powerpc/pseries/le: Work around a firmware quirk
authorNicholas Piggin <npiggin@gmail.com>
Wed, 5 Jul 2017 03:56:26 +0000 (13:56 +1000)
committerMichael Ellerman <mpe@ellerman.id.au>
Thu, 31 Aug 2017 04:26:02 +0000 (14:26 +1000)
commitbded0706434dd34fe9d39a8f1bbb518154cacd7f
tree6ee5925c92b291c104f242d9cc975d7b23713cf1
parenta3b2cb30f252b21a6f962e0dd107c8b897ca65e4
powerpc/pseries/le: Work around a firmware quirk

Some PowerVM firmware when delivering a system reset interrupt to a
little endian OS will mess up SRR registers. They are byteswapped, and
SRR1 is incorrect. An example from a crash:

  NIP: 14dd0900000000c0
  MSR: 1000000200000080

It's possible to detect this pattern in SRR1 (that would never happen
in normal operation), and at least fix the NIP. After this patch, the
same interrupt reports NIP properly:

  NIP [c00000000009dd14] plpar_hcall_norets+0x1c/0x28

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
arch/powerpc/platforms/pseries/ras.c