The current fence_y_offset calculation is broken. I think it more or
less used to do the right thing, but then I changed the plane code
to put the final x/y source offsets back into the src rectangle so
now it's just subtraacting the same value from itself. The code would
never have worked if we allowed the framebuffer to have a non-zero
offset.
Let's do this in a better way by just calculating the fence_y_offset
from the final plane surface offset. Note that we don't align the
plane surface address to fence rows so with horizontal panning there's
often a horizontal offset from the fence start to the surface address
as well. We have no way to tell the hardware about that so we just
ignore it. Based on some quick tests the invlidation still happens
correctly. I presume due to the invalidation nuking at least the full
line (or a segment of multiple lines).
Fixes: 54d4d719fa ("drm/i915: Overcome display engine stride limits via GTT remapping")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200429101034.8208-4-ville.syrjala@linux.intel.com
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
(cherry picked from commit 5331889b5f)
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Alexandre Oliva has recently removed these files from Linux Libre
with concerns that the sources weren't available.
The sources are available on IGT repository, and only open source
tools are used to generate the {ivb,hsw}_clear_kernel.c files.
However, the remaining concern from Alexandre Oliva was around
GPL license and the source not been present when distributing
the code.
So, it looks like 2 alternatives are possible, the use of
linux-firmware.git repository to store the blob or making sure
that the source is also present in our tree. Since the goal
is to limit the i915 firmware to only the micro-controller blobs
let's make sure that we do include the asm sources here in our tree.
Btw, I tried to have some diligence here and make sure that the
asms that these commits are adding are truly the source for
the mentioned files:
igt$ ./scripts/generate_clear_kernel.sh -g ivb \
-m ~/mesa/build/src/intel/tools/i965_asm
Output file not specified - using default file "ivb-cb_assembled"
Generating gen7 CB Kernel assembled file "ivb_clear_kernel.c"
for i915 driver...
igt$ diff ~/i915/drm-tip/drivers/gpu/drm/i915/gt/ivb_clear_kernel.c \
ivb_clear_kernel.c
< * Generated by: IGT Gpu Tools on Fri 21 Feb 2020 05:29:32 AM UTC
> * Generated by: IGT Gpu Tools on Mon 08 Jun 2020 10:00:54 AM PDT
61c61
< };
> };
\ No newline at end of file
igt$ ./scripts/generate_clear_kernel.sh -g hsw \
-m ~/mesa/build/src/intel/tools/i965_asm
Output file not specified - using default file "hsw-cb_assembled"
Generating gen7.5 CB Kernel assembled file "hsw_clear_kernel.c"
for i915 driver...
igt$ diff ~/i915/drm-tip/drivers/gpu/drm/i915/gt/hsw_clear_kernel.c \
hsw_clear_kernel.c
5c5
< * Generated by: IGT Gpu Tools on Fri 21 Feb 2020 05:30:13 AM UTC
> * Generated by: IGT Gpu Tools on Mon 08 Jun 2020 10:01:42 AM PDT
61c61
< };
> };
\ No newline at end of file
Used IGT and Mesa master repositories from Fri Jun 5 2020)
IGT: 53e8c878a6fb ("tests/kms_chamelium: Force reprobe after replugging
the connector")
Mesa: 5d13c7477eb1 ("radv: set keep_statistic_info with
RADV_DEBUG=shaderstats")
Mesa built with: meson build -D platforms=drm,x11 -D dri-drivers=i965 \
-D gallium-drivers=iris -D prefix=/usr \
-D libdir=/usr/lib64/ -Dtools=intel \
-Dkulkan-drivers=intel && ninja -C build
v2: Header clean-up and include build instructions in a readme (Chris)
Modified commit message to respect check-patch
Reference: http://www.fsfla.org/pipermail/linux-libre/2020-June/003374.html
Reference: http://www.fsfla.org/pipermail/linux-libre/2020-June/003375.html
Fixes: 47f8253d2b ("drm/i915/gen7: Clear all EU/L3 residual contexts")
Cc: <stable@vger.kernel.org> # v5.7+
Cc: Alexandre Oliva <lxoliva@fsfla.org>
Cc: Prathap Kumar Valsan <prathap.kumar.valsan@intel.com>
Cc: Akeem G Abodunrin <akeem.g.abodunrin@intel.com>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Reviewed-by: Jon Bloomfield <jon.bloomfield@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200610201807.191440-1-rodrigo.vivi@intel.com
(cherry picked from commit 5a7eeb8ba1)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Using _MASKED_BIT_ENABLE macro to set mask register bits is straight
forward and not likely to go wrong. However when checking which bit(s)
is(are) enabled, simply bitwise AND value and _MASKED_BIT_ENABLE() won't
output expected result. Suppose the register write is disabling bit 1
by setting 0xFFFF0000, however "& _MASKED_BIT_ENABLE(1)" outputs
0x00010000, and the non-zero check will pass which cause the old code
consider the new value set as an enabling operation.
We found guest set 0x80008000 on boot, and set 0xffff8000 during resume.
Both are legal settings but old code will block latter and force vgpu
enter fail-safe mode.
Introduce two new macro and make proper masked bit check in mmio handler:
IS_MASKED_BITS_ENABLED()
IS_MASKED_BITS_DISABLED()
V2: Rebase.
Reviewed-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Colin Xu <colin.xu@intel.com>
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20200601030721.17129-1-colin.xu@intel.com
According to BSpec the Data Island Packet should be disabled after
disabling the transcoder, but before the transcoder clock select is set
to none. On an ICL RVP, daisy-chained MST config not following this
leads to a hang with the following MCE when disabling the output:
[ 870.948739] mce: [Hardware Error]: CPU 0: Machine Check Exception: 5 Bank 6: ba00000011000402
[ 871.019212] mce: [Hardware Error]: RIP !INEXACT! 10:<ffffffff81aca652> {poll_idle+0x92/0xb0}
[ 871.019212] mce: [Hardware Error]: TSC 135a261fe61
[ 871.019212] mce: [Hardware Error]: PROCESSOR 0:706e5 TIME 1591739604 SOCKET 0 APIC 0 microcode 20
[ 871.019212] mce: [Hardware Error]: Run the above through 'mcelog --ascii'
[ 871.019212] mce: [Hardware Error]: Machine check: Processor context corrupt
[ 871.019212] Kernel panic - not syncing: Fatal machine check
[ 871.019212] Kernel Offset: disabled
Bspec: 4287
Fixes: fa37a21327 ("drm/i915: Stop sending DP SDPs on ddi disable")
Cc: Gwan-gyeong Mun <gwan-gyeong.mun@intel.com>
Cc: Uma Shankar <uma.shankar@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Uma Shankar <uma.shankar@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200609220616.6015-1-imre.deak@intel.com
(cherry picked from commit c980216dd2)
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
In commit 5ba32c7be8 ("drm/i915/execlists: Always force a context
reload when rewinding RING_TAIL"), we placed the check for rewinding a
context on actually submitting the next request in that context. This
was so that we only had to check once, and could do so with precision
avoiding as many forced restores as possible. For example, to ensure
that we can resubmit the same request a couple of times, we include a
small wa_tail such that on the next submission, the ring->tail will
appear to move forwards when resubmitting the same request. This is very
common as it will happen for every lite-restore to fill the second port
after a context switch.
However, intel_ring_direction() is limited in precision to movements of
upto half the ring size. The consequence being that if we tried to
unwind many requests, we could exceed half the ring and flip the sense
of the direction, so missing a force restore. As no request can be
greater than half the ring (i.e. 2048 bytes in the smallest case), we
can check for rollback incrementally. As we check against the tail that
would be submitted, we do not lose any sensitivity and allow lite
restores for the simple case. We still need to double check upon
submitting the context, to allow for multiple preemptions and
resubmissions.
Fixes: 5ba32c7be8 ("drm/i915/execlists: Always force a context reload when rewinding RING_TAIL")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Cc: <stable@vger.kernel.org> # v5.4+
Reviewed-by: Bruce Chang <yu.bruce.chang@intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200609151723.12971-1-chris@chris-wilson.co.uk
(cherry picked from commit e36ba817fa)
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
We have a I915_REQUEST_NOPREEMPT flag that we set when we must prevent
the HW from preempting during the course of this request. We need to
honour this flag and protect the HW even if we have a heartbeat request,
or other maximum priority barrier, pending. As such, restrict the
timeslicing check to avoid preempting into the topmost priority band,
leaving the unpreemptable requests in blissful peace running
uninterrupted on the HW.
v2: Set the I915_PRIORITY_BARRIER to be less than
I915_PRIORITY_UNPREEMPTABLE so that we never submit a request
(heartbeat or barrier) that can legitimately preempt the current
non-premptable request.
Fixes: 2a98f4e65b ("drm/i915: add infrastructure to hold off preemption on a request")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200527162418.24755-1-chris@chris-wilson.co.uk
(cherry picked from commit b72f02d78e)
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
gcc-9 gets confused by the code flow in check_dirty_whitelist:
drivers/gpu/drm/i915/gt/selftest_workarounds.c: In function 'check_dirty_whitelist':
drivers/gpu/drm/i915/gt/selftest_workarounds.c:492:17: error: 'rsvd' may be used uninitialized in this function [-Werror=maybe-uninitialized]
I could not figure out a good way to do this in a way that gcc
understands better, so initialize the variable to zero, as last
resort.
Fixes: aee20aaed8 ("drm/i915: Implement read-only support in whitelist selftest")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200527140526.1458215-2-arnd@arndb.de
(cherry picked from commit cc649a9eaf)
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Conditional spinlocks make it hard for gcc and for lockdep to
follow the code flow. This one causes a warning with at least
gcc-9 and higher:
In file included from include/linux/irq.h:14,
from drivers/gpu/drm/i915/i915_pmu.c:7:
drivers/gpu/drm/i915/i915_pmu.c: In function 'i915_sample':
include/linux/spinlock.h:289:3: error: 'flags' may be used uninitialized in this function [-Werror=maybe-uninitialized]
289 | _raw_spin_unlock_irqrestore(lock, flags); \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/i915/i915_pmu.c:288:17: note: 'flags' was declared here
288 | unsigned long flags;
| ^~~~~
Split out the part between the locks into a separate function
for readability and to let the compiler figure out what the
logic actually is.
Fixes: d79e1bd676 ("drm/i915/pmu: Only use exclusive mmio access for gen7")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20200527140526.1458215-1-arnd@arndb.de
(cherry picked from commit 6ec81b8273)
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Merge some more updates from Andrew Morton:
- various hotfixes and minor things
- hch's use_mm/unuse_mm clearnups
Subsystems affected by this patch series: mm/hugetlb, scripts, kcov,
lib, nilfs, checkpatch, lib, mm/debug, ocfs2, lib, misc.
* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
kernel: set USER_DS in kthread_use_mm
kernel: better document the use_mm/unuse_mm API contract
kernel: move use_mm/unuse_mm to kthread.c
kernel: move use_mm/unuse_mm to kthread.c
stacktrace: cleanup inconsistent variable type
lib: test get_count_order/long in test_bitops.c
mm: add comments on pglist_data zones
ocfs2: fix spelling mistake and grammar
mm/debug_vm_pgtable: fix kernel crash by checking for THP support
lib: fix bitmap_parse() on 64-bit big endian archs
checkpatch: correct check for kernel parameters doc
nilfs2: fix null pointer dereference at nilfs_segctor_do_construct()
lib/lz4/lz4_decompress.c: document deliberate use of `&'
kcov: check kcov_softirq in kcov_remote_stop()
scripts/spelling: add a few more typos
khugepaged: selftests: fix timeout condition in wait_for_scan()
Pull drm fixes from Dave Airlie:
"One sun4i fix and a connector hotplug race The ast fix is for a
regression in 5.6, and one of the i915 ones fixes an oops reported by
dhowells.
core:
- fix race in connectors sending hotplug
i915:
- Avoid use after free in cmdparser
- Avoid NULL dereference when probing all display encoders
- Fixup to module parameter type
sun4i:
- clock divider fix
ast:
- 24/32 bpp mode setting fix"
* tag 'drm-next-2020-06-11-1' of git://anongit.freedesktop.org/drm/drm:
drm/ast: fix missing break in switch statement for format->cpp[0] case 4
drm/sun4i: hdmi ddc clk: Fix size of m divider
drm/i915/display: Only query DP state of a DDI encoder
drm/i915/params: fix i915.reset module param type
drm/i915/gem: Mark the buffer pool as active for the cmdparser
drm/connector: notify userspace on hotplug after register complete
Pull i915 uaccess updates from Al Viro:
"Low-hanging fruit in i915; there are several trickier followups, but
that'll wait for the next cycle"
* 'uaccess.i915' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
i915:get_engines(): get rid of pointless access_ok()
i915: alloc_oa_regs(): get rid of pointless access_ok()
i915 compat ioctl(): just use drm_ioctl_kernel()
i915: switch copy_perf_config_registers_or_number() to unsafe_put_user()
i915: switch query_{topology,engine}_info() to copy_to_user()
Pull drm fixes from Dave Airlie:
"These are the fixes from last week for the stuff merged in the merge
window. It got a bunch of nouveau fixes for HDA audio on some new
GPUs, some i915 and some amdpgu fixes.
i915:
- gvt: Fix one clang warning on debug only function
- Use ARRAY_SIZE for coccicheck warning
- Use after free fix for display global state.
- Whitelisting context-local timestamp on Gen9 and two scheduler
fixes with deps (Cc: stable)
- Removal of write flag from sysfs files where ineffective
nouveau:
- HDMI/DP audio HDA fixes
- display hang fix for Volta/Turing
- GK20A regression fix.
amdgpu:
- Prevent hwmon accesses while GPU is in reset
- CTF interrupt fix
- Backlight fix for renoir
- Fix for display sync groups
- Display bandwidth validation workaround"
* tag 'drm-next-2020-06-08' of git://anongit.freedesktop.org/drm/drm: (28 commits)
drm/nouveau/kms/nv50-: clear SW state of disabled windows harder
drm/nouveau: gr/gk20a: Use firmware version 0
drm/nouveau/disp/gm200-: detect and potentially disable HDA support on some SORs
drm/nouveau/disp/gp100: split SOR implementation from gm200
drm/nouveau/disp: modify OR allocation policy to account for HDA requirements
drm/nouveau/disp: split part of OR allocation logic into a function
drm/nouveau/disp: provide hint to OR allocation about HDA requirements
drm/amd/display: Revalidate bandwidth before commiting DC updates
drm/amdgpu/display: use blanked rather than plane state for sync groups
drm/i915/params: fix i915.fake_lmem_start module param sysfs permissions
drm/i915/params: don't expose inject_probe_failure in debugfs
drm/i915: Whitelist context-local timestamp in the gen9 cmdparser
drm/i915: Fix global state use-after-frees with a refcount
drm/i915: Check for awaits on still currently executing requests
drm/i915/gt: Do not schedule normal requests immediately along virtual
drm/i915: Reorder await_execution before await_request
drm/nouveau/kms/gt215-: fix race with audio driver runpm
drm/nouveau/disp/gm200-: fix NV_PDISP_SOR_HDMI2_CTRL(n) selection
Revert "drm/amd/display: disable dcn20 abm feature for bring up"
drm/amd/powerplay: ack the SMUToHost interrupt on receive V2
...
If the execbuf is interrupted after building the cmdparser pipeline, and
before we commit to submitting the request to HW, we would attempt to
clean up the cmdparser early. While we held active references to the vma
being parsed and constructed, we did not hold an active reference for
the buffer pool itself. The result was that an interrupted execbuf could
still have run the cmdparser pipeline, but since the buffer pool was
idle, its target vma could have been recycled.
Note this problem only occurs if the cmdparser is running async due to
pipelined waits on busy fences, and the execbuf is interrupted.
Fixes: 686c7c35ab ("drm/i915/gem: Asynchronous cmdparser")
Fixes: 16e8745967 ("drm/i915/gt: Move the batch buffer pool from the engine to the gt")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200604103751.18816-1-chris@chris-wilson.co.uk
(cherry picked from commit 57a78ca4ec)
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Pull power management updates from Rafael Wysocki:
"These rework the system-wide PM driver flags, make runtime switching
of cpuidle governors easier, improve the user space hibernation
interface code, add intel-speed-select interface documentation, add
more debug messages to the ACPI code handling suspend to idle, update
the cpufreq core and drivers, fix a minor issue in the cpuidle core
and update two cpuidle drivers, improve the PM-runtime framework,
update the Intel RAPL power capping driver, update devfreq core and
drivers, and clean up the cpupower utility.
Specifics:
- Rework the system-wide PM driver flags to make them easier to
understand and use and update their documentation (Rafael Wysocki,
Alan Stern).
- Allow cpuidle governors to be switched at run time regardless of
the kernel configuration and update the related documentation
accordingly (Hanjun Guo).
- Improve the resume device handling in the user space hibernarion
interface code (Domenico Andreoli).
- Document the intel-speed-select sysfs interface (Srinivas
Pandruvada).
- Make the ACPI code handing suspend to idle print more debug
messages to help diagnose issues with it (Rafael Wysocki).
- Fix a helper routine in the cpufreq core and correct a typo in the
struct cpufreq_driver kerneldoc comment (Rafael Wysocki, Wang
Wenhu).
- Update cpufreq drivers:
- Make the intel_pstate driver start in the passive mode by
default on systems without HWP (Rafael Wysocki).
- Add i.MX7ULP support to the imx-cpufreq-dt driver and add
i.MX7ULP to the cpufreq-dt-platdev blacklist (Peng Fan).
- Convert the qoriq cpufreq driver to a platform one, make the
platform code create a suitable device object for it and add
platform dependencies to it (Mian Yousaf Kaukab, Geert
Uytterhoeven).
- Fix wrong compatible binding in the qcom driver (Ansuel Smith).
- Build the omap driver by default for ARCH_OMAP2PLUS (Anders
Roxell).
- Add r8a7742 SoC support to the dt cpufreq driver (Lad
Prabhakar).
- Update cpuidle core and drivers:
- Fix three reference count leaks in error code paths in the
cpuidle core (Qiushi Wu).
- Convert Qualcomm SPM to a generic cpuidle driver (Stephan
Gerhold).
- Fix up the execution order when entering a domain idle state in
the PSCI driver (Ulf Hansson).
- Fix a reference counting issue related to clock management and
clean up two oddities in the PM-runtime framework (Rafael Wysocki,
Andy Shevchenko).
- Add ElkhartLake support to the Intel RAPL power capping driver and
remove an unused local MSR definition from it (Jacob Pan, Sumeet
Pawnikar).
- Update devfreq core and drivers:
- Replace strncpy() with strscpy() in the devfreq core and use
lockdep asserts instead of manual checks for a locked mutex in
it (Dmitry Osipenko, Krzysztof Kozlowski).
- Add a generic imx bus scaling driver and make it register an
interconnect device (Leonard Crestez, Gustavo A. R. Silva).
- Make the cpufreq notifier in the tegra30 driver take boosting
into account and delete an unuseful error message from that
driver (Dmitry Osipenko, Markus Elfring).
- Remove unneeded semicolon from the cpupower code (Zou Wei)"
* tag 'pm-5.8-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (51 commits)
cpuidle: Fix three reference count leaks
PM: runtime: Replace pm_runtime_callbacks_present()
PM / devfreq: Use lockdep asserts instead of manual checks for locked mutex
PM / devfreq: imx-bus: Fix inconsistent IS_ERR and PTR_ERR
PM / devfreq: Replace strncpy with strscpy
PM / devfreq: imx: Register interconnect device
PM / devfreq: Add generic imx bus scaling driver
PM / devfreq: tegra30: Delete an error message in tegra_devfreq_probe()
PM / devfreq: tegra30: Make CPUFreq notifier to take into account boosting
PM: hibernate: Restrict writes to the resume device
PM: runtime: clk: Fix clk_pm_runtime_get() error path
cpuidle: Convert Qualcomm SPM driver to a generic CPUidle driver
ACPI: EC: PM: s2idle: Extend GPE dispatching debug message
ACPI: PM: s2idle: Print type of wakeup debug messages
powercap: RAPL: remove unused local MSR define
PM: runtime: Make clear what we do when conditions are wrong in rpm_suspend()
Documentation: admin-guide: pm: Document intel-speed-select
PM: hibernate: Split off snapshot dev option
PM: hibernate: Incorporate concurrency handling
Documentation: ABI: make current_governer_ro as a candidate for removal
...
Merge updates from Andrew Morton:
"A few little subsystems and a start of a lot of MM patches.
Subsystems affected by this patch series: squashfs, ocfs2, parisc,
vfs. With mm subsystems: slab-generic, slub, debug, pagecache, gup,
swap, memcg, pagemap, memory-failure, vmalloc, kasan"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (128 commits)
kasan: move kasan_report() into report.c
mm/mm_init.c: report kasan-tag information stored in page->flags
ubsan: entirely disable alignment checks under UBSAN_TRAP
kasan: fix clang compilation warning due to stack protector
x86/mm: remove vmalloc faulting
mm: remove vmalloc_sync_(un)mappings()
x86/mm/32: implement arch_sync_kernel_mappings()
x86/mm/64: implement arch_sync_kernel_mappings()
mm/ioremap: track which page-table levels were modified
mm/vmalloc: track which page-table levels were modified
mm: add functions to track page directory modifications
s390: use __vmalloc_node in stack_alloc
powerpc: use __vmalloc_node in alloc_vm_stack
arm64: use __vmalloc_node in arch_alloc_vmap_stack
mm: remove vmalloc_user_node_flags
mm: switch the test_vmalloc module to use __vmalloc_node
mm: remove __vmalloc_node_flags_caller
mm: remove both instances of __vmalloc_node_flags
mm: remove the prot argument to __vmalloc_node
mm: remove the pgprot argument to __vmalloc
...
Doing a "get_user_pages()" on a copy-on-write page for reading can be
ambiguous: the page can be COW'ed at any time afterwards, and the
direction of a COW event isn't defined.
Yes, whoever writes to it will generally do the COW, but if the thread
that did the get_user_pages() unmapped the page before the write (and
that could happen due to memory pressure in addition to any outright
action), the writer could also just take over the old page instead.
End result: the get_user_pages() call might result in a page pointer
that is no longer associated with the original VM, and is associated
with - and controlled by - another VM having taken it over instead.
So when doing a get_user_pages() on a COW mapping, the only really safe
thing to do would be to break the COW when getting the page, even when
only getting it for reading.
At the same time, some users simply don't even care.
For example, the perf code wants to look up the page not because it
cares about the page, but because the code simply wants to look up the
physical address of the access for informational purposes, and doesn't
really care about races when a page might be unmapped and remapped
elsewhere.
This adds logic to force a COW event by setting FOLL_WRITE on any
copy-on-write mapping when FOLL_GET (or FOLL_PIN) is used to get a page
pointer as a result.
The current semantics end up being:
- __get_user_pages_fast(): no change. If you don't ask for a write,
you won't break COW. You'd better know what you're doing.
- get_user_pages_fast(): the fast-case "look it up in the page tables
without anything getting mmap_sem" now refuses to follow a read-only
page, since it might need COW breaking. Which happens in the slow
path - the fast path doesn't know if the memory might be COW or not.
- get_user_pages() (including the slow-path fallback for gup_fast()):
for a COW mapping, turn on FOLL_WRITE for FOLL_GET/FOLL_PIN, with
very similar semantics to FOLL_FORCE.
If it turns out that we want finer granularity (ie "only break COW when
it might actually matter" - things like the zero page are special and
don't need to be broken) we might need to push these semantics deeper
into the lookup fault path. So if people care enough, it's possible
that we might end up adding a new internal FOLL_BREAK_COW flag to go
with the internal FOLL_COW flag we already have for tracking "I had a
COW".
Alternatively, if it turns out that different callers might want to
explicitly control the forced COW break behavior, we might even want to
make such a flag visible to the users of get_user_pages() instead of
using the above default semantics.
But for now, this is mostly commentary on the issue (this commit message
being a lot bigger than the patch, and that patch in turn is almost all
comments), with that minimal "enable COW breaking early" logic using the
existing FOLL_WRITE behavior.
[ It might be worth noting that we've always had this ambiguity, and it
could arguably be seen as a user-space issue.
You only get private COW mappings that could break either way in
situations where user space is doing cooperative things (ie fork()
before an execve() etc), but it _is_ surprising and very subtle, and
fork() is supposed to give you independent address spaces.
So let's treat this as a kernel issue and make the semantics of
get_user_pages() easier to understand. Note that obviously a true
shared mapping will still get a page that can change under us, so this
does _not_ mean that get_user_pages() somehow returns any "stable"
page ]
Reported-by: Jann Horn <jannh@google.com>
Tested-by: Christoph Hellwig <hch@lst.de>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Kirill Shutemov <kirill@shutemov.name>
Acked-by: Jan Kara <jack@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
While the current locking/serialization of the global state
suffices for protecting the obj->state access and the actual
hardware reprogramming, we do have a problem with accessing
the old/new states during nonblocking commits.
The state computation and swap will be protected by the crtc
locks, but the commit_tails can finish out of order, thus also
causing the atomic states to be cleaned up out of order. This
would mean the commit that started first but finished last has
had its new state freed as the no-longer-needed old state by the
other commit.
To fix this let's just refcount the states. obj->state amounts
to one reference, and the intel_atomic_state holds extra references
to both its new and old global obj states.
Fixes: 0ef1905ecf ("drm/i915: Introduce better global state handling")
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200527200245.13184-1-ville.syrjala@linux.intel.com
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>
(cherry picked from commit f8c86ffa28)
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Pull uaccess/readdir updates from Al Viro:
"Finishing the conversion of readdir.c to unsafe_... API.
This includes the uaccess_{read,write}_begin series by Christophe
Leroy"
* 'uaccess.readdir' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
readdir.c: get rid of the last __put_user(), drop now-useless access_ok()
readdir.c: get compat_filldir() more or less in sync with filldir()
switch readdir(2) to unsafe_copy_dirent_name()
drm/i915/gem: Replace user_access_begin by user_write_access_begin
uaccess: Selectively open read or write user access
uaccess: Add user_read_access_begin/end and user_write_access_begin/end
