From 4c546b8a34690ca858e50f2017b8bb6e358365d1 Mon Sep 17 00:00:00 2001 From: AKASHI Takahiro Date: Mon, 3 Apr 2017 11:23:54 +0900 Subject: memblock: add memblock_clear_nomap() This function, with a combination of memblock_mark_nomap(), will be used in a later kdump patch for arm64 when it temporarily isolates some range of memory from the other memory blocks in order to create a specific kernel mapping at boot time. Signed-off-by: AKASHI Takahiro Reviewed-by: Ard Biesheuvel Signed-off-by: Catalin Marinas --- mm/memblock.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'mm') diff --git a/mm/memblock.c b/mm/memblock.c index 696f06d17c4e..2f4ca8104ea4 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -804,6 +804,18 @@ int __init_memblock memblock_mark_nomap(phys_addr_t base, phys_addr_t size) return memblock_setclr_flag(base, size, 1, MEMBLOCK_NOMAP); } +/** + * memblock_clear_nomap - Clear flag MEMBLOCK_NOMAP for a specified region. + * @base: the base phys addr of the region + * @size: the size of the region + * + * Return 0 on success, -errno on failure. + */ +int __init_memblock memblock_clear_nomap(phys_addr_t base, phys_addr_t size) +{ + return memblock_setclr_flag(base, size, 0, MEMBLOCK_NOMAP); +} + /** * __next_reserved_mem_region - next function for for_each_reserved_region() * @idx: pointer to u64 loop variable -- cgit v1.2.3-59-g8ed1b From c9ca9b4e2198a4dbeb83739460d4a7ff9ffed24f Mon Sep 17 00:00:00 2001 From: AKASHI Takahiro Date: Mon, 3 Apr 2017 11:23:55 +0900 Subject: memblock: add memblock_cap_memory_range() Add memblock_cap_memory_range() which will remove all the memblock regions except the memory range specified in the arguments. In addition, rework is done on memblock_mem_limit_remove_map() to re-implement it using memblock_cap_memory_range(). This function, like memblock_mem_limit_remove_map(), will not remove memblocks with MEMMAP_NOMAP attribute as they may be mapped and accessed later as "device memory." See the commit a571d4eb55d8 ("mm/memblock.c: add new infrastructure to address the mem limit issue"). This function is used, in a succeeding patch in the series of arm64 kdump suuport, to limit the range of usable memory, or System RAM, on crash dump kernel. (Please note that "mem=" parameter is of little use for this purpose.) Signed-off-by: AKASHI Takahiro Reviewed-by: Will Deacon Acked-by: Catalin Marinas Acked-by: Dennis Chen Cc: linux-mm@kvack.org Cc: Andrew Morton Reviewed-by: Ard Biesheuvel Signed-off-by: Catalin Marinas --- include/linux/memblock.h | 1 + mm/memblock.c | 44 +++++++++++++++++++++++++++++--------------- 2 files changed, 30 insertions(+), 15 deletions(-) (limited to 'mm') diff --git a/include/linux/memblock.h b/include/linux/memblock.h index e82daffcfc44..4ce24a376262 100644 --- a/include/linux/memblock.h +++ b/include/linux/memblock.h @@ -336,6 +336,7 @@ phys_addr_t memblock_mem_size(unsigned long limit_pfn); phys_addr_t memblock_start_of_DRAM(void); phys_addr_t memblock_end_of_DRAM(void); void memblock_enforce_memory_limit(phys_addr_t memory_limit); +void memblock_cap_memory_range(phys_addr_t base, phys_addr_t size); void memblock_mem_limit_remove_map(phys_addr_t limit); bool memblock_is_memory(phys_addr_t addr); int memblock_is_map_memory(phys_addr_t addr); diff --git a/mm/memblock.c b/mm/memblock.c index 2f4ca8104ea4..b049c9b2dba8 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -1543,11 +1543,37 @@ void __init memblock_enforce_memory_limit(phys_addr_t limit) (phys_addr_t)ULLONG_MAX); } +void __init memblock_cap_memory_range(phys_addr_t base, phys_addr_t size) +{ + int start_rgn, end_rgn; + int i, ret; + + if (!size) + return; + + ret = memblock_isolate_range(&memblock.memory, base, size, + &start_rgn, &end_rgn); + if (ret) + return; + + /* remove all the MAP regions */ + for (i = memblock.memory.cnt - 1; i >= end_rgn; i--) + if (!memblock_is_nomap(&memblock.memory.regions[i])) + memblock_remove_region(&memblock.memory, i); + + for (i = start_rgn - 1; i >= 0; i--) + if (!memblock_is_nomap(&memblock.memory.regions[i])) + memblock_remove_region(&memblock.memory, i); + + /* truncate the reserved regions */ + memblock_remove_range(&memblock.reserved, 0, base); + memblock_remove_range(&memblock.reserved, + base + size, (phys_addr_t)ULLONG_MAX); +} + void __init memblock_mem_limit_remove_map(phys_addr_t limit) { - struct memblock_type *type = &memblock.memory; phys_addr_t max_addr; - int i, ret, start_rgn, end_rgn; if (!limit) return; @@ -1558,19 +1584,7 @@ void __init memblock_mem_limit_remove_map(phys_addr_t limit) if (max_addr == (phys_addr_t)ULLONG_MAX) return; - ret = memblock_isolate_range(type, max_addr, (phys_addr_t)ULLONG_MAX, - &start_rgn, &end_rgn); - if (ret) - return; - - /* remove all the MAP regions above the limit */ - for (i = end_rgn - 1; i >= start_rgn; i--) { - if (!memblock_is_nomap(&type->regions[i])) - memblock_remove_region(type, i); - } - /* truncate the reserved regions */ - memblock_remove_range(&memblock.reserved, max_addr, - (phys_addr_t)ULLONG_MAX); + memblock_cap_memory_range(0, max_addr); } static int __init_memblock memblock_search(struct memblock_type *type, phys_addr_t addr) -- cgit v1.2.3-59-g8ed1b