Add a new function to "adjust" the current fixed UV memory block size of 2GB so it can be changed to a different physical boundary. This is out of necessity so arch dependent code can accommodate specific BIOS requirements which can align these new PMEM modules at less than the default boundaries.

A "set order" type of function was used to insure that the memory block size will be a power of two value without requiring a validity check. 64GB was chosen as the upper limit for memory block size values to accommodate upcoming 4PB systems which have 6 more bits of physical address space (46 becoming 52).

Signed-off-by: Mike Travis mike.travis@hpe.com Reviewed-by: Andrew Banman andrew.banman@hpe.com Cc: stable@vger.kernel.org --- v2: Update description --- arch/x86/mm/init_64.c | 20 ++++++++++++++++---- include/linux/memory.h | 1 + 2 files changed, 17 insertions(+), 4 deletions(-)

--- linux.orig/arch/x86/mm/init_64.c +++ linux/arch/x86/mm/init_64.c @@ -1350,16 +1350,28 @@ int kern_addr_valid(unsigned long addr) /* Amount of ram needed to start using large blocks */ #define MEM_SIZE_FOR_LARGE_BLOCK (64UL << 30)

+/* Adjustable memory block size */ +static unsigned long set_memory_block_size; +int __init set_memory_block_size_order(unsigned int order) +{ + unsigned long size = 1UL << order; + + if (size > MEM_SIZE_FOR_LARGE_BLOCK || size < MIN_MEMORY_BLOCK_SIZE) + return -EINVAL; + + set_memory_block_size = size; + return 0; +} + static unsigned long probe_memory_block_size(void) { unsigned long boot_mem_end = max_pfn << PAGE_SHIFT; unsigned long bz;

- /* If this is UV system, always set 2G block size */ - if (is_uv_system()) { - bz = MAX_BLOCK_SIZE; + /* If memory block size has been set, then use it */ + bz = set_memory_block_size; + if (bz) goto done; - }

/* Use regular block if RAM is smaller than MEM_SIZE_FOR_LARGE_BLOCK */ if (boot_mem_end < MEM_SIZE_FOR_LARGE_BLOCK) { --- linux.orig/include/linux/memory.h +++ linux/include/linux/memory.h @@ -38,6 +38,7 @@ struct memory_block {

int arch_get_memory_phys_device(unsigned long start_pfn); unsigned long memory_block_size_bytes(void); +int set_memory_block_size_order(unsigned int order);

/* These states are exposed to userspace as text strings in sysfs */ #define MEM_ONLINE (1<<0) /* exposed to userspace */

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