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>

1 files changed, 161 insertions, 61 deletions

diff --git a/arch/x86/boot/compressed/eboot.c b/arch/x86/boot/compressed/eboot.c
index beb07a4529ac..5c0dc55f2387 100644
--- 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;