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由 Arnd Bergmann 提交于
Commit d015fe99 'powerpc/cell/axon-msi: Retry on missing interrupt' has turned a rare failure to kexec on QS22 into a reproducible error, which we have now analysed. The problem is that after a kexec, the MSIC hardware still points into the middle of the old ring buffer. We set up the ring buffer during reboot, but not the offset into it. On older kernels, this would cause a storm of thousands of spurious interrupts after a kexec, which would most of the time get dropped silently. With the new code, we time out on each interrupt, waiting for it to become valid. If more interrupts come in that we time out on, this goes on indefinitely, which eventually leads to a hard crash. The solution in this commit is to read the current offset from the MSIC when reinitializing it. This now works correctly, as expected. Reported-by: NDirk Herrendoerfer <d.herrendoerfer@de.ibm.com> Signed-off-by: NArnd Bergmann <arnd@arndb.de> Acked-by: NMichael Ellerman <michael@ellerman.id.au> Signed-off-by: NPaul Mackerras <paulus@samba.org>
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