The patch below does not apply to the 4.17-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From d7609f4210cb716c11abfe2bfb5997191095d00b Mon Sep 17 00:00:00 2001

From: "mike.travis@hpe.com" mike.travis@hpe.com Date: Thu, 24 May 2018 15:17:14 -0500 Subject: [PATCH] x86/platform/UV: Add kernel parameter to set memory block size

Add a kernel parameter that allows setting UV memory block size. This is to provide an adjustment for new forms of PMEM and other DIMM memory that might require alignment restrictions other than scanning the global address table for the required minimum alignment. The value set will be further adjusted by both the GAM range table scan as well as restrictions imposed by set_memory_block_size_order().

Signed-off-by: Mike Travis mike.travis@hpe.com Reviewed-by: Andrew Banman andrew.banman@hpe.com Cc: Andrew Morton akpm@linux-foundation.org Cc: Dimitri Sivanich dimitri.sivanich@hpe.com Cc: Linus Torvalds torvalds@linux-foundation.org Cc: Peter Zijlstra peterz@infradead.org Cc: Russ Anderson russ.anderson@hpe.com Cc: Thomas Gleixner tglx@linutronix.de Cc: dan.j.williams@intel.com Cc: jgross@suse.com Cc: kirill.shutemov@linux.intel.com Cc: mhocko@suse.com Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/lkml/20180524201711.854849120@stormcage.americas.sgi... Signed-off-by: Ingo Molnar mingo@kernel.org

diff --git a/arch/x86/kernel/apic/x2apic_uv_x.c b/arch/x86/kernel/apic/x2apic_uv_x.c index 2270a777d647..d492752f79e1 100644 --- a/arch/x86/kernel/apic/x2apic_uv_x.c +++ b/arch/x86/kernel/apic/x2apic_uv_x.c @@ -396,6 +396,17 @@ EXPORT_SYMBOL(uv_hub_info_version); /* Default UV memory block size is 2GB */ static unsigned long mem_block_size = (2UL << 30);

+/* Kernel parameter to specify UV mem block size */ +static int parse_mem_block_size(char *ptr) +{ + unsigned long size = memparse(ptr, NULL); + + /* Size will be rounded down by set_block_size() below */ + mem_block_size = size; + return 0; +} +early_param("uv_memblksize", parse_mem_block_size); + static __init int adj_blksize(u32 lgre) { unsigned long base = (unsigned long)lgre << UV_GAM_RANGE_SHFT;