user/sven/linux.git/arch/powerpc/kernel/setup_64.c, branch v4.9.147

powerpc/64s: Fix section mismatch warnings from setup_rfi_flush()

2018-06-06T14:44:37Z

commit 501a78cbc17c329fabf8e9750a1e9ab810c88a0e upstream. The recent LPM changes to setup_rfi_flush() are causing some section mismatch warnings because we removed the __init annotation on setup_rfi_flush(): The function setup_rfi_flush() references the function __init ppc64_bolted_size(). the function __init memblock_alloc_base(). The references are actually in init_fallback_flush(), but that is inlined into setup_rfi_flush(). These references are safe because: - only pseries calls setup_rfi_flush() at runtime - pseries always passes L1D_FLUSH_FALLBACK at boot - so the fallback flush area will always be allocated - so the check in init_fallback_flush() will always return early: /* Only allocate the fallback flush area once (at boot time). */ if (l1d_flush_fallback_area) return; - and therefore we won't actually call the freed init routines. We should rework the code to make it safer by default rather than relying on the above, but for now as a quick-fix just add a __ref annotation to squash the warning. Fixes: abf110f3e1ce ("powerpc/rfi-flush: Make it possible to call setup_rfi_flush() again") Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

powerpc/64s: Move cpu_show_meltdown()

2018-06-06T14:44:36Z

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. [mpe: Add extern for rfi_flush to fix bisection break] Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

powerpc/rfi-flush: Differentiate enabled and patched flush types

2018-06-06T14:44:35Z

commit 0063d61ccfc011f379a31acaeba6de7c926fed2c upstream. Currently the rfi-flush messages print 'Using flush' for all enabled_flush_types, but that is not necessarily true -- as now the fallback flush is always enabled on pseries, but the fixup function overwrites its nop/branch slot with other flush types, if available. So, replace the 'Using flush' messages with ' flush is available'. Also, print the patched flush types in the fixup function, so users can know what is (not) being used (e.g., the slower, fallback flush, or no flush type at all if flush is disabled via the debugfs switch). Suggested-by: Michael Ellerman Signed-off-by: Mauricio Faria de Oliveira Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

powerpc/rfi-flush: Make it possible to call setup_rfi_flush() again

2018-06-06T14:44:35Z

commit abf110f3e1cea40f5ea15e85f5d67c39c14568a7 upstream. For PowerVM migration we want to be able to call setup_rfi_flush() again after we've migrated the partition. To support that we need to check that we're not trying to allocate the fallback flush area after memblock has gone away (i.e., boot-time only). Signed-off-by: Michael Ellerman Signed-off-by: Mauricio Faria de Oliveira Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

powerpc/rfi-flush: Move the logic to avoid a redo into the debugfs code

2018-06-06T14:44:35Z

commit 1e2a9fc7496955faacbbed49461d611b704a7505 upstream. rfi_flush_enable() includes a check to see if we're already enabled (or disabled), and in that case does nothing. But that means calling setup_rfi_flush() a 2nd time doesn't actually work, which is a bit confusing. Move that check into the debugfs code, where it really belongs. Signed-off-by: Michael Ellerman Signed-off-by: Mauricio Faria de Oliveira Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

powerpc/rfi-flush: Move out of HARDLOCKUP_DETECTOR #ifdef

2018-06-06T14:44:35Z

The backport of the RFI flush support, done by me, has a minor bug in that the code is inside an #ifdef CONFIG_HARDLOCKUP_DETECTOR, which is incorrect. This doesn't matter with common configs because we enable HARDLOCKUP_DETECTOR, but with future patches it will break the build. So fix it. Fixes: c3b82ebee6e0 ("powerpc/64s: Add support for RFI flush of L1-D cache") Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

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

2018-02-25T10:05:50Z

commit bdcb1aefc5b3f7d0f1dc8b02673602bca2ff7a4b upstream. 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 [mpe: Backport to 4.9] Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

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

2018-02-13T11:35:55Z

commit 236003e6b5443c45c18e613d2b0d776a9f87540e upstream. 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 Signed-off-by: Greg Kroah-Hartman

powerpc/64s: Wire up cpu_show_meltdown()

2018-02-13T11:35:55Z

commit fd6e440f20b1a4304553775fc55938848ff617c9 upstream. 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 Signed-off-by: Greg Kroah-Hartman

powerpc/64s: Support disabling RFI flush with no_rfi_flush and nopti

2018-02-13T11:35:54Z

commit bc9c9304a45480797e13a8e1df96ffcf44fb62fe upstream. Because there may be some performance overhead of the RFI flush, add kernel command line options to disable it. We add a sensibly named 'no_rfi_flush' option, but we also hijack the x86 option 'nopti'. The RFI flush is not the same as KPTI, but if we see 'nopti' we can guess that the user is trying to avoid any overhead of Meltdown mitigations, and it means we don't have to educate every one about a different command line option. Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman