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| author | Nicholas Piggin <npiggin@gmail.com> | 2018-03-26 18:01:03 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2018-03-31 16:47:45 +0300 |
| commit | 15b4dd7981496f51c5f9262a5e0761e48de6655f (patch) | |
| tree | 0d8b46aedcc3ab85da18ee89c77b32defcd5114d /arch/powerpc/include/asm/pmac_feature.h | |
| parent | f0295e047fcf52ccb42561fb7de6942f5201b676 (diff) | |
| download | linux-15b4dd7981496f51c5f9262a5e0761e48de6655f.tar.xz | |
powerpc/64s: return more carefully from sreset NMI
System Reset, being an NMI, must return more carefully than other
interrupts. It has traditionally returned via the nromal return
from exception path, but that has a number of problems.
- r13 does not get restored if returning to kernel. This is for
interrupts which may cause a context switch, which sreset will
never do. Interrupting OPAL (which uses a different r13) is one
place where this causes breakage.
- It may cause several other problems returning to kernel with
preempt or TIF_EMULATE_STACK_STORE if it hits at the wrong time.
It's safer just to have a simple restore and return, like machine
check which is the other NMI.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/include/asm/pmac_feature.h')
0 files changed, 0 insertions, 0 deletions