diff options
| -rw-r--r-- | Documentation/admin-guide/kernel-parameters.txt | 22 | ||||
| -rw-r--r-- | include/linux/mm.h | 2 | ||||
| -rw-r--r-- | mm/memblock.c | 117 |
3 files changed, 141 insertions, 0 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index b600df82669d..56e18b1a520d 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -5710,6 +5710,28 @@ them. If <base> is less than 0x10000, the region is assumed to be I/O ports; otherwise it is memory. + reserve_mem= [RAM] + Format: nn[KNG]:<align>:<label> + Reserve physical memory and label it with a name that + other subsystems can use to access it. This is typically + used for systems that do not wipe the RAM, and this command + line will try to reserve the same physical memory on + soft reboots. Note, it is not guaranteed to be the same + location. For example, if anything about the system changes + or if booting a different kernel. It can also fail if KASLR + places the kernel at the location of where the RAM reservation + was from a previous boot, the new reservation will be at a + different location. + Any subsystem using this feature must add a way to verify + that the contents of the physical memory is from a previous + boot, as there may be cases where the memory will not be + located at the same location. + + The format is size:align:label for example, to request + 12 megabytes of 4096 alignment for ramoops: + + reserve_mem=12M:4096:oops ramoops.mem_name=oops + reservetop= [X86-32,EARLY] Format: nn[KMG] Reserves a hole at the top of the kernel virtual diff --git a/include/linux/mm.h b/include/linux/mm.h index 9849dfda44d4..077fb589b88a 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -4263,4 +4263,6 @@ static inline bool pfn_is_unaccepted_memory(unsigned long pfn) void vma_pgtable_walk_begin(struct vm_area_struct *vma); void vma_pgtable_walk_end(struct vm_area_struct *vma); +int reserve_mem_find_by_name(const char *name, phys_addr_t *start, phys_addr_t *size); + #endif /* _LINUX_MM_H */ diff --git a/mm/memblock.c b/mm/memblock.c index 33a8b6f7b626..adb5a3c4bf06 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -2242,6 +2242,123 @@ void __init memblock_free_all(void) totalram_pages_add(pages); } +/* Keep a table to reserve named memory */ +#define RESERVE_MEM_MAX_ENTRIES 8 +#define RESERVE_MEM_NAME_SIZE 16 +struct reserve_mem_table { + char name[RESERVE_MEM_NAME_SIZE]; + phys_addr_t start; + phys_addr_t size; +}; +static struct reserve_mem_table reserved_mem_table[RESERVE_MEM_MAX_ENTRIES]; +static int reserved_mem_count; + +/* Add wildcard region with a lookup name */ +static void __init reserved_mem_add(phys_addr_t start, phys_addr_t size, + const char *name) +{ + struct reserve_mem_table *map; + + map = &reserved_mem_table[reserved_mem_count++]; + map->start = start; + map->size = size; + strscpy(map->name, name); +} + +/** + * reserve_mem_find_by_name - Find reserved memory region with a given name + * @name: The name that is attached to a reserved memory region + * @start: If found, holds the start address + * @size: If found, holds the size of the address. + * + * @start and @size are only updated if @name is found. + * + * Returns: 1 if found or 0 if not found. + */ +int reserve_mem_find_by_name(const char *name, phys_addr_t *start, phys_addr_t *size) +{ + struct reserve_mem_table *map; + int i; + + for (i = 0; i < reserved_mem_count; i++) { + map = &reserved_mem_table[i]; + if (!map->size) + continue; + if (strcmp(name, map->name) == 0) { + *start = map->start; + *size = map->size; + return 1; + } + } + return 0; +} +EXPORT_SYMBOL_GPL(reserve_mem_find_by_name); + +/* + * Parse reserve_mem=nn:align:name + */ +static int __init reserve_mem(char *p) +{ + phys_addr_t start, size, align, tmp; + char *name; + char *oldp; + int len; + + if (!p) + return -EINVAL; + + /* Check if there's room for more reserved memory */ + if (reserved_mem_count >= RESERVE_MEM_MAX_ENTRIES) + return -EBUSY; + + oldp = p; + size = memparse(p, &p); + if (!size || p == oldp) + return -EINVAL; + + if (*p != ':') + return -EINVAL; + + align = memparse(p+1, &p); + if (*p != ':') + return -EINVAL; + + /* + * memblock_phys_alloc() doesn't like a zero size align, + * but it is OK for this command to have it. + */ + if (align < SMP_CACHE_BYTES) + align = SMP_CACHE_BYTES; + + name = p + 1; + len = strlen(name); + + /* name needs to have length but not too big */ + if (!len || len >= RESERVE_MEM_NAME_SIZE) + return -EINVAL; + + /* Make sure that name has text */ + for (p = name; *p; p++) { + if (!isspace(*p)) + break; + } + if (!*p) + return -EINVAL; + + /* Make sure the name is not already used */ + if (reserve_mem_find_by_name(name, &start, &tmp)) + return -EBUSY; + + start = memblock_phys_alloc(size, align); + if (!start) + return -ENOMEM; + + reserved_mem_add(start, size, name); + + return 1; +} +__setup("reserve_mem=", reserve_mem); + #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_ARCH_KEEP_MEMBLOCK) static const char * const flagname[] = { [ilog2(MEMBLOCK_HOTPLUG)] = "HOTPLUG", |