We need to limit the max memory based on Linux page table format. Add checks to limit memory based on pte size. Also limit the memory based on MAX_PHSYSMEM_BITS.
Signed-off-by: Aneesh Kumar K.V <aneesh.ku...@linux.vnet.ibm.com> --- Changes from V1: * Update commit message. 4K can handle 64TB * Also limit based on MAX_PHSYSMEM_BITS arch/powerpc/include/asm/mmu.h | 8 ++++++++ arch/powerpc/include/asm/sparsemem.h | 2 -- arch/powerpc/kernel/prom.c | 25 ++++++++++++++++++++++--- 3 files changed, 30 insertions(+), 5 deletions(-) diff --git a/arch/powerpc/include/asm/mmu.h b/arch/powerpc/include/asm/mmu.h index 3d5abfe6ba67..d44d49093c8d 100644 --- a/arch/powerpc/include/asm/mmu.h +++ b/arch/powerpc/include/asm/mmu.h @@ -200,6 +200,14 @@ static inline void assert_pte_locked(struct mm_struct *mm, unsigned long addr) # include <asm/mmu-8xx.h> #endif +#ifdef CONFIG_PHYS_64BIT +/* + * Max supported memory on 64bit system is 64TB. + */ +#define MAX_PHYSMEM_BITS 46 +#else +#define MAX_PHYSMEM_BITS 32 +#endif #endif /* __KERNEL__ */ #endif /* _ASM_POWERPC_MMU_H_ */ diff --git a/arch/powerpc/include/asm/sparsemem.h b/arch/powerpc/include/asm/sparsemem.h index f6fc0ee813d7..fc3808378893 100644 --- a/arch/powerpc/include/asm/sparsemem.h +++ b/arch/powerpc/include/asm/sparsemem.h @@ -11,8 +11,6 @@ #define SECTION_SIZE_BITS 24 #define MAX_PHYSADDR_BITS 46 -#define MAX_PHYSMEM_BITS 46 - #endif /* CONFIG_SPARSEMEM */ #ifdef CONFIG_MEMORY_HOTPLUG diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c index 308c5e15676b..c09315b32ca7 100644 --- a/arch/powerpc/kernel/prom.c +++ b/arch/powerpc/kernel/prom.c @@ -698,9 +698,28 @@ void __init early_init_devtree(void *params) #endif reserve_crashkernel(); early_reserve_mem(); - - /* Ensure that total memory size is page-aligned. */ - limit = ALIGN(memory_limit ?: memblock_phys_mem_size(), PAGE_SIZE); + /* + * if not specified limit the memory based on the pfn count that + * we can fit in pte_t. Also ensure that total memory size is + * page-aligned. + */ + if (!memory_limit) { + int bit_count; + phys_addr_t pte_mem_limit; + + limit = memblock_phys_mem_size(); + if (limit >= (1ULL << MAX_PHYSMEM_BITS)) + limit = (1ULL << MAX_PHYSMEM_BITS) - 1; + + BUILD_BUG_ON(sizeof(pte_basic_t) > 8); + bit_count = (sizeof(pte_basic_t) * 8) - PTE_RPN_SHIFT + PAGE_SHIFT; + pte_mem_limit = ~0ULL >> (64 - bit_count); + if (limit > pte_mem_limit) + limit = pte_mem_limit; + } else + limit = memory_limit; + + limit = ALIGN(limit, PAGE_SIZE); memblock_enforce_memory_limit(limit); memblock_allow_resize(); -- 2.1.4 _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev