Skip to content

L
linux
Switch branch/tag
  1. 06 Aug, 2015 37 commits
  3. 05 Aug, 2015 3 commits
    • Grigori Goronzy's avatar
      drm/radeon: fix HDP flushing · 8b72decc
      Grigori Goronzy authored 
      commit 54e03986 upstream.

This was regressed by commit 39e7f6f8, although I don't know of any
actual issues caused by it.

The storage domain is read without TTM locking now, but the lock
never helped to prevent any races.
Reviewed-by: default avatarChristian König <christian.koenig@amd.com>
Signed-off-by: default avatarGrigori Goronzy <greg@chown.ath.cx>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      8b72decc
    • Ian Munsie's avatar
      cxl: Fix off by one error allowing subsequent mmap page to be accessed · 8c980662
      Ian Munsie authored 
      commit 10a5894f upstream.

It was discovered that if a process mmaped their problem state area they
were able to access one page more than expected, potentially allowing
them to access the problem state area of an unrelated process.

This was due to a simple off by one error in the mmap fault handler
introduced in 0712dc7e ("cxl: Fix issues
when unmapping contexts"), which is fixed in this patch.

Fixes: 0712dc7e ("cxl: Fix issues when unmapping contexts")
Signed-off-by: default avatarIan Munsie <imunsie@au1.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      8c980662
    • Shreyas B. Prabhu's avatar
      powerpc/powernv: Fix race in updating core_idle_state · 55fbd98c
      Shreyas B. Prabhu authored 
      commit b32aadc1 upstream.

core_idle_state is maintained for each core. It uses 0-7 bits to track
whether a thread in the core has entered fastsleep or winkle. 8th bit is
used as a lock bit.
The lock bit is set in these 2 scenarios-
 - The thread is first in subcore to wakeup from sleep/winkle.
 - If its the last thread in the core about to enter sleep/winkle

While the lock bit is set, if any other thread in the core wakes up, it
loops until the lock bit is cleared before proceeding in the wakeup
path. This helps prevent race conditions w.r.t fastsleep workaround and
prevents threads from switching to process context before core/subcore
resources are restored.

But, in the path to sleep/winkle entry, we currently don't check for
lock-bit. This exposes us to following race when running with subcore
on-

First thread in the subcorea		Another thread in the same
waking up		   		core entering sleep/winkle

lwarx   r15,0,r14
ori     r15,r15,PNV_CORE_IDLE_LOCK_BIT
stwcx.  r15,0,r14
[Code to restore subcore state]

						lwarx   r15,0,r14
						[clear thread bit]
						stwcx.  r15,0,r14

andi.   r15,r15,PNV_CORE_IDLE_THREAD_BITS
stw     r15,0(r14)

Here, after the thread entering sleep clears its thread bit in
core_idle_state, the value is overwritten by the thread waking up.
In such cases when the core enters fastsleep, code mistakes an idle
thread as running. Because of this, the first thread waking up from
fastsleep which is supposed to resync timebase skips it. So we can
end up having a core with stale timebase value.

This patch fixes the above race by looping on the lock bit even while
entering the idle states.
Signed-off-by: default avatarShreyas B. Prabhu <shreyas@linux.vnet.ibm.com>
Fixes: 7b54e9f213f76 'powernv/powerpc: Add winkle support for offline cpus'
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Signed-off-by: default avatarKamal Mostafa <kamal@canonical.com>
      55fbd98c
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7