576K highmem)
b:
Memory: 1559112K/1572864K available (3519K kernel code, 594K rwdata, 752K rodata, 136K init, 280K bss, 13752K reserved, 0K cma-reserved, 1048576K highmem)
Link: https://lkml.kernel.org/r/20201101170454.9567-11-rppt@kernel.org
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Meelis Roos <mroos@linux.ee>
Cc: Michael Schmitz <schmitzmic@gmail.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- Consolidate all kmap_atomic() internals into a generic implementation
which builds the base for the kmap_local() API and make the
kmap_atomic() interface wrappers which handle the disabling/enabling of
preemption and pagefaults.
- Switch the storage from per-CPU to per task and provide scheduler
support for clearing mapping when scheduling out and restoring them
when scheduling back in.
- Merge the migrate_disable/enable() code, which is also part of the
scheduler pull request. This was required to make the kmap_local()
interface available which does not disable preemption when a mapping
is established. It has to disable migration instead to guarantee that
the virtual address of the mapped slot is the same accross preemption.
- Provide better debug facilities: guard pages and enforced utilization
of the mapping mechanics on 64bit systems when the architecture allows
it.
- Provide the new kmap_local() API which can now be used to cleanup the
kmap_atomic() usage sites all over the place. Most of the usage sites
do not require the implicit disabling of preemption and pagefaults so
the penalty on 64bit and 32bit non-highmem systems is removed and quite
some of the code can be simplified. A wholesale conversion is not
possible because some usage depends on the implicit side effects and
some need to be cleaned up because they work around these side effects.
The migrate disable side effect is only effective on highmem systems
and when enforced debugging is enabled. On 64bit and 32bit non-highmem
systems the overhead is completely avoided.
-----BEGIN PGP SIGNATURE-----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=n71I
-----END PGP SIGNATURE-----
Merge tag 'core-mm-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull kmap updates from Thomas Gleixner:
"The new preemtible kmap_local() implementation:
- Consolidate all kmap_atomic() internals into a generic
implementation which builds the base for the kmap_local() API and
make the kmap_atomic() interface wrappers which handle the
disabling/enabling of preemption and pagefaults.
- Switch the storage from per-CPU to per task and provide scheduler
support for clearing mapping when scheduling out and restoring them
when scheduling back in.
- Merge the migrate_disable/enable() code, which is also part of the
scheduler pull request. This was required to make the kmap_local()
interface available which does not disable preemption when a
mapping is established. It has to disable migration instead to
guarantee that the virtual address of the mapped slot is the same
across preemption.
- Provide better debug facilities: guard pages and enforced
utilization of the mapping mechanics on 64bit systems when the
architecture allows it.
- Provide the new kmap_local() API which can now be used to cleanup
the kmap_atomic() usage sites all over the place. Most of the usage
sites do not require the implicit disabling of preemption and
pagefaults so the penalty on 64bit and 32bit non-highmem systems is
removed and quite some of the code can be simplified. A wholesale
conversion is not possible because some usage depends on the
implicit side effects and some need to be cleaned up because they
work around these side effects.
The migrate disable side effect is only effective on highmem
systems and when enforced debugging is enabled. On 64bit and 32bit
non-highmem systems the overhead is completely avoided"
* tag 'core-mm-2020-12-14' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (33 commits)
ARM: highmem: Fix cache_is_vivt() reference
x86/crashdump/32: Simplify copy_oldmem_page()
io-mapping: Provide iomap_local variant
mm/highmem: Provide kmap_local*
sched: highmem: Store local kmaps in task struct
x86: Support kmap_local() forced debugging
mm/highmem: Provide CONFIG_DEBUG_KMAP_LOCAL_FORCE_MAP
mm/highmem: Provide and use CONFIG_DEBUG_KMAP_LOCAL
microblaze/mm/highmem: Add dropped #ifdef back
xtensa/mm/highmem: Make generic kmap_atomic() work correctly
mm/highmem: Take kmap_high_get() properly into account
highmem: High implementation details and document API
Documentation/io-mapping: Remove outdated blurb
io-mapping: Cleanup atomic iomap
mm/highmem: Remove the old kmap_atomic cruft
highmem: Get rid of kmap_types.h
xtensa/mm/highmem: Switch to generic kmap atomic
sparc/mm/highmem: Switch to generic kmap atomic
powerpc/mm/highmem: Switch to generic kmap atomic
nds32/mm/highmem: Switch to generic kmap atomic
...
Adopt the map ordering to match the other architectures and the generic
code. Also make the maximum entries limited and not dependend on the number
of CPUs. With the original implementation did the following calculation:
nr_slots = mapsize >> PAGE_SHIFT;
The results in either 512 or 1024 total slots depending on
configuration. The total slots have to be divided by the number of CPUs to
get the number of slots per CPU (former KM_TYPE_NR). ARC supports up to 4k
CPUs, so this just falls apart in random ways depending on the number of
CPUs and the actual kmap (atomic) nesting. The comment in highmem.c:
* - fixmap anyhow needs a limited number of mappings. So 2M kvaddr == 256 PTE
* slots across NR_CPUS would be more than sufficient (generic code defines
* KM_TYPE_NR as 20).
is just wrong. KM_TYPE_NR (now KM_MAX_IDX) is the number of slots per CPU
because kmap_local/atomic() needs to support nested mappings (thread,
softirq, interrupt). While KM_MAX_IDX might be overestimated, the above
reasoning is just wrong and clearly the highmem code was never tested with
any system with more than a few CPUs.
Use the default number of slots and fail the build when it does not
fit. Randomly failing at runtime is not a really good option.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20201103095857.472289952@linutronix.de
