On Fri, Apr 08, 2016 at 03:50:23PM -0700, David Daney wrote:
> From: Ard Biesheuvel <ard.biesheu...@linaro.org>
> 
> There are two problems with the UEFI stub DT memory node removal
> routine:
> - it deletes nodes as it traverses the tree, which happens to work
>   but is not supported, as deletion invalidates the node iterator;
> - deleting memory nodes entirely may discard annotations in the form
>   of additional properties on the nodes.
> 
> Since the discovery of DT memory nodes occurs strictly before the
> UEFI init sequence, we can simply clear the memblock memory table
> before parsing the UEFI memory map. This way, it is no longer
> necessary to remove the nodes, so we can remove that logic from the
> stub as well.
> 
> Signed-off-by: Ard Biesheuvel <ard.biesheu...@linaro.org>
> Signed-off-by: David Daney <david.da...@cavium.com>
> ---
>  drivers/firmware/efi/arm-init.c    |  8 ++++++++
>  drivers/firmware/efi/libstub/fdt.c | 24 +-----------------------
>  2 files changed, 9 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/firmware/efi/arm-init.c b/drivers/firmware/efi/arm-init.c
> index aa1f743..5d6945b 100644
> --- a/drivers/firmware/efi/arm-init.c
> +++ b/drivers/firmware/efi/arm-init.c
> @@ -143,6 +143,14 @@ static __init void reserve_regions(void)
>       if (efi_enabled(EFI_DBG))
>               pr_info("Processing EFI memory map:\n");
>  
> +     /*
> +      * Discard memblocks discovered so far: if there are any at this
> +      * point, they originate from memory nodes in the DT, and UEFI
> +      * uses its own memory map instead.
> +      */
> +     memblock_dump_all();
> +     memblock_remove(0, ULLONG_MAX);
> +

Does this change need to be applied to any other architectures given
that deletion code has been removed from libstub below?

Cheers,
-- 
Steve

>       for_each_efi_memory_desc(&memmap, md) {
>               paddr = md->phys_addr;
>               npages = md->num_pages;
> diff --git a/drivers/firmware/efi/libstub/fdt.c 
> b/drivers/firmware/efi/libstub/fdt.c
> index 6dba78a..e58abfa 100644
> --- a/drivers/firmware/efi/libstub/fdt.c
> +++ b/drivers/firmware/efi/libstub/fdt.c
> @@ -24,7 +24,7 @@ efi_status_t update_fdt(efi_system_table_t *sys_table, void 
> *orig_fdt,
>                       unsigned long map_size, unsigned long desc_size,
>                       u32 desc_ver)
>  {
> -     int node, prev, num_rsv;
> +     int node, num_rsv;
>       int status;
>       u32 fdt_val32;
>       u64 fdt_val64;
> @@ -54,28 +54,6 @@ efi_status_t update_fdt(efi_system_table_t *sys_table, 
> void *orig_fdt,
>               goto fdt_set_fail;
>  
>       /*
> -      * Delete any memory nodes present. We must delete nodes which
> -      * early_init_dt_scan_memory may try to use.
> -      */
> -     prev = 0;
> -     for (;;) {
> -             const char *type;
> -             int len;
> -
> -             node = fdt_next_node(fdt, prev, NULL);
> -             if (node < 0)
> -                     break;
> -
> -             type = fdt_getprop(fdt, node, "device_type", &len);
> -             if (type && strncmp(type, "memory", len) == 0) {
> -                     fdt_del_node(fdt, node);
> -                     continue;
> -             }
> -
> -             prev = node;
> -     }
> -
> -     /*
>        * Delete all memory reserve map entries. When booting via UEFI,
>        * kernel will use the UEFI memory map to find reserved regions.
>        */
> -- 
> 1.8.3.1
> 
> 
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