linux.git/arch/x86/kernel/cpu/resctrl/pseudo_lock.c, branch v5.17

x86/resctrl: Add a helper to read/set the CDP configuration

2021-08-11T13:54:26+00:00

Whether CDP is enabled for a hardware resource like the L3 cache can be
found by inspecting the alloc_enabled flags of the L3CODE/L3DATA struct
rdt_hw_resources, even if they aren't in use.

Once these resources are merged, the flags can't be compared. Whether
CDP is enabled needs tracking explicitly. If another architecture is
emulating CDP the behaviour may not be per-resource. 'cdp_capable' needs
to be visible to resctrl, even if its not in use, as this affects the
padding of the schemata table visible to user-space.

Add cdp_enabled to struct rdt_hw_resource and cdp_capable to struct
rdt_resource. Add resctrl_arch_set_cdp_enabled() to let resctrl enable
or disable CDP on a resource. resctrl_arch_get_cdp_enabled() lets it
read the current state.

Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov 
Reviewed-by: Jamie Iles 
Reviewed-by: Reinette Chatre 
Tested-by: Babu Moger 
Link: https://lkml.kernel.org/r/20210728170637.25610-12-james.morse@arm.com

x86/resctrl: Swizzle rdt_resource and resctrl_schema in pseudo_lock_region

2021-08-11T13:51:45+00:00

struct pseudo_lock_region points to the rdt_resource.

Once the resources are merged, this won't be unique. The resource name
is moving into the schema, so that the filesystem portions of resctrl can
generate it.

Swap pseudo_lock_region's rdt_resource pointer for a schema pointer.

Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov 
Reviewed-by: Jamie Iles 
Reviewed-by: Reinette Chatre 
Tested-by: Babu Moger 
Link: https://lkml.kernel.org/r/20210728170637.25610-11-james.morse@arm.com

x86/resctrl: Split struct rdt_resource

2021-08-11T09:51:34+00:00

resctrl is the defacto Linux ABI for SoC resource partitioning features.

To support it on another architecture, it needs to be abstracted from
the features provided by Intel RDT and AMD PQoS, and moved to /fs/.
struct rdt_resource contains a mix of architecture private details
and properties of the filesystem interface user-space uses.

Start by splitting struct rdt_resource, into an architecture private
'hw' struct, which contains the common resctrl structure that would be
used by any architecture. The foreach helpers are most commonly used by
the filesystem code, and should return the common resctrl structure.
for_each_rdt_resource() is changed to walk the common structure in its
parent arch private structure.

Move as much of the structure as possible into the common structure
in the core code's header file. The x86 hardware accessors remain
part of the architecture private code, as do num_closid, mon_scale
and mbm_width.

mon_scale and mbm_width are used to detect overflow of the hardware
counters, and convert them from their native size to bytes. Any
cross-architecture abstraction should be in terms of bytes, making
these properties private.

The hardware's num_closid is kept in the private structure to force the
filesystem code to use a helper to access it. MPAM would return a single
value for the system, regardless of the resource. Using the helper
prevents this field from being confused with the version of num_closid
that is being exposed to user-space (added in a later patch).

After this split, filesystem code touching a 'hw' struct indicates
where an abstraction is needed.

Splitting this structure only moves types around, and should not lead
to any change in behaviour.

Signed-off-by: James Morse 
Signed-off-by: Borislav Petkov 
Reviewed-by: Jamie Iles 
Reviewed-by: Reinette Chatre 
Tested-by: Babu Moger 
Link: https://lkml.kernel.org/r/20210728170637.25610-2-james.morse@arm.com

x86/resctrl: Fix kernel-doc in pseudo_lock.c

2021-06-24T08:21:05+00:00

Add undocumented parameters detected by scripts/kernel-doc.

Signed-off-by: Fabio M. De Francesco 
Signed-off-by: Borislav Petkov 
Reviewed-by: Reinette Chatre 
Link: https://lkml.kernel.org/r/20210616181530.4094-1-fmdefrancesco@gmail.com

Revert "mremap: don't allow MREMAP_DONTUNMAP on special_mappings and aio"

2021-04-30T18:20:39+00:00

This reverts commit cd544fd1dc9293c6702fab6effa63dac1cc67e99.

As discussed in [1] this commit was a no-op because the mapping type was
checked in vma_to_resize before move_vma is ever called.  This meant that
vm_ops->mremap() would never be called on such mappings.  Furthermore,
we've since expanded support of MREMAP_DONTUNMAP to non-anonymous
mappings, and these special mappings are still protected by the existing
check of !VM_DONTEXPAND and !VM_PFNMAP which will result in a -EINVAL.

1. https://lkml.org/lkml/2020/12/28/2340

Link: https://lkml.kernel.org/r/20210323182520.2712101-2-bgeffon@google.com
Signed-off-by: Brian Geffon 
Acked-by: Hugh Dickins 
Reviewed-by: Dmitry Safonov <0x7f454c46@gmail.com>
Cc: Alejandro Colomar 
Cc: Andrea Arcangeli 
Cc: Andy Lutomirski 
Cc: Axel Rasmussen 
Cc: "Kirill A . Shutemov" 
Cc: Lokesh Gidra 
Cc: Michael Kerrisk 
Cc: "Michael S . Tsirkin" 
Cc: Mike Rapoport 
Cc: Minchan Kim 
Cc: Peter Xu 
Cc: Sonny Rao 
Cc: Vlastimil Babka 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

x86: Fix various typos in comments

2021-03-18T14:31:53+00:00

Fix ~144 single-word typos in arch/x86/ code comments.

Doing this in a single commit should reduce the churn.

Signed-off-by: Ingo Molnar 
Cc: Borislav Petkov 
Cc: Thomas Gleixner 
Cc: Peter Zijlstra 
Cc: Paolo Bonzini 
Cc: Bjorn Helgaas 
Cc: linux-kernel@vger.kernel.org

mremap: don't allow MREMAP_DONTUNMAP on special_mappings and aio

2020-12-15T20:13:41+00:00

As kernel expect to see only one of such mappings, any further operations
on the VMA-copy may be unexpected by the kernel.  Maybe it's being on the
safe side, but there doesn't seem to be any expected use-case for this, so
restrict it now.

Link: https://lkml.kernel.org/r/20201013013416.390574-4-dima@arista.com
Fixes: commit e346b3813067 ("mm/mremap: add MREMAP_DONTUNMAP to mremap()")
Signed-off-by: Dmitry Safonov 
Cc: Alexander Viro 
Cc: Andy Lutomirski 
Cc: Brian Geffon 
Cc: Catalin Marinas 
Cc: Dan Carpenter 
Cc: Dan Williams 
Cc: Dave Jiang 
Cc: Hugh Dickins 
Cc: Ingo Molnar 
Cc: Jason Gunthorpe 
Cc: John Hubbard 
Cc: "Kirill A. Shutemov" 
Cc: Mike Kravetz 
Cc: Minchan Kim 
Cc: Ralph Campbell 
Cc: Russell King 
Cc: Thomas Bogendoerfer 
Cc: Thomas Gleixner 
Cc: Vishal Verma 
Cc: Vlastimil Babka 
Cc: Will Deacon 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mmap locking API: convert mmap_sem comments

2020-06-09T16:39:14+00:00

Convert comments that reference mmap_sem to reference mmap_lock instead.

[akpm@linux-foundation.org: fix up linux-next leftovers]
[akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil]
[akpm@linux-foundation.org: more linux-next fixups, per Michel]

Signed-off-by: Michel Lespinasse 
Signed-off-by: Andrew Morton 
Reviewed-by: Vlastimil Babka 
Reviewed-by: Daniel Jordan 
Cc: Davidlohr Bueso 
Cc: David Rientjes 
Cc: Hugh Dickins 
Cc: Jason Gunthorpe 
Cc: Jerome Glisse 
Cc: John Hubbard 
Cc: Laurent Dufour 
Cc: Liam Howlett 
Cc: Matthew Wilcox 
Cc: Peter Zijlstra 
Cc: Ying Han 
Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com
Signed-off-by: Linus Torvalds

x86/resctrl: Rename asm/resctrl_sched.h to asm/resctrl.h

2020-05-06T15:45:22+00:00

asm/resctrl_sched.h is dedicated to the code used for configuration
of the CPU resource control state when a task is scheduled.

Rename resctrl_sched.h to resctrl.h in preparation of additions that
will no longer make this file dedicated to work done during scheduling.

No functional change.

Suggested-by: Borislav Petkov 
Signed-off-by: Reinette Chatre 
Signed-off-by: Borislav Petkov 
Link: https://lkml.kernel.org/r/6914e0ef880b539a82a6d889f9423496d471ad1d.1588715690.git.reinette.chatre@intel.com

Merge branch 'x86-cache-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2019-07-09T00:25:53+00:00

Pull x86 cache resource control update from Ingo Molnar:
 "Two cleanup patches"

* 'x86-cache-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/resctrl: Cleanup cbm_ensure_valid()
  x86/resctrl: Use _ASM_BX to avoid ifdeffery