@@ -319,6 +319,35 @@ efi_status_t __efiapi efi_pe_entry(efi_handle_t handle,
return status;
}
+/*
+ * efi_allocate_virtmap() - create a pool allocation for the virtmap
+ *
+ * Create an allocation that is of sufficient size to hold all the memory
+ * descriptors that will be passed to SetVirtualAddressMap() to inform the
+ * firmware about the virtual mapping that will be used under the OS to call
+ * into the firmware.
+ */
+efi_status_t efi_alloc_virtmap(efi_memory_desc_t **virtmap,
+ unsigned long *desc_size, u32 *desc_ver)
+{
+ unsigned long size, mmap_key;
+ efi_status_t status;
+
+ /*
+ * Use the size of the current memory map as an upper bound for the
+ * size of the buffer we need to pass to SetVirtualAddressMap() to
+ * cover all EFI_MEMORY_RUNTIME regions.
+ */
+ size = 0;
+ status = efi_bs_call(get_memory_map, &size, NULL, &mmap_key, desc_size,
+ desc_ver);
+ if (status != EFI_BUFFER_TOO_SMALL)
+ return EFI_LOAD_ERROR;
+
+ return efi_bs_call(allocate_pool, EFI_LOADER_DATA, size,
+ (void **)virtmap);
+}
+
/*
* efi_get_virtmap() - create a virtual mapping for the EFI memory map
*
@@ -334,6 +363,8 @@ void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size,
efi_memory_desc_t *in, *out = runtime_map;
int l;
+ *count = 0;
+
for (l = 0; l < map_size; l += desc_size) {
u64 paddr, size;
@@ -885,6 +885,8 @@ efi_status_t allocate_new_fdt_and_exit_boot(void *handle,
void *get_fdt(unsigned long *fdt_size);
+efi_status_t efi_alloc_virtmap(efi_memory_desc_t **virtmap,
+ unsigned long *desc_size, u32 *desc_ver);
void efi_get_virtmap(efi_memory_desc_t *memory_map, unsigned long map_size,
unsigned long desc_size, efi_memory_desc_t *runtime_map,
int *count);
@@ -199,7 +199,7 @@ static efi_status_t update_fdt_memmap(void *fdt, struct efi_boot_memmap *map)
struct exit_boot_struct {
efi_memory_desc_t *runtime_map;
- int *runtime_entry_count;
+ int runtime_entry_count;
void *new_fdt_addr;
};
@@ -213,7 +213,7 @@ static efi_status_t exit_boot_func(struct efi_boot_memmap *map,
* entries so that we can pass it straight to SetVirtualAddressMap()
*/
efi_get_virtmap(*map->map, *map->map_size, *map->desc_size,
- p->runtime_map, p->runtime_entry_count);
+ p->runtime_map, &p->runtime_entry_count);
return update_fdt_memmap(p->new_fdt_addr, map);
}
@@ -246,26 +246,18 @@ efi_status_t allocate_new_fdt_and_exit_boot(void *handle,
unsigned long map_size, desc_size, buff_size;
u32 desc_ver;
unsigned long mmap_key;
- efi_memory_desc_t *memory_map, *runtime_map;
+ efi_memory_desc_t *memory_map;
efi_status_t status;
- int runtime_entry_count;
struct efi_boot_memmap map;
struct exit_boot_struct priv;
- map.map = &runtime_map;
map.map_size = &map_size;
map.desc_size = &desc_size;
map.desc_ver = &desc_ver;
map.key_ptr = &mmap_key;
map.buff_size = &buff_size;
- /*
- * Get a copy of the current memory map that we will use to prepare
- * the input for SetVirtualAddressMap(). We don't have to worry about
- * subsequent allocations adding entries, since they could not affect
- * the number of EFI_MEMORY_RUNTIME regions.
- */
- status = efi_get_memory_map(&map);
+ status = efi_alloc_virtmap(&priv.runtime_map, &desc_size, &desc_ver);
if (status != EFI_SUCCESS) {
efi_err("Unable to retrieve UEFI memory map.\n");
return status;
@@ -289,10 +281,7 @@ efi_status_t allocate_new_fdt_and_exit_boot(void *handle,
goto fail_free_new_fdt;
}
- runtime_entry_count = 0;
- priv.runtime_map = runtime_map;
- priv.runtime_entry_count = &runtime_entry_count;
- priv.new_fdt_addr = (void *)*new_fdt_addr;
+ priv.new_fdt_addr = (void *)*new_fdt_addr;
status = efi_exit_boot_services(handle, &map, &priv, exit_boot_func);
@@ -304,8 +293,8 @@ efi_status_t allocate_new_fdt_and_exit_boot(void *handle,
/* Install the new virtual address map */
svam = efi_system_table->runtime->set_virtual_address_map;
- status = svam(runtime_entry_count * desc_size, desc_size,
- desc_ver, runtime_map);
+ status = svam(priv.runtime_entry_count * desc_size, desc_size,
+ desc_ver, priv.runtime_map);
/*
* We are beyond the point of no return here, so if the call to
@@ -337,7 +326,7 @@ efi_status_t allocate_new_fdt_and_exit_boot(void *handle,
efi_free(MAX_FDT_SIZE, *new_fdt_addr);
fail:
- efi_system_table->boottime->free_pool(runtime_map);
+ efi_bs_call(free_pool, priv.runtime_map);
return EFI_LOAD_ERROR;
}
The virt map is a set of efi_memory_desc_t descriptors that are passed to SetVirtualAddressMap() to inform the firmware about the desired virtual mapping of the regions marked as EFI_MEMORY_RUNTIME. The only reason we currently call the efi_get_memory_map() helper is that it gives us an allocation that is guaranteed to be of sufficient size. However, efi_get_memory_map() has grown some additional complexity over the years, and today, we're actually better off calling the EFI boot service directly with a zero size, which tells us how much memory should be enough for the virt map. Signed-off-by: Ard Biesheuvel <ardb@kernel.org> --- drivers/firmware/efi/libstub/efi-stub.c | 31 ++++++++++++++++++++ drivers/firmware/efi/libstub/efistub.h | 2 ++ drivers/firmware/efi/libstub/fdt.c | 27 +++++------------ 3 files changed, 41 insertions(+), 19 deletions(-)