[U-Boot] [PATCH 09/14] efi_loader: Implement memory allocation and map

Simon Glass sjg at chromium.org
Sun Jan 31 16:23:58 CET 2016


Hi Alexander,

On 14 January 2016 at 22:06, Alexander Graf <agraf at suse.de> wrote:
> Due to popular request, this is a separate patch implementing all of the memory
> allocation and memory mapping bits.
>
> We assume we always have a linear RAM map. At TOM U-Boot resides. Inside of
> U-Boot there is the runtime region that we need to explicitly expose via the
> EFI memory map. Below U-Boot, we reserve 128MB of RAM for LOADER_DATA.
>
> Signed-off-by: Alexander Graf <agraf at suse.de>
> ---
>  lib/efi_loader/efi_boottime.c     | 99 ++++++++++++++++++++++++++++++++++++++-
>  lib/efi_loader/efi_image_loader.c | 28 ++++++++++-
>  2 files changed, 123 insertions(+), 4 deletions(-)
>
> diff --git a/lib/efi_loader/efi_boottime.c b/lib/efi_loader/efi_boottime.c
> index 45217ef..ff3f969 100644
> --- a/lib/efi_loader/efi_boottime.c
> +++ b/lib/efi_loader/efi_boottime.c
> @@ -98,6 +98,8 @@ static void efi_restore_tpl(unsigned long old_tpl)
>  static void *efi_alloc(uint64_t len, int memory_type)
>  {
>         switch (memory_type) {
> +       case EFI_LOADER_DATA:
> +               return efi_loader_alloc(len);
>         default:
>                 return malloc(len);
>         }
> @@ -143,16 +145,109 @@ static efi_status_t efi_free_pages(uint64_t memory, unsigned long pages)
>         return EFI_EXIT(EFI_SUCCESS);
>  }
>
> -/* Will be implemented in a later patch */
> +/*
> + * Returns the EFI memory map. In our case, this looks pretty simple:
> + *
> + *  ____________________________    TOM
> + * |                            |
> + * |    Second half of U-Boot   |

What does 'second half' mean?

> + * |____________________________|   &__efi_runtime_stop
> + * |                            |
> + * |    EFI Runtime Services    |
> + * |____________________________|   &__efi_runtime_start
> + * |                            |
> + * |    First half of U-Boot    |
> + * |____________________________|   start of EFI loader allocation space
> + * |                            |
> + * |          Free RAM          |
> + * |____________________________|   CONFIG_SYS_SDRAM_BASE
> + *
> + * All pointers are extended to live on a 4k boundary. After exiting the boot
> + * services, only the EFI Runtime Services chunk of memory stays alive.
> + */
>  static efi_status_t efi_get_memory_map(unsigned long *memory_map_size,
>                                struct efi_mem_desc *memory_map,
>                                unsigned long *map_key,
>                                unsigned long *descriptor_size,
>                                uint32_t *descriptor_version)
>  {
> +       struct efi_mem_desc efi_memory_map[] = {
> +               {
> +                       /* RAM before U-Boot */
> +                       .type = EFI_CONVENTIONAL_MEMORY,
> +                       .attribute = 1 << EFI_MEMORY_WB_SHIFT,
> +               },
> +               {
> +                       /* First half of U-Boot */
> +                       .type = EFI_LOADER_DATA,
> +                       .attribute = 1 << EFI_MEMORY_WB_SHIFT,
> +               },
> +               {
> +                       /* EFI Runtime Services */
> +                       .type = EFI_RUNTIME_SERVICES_CODE,
> +                       .attribute = (1 << EFI_MEMORY_WB_SHIFT) |
> +                                    (1ULL << EFI_MEMORY_RUNTIME_SHIFT),
> +               },
> +               {
> +                       /* Second half of U-Boot */
> +                       .type = EFI_LOADER_DATA,
> +                       .attribute = 1 << EFI_MEMORY_WB_SHIFT,
> +               },
> +       };
> +       ulong runtime_start, runtime_end, runtime_len_pages, runtime_len;
> +
>         EFI_ENTRY("%p, %p, %p, %p, %p", memory_map_size, memory_map, map_key,
>                   descriptor_size, descriptor_version);
> -       return EFI_EXIT(EFI_UNSUPPORTED);
> +
> +       runtime_start = (ulong)&__efi_runtime_start & ~0xfffULL;
> +       runtime_end = ((ulong)&__efi_runtime_stop + 0xfff) & ~0xfffULL;
> +       runtime_len_pages = (runtime_end - runtime_start) >> 12;
> +       runtime_len = runtime_len_pages << 12;
> +
> +       /* Fill in where normal RAM is (up to U-Boot's top of stack) */
> +       efi_memory_map[0].num_pages = gd->start_addr_sp >> 12;
> +#ifdef CONFIG_SYS_SDRAM_BASE

If not defined, what happens?

> +       efi_memory_map[0].physical_start = CONFIG_SYS_SDRAM_BASE;
> +       efi_memory_map[0].virtual_start = CONFIG_SYS_SDRAM_BASE;
> +       efi_memory_map[0].num_pages -= CONFIG_SYS_SDRAM_BASE >> 12;
> +#endif
> +
> +       /* Give us some space for the stack */
> +       efi_memory_map[0].num_pages -= (16 * 1024 * 1024) >> 12;
> +
> +       /* Reserve the EFI loader pool */
> +       efi_memory_map[0].num_pages -= EFI_LOADER_POOL_SIZE >> 12;
> +
> +       /* Cut out the runtime services */
> +       efi_memory_map[2].physical_start = runtime_start;
> +       efi_memory_map[2].virtual_start = efi_memory_map[2].physical_start;
> +       efi_memory_map[2].num_pages = runtime_len_pages;
> +
> +       /* Allocate the rest to U-Boot */
> +       efi_memory_map[1].physical_start = efi_memory_map[0].physical_start +
> +                                          (efi_memory_map[0].num_pages << 12);
> +       efi_memory_map[1].virtual_start = efi_memory_map[1].physical_start;
> +       efi_memory_map[1].num_pages = (runtime_start -
> +                                      efi_memory_map[1].physical_start) >> 12;
> +
> +       efi_memory_map[3].physical_start = runtime_start + runtime_len;
> +       efi_memory_map[3].virtual_start = efi_memory_map[3].physical_start;
> +       efi_memory_map[3].num_pages = (gd->ram_top -
> +                                      efi_memory_map[3].physical_start) >> 12;
> +
> +       *memory_map_size = sizeof(efi_memory_map);
> +
> +       if (descriptor_size)
> +               *descriptor_size = sizeof(struct efi_mem_desc);
> +
> +       if (*memory_map_size < sizeof(efi_memory_map)) {
> +               return EFI_EXIT(EFI_BUFFER_TOO_SMALL);
> +       }
> +
> +       if (memory_map)
> +               memcpy(memory_map, efi_memory_map, sizeof(efi_memory_map));
> +
> +       return EFI_EXIT(EFI_SUCCESS);
>  }
>
>  static efi_status_t efi_allocate_pool(int pool_type, unsigned long size, void **buffer)
> diff --git a/lib/efi_loader/efi_image_loader.c b/lib/efi_loader/efi_image_loader.c
> index a7788bf..67c4b06 100644
> --- a/lib/efi_loader/efi_image_loader.c
> +++ b/lib/efi_loader/efi_image_loader.c
> @@ -29,10 +29,34 @@ efi_status_t efi_return_handle(void *handle, efi_guid_t *protocol,
>         return EFI_SUCCESS;
>  }
>
> -/* Will be implemented in a later patch */
> +/*
> + * EFI payloads potentially want to load pretty big images into memory,
> + * so our small malloc region isn't enough for them. However, they usually
> + * don't need a smart allocator either.
> + *
> + * So instead give them a really dumb one. We just reserve EFI_LOADER_POOL_SIZE
> + * bytes from 16MB below the stack start to give the stack some space.
> + * Then every allocation gets a 4k aligned chunk from it. We never free.
> + */
>  void *efi_loader_alloc(uint64_t len)
>  {
> -       return NULL;
> +       static unsigned long loader_pool;
> +       void *r;
> +
> +       if (!loader_pool) {
> +               loader_pool = ((gd->start_addr_sp >> 12) << 12) -
> +                             (16 * MB) - EFI_LOADER_POOL_SIZE;

I think it would be better to reserve this in board_f() with a
reserve...() function. Perhaps store the address in global_data.

> +       }
> +
> +       len = ROUND_UP(len, 4096);
> +       /* Out of memory */
> +       if ((loader_pool + len) >= (gd->relocaddr - TOTAL_MALLOC_LEN))

debug() here?

> +               return NULL;
> +
> +       r = (void *)loader_pool;
> +       loader_pool += len;
> +
> +       return r;
>  }
>
>  /*
> --
> 2.1.4

Regards,
Simon


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