efi/libstub: Allocate headspace in efi_get_memory_map()

[linux.git] / drivers / firmware / efi / libstub / efi-stub-helper.c

diff --git a/drivers/firmware/efi/libstub/efi-stub-helper.c b/drivers/firmware/efi/libstub/efi-stub-helper.c
index 3bd127f953151dff89d0563db13deb12046e4315..29368ac6922139586110322dd3068e8b74c12ade 100644 (file)
--- a/drivers/firmware/efi/libstub/efi-stub-helper.c
+++ b/drivers/firmware/efi/libstub/efi-stub-helper.c
@@ -41,6 +41,8 @@ static unsigned long __chunk_size = EFI_READ_CHUNK_SIZE;
 #define EFI_ALLOC_ALIGN                EFI_PAGE_SIZE
 #endif
 
+#define EFI_MMAP_NR_SLACK_SLOTS        8
+
 struct file_info {
        efi_file_handle_t *handle;
        u64 size;
@@ -63,49 +65,62 @@ void efi_printk(efi_system_table_t *sys_table_arg, char *str)
        }
 }
 
+static inline bool mmap_has_headroom(unsigned long buff_size,
+                                    unsigned long map_size,
+                                    unsigned long desc_size)
+{
+       unsigned long slack = buff_size - map_size;
+
+       return slack / desc_size >= EFI_MMAP_NR_SLACK_SLOTS;
+}
+
 efi_status_t efi_get_memory_map(efi_system_table_t *sys_table_arg,
-                               efi_memory_desc_t **map,
-                               unsigned long *map_size,
-                               unsigned long *desc_size,
-                               u32 *desc_ver,
-                               unsigned long *key_ptr)
+                               struct efi_boot_memmap *map)
 {
        efi_memory_desc_t *m = NULL;
        efi_status_t status;
        unsigned long key;
        u32 desc_version;
 
-       *map_size = sizeof(*m) * 32;
+       *map->desc_size =       sizeof(*m);
+       *map->map_size =        *map->desc_size * 32;
+       *map->buff_size =       *map->map_size;
 again:
-       /*
-        * Add an additional efi_memory_desc_t because we're doing an
-        * allocation which may be in a new descriptor region.
-        */
-       *map_size += sizeof(*m);
        status = efi_call_early(allocate_pool, EFI_LOADER_DATA,
-                               *map_size, (void **)&m);
+                               *map->map_size, (void **)&m);
        if (status != EFI_SUCCESS)
                goto fail;
 
-       *desc_size = 0;
+       *map->desc_size = 0;
        key = 0;
-       status = efi_call_early(get_memory_map, map_size, m,
-                               &key, desc_size, &desc_version);
-       if (status == EFI_BUFFER_TOO_SMALL) {
+       status = efi_call_early(get_memory_map, map->map_size, m,
+                               &key, map->desc_size, &desc_version);
+       if (status == EFI_BUFFER_TOO_SMALL ||
+           !mmap_has_headroom(*map->buff_size, *map->map_size,
+                              *map->desc_size)) {
                efi_call_early(free_pool, m);
+               /*
+                * Make sure there is some entries of headroom so that the
+                * buffer can be reused for a new map after allocations are
+                * no longer permitted.  Its unlikely that the map will grow to
+                * exceed this headroom once we are ready to trigger
+                * ExitBootServices()
+                */
+               *map->map_size += *map->desc_size * EFI_MMAP_NR_SLACK_SLOTS;
+               *map->buff_size = *map->map_size;
                goto again;
        }
 
        if (status != EFI_SUCCESS)
                efi_call_early(free_pool, m);
 
-       if (key_ptr && status == EFI_SUCCESS)
-               *key_ptr = key;
-       if (desc_ver && status == EFI_SUCCESS)
-               *desc_ver = desc_version;
+       if (map->key_ptr && status == EFI_SUCCESS)
+               *map->key_ptr = key;
+       if (map->desc_ver && status == EFI_SUCCESS)
+               *map->desc_ver = desc_version;
 
 fail:
-       *map = m;
+       *map->map = m;
        return status;
 }
 
@@ -113,13 +128,20 @@ fail:
 unsigned long get_dram_base(efi_system_table_t *sys_table_arg)
 {
        efi_status_t status;
-       unsigned long map_size;
+       unsigned long map_size, buff_size;
        unsigned long membase  = EFI_ERROR;
        struct efi_memory_map map;
        efi_memory_desc_t *md;
+       struct efi_boot_memmap boot_map;
 
-       status = efi_get_memory_map(sys_table_arg, (efi_memory_desc_t **)&map.map,
-                                   &map_size, &map.desc_size, NULL, NULL);
+       boot_map.map =          (efi_memory_desc_t **)&map.map;
+       boot_map.map_size =     &map_size;
+       boot_map.desc_size =    &map.desc_size;
+       boot_map.desc_ver =     NULL;
+       boot_map.key_ptr =      NULL;
+       boot_map.buff_size =    &buff_size;
+
+       status = efi_get_memory_map(sys_table_arg, &boot_map);
        if (status != EFI_SUCCESS)
                return membase;
 
@@ -144,15 +166,22 @@ efi_status_t efi_high_alloc(efi_system_table_t *sys_table_arg,
                            unsigned long size, unsigned long align,
                            unsigned long *addr, unsigned long max)
 {
-       unsigned long map_size, desc_size;
+       unsigned long map_size, desc_size, buff_size;
        efi_memory_desc_t *map;
        efi_status_t status;
        unsigned long nr_pages;
        u64 max_addr = 0;
        int i;
+       struct efi_boot_memmap boot_map;
+
+       boot_map.map =          ↦
+       boot_map.map_size =     &map_size;
+       boot_map.desc_size =    &desc_size;
+       boot_map.desc_ver =     NULL;
+       boot_map.key_ptr =      NULL;
+       boot_map.buff_size =    &buff_size;
 
-       status = efi_get_memory_map(sys_table_arg, &map, &map_size, &desc_size,
-                                   NULL, NULL);
+       status = efi_get_memory_map(sys_table_arg, &boot_map);
        if (status != EFI_SUCCESS)
                goto fail;
 
@@ -230,14 +259,21 @@ efi_status_t efi_low_alloc(efi_system_table_t *sys_table_arg,
                           unsigned long size, unsigned long align,
                           unsigned long *addr)
 {
-       unsigned long map_size, desc_size;
+       unsigned long map_size, desc_size, buff_size;
        efi_memory_desc_t *map;
        efi_status_t status;
        unsigned long nr_pages;
        int i;
+       struct efi_boot_memmap boot_map;
+
+       boot_map.map =          ↦
+       boot_map.map_size =     &map_size;
+       boot_map.desc_size =    &desc_size;
+       boot_map.desc_ver =     NULL;
+       boot_map.key_ptr =      NULL;
+       boot_map.buff_size =    &buff_size;
 
-       status = efi_get_memory_map(sys_table_arg, &map, &map_size, &desc_size,
-                                   NULL, NULL);
+       status = efi_get_memory_map(sys_table_arg, &boot_map);
        if (status != EFI_SUCCESS)
                goto fail;