Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754991AbcDNLKl (ORCPT ); Thu, 14 Apr 2016 07:10:41 -0400 Received: from mail-io0-f169.google.com ([209.85.223.169]:33786 "EHLO mail-io0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753931AbcDNLKg (ORCPT ); Thu, 14 Apr 2016 07:10:36 -0400 MIME-Version: 1.0 In-Reply-To: <20160414110210.GA11788@e103986-lin> References: <1460155828-8690-1-git-send-email-ddaney.cavm@gmail.com> <1460155828-8690-2-git-send-email-ddaney.cavm@gmail.com> <20160414110210.GA11788@e103986-lin> Date: Thu, 14 Apr 2016 13:10:35 +0200 Message-ID: Subject: Re: [PATCH v16 1/6] efi: ARM/arm64: ignore DT memory nodes instead of removing them From: Ard Biesheuvel To: Steve Capper Cc: David Daney , Will Deacon , "linux-arm-kernel@lists.infradead.org" , Rob Herring , Frank Rowand , Grant Likely , Pawel Moll , Ian Campbell , Kumar Gala , Ganapatrao Kulkarni , Robert Richter , Matt Fleming , Mark Rutland , Catalin Marinas , "devicetree@vger.kernel.org" , "linux-efi@vger.kernel.org" , "linux-kernel@vger.kernel.org" , David Daney Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3868 Lines: 103 On 14 April 2016 at 13:02, Steve Capper wrote: > On Fri, Apr 08, 2016 at 03:50:23PM -0700, David Daney wrote: >> From: Ard Biesheuvel >> >> 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 >> Signed-off-by: David Daney >> --- >> 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 >> >> >> _______________________________________________ >> linux-arm-kernel mailing list >> linux-arm-kernel@lists.infradead.org >> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >>