On 14 April 2016 at 13:02, Steve Capper <steve.capper@xxxxxxx> wrote:
> On Fri, Apr 08, 2016 at 03:50:23PM -0700, David Daney wrote:
>> From: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx>
>>
>> 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.biesheuvel@xxxxxxxxxx>
>> Signed-off-by: David Daney <david.daney@xxxxxxxxxx>
>> ---
>> 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?
>
The 'generic' libstub code below is only used by ARM, so we're safe
here in that regard.
>> 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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>> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>>
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