kernel.git/arch/powerpc/kernel/setup_64.c, branch linux-4.16.y

powerpc/64s: Default l1d_size to 64K in RFI fallback flush

2018-06-20T19:01:17Z

[ Upstream commit 9dfbf78e4114fcaf4ef61c49885c3ab5bad40d0b ] If there is no d-cache-size property in the device tree, l1d_size could be zero. We don't actually expect that to happen, it's only been seen on mambo (simulator) in some configurations. A zero-size l1d_size leads to the loop in the asm wrapping around to 2^64-1, and then walking off the end of the fallback area and eventually causing a page fault which is fatal. Just default to 64K which is correct on some CPUs, and sane enough to not cause a crash on others. Fixes: aa8a5e0062ac9 ('powerpc/64s: Add support for RFI flush of L1-D cache') Signed-off-by: Madhavan Srinivasan [mpe: Rewrite comment and change log] Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

powerpc/64s: Move cpu_show_meltdown()

2018-05-25T14:46:05Z

commit 8ad33041563a10b34988800c682ada14b2612533 upstream. This landed in setup_64.c for no good reason other than we had nowhere else to put it. Now that we have a security-related file, that is a better place for it so move it. Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

powerpc/64s: Improve RFI L1-D cache flush fallback

2018-01-23T05:16:33Z

The fallback RFI flush is used when firmware does not provide a way to flush the cache. It's a "displacement flush" that evicts useful data by displacing it with an uninteresting buffer. The flush has to take care to work with implementation specific cache replacment policies, so the recipe has been in flux. The initial slow but conservative approach is to touch all lines of a congruence class, with dependencies between each load. It has since been determined that a linear pattern of loads without dependencies is sufficient, and is significantly faster. Measuring the speed of a null syscall with RFI fallback flush enabled gives the relative improvement: P8 - 1.83x P9 - 1.75x The flush also becomes simpler and more adaptable to different cache geometries. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman

Merge branch 'fixes' into next

2018-01-21T12:21:14Z

Merge our fixes branch from the 4.15 cycle. Unusually the fixes branch saw some significant features merged, notably the RFI flush patches, so we want the code in next to be tested against that, to avoid any surprises when the two are merged. There's also some other work on the panic handling that was reverted in fixes and we now want to do properly in next, which would conflict. And we also fix a few other minor merge conflicts.

powerpc/64: Rename soft_enabled to irq_soft_mask

2018-01-19T11:37:01Z

Rename the paca->soft_enabled to paca->irq_soft_mask as it is no longer used as a flag for interrupt state, but a mask. Signed-off-by: Madhavan Srinivasan Signed-off-by: Michael Ellerman

powerpc/64: Move set_soft_enabled() and rename

2018-01-19T11:36:58Z

Move set_soft_enabled() from powerpc/kernel/irq.c to asm/hw_irq.c, to encourage updates to paca->soft_enabled done via these access function. Add "memory" clobber to hint compiler since paca->soft_enabled memory is the target here. Renaming it as soft_enabled_set() will make namespaces works better as prefix than a postfix when new soft_enabled manipulation functions are introduced. Reviewed-by: Nicholas Piggin Signed-off-by: Madhavan Srinivasan Signed-off-by: Michael Ellerman

powerpc/64: Add #defines for paca->soft_enabled flags

2018-01-19T11:36:56Z

Two #defines IRQS_ENABLED and IRQS_DISABLED are added to be used when updating paca->soft_enabled. Replace the hardcoded values used when updating paca->soft_enabled with IRQ_(EN|DIS)ABLED #define. No logic change. Reviewed-by: Nicholas Piggin Signed-off-by: Madhavan Srinivasan Signed-off-by: Michael Ellerman

powerpc/64s: Relax PACA address limitations

2018-01-18T04:42:48Z

Book3S PACA memory allocation is restricted by the RMA limit and also must not take SLB faults when accessed in virtual mode. Currently a fixed 256MB limit is used for this, which is imprecise and sub-optimal. Update the paca allocation limits to use use the ppc64_rma_size for RMA limit, and share the safe_stack_limit() that is currently used for stack allocations that must not take virtual mode faults. The safe_stack_limit() name is changed to ppc64_bolted_size() to match ppc64_rma_size and some comments are updated. We also need to use early_mmu_has_feature() because we are now calling this function prior to the jump label patching that enables mmu_has_feature(). Signed-off-by: Nicholas Piggin [mpe: Change mmu_has_feature() to early_mmu_has_feature()] Signed-off-by: Michael Ellerman

powerpc/64s: Allow control of RFI flush via debugfs

2018-01-17T12:30:21Z

Expose the state of the RFI flush (enabled/disabled) via debugfs, and allow it to be enabled/disabled at runtime. eg: $ cat /sys/kernel/debug/powerpc/rfi_flush 1 $ echo 0 > /sys/kernel/debug/powerpc/rfi_flush $ cat /sys/kernel/debug/powerpc/rfi_flush 0 Signed-off-by: Michael Ellerman Reviewed-by: Nicholas Piggin

powerpc/64s: Wire up cpu_show_meltdown()

2018-01-17T12:30:20Z

The recent commit 87590ce6e373 ("sysfs/cpu: Add vulnerability folder") added a generic folder and set of files for reporting information on CPU vulnerabilities. One of those was for meltdown: /sys/devices/system/cpu/vulnerabilities/meltdown This commit wires up that file for 64-bit Book3S powerpc. For now we default to "Vulnerable" unless the RFI flush is enabled. That may not actually be true on all hardware, further patches will refine the reporting based on the CPU/platform etc. But for now we default to being pessimists. Signed-off-by: Michael Ellerman