Pull OpenRISC updates from Stafford Horne:
"A few patches all over the place during this cycle, mostly bug and
sparse warning fixes for OpenRISC, but a few enhancements too. Note,
there are 2 non OpenRISC specific fixups.
Non OpenRISC fixes:
- In init we need to align the init_task correctly to fix an issue
with MUTEX_FLAGS, reviewed by Peter Z. No one picked this up so I
kept it on my tree.
- In asm-generic/io.h I fixed up some sparse warnings, OK'd by Arnd.
Arnd asked to merge it via my tree.
OpenRISC fixes:
- Many fixes for OpenRISC sprase warnings.
- Add support OpenRISC SMP tlb flushing rather than always flushing
the entire TLB on every CPU.
- Fix bug when dumping stack via /proc/xxx/stack of user threads"
* tag 'for-linus' of git://github.com/openrisc/linux:
openrisc: uaccess: Add user address space check to access_ok
openrisc: signal: Fix sparse address space warnings
openrisc: uaccess: Remove unused macro __addr_ok
openrisc: uaccess: Use static inline function in access_ok
openrisc: uaccess: Fix sparse address space warnings
openrisc: io: Fixup defines and move include to the end
asm-generic/io.h: Fix sparse warnings on big-endian architectures
openrisc: Implement proper SMP tlb flushing
openrisc: Fix oops caused when dumping stack
openrisc: Add support for external initrd images
init: Align init_task to avoid conflict with MUTEX_FLAGS
openrisc: fix __user in raw_copy_to_user()'s prototype
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
Now that __user annotations are fixed for openrisc uaccess api's we can
add checking to the access_ok macro. This patch adds the __chk_user_ptr
check, on normal builds the added check is a nop.
Signed-off-by: Stafford Horne <shorne@gmail.com>
Reviewed-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Since commit b48b2c3e50 ("openrisc: use generic strnlen_user()
function") the macro __addr_ok is no longer used. It is safe to remove
so this patch removes it.
Signed-off-by: Stafford Horne <shorne@gmail.com>
As suggested by Linus when reviewing commit 9cb2feb4d2
("arch/openrisc: Fix issues with access_ok()") last year; making
__range_ok an inline function also fixes the used twice issue that the
commit was fixing. I agree it's a good cleanup. This patch addresses
that as I am currently working on the access_ok macro to fixup sparse
annotations in OpenRISC.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Stafford Horne <shorne@gmail.com>
Reviewed-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
The OpenRISC user access functions put_user(), get_user() and
clear_user() were missing proper sparse annotations. This generated
warnings like the below.
This patch adds the annotations to fix the warnings.
Example warnings:
net/ipv4/ip_sockglue.c:759:29: warning: incorrect type in argument 1 (different address spaces)
net/ipv4/ip_sockglue.c:759:29: expected void const volatile [noderef] __user *
net/ipv4/ip_sockglue.c:759:29: got int const *__gu_addr
net/ipv4/ip_sockglue.c:764:29: warning: incorrect type in initializer (different address spaces)
net/ipv4/ip_sockglue.c:764:29: expected unsigned char const *__gu_addr
net/ipv4/ip_sockglue.c:764:29: got unsigned char [noderef] __user *
Signed-off-by: Stafford Horne <shorne@gmail.com>
Reviewed-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Merge misc updates from Andrew Morton:
- a few MM hotfixes
- kthread, tools, scripts, ntfs and ocfs2
- some of MM
Subsystems affected by this patch series: kthread, tools, scripts, ntfs,
ocfs2 and mm (hofixes, pagealloc, slab-generic, slab, slub, kcsan,
debug, pagecache, gup, swap, shmem, memcg, pagemap, mremap, mincore,
sparsemem, vmalloc, kasan, pagealloc, hugetlb and vmscan).
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (162 commits)
mm: vmscan: consistent update to pgrefill
mm/vmscan.c: fix typo
khugepaged: khugepaged_test_exit() check mmget_still_valid()
khugepaged: retract_page_tables() remember to test exit
khugepaged: collapse_pte_mapped_thp() protect the pmd lock
khugepaged: collapse_pte_mapped_thp() flush the right range
mm/hugetlb: fix calculation of adjust_range_if_pmd_sharing_possible
mm: thp: replace HTTP links with HTTPS ones
mm/page_alloc: fix memalloc_nocma_{save/restore} APIs
mm/page_alloc.c: skip setting nodemask when we are in interrupt
mm/page_alloc: fallbacks at most has 3 elements
mm/page_alloc: silence a KASAN false positive
mm/page_alloc.c: remove unnecessary end_bitidx for [set|get]_pfnblock_flags_mask()
mm/page_alloc.c: simplify pageblock bitmap access
mm/page_alloc.c: extract the common part in pfn_to_bitidx()
mm/page_alloc.c: replace the definition of NR_MIGRATETYPE_BITS with PB_migratetype_bits
mm/shuffle: remove dynamic reconfiguration
mm/memory_hotplug: document why shuffle_zone() is relevant
mm/page_alloc: remove nr_free_pagecache_pages()
mm: remove vm_total_pages
...
Patch series "mm: cleanup usage of <asm/pgalloc.h>"
Most architectures have very similar versions of pXd_alloc_one() and
pXd_free_one() for intermediate levels of page table. These patches add
generic versions of these functions in <asm-generic/pgalloc.h> and enable
use of the generic functions where appropriate.
In addition, functions declared and defined in <asm/pgalloc.h> headers are
used mostly by core mm and early mm initialization in arch and there is no
actual reason to have the <asm/pgalloc.h> included all over the place.
The first patch in this series removes unneeded includes of
<asm/pgalloc.h>
In the end it didn't work out as neatly as I hoped and moving
pXd_alloc_track() definitions to <asm-generic/pgalloc.h> would require
unnecessary changes to arches that have custom page table allocations, so
I've decided to move lib/ioremap.c to mm/ and make pgalloc-track.h local
to mm/.
This patch (of 8):
In most cases <asm/pgalloc.h> header is required only for allocations of
page table memory. Most of the .c files that include that header do not
use symbols declared in <asm/pgalloc.h> and do not require that header.
As for the other header files that used to include <asm/pgalloc.h>, it is
possible to move that include into the .c file that actually uses symbols
from <asm/pgalloc.h> and drop the include from the header file.
The process was somewhat automated using
sed -i -E '/[<"]asm\/pgalloc\.h/d' \
$(grep -L -w -f /tmp/xx \
$(git grep -E -l '[<"]asm/pgalloc\.h'))
where /tmp/xx contains all the symbols defined in
arch/*/include/asm/pgalloc.h.
[rppt@linux.ibm.com: fix powerpc warning]
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Pekka Enberg <penberg@kernel.org>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> [m68k]
Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Joerg Roedel <joro@8bytes.org>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Satheesh Rajendran <sathnaga@linux.vnet.ibm.com>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Joerg Roedel <jroedel@suse.de>
Cc: Matthew Wilcox <willy@infradead.org>
Link: http://lkml.kernel.org/r/20200627143453.31835-1-rppt@kernel.org
Link: http://lkml.kernel.org/r/20200627143453.31835-2-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull ptrace regset updates from Al Viro:
"Internal regset API changes:
- regularize copy_regset_{to,from}_user() callers
- switch to saner calling conventions for ->get()
- kill user_regset_copyout()
The ->put() side of things will have to wait for the next cycle,
unfortunately.
The balance is about -1KLoC and replacements for ->get() instances are
a lot saner"
* 'work.regset' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (41 commits)
regset: kill user_regset_copyout{,_zero}()
regset(): kill ->get_size()
regset: kill ->get()
csky: switch to ->regset_get()
xtensa: switch to ->regset_get()
parisc: switch to ->regset_get()
nds32: switch to ->regset_get()
nios2: switch to ->regset_get()
hexagon: switch to ->regset_get()
h8300: switch to ->regset_get()
openrisc: switch to ->regset_get()
riscv: switch to ->regset_get()
c6x: switch to ->regset_get()
ia64: switch to ->regset_get()
arc: switch to ->regset_get()
arm: switch to ->regset_get()
sh: convert to ->regset_get()
arm64: switch to ->regset_get()
mips: switch to ->regset_get()
sparc: switch to ->regset_get()
...
This didn't seem to cause any issues, but while working on fixing up
sparse annotations for OpenRISC I noticed this. This patch moves the
include of asm-generic/io.h to the end of the file. Also, we add
defines of ioremap and iounmap, that way we don't get duplicate
definitions from asm-generic/io.h.
Signed-off-by: Stafford Horne <shorne@gmail.com>
Pull fork cleanups from Christian Brauner:
"This is cleanup series from when we reworked a chunk of the process
creation paths in the kernel and switched to struct
{kernel_}clone_args.
High-level this does two main things:
- Remove the double export of both do_fork() and _do_fork() where
do_fork() used the incosistent legacy clone calling convention.
Now we only export _do_fork() which is based on struct
kernel_clone_args.
- Remove the copy_thread_tls()/copy_thread() split making the
architecture specific HAVE_COYP_THREAD_TLS config option obsolete.
This switches all remaining architectures to select
HAVE_COPY_THREAD_TLS and thus to the copy_thread_tls() calling
convention. The current split makes the process creation codepaths
more convoluted than they need to be. Each architecture has their own
copy_thread() function unless it selects HAVE_COPY_THREAD_TLS then it
has a copy_thread_tls() function.
The split is not needed anymore nowadays, all architectures support
CLONE_SETTLS but quite a few of them never bothered to select
HAVE_COPY_THREAD_TLS and instead simply continued to use copy_thread()
and use the old calling convention. Removing this split cleans up the
process creation codepaths and paves the way for implementing clone3()
on such architectures since it requires the copy_thread_tls() calling
convention.
After having made each architectures support copy_thread_tls() this
series simply renames that function back to copy_thread(). It also
switches all architectures that call do_fork() directly over to
_do_fork() and the struct kernel_clone_args calling convention. This
is a corollary of switching the architectures that did not yet support
it over to copy_thread_tls() since do_fork() is conditional on not
supporting copy_thread_tls() (Mostly because it lacks a separate
argument for tls which is trivial to fix but there's no need for this
function to exist.).
The do_fork() removal is in itself already useful as it allows to to
remove the export of both do_fork() and _do_fork() we currently have
in favor of only _do_fork(). This has already been discussed back when
we added clone3(). The legacy clone() calling convention is - as is
probably well-known - somewhat odd:
#
# ABI hall of shame
#
config CLONE_BACKWARDS
config CLONE_BACKWARDS2
config CLONE_BACKWARDS3
that is aggravated by the fact that some architectures such as sparc
follow the CLONE_BACKWARDSx calling convention but don't really select
the corresponding config option since they call do_fork() directly.
So do_fork() enforces a somewhat arbitrary calling convention in the
first place that doesn't really help the individual architectures that
deviate from it. They can thus simply be switched to _do_fork()
enforcing a single calling convention. (I really hope that any new
architectures will __not__ try to implement their own calling
conventions...)
Most architectures already have made a similar switch (m68k comes to
mind).
Overall this removes more code than it adds even with a good portion
of added comments. It simplifies a chunk of arch specific assembly
either by moving the code into C or by simply rewriting the assembly.
Architectures that have been touched in non-trivial ways have all been
actually boot and stress tested: sparc and ia64 have been tested with
Debian 9 images. They are the two architectures which have been
touched the most. All non-trivial changes to architectures have seen
acks from the relevant maintainers. nios2 with a custom built
buildroot image. h8300 I couldn't get something bootable to test on
but the changes have been fairly automatic and I'm sure we'll hear
people yell if I broke something there.
All other architectures that have been touched in trivial ways have
been compile tested for each single patch of the series via git rebase
-x "make ..." v5.8-rc2. arm{64} and x86{_64} have been boot tested
even though they have just been trivially touched (removal of the
HAVE_COPY_THREAD_TLS macro from their Kconfig) because well they are
basically "core architectures" and since it is trivial to get your
hands on a useable image"
* tag 'fork-v5.9' of git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux:
arch: rename copy_thread_tls() back to copy_thread()
arch: remove HAVE_COPY_THREAD_TLS
unicore: switch to copy_thread_tls()
sh: switch to copy_thread_tls()
nds32: switch to copy_thread_tls()
microblaze: switch to copy_thread_tls()
hexagon: switch to copy_thread_tls()
c6x: switch to copy_thread_tls()
alpha: switch to copy_thread_tls()
fork: remove do_fork()
h8300: select HAVE_COPY_THREAD_TLS, switch to kernel_clone_args
nios2: enable HAVE_COPY_THREAD_TLS, switch to kernel_clone_args
ia64: enable HAVE_COPY_THREAD_TLS, switch to kernel_clone_args
sparc: unconditionally enable HAVE_COPY_THREAD_TLS
sparc: share process creation helpers between sparc and sparc64
sparc64: enable HAVE_COPY_THREAD_TLS
fork: fold legacy_clone_args_valid() into _do_fork()
Up until now when flushing pages from the TLB on SMP OpenRISC was always
resorting to flush the entire TLB on all CPUs. This patch adds the
mechanics for flushing specific ranges and pages based on the usage.
The function switch_mm is updated to account for cpu usage by updating
mm_struct's cpumask. This is used in the SMP flush routines.
This mostly follows the riscv implementation.
Signed-off-by: Stafford Horne <shorne@gmail.com>
When dumping a stack with 'cat /proc/#/stack' the kernel would oops.
For example:
# cat /proc/690/stack
Unable to handle kernel access
at virtual address 0x7fc60f58
Oops#: 0000
CPU #: 0
PC: c00097fc SR: 0000807f SP: d6f09b9c
GPR00: 00000000 GPR01: d6f09b9c GPR02: d6f09bb8 GPR03: d6f09bc4
GPR04: 7fc60f5c GPR05: c00099b4 GPR06: 00000000 GPR07: d6f09ba3
GPR08: ffffff00 GPR09: c0009804 GPR10: d6f08000 GPR11: 00000000
GPR12: ffffe000 GPR13: dbb86000 GPR14: 00000001 GPR15: dbb86250
GPR16: 7fc60f63 GPR17: 00000f5c GPR18: d6f09bc4 GPR19: 00000000
GPR20: c00099b4 GPR21: ffffffc0 GPR22: 00000000 GPR23: 00000000
GPR24: 00000001 GPR25: 000002c6 GPR26: d78b6850 GPR27: 00000001
GPR28: 00000000 GPR29: dbb86000 GPR30: ffffffff GPR31: dbb862fc
RES: 00000000 oGPR11: ffffffff
Process cat (pid: 702, stackpage=d79d6000)
Stack:
Call trace:
[<598977f2>] save_stack_trace_tsk+0x40/0x74
[<95063f0e>] stack_trace_save_tsk+0x44/0x58
[<b557bfdd>] proc_pid_stack+0xd0/0x13c
[<a2df8eda>] proc_single_show+0x6c/0xf0
[<e5a737b7>] seq_read+0x1b4/0x688
[<2d6c7480>] do_iter_read+0x208/0x248
[<2182a2fb>] vfs_readv+0x64/0x90
This was caused by the stack trace code in save_stack_trace_tsk using
the wrong stack pointer. It was using the user stack pointer instead of
the kernel stack pointer. Fix this by using the right stack.
Also for good measure we add try_get_task_stack/put_task_stack to ensure
the task is not lost while we are walking it's stack.
Fixes: eecac38b04 ("openrisc: support framepointers and STACKTRACE_SUPPORT")
Signed-off-by: Stafford Horne <shorne@gmail.com>
In OpenRISC we set the initrd_start and initrd_end based on the symbols
we setup in vmlinux.lds.S. However, this is not needed if we use the
generic linker description in INIT_DATA_SECTION.
Removing our own initrd setup reduces code, but also the generic code
supports loading external initrd images. A bootloader can load a rootfs
image into memory and we can configure devicetree to load it with:
chosen {
bootargs = "earlycon";
stdout-path = "uart0:115200";
linux,initrd-start = < 0x08000100 >;
linux,initrd-end = < 0x08200000 >;
};
Reported-by: Mateusz Holenko <mholenko@antmicro.com>
Signed-off-by: Stafford Horne <shorne@gmail.com>
raw_copy_to_user()'s prototype seems to be a copy & paste of
raw_copy_from_user() and as such has the __user annotation
in the 'from' argument instead of the 'to'.
So, move the __user annotation in the prototype to the 'to'.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Signed-off-by: Stafford Horne <shorne@gmail.com>
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>
All architectures support copy_thread_tls() now, so remove the legacy
copy_thread() function and the HAVE_COPY_THREAD_TLS config option. Everyone
uses the same process creation calling convention based on
copy_thread_tls() and struct kernel_clone_args. This will make it easier to
maintain the core process creation code under kernel/, simplifies the
callpaths and makes the identical for all architectures.
Cc: linux-arch@vger.kernel.org
Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Acked-by: Greentime Hu <green.hu@gmail.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Pull OpenRISC update from Stafford Horne:
"One patch found wile I was getting the glibc port ready: fix issue
with clone TLS arg getting overwritten"
* tag 'for-linus' of git://github.com/openrisc/linux:
openrisc: Fix issue with argument clobbering for clone/fork
Currently, the log-level of show_stack() depends on a platform
realization. It creates situations where the headers are printed with
lower log level or higher than the stacktrace (depending on a platform or
user).
Furthermore, it forces the logic decision from user to an architecture
side. In result, some users as sysrq/kdb/etc are doing tricks with
temporary rising console_loglevel while printing their messages. And in
result it not only may print unwanted messages from other CPUs, but also
omit printing at all in the unlucky case where the printk() was deferred.
Introducing log-level parameter and KERN_UNSUPPRESSED [1] seems an easier
approach than introducing more printk buffers. Also, it will consolidate
printings with headers.
Introduce show_stack_loglvl(), that eventually will substitute
show_stack().
[1]: https://lore.kernel.org/lkml/20190528002412.1625-1-dima@arista.com/T/#u
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
Link: http://lkml.kernel.org/r/20200418201944.482088-25-dima@arista.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Working on the OpenRISC glibc port I found that sometimes clone was
working strange. That the tls data argument sent in r7 was always
wrong. Further investigation revealed that the arguments were getting
clobbered in the entry code. This patch removes the code that writes to
the argument registers. This was likely due to some old code hanging
around.
This patch fixes this up for clone and fork. This fork clobber is
harmless but also useless so remove.
Signed-off-by: Stafford Horne <shorne@gmail.com>
Pull OpenRISC updates from Stafford Horne:
"A few cleanups all over the place, things of note:
- Enable the clone3 syscall
- Remove CONFIG_CROSS_COMPILE from Krzysztof Kozlowski
- Update to use mmgrab from Julia Lawall"
* tag 'for-linus' of git://github.com/openrisc/linux:
openrisc: Remove obsolete show_trace_task function
openrisc: Cleanup copy_thread_tls docs and comments
openrisc: Enable the clone3 syscall
openrisc: Convert copy_thread to copy_thread_tls
openrisc: use mmgrab
openrisc: configs: Cleanup CONFIG_CROSS_COMPILE
Pull dma-mapping updates from Christoph Hellwig:
- fix an integer overflow in the coherent pool (Kevin Grandemange)
- provide support for in-place uncached remapping and use that for
openrisc
- fix the arm coherent allocator to take the bus limit into account
* tag 'dma-mapping-5.7' of git://git.infradead.org/users/hch/dma-mapping:
ARM/dma-mapping: merge __dma_supported into arm_dma_supported
ARM/dma-mapping: take the bus limit into account in __dma_alloc
ARM/dma-mapping: remove get_coherent_dma_mask
openrisc: use the generic in-place uncached DMA allocator
dma-direct: provide a arch_dma_clear_uncached hook
dma-direct: make uncached_kernel_address more general
dma-direct: consolidate the error handling in dma_direct_alloc_pages
dma-direct: remove the cached_kernel_address hook
dma-coherent: fix integer overflow in the reserved-memory dma allocation
Pull SPDX updates from Greg KH:
"Here are three SPDX patches for 5.7-rc1.
One fixes up the SPDX tag for a single driver, while the other two go
through the tree and add SPDX tags for all of the .gitignore files as
needed.
Nothing too complex, but you will get a merge conflict with your
current tree, that should be trivial to handle (one file modified by
two things, one file deleted.)
All three of these have been in linux-next for a while, with no
reported issues other than the merge conflict"
* tag 'spdx-5.7-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/spdx:
ASoC: MT6660: make spdxcheck.py happy
.gitignore: add SPDX License Identifier
.gitignore: remove too obvious comments
The idea comes from a discussion between Linus and Andrea [1].
Before this patch we only allow a page fault to retry once. We achieved
this by clearing the FAULT_FLAG_ALLOW_RETRY flag when doing
handle_mm_fault() the second time. This was majorly used to avoid
unexpected starvation of the system by looping over forever to handle the
page fault on a single page. However that should hardly happen, and after
all for each code path to return a VM_FAULT_RETRY we'll first wait for a
condition (during which time we should possibly yield the cpu) to happen
before VM_FAULT_RETRY is really returned.
This patch removes the restriction by keeping the FAULT_FLAG_ALLOW_RETRY
flag when we receive VM_FAULT_RETRY. It means that the page fault handler
now can retry the page fault for multiple times if necessary without the
need to generate another page fault event. Meanwhile we still keep the
FAULT_FLAG_TRIED flag so page fault handler can still identify whether a
page fault is the first attempt or not.
Then we'll have these combinations of fault flags (only considering
ALLOW_RETRY flag and TRIED flag):
- ALLOW_RETRY and !TRIED: this means the page fault allows to
retry, and this is the first try
- ALLOW_RETRY and TRIED: this means the page fault allows to
retry, and this is not the first try
- !ALLOW_RETRY and !TRIED: this means the page fault does not allow
to retry at all
- !ALLOW_RETRY and TRIED: this is forbidden and should never be used
In existing code we have multiple places that has taken special care of
the first condition above by checking against (fault_flags &
FAULT_FLAG_ALLOW_RETRY). This patch introduces a simple helper to detect
the first retry of a page fault by checking against both (fault_flags &
FAULT_FLAG_ALLOW_RETRY) and !(fault_flag & FAULT_FLAG_TRIED) because now
even the 2nd try will have the ALLOW_RETRY set, then use that helper in
all existing special paths. One example is in __lock_page_or_retry(), now
we'll drop the mmap_sem only in the first attempt of page fault and we'll
keep it in follow up retries, so old locking behavior will be retained.
This will be a nice enhancement for current code [2] at the same time a
supporting material for the future userfaultfd-writeprotect work, since in
that work there will always be an explicit userfault writeprotect retry
for protected pages, and if that cannot resolve the page fault (e.g., when
userfaultfd-writeprotect is used in conjunction with swapped pages) then
we'll possibly need a 3rd retry of the page fault. It might also benefit
other potential users who will have similar requirement like userfault
write-protection.
GUP code is not touched yet and will be covered in follow up patch.
Please read the thread below for more information.
[1] https://lore.kernel.org/lkml/20171102193644.GB22686@redhat.com/
[2] https://lore.kernel.org/lkml/20181230154648.GB9832@redhat.com/
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Suggested-by: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Brian Geffon <bgeffon@google.com>
Cc: Bobby Powers <bobbypowers@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Denis Plotnikov <dplotnikov@virtuozzo.com>
Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Martin Cracauer <cracauer@cons.org>
Cc: Marty McFadden <mcfadden8@llnl.gov>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Maya Gokhale <gokhale2@llnl.gov>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Link: http://lkml.kernel.org/r/20200220160246.9790-1-peterx@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change a header to mandatory-y if both of the following are met:
[1] At least one architecture (except um) specifies it as generic-y in
arch/*/include/asm/Kbuild
[2] Every architecture (except um) either has its own implementation
(arch/*/include/asm/*.h) or specifies it as generic-y in
arch/*/include/asm/Kbuild
This commit was generated by the following shell script.
----------------------------------->8-----------------------------------
arches=$(cd arch; ls -1 | sed -e '/Kconfig/d' -e '/um/d')
tmpfile=$(mktemp)
grep "^mandatory-y +=" include/asm-generic/Kbuild > $tmpfile
find arch -path 'arch/*/include/asm/Kbuild' |
xargs sed -n 's/^generic-y += \(.*\)/\1/p' | sort -u |
while read header
do
mandatory=yes
for arch in $arches
do
if ! grep -q "generic-y += $header" arch/$arch/include/asm/Kbuild &&
! [ -f arch/$arch/include/asm/$header ]; then
mandatory=no
break
fi
done
if [ "$mandatory" = yes ]; then
echo "mandatory-y += $header" >> $tmpfile
for arch in $arches
do
sed -i "/generic-y += $header/d" arch/$arch/include/asm/Kbuild
done
fi
done
sed -i '/^mandatory-y +=/d' include/asm-generic/Kbuild
LANG=C sort $tmpfile >> include/asm-generic/Kbuild
----------------------------------->8-----------------------------------
One obvious benefit is the diff stat:
25 files changed, 52 insertions(+), 557 deletions(-)
It is tedious to list generic-y for each arch that needs it.
So, mandatory-y works like a fallback default (by just wrapping
asm-generic one) when arch does not have a specific header
implementation.
See the following commits:
def3f7cefea1b39bae16
It is tedious to convert headers one by one, so I processed by a shell
script.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Link: http://lkml.kernel.org/r/20200210175452.5030-1-masahiroy@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Move access_ok() in and pagefault_enable()/pagefault_disable() out.
Mechanical conversion only - some instances don't really need
a separate access_ok() at all (e.g. the ones only using
get_user()/put_user(), or architectures where access_ok()
is always true); we'll deal with that in followups.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
