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Paul Mackerras authored
Currently, if the kernel is running on a POWER9 processor under a hypervisor, it will try to use the radix MMU even though it doesn't have the necessary code to use radix under a hypervisor (it doesn't negotiate use of radix, and it doesn't do the H_REGISTER_PROC_TBL hcall). The result is that the guest kernel will crash when it tries to turn on the MMU. This fixes it by looking for the /chosen/ibm,architecture-vec-5 property, and if it exists, clears the radix MMU feature bit, before we decide whether to initialize for radix or HPT. This property is created by the hypervisor as a result of the guest calling the ibm,client-architecture-support method to indicate its capabilities, so it will indicate whether the hypervisor agreed to us using radix. Systems without a hypervisor may have this property also (for example, skiboot creates it), so we check the HV bit in the MSR to see whether we are running as a guest or not. If we are in hypervisor mode, then we can do whatever we like including using the radix MMU. The reason for using this property is that in future, when we have support for using radix under a hypervisor, we will need to check this property to see whether the hypervisor agreed to us using radix. Fixes: 2bfd65e4 ("powerpc/mm/radix: Add radix callbacks for early init routines") Cc: stable@vger.kernel.org # v4.7+ Signed-off-by:
Paul Mackerras <paulus@ozlabs.org> Signed-off-by:
Michael Ellerman <mpe@ellerman.id.au>
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