kernel/arch/powerpc/include/asm/security_features.h, branch linux-4.16.y

powerpc/64s: Add support for a store forwarding barrier at kernel entry/exit

2018-05-25T14:46:06Z

commit a048a07d7f4535baa4cbad6bc024f175317ab938 upstream. On some CPUs we can prevent a vulnerability related to store-to-load forwarding by preventing store forwarding between privilege domains, by inserting a barrier in kernel entry and exit paths. This is known to be the case on at least Power7, Power8 and Power9 powerpc CPUs. Barriers must be inserted generally before the first load after moving to a higher privilege, and after the last store before moving to a lower privilege, HV and PR privilege transitions must be protected. Barriers are added as patch sections, with all kernel/hypervisor entry points patched, and the exit points to lower privilge levels patched similarly to the RFI flush patching. Firmware advertisement is not implemented yet, so CPU flush types are hard coded. Thanks to Michal Suchánek for bug fixes and review. Signed-off-by: Nicholas Piggin Signed-off-by: Mauricio Faria de Oliveira Signed-off-by: Michael Neuling Signed-off-by: Michal Suchánek Signed-off-by: Michael Ellerman Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

powerpc: Move default security feature flags

2018-05-25T14:46:06Z

commit e7347a86830f38dc3e40c8f7e28c04412b12a2e7 upstream. This moves the definition of the default security feature flags (i.e., enabled by default) closer to the security feature flags. This can be used to restore current flags to the default flags. Signed-off-by: Mauricio Faria de Oliveira Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

powerpc/64s: Enhance the information in cpu_show_meltdown()

2018-05-25T14:46:05Z

commit ff348355e9c72493947be337bb4fae4fc1a41eba upstream. Now that we have the security feature flags we can make the information displayed in the "meltdown" file more informative. Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

powerpc: Add security feature flags for Spectre/Meltdown

2018-05-25T14:46:04Z

commit 9a868f634349e62922c226834aa23e3d1329ae7f upstream. This commit adds security feature flags to reflect the settings we receive from firmware regarding Spectre/Meltdown mitigations. The feature names reflect the names we are given by firmware on bare metal machines. See the hostboot source for details. Arguably these could be firmware features, but that then requires them to be read early in boot so they're available prior to asm feature patching, but we don't actually want to use them for patching. We may also want to dynamically update them in future, which would be incompatible with the way firmware features work (at the moment at least). So for now just make them separate flags. Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman