x86: EFI stub support for large memory maps

This patch fixes a problem with EFI memory maps larger than 128 entries
when booting using the EFI stub, which results in overflowing e820_map
in boot_params and an eventual halt when checking the map size in
sanitize_e820_map().

If the number of map entries is greater than what can fit in e820_map,
add the extra entries to the setup_data list using type SETUP_E820_EXT.
These extra entries are then picked up when the setup_data list is
parsed in parse_e820_ext().

Signed-off-by: Linn Crosetto <linn@hp.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>

diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index beb07a4529ac0f41ecfc6f832f4c31fc0976a986..5c0dc55f2387ff3d9524716deb778d6df522d402 100644 (file)
--- a/arch/x86/boot/compressed/eboot.c
+++ b/arch/x86/boot/compressed/eboot.c
@@ -519,71 +519,47 @@ fail:
        return NULL;
 }
 
-static efi_status_t exit_boot(struct boot_params *boot_params,
-                             void *handle)
+static void add_e820ext(struct boot_params *params,
+                       struct setup_data *e820ext, u32 nr_entries)
 {
-       struct efi_info *efi = &boot_params->efi_info;
-       struct e820entry *e820_map = &boot_params->e820_map[0];
-       struct e820entry *prev = NULL;
-       unsigned long size, key, desc_size, _size;
-       efi_memory_desc_t *mem_map;
+       struct setup_data *data;
        efi_status_t status;
-       __u32 desc_version;
-       bool called_exit = false;
-       u8 nr_entries;
-       int i;
-
-get_map:
-       status = efi_get_memory_map(sys_table, &mem_map, &size, &desc_size,
-                                   &desc_version, &key);
-
-       if (status != EFI_SUCCESS)
-               return status;
+       unsigned long size;
 
-       memcpy(&efi->efi_loader_signature, EFI_LOADER_SIGNATURE, sizeof(__u32));
-       efi->efi_systab = (unsigned long)sys_table;
-       efi->efi_memdesc_size = desc_size;
-       efi->efi_memdesc_version = desc_version;
-       efi->efi_memmap = (unsigned long)mem_map;
-       efi->efi_memmap_size = size;
+       e820ext->type = SETUP_E820_EXT;
+       e820ext->len = nr_entries * sizeof(struct e820entry);
+       e820ext->next = 0;
 
-#ifdef CONFIG_X86_64
-       efi->efi_systab_hi = (unsigned long)sys_table >> 32;
-       efi->efi_memmap_hi = (unsigned long)mem_map >> 32;
-#endif
+       data = (struct setup_data *)(unsigned long)params->hdr.setup_data;
 
-       /* Might as well exit boot services now */
-       status = efi_call_phys2(sys_table->boottime->exit_boot_services,
-                               handle, key);
-       if (status != EFI_SUCCESS) {
-               /*
-                * ExitBootServices() will fail if any of the event
-                * handlers change the memory map. In which case, we
-                * must be prepared to retry, but only once so that
-                * we're guaranteed to exit on repeated failures instead
-                * of spinning forever.
-                */
-               if (called_exit)
-                       goto free_mem_map;
+       while (data && data->next)
+               data = (struct setup_data *)(unsigned long)data->next;
 
-               called_exit = true;
-               efi_call_phys1(sys_table->boottime->free_pool, mem_map);
-               goto get_map;
-       }
+       if (data)
+               data->next = (unsigned long)e820ext;
+       else
+               params->hdr.setup_data = (unsigned long)e820ext;
+}
 
-       /* Historic? */
-       boot_params->alt_mem_k = 32 * 1024;
+static efi_status_t setup_e820(struct boot_params *params,
+                              struct setup_data *e820ext, u32 e820ext_size)
+{
+       struct e820entry *e820_map = &params->e820_map[0];
+       struct efi_info *efi = &params->efi_info;
+       struct e820entry *prev = NULL;
+       u32 nr_entries;
+       u32 nr_desc;
+       int i;
 
-       /*
-        * Convert the EFI memory map to E820.
-        */
        nr_entries = 0;
-       for (i = 0; i < size / desc_size; i++) {
+       nr_desc = efi->efi_memmap_size / efi->efi_memdesc_size;
+
+       for (i = 0; i < nr_desc; i++) {
                efi_memory_desc_t *d;
                unsigned int e820_type = 0;
-               unsigned long m = (unsigned long)mem_map;
+               unsigned long m = efi->efi_memmap;
 
-               d = (efi_memory_desc_t *)(m + (i * desc_size));
+               d = (efi_memory_desc_t *)(m + (i * efi->efi_memdesc_size));
                switch (d->type) {
                case EFI_RESERVED_TYPE:
                case EFI_RUNTIME_SERVICES_CODE:
@@ -620,18 +596,142 @@ get_map:
 
                /* Merge adjacent mappings */
                if (prev && prev->type == e820_type &&
-                   (prev->addr + prev->size) == d->phys_addr)
+                   (prev->addr + prev->size) == d->phys_addr) {
                        prev->size += d->num_pages << 12;
-               else {
-                       e820_map->addr = d->phys_addr;
-                       e820_map->size = d->num_pages << 12;
-                       e820_map->type = e820_type;
-                       prev = e820_map++;
-                       nr_entries++;
+                       continue;
                }
+
+               if (nr_entries == ARRAY_SIZE(params->e820_map)) {
+                       u32 need = (nr_desc - i) * sizeof(struct e820entry) +
+                                  sizeof(struct setup_data);
+
+                       if (!e820ext || e820ext_size < need)
+                               return EFI_BUFFER_TOO_SMALL;
+
+                       /* boot_params map full, switch to e820 extended */
+                       e820_map = (struct e820entry *)e820ext->data;
+               }
+
+               e820_map->addr = d->phys_addr;
+               e820_map->size = d->num_pages << PAGE_SHIFT;
+               e820_map->type = e820_type;
+               prev = e820_map++;
+               nr_entries++;
        }
 
-       boot_params->e820_entries = nr_entries;
+       if (nr_entries > ARRAY_SIZE(params->e820_map)) {
+               u32 nr_e820ext = nr_entries - ARRAY_SIZE(params->e820_map);
+
+               add_e820ext(params, e820ext, nr_e820ext);
+               nr_entries -= nr_e820ext;
+       }
+
+       params->e820_entries = (u8)nr_entries;
+
+       return EFI_SUCCESS;
+}
+
+static efi_status_t alloc_e820ext(u32 nr_desc, struct setup_data **e820ext,
+                                 u32 *e820ext_size)
+{
+       efi_status_t status;
+       unsigned long size;
+
+       size = sizeof(struct setup_data) +
+               sizeof(struct e820entry) * nr_desc;
+
+       if (*e820ext) {
+               efi_call_phys1(sys_table->boottime->free_pool, *e820ext);
+               *e820ext = NULL;
+               *e820ext_size = 0;
+       }
+
+       status = efi_call_phys3(sys_table->boottime->allocate_pool,
+                               EFI_LOADER_DATA, size, e820ext);
+
+       if (status == EFI_SUCCESS)
+               *e820ext_size = size;
+
+       return status;
+}
+
+static efi_status_t exit_boot(struct boot_params *boot_params,
+                             void *handle)
+{
+       struct efi_info *efi = &boot_params->efi_info;
+       unsigned long map_sz, key, desc_size;
+       efi_memory_desc_t *mem_map;
+       struct setup_data *e820ext;
+       __u32 e820ext_size;
+       __u32 nr_desc, prev_nr_desc;
+       efi_status_t status;
+       __u32 desc_version;
+       bool called_exit = false;
+       u8 nr_entries;
+       int i;
+
+       nr_desc = 0;
+       e820ext = NULL;
+       e820ext_size = 0;
+
+get_map:
+       status = efi_get_memory_map(sys_table, &mem_map, &map_sz, &desc_size,
+                                   &desc_version, &key);
+
+       if (status != EFI_SUCCESS)
+               return status;
+
+       prev_nr_desc = nr_desc;
+       nr_desc = map_sz / desc_size;
+       if (nr_desc > prev_nr_desc &&
+           nr_desc > ARRAY_SIZE(boot_params->e820_map)) {
+               u32 nr_e820ext = nr_desc - ARRAY_SIZE(boot_params->e820_map);
+
+               status = alloc_e820ext(nr_e820ext, &e820ext, &e820ext_size);
+               if (status != EFI_SUCCESS)
+                       goto free_mem_map;
+
+               efi_call_phys1(sys_table->boottime->free_pool, mem_map);
+               goto get_map; /* Allocated memory, get map again */
+       }
+
+       memcpy(&efi->efi_loader_signature, EFI_LOADER_SIGNATURE, sizeof(__u32));
+       efi->efi_systab = (unsigned long)sys_table;
+       efi->efi_memdesc_size = desc_size;
+       efi->efi_memdesc_version = desc_version;
+       efi->efi_memmap = (unsigned long)mem_map;
+       efi->efi_memmap_size = map_sz;
+
+#ifdef CONFIG_X86_64
+       efi->efi_systab_hi = (unsigned long)sys_table >> 32;
+       efi->efi_memmap_hi = (unsigned long)mem_map >> 32;
+#endif
+
+       /* Might as well exit boot services now */
+       status = efi_call_phys2(sys_table->boottime->exit_boot_services,
+                               handle, key);
+       if (status != EFI_SUCCESS) {
+               /*
+                * ExitBootServices() will fail if any of the event
+                * handlers change the memory map. In which case, we
+                * must be prepared to retry, but only once so that
+                * we're guaranteed to exit on repeated failures instead
+                * of spinning forever.
+                */
+               if (called_exit)
+                       goto free_mem_map;
+
+               called_exit = true;
+               efi_call_phys1(sys_table->boottime->free_pool, mem_map);
+               goto get_map;
+       }
+
+       /* Historic? */
+       boot_params->alt_mem_k = 32 * 1024;
+
+       status = setup_e820(boot_params, e820ext, e820ext_size);
+       if (status != EFI_SUCCESS)
+               return status;
 
        return EFI_SUCCESS;