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authorJani Nikula <jani.nikula@intel.com>2017-02-01 15:46:09 +0200
committerJani Nikula <jani.nikula@intel.com>2017-02-08 13:10:36 +0200
commit853277481178fdf14d1a4e9e6ac7174d6046176f (patch)
treee657b885610527c8359fc2c6f4a11a7fa8958150 /net/ipv4/ip_options.c
parent7152187159193056f30ad5726741bb25028672bf (diff)
drm/i915: don't warn about Skylake CPU - KabyPoint PCH combo
Apparently there are machines out there with Skylake CPU and KabyPoint PCH. Judging from our driver code, there doesn't seem to be any code paths that would do anything different between SunrisePoint and KabyPoint PCHs, so it would seem okay to accept the combo without warnings. Fixes: 22dea0be50b2 ("drm/i915: Introduce Kabypoint PCH for Kabylake H/DT.") References: https://lists.freedesktop.org/archives/intel-gfx/2017-February/118611.html Reported-by: Rainer Koenig <Rainer.Koenig@ts.fujitsu.com> Cc: Rainer Koenig <Rainer.Koenig@ts.fujitsu.com> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com> Cc: <stable@vger.kernel.org> # v4.8+ Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com> Signed-off-by: Jani Nikula <jani.nikula@intel.com> Link: http://patchwork.freedesktop.org/patch/msgid/1485956769-26015-1-git-send-email-jani.nikula@intel.com (cherry picked from commit 3aac4acb89710fe782c9e78e7b1febf76e112c6c) Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Diffstat (limited to 'net/ipv4/ip_options.c')
0 files changed, 0 insertions, 0 deletions
generated by cgit v1.2.3-54-g00ecf (git 2.39.0) at 2024-10-23 09:39:32 +0000
%g3 or %g3, 0x7c, %g3 wrpr %g3, %tnpc done All window trap handlers are 0x80 aligned, so if we "or" 0x7c into the trap time program counter, we'll get that final instruction in the trap handler. On return from trap, we have to pull the register window in but we do this by hand instead of just executing a "restore" instruction for several reasons. The largest being that from Niagara and onward we simply don't have enough levels in the trap stack to fully resolve all possible exception cases of a window fault when we are already at trap level 1 (which we enter to get ready to return from the original trap). This is executed inline via the FILL_*_RTRAP handlers. rtrap_64.S's code branches directly to these to do the window fill by hand if necessary. Now if you look at them, we'll see at the end: ba,a,pt %xcc, user_rtt_fill_fixup; ba,a,pt %xcc, user_rtt_fill_fixup; ba,a,pt %xcc, user_rtt_fill_fixup; And oops, all three cases are handled like a fault. This doesn't work because each of these trap types (data access exception, memory address unaligned, and faults) store their auxiliary info in different registers to pass on to the C handler which does the real work. So in the case where the stack was unaligned, the unaligned trap handler sets up the arg registers one way, and then we branched to the fault handler which expects them setup another way. So the FAULT_TYPE_* value ends up basically being garbage, and randomly would generate the backtrace seen above. Reported-by: Nick Alcock <nix@esperi.org.uk> Signed-off-by: David S. Miller <davem@davemloft.net>
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