Please apply commit 0828137e8f16 ("powerpc/64s: Don't init FSCR_DSCR in __init_FSCR()") to v4.14.y, v4.19.y, v5.4.y, v5.7.y
After commit 912c0a7f2b5daa3cbb2bc10f303981e493de73bd ("powerpc/64s: Save FSCR to init_task.thread.fscr after feature init"), which has been applied to the referred branches, when userspace sets the user DSCR MSR, it won't be inherited or restored during context switch, because the facility unavailable interrupt won't trigger.
Applying 0828137e8f16721842468e33df0460044a0c588b ("powerpc/64s: Don't init FSCR_DSCR in __init_FSCR()") will fix it.
Cascardo.
On Tue, Aug 25, 2020 at 07:44:08PM -0300, Thadeu Lima de Souza Cascardo wrote:
After commit 912c0a7f2b5daa3cbb2bc10f303981e493de73bd ("powerpc/64s: Save FSCR to init_task.thread.fscr after feature init"), which has been applied to the referred branches, when userspace sets the user DSCR MSR, it won't be inherited or restored during context switch, because the facility unavailable interrupt won't trigger.
Applying 0828137e8f16721842468e33df0460044a0c588b ("powerpc/64s: Don't init FSCR_DSCR in __init_FSCR()") will fix it.
Now queued up, thanks.
greg k-h
Greg KH gregkh@linuxfoundation.org writes:
On Tue, Aug 25, 2020 at 07:44:08PM -0300, Thadeu Lima de Souza Cascardo wrote:
After commit 912c0a7f2b5daa3cbb2bc10f303981e493de73bd ("powerpc/64s: Save FSCR to init_task.thread.fscr after feature init"), which has been applied to the referred branches, when userspace sets the user DSCR MSR, it won't be inherited or restored during context switch, because the facility unavailable interrupt won't trigger.
Applying 0828137e8f16721842468e33df0460044a0c588b ("powerpc/64s: Don't init FSCR_DSCR in __init_FSCR()") will fix it.
Oops, thanks for catching it.
Acked-by: Michael Ellerman mpe@ellerman.id.au
Now queued up, thanks.
Thanks.
cheers
linux-stable-mirror@lists.linaro.org
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Greg KH -
Michael Ellerman -
Thadeu Lima de Souza Cascardo