#
d8b0f546 |
| 25-Oct-2023 |
Miklos Szeredi <mszeredi@redhat.com> |
wire up syscalls for statmount/listmount
Wire up all archs.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Link: https://lore.kernel.org/r/20231025140205.3586473-7-mszeredi@redhat.com Reviewed
wire up syscalls for statmount/listmount
Wire up all archs.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com> Link: https://lore.kernel.org/r/20231025140205.3586473-7-mszeredi@redhat.com Reviewed-by: Ian Kent <raven@themaw.net> Signed-off-by: Christian Brauner <brauner@kernel.org>
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5f423759 |
| 12-Sep-2023 |
Casey Schaufler <casey@schaufler-ca.com> |
LSM: wireup Linux Security Module syscalls
Wireup lsm_get_self_attr, lsm_set_self_attr and lsm_list_modules system calls.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Kees C
LSM: wireup Linux Security Module syscalls
Wireup lsm_get_self_attr, lsm_set_self_attr and lsm_list_modules system calls.
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com> Reviewed-by: Kees Cook <keescook@chromium.org> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: linux-api@vger.kernel.org Reviewed-by: Mickaël Salaün <mic@digikod.net> [PM: forward ported beyond v6.6 due merge window changes] Signed-off-by: Paul Moore <paul@paul-moore.com>
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2fd0ebad |
| 14-Sep-2023 |
Sohil Mehta <sohil.mehta@intel.com> |
arch: Reserve map_shadow_stack() syscall number for all architectures
commit c35559f94ebc ("x86/shstk: Introduce map_shadow_stack syscall") recently added support for map_shadow_stack() but it is li
arch: Reserve map_shadow_stack() syscall number for all architectures
commit c35559f94ebc ("x86/shstk: Introduce map_shadow_stack syscall") recently added support for map_shadow_stack() but it is limited to x86 only for now. There is a possibility that other architectures (namely, arm64 and RISC-V), that are implementing equivalent support for shadow stacks, might need to add support for it.
Independent of that, reserving arch-specific syscall numbers in the syscall tables of all architectures is good practice and would help avoid future conflicts. map_shadow_stack() is marked as a conditional syscall in sys_ni.c. Adding it to the syscall tables of other architectures is harmless and would return ENOSYS when exercised.
Note, map_shadow_stack() was assigned #453 during the merge process since #452 was taken by fchmodat2().
For Powerpc, map it to sys_ni_syscall() as is the norm for Powerpc syscall tables.
For Alpha, map_shadow_stack() takes up #563 as Alpha still diverges from the common syscall numbering system in the other architectures.
Link: https://lore.kernel.org/lkml/20230515212255.GA562920@debug.ba.rivosinc.com/ Link: https://lore.kernel.org/lkml/b402b80b-a7c6-4ef0-b977-c0f5f582b78a@sirena.org.uk/
Signed-off-by: Sohil Mehta <sohil.mehta@intel.com> Reviewed-by: Rick Edgecombe <rick.p.edgecombe@intel.com> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Acked-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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ccab211a |
| 10-Jul-2023 |
Sohil Mehta <sohil.mehta@intel.com> |
syscalls: Cleanup references to sys_lookup_dcookie()
commit 'be65de6b03aa ("fs: Remove dcookies support")' removed the syscall definition for lookup_dcookie. However, syscall tables still point to
syscalls: Cleanup references to sys_lookup_dcookie()
commit 'be65de6b03aa ("fs: Remove dcookies support")' removed the syscall definition for lookup_dcookie. However, syscall tables still point to the old sys_lookup_dcookie() definition. Update syscall tables of all architectures to directly point to sys_ni_syscall() instead.
Signed-off-by: Sohil Mehta <sohil.mehta@intel.com> Reviewed-by: Randy Dunlap <rdunlap@infradead.org> Acked-by: Namhyung Kim <namhyung@kernel.org> # for perf Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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0f4b5f97 |
| 21-Sep-2023 |
peterz@infradead.org <peterz@infradead.org> |
futex: Add sys_futex_requeue()
Finish off the 'simple' futex2 syscall group by adding sys_futex_requeue(). Unlike sys_futex_{wait,wake}() its arguments are too numerous to fit into a regular syscall
futex: Add sys_futex_requeue()
Finish off the 'simple' futex2 syscall group by adding sys_futex_requeue(). Unlike sys_futex_{wait,wake}() its arguments are too numerous to fit into a regular syscall. As such, use struct futex_waitv to pass the 'source' and 'destination' futexes to the syscall.
This syscall implements what was previously known as FUTEX_CMP_REQUEUE and uses {val, uaddr, flags} for source and {uaddr, flags} for destination.
This design explicitly allows requeueing between different types of futex by having a different flags word per uaddr.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Link: https://lore.kernel.org/r/20230921105248.511860556@noisy.programming.kicks-ass.net
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#
cb8c4312 |
| 21-Sep-2023 |
peterz@infradead.org <peterz@infradead.org> |
futex: Add sys_futex_wait()
To complement sys_futex_waitv()/wake(), add sys_futex_wait(). This syscall implements what was previously known as FUTEX_WAIT_BITSET except it uses 'unsigned long' for th
futex: Add sys_futex_wait()
To complement sys_futex_waitv()/wake(), add sys_futex_wait(). This syscall implements what was previously known as FUTEX_WAIT_BITSET except it uses 'unsigned long' for the value and bitmask arguments, takes timespec and clockid_t arguments for the absolute timeout and uses FUTEX2 flags.
The 'unsigned long' allows FUTEX2_SIZE_U64 on 64bit platforms.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Link: https://lore.kernel.org/r/20230921105248.164324363@noisy.programming.kicks-ass.net
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#
9f6c532f |
| 21-Sep-2023 |
peterz@infradead.org <peterz@infradead.org> |
futex: Add sys_futex_wake()
To complement sys_futex_waitv() add sys_futex_wake(). This syscall implements what was previously known as FUTEX_WAKE_BITSET except it uses 'unsigned long' for the bitmas
futex: Add sys_futex_wake()
To complement sys_futex_waitv() add sys_futex_wake(). This syscall implements what was previously known as FUTEX_WAKE_BITSET except it uses 'unsigned long' for the bitmask and takes FUTEX2 flags.
The 'unsigned long' allows FUTEX2_SIZE_U64 on 64bit platforms.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Link: https://lore.kernel.org/r/20230921105247.936205525@noisy.programming.kicks-ass.net
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#
78252deb |
| 11-Jul-2023 |
Palmer Dabbelt <palmer@sifive.com> |
arch: Register fchmodat2, usually as syscall 452
This registers the new fchmodat2 syscall in most places as nuber 452, with alpha being the exception where it's 562. I found all these sites by grep
arch: Register fchmodat2, usually as syscall 452
This registers the new fchmodat2 syscall in most places as nuber 452, with alpha being the exception where it's 562. I found all these sites by grepping for fspick, which I assume has found me everything.
Signed-off-by: Palmer Dabbelt <palmer@sifive.com> Signed-off-by: Alexey Gladkov <legion@kernel.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Message-Id: <a677d521f048e4ca439e7080a5328f21eb8e960e.1689092120.git.legion@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
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#
946e697c |
| 10-May-2023 |
Nhat Pham <nphamcs@gmail.com> |
cachestat: wire up cachestat for other architectures
cachestat is previously only wired in for x86 (and architectures using the generic unistd.h table):
https://lore.kernel.org/lkml/20230503013608.
cachestat: wire up cachestat for other architectures
cachestat is previously only wired in for x86 (and architectures using the generic unistd.h table):
https://lore.kernel.org/lkml/20230503013608.2431726-1-nphamcs@gmail.com/
This patch wires cachestat in for all the other architectures.
[nphamcs@gmail.com: wire up cachestat for arm64] Link: https://lkml.kernel.org/r/20230511092843.3896327-1-nphamcs@gmail.com Link: https://lkml.kernel.org/r/20230510195806.2902878-1-nphamcs@gmail.com Signed-off-by: Nhat Pham <nphamcs@gmail.com> Tested-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc] Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> [m68k] Reviewed-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Heiko Carstens <hca@linux.ibm.com> [s390] Cc: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@linux.ibm.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Cc: Chris Zankel <chris@zankel.net> Cc: David S. Miller <davem@davemloft.net> Cc: Helge Deller <deller@gmx.de> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> Cc: Matt Turner <mattst88@gmail.com> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: Michal Simek <monstr@monstr.eu> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Richard Henderson <richard.henderson@linaro.org> Cc: Rich Felker <dalias@libc.org> Cc: Russell King <linux@armlinux.org.uk> Cc: Sven Schnelle <svens@linux.ibm.com> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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#
21b084fd |
| 14-Jan-2022 |
Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> |
mm/mempolicy: wire up syscall set_mempolicy_home_node
Link: https://lkml.kernel.org/r/20211202123810.267175-4-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
mm/mempolicy: wire up syscall set_mempolicy_home_node
Link: https://lkml.kernel.org/r/20211202123810.267175-4-aneesh.kumar@linux.ibm.com Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com> Cc: Ben Widawsky <ben.widawsky@intel.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Feng Tang <feng.tang@intel.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Andi Kleen <ak@linux.intel.com> Cc: Dan Williams <dan.j.williams@intel.com> Cc: Huang Ying <ying.huang@intel.com> Cc: <linux-api@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
a0eb2da9 |
| 24-Nov-2021 |
André Almeida <andrealmeid@collabora.com> |
futex: Wireup futex_waitv syscall
Wireup futex_waitv syscall for all remaining archs.
Signed-off-by: André Almeida <andrealmeid@collabora.com> Acked-by: Max Filippov <jcmvbkbc@gmail.com> Acked-by:
futex: Wireup futex_waitv syscall
Wireup futex_waitv syscall for all remaining archs.
Signed-off-by: André Almeida <andrealmeid@collabora.com> Acked-by: Max Filippov <jcmvbkbc@gmail.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Tested-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc) Signed-off-by: Arnd Bergmann <arnd@arndb.de>
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#
59ab844e |
| 08-Sep-2021 |
Arnd Bergmann <arnd@arndb.de> |
compat: remove some compat entry points
These are all handled correctly when calling the native system call entry point, so remove the special cases.
Link: https://lkml.kernel.org/r/20210727144859.
compat: remove some compat entry points
These are all handled correctly when calling the native system call entry point, so remove the special cases.
Link: https://lkml.kernel.org/r/20210727144859.4150043-6-arnd@kernel.org Signed-off-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Feng Tang <feng.tang@intel.com> Cc: Heiko Carstens <hca@linux.ibm.com> Cc: Helge Deller <deller@gmx.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.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>
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#
dce49103 |
| 02-Sep-2021 |
Suren Baghdasaryan <surenb@google.com> |
mm: wire up syscall process_mrelease
Split off from prev patch in the series that implements the syscall.
Link: https://lkml.kernel.org/r/20210809185259.405936-2-surenb@google.com Signed-off-by: Su
mm: wire up syscall process_mrelease
Split off from prev patch in the series that implements the syscall.
Link: https://lkml.kernel.org/r/20210809185259.405936-2-surenb@google.com Signed-off-by: Suren Baghdasaryan <surenb@google.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Christian Brauner <christian.brauner@ubuntu.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: David Hildenbrand <david@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Florian Weimer <fweimer@redhat.com> Cc: Jan Engelhardt <jengelh@inai.de> Cc: Jann Horn <jannh@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Michal Hocko <mhocko@suse.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Rik van Riel <riel@surriel.com> Cc: Roman Gushchin <guro@fb.com> Cc: Shakeel Butt <shakeelb@google.com> Cc: Tim Murray <timmurray@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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#
b48c7236 |
| 29-Jun-2021 |
Eric W. Biederman <ebiederm@xmission.com> |
exit/bdflush: Remove the deprecated bdflush system call
The bdflush system call has been deprecated for a very long time. Recently Michael Schmitz tested[1] and found that the last known caller of o
exit/bdflush: Remove the deprecated bdflush system call
The bdflush system call has been deprecated for a very long time. Recently Michael Schmitz tested[1] and found that the last known caller of of the bdflush system call is unaffected by it's removal.
Since the code is not needed delete it.
[1] https://lkml.kernel.org/r/36123b5d-daa0-6c2b-f2d4-a942f069fd54@gmail.com Link: https://lkml.kernel.org/r/87sg10quue.fsf_-_@disp2133 Tested-by: Michael Schmitz <schmitzmic@gmail.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Cyril Hrubis <chrubis@suse.cz> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
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#
65ffb3d6 |
| 31-May-2021 |
Jan Kara <jack@suse.cz> |
quota: Wire up quotactl_fd syscall
Wire up the quotactl_fd syscall.
Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz>
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5b9fedb3 |
| 17-May-2021 |
Jan Kara <jack@suse.cz> |
quota: Disable quotactl_path syscall
In commit fa8b90070a80 ("quota: wire up quotactl_path") we have wired up new quotactl_path syscall. However some people in LWN discussion have objected that the
quota: Disable quotactl_path syscall
In commit fa8b90070a80 ("quota: wire up quotactl_path") we have wired up new quotactl_path syscall. However some people in LWN discussion have objected that the path based syscall is missing dirfd and flags argument which is mostly standard for contemporary path based syscalls. Indeed they have a point and after a discussion with Christian Brauner and Sascha Hauer I've decided to disable the syscall for now and update its API. Since there is no userspace currently using that syscall and it hasn't been released in any major release, we should be fine.
CC: Christian Brauner <christian.brauner@ubuntu.com> CC: Sascha Hauer <s.hauer@pengutronix.de> Link: https://lore.kernel.org/lkml/20210512153621.n5u43jsytbik4yze@wittgenstein Signed-off-by: Jan Kara <jack@suse.cz>
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#
a49f4f81 |
| 22-Apr-2021 |
Mickaël Salaün <mic@linux.microsoft.com> |
arch: Wire up Landlock syscalls
Wire up the following system calls for all architectures: * landlock_create_ruleset(2) * landlock_add_rule(2) * landlock_restrict_self(2)
Cc: Arnd Bergmann <arnd@arn
arch: Wire up Landlock syscalls
Wire up the following system calls for all architectures: * landlock_create_ruleset(2) * landlock_add_rule(2) * landlock_restrict_self(2)
Cc: Arnd Bergmann <arnd@arndb.de> Cc: James Morris <jmorris@namei.org> Cc: Jann Horn <jannh@google.com> Cc: Kees Cook <keescook@chromium.org> Cc: Serge E. Hallyn <serge@hallyn.com> Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com> Link: https://lore.kernel.org/r/20210422154123.13086-10-mic@digikod.net Signed-off-by: James Morris <jamorris@linux.microsoft.com>
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#
fa8b9007 |
| 04-Mar-2021 |
Sascha Hauer <s.hauer@pengutronix.de> |
quota: wire up quotactl_path
Wire up the quotactl_path syscall added in the previous patch.
Link: https://lore.kernel.org/r/20210304123541.30749-3-s.hauer@pengutronix.de Signed-off-by: Sascha Hauer
quota: wire up quotactl_path
Wire up the quotactl_path syscall added in the previous patch.
Link: https://lore.kernel.org/r/20210304123541.30749-3-s.hauer@pengutronix.de Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz>
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#
2a186721 |
| 21-Jan-2021 |
Christian Brauner <christian.brauner@ubuntu.com> |
fs: add mount_setattr()
This implements the missing mount_setattr() syscall. While the new mount api allows to change the properties of a superblock there is currently no way to change the propertie
fs: add mount_setattr()
This implements the missing mount_setattr() syscall. While the new mount api allows to change the properties of a superblock there is currently no way to change the properties of a mount or a mount tree using file descriptors which the new mount api is based on. In addition the old mount api has the restriction that mount options cannot be applied recursively. This hasn't changed since changing mount options on a per-mount basis was implemented in [1] and has been a frequent request not just for convenience but also for security reasons. The legacy mount syscall is unable to accommodate this behavior without introducing a whole new set of flags because MS_REC | MS_REMOUNT | MS_BIND | MS_RDONLY | MS_NOEXEC | [...] only apply the mount option to the topmost mount. Changing MS_REC to apply to the whole mount tree would mean introducing a significant uapi change and would likely cause significant regressions.
The new mount_setattr() syscall allows to recursively clear and set mount options in one shot. Multiple calls to change mount options requesting the same changes are idempotent:
int mount_setattr(int dfd, const char *path, unsigned flags, struct mount_attr *uattr, size_t usize);
Flags to modify path resolution behavior are specified in the @flags argument. Currently, AT_EMPTY_PATH, AT_RECURSIVE, AT_SYMLINK_NOFOLLOW, and AT_NO_AUTOMOUNT are supported. If useful, additional lookup flags to restrict path resolution as introduced with openat2() might be supported in the future.
The mount_setattr() syscall can be expected to grow over time and is designed with extensibility in mind. It follows the extensible syscall pattern we have used with other syscalls such as openat2(), clone3(), sched_{set,get}attr(), and others. The set of mount options is passed in the uapi struct mount_attr which currently has the following layout:
struct mount_attr { __u64 attr_set; __u64 attr_clr; __u64 propagation; __u64 userns_fd; };
The @attr_set and @attr_clr members are used to clear and set mount options. This way a user can e.g. request that a set of flags is to be raised such as turning mounts readonly by raising MOUNT_ATTR_RDONLY in @attr_set while at the same time requesting that another set of flags is to be lowered such as removing noexec from a mount tree by specifying MOUNT_ATTR_NOEXEC in @attr_clr.
Note, since the MOUNT_ATTR_<atime> values are an enum starting from 0, not a bitmap, users wanting to transition to a different atime setting cannot simply specify the atime setting in @attr_set, but must also specify MOUNT_ATTR__ATIME in the @attr_clr field. So we ensure that MOUNT_ATTR__ATIME can't be partially set in @attr_clr and that @attr_set can't have any atime bits set if MOUNT_ATTR__ATIME isn't set in @attr_clr.
The @propagation field lets callers specify the propagation type of a mount tree. Propagation is a single property that has four different settings and as such is not really a flag argument but an enum. Specifically, it would be unclear what setting and clearing propagation settings in combination would amount to. The legacy mount() syscall thus forbids the combination of multiple propagation settings too. The goal is to keep the semantics of mount propagation somewhat simple as they are overly complex as it is.
The @userns_fd field lets user specify a user namespace whose idmapping becomes the idmapping of the mount. This is implemented and explained in detail in the next patch.
[1]: commit 2e4b7fcd9260 ("[PATCH] r/o bind mounts: honor mount writer counts at remount")
Link: https://lore.kernel.org/r/20210121131959.646623-35-christian.brauner@ubuntu.com Cc: David Howells <dhowells@redhat.com> Cc: Aleksa Sarai <cyphar@cyphar.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org Cc: linux-api@vger.kernel.org Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
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#
450f68e2 |
| 20-Dec-2020 |
Heiko Carstens <hca@linux.ibm.com> |
epoll: fix compat syscall wire up of epoll_pwait2
Commit b0a0c2615f6f ("epoll: wire up syscall epoll_pwait2") wired up the 64 bit syscall instead of the compat variant in a couple of places.
Fixes:
epoll: fix compat syscall wire up of epoll_pwait2
Commit b0a0c2615f6f ("epoll: wire up syscall epoll_pwait2") wired up the 64 bit syscall instead of the compat variant in a couple of places.
Fixes: b0a0c2615f6f ("epoll: wire up syscall epoll_pwait2") Signed-off-by: Heiko Carstens <hca@linux.ibm.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Willem de Bruijn <willemb@google.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Will Deacon <will@kernel.org> Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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b0a0c261 |
| 18-Dec-2020 |
Willem de Bruijn <willemb@google.com> |
epoll: wire up syscall epoll_pwait2
Split off from prev patch in the series that implements the syscall.
Link: https://lkml.kernel.org/r/20201121144401.3727659-4-willemdebruijn.kernel@gmail.com Sig
epoll: wire up syscall epoll_pwait2
Split off from prev patch in the series that implements the syscall.
Link: https://lkml.kernel.org/r/20201121144401.3727659-4-willemdebruijn.kernel@gmail.com Signed-off-by: Willem de Bruijn <willemb@google.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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ecb8ac8b |
| 17-Oct-2020 |
Minchan Kim <minchan@kernel.org> |
mm/madvise: introduce process_madvise() syscall: an external memory hinting API
There is usecase that System Management Software(SMS) want to give a memory hint like MADV_[COLD|PAGEEOUT] to other pr
mm/madvise: introduce process_madvise() syscall: an external memory hinting API
There is usecase that System Management Software(SMS) want to give a memory hint like MADV_[COLD|PAGEEOUT] to other processes and in the case of Android, it is the ActivityManagerService.
The information required to make the reclaim decision is not known to the app. Instead, it is known to the centralized userspace daemon(ActivityManagerService), and that daemon must be able to initiate reclaim on its own without any app involvement.
To solve the issue, this patch introduces a new syscall process_madvise(2). It uses pidfd of an external process to give the hint. It also supports vector address range because Android app has thousands of vmas due to zygote so it's totally waste of CPU and power if we should call the syscall one by one for each vma.(With testing 2000-vma syscall vs 1-vector syscall, it showed 15% performance improvement. I think it would be bigger in real practice because the testing ran very cache friendly environment).
Another potential use case for the vector range is to amortize the cost ofTLB shootdowns for multiple ranges when using MADV_DONTNEED; this could benefit users like TCP receive zerocopy and malloc implementations. In future, we could find more usecases for other advises so let's make it happens as API since we introduce a new syscall at this moment. With that, existing madvise(2) user could replace it with process_madvise(2) with their own pid if they want to have batch address ranges support feature.
ince it could affect other process's address range, only privileged process(PTRACE_MODE_ATTACH_FSCREDS) or something else(e.g., being the same UID) gives it the right to ptrace the process could use it successfully. The flag argument is reserved for future use if we need to extend the API.
I think supporting all hints madvise has/will supported/support to process_madvise is rather risky. Because we are not sure all hints make sense from external process and implementation for the hint may rely on the caller being in the current context so it could be error-prone. Thus, I just limited hints as MADV_[COLD|PAGEOUT] in this patch.
If someone want to add other hints, we could hear the usecase and review it for each hint. It's safer for maintenance rather than introducing a buggy syscall but hard to fix it later.
So finally, the API is as follows,
ssize_t process_madvise(int pidfd, const struct iovec *iovec, unsigned long vlen, int advice, unsigned int flags);
DESCRIPTION The process_madvise() system call is used to give advice or directions to the kernel about the address ranges from external process as well as local process. It provides the advice to address ranges of process described by iovec and vlen. The goal of such advice is to improve system or application performance.
The pidfd selects the process referred to by the PID file descriptor specified in pidfd. (See pidofd_open(2) for further information)
The pointer iovec points to an array of iovec structures, defined in <sys/uio.h> as:
struct iovec { void *iov_base; /* starting address */ size_t iov_len; /* number of bytes to be advised */ };
The iovec describes address ranges beginning at address(iov_base) and with size length of bytes(iov_len).
The vlen represents the number of elements in iovec.
The advice is indicated in the advice argument, which is one of the following at this moment if the target process specified by pidfd is external.
MADV_COLD MADV_PAGEOUT
Permission to provide a hint to external process is governed by a ptrace access mode PTRACE_MODE_ATTACH_FSCREDS check; see ptrace(2).
The process_madvise supports every advice madvise(2) has if target process is in same thread group with calling process so user could use process_madvise(2) to extend existing madvise(2) to support vector address ranges.
RETURN VALUE On success, process_madvise() returns the number of bytes advised. This return value may be less than the total number of requested bytes, if an error occurred. The caller should check return value to determine whether a partial advice occurred.
FAQ:
Q.1 - Why does any external entity have better knowledge?
Quote from Sandeep
"For Android, every application (including the special SystemServer) are forked from Zygote. The reason of course is to share as many libraries and classes between the two as possible to benefit from the preloading during boot.
After applications start, (almost) all of the APIs end up calling into this SystemServer process over IPC (binder) and back to the application.
In a fully running system, the SystemServer monitors every single process periodically to calculate their PSS / RSS and also decides which process is "important" to the user for interactivity.
So, because of how these processes start _and_ the fact that the SystemServer is looping to monitor each process, it does tend to *know* which address range of the application is not used / useful.
Besides, we can never rely on applications to clean things up themselves. We've had the "hey app1, the system is low on memory, please trim your memory usage down" notifications for a long time[1]. They rely on applications honoring the broadcasts and very few do.
So, if we want to avoid the inevitable killing of the application and restarting it, some way to be able to tell the OS about unimportant memory in these applications will be useful.
- ssp
Q.2 - How to guarantee the race(i.e., object validation) between when giving a hint from an external process and get the hint from the target process?
process_madvise operates on the target process's address space as it exists at the instant that process_madvise is called. If the space target process can run between the time the process_madvise process inspects the target process address space and the time that process_madvise is actually called, process_madvise may operate on memory regions that the calling process does not expect. It's the responsibility of the process calling process_madvise to close this race condition. For example, the calling process can suspend the target process with ptrace, SIGSTOP, or the freezer cgroup so that it doesn't have an opportunity to change its own address space before process_madvise is called. Another option is to operate on memory regions that the caller knows a priori will be unchanged in the target process. Yet another option is to accept the race for certain process_madvise calls after reasoning that mistargeting will do no harm. The suggested API itself does not provide synchronization. It also apply other APIs like move_pages, process_vm_write.
The race isn't really a problem though. Why is it so wrong to require that callers do their own synchronization in some manner? Nobody objects to write(2) merely because it's possible for two processes to open the same file and clobber each other's writes --- instead, we tell people to use flock or something. Think about mmap. It never guarantees newly allocated address space is still valid when the user tries to access it because other threads could unmap the memory right before. That's where we need synchronization by using other API or design from userside. It shouldn't be part of API itself. If someone needs more fine-grained synchronization rather than process level, there were two ideas suggested - cookie[2] and anon-fd[3]. Both are applicable via using last reserved argument of the API but I don't think it's necessary right now since we have already ways to prevent the race so don't want to add additional complexity with more fine-grained optimization model.
To make the API extend, it reserved an unsigned long as last argument so we could support it in future if someone really needs it.
Q.3 - Why doesn't ptrace work?
Injecting an madvise in the target process using ptrace would not work for us because such injected madvise would have to be executed by the target process, which means that process would have to be runnable and that creates the risk of the abovementioned race and hinting a wrong VMA. Furthermore, we want to act the hint in caller's context, not the callee's, because the callee is usually limited in cpuset/cgroups or even freezed state so they can't act by themselves quick enough, which causes more thrashing/kill. It doesn't work if the target process are ptraced(e.g., strace, debugger, minidump) because a process can have at most one ptracer.
[1] https://developer.android.com/topic/performance/memory"
[2] process_getinfo for getting the cookie which is updated whenever vma of process address layout are changed - Daniel Colascione - https://lore.kernel.org/lkml/20190520035254.57579-1-minchan@kernel.org/T/#m7694416fd179b2066a2c62b5b139b14e3894e224
[3] anonymous fd which is used for the object(i.e., address range) validation - Michal Hocko - https://lore.kernel.org/lkml/20200120112722.GY18451@dhcp22.suse.cz/
[minchan@kernel.org: fix process_madvise build break for arm64] Link: http://lkml.kernel.org/r/20200303145756.GA219683@google.com [minchan@kernel.org: fix build error for mips of process_madvise] Link: http://lkml.kernel.org/r/20200508052517.GA197378@google.com [akpm@linux-foundation.org: fix patch ordering issue] [akpm@linux-foundation.org: fix arm64 whoops] [minchan@kernel.org: make process_madvise() vlen arg have type size_t, per Florian] [akpm@linux-foundation.org: fix i386 build] [sfr@canb.auug.org.au: fix syscall numbering] Link: https://lkml.kernel.org/r/20200905142639.49fc3f1a@canb.auug.org.au [sfr@canb.auug.org.au: madvise.c needs compat.h] Link: https://lkml.kernel.org/r/20200908204547.285646b4@canb.auug.org.au [minchan@kernel.org: fix mips build] Link: https://lkml.kernel.org/r/20200909173655.GC2435453@google.com [yuehaibing@huawei.com: remove duplicate header which is included twice] Link: https://lkml.kernel.org/r/20200915121550.30584-1-yuehaibing@huawei.com [minchan@kernel.org: do not use helper functions for process_madvise] Link: https://lkml.kernel.org/r/20200921175539.GB387368@google.com [akpm@linux-foundation.org: pidfd_get_pid() gained an argument] [sfr@canb.auug.org.au: fix up for "iov_iter: transparently handle compat iovecs in import_iovec"] Link: https://lkml.kernel.org/r/20200928212542.468e1fef@canb.auug.org.au
Signed-off-by: Minchan Kim <minchan@kernel.org> Signed-off-by: YueHaibing <yuehaibing@huawei.com> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Suren Baghdasaryan <surenb@google.com> Reviewed-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: David Rientjes <rientjes@google.com> Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com> Cc: Brian Geffon <bgeffon@google.com> Cc: Christian Brauner <christian@brauner.io> Cc: Daniel Colascione <dancol@google.com> Cc: Jann Horn <jannh@google.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: John Dias <joaodias@google.com> Cc: Kirill Tkhai <ktkhai@virtuozzo.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Oleksandr Natalenko <oleksandr@redhat.com> Cc: Sandeep Patil <sspatil@google.com> Cc: SeongJae Park <sj38.park@gmail.com> Cc: SeongJae Park <sjpark@amazon.de> Cc: Shakeel Butt <shakeelb@google.com> Cc: Sonny Rao <sonnyrao@google.com> Cc: Tim Murray <timmurray@google.com> Cc: Christian Brauner <christian.brauner@ubuntu.com> Cc: Florian Weimer <fw@deneb.enyo.de> Cc: <linux-man@vger.kernel.org> Link: http://lkml.kernel.org/r/20200302193630.68771-3-minchan@kernel.org Link: http://lkml.kernel.org/r/20200508183320.GA125527@google.com Link: http://lkml.kernel.org/r/20200622192900.22757-4-minchan@kernel.org Link: https://lkml.kernel.org/r/20200901000633.1920247-4-minchan@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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c3973b40 |
| 25-Sep-2020 |
Christoph Hellwig <hch@lst.de> |
mm: remove compat_process_vm_{readv,writev}
Now that import_iovec handles compat iovecs, the native syscalls can be used for the compat case as well.
Signed-off-by: Christoph Hellwig <hch@lst.de> S
mm: remove compat_process_vm_{readv,writev}
Now that import_iovec handles compat iovecs, the native syscalls can be used for the compat case as well.
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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598b3cec |
| 25-Sep-2020 |
Christoph Hellwig <hch@lst.de> |
fs: remove compat_sys_vmsplice
Now that import_iovec handles compat iovecs, the native vmsplice syscall can be used for the compat case as well.
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed
fs: remove compat_sys_vmsplice
Now that import_iovec handles compat iovecs, the native vmsplice syscall can be used for the compat case as well.
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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5f764d62 |
| 25-Sep-2020 |
Christoph Hellwig <hch@lst.de> |
fs: remove the compat readv/writev syscalls
Now that import_iovec handles compat iovecs, the native readv and writev syscalls can be used for the compat case as well.
Signed-off-by: Christoph Hellw
fs: remove the compat readv/writev syscalls
Now that import_iovec handles compat iovecs, the native readv and writev syscalls can be used for the compat case as well.
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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