@@ -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);
@@ -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)
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 <takahiro.akashi@linaro.org> Reviewed-by: Will Deacon <will.deacon@arm.com> Acked-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Dennis Chen <dennis.chen@arm.com> Cc: linux-mm@kvack.org Cc: Andrew Morton <akpm@linux-foundation.org> --- include/linux/memblock.h | 1 + mm/memblock.c | 44 +++++++++++++++++++++++++++++--------------- 2 files changed, 30 insertions(+), 15 deletions(-)