kernel/arch/powerpc/include/asm/setup.h, branch linux-4.1.y

powerpc/64s: Add support for RFI flush of L1-D cache

2018-03-01T03:09:48Z

[ Upstream commit aa8a5e0062ac940f7659394f4817c948dc8c0667 ] On some CPUs we can prevent the Meltdown vulnerability by flushing the L1-D cache on exit from kernel to user mode, and from hypervisor to guest. This is known to be the case on at least Power7, Power8 and Power9. At this time we do not know the status of the vulnerability on other CPUs such as the 970 (Apple G5), pasemi CPUs (AmigaOne X1000) or Freescale CPUs. As more information comes to light we can enable this, or other mechanisms on those CPUs. The vulnerability occurs when the load of an architecturally inaccessible memory region (eg. userspace load of kernel memory) is speculatively executed to the point where its result can influence the address of a subsequent speculatively executed load. In order for that to happen, the first load must hit in the L1, because before the load is sent to the L2 the permission check is performed. Therefore if no kernel addresses hit in the L1 the vulnerability can not occur. We can ensure that is the case by flushing the L1 whenever we return to userspace. Similarly for hypervisor vs guest. In order to flush the L1-D cache on exit, we add a section of nops at each (h)rfi location that returns to a lower privileged context, and patch that with some sequence. Newer firmwares are able to advertise to us that there is a special nop instruction that flushes the L1-D. If we do not see that advertised, we fall back to doing a displacement flush in software. For guest kernels we support migration between some CPU versions, and different CPUs may use different flush instructions. So that we are prepared to migrate to a machine with a different flush instruction activated, we may have to patch more than one flush instruction at boot if the hypervisor tells us to. In the end this patch is mostly the work of Nicholas Piggin and Michael Ellerman. However a cast of thousands contributed to analysis of the issue, earlier versions of the patch, back ports testing etc. Many thanks to all of them. Tested-by: Jon Masters Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Signed-off-by: Sasha Levin

powerpc: Replace mem_init_done with slab_is_available()

2015-04-10T10:02:48Z

We have a powerpc specific global called mem_init_done which is "set on boot once kmalloc can be called". But that's not *quite* true. We set it at the bottom of mem_init(), and rely on the fact that mm_init() calls kmem_cache_init() immediately after that, and nothing is running in parallel. So replace it with the generic and 100% correct slab_is_available(). Signed-off-by: Michael Ellerman

powerpc: Remove bootmem allocator

2014-11-09T22:59:25Z

At the moment we transition from the memblock alloctor to the bootmem allocator. Gitting rid of the bootmem allocator removes a bunch of complicated code (most of which I owe the dubious honour of being responsible for writing). Signed-off-by: Anton Blanchard Tested-by: Emil Medve Signed-off-by: Michael Ellerman

powerpc: Clean up panic_timeout usage

2013-11-26T11:12:28Z

Default CONFIG_PANIC_TIMEOUT to 180 seconds on powerpc. The pSeries continue to set the timeout to 10 seconds at run-time. Thus, there's a small window where we don't have the correct value on pSeries, but if this is only run-time discoverable we don't have a better option. In any case, if the user changes the default setting of 180 seconds, we honor that user setting. Signed-off-by: Jason Baron Cc: benh@kernel.crashing.org Cc: paulus@samba.org Cc: ralf@linux-mips.org Cc: mpe@ellerman.id.au Cc: felipe.contreras@gmail.com Cc: linuxppc-dev@lists.ozlabs.org Cc: Linus Torvalds Cc: Andrew Morton Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/705bbe0f70fb20759151642ba0176a6414ec9f7a.1385418410.git.jbaron@akamai.com Signed-off-by: Ingo Molnar

powerpc: Move local setup.h declarations to arch includes

2013-10-30T05:00:31Z

Move the few declarations from arch/powerpc/kernel/setup.h into arch/powerpc/include/asm/setup.h. This resolves a sparse warning for arch/powerpc/mm/numa.c which defines do_init_bootmem() but can't include the setup.h header in the prior path. Resolves: arch/powerpc/mm/numa.c:998:13: warning: symbol 'do_init_bootmem' was not declared. Should it be static? Signed-off-by: Robert C Jennings Signed-off-by: Benjamin Herrenschmidt

powerpc: Remove stale function prototypes from setup.h

2012-11-15T02:00:54Z

I noticed a couple of function prototypes for functions that no longer exist. Remove them. Signed-off-by: Anton Blanchard Signed-off-by: Benjamin Herrenschmidt

powerpc: Move most of setup.h out of uapi

2012-11-15T02:00:51Z

Most of setup.h should not be exported to userspace, so move it back. All we are left with is the asm-generic include to pick up the COMMAND_LINE_SIZE define. Signed-off-by: Anton Blanchard Signed-off-by: Benjamin Herrenschmidt

UAPI: (Scripted) Disintegrate arch/powerpc/include/asm

2012-10-09T08:47:26Z

Signed-off-by: David Howells Acked-by: Arnd Bergmann Acked-by: Thomas Gleixner Acked-by: Michael Kerrisk Acked-by: Paul E. McKenney Acked-by: Dave Jones

powerpc: Change memory_limit from phys_addr_t to unsigned long long

2012-09-07T01:44:30Z

There are some device-tree nodes, whose values are of type phys_addr_t. The phys_addr_t is variable sized based on the CONFIG_PHSY_T_64BIT. Change these to a fixed unsigned long long for consistency. This patch does the change only for memory_limit. The following is a list of such variables which need the change: 1) kernel_end, crashk_size - in arch/powerpc/kernel/machine_kexec.c 2) (struct resource *)crashk_res.start - We could export a local static variable from machine_kexec.c. Changing the above values might break the kexec-tools. So, I will fix kexec-tools first to handle the different sized values and then change the above. Suggested-by: Benjamin Herrenschmidt Signed-off-by: Suzuki K. Poulose Signed-off-by: Benjamin Herrenschmidt

Disintegrate asm/system.h for PowerPC

2012-03-28T17:30:02Z

Disintegrate asm/system.h for PowerPC. Signed-off-by: David Howells Acked-by: Benjamin Herrenschmidt cc: linuxppc-dev@lists.ozlabs.org