diff options
Diffstat (limited to 'mm/mm_init.c')
| -rw-r--r-- | mm/mm_init.c | 30 |
1 files changed, 30 insertions, 0 deletions
diff --git a/mm/mm_init.c b/mm/mm_init.c index 7fd48d2d5064..bd7071c32a44 100644 --- a/mm/mm_init.c +++ b/mm/mm_init.c @@ -45,6 +45,13 @@ struct page *mem_map; EXPORT_SYMBOL(mem_map); #endif +/* + * high_memory defines the upper bound on direct map memory, then end + * of ZONE_NORMAL. + */ +void *high_memory; +EXPORT_SYMBOL(high_memory); + #ifdef CONFIG_DEBUG_MEMORY_INIT int __meminitdata mminit_loglevel; @@ -1778,6 +1785,27 @@ static bool arch_has_descending_max_zone_pfns(void) return IS_ENABLED(CONFIG_ARC) && !IS_ENABLED(CONFIG_ARC_HAS_PAE40); } +static void set_high_memory(void) +{ + phys_addr_t highmem = memblock_end_of_DRAM(); + + /* + * Some architectures (e.g. ARM) set high_memory very early and + * use it in arch setup code. + * If an architecture already set high_memory don't overwrite it + */ + if (high_memory) + return; + +#ifdef CONFIG_HIGHMEM + if (arch_has_descending_max_zone_pfns() || + highmem > PFN_PHYS(arch_zone_lowest_possible_pfn[ZONE_HIGHMEM])) + highmem = PFN_PHYS(arch_zone_lowest_possible_pfn[ZONE_HIGHMEM]); +#endif + + high_memory = phys_to_virt(highmem - 1) + 1; +} + /** * free_area_init - Initialise all pg_data_t and zone data * @max_zone_pfn: an array of max PFNs for each zone @@ -1900,6 +1928,8 @@ void __init free_area_init(unsigned long *max_zone_pfn) /* disable hash distribution for systems with a single node */ fixup_hashdist(); + + set_high_memory(); } /** |