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With CONFIG_BUG=n, the 64-bit Book3S build fails with:
arch/powerpc/include/asm/book3s/64/pgtable-64k.h: In function 'get_hugepd_cache_index':
arch/powerpc/include/asm/book3s/64/pgtable-64k.h:51:1: error: no return statement in function returning non-void
Currently the body of the function is just BUG(), so when CONFIG_BUG=n
it is an empty function, leading to the error.
get_hugepd_cache_index() should never be called, the only call is behind
an is_hugepd() check, which is always false for this configuration.
Instead mark it as always inline, and change the BUG() to BUILD_BUG().
That should allow the compiler to see that the function is never called,
and therefore that it never returns, fixing the build error.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20240306125853.3714578-1-mpe@ellerman.id.au
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On powerpc there are two ways for huge pages to be represented in the
top level page table, aka PGD (Page Global Directory).
If the address space mapped by an individual PGD entry does not
correspond to a given huge page size, then the PGD entry points to a
non-standard page table, known as a "hugepd" (Huge Page Directory).
The hugepd contains some number of huge page PTEs sufficient to map the
address space with the given huge page size.
On the other hand, if the address space mapped by an individual PGD
entry does correspond exactly to a given huge page size, that PGD entry
is used to directly encode the huge page PTE in place. In this case the
pgd_huge() wrapper indicates to generic code that the PGD entry is
actually a huge page PTE.
This commit deals with the pgd_huge() case only, it does nothing with
respect to the hugepd case.
Over time the size of the virtual address space supported on powerpc has
increased several times, which means the location at which huge pages
can sit in the tree has also changed. There have also been new huge page
sizes added, with the introduction of the Radix MMU.
On Power9 and later with the Radix MMU, the largest huge page size in
any implementation is 1GB.
Since the introduction of Radix, 1GB entries have been supported at the
PUD level, with both 4K and 64K base page size. Radix has never had a
supported huge page size at the PGD level.
On Power8 or earlier, which uses the Hash MMU, or Power9 or later with
the Hash MMU enabled, the largest huge page size is 16GB.
Using the Hash MMU and a base page size of 4K, 16GB has never been a
supported huge page size at the PGD level, due to the geometry being
incompatible. The two supported huge page sizes (16M & 16GB) both use
the hugepd format.
Using the Hash MMU and a base page size of 64K, 16GB pages were
supported in the past at the PGD level.
However in commit ba95b5d03596 ("powerpc/mm/book3s/64: Rework page table
geometry for lower memory usage") the page table layout was reworked to
shrink the size of the PGD.
As a result the 16GB page size now fits at the PUD level when using 64K
base page size.
Therefore there are no longer any supported configurations where
pgd_huge() can be true, so drop the definitions for pgd_huge(), and
fallback to the generic definition which is always false.
Fixes: ba95b5d03596 ("powerpc/mm/book3s/64: Rework page table geometry for lower memory usage")
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20220903123640.719846-1-mpe@ellerman.id.au
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Patch series "hugetlbfs: convert macros to static inline, fix sparse
warning".
The definition for huge_pte_offset() in <linux/hugetlb.h> causes a
sparse warning in the !CONFIG_HUGETLB_PAGE. Fix this as well as
converting all macros in this block of definitions to static inlines for
better type checking.
When making the above changes, build errors were found in powerpc due to
duplicate definitions. A separate powerpc specific patch is included as
a requisite to remove the definitions and get them from
<linux/hugetlb.h>.
This patch (of 2):
This removes the power specific stubs created by commit aad71e3928be
("powerpc/mm: Fix build break with RADIX=y & HUGETLBFS=n") used when
!CONFIG_HUGETLB_PAGE. Instead, it addresses the build break by getting
the definitions from <linux/hugetlb.h>. This allows the macros in
<linux/hugetlb.h> to be replaced with static inlines.
Link: http://lkml.kernel.org/r/20191112194558.139389-2-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Cc: Ben Dooks <ben.dooks@codethink.co.uk>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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We need to make sure pmd_trans_huge returns false for a pmd migration entry.
We mark the migration entry by clearing the _PAGE_PRESENT bit. We keep the
_PAGE_PTE bit set to indicate a leaf page table entry. Hence we need to make
sure we check for pmd_present() so that pmd_trans_huge won't return true on
pmd migration entry.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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With 4k page size for hugetlb we allocate hugepage directories from its on slab
cache. With patch 0c4d26802 ("powerpc/book3s64/mm: Simplify the rcu callback for page table free")
we missed to free these allocated hugepd tables.
Update pgtable_free to handle hugetlb hugepd directory table.
Fixes: 0c4d268029bf ("powerpc/book3s64/mm: Simplify the rcu callback for page table free")
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
[mpe: Add CONFIG_HUGETLB_PAGE guard to fix build break]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.
By default all files without license information are under the default
license of the kernel, which is GPL version 2.
Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.
This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.
How this work was done:
Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,
Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.
The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.
The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.
Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).
All documentation files were explicitly excluded.
The following heuristics were used to determine which SPDX license
identifiers to apply.
- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.
For non */uapi/* files that summary was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139
and resulted in the first patch in this series.
If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:
SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930
and resulted in the second patch in this series.
- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:
SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1
and that resulted in the third patch in this series.
- when the two scanners agreed on the detected license(s), that became
the concluded license(s).
- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.
- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).
- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.
- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.
In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.
Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.
Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.
In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.
Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct
This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.
These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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If we enable RADIX but disable HUGETLBFS, the build breaks with:
arch/powerpc/mm/pgtable-radix.c:557:7: error: implicit declaration of function 'pmd_huge'
arch/powerpc/mm/pgtable-radix.c:588:7: error: implicit declaration of function 'pud_huge'
Fix it by stubbing those functions when HUGETLBFS=n.
Fixes: 4b5d62ca17a1 ("powerpc/mm: add radix__remove_section_mapping()")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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We don't do this for other page table entries. So lets keep this simple
and always return false for hugepd check on a 64K page size config.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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This switch few of the page table accessor to use the __raw variant
and does the cpu to big endian conversion of constants. This helps in
generating better code.
For ex: a pgd_none(pgd) check with and without fix is listed below
Without fix:
------------
2240: 20 00 61 eb ld r27,32(r1)
/* PGD level */
typedef struct { __be64 pgd; } pgd_t;
static inline unsigned long pgd_val(pgd_t x)
{
return be64_to_cpu(x.pgd);
2244: 22 00 66 78 rldicl r6,r3,32,32
2248: 3e 40 7d 54 rotlwi r29,r3,8
224c: 0e c0 7d 50 rlwimi r29,r3,24,0,7
2250: 3e 40 c5 54 rotlwi r5,r6,8
2254: 2e c4 7d 50 rlwimi r29,r3,24,16,23
2258: 0e c0 c5 50 rlwimi r5,r6,24,0,7
225c: 2e c4 c5 50 rlwimi r5,r6,24,16,23
2260: c6 07 bd 7b rldicr r29,r29,32,31
2264: 78 2b bd 7f or r29,r29,r5
if (pgd_none(pgd))
2268: 00 00 bd 2f cmpdi cr7,r29,0
226c: 54 03 9e 41 beq cr7,25c0 <__get_user_pages_fast+0x500>
With fix:
---------
2370: 20 00 61 eb ld r27,32(r1)
if (pgd_none(pgd))
2374: 00 00 bd 2f cmpdi cr7,r29,0
2378: a8 03 9e 41 beq cr7,2720 <__get_user_pages_fast+0x530>
break;
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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This adds THP support for 4K Linux page size config with radix. We still
don't do THP with 4K Linux page size and hash page table. Hash page
table needs a 16MB hugepage and we can't do THP with 16MM hugepage and
4K Linux page size.
We add missing functions to 4K hash config to get it to build and
hash__has_transparent_hugepage() makes sure we don't enable THP for 4K
hash config. To catch wrong usage of THP related with 4K config, we add
BUG() in those dummy functions we added to get it compile.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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The deposited pgtable_t is a pte fragment hence we cannot use page->lru
for linking then together. We use the first two 64 bits for pte fragment
as list_head type to link all deposited fragments together. On withdraw
we properly zero then out.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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This only does 64K Linux page support for now. 64K hash Linux config
THP needs to differentiate it from hugetlb huge page because with THP we
need to track hash pte slot information with respect to each subpage.
This is not needed with hugetlb hugepage, because we don't do MPSS with
hugetlb.
Radix doesn't have any such restrictions.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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Here we create pgtable-64/4k.h and move pmd accessors that are common
between hash and radix there. We can't do much sharing with 4K Linux
page size because 4K Linux page size with hash config doesn't support
THP. So for now it is empty. In later patches we will add functions that
does conditional hash/radix accessors there.
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
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Michael Ellerman
Mike Kravetz
Aneesh Kumar K.V
Greg Kroah-Hartman
Aneesh Kumar K.V